Online Circular Contrast Perimetry: Validity and Repeatability of Home Performance.

Abstract

Precis: Online Circular Contrast Perimetry (OCCP) offers clinically validated threshold perimetry to patients via a web-application from their own devices. This study evaluates the feasibility, repeatability and reliability of OCCP when performed in unsupervised home environments.

Purpose: To evaluate the feasibility, repeatability and reliability of online circular contrast perimetry (OCCP) when performed in unsupervised home environments on personal devices.

Patients and methods: 55 participants (20 control and 35 open-angle glaucoma patients) were recruited. Participants underwent baseline visual field testing using OCCP in a clinical setting, followed by weekly unsupervised home tests over six weeks on their personal computers. An online survey was completed afterwards. Global perimetric indices and reliability indices were compared between clinic-based and home-based tests and analyzed to assess the repeatability and reliability of OCCP at home. Rasch analysis assessed the psychometric properties of the survey and intergroup variability.

Results: No statistically significant differences were found in mean deviation (MD), pattern standard deviation (PSD), or visual index values between home and clinic tests (P>0.05), and these values did not significantly alter over the 6 weekly at-home tests. OCCP false positive and fixation loss responses were statistically higher at home compared to baseline (P=0.002 & P=0.001). Test-retest intraclass correlation coefficients for OCCP home use compared to in-clinic for MD ranged from 0.90 to 0.93, and for PSD ranged from 0.81 to 0.85. Bland-Altman analysis for MD revealed zero test-retest bias with limits of agreement ranging from ±5.28 to ±5.83 dB across the six weeks. The survey indicated high user satisfaction, however Rasch analysis revealed suboptimal precision and targeting.

Conclusions: OCCP retains a similar diagnostic accuracy and repeatability in home environments on personal devices compared to clinic-based environments and has the potential to be utilized as a remote tool for glaucoma screening and surveillance.