Corneal ectasia associated with postoperative hypotony.

Importance: Although post-operative hypotony is common, many ophthalmologists argue that ocular hypotony is relatively inconsequential and question its occurrence as a surgical complication. Corneal changes related to ocular hypotony has seldom been described.

Objective: To describe corneal topographical changes and ectasia occur in patients who experienced hypotony after glaucoma filtering procedures.

Design: Prospective case series on adults who presented to the University of Illinois glaucoma service from October 2016 to September 2017 who had undergone glaucoma drainage surgeries with at least 3 months of ocular hypotony.

Setting: Single, referral center.

Participants: Adults who had undergone glaucoma drainage surgeries with at least two separate post-operative intraocular pressure readings of 5 mmHg or less measured by Goldmann applanation tonometry in one or both eyes were included. Patient with less than 3 months of persistent hypotony and/or had undergone previous corneal surgeries, had a history of corneal ectasia prior to glaucoma filtering surgeries, or had a history of uveitis were excluded.

Intervention/exposures: Slit lamp photography, corneal topography, and anterior segment optical coherence tomography were obtained from all patients at the time of enrollment.

Main Outcomes: The development of irregular astigmatism on topography, corneal ectasia on OCT and changes in best-corrected spectacle visual acuity.

Results: A total of nine eyes of seven patients were included. Significant associations between age, thin central corneal thickness and the development of irregular corneal astigmatism were found (p<0.05). Irregular corneal astigmatism was associated with a decreased best-corrected spectacle visual acuity (p=0.02). We also report a case of bilateral corneal ectasia associated with corneal sutures in the setting of hypotony.

Conclusions And Relevance: We illustrate the development of decreased visual acuity associated with irregular corneal astigmatism and the potential for the development of irreversible corneal thinning as complications of persistent hypotony post glaucoma filtering surgeries.