Factors to consider in IOP elevations associated with vitreoretinal treatments

Basil Williams, Jr., MD, reported on the association between development of elevated intraocular pressure (IOP) and numerous commonly performed vitreoretinal treatments.

In addition to the use of steroids, those treatments include administration of intravitreal anti-vascular endothelial growth factor (VEGF) therapy, application of panretinal photocoagulation (PRP), use of scleral buckles, and pars plana vitrectomy (PPV), the last of which uses intravitreal gas or silicone oil.

Williams is the Mary Knight Asbury Chair of Ocular Oncology and assistant professor, Department of Ophthalmology, University of Cincinnati College of Medicine.

Intravitreal anti-VEGF injections
Tens of millions of anti-VEGF injections that have been administered since their introduction for various vitreoretinal diseases, especially for age-related macular degeneration (AMD), generally seem to cause immediate IOP elevations that remain elevated in a subset of patients.

Investigators have been faced with numerous questions concerning the injection duration/frequency, specific medications, injection technique, underlying diagnosis, and importantly the effect on patients with preexisting glaucoma.

The potential to prevent IOP elevations is another question.

A history of glaucoma seems to be the most important factor in the potential for sustained IOP elevations following intravitreal injections.

However meta-analyses do not agree on that risk with a significant number of injections, but 1 study did indicate an increased risk of sustained IOP elevations. Randomized clinical trials are too heterogenous to allow valid comparisons.

The IRIS Registry study² results indicated that the specific drugs used may be instrumental in elevated IOPs, in that ranibizumab (Lucentis, Genentech) and bevacizumab (Avastin, Genentech) were associated with significantly higher rates of IOP increases compared with aflibercept (Eylea, Regeneron Pharmaceuticals).

Subconjunctival drug reflux may cause ocular hypertension immediately after intravitreal injections.³

The authors found a 19.9-mmHg difference between eyes with and those without reflux following injections.

The same authors recommended performing ocular depression using a cotton tip soaked in lidocaine to reduce IOP immediately after injections.

The important considerations after anti-VEGF injections are the presence of existing glaucoma, injection duration/frequency, technique, and preventative measures.

PPV
Williams pointed out that sustained IOP elevations and glaucomatous damage following PPV mostly are associated with open-angle glaucoma.

In cases in which intravitreal gas is injected, topical medications can address mild increases in IOP.

However, removal of some gas may be need with significant IOP elevations if the eye is overfilled; when an improper gas concentration was used, a second surgery may be needed.

When silicone oil is used, attention should be paid to the appropriate volume and a face-down position postoperatively is important. In these cases, the peripheral iridotomy can close with pupillary block.

Oil removal is helpful, but bubbles can remain in the trabecular meshwork. If insufficient oil is removed, a drainage device may be needed.

In the presence of synechial angle closure, cyclophotocoagulation may be possible. Finally, silicone oil exchange is another option.

Scleral buckle
When a scleral buckle is placed, angle closure rarely occurs; anterior chamber shallowing without closure occurs more often; the scenario often resolves spontaneously.

Treatment options include topical cycloplegics, steroids, and aqueous suppressants. The mechanisms of interference by the scleral buckle include placement of a high buckle, blocked vortex veins, anterior segment ischemia, and choroidals.

PRP
When treating a closed angle, anterior displacement of the lens-iris diaphragm and damage to the short ciliary nerves can cause decreased ciliary muscle tone and release of prostaglandins.

Such damage can be managed with topical medications such as cycloplegics and aqueous suppressants, Williams advised.

The take-home messages regarding IOP elevations after vitreoretinal procedures are as follows:

• Sustained elevations of IOP are a risk following anti-VEGF injects as a result of the injection and duration and the presence of baseline glaucoma

• Almost all vitreoretinal surgeries carry the increased risk of development of glaucoma via different mechanisms

• Surgeons should take appropriate steps to minimize this risk.



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Basil K. Williams, Jr., MD
E:basilkwilliams@gmail.com
This article is adapted from Williams’s presentation at the Association for Research in Vision and Ophthalmology annual meeting, July 23, 2021. He is a consultant to Castle Biosciences and Genentech.

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Reference

1. Zhou Y, Zhou M, Xia S, et al. Sustained elevation of intraocular pressure associated with intravitreal administration of anti-vascular endothelial growth factor: a systemic review and meta-analysis. Sci Rep. 2016 Dec 21;6:39301.

2. Atchison EA, Wood KM, Mattox CM, et al. The real-world effect of intravitreous anti-vascular endothelial growth factor drugs on intraocular pressure. An analysis using the IRIS Registry. Ophthalmology 2 Vol. 125:676–82; Published online: January 11, 2018.

3. Bracha P, Moore NA, Ciulla TA, et al. The acute and chronic effects of intravitreal anti-vascular endothelial growth factor injections on intraocular pressure: A review. Surv Ophthalmol. 2018;63:281-95.