RABIN CONE CONTRAST SENSITIVITY TEST REPEATABILITY IN HEALTHY PATIENTS OF DIFFERENT AGE GROUPS

Abstract

Purpose : Visual performance can be measured by different tests, such as contrast sensitivity (CS). The Rabin Cone Contrast Sensitivity Test (RCCST [Innova Systems]) is an easy way to evaluate CS. To our knowledge, this has not been validated before in subjects with apparently normal visual acuity (VA). The purpose of our study was to validate the RCCST's CS test in ophthalmologically healthy individuals to determine changes in CS with age and assess test-retest variability.

Methods : This was a retrospective, observational and comparative study performed in the Retina Department of the Asociación Para Evitar la Ceguera en México (APEC). Volunteers agreed to participate in CS testing and signed informed consent. The project was approved by the Institutional Review Board, and adhered to the Declaration of Helsinki.
Patients were aged between 18 and 65, ophthalmologically healthy with a refractive error between -2.00 to +2.00 D, and best corrected VA ≥20/20. Each subject was evaluated for CS 3 times to determine intraobserver repeatability (test-retest reliability). Subjects were grouped by age: 18-29; 30-39; 40-49; 50-60. Comparison between age subgroups was performed. Cronbach’s alpha and Intraclass Correlation Coefficient (ICC) were used to measure correlation between results. Kruskal-Wallis test (KW) was performed to determine differences among subgroups. Spearman's Correlation Coefficient (SCC) was performed to detect correlation between age and CS.

Results : 114 subjects were studied, consisting of 58 women and 46 men, with a mean age of 33.72, standard deviation (SD) 12.32, range 18 - 60. Mean CS was 1.61 CS logarithmic scale (CSLS), 0.10 SD, 95% confidence interval (CI) 1.59 - 1.63 (range: 1.25 - 1.98). Cronbach’s alpha resulted in a correlation of 0.725; ICC for average measures resulted in a correlation of 0.726, 95% CI 0.626 - 0.803 (P< 0.001). Hence, both tests returned “good” reliability of the system.
CS means by subgroups are shown in Table 1. KW resulted in a statistically significant difference between groups: Chi-squared of ranks=14.48, P=0.002. SCC between CS and age resulted in a correlation of -0.355 (P< 0.001) (Graph 1).

Conclusions : Repeatability of CS measurement by RCCST resulted in a “good” correlation. Differences among age groups existed, with a lower CS for older individuals. Therefore, we consider that CS can be accurately measured using the RCCST in a subset of healthy subjects.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.