Abstract
Background
Rhegmatogenous retinal detachment (RRD) with macular involvement may lead to persistent visual impairment despite successful anatomical repair. Different intravitreal tamponade agents used during pars plana vitrectomy (PPV) may variably affect retinal and choroidal microcirculation. This study aimed to evaluate longitudinal changes in retinal vascular layers and choriocapillaris flow (CCF) using optical coherence tomography angiography (OCT-A) in macula-off RRD eyes treated with perfluoropropane (C3F8) gas or silicone oil (SO) tamponade.
Methods
In this prospective cohort study, 30 eyes of 30 patients with macula-off RRD who underwent PPV using either C3F8 gas (n = 13) or 1000-cSt SO (n = 17) were included, along with 30 healthy fellow eyes as controls. OCT-A measurements were obtained at 2, 3, 5, and 6 months postoperatively. Foveal and parafoveal superficial capillary plexus (SCPVD), deep capillary plexus (DCPVD) vessel density, foveal avascular zone (FAZ), CCF, and macular thickness were analyzed and compared longitudinally and with healthy fellow eyes.
Results
Parafoveal SCPVD and macular thickness were significantly reduced in the SO group compared with controls at all time points (p < 0.05). CCF measurements in both 1-mm and 2-mm radius areas were significantly lower in the SO group at 5 and 6 months, even after SO removal (p < 0.05). In contrast, the C3F8 group showed transient reductions in DCPVD at 2 and 3 months, with subsequent recovery. FAZ area did not differ significantly between groups. Correlation analysis revealed a strong negative correlation between changes in SCPVD and changes in BCVA in the SO group.
Conclusions
SO tamponade is associated with persistent impairment of macular microcirculation and CCF that does not fully recover after oil removal, whereas retinal vascular changes following C3F8 tamponade appear largely reversible. OCT-A may be a valuable noninvasive tool for guiding tamponade selection and determining optimal timing of SO removal in macula-off RRD surgery.
Keywords: Deep capillary plexus, Intravitreal tamponade, Optical coherence tomography angiography, Rhegmatogenous retinal detachment, Superficial capillary plexus
Introduction
Rhegmatogenous retinal detachment (RRD) is a sight-threatening condition that requires urgent surgical intervention, as delayed or inadequate treatment may result in irreversible vision loss. Pars plana vitrectomy (PPV) has become an effective and widely accepted surgical technique for the management of RRD owing to advances in vitreoretinal surgical technology [1]. During PPV, intravitreal tamponade agents such as silicone oil (SO) or expansile gas are commonly used to provide surface tension over retinal breaks and to prevent the migration of fluid into the subretinal space until stable adhesion forms between the retinal pigment epithelium (RPE) and the neurosensory retina.
Several studies have demonstrated that SO tamponade may reduce retinal and choroidal microcirculation following PPV [2, 3]. Decreased retinal and choroidal blood flow in SO-filled eyes has been associated with microangiopathy and may predispose the retina to ischemic damage. In contrast to the retinal circulation, choroidal blood flow exhibits limited autoregulatory capacity [4]. Consequently, alterations in the choroid—particularly within the choriocapillaris—may adversely affect the outer retinal layers, especially in the foveal region where intrinsic retinal vasculature is absent. The choroidal circulation is also essential for maintaining thermal stability of the outer retina, a factor known to influence visual acuity [5]. Previous studies have further suggested that the inner retinal layers are particularly vulnerable under hypoxic conditions, as they rely primarily on retinal vascular supply [6]. Consistent with this, thinning of the inner retinal layers has been reported in eyes undergoing PPV with SO tamponade compared with those treated using gas tamponade [7].
Optical coherence tomography angiography (OCT-A) is a non-invasive, highly reproducible imaging modality that enables quantitative visualization of retinal and choroidal microvasculature [8]. OCT-A allows detailed assessment of vessel density in both the superficial and deep capillary plexuses, evaluation of the foveal avascular zone, and analysis of choroidal blood flow [9–12].
The aim of the present study was to evaluate changes in choriocapillaris flow (CCF) and retinal vascular layers using OCT-A in patients with RRD who underwent PPV with either perfluoropropane (C3F8) gas or SO tamponade, and to compare these findings with those of healthy fellow eyes. A better understanding of these microvascular changes may influence intravitreal tamponade selection in RRD surgery and help determine the optimal timing for SO removal in eyes treated with SO endotamponade.
Materials and methods
This prospective cohort study included patients with macula-off RRD who underwent PPV with either C3F8 or 1000-cSt SO tamponade at Ulucanlar Eye Training and Research Hospital. The study was approved by the local ethics committee of Ankara Numune Training and Research Hospital with the number E-18-2295 and adhered to the tenets outlined in the Declaration of Helsinki. Written and verbal informed consent was obtained from all patients.
All patients underwent a comprehensive ophthalmic examination at baseline and at each follow-up visit. Examinations included best-corrected visual acuity (BCVA) and intraocular pressure (IOP) measurements, slit-lamp biomicroscopy of the anterior segment, and dilated fundus examination. Visual acuity was measured using a Snellen chart and converted to logarithm of the minimum angle of resolution (LogMAR) units for statistical analysis. Since the exact onset of retinal detachment at the time of diagnosis cannot be determined, the period from the onset of patients’ visual complaints to the day of surgery was considered the duration of retinal detachment. Optical coherence tomography angiography (OCT-A) images were obtained using a commercial OCT system (AngioVue, RTVue XR Avanti SD-OCT; Optovue, Fremont, CA, USA) after pharmacological pupil dilation. OCT-A examinations were performed at 2, 3, 5, and 6 months after PPV in all patients. In the SO group, OCT-A measurements at 2 and 3 months were obtained while the vitreous cavity was filled with SO. SO was removed at a mean of 4 months postoperatively, and OCT-A measurements were subsequently repeated at 5 and 6 months in oil-free eyes. In the C3F8 gas group, all postoperative examinations were performed after complete absorption of the gas tamponade. For each eye, a 6 × 6-mm scan centered on the fovea was acquired. Vessel density of the superficial capillary plexus (SCPVD) and deep capillary plexus (DCPVD), choriocapillaris flow (CCF), and parafoveal retinal thickness were measured and compared between study eyes and healthy fellow eyes.
Patients younger than 18 years of age; those with refractive errors greater than ± 6.0 diopters; an interocular axial length difference exceeding 1 mm; a history of ocular surgery other than uncomplicated cataract extraction; retinal detachment symptoms lasting longer than one month; or proliferative vitreoretinopathy grade other than A or B, according to the Retinal Society Terminology Committee classification (1983), were excluded. In addition, patients with systemic diseases that could affect retinal or choroidal circulation, such as diabetes mellitus, hypertension, or vasculitis, were excluded. Eyes with coexisting ocular conditions, including ocular trauma, diabetic retinopathy, uveitis, glaucoma, degenerative myopia, hereditary or acquired retinal diseases, and amblyopia, were also excluded. Further exclusion criteria included postoperative IOP greater than 21 mmHg requiring medical treatment, poor-quality OCT-A images with a signal strength index < 6/10, poor fixation due to low vision, and the presence of cystoid macular edema, epiretinal membrane, or submacular residual fluid that could interfere with OCT-A measurements.
Surgical procedure
Transconjunctival 25-gauge minimally invasive vitreous surgery was performed in all cases under local anesthesia using retrobulbar injection. All procedures were conducted by a single experienced vitreoretinal surgeon (YÖE) using the same vitrectomy platform (Constellation® Vision System 25+, Alcon, Fort Worth, TX, USA). Transconjunctival sclerotomies were created in the inferotemporal, superotemporal, and superonasal quadrants at an angle of approximately 30° parallel to the limbus, followed by insertion of 25-gauge trocars. After completion of core vitrectomy, 360° scleral indentation was performed, and the peripheral vitreous was meticulously removed, particularly around retinal breaks. Retinal reattachment was achieved using perfluorocarbon liquid, and subretinal fluid was drained through the retinal tear, hole, or iatrogenic retinotomy. Endolaser photocoagulation was applied around all retinal breaks, holes, and retinotomy sites. At the final stage of surgery, the appropriate endotamponade was selected, and either air–gas exchange with 14% C3F8 or injection of 1000-cSt SO was performed. The choice of intravitreal tamponade was based on the number and location of retinal breaks, duration of retinal detachment, postoperative positioning requirements, travel considerations, and the surgeon’s clinical judgment. After removal of the trocars, only leaking sclerotomy sites were sutured using 8 − 0 Vicryl. Postoperatively, patients were advised to maintain an appropriate head position for one week. All patients received topical antibiotics and corticosteroids for one month. In eyes treated with SO tamponade, SO removal was performed approximately four months after the initial PPV.
