Measuring visual acuity and spherical refraction with smartphone screens emitting blue light

Area of Science:

• Ophthalmology
• Optometry
• Biomedical Engineering

Background:

• Smartphone-based self-monitoring of spherical refraction can enable early intervention for myopia progression.
• A significant challenge is the distant far point (FP) in low myopia, hindering device interaction.
• This study introduces a novel method utilizing longitudinal chromatic aberration (LCA) to optically reduce the FP distance.

Purpose of the Study:

• To investigate the use of blue light's longitudinal chromatic aberration (LCA) to optically adjust the far point (FP) for smartphone-based myopia monitoring.
• To evaluate the accuracy of smartphone-based visual acuity and spherical refraction measurements compared to clinical standards.

Main Methods:

• Longitudinal chromatic aberration (LCA) was measured using subjective spherical refraction with blue and grey stimuli on OLED screens.
• Visual acuity (VA) was compared between smartphone-displayed blue optotypes and standard eye charts at 1.0m and 1.5m.
• Spherical over-refraction in blue light via smartphone was compared to clinical measurements using black and white optotypes at 6m.

Main Results:

• Mean LCA for blue OLED smartphone screens was -0.67 ± 0.11 D.
• No significant difference in VA was observed between smartphone blue optotypes and clinical eye charts (p > 0.05).
• The mean difference in spherical over-refraction between smartphone and clinical measurements was 0.08 ± 0.34 D.

Conclusions:

• Smartphones utilizing blue light are effective tools for detecting visual acuity and spherical refraction changes.
• This technology facilitates the monitoring of myopia progression.
• The optical adjustment of the far point using LCA improves the feasibility of smartphone-based eye examinations.