Retinal pigment epithelial disruption after retinal detachment repair using perfluorocarbon liquid and gas tamponade: a case series

Abstract

Purpose

To describe two cases of central visual disturbances following uncomplicated pars plana vitrectomy for macula-on retinal detachment.

Observations

Both patients exhibited a distinctive angled pattern of focal disruptions of the retinal pigment epithelium, observed through fundus autofluorescence and optical coherence tomography. These changes were noted after surgery and remained stable over a 1.5-year follow-up period without any treatment. The pattern of the lesions suggests a mechanical etiology, potentially related to intraocular pressure fluctuations or the use of perfluorocarbon liquid during surgery.

Conclusions and importance

This two-case report highlights a distinct post-surgical macular retinal pigment epithelium disruption following vitrectomy for retinal detachment.

1. Introduction

Retinal detachment repair by pars plana vitrectomy is a commonly performed procedure in vitreoretinal practice. Heavy carbon liquids such as perfluorocarbon liquids (PFCL) are used to facilitate surgery in a variety of vitreoretinal indications.^1,2 They are useful for flattening and stabilizing the retina in more extensive and complex retinal detachments due to the high specific gravity.^1,2 While mechanical retinal displacement is a known phenomenon after retinal detachment repair,³ we report two cases with an additional pattern of postoperative retinal pigment epithelial (RPE) disruption. This report was written in compliance with the ethical standards of the 1964 Declaration of Helsinki and later amendments. Patients gave their consent for the use of clinical data and images for academic and research purposes.

1.1. Case 1

A 54-year-old man presented to our clinic with a superotemporal macula-sparing rhegmatogenous retinal detachment in the left eye. Central visual function was not affected (vision 20/20 Snellen). Relevant medical history included a mild blunt trauma without ocular damage in the same eye one year earlier.

Combined cataract surgery and chandelier-assisted pars plana vitrectomy was performed the next day. Vitreous was stained with triamcinolone acetonide. Decalin (DK-line®, Bausch + Lomb), a PFCL, was injected over the nasal peripapillary sector for stabilization of the retina and drainage of the subretinal fluid. Infusion fluid contained low, non-toxic doses of gentamicin (2 mg in 0.05 mL) and adrenalin (1 mg in 1 mL) in 500 mL balanced salt solution (BSS, Bausch + Lomb). After shaving of the vitreous base with scleral depression, 360° peripheral photocoagulation was performed, followed by fluid-air exchange, gas tamponade (SF6, 20 % in air) and suturing of the sclerotomies. Additional gas was injected with a 30-gauge needle to restore the ocular pressure, and peribulbar steroids were given at the end of the surgery. Postoperatively, positioning on the right side for one week was advised.

Two weeks after surgery, after clearance of the central gas tamponade, central visual impairment and metamorphopsia were noticed by the patient. Best corrected visual acuity (BCVA) was 20/25 Snellen. On funduscopic examination, subretinal linear changes were noted (see Fig. 1). Fundus autofluorescence (FAF) showed a remarkable pattern of hypo- and hyperfluorescent well-defined angular stripes and dotted lines around the fovea and hypofluorescent areas in the center. Mild hyperautofluorescence just superior to the vessels indicated some inferior displacement of the retina.

Fig. 1.

Images patient 1. A: Intraoperative fundus image. B and C: Fundus image, fundus autofluorescence (FAF), and optical coherence tomography (OCT) 5 months after surgery. A. Peroperatively no macular changes where seen, postoperatively (B) linear and serrated subretinal changes were noticed. In the FAF (C) these lines appeared hypoautofluorescent, additional hyperautofluorescent dotted lines where seen. Arrows 1 and 2 indicate the location of the OCT-scans below. Note slight elevation and thickening of the retinal pigment epithelium (RPE) on OCT, corresponding to hyperautofluorescent dots on FAF (white arrow head), and thinning of the RPE with an underlying hypertransmission signal on OCT corresponding to a hypoautofluorescent zone on FAF (black arrow head). Mild hyperautofluorescence just superior of the vessels indicates some inferior displacement of the retina.

Optical coherence tomography (OCT) showed focal areas of elevation and thickening of the RPE with reduced choroidal signal transmission, corresponding with hyperfluorescent areas on FAF. Focal attenuation of the RPE line with increased signal transmission on OCT corresponded with areas of hypoautofluorescence of FAF.

No treatment was given. During 1.5 years of follow-up, complaints persisted, and vision remained 20/25 Snellen. The abnormalities on OCT remained stable.

