Purpose: to examine the effect of correction type on myopia progression in subjects who completed a randomized clinical trial of bifocal glasses.
Methods: Forty nine of 55 subjects, who completed a 42-month clinical trial, returned for a 1-yr post-treatment visit (54 months of follow-up). Original treatment assignments were single-vision glasses (SV) or bifocal glasses (BF) with a +1.50 D add. Once released from treatment, children chose either to wear soft contact lenses (CL), to continue in their assigned glasses, or to switch to the other type of glasses. Progression during that year, i.e. from 42 to 54 mos., was used to estimate the effect of switching correction type. Myopia was measured with automated refraction 30 min after instilling two drops of 1% tropicamide. We used ANOVA with age as co-variate and averaged myopia over both eyes. Means presented here are age-adjusted.
Results: In the SV group, seven children who switched to CL progressed 1.8 x faster than the twelve children who remained in BF (p=0.005), those remaining in SV progressing an average of 0.27 D compared to 0.75 D for those switching to CL. In the BF group, twelve children who switched to CL progressed 1.9 x faster than the twelve who remained in SV (p=0.001), those remaining in BF progressing an average of 0.26 D compared to 0.75 D for those switching to CL. Three children from the original SV group who switched to BF on average decreased in myopia by 0.08 D compared to an increase of 0.27 D for the twelve remaining in SV (p=0.02).
Conclusion: In the children we studied, wearing soft-contact lenses seemed to increase myopia progression compared to wearing either single-vision or bifocal glasses.
Keywords: 357 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • 481 myopia • 367 contact lens
GW Fulk1, LA Cyert2 and DE Parker3
1 College of Optometry Northeastern State University Tahlequah OK
2 Tahlequah OK
3 Biostatistics and Epidemiology Univ of Oklahoma Health Science Center Oklahoma City OK
Commercial Relationships: G.W. Fulk, None; L.A. Cyert, None; D.E. Parker, None.
Grant Identification: NIH EY10613