Data collection
OCT-A imaging was performed using a commercial OCT system (AngioVue, RTVue XR Avanti SD-OCT; Optovue, Fremont, CA, USA) after pharmacological pupil dilation. Pupil dilation was achieved using 1% tropicamide and 2.5% phenylephrine hydrochloride administered three times at five-minute intervals. Automatic segmentation of the superficial and deep retinal layers was performed using the device’s built-in software. The SCP was defined as extending from approximately 3 μm below the inner limiting membrane to 15 μm below the inner plexiform layer (IPL). The DCP was defined as extending from 15 μm to 70 μm below the IPL, with an approximate thickness of 55 μm. Parafoveal vessel density and full-thickness macular thickness (MT) measurements were obtained according to the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. The innermost area with a diameter of 1.0 mm was defined as the foveal region, and the ring-shaped area with an outer diameter of 3.0 mm and an inner diameter of 1.0 mm was defined as the parafoveal region. Foveal avascular zone (FAZ) area (mm²) and CCF within a 1-mm radius (mm²) were measured automatically. CCF measurements within a 2-mm radius were obtained by averaging three separate manual measurements. OCT-A images were analyzed by an experienced independent evaluator (MSK). Patients with poor image features such as a low signal strength index (< 6/10), blinking artifacts, motion or double image artifacts, poor fixation, and segmentation errors were selected and rescanned to obtain adequate images. Images with a signal strength index ≥ 6 were used for quantitative evaluation.
Statistical analysis
Statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS, version 20.0; IBM Corp., Armonk, NY, USA). Descriptive statistics were expressed as mean ± standard deviation (minimum–maximum), frequency, and percentage. Categorical variables were analyzed using the Pearson chi-square test or Fisher’s exact test, as appropriate. Normality of data distribution was assessed using both visual methods (histograms and probability plots) and analytical methods (Shapiro–Wilk test). The Mann–Whitney U test was used to compare two independent groups, while the Friedman test was applied for comparisons among three or more related groups for non-normally distributed variables. When a significant difference was detected among dependent groups, post hoc pairwise comparisons were performed using the Wilcoxon signed-rank test with Bonferroni correction. The relationship between the variables was evaluated using the Spearman Correlation Test. Correlation coefficients were interpreted as follows: 0-0.25 weak relationship, 0.26–0.50 moderate relationship, 0.51–0.75 strong relationship, and 0.76-1.00 very strong relationship. A p value < 0.05 was considered statistically significant.
Results
A total of 60 eyes were included in the study, comprising 30 eyes of 30 patients with macula-off rhegmatogenous retinal detachment and 30 untreated healthy fellow eyes. Of the 30 study eyes that underwent pars plana vitrectomy, 13 received perfluoropropane (C3F8) gas tamponade and 17 received 1000-cSt SO tamponade. The mean age of the patients was 57.7 ± 7.9 years in the C3F8 group and 59.0 ± 12.5 years in the SO group. The duration of retinal detachment was determined to be an average of 13.2 ± 8.8 days in the C3F8 group and 13.3 ± 9.3 days in the SO group. Baseline demographic and clinical characteristics are summarized in Table 1. There were no statistically significant differences between the two study groups in terms of age, sex, or duration of retinal detachment (all p > 0.05).
Table 1.
Distribution of descriptive and clinical features among study groups
| C3F8 (n = 13) | SO (n = 17) | p | |
|---|---|---|---|
| Age (years), mean ± SD (min-max) | 57.7 ± 7.9 (41–70) | 59.0 ± 12.5 (33–86) | 0.711a |
| Gender, n (%) | |||
| Male | 8 (61.5) | 10 (58.8) | 0.880b |
| Female | 5 (38.5) | 7 (41.2) | |
| Lens, n (%) | |||
| Phakic | 7 (53.8) | 9 (52.9) | 0.961b |
| Pseudophakic | 6 (46.2) | 8 (47.1) | |
| Detachment Duration (days), mean ± SD (min-max) | 13.2 ± 8.8 (5–30) | 13.3 ± 9.3 (2–30) | 0.934a |
n: Number of patients; %: Column percentage; SD: Standard deviation; aMann-Whitney U Test; bPearson Chi-Square Test; cFisher’s Exact Test; SO: Silicone Oil
Mean BCVA and IOP values across follow-up visits are presented in Tables 2 and 3. In the C3F8 group, mean BCVA was significantly improved at postoperative months 3, 5, and 6 compared with the preoperative values (p < 0.001). A significant improvement in BCVA was also observed between postoperative months 2 and 6 (p < 0.001).
Table 2.
Distribution of mean BCVA over time between study groups and control groups, and within each study group itself
| n | Preoperative | 2nd month | 3rd month | 5th month | 6th month | p1 | ||
|---|---|---|---|---|---|---|---|---|
|
BCVA (LogMAR) |
C 3 F 8 | 13 | 1.95 ± 0.86 (1.1–3.1)cde | 0.47 ± 0.21 (0.2–0.8)e | 0.41 ± 0.29 (0-0.8) | 0.33 ± 0.24 (0-0.8) | 0.25 ± 0.21 (0-0.7) | < 0.001 |
| Control | 13 | 0.03 ± 0.06 (0-0.2) | 0.08 ± 0.19 (0-0.7) | 0.02 ± 0.03 (0-0.1) | 0.04 ± 0.07 (0-0.2) | 0.02 ± 0.04 (0-0.2) | 0.479 | |
| p 2 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | |||
| SO | 17 | 2.57 ± 0.87 (1.1–3.1)bcde | 0.95 ± 0.39 (0.2–2.1) | 0.82 ± 0.38 (0.1–1.6) | 0.73 ± 0.22 (0.3–1.1) | 0.66 ± 0.26 (0.3–1.1) | < 0.001 | |
| Control | 17 | 0.07 ± 0.06 (0-0.2) | 0.03 ± 0.04 (0-0.1) | 0.03 ± 0.05 (0-0.2) | 0.02 ± 0.05 (0-0.2) | 0.02 ± 0.04 (0-0.2) | 0.055 | |
| p 2 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
n: Number of eyes; Data are presented as “mean ± standard deviation (minimum-maximum)”; 1Friedman Test; 2Mann-Whitney U Test; aPost-hoc pairwise comparison showed a significant difference with “pre-op”; bPost-hoc pairwise comparison showed a significant difference with “2nd month”; cPost-hoc pairwise comparison showed a significant difference with “3rd month”; dPost-hoc pairwise comparison showed a significant difference with “5th month”; ePost-hoc pairwise comparison showed a significant difference with “6th month”; BCVA: Best Corrected Visual Acuity; SO: Silicone Oil
Table 3.
Distribution of IOP over time between study groups and control groups, and within each study group itself
| n | Preoperative | 2nd month | 3rd month | 5th month | 6th month | p1 | ||
|---|---|---|---|---|---|---|---|---|
| IOP | C 3 F 8 | 13 | 15.6 ± 3.1 (9–19) | 15.3 ± 2.4 (10–19) | 15.8 ± 1.6 (14–19) | 16.3 ± 2.5 (12–19) | 16.5 ± 2.5 (12–19) | 0.527 |
| Control | 13 | 17.1 ± 1.9 (14–19)b | 14.7 ± 2.6 (11–19) | 15.6 ± 2.5 (11–19) | 15.6 ± 2.3 (12–19) | 15.8 ± 2.4 (11–19) | 0.006 | |
| p 2 | 0.287 | 0.579 | 0.880 | 0.479 | 0.390 | |||
| SO | 17 | 15.1 ± 3.3 (8–19) | 16.2 ± 2.8 (11–19) | 16.0 ± 2.7 (11–19) | 16.3 ± 2.5 (12–19) | 16.4 ± 2.4 (12–19) | 0.575 | |
| Control | 17 | 16.7 ± 2.8 (9–19) | 14.8 ± 2.7 (11–19) | 15.5 ± 2.0 (11–19) | 15.9 ± 2.8 (12–19) | 16.1 ± 2.7 (11–19) | 0.388 | |
| p 2 | 0.099 | 0.140 | 0.518 | 0.734 | 0.760 |
n: Number of eyes; Data are presented as “mean ± standard deviation (minimum-maximum)”; 1Friedman Test; 2Mann-Whitney U Test; aPost-hoc pairwise comparison showed a significant difference with “pre-op”; bPost-hoc pairwise comparison showed a significant difference with “2nd month”; cPost-hoc pairwise comparison showed a significant difference with “3rd month”; dPost-hoc pairwise comparison showed a significant difference with “5th month”; ePost-hoc pairwise comparison showed a significant difference with “6th month”; IOP: Intraocular Pressure; SO: Silicone Oil
In the SO group, mean BCVA was significantly higher at all postoperative time points compared with baseline (p < 0.001). No significant difference in BCVA was observed between measurements obtained before SO removal (months 2 and 3) and those obtained after removal (months 5 and 6) (p > 0.05). Mean BCVA remained significantly lower in both tamponade groups compared with healthy fellow eyes at all follow-up visits (p < 0.001). There were no statistically significant differences in mean IOP values between study and control eyes at any time point, nor within either study group over time (p > 0.05).
