Clinically diagnosed Posner–Schlossman syndrome in a patient with prior implantable collamer lens implantation: a case report

Elevated intraocular pressure (IOP) is a recognized complication after implantable collamer lens (ICL) implantation. Early postoperative IOP elevation may result from retained ophthalmic viscosurgical material, corticosteroid response, pupillary block, or other postoperative factors. However, recurrent unilateral ocular hypertension developing long after surgery may also reflect conditions independent of the implanted lens, complicating the differential diagnosis. We report a patient with prior bilateral ICL implantation who developed recurrent unilateral ocular hypertension approximately 2 years later and was clinically diagnosed with Posner–Schlossman syndrome (PSS). A 21-year-old man underwent uneventful bilateral toric ICL implantation for high myopia. During the early postoperative period, both eyes developed transient corticosteroid-associated ocular hypertension that resolved after corticosteroid withdrawal and IOP-lowering treatment. At 23 months after surgery, he experienced the first episode of acute unilateral ocular hypertension in the right eye, followed by a second episode 5 months later. During the second episode, the IOP reached 49 mmHg. Evaluation showed a well-centered ICL, quantitative vault measurements of 678 μm in this eye, widely open anterior chamber angles with only minimal trabecular pigmentation, and no evident structural glaucomatous damage. Careful slit-lamp examination revealed fine-to-medium-sized keratic precipitates with mild anterior chamber inflammation. The overall clinical presentation was consistent with clinically diagnosed PSS. Treatment with topical prednisolone acetate and IOP-lowering medications rapidly reduced the IOP and relieved the symptoms. On treatment day 17, the IOP increased again to 58 mmHg after corticosteroid re-exposure; given the previous bilateral corticosteroid-associated IOP elevation and normalization of IOP after prednisolone withdrawal, this episode was considered more consistent with a corticosteroid response than with recurrent PSS activity. Aqueous humor polymerase chain reaction (PCR) testing was not performed; therefore, a cytomegalovirus (CMV)-associated etiology could neither be confirmed nor excluded. In patients with prior ICL implantation who develop late recurrent unilateral ocular hypertension, careful anterior segment examination for keratic precipitates and a systematic differential diagnosis are important for recognizing inflammatory causes such as PSS rather than attributing the IOP elevation solely to the implanted lens.