Disposable Printed CamBlobs Charts for Measuring Contrast Sensitivity in Patients With Glaucoma

Contrast sensitivity (CS) is lowered in glaucoma. We aimed to assess whether a simple inexpensive CamBlobs CS test is just as effective as an established Pelli-Robson CS chart in assessing CS in people with glaucoma.

This study included two-groups of participants (27 no ocular disease and 23 glaucoma patients) who underwent CS testing using CamBlobs chart and a Pelli-Robson chart in each eye. Agreement and reliability between CamBlobs and Pelli-Robson charts were examined using Bland-Altman plots and receiver operating characteristic (ROC) curves to assess the diagnostic test accuracy. Visual field data were also obtained and compared with CS data from both charts.

A total of 54 eyes of control and 44 eyes of glaucoma patients were included. There were significant differences in CS between the control and glaucoma groups measured by the CamBlobs chart (p < 0.001) and also Pelli-Robson chart (p < 0.001). The area under the ROC-curve (AUC) for CamBlobs was 0.85 (p < 0.001) with sensitivity at 68.2% (95% CI 53.7%-80.6%) and specificity at 85.2% (95% CI 74.2%-92.9%), and for Pelli-Robson, the AUC was 0.88 (p < 0.001) with sensitivity at 93.2% (95% CI 83.3%-98.3%) and specificity at 66.7% (95% CI 53.5%-78.3%) for differentiating people with glaucoma and control by measuring CS. The correlation between mean deviation of the visual fields and CamBlobs chart log CS was r = 0.59 (p < 0.001), and with Pelli-Robson chart was r = 0.65 (p < 0.001).

CamBlobs charts are comparable to Pelli-Robson CS charts for assessing CS in people with glaucoma. CamBlobs offer a simple, portable method for CS testing beyond conventional clinical settings.