Wet vs. Dry Age-Related Macular Degeneration in Patients With Central Field Loss :
Different Effects on Maximum Reading Speed
Aurélie Calabrèse (1), Jean-Baptiste Bernard (1), Louis Hoffart (1,2), Géraldine Faure (2), Fatiha Barouch (2), John Conrath (1,2), Eric Castet (1)
1. Université Aix-Marseille II, CNRS – Institut de neurosciences cognitives de la Méditerranée INCM – UMR 6193 ; 2. Department of Ophthalmology, La Timone hospital, France

Abstract
Purpose : To compare reading performance between wet and dry age-related macular degeneration (AMD) patients with central field loss, while adjusting for relevant clinical factors.
Methods : Linear mixed-effects (lme) analyses were performed on a dataset initially collected to assess the effect of interline spacing on Maximum Reading speed (MRS). Monocular reading speed was measured in 90 eyes (64 dry and 26 wet) from 61 patients with AMD. French MNRead-like sentences were presented on a monitor with decreasing letter sizes at three different interline spacings (0.79X, 1X and 2X the standard). From these data, MRS was calculated for the 3 interline spacings. These 3 repeated measurements justified the use of lme analysis. Microperimetry (MP1) was used to determine the characteristics of scotomas (size, position, shape, …), the position of the Preferred Retinal Locus used during fixation (fPRL), and the distance between fPRL and fovea. Patients were included in the analysis only if they had an absolute macular scotoma including the fovea.
Results : MRS is significantly smaller for dry eyes than for wet eyes even when adjusting for the clinical factors collected in our study: it is smaller (- 31 %) in a model where only significant main effects are included. A consistent interaction, although only marginally significant, is found between the wet/dry and fPRL location factors: notably, the wet/dry difference is smaller for the left-field fPRL than for the lower-field fPRL. In addition, the predominant fPRL is in the lower field for wet eyes whereas it is in the left field for dry eyes.
Conclusion : The large wet/dry difference in MRS cannot be accounted for by any of the factors measured in our work. However, the interaction with the fPRL factor suggests that reading strategies are more optimal for wet patients. The wet/dry difference might be related to the different time-courses of disease progression in each AMD type (sudden onset for wet disease vs. slow evolution for dry disease).