At the last follow-up, the patient developed an epiretinal membrane and thinning of the foveal neuroretina.

1.2. Case 2

A 38-year-old man presented with a shallow nasal pseudophakic retinal detachment in the left eye without macular involvement. Relevant medical history included LASIK surgery and cataract surgery one year prior. No systemic or ocular cause for the cataract was identified. Preoperative BCVA was 20/20 Snellen, and preoperative OCT images showed no abnormalities. Increased intraocular inflammation was reported, manifesting as cells in the anterior chamber and vitreous. The patient was operated on the same day, and intraoperative examination showed a giant retinal tear.

An uneventful chandelier-assisted pars plana vitrectomy was performed with triamcinolone acetonide for vitreous staining, vitreous base shaving with scleral depression and 360° peripheral retinal photocoagulation, using PFCL (DK-line®, Bausch + Lomb) for retinal reattachment. The above-mentioned intraocular infusion fluid was used. After fluid-air exchange, a gas tamponade was used (C3F8, 15 % in air), followed by a peribulbar steroid injection. Postoperatively, an upright position for one week was advised.

Significant metamorphopsia was noted upon central dissolution of the gas tamponade, one month after surgery. BCVA was 20/20 Snellen. OCT and FAF showed RPE alterations similar to the previous case, although the pattern appeared more dissipated and inferiorly located, and thereby the fovea was less affected (see Fig. 2). An inferior retinal displacement was observed.

Fig. 2.

Images patient 2. A: Fundus image 5 months after vitrectomy. B: Postoperative fluorescence angiography (FA). C: Fundus autofluorescence (FAF) and optical coherence tomography (OCT), 5 months after vitrectomy. Postoperatively linear and serrated subretinal changes were noticed corresponding to hypoautofluorescent lines and window defects on angiography. Additional hyperautofluorescent lines correspond to blocking of fluorescent signal on angiography. Slight elevation and thickening of the retinal pigment epithelium (RPE) on OCT corresponds to hyperautofluorescent dots on FAF (white arrow heads), and thinning of the RPE with an underlying hypertransmission signal on OCT corresponds to a hypoautofluorescent zone on FAF (black arrow heads). Mild hyperautofluorescence just superior and nasal of the vessels indicates some inferotemporal displacement of the retina.

Fluorescence angiography (FA) showed window defects and signal blocking, corresponding with the hypo- and hyperfluorescence seen on FAF.

During the 1.5-year follow-up, vision and symptoms remained stable. On OCT abnormalities in the parafoveal area (RPE thinning and elevation) became slightly less prominent over time.

2. Discussion

We report two cases in which RPE changes after surgery pose a burden on the visual recovery after macula-sparing retinal detachment repair. Our findings occurred after uneventful pars plana vitrectomy by two experienced surgeons, and the surgeries were separated in time by 11 months. Retrospective viewing of the surgical recordings confirmed that both surgeries were uneventful. While the gas tamponade dissolved, both patients reported symptoms of metamorphopsia. Linear, serrated, angular, and dotted patterns of RPE changes in the macula were identified by multimodal imaging, which remained stable over time.

As the symptoms and abnormalities were present at the first postoperative assessment of the macula, it was caused most likely during or immediately after the surgery.

The changes were best appreciated on FAF and FA, while corresponding OCT changes of the RPE and overlying retina were notably more subtle. The changes appear to be partial tears and accumulations of the macular RPE.

Several explanations for our unique findings were hypothesized.

We suspect an iatrogenic, mechanical mechanism rather than toxicity or inflammation due to the specific pattern and stable aspect of the RPE changes in the 1.5-year follow-up.

In our opinion, the recognizable pattern resembles a mechanical movement of a ripped part of the RPE layer, like a displaced piece of a puzzle with an absence of RPE at the proposedly ripped edge and accumulating or overlapping cells at the opposite edge, corresponding with alterations and increased or decreased transmission on OCT (see Fig. 3). These changes mimic the hyperautofluorescence seen in the folded edge of regular RPE tears and corresponding hypoautofluorescent disruption.⁴

Fig. 3.

A: Case 1, fundus autofluorescence (FAF) 5 months after surgery, B: Schematic representation of the presumed retinal pigment epithelium (RPE) movement. The vector of the retinal inferior displacement (arrows, A) corresponds to the vector of presumed RPE movement.

