Modified inverted internal limiting membrane flap technique for lamellar macular hole

Abstract

Background

Lamellar macular hole (LMH) is a partial-thickness macular defect thought to be caused by vitreofoveal traction, anteroposterior and tangential forces exerting traction on the fovea.

Methods

This is a retrospective study involving 19 eyes. 25-gauge pars plana vitrectomy (PPV), fovea sparing internal limiting membrane (ILM) peeling combined with modified inverted ILM flap under air for treatment of LMH was used.

Results

The study comprised 14 females and 5 males, involving 13 right and 6 left eyes, with a mean age of 69.52 ± 8.13 years. Symptom duration averaged 498.94 ± 646.96 days. The preoperative residual foveal thickness, which initially averaged 62.26 ± 46.21 μm, increased to a post-operative central foveal thickness of 85.05 ± 48.11 μm after 6 months. Foveal configuration was improved in 15 of 19 eyes (78.94%), one patient had persistent macular edema, and 3 eyes had irregular foveal contour. Among 19 eyes examined, 13 eyes (68.42%) showed intact external limiting membrane (ELM) and ellipsoid zone (EZ) lines both before and after the surgery, resulting in a smooth restoration of the foveal contour. Conversely, in 6 eyes (31.57%) assessed before the operation, the ELM and EZ lines were disrupted. Of these, 3 eyes (15.78%) exhibited improvement, while in the remaining 3 eyes (15.78%), the ELM and EZ lines remained disrupted even after 6 months of follow-up. The mean pre-operative best corrected visual acuity (BCVA) in LogMAR was 0.66 ± 0.43 and the mean post-operative BCVA in LogMAR at 1 months was 0.55 ± 0.24, at 3 months was 0.53 ± 0.25 and at 6 months was 0.51 ± 0.24, indicating an overall improvement in BCVA compared to pre-operative levels. Mean BCVA improved from 0.66 ± 0.43 logMAR pre-operative to 0.51 ± 0.24 logMAR at 6 months post-operatively (p = 0.058). There were no instances of full thickness macular hole and no foveal detachment.

Conclusion

PPV with fovea sparing ILM peeling combined with modified inverted ILM flap under air results in good morphological and functional outcomes.

Trial registration

The study project registration number (Tongji Hospital affiliated with Tongji University School of Medicine (Number: K-W-2024-001)).

Background

A lamellar macular hole (LMH) is a partial-thickness macular defect characterized by an irregular foveal contour that disturbs the inner retinal layers while largely sparing the outer retina. LMHs are commonly classified as degenerative lamellar macular hole (DLMH) or tractional lamellar macular hole (TLMH). DLMH typically shows a round-edged intraretinal cavitation and is often accompanied by epiretinal proliferation (EP), also referred to as lamellar hole–associated epiretinal proliferation (LHEP). T LMH displays a sharp-edged, schisis-like separation between retinal layers and usually lacks EP [1]. Over the last five years, (internal limiting membrane) ILM-flap–based approaches have shown consistent anatomic and functional gains in LMH. Mechanistic evidence from idiopathic macular hole demonstrates that a modified inverted ILM flap can achieve substantial visual improvement with ~ 98% closure, supporting flap-stabilizing strategies relevant to LMH [2]. In LMH cohorts, a single-layer flap stabilized with an ophthalmic viscoelastic improved BCVA and central thickness with no postoperative full thickness macular hole (FTMH) on short-term follow-up [3]. LHEP-embedding techniques (embedding EP within the cleft and covering it with an inverted flap) produced BCVA gains, thicker postoperative foveas, and resolution of outer-retinal defects, and outperformed conventional ILM peeling in comparative series [4–6]. A double-inverted flap further improved vision and eliminated postoperative FTMH compared with standard peeling [7]. Complementary microperimetry/FAF studies show increased retinal sensitivity and reduced hyper-autofluorescence after flap surgery, aligning structural recovery with functional improvement [8]. These findings sit within broader evidence that observed LMH eyes tend to decline slowly while selected patients benefit from surgery [9]; that OCT-based volumetric and outer-retinal biomarkers correlate with postoperative vision and can aid timing of intervention [10]; and that multicenter data describe contemporary outcomes and technique heterogeneity [11]. Recent reviews synthesize these advances and emphasize the value of fovea-sparing peeling, inverted flaps, and LHEP-embedding over wide peeling in appropriately selected eyes [12]; early comparative work continues to refine technique selection and underscores the need for adequately powered prospective trials [13].

