Here is an article I wrote that describes my initial approach to most adult glaucoma with early uncomplicated cataract surgery and Hydrus stent.
Currently, IOP reduction is the only way we can help reduce or even stop glaucoma progression. Due to higher rates of blindness in vulnerable poorer groups with decreased access to expensive medications, safer, uncomplicated cataract extraction/refractive lensectomy and microinvasive trabecular bypass surgery should be considered earlier.
We need more studies with randomized controlled clinical trials comparing earlier cataract surgery and trabecular bypass to medical, and laser therapies in order to reassess our algorithm for treating enlarged lens-related glaucoma in adults over the age of 50.
Discussion (excerpts only)
Cataract and age-related changes in the lens play a significant role in glaucoma.3 Cataract surgery alone can reduce intraocular pressure in glaucoma from 13 to 73%4 and in angle closure has been shown to be more effective than laser iridotomy.5 With age, the lens's volume and width increases.6 The increase in width allows for greater iridolenticular contact to occur. This leads to increased contact between the lens zonules and posterior iris pigment epithelium. During accommodation, there is posterior bowing of the iris and increased width of the lens. The increased iridolenticular contact leads to pigment liberation that obstructs the inferior trabecular meshwork often seen more inferiorly than superiorly on gonioscopy. The growth in volume lens also compresses the trabecular meshwork and Schlemm's canal.6 The increase in lens volume also leads to narrowing of the anterior angle structures.5
Investigators have also noted that following cataract extraction, Schlemm's canal, a conventional outflow pathway, expands and IOP decreases with the degree of expansion.9 Various studies have demonstrated that cataract extraction significantly lowers IOP in glaucoma patients.2
Therefore, we propose for patients over the age of 50 with glaucoma to consider undergoing early uncomplicated cataract extraction/refractive lensectomy and microinvasive trabecular bypass as the first step of treatment. This will often remove the enlarged lens as the primary cause of glaucoma. The microinvasive trabecular bypass will also restore physiologic outflow via Schlemm's canal, collector channels, and the aqueous veins.11 This procedure is not only efficacious; it is also safe with few or no patients suffering vision-threatening microstent-related adverse events.11,12 Song et al. most recently published a longitudinal study suggesting that lens extraction is best performed early to prevent primary angle closure glaucoma.13
Declaration of Competing Interests
Daniel Laroche is a consultant with Ivantis and on the Speaker Bureau with Aerie and Baucsh Health