Clinical Presentation and Treatment Outcomes of Pupillary Block Glaucoma Following Vitreoretinal Surgery

PURPOSE

To describe the clinical presentation and treatment outcomes of pupillary block glaucoma (PBG) following vitreoretinal surgery (VR surgery).

MATERIAL AND METHODS

Retrospective observational study of 6941 patients, who underwent VR surgery at a tertiary eye care centre in South India between January 2015 and December 2019. Amongst them, clinical data of 61 patients who developed PBG were taken for statistical analysis.

RESULTS

Mean (SD) age was 53.90 (13.4) years and the incidence of PBG was .87%. Median (IQR) time of onset of PBG following VR surgery was 3.33 (1.1-6.6) months and majority were pseudophakic (75%). PBG resolved with Nd:YAG laser peripheral iridotomy (LPI) alone in 50 (82%) patients, whereas 11(18%) patients required additional interventions like surgical iridectomy, trabeculectomy or diode laser cyclophotocoagulation (CPC) either as a stand-alone procedure or in combination with silicone oil removal (SOR). Mean (SD) intraocular pressure at the onset of PBG was 41.61 (14.5) mmHg, which reduced drastically following LPI to 24.28 (14.9) mmHg which further dropped significantly at 6 months follow up to 20.34 (13.9) mmHg.

CONCLUSIONS

Incidence of secondary PBG after VR surgery was .87%, and we observed diabetes mellitus, combined cataract and VR surgery, use of 1000cs SO endotamponade, intraoperative endolaser and multiple VR surgical interventions as common associations. Majority of the patients with PBG after VR procedures resolved with LPI and medical management. Few individuals (18%) required additional laser or surgical intervention for IOP control.

A New Mechanism of Silicone Oil-Induced Glaucoma and Its Management

Purpose. To describe a case of secondary acute angle closure glaucoma due to silicone oil migration into the posterior chamber causing entrapment of aqueous and its successful management. Case Presentation. A 69-year-old female presented with decreased vision and pain in the left eye (LE) for one month. She had a history of complicated phacoemulsification with nucleus drop and retinal detachment in LE, for which vitreoretinal surgery with silicone oil endotamponade was done. She was also a known case of primary open angle glaucoma on medications. The corrected distance visual acuity was 20/20 and 20/125 in the right eye (RE) and LE, respectively. The intraocular pressure (IOP) was 18 mmHg in RE and 45 mmHg in LE. Anterior segment examination of LE revealed 270° of iridocorneal apposition in the periphery of the anterior chamber. Fundus examination of LE showed silicone oil filled vitreous cavity with attached retina. Given the recent history of silicone oil injection and elevated IOP despite maximum antiglaucoma medications, we decided to perform laser peripheral iridotomy (LPI) in the area of iridocorneal apposition. Following LPI, the IOP in LE came down to 17 mmHg and remained stable within the normal range for one month, after which the patient was taken up for silicone oil removal. Conclusion. This case report highlights a new mechanism of silicone oil-induced glaucoma and the technique of performing LPI in the area of iridocorneal apposition, for the first time in the literature. Silicone oil migration into the posterior chamber from the vitreous cavity in the presence of zonular dehiscence can push the iris forward and lead to iridocorneal apposition, resulting in an acute rise in IOP. Performing LPI within the area of iridocorneal apposition can help the aqueous seep into the anterior chamber and release the silicone oil globule trapped behind the iris to enter the anterior chamber, thus relieving the iridocorneal adhesions and lowering the IOP.

Intraocular Pressure Rise Linked to Silicone Oil in Retinal Surgery: A Review

Silicone oil represents the main choice for intraocular tamponade in cases of complicated retinal detachment surgery. The intraocular pressure of an eye filled with silicone oil could increase, driven by a variety of different forces, according to several mechanisms. Two main conditions have been highlighted, depending on the onset: early hypertension or late glaucoma. The different types of silicone oils and their physico-chemical properties are varied and may play a role in the determination of intraocular pressure rise. The current body of literature allows for the illustration and categorization of the incidence and risk factors, as well as the pathogenesis and the management of the early postoperative hypertension subtended by an open- and closed-angle, along with the late onset silicone oil-induced glaucoma. Understanding the leading actors on the stage of ocular pressure elevation concurrently with silicone oil application for retinal surgery could help in guiding the timely and appropriate course of treatment.

Estimating three-dimensional outflow and pressure gradients within the human eye

In this paper we set the previously reported pressure-dependent, ordinary differential equation outflow model by Smith and Gardiner for the human eye, into a new three-dimensional (3D) porous media outflow model of the eye, and calibrate model parameters using data reported in the literature. Assuming normal outflow through anterior pathways, we test the ability of 3D flow model to predict the pressure elevation with a silicone oil tamponade. Then assuming outflow across the retinal pigment epithelium is normal, we test the ability of the 3D model to predict the pressure elevation in Schwartz-Matsuo syndrome. For the first time we find the flow model can successfully model both conditions, which helps to build confidence in the validity and accuracy of the 3D pressure-dependent outflow model proposed here. We employ this flow model to estimate the translaminar pressure gradient within the optic nerve head of a normal eye in both the upright and supine postures, and during the day and at night. Based on a ratio of estimated and measured pressure gradients, we define a factor of safety against acute interruption of axonal transport at the laminar cribrosa. Using a completely independent method, based on the behaviour of dynein molecular motors, we compute the factor of safety against stalling the dynein molecule motors, and so compromising retrograde axonal transport. We show these two independent methods for estimating factors of safety agree reasonably well and appear to be consistent. Taken together, the new 3D pressure-dependent outflow model proves itself to capable of providing a useful modeling platform for analyzing eye behaviour in a variety of physiological and clinically useful contexts, including IOP elevation in Schwartz-Matsuo syndrome and with silicone oil tamponade, and potentially for risk assessment for optic glaucomatous neuropathy.

Retina and glaucoma: surgical complications

Background

The close structural and microcirculatory co-relation between anterior and posterior segments of eye make them very vulnerable to complications when one of them is affected surgically. With the advent of anti-fibrotic agents in the management of glaucoma, the rates of vitreoretinal complications have become more frequent.

Main body

Common retinal complications after glaucoma surgeries include choroidal detachment; ocular decompression retinopathy; haemorrhagic choroidal detachment; hypotony maculopathy; malignant glaucoma; vitreous haemorrhage; bleb endophthalmitis; retinal detachment. Similarly, intraocular pressure rise is often noted after scleral buckle; pars plana vitrectomy; intravitreal gas injection; silicone oil injection; intravitreal steroid injection.

Conclusion

The article provides some insight into some of the complications after glaucoma and retina surgeries, including the pathogenetic mechanisms behind each complication and available management options.