Postoperative Complications of Cataract Surgery

Overview

The complications that present after cataract surgery, rather than during it, cluster into a few recognizable timing bands. A sterile inflammatory reaction confined to the anterior segment within the first day suggests toxic anterior segment syndrome. Pain, hypopyon, and vitritis in the first several days suggest infectious endophthalmitis. Painless blurring that develops weeks later, with a petaloid pattern on OCT, points to cystoid macular edema. A slow, low-grade inflammation appearing months after an otherwise uneventful surgery suggests a different, more indolent infection altogether. Time course is often more diagnostically useful than the exam findings themselves, since several of these entities look similar at the slit lamp.

Pseudophakic Cystoid Macular Edema (Irvine-Gass Syndrome)

Pseudophakic cystoid macular edema, also called Irvine-Gass syndrome, typically presents weeks after cataract surgery (classically 4 to 8 weeks) with gradual, painless blurring of vision. OCT shows multiple hyporeflective, fluid-filled cystic spaces within a thickened, elevated macula. These cysts form within the outer plexiform (Henle's) layer and the inner nuclear layer, reflecting a breakdown of the blood-retinal barrier at that level. The mechanism is thought to be inflammatory: prostaglandin release during and after surgery increases perifoveal capillary permeability, letting fluid accumulate in the outer retina. First-line management is combined topical NSAIDs and corticosteroids, reserving intravitreal injections and other invasive options for cases that don't respond. Most resolve with medical treatment alone.

Acute & Chronic Postoperative Endophthalmitis

Acute postoperative endophthalmitis is the complication every cataract surgeon watches for in the first week after surgery: a rare but potentially devastating intraocular infection presenting within days with significant pain, marked vision loss, and hypopyon. Prompt recognition and treatment (intravitreal antibiotics, often with vitreous tap and culture) limits the degree of permanent visual loss.

Chronic postoperative endophthalmitis is a separate, far more indolent presentation that can appear months after an otherwise unremarkable surgery. The classic organism is Cutibacterium acnes (formerly Propionibacterium acnes), a low-virulence organism that sequesters within the capsular bag rather than actively invading the eye. The resulting inflammation is correspondingly low-grade, often with a characteristic white intracapsular plaque on exam, and is easily mistaken for recurrent, steroid-responsive uveitis unless the surgical history and the plaque are specifically sought.

Toxic Anterior Segment Syndrome (TASS)

Toxic anterior segment syndrome is a sterile, noninfectious inflammatory reaction of the anterior segment caused by contaminants introduced during surgery: residual detergents, endotoxin, or improperly rinsed instruments, rather than living organisms. Because it is a chemical injury and not an infection, treatment is intensive topical corticosteroids rather than antibiotics. Outcomes are generally favorable once the source of contamination is identified and eliminated from the instrument-processing chain.

The distinction that matters most clinically is separating TASS from acute infectious endophthalmitis, since both can present early with anterior segment inflammation. Endophthalmitis brings significant ocular pain and vitreous involvement (vitritis); TASS is typically painless, presents earlier (within 12 to 24 hours rather than several days), and stays confined to the anterior segment. Getting this right the first time matters: treating true endophthalmitis as TASS delays sight-saving intravitreal antibiotics, while treating TASS as endophthalmitis exposes the patient to an injection they didn't need.

Phacomorphic Glaucoma as a Delayed-Surgery Risk

Phacomorphic glaucoma is not a complication of surgery but a complication of delaying it. As a cataract advances and becomes intumescent (swollen), the enlarging lens pushes the iris forward, closing the iridocorneal angle and blocking aqueous outflow through a pupillary-block mechanism. The result is a secondary acute angle-closure glaucoma that resolves only once the swollen lens is removed. Watchful waiting on a visually significant cataract is therefore not risk-free: an intumescent lens creates its own ophthalmic emergency, separate from and in addition to the visual decline that brought the patient in.

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