PURPOSE. The "photo-stress test" uses a source or flash to create an after-image in patients suspected of maculopathy. Abnormal results are those in which recovery time is prolonged. The Eger Stressometer was developed to provide a more standard photo-stress test. This device utilizes a thyristor photo-flash, a digital timer and a built-in acuity chart to maximize the uniformity of test performance . The purpose of this study was to establish test reliability, age-related norms and to identify potential correlates for macular disease. METHOD. 87 subjects (20- 90 yrs.) were tested using the Eger Stressometer after obtaining informed consent. Subjects read the smallest line possible at 40 cm. The flash was then triggered at 15 cm. Recovery acuity was taken at 40 cm using the next higher line. The timer was stopped, and the recovery time established. Reliability was measured in 15 subjects in the 20 year age-range by repeating the test after a 20-minute delay. Age-related norms were established using data collected only from subjects without eye disease.
RESULTS. Test-retest reliability was strong (Intraclass Correlation Coefficient (ICC) =0.966) Age-related recovery time was shortest for the youngest age groups tested, increasing in a linear fashion 2.16 seconds per decade of age. The correlation of average data by decade was excellent as compared with a previously published study by Gomez-Ulla (Pearson Product-Moment = 0.946). A small number of subjects tested, who had signs of maculopathy, demonstrated recovery at 20-40% longer than the age-related norms.
CONCLUSIONS. The Eger Stressometer provides a reliable and easy method of photo-stress testing. Age-related recovery times increased linearly and correlated well with previously published data. Preliminary results show prolonged photo-stress recovery in cases with macular changes. The Eger Stressometer is a useful screening tool for normal photo-stress recovery and may prove useful to monitor macular changes in patients with degeneration.