Rationale and purpose of study

Given the heterogeneity of LMH subtypes and the risk of postoperative FTMH with conventional ILM peeling, we used a modified inverted ILM flap technique for LMH. During fluid–air exchange, a mobilized flap can be inadvertently displaced or aspirated, risking suboptimal foveal coverage. Our modification combines fovea-sparing ILM peeling with a trimmed, “petaloid” inverted ILM flap that is positioned and embedded under air to enhance flap stability and coverage while minimizing foveal manipulation. We hypothesized that this approach would promote tissue regeneration, restore foveal contour, and improve visual acuity while minimizing the risk of FTMH. The objectives were to evaluate anatomic (foveal contour, outer-retinal layer status) and functional (BCVA) outcomes of the modified technique for LMH, document complications over 6 months, and compare our outcomes with recently described techniques and identify factors associated with postoperative visual improvement.

Materials and methods

Study population

This is a retrospective study with a total of 19 patients who were operated for LMH surgery in our hospital from January 2022 to November 2023. The Research Ethics Committee of Tongji Hospital affiliated with Tongji University School of Medicine approved the retrospective review of the patients’ data. Informed consent was obtained from all patients. The study was conducted in accordance with the Declaration of Helsinki. The inclusion criteria were a symptomatic patient with a confirmed diagnosis of LMH, a follow up period of 6 months, a patient with progressive or disabling visual loss, symptomatic patients complaining of disturbing metamorphopsia, and in OCT there are signs of anatomical progression, like a reduction in central macular thickness or an enlargement of the LMH and an increase in ellipsoid zone disruption. Exclusion criteria were patients who had incomplete medical records, eyes with other macular pathologies, glaucoma, uveitis, intraocular infections, retinal vascular diseases, corneal scarring, trauma and history of prior ophthalmic surgery except cataract surgery. Baseline demographic data, including age, sex, duration of LMH, slit-lamp biomicroscopy, intraocular pressure measurement (IOP), lens clarity evaluation, indirect ophthalmoscopy, preoperative and postoperative best corrected visual acuity (BCVA), and optical coherence tomography (OCT) (Zeiss cirrus, HD-OCT, model- 5000), were recorded for clinical analysis of patients. LMH was classified into different subtypes as described by Govetto et al. [1] into DLMH and TLMH. Among all the 19 eyes included in the study, 5 (26.31%) exhibited degenerative, and 14 (73.68%) exhibited tractional. Epiretinal proliferation (EP) was noted in 5 of 19 eyes (26.31%), all of which belonged to the degenerative LMH group. The diameter of LMH were measured using the OCT caliper function. The vertical thickness of the fovea was measured at the distance between the thinnest point of the fovea and the inner surface of the retinal pigment epithelium, namely residual foveal thickness (RFT). On horizontal OCT scans, two horizontal diameters were taken: the minimum horizontal diameter (MHD 1) is the distance between the edges of the hole at the level of the internal limiting membrane and the maximum horizontal diameter (MHD 2) at the mid-retinal level. Structural worsening was defined as the development of foveal detachment (FD) or full thickness macular hole (FTMH).

