Abstract
Purpose :
Screening techniques such as finger count confrontation (FC) testing are routinely used as a rapid preliminary method for ruling out defects in the visual field (VF). Prior studies have evaluated the limited sensitivity of this test in patients with glaucoma, optic nerve disease, and neurological conditions using 24-2 or 30-2 static perimetry (SP) as the standard. Conditions such as retinitis pigmentosa (RP) also cause significant changes to a patient’s VF with different patterns of loss. Additionally, 30-2 or smaller SP represents less than 22% of the normal field of vision and may not accurately capture all defects. This study assesses the accuracy of FC testing of VFs in comparison to full-field SP in patients with RP.
Methods :
FC testing was performed by presenting 1 or 2 fingers in each of the 4 quadrants of a patient’s VF, approximately 30 degrees and 66 cm away from fixation, with the fellow eye occluded. Incorrect responses were deemed an abnormal and positive result for that quadrant. Octopus SP was then conducted using a 30-2 grid followed by a modified radial pattern 185-point grid that tested the VF outside of the central 30 degrees. Each SP quadrant was analyzed for significant sensitivity deviations, defined as at least 3 significant (p < 0.05) abnormal points. Corresponding FC and SP quadrants were compared and determined as true or false positive or negative responses.
Results :
An initial sample of 5 eyes (5 patients) was analyzed. The mean (SD) age of patients was 46.8 (25.1). All 20 quadrants were significantly abnormal on SP. The FC test detected abnormalities in 12 of the 20 quadrants for a sensitivity of 60%. All patients with a peripheral quadrant defect also had a defect in the corresponding central field quadrant.
Conclusions :
The modest sensitivity indicates that a positive FC response is likely to signify true VF loss. This sensitivity finding is smaller than results from prior studies and suggests that FC testing may be less effective at detecting VF loss due to RP compared to loss due to optic nerve or neurological changes. Further data collection is necessary, especially in patients without field loss, to determine specificity.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.