Sensitivity to Central Crowding for Faces in Patients with Glaucoma.

PRECIS Some patients with glaucoma report difficulties to recognize faces when they are far away. We show that this deficit could result from a higher sensitivity to crowding in central vision. PURPOSE to investigate whether face recognition difficulties reported by some patients with glaucoma result from a greater sensitivity to inner crowding in central vision. METHOD Seventeen patients with glaucoma and 17 age-matched normally sighted controls participated. An isolated mouth (uncrowded condition) or a mouth within a face (crowded condition) was randomly displayed centrally for 200 ms. For each condition, participants were asked to decide whether the mouth was closed or open. The stimuli were presented at three angular sizes (0.6°×0.4°, 1°×0.72°, and 1.5°×1.08°). Accuracy was measured. RESULTS Crowding affected performance differentially for patients and controls. Consistent with previous studies controls exhibited a "face superiority effect", with a better accuracy when the mouth was located within the face than when it was isolated . A sensitivity to crowding, reflected in a better accuracy with the isolated mouth, was observed in 10 out of 17 patients only for small images. Crowding disappeared for larger faces, as the facial features were spaced out. Five patients were not sensitive to crowding. Importantly, no difference was found between the two subgroups of patients (sensitive vs. non sensitive) in terms of Mean Deviation, contrast sensitivity, acuity, thickness of the RNLF or macular GCIPL. CONCLUSION An excessive sensitivity to central crowding might explain the difficulties in face perception and reading reported by some patients with glaucoma. The sensory or cognitive processes underlying this excessive sensitivity must be elucidated to improve central perception in glaucoma.