Late-Onset Capsular Distension Syndrome: A Rare Cause Of Postoperative Vision Loss

The purpose of this case is to highlight the clinical presentation, diagnosis, and management of capsular distension syndrome (CDS), a rare complication following phacoemulsification.

Tertiary referral hospital Fundación Jiménez Díaz, Madrid, Spain.

A 66-year-old male presented to the emergency department complaining of vision loss in his left eye (LE). He described the blurry vision as a “whiteness” affecting his entire visual field.

His ophthalmologic history included multiple corneal surgeries on his right eye due to corneal thinning, as well as cataract surgery in both eyes seven years prior.

A comprehensive ophthalmologic examination was performed. His visual acuity (VA) was 1.0 in both eyes, with normal intrinsic ocular motility, an intraocular pressure (IOP) of 14 mmHg on the LE, and an unremarkable fundoscopy. Biomicroscopy of the LE revealed a white-brown, viscous substance located behind the intraocular lens (IOL). Anterior segment optical coherence tomography (AS-OCT) showed a hyperreflective material behind the IOL, in the virtual space between the posterior IOL surface and the posterior capsule.

Based on these findings, a diagnosis of capsular distension syndrome was established. Treatment consisted of Nd:YAG capsulotomy in the LE, followed by topical timolol combined with brimonidine and a tapered regimen of dexamethasone.

At the 24-hour follow-up, the patient reported improved VA, IOP remained within normal limits and a new AS-OCT was performed that showed no signs of capsular distension syndrome.

Capsular distension syndrome (also known as capsular block syndrome) is a rare condition occurring in approximately 0.73% of patients undergoing phacoemulsification. It is classified as either early-onset or late-onset capsular distension syndrome. Different theories exist regarding the pathogenesis of late-onset capsular distension syndrome, with the most widely accepted one attributing it to residual lenticular epithelial cells that undergo metaplasia and proliferate, producing various types of collagen and extracellular matrix, which accumulate in the capsular bag. Patients typically present with decreased visual acuity, and an opaque fluid can be observed between the intraocular lens (IOL) and the posterior capsule.