Age-related changes in contrast sensitivity function under different illumination conditions.

Clinical relevance: Age-related baseline data are important in clinical optometry as a reference against which vision abnormalities can be diagnosed.

Background: Contrast Sensitivity Function (CSF) is important for detecting age-related vision diseases. However, existing studies often overlook elderly populations under a range of testing situations, thus potentially delaying the diagnosis. Establishing age-specific data under different illumination and glare conditions may help in the early identification of certain eye diseases. The aim of the present study was to evaluate CSF in healthy individuals aged 50-80 years under a range of illumination and glare conditions to generate new and extended normative data for the Functional Acuity Contrast Test.

Methods: CSF was assessed under photopic and mesopic conditions, with two levels of glare: low glare (G1) and high glare (G2). Best-corrected visual acuity (BCVA) was assessed using the ETDRS chart. Participants were divided into three age groups: 50-59 years (P1), 60-69 years (P2), and 70-80 years (P3).

Results: A total of 90 participants were included. A significant decline in BCVA was noted for those in their 50s and 60s. Photopic CSF was best with G1. An age-related decline in photopic CSF, particularly at mid- to high-spatial frequencies, was more pronounced with G2. Mesopic CSF decreased under both glare conditions (G1 and G2) and with increased age, with lower sensitivities observed, except at 1.5 c/deg. CSF variations were also associated with BCVA, age, and sex.

Conclusions: CSF declined with age, especially under mesopic conditions. These new findings suggest that testing of mesopic CSF may be a valuable tool for early detection of age-related eye diseases.