The Scotopic Sensitivity Tester-1 and the detection of early age-related macular degeneration.

PURPOSE

Previous research shows that dark adaptation is a marker of early age-related macular degeneration (ARMD), even when visual acuity remains good. This study evaluates whether a commercially available, off-the-shelf device for measuring dark adaptation, the Scotopic Sensitivity Tester-1 (SST-1), which uses a full-field stimulus, detects early ARMD as defined by fundus appearance. Fundus appearance is the gold standard method for defining the presence of ARMD.

METHODS

Dark adaptation was measured using the SST-1 in 12 young adults (mean age 23 years), 17 old adults with normal retinal health (mean age 69) and 19 old adults with early ARMD (mean age 74). Normal retinal health and presence of early ARMD were defined by masked grading of dilated fundus photographs using the Wisconsin Age-Related Maculopathy Grading System.

RESULTS

Older adults in normal retinal health exhibited slower dark adaptation as compared with young adults. No difference in the rate of dark adaptation was found between early ARMD patients and older adults in normal retinal health.

CONCLUSIONS

Although the SST-1 differentiated between young and older adults, it failed to detect dark adaptation abnormalities in early ARMD when referenced against older adults in normal retinal health. This may be attributable to the full-field stimulation used by the SST-1, which may be better suited for characterizing retinal degenerations affecting large retinal areas than for focal macular diseases like ARMD.