Abstract
Purpose: :
To describe the relationship between peripheral refraction and clinical characteristics of the eye in a two-year clinical study to evaluate the effectiveness of newly-developed progressive addition lenses on slowing myopia progression.
Methods: :
Seventy-seven Japanese children with myopia (age range: 6 to 12 years, mean refractive error:-2.88+/-0.93 D, refractive range: -1.00 to -4.50 D) were studied. Under cycloplegia, three measurements of refraction for the right eye at the corneal plane were taken at 0, 5, 15, 25, and 30 degrees in both the temporal and nasal visual fields, using an open-view infrared refractometer FR-5000 (Garndo Seiko). The relative peripheral refractive error (RPRE) was calculated to analyze the amount of change of the peripheral refractive power with respect to the foveal values. The relationships between RPRE and age, axial refractive error, axial length of the eye, and number of parental myopia were analyzed.
Results: :
The average (+/-SD) RPRE at 30 degree nasal (temporal retina) and temporal (nasal retina) visual fields was +1.10+/-0.71 D and +1.30+/-0.86 D, respectively. Boys had a longer mean axial length (P=0.016). Boys or children with myopic parents tend to show more hyperopic RPRE. Higher myopia and longer axial length were associated with more hyperopic RPRE after adjusting for age and parental myopia, but the correlations were weak (R2=0.02 and 0.03, respectively).
Conclusions: :
The children in this age range show a large intersubject difference in relative hyperopia in the peripheral retina regardless of degree of myopia or axial length. These results provide a baseline to evaluate longitudinal changes in peripheral refraction with myopia progression.
Keywords: myopia • clinical (human) or epidemiologic studies: risk factor assessment • development