Surgical procedure

All the surgeries using this modified technique were performed by a single experienced surgeon, Dr. Bi Y. In cases with significant lens opacity that impaired fundus visualization during vitrectomy, simultaneous small incision phacoemulsification cataract surgery with intraocular lens implantation was performed prior to the vitrectomy in 14 patients. A 25-gauge transconjunctival microincision vitrectomy surgery using the Alcon Constellation Vision System was utilized. Retrobulbar anesthesia was administered (2% lidocaine mixed with 0.75% bupivacaine). Following standard pars plana core vitrectomy, completion of PVD induction with posterior hyaloid dissection and peripheral vitrectomy with vitreous base shaving was done, the ILM was identified using brilliant blue G dye applied for 20s. Initially, ILM peeling was performed in the peri-foveal area with widened internal limiting membrane peeling in all directions (temporal, upper and lower vascular arcades) followed by fovea-sparing ILM peeling centripetally raising an ILM flap in a 360-degree, while still attachment to the macular hole rim, approximately 200 μm around the fovea. The elevated ILM flap was trimmed using a vitrectomy cutter to reduce its size, thus forming a petaloid-shaped ILM; we have termed this technique as the ‘petaloid technique’. For the management of EP, these EP tissues were carefully embedded along with the ILM flap in a controlled manner. The surgical approach did not require additional manipulation beyond trimming and embedding. Then fluid -air exchange was performed. During the fluid-air exchange, the vitrectomy cutter was initially used to quickly lower the fluid level, followed by a flute needle which was used to slowly remove the fluid covering the macula. The needle’s tip was first positioned at the perifoveal area and kept away from the ILM flap to avoid mis-suction of the ILM. As the air plane reached the ILM flap, the flap was compressed and expanded by the air, allowing it to return to its original position. Throughout this process, the flute needle’s tip should be placed at the center of the macular hole to completely remove the residual fluid. Finally, using a soft silicone-tipped draining flute needle, the ILM flap was embedded within the retinal cleavage of the LMH to cover the center of the macular hole. Air pressure was lowered to about 15mmHg to prevent risk of ILM mis-aspiration. Figure 1 summarizes the surgical steps. The whole process was assisted by Intraoperative OCT. Figure 2 Intraoperative OCT showing the inverted ILM flap position. Sterilized air tamponade was used for all 19 eyes. The surgery was then completed by closing the scleral incision, and immediately following surgery, the patient’s head was positioned to a lateral position, and instructing to avoid lying flat and facing up for 1-week post-surgery to maintain ILM position in the center and to prevent fluid accumulation in the macular area. Along with routine post-operative follow-up examination of BCVA, IOP and slit-lamp evaluation, OCT examination was repeated at 1 month, 3 months and 6 months periods. No intraoperative and postoperative complication were observed.

Fig. 1.

Schematic presentation of intra operative steps of fovea-sparing ILM peeling combined with modified inverted ILM flap under air for the treatment of LMH. A. ILM flap was raised for peeling. B. ILM peeling was done in perifovea area in all directions up to the upper and lower vascular arcades extending temporal area. C. Fovea sparing ILM peeling was done centripetally toward the macula with intraocular forceps and left attached to the edge of the LMH. D. The raised ILM flap was trimmed to fit the size of the macular hole in a petaloid shape. Figure on right side is i-OCT view, dotted line represents air level. E. After fluid air exchange remaining ILM flap was plugged in the MH under air as shown by arrow. In figure (D) and (E) arrows indicate inverting of ILM into the MH so that the ILM completely covered the MH

Fig. 2.

2a. Intraoperative OCT taken post fluid-air exchange that clearly show the inverted ILM flap positioned over the LMH and the foveal contour following this modified technique. 2b. Final placement of the ILM flap embedded within the foveal defect

The primary outcome measures were to evaluate the postoperative morphological efficacy of the procedure using OCT, to assess improvements in foveal contour and central foveal thickness (CFT). The secondary outcomes measures were changes in BCVA, status of outer retinal layers (external limiting membrane-ELM; ellipsoid zone-EZ) and the occurrence of any complications.

