Phaco for angle-closure glaucoma?
Early cataract removal may be indicated for uncontrolled angle closure
Is cataract surgery an appropriate treatment for patients with primary angle closure (PAC) or primary angle-closure glaucoma (PACG)? The answer largely depends on whether the patient has a visually significant cataract, and whether intraocular pressure (IOP) can be medically controlled, according to Anjali Bhorade MD.
PAC is currently defined as 180° or more of iris-trabecular contact with elevated IOP or peripheral anterior synechiae, or both. PACG is the same plus glaucomatous optic neuropathy.
(Emanuel et al. Current Ophthalmol, 2014).
The current first line treatment is laser peripheral iridotomy (LPI), but this is not always successful. Since angle closure often involves a thick or anteriorly positioned lens that pushes the iris forward, crowding the angle (Shams PN and Foster PJ, J Glaucoma, 2012), removing the lens may at least partially address the underlying anatomical defect. But cataract surgery carries its own risks so it’s important to know when those risks are justified.
A visually significant cataract shifts the odds toward phaco. Phaco alone may lower IOP nearly as much as phaco combined with trabeculectomy in patients with medically controlled chronic angle closure glaucoma (CACG), though more medications may be needed without filtration surgery, Dr Bhorade said (Tham CC et al, Ophthalmology, 2008). However, combined phaco-trab may be more effective for patients with medically uncontrolled CACG (Tham CC et al, Ophthalmology 2009).
Studies also show that phaco lowers IOP more than LPI in angle closure patients with visually significant cataracts (Lam DS et al, Ophthalmology 2008. Hussain R, Ophthalmology 2012). So phaco often makes sense for treating angle closure in these patients, Dr Bhorade said.
The question is less clear for patients without visually significant cataracts. If IOP can be medically controlled after LPI, the risks of phaco may not be justified, and monitoring may be the better option, Dr Bhorade said. But if LPI fails, phaco can be effective without a visually significant cataract (Dada T et al, J Cataract Refract Surg 2015), and may work as well as trabeculectomy (Tham CC et al, Ophthalmology 2013).
Whether phaco works better than LPI as a first line treatment is the subject of the Effectiveness in Angle-Closure Glaucoma of Lens Extraction (EAGLE) study currently underway in the UK, Asia and Australia, Dr Bhorade said.
Anjali Bhorade: firstname.lastname@example.org