Development and Validation of a Mobile Application to Detect Visual Dysfunction Following Mild Traumatic Brain Injury

Following mild traumatic brain injury, visual dysfunction is a common occurrence, yet the condition often goes undiagnosed. A mobile application was developed to measure aspects of visual acuity and oculomotor function. The aim of this project was to validate the newly developed suite of outcomes conducive for use in the field to detect visual dysfunction.

A custom mobile application was developed on an Apple iPad using iOS operating system software version 11.0 in Objective C to measure near point of convergence (NPC), distance visual acuity, reading fluency, and self-rated convergence insufficiency (CI). To determine construct validity, 50 healthy young adults were administered NPC and distance visual acuity assessments using the iPad and standard clinical approaches. A ruler measurement was obtained simultaneous to the iPad NPC measurement to determine measurement accuracy. All testing was administered by a licensed optometrist and the order of testing (iPad versus clinical) was randomized.

The correlation coefficient between the iPad and clinical measurements of NPC was 0.893, while iPad and ruler measurement was 0.947. Modest accordance was found between iPad and wall chart measures assessing distance visual acuity. A ceiling effect was evident with use of a wall chart to determine distance visual acuity. Healthy young adults scored a mean (SD) of 13.0 (7.4) on the Convergence Insufficiency Symptom Survey. Reading fluency was highly variable with a mean (SD) of 291 (119) words per minute.

iPad measures of NPC were highly correlated with clinical measures, while visual acuity measured with the iPad showed modest correlation. Nonetheless, the suite of visual assessments provide value as screening tools, and when used in combination with reading fluency assessment and self-reported CI may be effective in identifying visual dysfunction following mild traumatic brain injury.