Statistical analysis

All statistical analyses were performed using SPSS version 28.0 (SPSS Inc., Chicago, IL, USA). Changes in clinical parameters between enrollment and final follow-up were evaluated using a paired t-test to compare preoperative and postoperative changes in BCVA. All parameters used in the study were expressed as continuous variables shown as mean ± standard deviation (SD) and categorical variables as percentage. A p-value of less than 0.05 was considered significant. Visual acuity was recorded as decimal values and converted to the logarithm of the minimal angle of resolution (logMAR) units for statistical analysis and non-numeric values were changed as follows: count fingers = 1.7 Log MAR, hand movement = 2.0 LogMAR, light perception = 2.3 LogMAR, and no light perception = 3.0 Log MAR [14].

Results

There were 14 female and 5 males. Right eye was involved in 13 eyes and left eye in 6 eyes with a mean age of 69.52 ± 8.13 years. The mean duration of symptoms was 498.94 ± 646.96 days. Mean axial length was 23.9 ± 1.4 mm. Clinical characteristics of all 19 patients are summarized in Table 1. With the mean MHD 1 being 329.42 ± 293.67 μm, and the MHD 2 being 539.63 ± 515.16 μm. The mean pre-operative BCVA in LogMAR was 0.66 ± 0.43 and post-operative BCVA in LogMAR was 1.32 ± 0.64, indicating a temporary decrease in visual acuity immediately after surgery. However, the mean post-operative BCVA in LogMAR at 1 months was 0.55 ± 0.24, at 3 months was 0.53 ± 0.25 and at 6 months was 0.51 ± 0.24, demonstrating an overall enhancement in visual acuity compared to pre-operative levels. The mean BCVA improved from 0.66 ± 0.43 logMAR pre-operative to 0.51 ± 0.24 logMAR at 6 months post-operatively (p = 0.058) (Table 2). A subgroup analysis was performed to assess the anatomical progression. Subgroup analysis revealed that in cases of TLMH, the preoperative LogMAR was 0.65 ± 0.43, and at 6 months postoperatively, it was 0.49 ± 0.26. In contrast, for cases of DLMH, the preoperative LogMAR was 0.72 ± 0.54, and at 6 months postoperatively, it was 0.58 ± 0.17. Subgroup analysis showed that BCVA improved in TLMH (Table 3).

Table 1.

Demographics of 19 patients with LMH

Variables Mean ± SD (Percentage)
Age(years)	69.52 ± 8.13
Gender (%)
Male	5 (26.31%)
Female	14 (73.68%)
Laterality (%)
Right	13 (68.42%)
Left	6 (31.57%)
Disease duration (days)	498.94 ± 646.96 (60-2160)
Surgical procedure
PPV + Phaco + IOL	14
PPV	5
Tamponade
Air	19
MH1	329.42 ± 293.67 μm
MH2	539.63 ± 515.16 μm
Pre-op RFT	62.26 ± 46.21 μm
Post-op CFT	85.05 ± 48.11 μm

SD standard deviation, PPV pars plana vitrectomy, Phaco + IOL phacoemulsification with intraocular lens, MHD 1 Minimum horizontal diameter, MHD 2 Maximum horizontal diameter, RFT residual foveal thickness, CFT central foveal thickness, Pre-op  Pre-operative Post-op Post-operative

Table 2.

VA and IOP preoperative and postoperative for LMH

Variables	Pre-op	Post-op	Post-op1m	Post-op3m	Post-op6m
IOP	14.57±3.20 (11-22)	14.36±2.13 (13-27)	-	-	-
LogMAR	0.66±0.43 (0.40-2.0)	1.32±0.64 (0.10-2.0)	0.55±0.24 (0.10-2.0)	0.53±0.25* (0.10-2.0)	0.51±0.24** (0.10-1.6)

IOP intraocular pressure, LogMAR logarithm of the minimum angle of resolution, Pre-op Pre-operative, Post-opPost-operative, 1 m 1 month, 3 m 3 month, 6 m 6 month

*P < 0.05

**P < 0.01

Table 3.

