Relative Ellipsoid Zone Reflectivity Significantly Reduced Over Time in iAMD Eyes

Chi D. Luu, PhD

New research reports the relative ellipsoid zone reflectivity (rEZR) is significantly reduced in subjects with intermediate age-related macular degeneration (iAMD) over a 3-year period.

The findings suggest both the presence and increasing extent of coexistent reticular pseudodrusen (RPD) at baseline were associated with a faster rate of decline.

“These findings warrant further studies to understand the value of rEZR as a biomarker of AMD progression,” wrote study author Chi D. Luu, PhD, Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital.

Luu and colleagues indicate that rEZR has been reported to be reduced in patients with iAMD, but the longitudinal changes seen in rEZR has remained unknown. As a result, they set out to investigate the natural history of rEZR in iAMD and its association with risk factors for disease progression, including the presence or extent of drusen volume, RPD, and pigmentary abnormalities (PAs).

The longitudinal observational study included participants with bilateral large drusen. Investigators collected spectral-domain optical coherence tomography (OCT) images of both eyes from each individual every 6 months for 3 years. Then, with an automated rEZR determination approach, the average rEZR of the central 20° macula was calculated for each SD-OCT volume scan.

Meanwhile, linear mixed models were used to determine the rate of change in rEZR with age using cross-sectional data at baseline and over time using longitudinal data, as well as the interactions between the rate of rEZR changes with AMD risk factors at baseline. Main outcomes for the study included the relative ellipsoid zone reflectivity and its rate of change with age and over time.

The study included a total of 280 eyes from 140 subjects with bilateral large drusen. The cross-sectional findings showed that rEZR reduces with increasing age (‒8.4 arbitrary units [AUs] per decade; 95% confidence interval [CI], –11.5 to ‒5.2; P < 0.001).

Moreover, the longitudinal data show that rEZR declined at a rate of ‒2.1 AU per year on average (95% CI, –2.6 to –1.6 AU per year; P <.001). A larger RPD area (P = .042) at baseline was linked to a faster rate of rEZR decline over time.

On the other hand, the presence of PAs and the drusen volume at baseline showed no significant association with rEZR decline over time (P = .068 and P = .529, respectively).

The abstract, “Natural History of the Relative Ellipsoid Zone Reflectivity in Age-Related Macular Degeneration,” was published in Ophthalmology.