Effect of a near-vision task on the response AC/A of a myopic population.
The effect of a 14 minute near-vision task on the response accommodative convergence/accommodation (AC/A) ratio was investigated for three refractive groups (each comprising N = 17)--emmetropes, early-onset myopes (EOM), i.e. myopia onset prior to 15 years of age, and late-onset myopes (LOM), i.e. onset 15 years or later. AC/A ratios were derived from accommodative stimuli of 3.0, 3.9 and 4.6 D. Accommodation was measured using an objective infra-red autorefractor which allowed unrestricted viewing through a semi-silvered mirror and this permitted concomitant vergence changes to be assessed using a Maddox rod and tangent scale. EOMs exhibit a significantly higher response AC/A ratio than the two other refractive groups. The implications of these modifications in response AC/A are discussed with reference to current models of accommodation-vergence interaction.
Rosenfield
M
M
Department of Vision Sciences, Aston University, Birmingham, U.K.
Gilmartin
B
B
D000065:Accommodation, Ocular; D000328:Adult; D003290:Convergence, Ocular; D005133:Eye Movements; D006801:Humans; D009216:Myopia / Q000503:physiopathology*; D012029:Refraction, Ocular; D013997:Time Factors; D014785:Vision, Ocular / Q000502:physiology