Foveal and parafoveal SCPVD and DCPVD, as well as foveal and parafoveal MT measurements, are shown in Tables 4, 5 and 6. No statistically significant difference was observed in foveal SCPVD and DCPVD within the study groups themselves or between the study groups and healthy fellow eyes at any follow-up visit (p > 0.05). No statistically significant differences in parafoveal SCPVD were observed within the C3F8 group or between the C3F8 group and healthy fellow eyes at any follow-up visit (p > 0.05). In contrast, parafoveal SCPVD was significantly lower in the SO group compared with the control group at all time points (p < 0.05). Parafoveal DCPVD was significantly reduced in the C3F8 group compared with healthy fellow eyes at postoperative months 2 and 3 (p < 0.05), with no significant differences at later visits. Although lower DCPVD values were observed in the SO group compared with controls at all follow-up visits, these differences did not reach statistical significance (p > 0.05).
Table 4.
Distribution of SCPVD over time between study groups and control groups, and within each study group itself
| n | 2nd month | 3rd month | 5th month | 6th month | pd1 | |||
|---|---|---|---|---|---|---|---|---|
| SCPVD | Fovea | C 3 F 8 | 13 | 23.8 ± 6.6 (13.0-32.5) | 23.6 ± 6.5 (12.6–32.4) | 23.9 ± 6.6 (12.6–34.8) | 23.9 ± 8.4 (10.6–36.0) | 0.744 |
| Control | 13 | 23.4 ± 7.5 (10.3–35.0) | 23.7 ± 7.4 (10.2–35.0) | 23.6 ± 7.5 (8.3–32.8) | 23.8 ± 7.2 (10.3–33.6) | 0.819 | ||
| p | 0.880 | 0.920 | 0.801 | 0.960 | ||||
| Parafovea | C 3 F 8 | 13 | 50.2 ± 3.0 (45.2–54.9) | 50.8 ± 4.2 (42.7–57.7) | 50.6 ± 2.3 (47.2–54.1) | 50.9 ± 3.2 (45.3–56.1) | 0.613 | |
| Control | 13 | 51.7 ± 3.4 (44.7–56.2) | 52.2 ± 3.2 (44.7–56.2) | 55.6 ± 3.7 (44.2–56.3) | 53.5 ± 1.9 (50.3–57.1) | 0.293 | ||
| p | 0.204 | 0.390 | 0.101 | 0.051 | ||||
| Fovea | SO | 17 | 19.3 ± 7.6 (10.1–36.2) | 20.6 ± 8.5 (8.4–37.6) | 20.9 ± 5.8 (11.7–33.2) | 21.3 ± 7.4 (7.6–39.2) | 0.299 | |
| Control | 17 | 21.7 ± 6.0 (9.2–31.5) | 21.7 ± 5.3 (9.2–29.5) | 21.6 ± 5.4 (9.1–29.6) | 21.6 ± 5.4 (9.1–29.6) | 0.998 | ||
| p | 0.205 | 0.496 | 0.610 | 0.634 | ||||
| Parafovea | SO | 17 | 46.0 ± 5.5 (36.6–57.0) | 46.5 ± 5.3 (37.5–55.7) | 44.3 ± 5.0 (34.5–52.2) | 44.3 ± 5.9 (34.1–54.8) | 0.186 | |
| Control | 17 | 50.6 ± 6.3 (34.8–57.0) | 50.8 ± 5.5 (34.8–57.5) | 51.4 ± 3.4 (43.7–57.2) | 51.5 ± 4.1 (43.7–57.0) | 0.582 | ||
| p | 0.026 | 0.018 | < 0.001 | < 0.001 |
n: Number of eyes; Data are presented as “mean ± standard deviation (minimum-maximum)”; 1Friedman Test; 2Mann-Whitney U Test; SCPVD: Superficial Capillary Plexus Vessel Density; SO: Silicone Oil
Table 5.
Distribution of DCPVD over time between study groups and control groups, and within each study group itself
| n | 2nd month | 3rd month | 5th month | 6th month | pd1 | |||
|---|---|---|---|---|---|---|---|---|
| DCPVD | Fovea | C 3 F 8 | 13 | 36.8 ± 7.6 (21.4–45.1) | 36.0 ± 7.1 (22.9–45.1) | 36.4 ± 7.0 (22.2–44.1) | 36.5 ± 8.5 (20.4–50.0) | 0.744 |
| Control | 13 | 37.6 ± 7.8 (20.0–49.0) | 38.6 ± 6.0 (25.5–49.0) | 38.1 ± 7.4 (22.9–48.1) | 38.0 ± 6.5 (23.8–48.5) | 0.342 | ||
| p | 0.960 | 0.448 | 0.479 | 0.545 | ||||
| Parafovea | C 3 F 8 | 13 | 51.2 ± 1.5 (48.7–53.7) | 51.1 ± 2.5 (44.6–54.2) | 51.8 ± 3.0 (45.2–55.3) | 52.9 ± 3.6 (49.0-60.5) | 0.320 | |
| Control | 13 | 53.0 ± 2.2 (49.6–56.7) | 53.6 ± 2.6 (49.3–57.8) | 53.1 ± 3.3 (47.1–57.3) | 53.4 ± 3.3 (48.5–59.2) | 0.797 | ||
| p | 0.039 | 0.029 | 0.362 | 0.724 | ||||
| Fovea | SO | 17 | 34.1 ± 6.5 (22.8–46.0) | 34.3 ± 8.0 (22.8–48.5) | 35.1 ± 6.6 (22.0-46.4) | 34.7 ± 6.3 (22.0-46.4) | 0.807 | |
| Control | 17 | 37.8 ± 6.7 (26.0-48.7) | 37.8 ± 6.2 (26.0-49.3) | 37.9 ± 6.4 (25.0-47.8) | 38.0 ± 6.5 (25.0-49.8) | 0.918 | ||
| p | 0.122 | 0.160 | 0.205 | 0.160 | ||||
| Parafovea | SO | 17 | 52.9 ± 5.1 (41.4–59.7) | 52.7 ± 6.3 (42.5–62.8) | 51.4 ± 4.6 (45.5–60.4) | 51.5 ± 4.7 (43.4–60.1) | 0.358 | |
| Control | 17 | 54.9 ± 5.0 (46.1–62.3) | 53.6 ± 4.5 (46.6–60.3) | 53.5 ± 5.5 (43.9–63.9) | 53.3 ± 5.9 (43.9–63.3) | 0.206 | ||
| p | 0.375 | 0.683 | 0.205 | 0.454 |
n: Number of eyes; Data are presented as “mean ± standard deviation (minimum-maximum)”; 1Friedman Test; 2Mann-Whitney U Test; DCPVD: Deep Capillary Plexus Vessel Density; SO: Silicone Oil
Table 6.
