Abstract
Purpose :
Age-related macular degeneration (AMD) impairs several aspects of face perception, including face discrimination (identify differences between faces) and face recognition (recognize a previously-viewed face). Both involve processing of face identity, but it is unclear if AMD impairs one more than the other. We aimed to quantitatively compare the effect of AMD on two face perception tasks: one with a memory requirement (recognition) and one without (discrimination).
Methods :
16 patients with non-exudative AMD (VA = 0.12 to 0.6 LogMAR) and 16 age-matched controls (-0.18 to 0.06) completed two computerised face tests. The discrimination task presented four simultaneously-visible faces and required participants to identify the odd-one-out. The recognition task asked participants to identify a previously-viewed face from four alternatives. Both tests measured the face threshold- the minimum difference required between identities for either reliable discrimination or recognition. Thresholds were measured separately for full-faces, internal features (eyes, mouth and nose) and external features (head and hair).
Results :
Relative to controls, discrimination (1.71X) and recognition (1.66X) thresholds for full-faces were significantly higher (i.e. poorer sensitivity) in patients with AMD (both p<0.001). Thresholds measured with the discrimination and recognition tests were equivalent (p<0.001). Compared to the full-face condition, the difference in thresholds between controls and patients with AMD was significantly greater when only the internal features were visible (p<0.001). Relative to controls, thresholds for the internal features were 2.24X poorer in patients with AMD. External feature performance was impaired to a lesser extent (1.62X).
Conclusions :
AMD impairs both face discrimination and recognition. Face recognition performance (significant memory demand) was equivalent to that on a memory-free discrimination task. Our data indicate that the severity of the face perception impairment in AMD is dependent on the face information available, rather than task memory demands. Specifically, patients with AMD demonstrated the most severe impairment when only the internal features were visible. Overall, these results suggest that impaired encoding of visual information- particularly that from the internal features- underlies the difficulties that patients with AMD experience with both face discrimination and recognition.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.