Abstract
Purpose :
Although post-operative hypotony after glaucoma filtering surgeries is relatively common, many ophthalmologists argue that ocular hypotony is relatively inconsequential. The occurrence of corneal ectasia and hydrops have been described to occur in the setting of hypotony associated with chronic uveitis. The purpose of this study is to describe corneal topographical changes and ectasia occurring in patients who experienced hypotony after glaucoma filtering procedures.
Methods :
Prospective case series on adults who presented to the University of Illinois glaucoma service from October 2016 to October 2017 who had undergone glaucoma drainage surgeries with at least 3 months of ocular hypotony (IOP readings of 5mm Hg or less). Patients who had undergone previous corneal surgeries, had a history of corneal ectasia prior to glaucoma surgeries, or had a history of uveitis were excluded. Slit lamp photography, corneal topography, and anterior segment optical coherence tomography were obtained from all patients.
Results :
A total of 10 eyes of 8 patients were included. Significant associations between age, preoperative central corneal thickness and the development of irregular corneal astigmatism were found(p<0.05). Older patients(age>80) with thin corneas(CCT<520) developed irregular astigmatism more frequently. Significant change in best-corrected spectacle visual acuities were found in patients who developed irregular astigmatism after surgery (mean logMAR 0.53 vs. 0.90, p=0.02). Three of the 10 eyes also developed superior steepening and paracentral thinning in an ellipsoid pattern associated with corneal sutures in the setting of hypotony(Figure 1).
Conclusions :
We illustrate the development of decreased visual acuity associated with irregular corneal astigmatism and the potential for the development of irreversible corneal ectasia as complications of persistent hypotony post glaucoma surgeries. Evaluation with corneal topography or rigid contact lens overrefraction may be warranted in hypotonous eyes with unexplained vision loss as subclinical corneal thinning, corneal ectasia and/or irregular astigmatism could be the cause.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.