Background: Despite the potential for eye injury, most hockey players in the National Hockey League do not use a protective face shield. We examined the effect of a hockey visor and sports goggle on visual function to see whether visual impediment is a substantial factor in the resistance to use of protective eyewear.
Methods: We measured Snellen visual acuity, Ishihara colour vision and contrast sensitivity and performed Humphrey central 30 degrees and peripheral 30 degrees to 60 degrees threshold perimetry in eight volunteers (10 eyes) with and without a sports goggle and a hockey visor (half face shield). Subjects with normal acuity and normal confrontation fields who did not require presbyopic correction at near were enrolled. Five subjects (10 eyes) had further testing with threshold perimetry of the temporal crescent. The order in which the tests were performed (no mask first, visor first or goggle first) was alternated between subjects.
Results: There was no difference in Snellen acuity or Ishihara colour vision, and no statistically significant difference in contrast sensitivity or foveal threshold with or without protective eyewear. The visor caused a statistically significant decrease in the central 30 degrees mean deviation index compared to no mask (p = 0.001), but the goggle did not. Each of the peripheral quadrant threshold totals was significantly decreased with the visor compared with no mask (p < 0.05). The 30 degrees to 60 degrees temporal field was better preserved with the goggle than with the visor, but the nasal peripheral field was worse with the goggle than with the visor. Both the visor and the goggle caused a statistically significant decrease of more than 4 decibels in the temporal crescent threshold (p = 0.000).
Interpretation: Protective eyewear does not adversely affect Snellen acuity, contrast sensitivity, Ishihara colour vision or foveal threshold. The central 30 degrees field of vision is not affected by the sports goggle and is minimally depressed by the hockey visor. The goggle better preserves the temporal midperipheral field, but, unlike the visor, the goggle caused a monocular nasal lens rim scotoma. Both devices caused a depression of more than 4 dB of the far temporal field beyond 60 degrees (temporal crescent).