Secondary pigmentary glaucoma in patients with underlying primary pigment dispersion syndrome

Prevalence of zonulopathy in primary angle closure disease

Background

To determine the prevalence of zonulopathy in a large cohort of eyes with primary angle closure disease (PACD) that underwent cataract surgery.

Methods

Retrospective consecutive case series of PACD eyes (including primary angle closure suspect, primary angle closure, and primary angle closure glaucoma) that underwent phacoemulsification cataract surgery or clear lens extraction between 2009 and 2020 at a single ophthalmology centre. Those with risk factors for zonulopathy such as history of trauma, pseudoexfoliation syndrome, intraocular surgery, retinitis pigmentosa or connective tissue disorders were excluded. The primary outcomes included the prevalence of zonulopathy assessed intraoperatively and secondary pigment dispersion syndrome.

Results

In our cohort of 806 consecutive PACD eyes, the prevalence of zonulopathy was 7.3% (59 of 806 eyes) – significantly greater than the 0.46%–2.6% range reported for the general population (p < 0.001). Intraoperative signs of zonular weakness included floppy capsular bag (29 eyes, 3.6%), zonular laxity (25 eyes, 3.1%) and zonular dehiscence (11 eyes, 1.4%). Among these eyes, capsular tension ring was used in 23 eyes (39.0%), six eyes (10.2%) experienced vitreous prolapse intraoperatively and underwent anterior vitrectomy, and two eyes (3.4%) experienced posterior capsular rupture, one of which required a scleral‐fixated intraocular lens. Secondary pigment dispersion syndrome was observed in 141 eyes (17.5%).

Conclusions

This study evidenced a high prevalence of zonulopathy among a large cohort of PACD eyes and suggests zonulopathy as a possible under‐recognised cause of angle closure. Until more sophisticated imaging modalities become available, awareness about the prevalence of zonulopathy in angle closure disease coupled with careful preoperative examinations can help minimise or prevent the complications of zonulopathy.

A case of dense pigment deposition of the posterior lens capsule

BACKGROUND

Pigment dispersion syndrome (PDS) is a well-known entity which can lead to pigmentary glaucoma (PG). This case report presents a rare presentation of PG with bilateral dense pigment deposits of the posterior lens capsule.

CASE PRESENTATION

A 72-year-old male came for his first appointment due to an asymmetric worsening of visual acuity. The examination showed unilaterally severely increased intraocular pressure, bilateral dense pigment deposition of the posterior lens capsule, and a shallow unilateral optic disk excavation. Gonioscopy revealed moderate pigmentation of the angle and a concave configuration of the peripheral iris in both eyes. The standard slit lamp examination showed no transillumination defects of either iris. Optical coherence tomography showed retinal nerve fiber layer (RNFL) thinning in the peripapillary and macular regions. An antiglaucoma medication was prescribed with a good lowering effect.

CONCLUSION

Pigment deposition of the posterior lens capsule, which has been rarely reported, is a possible important sign of PDS or PG.

Efficacy and Safety of Trabeculectomy Versus Nonpenetrating Surgeries in Open-angle Glaucoma: A Meta-analysis

PURPOSE

The purpose of this study was to conduct a meta-analysis on the efficacy and safety of trabeculectomy (TE) and nonpenetrating glaucoma surgery (NPGS) techniques in patients with primary open-angle glaucoma, pseudoexfoliation glaucoma, pigmentary glaucoma, and normal-tension glaucoma.

METHODS

All studies were identified by searching electronic sources (PubMed, Medline, Scopus, and Embase) until February 5, 2018. Primary outcome was mean intraocular pressure (IOP) reduction at 6, 12, and 24 months. Complications, number of antiglaucomatous medications, and visual outcomes were also evaluated.

RESULTS

Twenty-one studies were included. Ten studies compared TE with deep sclerectomy (DS), 5 with viscocanalostomy (VC), 1 study with both DS and VC, and 5 with canaloplasty (CP). TE was superior to DS, VC, and CP in reducing IOP at 6 and 12 months, and to DS at 24 months. When comparing TE to VC and to CP at 24 months, there was no significant difference in IOP reduction. Hypotony, choroidals, anterior chamber shallowing or flattening, and cataract formation or progression were more associated with TE than with NPGSs. TE was more effective in reducing antiglaucomatous medications than VC and CP.

CONCLUSIONS

TE is more effective in reducing IOP. TE presents a higher risk of complications as compared with NPGS, except for hyphema.

Intraocular pressure elevation precedes a phagocytosis decline in a model of pigmentary glaucoma

Background: Outflow regulation and phagocytosis are key functions of the trabecular meshwork (TM), but it is not clear how the two are related in secondary open angle glaucomas characterized by an increased particle load. We hypothesized that diminished TM phagocytosis is not the primary cause of early ocular hypertension and recreated pigment dispersion in a porcine ex vivo model.

Methods: Sixteen porcine anterior chamber cultures received a continuous infusion of pigment granules (Pg), while 16 additional anterior chambers served as controls (C). Pressure transducers recorded the intraocular pressure (IOP). The phagocytic capacity of the trabecular meshwork was determined by fluorescent microspheres.

Results: The baseline IOPs in Pg and C were similar ( P=0.82). A significant IOP elevation occurred in Pg at 48, 120, and 180 hours (all P<0.01, compared to baseline). The pigment did not cause a reduction in TM phagocytosis at 48 hours when the earliest IOP elevation occurred, but at 120 hours onward ( P=0.001 compared to C). This reduction did not result in an additional IOP increase at 120 or 180 hours compared to the first IOP elevation at 48 hours ( P>0.05).

Conclusions: In this porcine model of pigmentary glaucoma, an IOP elevation occurs much earlier than when phagocytosis fails, suggesting that two separate mechanisms might be at work.