Trabeculectomy in eyes with implantable collamer lens in situ: Decision-making and outcomes

Implantable collamer lens (ICL) explanation with/without clear lens extraction/glaucoma filtering surgery (GFS) is not the solution for all post-ICL glaucomas. Removal of ICL would require these patients to wear contact lenses, which becomes diifficult post-trabeculectomy in the presence of a bleb. This would compel the surgeon to resort to clear lens extraction, which is not very practical or required. One can perform GFS with ICL in situ to control the intraocular pressure (IOP) and maintain good uncorrected visual acuity in these high-myopic young eyes. Prevalence of rise in IOP post-ICL has been reported to be between 0.8% and 26.2%.[1] Various open- or closed-angle mechanisms have been described, both of which may be in the early or late postoperative period. Only isolated case reports of GFSs after ICL implantation with short-term outcomes have been reported to date.[2-4] We encountered five eyes of three patients who had intractable rise in IOP after ICL implantation and had to undergo trabeculectomy without removal of ICL. After careful evaluation and excluding all causes, with all eyes having open angles on gonioscopy, the final cause for glaucoma was preexisting juvenile open-angle glaucoma (JOAG) in four eyes and one eye had secondary glaucoma after pigment dispersion. The mean age at the time of trabeculectomy was 25.8 ± 4.49 years (22–33 years). All the patients were male, had undergone ICL insertion elsewhere, and had been referred for uncontrolled IOP. The pre-ICL mean degree of myopia was -19 ± 5.7 D (-8.00 to -24.00 D). Post-trabeculectomy, the IOP decreased from 35 ± 2.4 to 12.40 ± 2.6 mmHg at a mean postoperative follow-up of 35.8 ± 20 months. The average time from diagnosis to surgery was 29.40 ± 29.37 months (2–60 months). The visual acuity at presentation was 0.24 ± 0.21 log of minimum angle of resolution with a spherical equivalent of -1.23 ± 0.72 [Table 1]. Post-trabeculectomy, there was no difference in visual acuity or spherical equivalent; however, there was a decrease in the ICL vault from a mean of 352.40 ± 90 to 194.80 ± 71.93 µm. Three eyes had minor early postoperative complications like transient hyphema, dellen formation, and peripheral choroidal detachment (all subsided with conservative management within 1–3 weeks). Three eyes had glaucomatous changes in the optic nerve preoperatively, while 2/5 eyes still had healthy neuroretinal rims. These two eyes had no glaucomatous visual field changes. However, two eyes had biarcuate scotomas not involving fixation and the remaining eye had biarcuate scotoma with fixation involvement. All visual fields remained stable on subsequent visits. Fig. 1a shows the right eye of the patient which had undergone trabeculectomy, and Fig. 1b shows the vault on anterior segment optical coherence tomography.Figure 1: Clinical photograph showing (a) Right eye of the secondary pigmentary glaucoma patient post-trabeculectomy. (b) ASOCT showing the vault of ICL. ASOCT = anterior segment optical coherence tomography, ICL = implantable collamer lensTable 1: Data of all eyes pre- and post-trabeculectomy following post-ICL glaucomaEvaluation of the optic nerve head in myopia can be an exasperating task with a multitude of confounding factors (larger disc size with larger cup: disc ratio, difficulty in detecting retinal nerve fiber layer defects, tilted discs, peripapillary atrophy with chorioretinal degeneration, falsely low IOP readings).[5] A meticulous stereoscopic examination of the optic disc along with supplementary baseline visual fields in the event of any doubt will minimize diagnostic errors. As seen in our cases, a careful preimplantation diagnosis of JOAG would have avoided post-ICL implantation intractable glaucoma. Trabeculectomy in these eyes can be very challenging owing to the eyes being highly myopic with inherent complications of hypotony and posterior segment complications and the added risk of the ICL. The retained ICL in the eye may pose additional challenges with cataract and corneal complications in view of shallow anterior chamber. Avoiding intraoperative and postoperative hypotony is of prime importance to prevent all these complications. A very careful, cautious, and meticulous approach during surgery is recommended to prevent pigment dispersion due to coarse or hurried intraoperative manipulation, and shallow anterior chamber should be strictly avoided. Some recommended measures that would be helpful are slow decompression, anterior chamber reformation, use of releasable sutures with judicious use of antimetabolites (low dose or concentration), and intra- and/or postoperative cycloplegia. The few reports of post-ICL trabeculectomy include two cases having secondary pigment dispersion,[3,4] with one of the cases requiring explantation of ICL.[4] Management with Ex-Press shunt has been described in a case with combined preexisting JOAG and pigment dispersion.[2] Extra caution is required for shunts to prevent postoperative shallow anterior chamber, which comes with the inherent complications of possible contact of ICL with the iris or crystalline lens. These would inevitably lead to iridocyclitis, pigment dispersion, and/or cataract, not forgetting corneal decompensation if the tube touches the endothelium. Therefore, trabeculectomy seems to be a better option, with minimal complications as seen in our series. All the eyes had a stable ICL, stable visual fields, and no cataract or any serious vision-threatening complications post-trabeculectomy. Decrease in ICL vault post-trabeculectomy was noted, and this is most likely due to the decrease in IOP with forward shifting of the lens iris diaphragm. Therefore, follow-up of these patients is crucial to note any cataractogenesis. Correct diagnosis of the mechanism of glaucoma post-ICL along with prompt management is indispensable as treatments differ markedly and vision can be salvaged. Prevention is of more paramount importance. Glaucoma post-ICL is a completely avoidable complication occurring in young patients with a long life expectancy, where proper preoperative screening and planning plays a big role. Trabeculectomy without the need for removal of ICL is a viable option to stabilize IOP and maintain visual acuity.