Monocular Reading Acuity Associated With Visual Function, Disease Severity

Monika Fleckenstein, MD

A recent study aimed to evaluate and identify the structural and functional determinants of monocular reading performance to evaluate reading performance in geographic atrophy (GA) and examination of binocular inhibition of reading performance in patients with GA, secondary to age-related macular degeneration (AMD).

The team, led by Monika Fleckenstein, MD, John A. Moran Eye Center, observed an association between monocular reading acuity and speed with established visual function and a measurement of disease severity.

Methods

Investigators performed a non-interventional, prospective natural history study entitled “Directional Spread in Geographic Atrophy'' at the Department of Ophthalmology at the University Hospital in Bonn, Germany.

Patients were enrolled in the study from June 2013 - June 2016 if they had GA in both eyes and were aged 55 years or older.

Moreover, BCVA, low-luminance visual acuity (LLVA), and reading performance were assessed using the Early Treatment Diabetic Retinopathy Study (ETDRS) and Radner charts. Additionally, the logarithmic scale is given as logarithm of reading acuity determination (logRAD).

Further, longitudinal fundus autofluorescence and infrared reflectance images were semi automatically annotated for geographic atrophy. Then, an extraction of shape-descriptive variables was collected.

Investigators applied linear-mixed effects models to associate variables in comparison with reading performance using least absolute shrinkage and selection operator (LASSO) regression.

Findings

At baseline, a total of 150 eyes of 85 participants were included, with a mean age of 77.9 years and 60% (n =  51) women. Participants had a mean reading acuity of 0.90 (0.40 - 1.30) logRAD with a reading speed of 52.8 (0 - 123) words per minute monocularly.

The multivariable analysis showed BCVA, GA in central subfield, foveal sparing, the GA in the inner-right ETDRS subfield, and the LLVA showed the strongest association with reading acuity (cross-validated R2 = 0.69).

Additionally, for reading speed, the relevant variables were best-corrected visual acuity, LLVA, area of geographic atrophy in the central ETDRS subfield, in the inner-right ETDRS subfield, and in the inner-upper ETDRS subfield (cross-validated R2 = 0.67).

A total of 75 participants with a median of 1 follow-up visit were included in the longitudinal data with no noticeable change in reading acuity and reading speed over time.

Then, in the longitudinal multivariable analysis, BCVA, foveal sparing, GA in central and inner-right ETDRS subfield, and LLVA showed the most associated variables of reading acuity (cross-validated R2 = 0.73). Age and follow-up time were eliminated in LASSO.

Similarly, for reading speed, BCVA, LLVA, foveal sparing, GA in inner-right and inner-upper ETDRS subfield were the most relevant variables (cross-validated R2 = 0.70). Age and follow-up time were eliminated again.

In addition, binocular reading acuity was influenced by the better seeing eye (0.94 logRAD/ logRAD; 95% CI, 0.91 - 0.97) and worse-seeing eye (0.74 logRAD/logRAD; 95% CI, 0.63 - 0.85).

Investigators noted the binocular reading performance has no noticeable difference compared with reading performance in the better-seeing eye in patients with GA.

Takeaways

The team noted that the data supports reading performance as a function outcome measure in interventional clinical trials.

“Particularly in eyes with foveal sparing, assessment of reading speed may provide additional relevant functional information beyond mere BCVA,” investigators wrote.

The study, “Association of Reading Performance in Geographic Atrophy Secondary to Age-Related Macular Degeneration With Visual Function and Structural Biomarkers,” was published online in JAMA Ophthalmology.