Diversity of Peripheral Refraction Patterns-Have These Been Oversimplified?

Purpose: To describe patterns of peripheral refraction based on spherical equivalent refraction and on tangential and sagittal refractions, and to assess the association of peripheral refraction patterns with different central refractions. Methods: Peripheral refraction data from 737 individuals (14.7 ± 5.1 years old) were analyzed. Peripheral refraction was determined along the horizontal field at ±30° eccentricity using an open-field autorefractor in 89 hyperopes, 276 emmetropes, and 372 myopes. Values were converted into spherical equivalent refraction and into tangential and sagittal refractions. Nine different peripheral refraction patterns (A-I) were described based on spherical equivalent refraction, and 81 patterns were described based on tangential and sagittal refractions. Results: Using spherical equivalent refraction, all nine possible peripheral refraction patterns (A-I) were represented. Type I (relative peripheral myopia in nasal and temporal retinas) was seen in 40% of hyperopes, in 32% of emmetropes, and in 8% of myopes. Type A (relative peripheral hyperopia in nasal and temporal retinas) was seen in 20% of myopes and in ≤1% of hyperopes and emmetropes. No pattern was unique to any refractive group. Using tangential and sagittal refractions, 47 out of 81 possible patterns were represented. The three refractive groups shared 19 patterns in common. Hyperopes, emmetropes, and myopes had two, six, and eleven unique patterns, respectively. Conclusions: Many types of peripheral refraction patterns were observed, and these may provide insights into the complexities of eye growth and myopiogenesis. Tangential and sagittal refractions should be considered to understand peripheral refraction rather than spherical equivalent refraction alone.