Morphological and functional retinal changes in postoperative hypotony

Aim: to analyze the retinal microvascular network changes in hypotony maculopathy after non-penetrating deep sclerectomy (NPDS). Patients and Methods: the study enrolled 35 patients (35 eyes) with uncontrolled glaucoma stages II and III in whom the intraocular pressure (IOP) level was less than 10 mm Hg after NPDS. In addition to a standard eye exam, all patients underwent optical coherence tomography angiography (OCTA) before and one day after surgery. In addition, the radial peripapillary capillary (RPC) network vessel density (VD) on 4×4-mm optic nerve scans, superficial vascular plexus (SVP) VD on 6×6-mm macular scans, and foveal avascular zone (FAZ) area on 3×3-mm scans were evaluated. Results: IOP-lowering effect was reported in all patients, i.e., IOP level reduced by, on average, 17.7±8.3 mm Hg. In 15 patients, baseline OCTA parameters worsened (group 1). In 17 patients, OCTA parameters improved (group 2). In 3 patients, OCTA parameters remained unchanged (group 3). In group 1, parafoveal VD reduced by 1.5% [2.45%; 0.85%] in the superior sector and 1.3% [1.75%; 0.85%] in the inferior sector. Peripapillary VD reduced by 0.6% [2.0%; 0.1%] in the superior sector and 1.1% [2.4%; 0.0%] in the inferior sector. In group 2, parafoveal VD improved by 0.85% [0.0%; 1.75%] in the superior sector and 1.2% [0.68%; 2.6%] in the inferior sector. Peripapillary VD improved by 1.2% [0.18%; 2.0%] in the superior sector and 0.95% [0.05%; 1.75%] in the inferior sector. IOP levels were similar. No correlations between OCTA parameters and IOP levels were revealed. Postoperatively, the FAZ area remained unchanged. Conclusions: postoperative hypotonia has a positive and negative impact on the retinal microvascular network. OCTA findings after NPDS demonstrate no correlations with IOP levels. Further studies are needed to identify prognostic factors of hypotony maculopathy and assess its long-term effects on retinal vessels. Keywords: glaucoma, non-penetrating deep sclerectomy, hypotony maculopathy, OCTA. For citation: Erichev V.P., Antonov A.A., Vitkov A.A. et al. Morphological and functional retinal changes in postoperative hypotony. Russian Journal of Clinical Ophthalmology. 2021;21(4):187–193 (in Russ.). DOI: 10.32364/2311-7729-2021-21-4-187-193.

One-year outcomes of stand-alone ab externo SIBS microshunt implantation in refractory glaucoma

Background/AimsDetermine the efficacy of stand-alone implantation of the ab externo SIBS or poly(styrene-block-isobutylene-block-styrene) microshunt with mitomycin C in glaucomatous eyes, refractory to previous subconjunctival filtering surgery, over 1 year of follow-up.MethodsConsecutive retrospective cohort of patients with intraocular pressure (IOP) above target and previous subconjunctival filtering surgery, who received the microshunt between July 2015 and April 2019. Primary outcome was a complete success, with failure defined as IOP <6 mm Hg with vision loss, >17 mm Hg or <20% reduction in IOP without medications. Secondary outcomes included thresholds of 6 to 14 mm Hg and 6 to 21 mm Hg for both complete (no medications) and qualified (with medications) success as well as qualified success for thresholds of 6 to 17 mm Hg. Risk factors for failure, IOP, medications and complications were also assessed.Results85 eyes of 79 patients with a preoperative median IOP of 22.0 mm Hg (IQR 18.0–29.0) on four (IQR 3–4) medications were included. Postoperative median IOP was 13.0 mm Hg (IQR 10.0–17.0) on zero (IQR 0–2) medication at 1 year. 61.0% achieved complete success and 79.7% achieved qualified success. Mild-to-moderate disease was associated with failure (adjusted HR 2.37; 95% CI 1.23 to 4.59). Needling was performed in 11.8%, and 8.2% underwent anterior chamber reformation. Complications were transient, consisting of hyphaema, choroidal detachment and hypotony maculopathy, with 7.1% of patients undergoing reoperation.ConclusionsIn a group of high-risk eyes that had already failed at least one subconjunctival filtering surgery, the SIBS microshunt demonstrates reasonable surgical success over 1-year follow-up, with relatively few complications.

Concurrent Phacoemulsification and Encircling for Hypotony Maculopathy after Blunt Trauma

A 37-year-old Japanese man had his right eye hit by a fist. His right eye developed hypotony maculopathy and secondary cataract, and his visual acuity decreased to 20/200 with an intraocular pressure of 4 mmHg. He underwent phacoemulsification and aspiration, implantation of the intraocular lens, and encircling with a silicone tire. His visual acuity improved to 20/20 and stable for more than one year postoperatively. The intraocular pressure in his right eye increased to 12 mmHg, and maculopathy was resolved entirely. It was suggested that an encircling buckle obstructed the uveoscleral outflow through the cyclodialysis and increased intraocular pressure. Concurrent cataract surgery and encircling was sufficient to improve the vision.