Preoperative and postoperative LogMAR for types of LMH

Types of LMH	Pre-op LogMAR	Post-op LogMAR	Post-op1m LogMAR	Post-op3m LogMAR	Post-op6m LogMAR
DLMH	0.72 ± 0.54	1.5 ± 0.62	0.62 ± 0.23	0.62 ± 0.23	0.58 ± 0.17
TLMH	0.65 ± 0.43	1.25 ± 0.68	0.52 ± 0.26	0.5 ± 0.26	0.49 ± 0.26

LMH lamellar macular hole, DLMH degenerative lamellar macular hole, TLMH tractional lamellar macular hole, LogMAR logarithm of the minimum angle of resolution, Pre-op Pre-operative, Post-op Post-operative, 1 m 1 month, 3 m 3 month, 6 m 6 month

“Sample size and power” -“This was a retrospective case series; therefore, no a-priori sample size calculation was performed. Based on the observed paired change in BCVA (logMAR) from 0.66 ± 0.43 pre-operative to 0.51 ± 0.24 at 6 months (p = 0.058), we estimated the SD of paired differences as 0.323. Using a two-sided α = 0.05 and 80% power for a paired t-test, detecting a 0.15-logMAR improvement would require n ≈ 37 eyes; for 0.20 logMAR, n ≈ 21 eyes. With the present n = 19 eyes, the power to detect a 0.15-logMAR improvement is ~ 53%, and the minimum detectable difference at 80% power is ~ 0.21 logMAR.”

Normalization of foveal contour

Regarding normalization of foveal contour, foveal configuration was improved in 15 of 19 eyes (78.94%), one patient had persistent macular edema, and three patients had irregular foveal contour. Among 19 eyes examined, 13 eyes (68.42%) showed intact ELM and EZ lines both before and after the surgery, resulting in a smooth restoration of the foveal contour. Conversely, in 6 eyes (31.57%) assessed before the operation, the ELM and EZ lines were disrupted. Of these, 3 eyes (15.78%) exhibited improvement post-operatively, while in the remaining 3 eyes (15.78%), the ELM and EZ lines remained disrupted even after 6 months of follow-up. Overall, the postoperative presence of ELM and EZ was seen in 16 eyes (84.21%). The preoperative RFT, which initially was 62.26 ± 46.21 μm, increased to a post-operative CFT of 85.05 ± 48.11 μm after 6 months. In Fig. 3a, preoperative OCT images on left side (a, c, e, g) and post-operative OCT images on right side (b, d, f, h) of LMH. LMH with intra-retinal cysts and 6 months post-surgery with covered foveal cleavage showing regular foveal contour with outer retinal layers noted to be improved from baseline to final examination. While in Fig. 3b, preoperative OCT images on left side (a, c) and post-operative OCT images on right side (b, d) of LMH. (a, c) LMH with subfoveal discontinuous ELM & EZ layers and 6 months post-surgery with irregular foveal contour and outer retinal layers noted to be improved (ELM and EZ). There was arrested progression of LMH in all patients at 6 months follow-up. Postoperatively, there were no instances of FTMH formation and no FD. There was no intraoperative and postoperative complication seen at the 6 months follow-up.

Fig. 3.

3a. Preoperative OCT images on the left side (a- TLMH, c-TLMH,e- DLMH, g- TLMH) and postoperative OCT images on the right side (b, d, f, h) of LMH. LMH with intra-retinal cysts and 6 months post-surgery with covered foveal cleavage showing regular foveal contour with outer retinal layers noted to be improved from baseline to final examination. Note- tractional lamellar macular hole (TLMH) and degenerative lamellar macular hole (DLMH). 3b. Preoperative OCT images on the left side (a- TLMH, c- DLMH) and postoperative OCT images on the right side (b, d) of LMH. (a, c) LMH with subfoveal discontinuous external limiting membrane (ELM) & ellipsoid zone (EZ) layers and 6 months post-surgery with irregular foveal contour and outer retinal layers noted to be improved (ELM, EZ). Note- tractional lamellar macular hole (TLMH) and degenerative lamellar macular hole (DLMH)