Distribution of macular thickness over time between study groups and control groups, and within each study group itself
| n | 2nd month | 3rd month | 5th month | 6th month | pd1 | |||
|---|---|---|---|---|---|---|---|---|
| Macular Thickness | Fovea | C 3 F 8 | 13 | 253.7 ± 29.7 (223–326)cd | 254.2 ± 23.6 (228–298) | 260.5 ± 21.2 (230–288) | 258.7 ± 20.4 (233–285) | 0.005 |
| Control | 13 | 261.7 ± 19.6 (226–292) | 262.8 ± 21.6 (229–303) | 263.2 ± 22.8 (224–307) | 262.7 ± 20.6 (227–297) | 0.504 | ||
| p | 0.204 | 0.243 | 0.724 | 0.448 | ||||
| Parafovea | C 3 F 8 | 13 | 321.2 ± 18.6 (295–357)cd | 323.5 ± 16.6 (301–352) | 328.2 ± 13.4 (305–345) | 326.5 ± 11.2 (307–346) | 0.001 | |
| Control | 13 | 326.0 ± 16.5 (309–360) | 327.8 ± 18.9 (311–368) | 327.3 ± 18.2 (311–363) | 327.7 ± 17.6 (311–366) | 0.132 | ||
| p | 0.448 | 0.545 | 0.650 | 0.724 | ||||
| Fovea | SO | 17 | 226.4 ± 52.2 (131–320)d | 225.4 ± 39.4 (139–320)d | 238.4 ± 31.7 (177–293) | 241.6 ± 31.4 (177–293) | 0.004 | |
| Control | 17 | 253.2 ± 17.1 (213–278) | 253.6 ± 17.4 (213–278) | 252.6 ± 17.3 (214–280) | 253.6 ± 17.8 (214–284) | 0.716 | ||
| p | 0.041 | 0.002 | 0.182 | 0.245 | ||||
| Parafovea | SO | 17 | 280.1 ± 28.8 (225–340)cd | 280.8 ± 26.6 (225–340)d | 302.4 ± 19.6 (270–340) | 304.5 ± 21.0 (270–340) | < 0.001 | |
| Control | 17 | 322.4 ± 11.9 (299–342) | 322.6 ± 11.4 (299–340) | 321.0 ± 12.2 (297–342) | 322.1 ± 12.6 (298–346) | 0.071 | ||
| p | < 0.001 | < 0.001 | 0.005 | 0.009 |
n: Number of eyes; Data are presented as “mean ± standard deviation (minimum-maximum)”; 1Friedman Test; 2Mann-Whitney U Test; aPost-hoc pairwise comparison showed a significant difference at “month 2”; bPost-hoc pairwise comparison showed a significant difference at “month 3”; cPost-hoc pairwise comparison showed a significant difference at “month 5”; dPost-hoc pairwise comparison showed a significant difference at “month 6”; SO: Silicone Oil
There was no statistically significant difference in foveal and parafoveal MT between the C3F8 group and the control group at any time point (p > 0.05). In contrast, in the SO group, foveal MT was significantly reduced at months 2 and 3, and parafoveal MT was significantly reduced at all follow-up visits compared to the healthy fellow eye (p < 0.05). Representative OCT-A images from a patient treated with SO tamponade, illustrating SCPVD and parafoveal MT at different time points, are shown in Fig. 1.
Fig. 1.
Optical coherence tomography angiography images of a 33-year-old woman (DE) with macula-off rhegmatogenous retinal detachment who underwent silicone oil (SO) as intravitreal tamponade. The superficial capillary plexus vessel density (SCPVD) and parafoveal macular thickness (PaMT) of the affected right eye at 2 months (a) and 3 months (b) with intravitreal SO, and at 5 months (c) and 6 months (d) after SO removal, and the corresponding en-face OCT images of the healthy fellow eye (e), (f), (g), and (h) respectively, are shown (a); SCPVD: 49.4, PaMT: 278 μm. (e); SCPVD: 57.0, PaMT: 329 μm. (b); SCPVD: 54.6, PaMT: 279 μm. (f); SCPVD: 57.5, PaMT: 332 μm. (c); SCPVD: 48.5, PaMT: 299 μm. (g); SCPVD: 52.2, PaMT: 326 μm. (d); SCPVD: 53.1, PaMT: 308 μm. (h); SCPVD: 57.0, PaMT: 332 μm
FAZ area and CCF measurements across follow-up visits are summarized in Tables 7 and 8. No statistically significant differences in FAZ area were observed within either study group or between study and control eyes at any time point (p > 0.05).
Table 7.
Distribution of FAZ area (mm2) measurements over time between study groups and control groups, and within each study group itself
| n | 2nd month | 3rd month | 5th month | 6th month | pd1 | |||
|---|---|---|---|---|---|---|---|---|
| FAZ (mm2) | Area (mm2) | C 3 F 8 | 13 | 0.25 ± 0.13 (0.11–0.53) | 0.24 ± 0.12 (0.11–0.51) | 0.25 ± 0.13 (0.11–0.50) | 0.25 ± 0.13 (0.11–0.51) | 0.313 |
| Control | 13 | 0.26 ± 0.12 (0.15–0.55) | 0.24 ± 0.09 (0.15–0.43) | 0.24 ± 0.10 (0.12–0.46) | 0.24 ± 0.09 (0.13–0.43) | 0.925 | ||
| p | 0.880 | 0.724 | 0.920 | 0.880 | ||||
| Area (mm2) | SO | 17 | 0.25 ± 0.08 (0.13–0.46) | 0.27 ± 0.10 (0.12–0.46) | 0.24 ± 0.07 (0.07–0.38) | 0.24 ± 0.07 (0.16–0.40) | 0.056 | |
| Control | 17 | 0.27 ± 0.08 (0.17–0.42) | 0.26 ± 0.08 (0.16–0.42) | 0.26 ± 0.08 (0.14–0.40) | 0.27 ± 0.08 (0.16–0.40) | 0.303 | ||
| p | 0.586 | 0.973 | 0.610 | 0.454 |
n: Number of eyes; Data are presented as “mean ± standard deviation (minimum-maximum)”; 1Friedman Test; 2Mann-Whitney U Test; FAZ: Foveal Avascular Zone; SO: Silicone Oil
Table 8.
Distribution of CCF measurements over time between study groups and control groups, and within each study group itself
| radius | n | 2nd month | 3rd month | 5th month | 6th month | pd1 | ||
|---|---|---|---|---|---|---|---|---|
| CCF | 1 mm | C 3 F 8 | 13 | 2.12 ± 0.14 (1.69–2.29) | 2.13 ± 0.12 (1.85–2.32) | 2.13 ± 0.13 (1.82–2.28) | 2.13 ± 0.12 (1.81–2.30) | 0.632 |
| Control | 13 | 2.20 ± 0.07 (2.05–2.34) | 2.18 ± 0.08 (1.98–2.34) | 2.18 ± 0.07 (2.06–2.32) | 2.17 ± 0.07 (2.05–2.29) | 0.225 | ||
| p | 0.113 | 0.186 | 0.311 | 0.418 | ||||
| 2 mm | C 3 F 8 | 13 | 8.76 ± 0.45 (7.42–9.32) | 8.83 ± 0.36 (8.03–9.47) | 8.86 ± 0.34 (7.93–9.19) | 8.79 ± 0.43 (7.64–9.36) | 0.542 | |
| Control | 13 | 8.96 ± 0.28 (8.38–9.35) | 8.90 ± 0.33 (8.00-9.35) | 8.96 ± 0.29 (8.30–9.36) | 8.98 ± 0.24 (8.39–9.29) | 0.894 | ||
| p | 0.169 | 0.362 | 0.479 | 0.223 | ||||
| 1 mm | SO | 17 | 2.12 ± 0.11 (1.97–2.32)cd | 2.09 ± 0.10 (1.96–2.29) | 2.05 ± 0.14 (1.66–2.26) | 2.03 ± 0.16 (1.59–2.20) | 0.002 | |
| Control | 17 | 2.15 ± 0.11 (1.94–2.31) | 2.14 ± 0.09 (1.98–2.35) | 2.14 ± 0.09 (1.96–2.33) | 2.13 ± 0.08 (1.97–2.30) | 0.849 | ||
| p | 0.433 | 0.131 | 0.073 | 0.049 | ||||
| 2 mm | SO | 17 | 8.78 ± 0.34 (8.17–9.46)cd | 8.70 ± 0.31 (7.97–9.17) | 8.48 ± 0.52 (7.67–9.26) | 8.40 ± 0.53 (7.05–9.07) | < 0.001 | |
| Control | 17 | 8.80 ± 0.38 (8.08–9.40) | 8.76 ± 0.33 (8.17–9.44) | 8.79 ± 0.32 (8.33–9.38) | 8.76 ± 0.27 (8.28–9.34) | 0.864 | ||
| p | 0.946 | 0.683 | 0.114 | 0.034 |
n: Number of eyes; Data are presented as “mean ± standard deviation (minimum-maximum)”; 1Friedman Test; 2Mann-Whitney U Test; aPost-hoc pairwise comparison showed a significant difference at “month 2”; bPost-hoc pairwise comparison showed a significant difference at “month 3”; cPost-hoc pairwise comparison showed a significant difference at “month 5”; dPost-hoc pairwise comparison showed a significant difference at “month 6”; CCF: Choriocapillary Flow; SO: Silicone Oil
Although lower CCF values within the 1-mm and 2-mm radius areas were observed in the C3F8 group compared with controls at all time points, these differences were not statistically significant (p > 0.05). In the SO group, CCF values within both the 1-mm and 2-mm radius areas were significantly lower at postoperative months 5 and 6 compared with month 2 (p < 0.002). Furthermore, CCF measurements at postoperative month 6 were significantly lower in the SO group than in healthy fellow eyes in both radius areas (p < 0.05).
