Abstract
Abstract: :
Purpose: Plastic visors offer both face and eye protection while playing sports. Standards for peripheral visual fields for these visors have been developed using a mechanical headform, a collimated light source, and photosensors in the primary gaze position. To date, visors have not been tested using human subjects and conventional perimetry. Furthermore, visual fields in non-primary gaze positions have received little attention. Hockey players frequently assume an elevated gaze position in combination with forward flexion of the neck. Our study measures the change in the superior visual field that individuals experience while wearing a visor and maintaining 15 degrees of gaze elevation. Methods: The right eyes of 8 adults wearing a hockey helmet were tested using standard Humphrey automated perimetry. Subjects were tested with and without a visor. The order of testing conditions was counterbalanced across subjects. Subjects were 19 to 44 years of age and had no prior ocular history. The same visor and design of helmet were used for all of the tests. Helmets were fitted according to industry recommended guidelines. The head was positioned in the perimeter such that there were 15 degrees of forward neck flexion and 15 degrees of gaze elevation. Automated threshold static perimetry was performed using the central 30-2 testing paradigm on the Humphrey field analyzer. The reliability of fixation during the tests was monitored both manually and by blindspot mapping. Results: Visual fields measured in upgaze with the visor consistently showed threshold depressions in the superior quadrants compared to visual fields in upgaze without the visor: mean difference 174dB (range 87-317dB; p = 0.008, two sided sign test). For all subjects, fixation losses, false positive errors, and false negative errors met conventional reliability criteria. Conclusion: Moderate relative upper scotomas occur when a hockey visor is worn and gaze is directed upward. This study provides the first visual field data from humans wearing hockey visors. The study will also compare other commonly used visors for the purposes of understanding optimal design characteristics.
Keywords: 511 perimetry • 624 visual fields