PURPOSE

To assess the diagnostic utility of dark adaptometry (DA) rod intercept time (RIT) to differentiate age-related macular degeneration (AMD) from central serous chorioretinopathy (CSCR).

DESIGN

Retrospective consecutive case series.

PARTICIPANTS

Consecutive patients with a clinical diagnosis of AMD or CSCR who were ≥50 years of age.

METHODS

The study included patients who had completed a DA study in ≥1 eye measured at 5° superior to the fovea on the retina. All patients underwent a comprehensive retina examination, including OCT assessment of the macula.

MAIN OUTCOME MEASURES

Patients were classified based on their RIT, with an RIT >6.50 minutes considered a delay.

RESULTS

The study included 67 patients with AMD and 25 with CSCR. Patients with AMD tended to be older (73.8 ± 8.9 years vs. 65.0 ± 7.2 years, < 0.001) and were more likely female (53.7% vs. 28.0%, = 0.049) compared with their CSCR counterparts. Additionally, patients with AMD tended to exhibit poorer vision in both their better-seeing (logarithm of the minimum angle of resolution 0.14 ± 0.13 vs. 0.08 ± 0.13, = 0.057) and worse-seeing (logarithm of the minimum angle of resolution 0.48 ± 0.47 vs. 0.26 ± 0.25, = 0.028) eyes. Rod intercept times were slower in patients with AMD compared with CSCR, both in the faster-adapting (12.44 ± 6.96 minutes vs. 4.01 ± 1.28 minutes, < 0.001) and slower-adapting (13.06 ± 6.67 minutes vs. 4.95 ± 1.78 minutes, < 0.001) eyes. Using a delayed RIT in the faster-adapting eye to classify patients with AMD versus CSCR showed excellent performance with a sensitivity of 79.1% (95% confidence interval [CI]: 67.4%-88.1%) and perfect specificity of 100.0% (95% CI: 86.3%-100.0%), yielding an accuracy of 97.4% (95% CI: 91.7%-99.6%). After adjusting for age, sex, and visual acuity, RIT in the faster-adapting eye remained an independent predictor of AMD versus CSCR.

CONCLUSIONS

Prolonged dark adaptation, indicated by a longer RIT, is capable of distinguishing individuals with AMD from CSCR, 2 conditions that share similar fundus features. Future investigations are warranted to assess the effectiveness of this noninvasive technique for AMD screening.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.