Table 9 shows the distribution of BCVA, IOP, image quality, SCPVD, DCPVD, MT, FAZ area, and CCF values at 6 months postoperative among the study groups. Accordingly, at 6 months, BCVA, parafoveal SCPVD, parafoveal thickness, and CCF values in terms of LogMAR were found to be lower in the SO group compared to the C3F8 group; however, no significant differences were found between the groups in terms of IOP, FAZ area, foveal SCPVD, foveal DCPVP, foveal thickness, and parafoveal DCPVD values.
Table 9.
Distribution of BCVA, IOP, image quality, SCPVD, DCPVD, Macular thickness, FAZ area and CCF among study groups at 6 months
| 6.month | C3F8 (n = 13) | SO (n = 17) | p a | |
|---|---|---|---|---|
| Mean ± SD (min-max) | Mean ± SD (min-max) | |||
| BCVA (LogMAR) | 0.25 ± 0.21 (0-0.7) | 0.66 ± 0.26 (0.3–1.1) | < 0.001** | |
| IOP | 16.5 ± 2.5 (12–19) | 16.4 ± 2.4 (12–19) | 0.869 | |
| Scan quality | 7.9 ± 0.8 (7–9) | 7.1 ± 0.8 (6–8) | 0.022* | |
| SCPVD | Fovea | 23.9 ± 8.4 (10.6–36.0) | 21.3 ± 7.4 (7.6–39.2) | 0.563 |
| Parafovea | 50.9 ± 3.2 (45.3–56.1) | 44.3 ± 5.9 (34.1–54.8) | 0.001** | |
| DCPVD | Fovea | 36.5 ± 8.5 (20.4–50.0) | 34.7 ± 6.3 (22.0-46.4) | 0.408 |
| Parafovea | 52.9 ± 3.6 (49.0-60.5) | 51.5 ± 4.7 (43.4–60.1) | 0.408 | |
|
Macular Thickness |
Fovea | 258.7 ± 20.4 (233–285) | 239.5 ± 31.1 (177–293) | 0.132 |
| Parafovea | 326.5 ± 11.2 (307–346) | 304.7 ± 21.7 (270–340) | 0.006** | |
| FAZ | Area (mm 2 ) | 0.25 ± 0.13 (0.11–0.51) | 0.24 ± 0.07 (0.07–0.38) | 0.483 |
| CCF | 1 mm | 2.13 ± 0.12 (1.81–2.30) | 2.03 ± 0.16 (1.59–2.20) | 0.035* |
| 2 mm | 8.79 ± 0.43 (7.64–9.36) | 8.40 ± 0.53 (7.05–9.07) | 0.039* | |
n: Number of eyes; SD: Standard deviation; aMann-Whitney U Test; BCVA: Best Corrected Visual Acuity; IOP: Intraocular Pressure; SCPVD: Superficial Capillary Plexus Vessel Density; DCPVD: Deep Capillary Plexus Vessel Density; FAZ: Foveal Avascular Zone, CCF: Choriocapillary Flow; SO: Silicone Oil *p < 0.05; **p < 0.01
Table 10 shows the relationship between the differences in BCVA, CCF, and parafoveal SCPVD, MT, and DCPVD variables in the examined eyes at 2 and 6 months, according to the study groups. Accordingly, in the C3F8 group, a strong negative correlation was found between the change in parafoveal MT and the change in CCF (p < 0.05), while in the SO group, a strong negative correlation was found between the change in SCPVD and the change in BCVA (p < 0.05), and a strong positive correlation was found between the change in SCPVD and the change in DCPVD (p < 0.01).
Table 10.
The relationship between the 2nd-month and 6th-month value differences of the variables BCVA, CCF and parafoveal SCPVD, MT, DCPVD for the eyes examined according to study groups
| Group | (2.month-6.month) | (2. month-6.month) | |||||
|---|---|---|---|---|---|---|---|
| BCVA (LogMAR) | SCPVD | MT | DCPVD | CCF (1 mm) |
CCF (2 mm) |
||
| C3F8 (n = 13) | BCVA (LogMAR) | 1.000 | 0.055 | -0.338 | -0.349 | -0.281 | -0.080 |
| SCPVD | 0.055 | 1.000 | 0.064 | 0.129 | -0.388 | -0.231 | |
| MT | -0.338 | 0.064 | 1.000 | 0.253 | -0.660 * | -0.615 * | |
| DCPVD | -0.349 | 0.129 | 0.253 | 1.000 | -0.083 | -0.344 | |
| CCF (1 mm) | -0.281 | -0.388 | -0.660 * | -0.083 | 1.000 | 0.894 ** | |
| CCF (2 mm) | -0.080 | -0.231 | -0.615 * | -0.344 | 0.894 ** | 1.000 | |
| SO (n = 17) | BCVA (LogMAR) | 1.000 | -0.521 * | 0.025 | -0.261 | 0.119 | 0.259 |
| SCPVD | -0.521 * | 1.000 | 0.423 | 0.726 ** | -0.164 | -0.326 | |
| MT | 0.025 | 0.423 | 1.000 | 0.089 | -0.145 | -0.106 | |
| DCPVD | -0.261 | 0.726 ** | 0.089 | 1.000 | 0.077 | -0.056 | |
| CCF (1 mm) | 0.119 | -0.164 | -0.145 | 0.077 | 1.000 | 0.801 ** | |
| CCF (2 mm) | 0.259 | -0.326 | -0.106 | -0.056 | 0.801 ** | 1.000 | |
#Data are presented as “Spearman Correlation Coefficient”; BCVA: Best Corrected Visual Acuity; SCPVD: Superficial Capillary Plexus Vessel Density; MT: Macular Thickness; DCPVD: Deep Capillary Plexus Vessel Density; CCF: Choriocapillary Flow; SO: Silicone Oil *p < 0.05; **p < 0.01
Discussion
The macular perfusion system, comprising the superficial capillary plexus (SCP), deep capillary plexus (DCP), and the choriocapillaris, plays a critical role in meeting the metabolic demands of retinal neurons required for normal visual function [13]. Quantitative evaluation of capillary density provides an objective method for detecting flow alterations caused by physiological or pathological processes [14]. However, limited data exist regarding the dynamic changes in macular perfusion following surgery in eyes with rhegmatogenous retinal detachment (RRD) involving the macula. Previous studies have demonstrated reduced retinal blood flow in RRD eyes [15–17], and macular microcirculatory impairment has been reported even in cases without macular involvement [18, 19]. In the present study, we investigated postoperative macular perfusion changes in RRD eyes treated with either SO or C3F8 gas tamponade and compared these findings with those of healthy fellow eyes.
Wang et al. reported significantly reduced parafoveal SCPVD and DCPVD at 2, 4, and 8 weeks postoperatively, as well as decreased CCF density at weeks 2 and 4, in patients with macula-off RRD treated with intraocular gas tamponade [13]. They further demonstrated a gradual postoperative increase in SCP, DCP, and CCF densities, with diminishing differences compared to healthy eyes over time. Based on these findings, they described recovery curves for macular microcirculation, suggesting that CCF density reaches a plateau earlier (around 8 weeks) than SCPVD and DCPVD (approximately 12 weeks). In our study, no statistically significant differences were observed between the C3F8 group and the control group regarding parafoveal SCPVD or CCF measurements at any postoperative time point. These findings suggest that recovery of SCP and CCF may have been completed before the second postoperative month, or alternatively, that C3F8 gas does not exert a significant adverse effect on SCPVD or choriocapillaris perfusion in our study population. In contrast, parafoveal DCPVD was significantly reduced in the C3F8 group at the second and third postoperative months compared with healthy fellow eyes. Consistent with the findings of Wang et al. [13], DCPVD appeared to reach a plateau after the third month, with gradual reduction in the difference between RRD and control eyes over time. Additionally, parafoveal MT did not differ significantly between the C3F8 and control groups at any time point, in agreement with previous reports [13].
