Abstract
Purpose :
We undertook a 5-year large-scale epidemiologic study of approximately 460,000 eyes of Japanese patients, who had been prescribed soft contact lenses (SCL), with or without UV protection to correct ametropia. The purpose of this research was to clarify any effect ultraviolet exposure may have on the progression of myopia.
Methods :
The subject of this study was the eyes of patients, in the 10 to 29 year age range, who were prescribed SCL at Okada Eye Clinic in Kanagawa, Japan, between 2002 and 2011, who were tracked over a 5-year period (between 2007 to 2016). From a total of 2,143,154 eyes, 1,211,608 were prescribed UV protected SCLs (UV+SCL); and 931,546 eyes were prescribed SCLs without UV protection (UV-SCL). The total number of eyes which were able to be tracked for 5 years was 458,597 (UV+SCL: 290,775 eyes; and UV-SCL: 167,822 eyes).
Results :
First, analysis was conducted of the change in the degree of refraction over the 5 years. For men in UV+SCL this change was -0.471D; and in UV-SCL, -0.472D. The difference was slight but the progress of myopia in UV-SCL was significantly larger than in UV+SCL (P<0.001). For women in UV+SCL, this change was -0.440D; and in UV-SCL, -0.463D. As with men, the progress of myopia in UV-SCL was significantly greater than UV+SCL (P=0.023)
Further, the power of the SCL prescribed the first time the patient came to Okada Eye Clinic was checked and divided into 3 groups of myopia (high myopia (S < -6.00D); medium myopia （-6.00D < S < -3.00D); low myopia (-3.00D < S < -0.25D)）. Again the change in the degree of refraction over 5 years was analyzed.
For patients with high myopia: in UV+SCL the change was -0.299D; in UV-SCL, -0.324D. For those with medium myopia: in UV+SCL the change was -0.427D; in UV-SCL, -0.439D. For patients with low myopia: in UV+SCL the change was -0.525D; in UV-SCL, -0.546D. For all degrees of myopia, myopia progression was significantly more rapid in UV-SCL compared to UV+SCL. (P=0.025, 0.012, 0.023).
Conclusions :
Through analysis of changes in the degree of refraction over 5 years by gender and myopic degree, it can be determined that in each instance, myopia progression of UV-SCL was significantly more rapid than UV+SCL. From this result, it is suggested that ultraviolet exposure may be a risk factor in myopia progression.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.