Microdot test of foveal function. A comparison with visual acuity at high and low contrast.
OBJECTIVE
To define normal values across age from novel computerized tests of foveal vision and to compare the findings with visual acuity (VA) at high and low contrast.


METHODS
Sixty-one healthy volunteers, aged 22-87, with subjectively normal vision participated in the study. The right eye from each subject was tested with Snellen letter VA at high contrast, at 10% contrast using the Tri-VA test and with the Rarebit Microdot Fovea Test (RMFT), in addition to biomicroscopy and fundus examination.


RESULTS
The median letter VA was 0.77 minimum angle of resolution (MAR; range 0.63-1.54) with a significant decline in letter VA with increasing age (r = 0.7, p < 0.001). The median Tri-VA resolution threshold at 10% contrast was 1.8 MAR (range 0.9-4.1) and a significant age effect (r = 0.7) was observed, most pronounced above 65 years. The median RMFT hit rate was 100% (range 97-100) in the age group below 65 years and 87.5% (range 34-98) in subjects older than 65 years.


CONCLUSIONS
The study shows a decline in foveal function with age with all three methods, reflecting the loss of neural detectors with increasing age. The hit rate to microdot stimuli appears to be a sensitive measure, which can be used for fine-graded evaluation of foveal function.
Malmer
L
L
Section of Ophthalmology and Vision, Department of Clinical Neuroscience, Karolinska Institutet, St Erik's Eye Hospital, S-112 82 Stockholm, Sweden.
Martin
L
L
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003196:Computer Graphics; D015350:Contrast Sensitivity; D005584:Fovea Centralis / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D012016:Reference Values; D012680:Sensitivity and Specificity; D012684:Sensory Thresholds; D014787:Vision Tests; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests / Q000379:methods