Woo et al. reported that retinal microvascular changes associated with RRD resemble those observed in retinal vein occlusion (RVO), particularly when C3F8 gas is used as a tamponade [20]. They suggested that perfusion impairment in RVO predominantly affects the DCP rather than the SCP, as the SCP is directly connected to retinal arterioles and maintains higher perfusion pressure, whereas the DCP consists mainly of venous collecting channels and is more susceptible to increases in venous pressure. Furthermore, retinal detachment may impede oxygen diffusion from the choriocapillaris to the DCP due to the presence of subretinal fluid. The DCP, located at the outer border of the inner nuclear layer, lies within a watershed zone characterized by relatively low oxygen tension, making it particularly vulnerable to ischemia. Our findings—showing preserved SCPVD and transiently reduced DCPVD in the C3F8 group—support these hypotheses and suggest that RRD-related microvascular alterations predominantly affect the DCP.
Woo et al. also demonstrated enlargement of the deep foveal avascular zone (FAZ) two months after surgery in macula-off RRD eyes treated with C3F8 tamponade [20]. Similarly, Wang et al. suggested that persistent hypoperfusion during the early postoperative period may contribute to FAZ enlargement [13]. In our study, however, FAZ area measurements did not differ significantly within the C3F8 group or compared with healthy controls at any time point. This discrepancy may be related to differences in FAZ measurement methodology, as the OCT-A software used in our study provided a single FAZ value encompassing all retinal vascular layers.
Alongside several studies evaluating gas tamponades using OCT-A [13, 20], despite concerns about the reliability of retinal vascular imaging [21, 22], OCT-A studies in the presence of SO have been increasing in recent years [21–24]. Christou et al. [21], in a review of studies involving RRD patients who underwent PPV using SO, noted that despite the existing literature, additional longitudinal studies are needed to characterize the long-term efficacy of SO in clinical practice.
Purtskhvanidze et al. reported significant thinning of the parafoveal ganglion cell layer and inner plexiform layer in eyes treated with SO compared with gas tamponade and healthy controls, attributing these findings to the potential toxic effects of SO [25]. Consistent with these observations, we found significantly reduced parafoveal SCPVD and MT in the SO group at all postoperative time points. These findings suggest that SO may exert a toxic effect on the parafoveal region, where the ganglion cell layer is most prominent.
Regarding cases treated with intravitreal SO, the literature generally reports adverse outcomes related to macular vascular density [22, 23]. Christou et al. [22] showed a decrease in macular (fovea, parafovea and perifovea) SCPVD and perfusion after repair with SO, while Roohipoor et al. [23] demonstrated a decrease in postoperative parafoveal SCPVD and total retinal vascular density in eyes treated with SO. The current study is consistent with previous studies, finding that SCPVD values in the parafoveal area were significantly lower in the SO group compared to the control group at all time points. Bayraktar et al. [26] examined macular-off RRD patients before and after SO extraction and found that all macular, foveal and parafoveal MT measurements were decreased compared to the other eyes and did not show improvement after SO extraction. Furthermore, all macular, foveal and parafoveal SCPVD measurements were lower than in the other eye after SO extraction [26]. The current study is similar to the study by Bayraktar et al. in that the SCPVD and MT measurements in the parafoveal area were found to be lower at all time points before and after SO extraction in the SO group compared to the control group.
Despite these structural and vascular changes, FAZ area measurements did not differ significantly between the SO group and controls at any follow-up visit. FAZ size has been shown to be highly sensitive to ischemic events and various retinal pathologies [27–32]. The absence of FAZ enlargement in our study may indicate that different tamponade agents do not induce overt macular ischemia in RRD eyes with macular involvement.
Previous studies evaluating choroidal changes after RRD surgery have yielded conflicting results. While Akkoyun et al. reported no significant changes in choroidal thickness following PPV with either gas or SO tamponade, Odrobina et al. observed significant subfoveal choroidal thinning at 3 and 6 months postoperatively in eyes treated with SO [33]. They suggested that SO may exert toxic effects on both retinal and choroidal structures, potentially mediated by reduced choroidal blood flow. Additional hypotheses propose that long-term SO tamponade disrupts normal ionic exchange between the retina and vitreous, impairing Müller cell function and potassium buffering [34]. Given the continuous ion and fluid exchange between the retina, retinal pigment epithelium, and choroid, modulation of this flow may influence choroidal thickness [35]. In accordance with these findings, we observed significantly reduced CCF values in the 1-mm and 2-mm radius areas in the SO group at the fifth and sixth postoperative months, following SO removal, compared with measurements obtained during SO tamponade. Furthermore, CCF values at six months were significantly lower in the SO group than in healthy fellow eyes. These results suggest that the negative effects of SO on chorioretinal circulation may persist even after its removal. Supporting this hypothesis, Karimi et al. reported sustained choroidal thinning in RRD eyes following prolonged SO tamponade, with continued thinning observed even after oil removal [36].
In a recent study, Ozal et al. [37] evaluated the effect of endotamponades on macular perfusion in macula-off RRD patients undergoing PPV using C3F8 or SO tamponade, and the patients’ own healthy fellow eyes were used as a control group, similar to the current study. While the authors found no difference in vascular density between the C3F8 group and the control group, they detected significantly lower VD values in the SCP, DCP, and choriocapillary plexus quadrants in the SO group compared to the control group [37]. The study by Ozal et al. [37] the current study show similarities in that in the C3F8 group, SCPVD and CCF values are similar to the control group, the FAZ area is similar in the study and control groups, and in the SO group, SCPVD and CCF values are lower compared to the control group. However, in the present study, a recovery curve in DCPVD was identified in the C3F8 group, while no effect on DCPVD was detected in the SO group. One reason for these differences may be that Ozal et al. performed OCT-A measurements at a single time point: at month 2 in the C3F8 group and at month 1 after SO extraction in the SO group. Another reason could be that the retinal areas being evaluated are different depending on the devices used for the measurements. Ozal et al. [37] performed SCPVD and DCPVD measurements from central, superior, inferior, temporal, and nasal regions, while in the present study, foveal and parafoveal SCPVD and DCPVD values were evaluated. Furthermore, while the present study detected lower parafoveal thickness values at all time points compared to the control group, which would explain the low SCPVD values thought to be caused by SO, no data regarding MT values were reported in the study by Ozal et al. [37].
Panretinal photocoagulation (PRP) has been associated with progressive reductions in subfoveal choroidal thickness and CCF [38, 39]. In the present study, laser photocoagulation was limited to areas surrounding retinal breaks and iatrogenic retinotomies, without diffuse PRP. Therefore, the observed CCF changes are unlikely to be attributable to laser treatment.
In the present study, no statistically significant difference was observed in foveal SCPVD and DCPVD within the study groups themselves or between the study groups and healthy fellow eyes at any follow-up visit. However, at months 2 and 3, foveal MT was measured to be significantly lower in the SO group compared to the control group. Regarding foveal VD, the results of previous studies have led to controversy [22, 23, 40, 41]. While some studies [22, 40] confirmed a decrease in foveal VD, others [23, 41] did not detect any significant change in the foveal capillary plexus. Christou et al. [22] attributed the absence of changes in foveal VD to the fovea being relatively devoid of vessels, and therefore it may be difficult to detect small changes. Furthermore, the contour of the foveal pit lies below the SO-retina interface, which may protect it from direct SO contact [23]. In our study groups, we did not find a significant difference in foveal VD compared to the control groups. This situation suggests that, apart from the mechanical effect of SO, foveal avascularity is preserved, and the decrease seen in parafoveal SCPVD, as opposed to the foveal region, is actually due to the negative effects of SO, distinct from macular-off RRD itself.
Despite physiological differences in the eyes between the study groups, as well as characteristics such as retinal tear, detachment location, and extent of detachment requiring different endotamponade uses, we performed an additional statistical analysis between the study groups at 6 months postoperatively. Accordingly, at 6 months, BCVA, parafoveal SCPVD, parafoveal thickness, and CCF values in terms of LogMAR were found to be lower in the SO group compared to the C3F8 group; however, no significant difference was found between the groups in terms of FAZ area, foveal SCPVD, foveal DCPVP, foveal thickness, and parafoveal DCPVD values. In their study evaluating macular-off RRD patients at 1 and 3 months postoperatively, Fang et al. [42] reported that parafoveal SCPVD and parafoveal MT were reduced in the SO group compared to patients who received air at both time points, while parafoveal DCPVD and FAZ area remained unchanged. The study by Fang et al. [42] is largely similar to the results of our current study between the C3F8 and SO groups at 6 months postoperatively.
