Differential Impact of Intraocular Pressure Lowering on Glaucoma Progression in African- and European-Descent Individuals.

PURPOSE: To determine whether the relationship between intraocular pressure (IOP) and the rate of visual field progression (ROP) differs according to ancestry.

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 794 participants (1382 eyes) from the African Descent and Glaucoma Evaluation Study (ADAGES), including 478 glaucoma patients (696 eyes) and 555 glaucoma suspects (838 eyes). Participants self-identified as being of African descent (AD, n = 287) or European descent (ED, n = 507).

METHODS

A sliding-window framework was used to estimate moment-specific ROP from longitudinal visual field data. Multivariable mixed-effects linear regression was used to assess the main and interactive effects of race, IOP, age, gender, central corneal thickness, and mean deviation on ROP. Stratified analyses were performed to evaluate effect modification by ancestry, age, IOP, and disease severity.

MAIN OUTCOME MEASURES: ROP per millimeter of mercury (mm Hg) IOP change (dB/y/mm Hg).

RESULTS

In glaucomatous eyes, a higher IOP was associated with faster progression (β = -0.025 dB/y per mm Hg; P < .001). Race modified this relationship (race × IOP interaction β = 0.023 dB/y per mm Hg; P = .012), with steeper IOP-ROP slopes in AD (-0.014 dB/y per mm Hg; P < .001) than ED (-0.003 dB/y per mm Hg; P > .05) individuals. The difference was most pronounced in older and more advanced eyes; in severe glaucoma, each 1-mm Hg IOP increase corresponded to an increase in ROP (-0.044 dB/y in AD vs -0.032 dB/y in ED eyes; both P < .001). Racial differences in IOP sensitivity attenuated after trabeculectomy, and ROP in glaucoma suspects had little dependency on IOP.

CONCLUSIONS

Glaucoma progression in response to IOP alteration differs between individuals of AD and ED, particularly at older ages and with greater disease severity. Reconsideration of IOP-targeting strategies that incorporate ancestry, age, and disease severity may be beneficial to reduce disparities in glaucoma outcomes in the future.