Discussion

LMH is not a stable condition, but it tends to worsen over time. Although the natural evolution of LMH appears to be slow, in many studies a significant improvement in visual acuity after surgery has been observed. The results of this study indicate that the modified inverted ILM flap technique offers promising outcomes for LMH patients, enhancing both anatomical and functional recovery. These findings align with those of Shiode et al. [15] who demonstrated the effectiveness of combining the lamellar hole-associated epiretinal proliferation (LHEP) embedding technique with ILM inversion for the treatment of degenerative LMH with LHEP where they had used ILM inversion from upper macula only. Unlike Shiode et al., who utilized 1% sodium hyaluronate-chondroitin sulfate to stabilize the ILM flap, our technique employs a soft-tip cannula under air, thus eliminating the need for such additives and simplifying the procedure. Kumar K et al. [5] also did not require additional substances when they created multiple flaps of both LHEP and surrounding ILM using a soft-tip cannula during the fluid–air exchange. Previous techniques involving full ILM peeling have raised concerns, as studies like that by Bringmann A et al. [16] associate conventional ILM peeling with potential degenerative changes in the macula. Such techniques have been linked to the formation of degenerative lamellar holes following surgical treatment of tractional lamellar holes or FTMH, potentially leading to irregular regeneration without photoreceptors at the center of the fovea. In contrast, our modified approach leaves the ILM partially attached and repositions it, which may reduce the risk of iatrogenic trauma. This technique mirrors the findings of Shimada et al. [17]and Michaleswka et al. [18], who observed reduced iatrogenic damage when peeling around the fovea was avoided. Our method utilizes the residual ILM as a scaffold to promote Müller cell proliferation and growth factor release, aiding in the closure of MH. Moreover, our subgroup analysis revealed significant improvements in visual acuity among patients with tractional LMH compared to those with degenerative types, suggesting that the LMH subtype can significantly influence surgical outcomes. Such differential responses to surgery depending on LMH subtype have been noted by Govetto et al. [1], emphasizing on the necessity of tailoring surgical approaches to the specific pathology to optimize results. The limited number of cases, especially within subgroups of LMH types, restricts definitive conclusions regarding differences in visual or anatomical outcomes. The observed trends should be interpreted cautiously, and larger prospective studies are necessary to validate these findings. We emphasize that our subgroup analyses are exploratory and hypothesis-generating rather than definitive.

Similarly, studies by, Pang et al. [19] they compared LMH with LHEP and LMH with conventional ERM, where only one eye progressed to FTMH. While Compera et al. [20] reported a case of LMH with LHEP that progressed to FTMH. And Dell’ Omo et al. [21] analyzed LMH, with standard ERM alone in the follow-up period, they noticed the LHEP group progressed to FTMH. These studies highlighted the varying progression rates to iatrogenic FTMH or disruption of the photoreceptor layer [22] across different LMH treatments, reaffirming the inherent risks of conventional methods. And these complications of vitrectomy appear to be more frequent in patients with degenerative lamellar holes [23]. Notably, our study recorded no instances of FTMH development within a six-month follow-up. The improvements in BCVA and central retinal thickness observed in our study parallel those reported by Takahashi et al. [4], with significant recovery of the ELM and EZ integrity in 15.78% of cases post-operatively.

Current literature indicates that release of epiretinal traction alone has been shown to improve anatomical outcomes in tractional LMH [24]. The inverted ILM flap serves as a scaffold to facilitate Müller cell proliferation and potentially enhance foveal structural recovery, as supported by recent studies [25, 26]. Furthermore, these techniques may provide additional benefits in terms of anatomical stability and the restoration of outer retinal layers, especially in cases with residual or recurrent defects. Our findings suggest that this approach may improve the likelihood of foveal contour normalization, although further comparative studies are needed.”