Different studies have shown varying correlations between postoperative vascular density parameters and BCVA [43, 44]. Yui et al. [43] reported no correlation between BCVA and SCPVD values in the postoperative period, while Christou et al. [44] stated that BCVA showed a positive correlation with SCPVD in macular detachment patients who received gas tamponade and had a detachment duration of 11 to 30 days, but no correlation in those with a detachment duration of 0 to 10 days. Christou et al. [22] demonstrated that decreased SCP flow densities in each macular region after SO repair were associated with deterioration of BCVA at 1 month postoperatively. In the current study, while no correlation was found between changes in parafoveal vascular parameters and BCVA at 2 and 6 months post-surgery in the C3F8 group, where the mean detachment duration was 13.2 ± 8.8 days, a strong negative correlation was found between changes in parafoveal SCPVD and changes in BCVA in the SO group, similar to the study by Christou et al. [22]. Christou et al. [22] explain this by stating that the function of photoreceptors shows a significantly negative correlation with microcirculation in both the foveal and eccentric regions of the macula.
In addition to its prospective design, the evaluation of chorioretinal vascular parameters using sequential OCT-A scans at multiple time points with high image quality in both the C3F8 and SO groups, the assessment of the change in parameters of the study groups over time using correlation analysis, and the comparison of the parameters of the study groups with those of healthy fellow eyes constitute the strengths of this study. The relatively small sample size, the potential for type I error increase due to the examination of multiple parameters at different time points, and the lack of multivariate analysis are the main limitations of this study. Another limitation is that preoperative OCT-A measurements were not taken and the height or volume of the macular detachment was not measured. Furthermore, the observed decrease in SCPVD may be due not only to the effects of SO but also to the macular-off RRD itself. Some studies in the literature include patients without macular involvement in their designs to avoid this effect of retinal detachment [45–48]. However, as we have already mentioned [18, 19], even in retinal detachment without macular involvement, the role of retinal detachment itself in macular microcirculation disorders cannot be definitively ruled out.
In conclusion, our findings suggest that SO tamponade may lead to persistent reductions in MT, SCPVD, and CCF, even after successful anatomical repair and subsequent SO removal. In contrast, DCPVD demonstrated gradual recovery following C3F8 tamponade. These results support the hypothesis that SO exerts a toxic effect on both retinal structure and microvasculature. The optimal timing for SO removal remains unclear, and while our findings suggest that earlier removal may be possible to minimize long-term microvascular damage, it is uncertain which OCT-A parameter should be used to make this decision. Moreover, removing SO earlier may increase the risk of recurrent detachment. OCT-A provides a noninvasive and sensitive method for evaluating retinal and choroidal microcirculation following RRD surgery. Assessment of macular vessel density and CCF may aid in determining the optimal timing of SO removal and help explain variations in visual outcomes after surgery. Future studies with larger sample sizes and longer follow-up are needed to clarify the prognostic significance of OCT-A findings and to guide tamponade selection in RRD surgery.
Acknowledgements
None.
Author contributions
Conception: Mustafa Salih Karatepe, Yasemin Özdamar Erol Design: Mustafa Salih Karatepe, Yasemin Özdamar Erol Data collection: Mustafa Salih Karatepe Analysis/Interpretation: Mustafa Salih Karatepe, Yasemin Özdamar Erol Literature review: Mustafa Salih Karatepe Writer: Mustafa Salih Karatepe, Yasemin Özdamar Erol.
Funding
The authors received no financial support for the research, author-ship, and/or publication of this article.
Data availability
The data that support the findings of this study are available from the corresponding author, upon reasonable request.
Declarations
Ethics approval and consent to participate
The study was approved by the local ethics committee of Ankara Numune Training and Research Hospital at 29/11/2018 with the number E-18-2295 and adhered to the tenets outlined in the Declaration of Helsinki. Written and verbal informed consent was obtained from all patients.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Karacorlu M, Sayman Muslubas I, Hocaoglu M, et al. Correlation between morphological changes and functional outcomes of recent-onset macula-off rhegmatogenous retinal detachment: prognostic factors in rhegmatogenous retinal detachment. Int Ophthalmol. 2018;38:1275–83. [DOI] [PubMed] [Google Scholar]
- 2.Kubicka-Trzaska A, Kobylarz J, Romanowska-Dixon B. Macular microcirculation blood flow after pars plana vitrectomy with silicone oil tamponade. Klin Ocz. 2011;113:146–8. [PubMed] [Google Scholar]
- 3.Effert R, Wolf S, Arend O, et al. Retinal hemodynamics after pars plana vitrectomy with silicone oil tamponade. Ger J Ophthalmol. 1994;3:65–7. [PubMed] [Google Scholar]
- 4.Kur J, Newman EA, Chan-Ling T. Cellular and physiological mechanisms underlying blood flow regulation in the retina and choroid in health and disease. Prog Retin Eye Res. 2012;31:377–406. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Parver LM, Auker CR, Carpenter DO. The stabilizing effect of the choroidal circulation on the temperature environment of the macula. Retina. 1982;2:117–20. [DOI] [PubMed] [Google Scholar]
- 6.Caramoy A, Droege KM, Kirchhof B, Fauser S. Retinal layers measurements in healthy eyes and in eyes receiving silicone oil-based endotamponade. Acta Ophthalmol. 2014;92:292–7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Christensen UC, la Cour M. Visual loss after use of intraocular silicone oil associated with thinning of inner retinal layers. Acta Ophthalmol. 2012;90:733–7. [DOI] [PubMed] [Google Scholar]
- 8.Balaratnasingam C, Inoue M, Ahn S, et al. Visual Acuity Is Correlated with the Area of the Foveal Avascular Zone in Diabetic Retinopathy and Retinal Vein Occlusion. Ophthalmology. 2016;123:2352–67. [DOI] [PubMed] [Google Scholar]
- 9.Kim DY, Fingler J, Zawadzki RJ, et al. Noninvasive imaging of the foveal avascular zone with high-speed, phase-variance optical coherence tomography. Investig Ophthalmol Vis Sci. 2012;53:85–92. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Takase N, Nozaki M, Kato A, et al. Enlargement of foveal avascular zone in diabetic eyes evaluated by en face optical coherence tomography angiography. Retina. 2015;35:2377–83. [DOI] [PubMed] [Google Scholar]
- 11.Di G, Weihong Y, Xiao Z, et al. A morphological study of the foveal avascular zone in patients with diabetes mellitus using optical coherence tomography angiography. Graefes Arch Clin Exp Ophthalmol. 2016;254:873–9. [DOI] [PubMed] [Google Scholar]
- 12.Freiberg FJ, Pfau M, Wons J, et al. Optical coherence tomography angiography of the foveal avascular zone in diabetic retinopathy. Graefes Arch Clin Exp Ophthalmol. 2016;254:1051–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Wang H, Xu X, Sun X, et al. Macular perfusion changes assessed with optical coherence tomography angiography after vitrectomy for rhegmatogenous retinal detachment. Graefes Arch Clin Exp Ophthalmol. 2019;257:733–40. [DOI] [PubMed] [Google Scholar]
- 14.Chan G, Balaratnasingam C, Yu PK, et al. Quantitative changes in perifoveal capillary networks in patients with vascular comorbidities. Investig Ophthalmol Vis Sci. 2013;54:5175–85. [DOI] [PubMed] [Google Scholar]
- 15.Sato EA, Shinoda K, Kimura I, et al. Microcirculation in eyes after rhegmatogenous retinal detachment surgery. Curr Eye Res. 2007;32:773–9. [DOI] [PubMed] [Google Scholar]
