THREE-YEAR CHANGES IN REFRACTION AND ITS COMPONENTS IN YOUTH-ONSET AND EARLY ADULT-ONSET MYOPIA

Title THREE-YEAR CHANGES IN REFRACTION AND ITS COMPONENTS IN YOUTH-ONSET AND EARLY ADULT-ONSET MYOPIA
Author, Co-Author Theodore Grosvenor, Rolene Scott
Topic
Year
1992
Day
Monday
Program Number
2:15 pm
Room
Scotland B
Affiliation
Abstract The purpose of our study was to compare the refractive components, and their changes with the passage of time, for 79 young adults of whom 29 were youth-onset myopes, 26 were early adult-onset myopes, and 24 were emmetropes. In the initial evaluation it was found that mean corneal refracting power, mean vitreous chamber depth and mean axial length were significantly greater for both the youth-onset and early adult-onset myopes than for the emmetropes; and that the differences in the refractive components for the two groups of myopes were related to the fact that the youth-onset myopes were more myopic than the early adult-onset myopes. During the 3-year period, mean spherical equivalent refraction for subjects in all 3 refractive error groups changed in the direction of increasing myopia. For each of the 3 groups, the only refractive component changes having significant correlations with changes in refraction during the 3-year period were vitreous chamber depth and axial length. We interpret these results as indicating that: (a) whether axial elongation presents itself before, during, or after the completion of the normal growth period, the result is an eye whose cornea is significantly steeper and whose vitreous chamber is significantly deeper as compared to an emmetropic eye of a person of the same age; (b) when myopia progresses with the passage of time, the progression is due to an increase in vitreous chamber depth that is not fully compensated by a decrease in lens power. We find no evidence for the existence of lenticular myopia. We conclude, therefore, that all myopia is axial in origin.
Affiliation of Co-Authors
Outline