title: Sunglasses with thick temples and frame constrict temporal visual field.
abstract: OBJECTIVE
  Our aim was to compare the impact of two types of sunglasses on visual field and glare: one ("thick sunglasses") with a thick plastic frame and wide temples and one ("thin sunglasses") with a thin metal frame and thin temples.
  
  
  METHODS
  Using the Goldmann perimeter, visual field surface areas (cm²) were calculated as projections on a 30-cm virtual cupola. A V4 test object was used, from seen to unseen, in 15 healthy volunteers in the primary position of gaze ("base visual field"), then allowing eye motion ("eye motion visual field") without glasses, then with "thin sunglasses," followed by "thick sunglasses." Visual field surface area differences greater than the 14% reproducibility error of the method and having a p < 0.05 were considered significant. A glare test was done using a surgical lighting system pointed at the eye(s) at different incidence angles.
  
  
  RESULTS
  No significant "base visual field" or "eye motion visual field" surface area variations were noted when comparing tests done without glasses and with the "thin sunglasses." In contrast, a 22% "eye motion visual field" surface area decrease (p < 0.001) was noted when comparing tests done without glasses and with "thick sunglasses." This decrease was most severe in the temporal quadrant (-33%; p < 0.001). All subjects reported less lateral glare with the "thick sunglasses" than with the "thin sunglasses" (p < 0.001).
  
  
  CONCLUSIONS
  The better protection from lateral glare offered by "thick sunglasses" is offset by the much poorer ability to use lateral space exploration; this results in a loss of most, if not all, of the additional visual field gained through eye motion.
authors.affiliation: *MD †MSc ‡MD, PhD Departments of Ophthalmology (ED, SC-P, FM) and Biostatistics and Clinical Research (AED, SA), CHU de Caen; and Université de Caen Basse-Normandie (AED, FM), Medical School, Caen, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Denion
authors.forename: Audrey Emmanuelle
authors.initials: AE
authors.lastname: Dugué
authors.forename: Sylvain
authors.initials: S
authors.lastname: Augy
authors.forename: Sophie
authors.initials: S
authors.lastname: Coffin-Pichonnet
authors.forename: Frédéric
authors.initials: F
authors.lastname: Mouriaux
mesh_terms: D000328:Adult; D005135:Eye Protective Devices; D005260:Female; D019466:Glare; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*