Phacolytic glaucoma is a form of secondary, open-angle glaucoma that is related to leakage of high molecular weight proteins through microscopic openings in the capsule of a hypermature cataract. The image of this Morgagnian cataract is from EyeRounds.org at the University of Iowa.
Speaker: Dr. Malik Y. Kahook, Professor of Ophthalmology, University of Colorado, USA
Dr. Kahook: Lens induced glaucoma can be subdivided into distinct categories that include: 1. Phacolytic Glaucoma, 2. Lens Particle Glaucoma and 3. Phacoantigenic Glaucoma. I will cover Phacolytic Glaucoma in this session of 1 Slide in 5 Minutes.
Phacolytic glaucoma is a form of secondary open angle glaucoma that is related to leakage of high molecular weight proteins through microscopic openings in the capsule of a hypermature cataract. This leads to inflammation with clogging of the trabecular meshwork by proteins as well as macrophages that engulf the proteins and other inflammatory debris. All of these factors lead to an increase in intraocular pressure (IOP) that can be acute in nature with significant pain and corneal edema. Patients often present with a painful red eye, photophobia and decreased visual acuity. Slit lamp exam may reveal a pseudohypopyon composed of layered proteinaceous deposits. Close examination of the lens capsule may reveal wrinkling due to loss of lens mass with a mature/hypermature cataract. Gonioscopy, if corneal edema allows, should be performed to rule out presence of neovascularization and fibrovascular membranes (causing neovascular glaucoma) and dilated fundus examination should be completed, if visualization is possible, to identify posterior segment pathologies that can cause inflammation/neovascularization. Ultrasound testing should be used to examine the eye if visualization is not possible on dilated fundus exam. All of these steps are taken to rule out disease processes that might mimic (or potential coexist) with phacolytic glaucoma. The inflammation associated with leakage of proteins through the lens capsule may lead to posterior synechiae which will require attention at the time of cataract surgery, through lysing of the synechiae with various techniques, and can make extraction of the lens more difficult. There are other forms of open angle glaucoma that occur due to inflammation and the lack of keratic precipitates (KP) distinguishes phacolytic glaucoma from some of these other processes. Phacoantigenic glaucoma, a different form of lens induced glaucoma, is one example that exhibits inflammation with rise in IOP but does have coexistent KP. As mentioned before, we will cover other lens induced glaucomas in subsequent lectures.
The immediate goal is to decrease IOP and inflammation. Several topical IOP lowering drops are usually required to lower pressure including prostaglandin analogues, beta blockers and carbonic anhydrase inhibitors among others. Miotics, like pilocarpine, should be avoided as they might increase inflammation and formation of synechiae. Cycloplegics, like atropine, can be used to assist in breaking posterior synechiae and/or to avoid formation of new synechiae. Steroid drops can be used several times per day with the goal of bridging the patient to the definitive treatment which is cataract extraction. Cataract extraction should take place as soon as possible while still allowing for some time to control IOP and clear the edematous cornea when possible. It is important to note that combining glaucoma surgery, like trabeculectomy, with cataract surgery is not needed in this circumstance since cataract surgery alone is often “curative” unless the disease process has been present for a long period of time (months) and the outflow system of the eye has been severely compromised. A fortunate consequence of the pain and acute decrease of vision involved with phacolytic glaucoma is that patients often present to eye care professionals within days or weeks of symptoms thus allowing for intervention with standalone cataract surgery. There are exceptions of course, particularly in resource challenged areas around the globe, and consideration for combined cataract-glaucoma surgery should be considered when appropriate. Postoperatively, patients often must remain on IOP lowering drops for days to weeks along with steroids to decrease inflammation. Weaning off glaucoma drops is often possible and depends on the level of compromise to the aqueous outflow system. Every patient should undergo dilated fundus examination with optic nerve assessment as visualization improves to the back of the eye. Visual field testing can set a baseline for presence or absence of optic neuropathy and extended follow up, when possible, should be instituted to ensure recovery and addressing any future needs of the patient.
June 14, 2021