Interestingly, the vector of retinal displacement and presumed RPE movement is comparable. However, this finding may be unrelated because retinal displacement is a common finding after detachment surgery, presumably related to postoperative posture.⁵

According to our working hypothesis, a mechanical force leading to RPE disruption could have been exerted by liquid or gas used during surgery. Notably, PFCL was used in both cases. Although it was gently injected, it might have exerted a significant force on the underlying tissue due to its high specific gravity. Mechanical damage due to other used substances or jet stream seems implausible due to lower relative densities and the refrainment of forceful injection or infusion of any compound.

Another mechanism might be abrupt intraoperative ocular wall expansion upon recovery after hypotony. Possible critical, expansile moments during vitrectomy procedures are recovery from hypotony due to infusion-related issues and additional injection of gas tamponade after closure of the sclerotomies. RPE tears reported after glaucoma surgery have been attributed to postoperative hypotony, sometimes linked to coughing 6, 7, 8. The stretching force exercised on the globe upon increasing intraocular pressure could lead to tearing of the ocular layers, such as the RPE and Bruch's membrane, similar to severe blunt closed globe injury.⁹ The more elastic inner retinal layers and more rigid, firm sclera are typically spared in indirect traumatic choroidal ruptures.⁹ Macular choroidal ruptures and rare cases of isolated traumatic RPE tears sometimes show spontaneous closure, which was not seen in our cases.^10,11

Retinal toxicity can be caused by several intraoperatively used compounds. Although purified fluorinated carbon chains are considered biologically inert, some toxicity is seen in human RPE in vitro after 7 days of exposure on the basolateral side.¹² Several cases of acute retinal toxicity have been reported with severe visual consequences, predominantly showing progressive retinal necrosis, narrowing vessels, and additional hypo- and hyperautofluorescent subretinal pigmentary changes at the edge of the used PFCL bubble which do not resemble the macular changes in our cases.^2,13,14 Toxicity of other intraoperatively used compounds (adrenaline, gentamicin) is either inconclusive or shows a different, retinal presentation in higher dosing.^15,16 Moreover, all compounds used during the two surgeries belonged to different batches, significantly separated in time. Specific toxicities of systemic drugs have different patterns of pigment alterations not matching our findings, often with a more diffusely stippled, mottled, or concentric appearance.¹⁷ Lastly, endoilluminator-induced phototoxicity bears no resemblance to the specific pattern in our cases.¹⁸

Other macular changes, including epiretinal membranes, postoperative macular edema and retained subretinal fluid, are not uncommon after retinal detachment repair. After scleral buckling, FAF often reveals macular RPE alterations such as a granular salt-and-pepper-like pattern and alternating hyper- and hypoautofluorescent streaks, mostly in macula-off detachments.^18,19 The RPE alterations have been linked to an altered RPE metabolism related to subretinal fluid, such as an increased metabolic rate around demarcation lines and retinal microfolds leading to hyperautofluorescent streaks.^18,19 The morphology of these findings does not resemble our cases. Moreover, in the presented cases there was no subretinal fluid present in the affected areas.

Since both patients had an ocular history prior to the retinal detachment surgery, related causes of the RPE changes were also considered. In the first patient, blunt trauma in the year prior to surgery was considered an unlikely cause since the visual impairment commenced after the vitrectomy procedure. In the second case, an inflammatory component is deemed unlikely due to the specific pattern of retinal changes in our cases that does not resemble RPE and retinal changes caused by inflammatory entities.¹⁶

As the cause remains speculative and there is a low number of patients, we do not have evidence for recommendations on how to prevent this complication. Given the presumed mechanical cause, it may be advised to inject any substance into the eye slowly and away from the macula. We opted not to give any treatment (e.g., steroids) and instead monitored the patients. Although no choroidal neovascularization occurred in our patients, we suspect an increased risk at the site of disrupted RPE, similar to traumatic choroidal breaks, lacquer cracks or angioid streaks.⁹

CRediT authorship contribution statement

Viktor Verplaetse: Writing – review & editing, Writing – original draft, Visualization, Conceptualization. Saskia Helena Margaretha van Romunde: Writing – review & editing, Visualization, Conceptualization. Michele Manzulli: Writing – review & editing. Ike Schouten: Writing – review & editing. Pieter Geeraert: Writing – review & editing. Sonia Manning: Writing – review & editing. Koorosh Faridpooya: Writing – review & editing.

Patient consent

Consent to publish this case report has been obtained from the patient(s) in writing.

This report does not contain any personal identifying information.

Authorship

All authors attest that they meet the current ICMJE criteria for Authorship.

Funding

No funding or grant support.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.