Researchers assessed the long-term outcomes of uveitic glaucoma in eyes undergoing systemic therapy or fluocinolone acetonide implant.
Study design
This study was a prospective follow-up of the Multicenter Uveitis Steroid Treatment (MUST) clinical trial in which patients were randomized to systemic therapy or fluocinolone acetonide implant for intermediate uveitis, posterior uveitis and panuveitis. Of the 255 patients enrolled, 232 (405 eyes) were included in this analysis. Stereo fundus photographs were collected at baseline, 3 months, 6 months and then annually during the MUST and follow-up studies, followed by a return to semiannual checkups 2 years into the follow-up study. Patients were followed for up to 10 years after enrollment. At 2 years, images showing change in cup-to-disc ratio were referred to the MUST glaucoma outcomes committee to determine if glaucoma was present based on photos, visual fields and IOP measurements. The outcomes measured included cup-to-disc ratio, visual field mean deviation (MD) and pattern standard deviation, best corrected visual acuity and IOP.
Outcomes
In an intention-to-treat analysis, 36% of eyes receiving an implant and 15% of those receiving systemic therapy developed glaucoma. In an as-treated analysis, 40% of eyes in the implant group and 8% in the systemic treatment group developed glaucoma. In addition, 38% of eyes assigned to systemic treatment but received the implant during follow-up developed glaucoma at a median of 2.8 years. Additional risk factors for glaucoma were Black race, use of IOP medications at baseline and higher cup-to-disc ratio. Elevations in IOP after starting uveitis treatment was also a strong predictor of glaucoma development. In the MUST study, 45% of cases in the implant group required incisional surgery to lower IOP within 7 years.
Of the 112 eyes that developed glaucoma, the median follow-up after glaucoma diagnosis was 4.5 years. After diagnosis, the average cup-to-disc ratio increased from 0.40 to 0.58, MD declined from -8.5 dB to -13.3 dB and mean BCVA decreased by 1 line. Fifteen eyes sustained a 6-dB or greater decline in MD and 6 sustained severe visual field loss to MD of -25 dB or less; 5 of the 6 eyes were in the implant group. None of the patients progressed to cup-to-disc ratio of 0.9 or worse.
Limitations
Eyes in the implant group had worse baseline MD and visual acuity and tended to lack cup-to-disc ratio assessments at baseline; 24% of eyes had ungradable cup-to-disc ratio at baseline. Corneal thickness was not assessed. In addition, patients had noncontinuous assessments of glaucoma status and measurements of outcomes along with varying follow-up intervals.
Clinical significance
The incidence of IOP elevation and glaucoma diagnosis rises over time in eyes with intermediate uveitis, posterior uveitis and panuveitis. It is very important to frequently monitor patients with uveitis for development of glaucoma. Patients with severe IOP elevation after receiving a steroid implant would benefit from early incisional surgery to prevent glaucomatous damage since IOP elevation long proceeds identification of glaucomatous damage.