Preliminary Evaluation of a Mobile Device for Dark Adaptation Measurement

We evaluated the feasibility of a smartphone application-based dark adaptation (DA) measurement method (MOBILE-DA).

On a Samsung Galaxy S8 smartphone, MOBILE-DA presented a 1.5° flashing stimulus (wavelength = 453 nm) between -1.15 and -4.33 log candela (cd)/m² at 8° eccentricity using an adaptive staircase, and logged timing of user response (tapping on the screen) whenever the stimulus became visible (monocularly). In a dark room, the smartphone was placed ≈40 cm from the subject, and a white smartphone screen at maximum brightness (≈300 cd/m²) for 120 seconds was used for bleaching before testing. MOBILE-DA was evaluated in normally-sighted (NV) subjects (n = 15; age, 22-82 years). Additionally, a subject with myopic retinal degeneration (MRD; VA, 20/100; age, 62 years) and another with optic nerve atrophy (ONA; visual acuity [VA], 20/500; age, 40 years) were measured. Maximum test timing was capped at 20 minutes. Linear regression was performed to determine age-effect on DA parameters: rod-cone break time (t ) and test-time (t ). Use of the normalized area under the DA characteristics (AUC) as an outcome measure was explored.

For NV, the repeatability coefficients for t , t , and AUC were ±2.1 minutes, ±5.4 minutes, and 4.4%, respectively, and aging-related delays were observed (t , R ² = 0.47, P = 0.003; t , R ² = 0.34, P = 0.013; AUC, R ² = 0.41, P = 0.006). Compared to ONA and NV, DA was greatly prolonged in the MRD subject (52% larger AUC than the NV mean).

The age-effect was verified for MOBILE-DA measurements in NV subjects; impaired DA in a case with retinal-degeneration was observed.

This study establishes feasibility of the smartphone-based DA measurement method as a potential accessible screening tool for various vision disorders.