Case report - Acute Corneal Subepithelial Hydrops (ACSH) during Micropulse Transscleral Cyclophotocoagulation (MPTSC)

To present an unusual intra-operative complication of micropulse transscleral cyclophotocoagulation (MPTSC).

A 72-year old Chinese gentleman, who had primary angle closure glaucoma and had received bilateral laser iridotomy, presented with progressive left eye blurred vision (visual acuity of 20/40 OD and 20/200 OS). Examination reviewed left eye central retinal venous occlusion. The intraocular pressure (IOP) was 19 mmHg OS and was on maximally tolerated topical medications. Four weeks later, the left eye was complication by neovascular glaucoma; the IOP was raised to 26 mmHg despite additional oral acetazolamide and remained elevated after pan-retinal photocoagulation as well as cataract extraction by phacoemulsification. MPTSC was performed 8 days after the phacoemulsification. During the procedure, a sudden protrusion was formed on the corneal surface. On-table examination with operating microscope and portable slit-lamp reviewed an intact corneal epithelium with a globular-shaped collection of fluid at the subepithelial layer - acute corneal subepithelial hydrops (ACSH). The anterior chamber was formed and the globe was intact. After approximately 10-15 minutes, the swelling spontaneously ruptured and became a corneal epithelial defect. The defect healed on the tenth day after the event with conservative management. There was no irreversible corneal damage and the patient subsequently underwent a successful second MPTSC of the left eye because of poorly controlled IOP.

ACSH is a possible intra-operative complication of MPTSC. We have proposed the possible mechanisms of ACSH. It is best to exercise caution when using MPTSC shortly after any incisional intraocular surgery.