The modifications presented in our study have certain advantages, particularly regarding the position of the ILM flap lying over the LMH at the end of the surgery since it was done under air. Post-surgery OCT examination and follow-up visits confirmed that the ILM was lying over the fovea. Fovea sparing ILM peeling was performed; hence, the residual ILM left around the fovea helps create support for the proliferation of Müller cells and the release of growth factors, which aid in the closure of the LMH. The migration of the ILM into the hole facilitated tissue bridging and healing, resulting in the restoration of the macular hole anatomy. Surgically repaired lamellar macular holes show improved foveal anatomy compared to the preoperative period, due to successful relief of tangential traction and the integration of the ILM as a bridging tissue. Subjective metamorphopsia was reduced postoperatively in all cases. Our study presents two key findings: firstly, there was a notable enhancement in the foveal architecture with anatomical restoration and partial recovery of the outer retinal layers, halting disease progression; secondly, the data indicates a functional enhancement in visual acuity.

Despite some limitations, including its retrospective design, small sample size, and short follow-up period, our study supports the efficacy of PPV with fovea sparing ILM peeling combined with a modified inverted ILM flap under air in improving both anatomical and functional outcomes after surgery. However, to more definitively determine the advantages of this approach, further prospective studies with larger cohorts and longer follow-up periods are necessary. These studies should aim to confirm our findings and possibly compare the modified technique directly with other recent innovations in the management of LMH to establish a more comprehensive treatment protocol. The classification of LMH into ‘tractional’ and ‘degenerative’ types used herein predates current nomenclature. While this categorization was appropriate at the time of our study, future research employing updated classification schemes may facilitate improved comparability and understanding of LMH subtypes.

Conclusions

The observed improvements in both visual acuity and foveal configuration from using the modified inverted ILM flap technique provide encouraging evidence of its potential benefits. The fovea-sparing approach seems particularly advantageous, supporting the proliferation of Müller cells and the release of growth factors, which are essential for the healing and closure of macular holes. These results highlight a significant step forward in the surgical management of lamellar macular holes, offering a potential enhancement over traditional methods that involve the complete removal of the ILM. This study contributes to the evolving field of retinal surgeries and underscores the importance of continued innovation and refinement of surgical techniques to further reduce the risks associated with LMH surgery.

Abbreviations

LMH

Lamellar macular hole

PPV

Pars plana vitrectomy

ILM

Internal limiting membrane

ELM

External limiting membrane

EZ

Ellipsoid zone

BCVA

Best corrected visual acuity

DLMH

Degenerative lamellar macular hole

TLMH

Tractional lamellar macular hole

EP

Epiretinal proliferation

ERM

Epiretinal membrane

IOP

Intraocular pressure measurement

BCVA

Best corrected visual acuity

OCT

Optical coherence tomography

RFT

Residual foveal thickness

MHD 1

Minimum horizontal diameter

MHD 2

Maximum horizontal diameter

FD

Foveal detachment

FTMH

Full thickness macular hole

CFT

Central foveal thickness

LHEP

Lamellar hole-associated epiretinal proliferation

Authors’ contributions

Designed the research study; KK, LB, BY. KK and BY performed the research; YS, LC and TZ collected and analyzed the data. KK has been involved in drafting the manuscript and all authors have been involved in revising it critically for important intellectual content. All authors give final approval of the version to be published. All authors have participated sufficiently in the work to take public responsibility for appropriate portions of the content and agreed to be accountable for all aspects of the work in ensuring that questions related to its accuracy.

Funding

This study was supported by grants by Shanghai Shenkang Hospital Development Center’s second round of “Three-year Action Plan to Promote Clinical Skills and Clinical Innovation in Municipal Hospitals (2022–2024)” demonstration research physician innovation transformation ability training program. Project ID: SHDC2022CD008, 2021 Key Clinical Research Project of Tongji Hospital (Project No.: ITJ (ZD) 2101).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

This study was approved by the Ethics Committee of the Tongji Hospital affiliated with Tongji University School of Medicine (Number: K-W-2024-001). Informed consent was obtained from all patients. The study was conducted in accordance with the Declaration of Helsinki.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.