Efficacy Comparison Of A Smartphone Application (Focus Up®) And Age-Based Method For Near Addition Power In Presbyopia: A Pilot Study

This study aims to compare the efficacy of a smartphone application with the Age-Based Addition Method in determining the power addition for presbyopic patients

A prospective cross-sectional pilot study was conducted at the Department of Ophthalmology, Siriraj Hospital, a tertiary care center, from April 2024 to February 2025. FocusUp^®* is a smartphone application designed for measuring presbyopia and evaluating symptoms of eyestrain. It has been approved by the Thai FDA as a medical device.

Presbyopic patients aged 40–80 years with best corrected visual acuity (BCVA) better than 6/7.5, spherical equivalent (SE) and astigmatism within ±1.00 diopter (D), no ocular pathology and no prior presbyopia correction except glasses were included. Distance and near BCVA were assessed using the Rosenbaum chart at 14 inches. Additional lens power was determined using a smartphone application, where participants adjusted their hand position until they could read the sample text. The obtained value was compared to the age-based method, which allowed ±0.50 D adjustments. Success was defined as reading at least three characters on the J1+ line. Measurement time for both methods was recorded. All procedures were performed by the same technician.

A total of 72 presbyopic patients were included, with a mean age of 58.5 ± 11.4 years. Median (IQR) distance visual acuity (logMAR) was 0.00 (0.00, 0.30) in the right eye and 0.00 (0.00, 0.14) in the left eye, while near visual acuity was 0.4 (0.06, 1.00) in both eyes. Median (IQR) SE was 0.00 D (-1.00 to 1.00) in the right eye and 0.00 D (-0.75 to 1.00) in the left eye. Although the age-based method had a higher success rate than the application (95.8% vs. 84.7%, P < 0.01), the application was faster (1.35 ± 0.32 vs. 1.81 ± 0.51 min, P < 0.01) but suggested lower added lens power (2.13 ± 0.06 D vs. 2.26 ± 0.07 D, P < 0.01). Among 11 discordant cases, two had identical added power values, while nine had discrepancies of 0.25–0.50 D.

The application improves the efficiency of determining additional lens power for presbyopia by providing a time-saving and easy-to-use method. It assists users, particularly those accustomed to ready to wear glasses, in selecting the appropriate lens power, thereby saving resources in remote areas with limited conventional measurement methods. However, further enhancements are necessary to improve its efficacy. Users can adjust the plus lens power within ±0.50 diopter range from the app's recommended value to achieve optimal near vision at a 14-inch working distance. *Copyright © 2023 Readsight Pro Co., Ltd.