- 16.Iwase T, Kobayashi M, Yamamoto K, et al. Changes in Blood Flow on Optic Nerve Head After Vitrectomy for Rhegmatogenous Retinal Detachment. Investig Ophthalmol Vis Sci. 2016;57:6223–33. [DOI] [PubMed] [Google Scholar]
- 17.Roldán-Pallarés M, Musa AS, Hernández-Montero J, et al. Retinal detachment and proliferative vitreoretinopathy: central retinal artery blood velocities, intraocular pressure, and endothelin 1. Retina. 2013;33:1528–39. [DOI] [PubMed] [Google Scholar]
- 18.Eshita T, Shinoda K, Kimura I, et al. Retinal blood flow in the macular area before and after scleral buckling procedures for rhegmatogenous retinal detachment without macular involvement. Jpn J Ophthalmol. 2004;48:358–63. [DOI] [PubMed] [Google Scholar]
- 19.Kubicka-Trzaska A, Górniak-Bednarz A. Macular microcirculation blood flow changes after conventional surgery for rhegmatogenous retinal detachment. Klin Oczna. 2007;109:179–82. [PubMed] [Google Scholar]
- 20.Woo JM, Yoon YS, Woo JE, Min JK. Foveal Avascular Zone Area Changes Analyzed Using OCT Angiography after Successful Rhegmatogenous Retinal Detachment Repair. Curr Eye Res. 2018;43:674–8. [DOI] [PubMed] [Google Scholar]
- 21.Christou EE, Papaconstantinou D, Droutsas K, et al. Effect of silicone oil on retinal microcirculation after vitrectomy for rhegmatogenous retinal detachment evaluated by OCT angiography: a literature review. Ther Adv Ophthalmol. 2023;15:25158414231174145. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Christou EE, Stavrakas P, Georgalas I, et al. Macular microcirculation changes after macula-off rhegmatogenous retinal detachment repair with silicone oil tamponade evaluated by OCT-A: preliminary results. Ther Adv Ophthalmol. 2022;14:25158414221105222. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Roohipoor R, Tayebi F, Riazi-Esfahani H, et al. Optical coherence tomography angiography changes in macula-off rhegmatogenous retinal detachments repaired with silicone oil. Int Ophthalmol. 2020;40:3295–302. [DOI] [PubMed] [Google Scholar]
- 24.Jiang J, Chen S, Jia YD, et al. Evaluation of macular vessel density changes after vitrectomy with silicone oil tamponade in patients with rhegmatogenous retinal detachment. Int J Ophthalmol. 2021;14:881–6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Purtskhvanidze K, Hillenkamp J, Tode J, et al. Thinning of Inner Retinal Layers after Vitrectomy with Silicone Oil versus Gas Endotamponade in Eyes with Macula-Off Retinal Detachment. Ophthalmologica. 2017;238:124–32. [DOI] [PubMed] [Google Scholar]
- 26.Bayraktar Z, Pehlivanoglu S, Hagverdiyeva S, et al. Longitudinal evaluation of retinal thickness and OCT-A parameters before and following silicone oil removal in eyes with macula-on and macula-off retinal detachments. Int Ophthalmol. 2022;42:1963–73. [DOI] [PubMed] [Google Scholar]
- 27.Samara WA, Say EA, Khoo CT, et al. CORRELATION OF FOVEAL AVASCULAR ZONE SIZE WITH FOVEAL MORPHOLOGY IN NORMAL EYES USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. Retina. 2015;35:2188–95. [DOI] [PubMed] [Google Scholar]
- 28.Conrath J, Giorgi R, Raccah D, Ridings B. Foveal avascular zone in diabetic retinopathy: quantitative vs qualitative assessment. Eye. 2005;19:322–6. [DOI] [PubMed] [Google Scholar]
- 29.Parodi MB, Visintin F, Della Rupe P, Ravalico G. Foveal avascular zone in macular branch retinal vein occlusion. Int Ophthalmol. 1995;19:25–8. [DOI] [PubMed] [Google Scholar]
- 30.Sanders RJ, Brown GC, Rosenstein RB, Magargal L. Foveal avascular zone diameter and sickle cell disease. Arch Ophthalmol. 1991;109:812–5. [DOI] [PubMed] [Google Scholar]
- 31.Mintz-Hittner HA, Knight-Nanan DM, Satriano DR, Kretzer FL. A small foveal avascular zone may be an historic mark of prematurity. Ophthalmology. 1999;106:1409–13. [DOI] [PubMed] [Google Scholar]
- 32.Dubis AM, Hansen BR, Cooper RF, et al. Relationship between the foveal avascular zone and foveal pit morphology. Investig Ophthalmol Vis Sci. 2012;53:1628–36. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.Odrobina D, Gołębiewska J, Maroszyńska I, CHOROIDAL THICKNESS CHANGES AFTER, VITRECTOMY WITH SILICONE OIL TAMPONADE FOR PROLIFERATIVE VITREORETINOPATHY RETINAL DETACHMENT. Retina. 2017;37:2124–9. [DOI] [PubMed] [Google Scholar]
- 34.Winter M, Eberhardt W, Scholz C, Reichenbach A. Failure of potassium siphoning by Müller cells: a new hypothesis of perfluorocarbon liquid-induced retinopathy. Investig Ophthalmol Vis Sci. 2000;41:256–61. [PubMed] [Google Scholar]
- 35.Nickla DL, Wallman J. The multifunctional choroid. Prog Retin Eye Res. 2010;29:144–68. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 36.Karimi S, Entezari M, Nikkhah H, et al. Effects of Intravitreal Silicone Oil on Subfoveal Choroidal Thickness. Ophthalmologica. 2018;239:159–66. [DOI] [PubMed] [Google Scholar]
- 37.Ozal E, Guler MS, Karapapak M, et al. BEYOND THE SURFACE: Investigating Silicone Oil’s Impact on Macular Perfusion in Macula-Off Rhegmatogenous Retinal Detachment by Optical Coherence Tomography Angiography. Retina. 2025;45:621–9. [DOI] [PubMed] [Google Scholar]
- 38.Stitt AW, Gardiner TA, Archer DB. Retinal and choroidal responses to panretinal photocoagulation: an ultrastructural perspective. Graefes Arch Clin Exp Ophthalmol. 1995;233:699–705. [DOI] [PubMed] [Google Scholar]
- 39.Zhang Z, Meng X, Wu Z, et al. Changes in Choroidal Thickness After Panretinal Photocoagulation for Diabetic Retinopathy: A 12-Week Longitudinal Study. Investig Ophthalmol Vis Sci. 2015;56:2631–8. [DOI] [PubMed] [Google Scholar]
- 40.Bonfiglio V, Ortisi E, Scollo D, et al. Vascular changes after vitrectomy for rhegmatogenous retinal detachment: optical coherence tomography angiography study. Acta Ophthalmol. 2020;98:e563–9. [DOI] [PubMed] [Google Scholar]
- 41.Tsen CL, Sheu SJ, Chen SC, Wu TT. Imaging analysis with optical coherence tomography angiography after primary repair of macula-off rhegmatogenous retinal detachment. Graefes Arch Clin Exp Ophthalmol. 2019;257:1847–55. [DOI] [PubMed] [Google Scholar]
- 42.Fang W, Zhai J, Mao JB, et al. A decrease in macular microvascular perfusion after retinal detachment repair with silicone oil. Int J Ophthalmol. 2021;14:875–80. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 43.Yui N, Kunikata H, Aizawa N, Nakazawa T. Optical coherence tomography angiography assessment of the macular capillary plexus after surgery for macula-off rhegmatogenous retinal detachment. Graefes Arch Clin Exp Ophthalmol. 2019;257:245–8. [DOI] [PubMed] [Google Scholar]
- 44.Christou EE, Kalogeropoulos C, Georgalas I, et al. Assessment of Anatomical and Functional Macular Changes with Optical Coherence Tomography Angiography After Macula-Off Rhegmatogenous Retinal Detachment Repair. Semin Ophthalmol. 2021;36:119–27. [DOI] [PubMed] [Google Scholar]
- 45.Lee JY, Kim JY, Lee SY, et al. Foveal Microvascular Structures in Eyes with Silicone Oil Tamponade for Rhegmatogenous Retinal Detachment: A Swept-source Optical Coherence Tomography Angiography Study. Sci Rep. 2020;10:2555. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 46.Lee J, Cho H, Kang M, Hong R, Seong M, Shin Y. Retinal Changes before and after Silicone Oil Removal in Eyes with Rhegmatogenous Retinal Detachment Using Swept-Source Optical Coherence Tomography. J Clin Med. 2021;10:5436. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 47.Liu Y, Lei B, Jiang R, et al. Changes of macular vessel density and thickness in gas and silicone oil tamponades after vitrectomy for macula-on rhegmatogenous retinal detachment. BMC Ophthalmol. 2021;21:392. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 48.Zhou Y, Zhang S, Zhou H, Gao M, Liu H, Sun X. Comparison of fundus changes following silicone oil and sterilized air tamponade for macular-on retinal detachment patients. BMC Ophthalmol. 2020;20:249. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data that support the findings of this study are available from the corresponding author, upon reasonable request.