Abstract
Purpose :
Dark adaptometry and electroretinography are currently used to evaluate nyctalopia; they present many challenging barriers in young children due to non-compliance and complexity. A more affordable, convenient and age-appropriate screening tool was developed; a book consisting of black photo paper with pictures of animals in a UV-activated fluorescent ink. This study aims to evaluate the hypothesis that the book will be an accurate and effective screening tool for nyctalopia.
Methods :
During the development of this tool, a 3-log neutral density filter and a spectroradiometer were used to assess luminance over a range of fluorescent ink densities to target scotopic vision. The intensities incorporated were 5, 10, 25, 50, and 100%. Subjects with rod dystrophies and healthy controls were recruited.
Following 15 minutes of dark adaptation, each eye was tested separately while covering the other. Fluorescent ink was activated by a UV flashlight. Subjects were asked to identify the animal(s) pictured on each page or to outline an image if fluorescence was recognized but no identification was made. Participants were also tested with dark adaptometry to compare the night blindness measured by the two techniques.
Results :
Twenty controls (40 eyes) and twelve subjects (24 eyes) were recruited. Of the controls, 37 (92.5%) were able to first recognize fluorescence at 10% intensity or lower and the remaining 3 (7.5%) first recognized fluorescence at 25%.
Of the subjects, none were able to recognize fluorescence at 5% intensity, only 1 eye (4%) first recognized fluorescence at 10%, and the remaining 23 (96%) first recognized fluorescence at 25% intensity or higher; of those, 1 eye (4%) was unable to recognize any fluorescence, 13 eyes (54%) first recognized fluorescence at 25%, 5 eyes (21%) at 50%, and 4 eyes (17%) at 100%. Stimulus intensity recognition with dark adaptometry at the 15-minute mark ranged from -54dB to -62dB in healthy controls vs -12dB to -60dB in affected subjects.
Conclusions :
Subjects with rod dystrophies requiring a higher stimulus intensity with dark adaptometry were noted to require higher intensities of fluorescence at first recognition compared to healthy controls, which supports the use of the book as an evaluation tool. This fluorescence testing needs further validation using a larger sample in order to establish a correlation between stimulus intensity and fluorescence intensity at first recognized image.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.