Case series: Late capsular block syndrome associated with P. acnes

This brief article presents a series of three cases of late capsular block syndrome (CBS) in which the milky fluid behind the IOL was aspirated from the capsular bag. The bacterial culture identified two of the cases as Propionibacterium acnes (P. acnes). All three eyes were completely quiet, without any clinical evidence of inflammation. The authors say that these cases call into question the role of P. acnes as a pathogen in late CBS and whether antibiotic therapy, topical or intravitreal, is actually indicated. They conclude that these cases demonstrate that late CBS may be successfully treated with Nd:YAG capsulotomy, but caution is warranted, as there may be a slight risk of endophthalmitis.

The authors note that P. acnes is classically associated with chronic endophthalmitis, in which patients present with symptoms of anterior uveitis and plaque is seen on the posterior lens capsule. This stands in contrast to the three eyes in the study. The authors propose that the pronounced inflammatory reaction seen in chronic endophthalmitis secondary to P. acnes is attributable to the access of the organism to the anterior chamber, allowing the eye to react with an inflammatory response. They say that in late CBS, there is an absence of inflammation, as the P. acnes in the turbid fluid is sequestered within the capsular bag due to the tight seal of the anterior capsule to the IOL. They note that when this type of case is treated with an Nd:YAG posterior capsulotomy, the milky fluid can be visualized tracking into the vitreous cavity. The authors say that have not yet observed inflammation or endophthalmitis in such cases.

They report that in their experience with other such cases that were treated with an Nd:YAG laser, this turbid fluid, with its debris, seemed to clear quite effectively from the vitreous cavity without consequence. They propose that this lack of inflammation is due to a low bacterial count with a prolonged doubling time of P. acnes or perhaps the oxygenated vitreous serving as a poor culture medium for this anaerobic species. Alternatively, they say the anterior segment inflammation seen in chronic endophthalmitis may be attributable to an immunologic phenomenon associated with P. acnes infection.