Objective: To describe pupillary block glaucoma in phakic patients undergoing vitrectomy and 5000 centistoke silicone oil injection.

Methods: Observational case reports. Methods: Vitrectomy and higher-viscosity silicone oil injection was performed in two phakic patients with proliferative diabetic retinopathy.

Results: Both patients developed a pupillary block in the early postoperative period (1 week and 1 month after surgery). Unnoticed zonulysis during surgery, thought to be the main contributory cause, allowed access of the silicone oil between the iris and the lens. Although higher-viscosity silicone oil was used in both cases, an acute glaucoma developed. An inferior iridotomy was performed, resulting in a temporary resolution of the pupillary block.

Conclusions: Vitreoretinal surgeons should be aware of silicone-induced pupillary block glaucoma in phakic eyes, even when higher-viscosity silicone oils are used.