Purpose:
In this study we will analyze in detail contact lens (CL) wearer demographics and its correlativity with population dynamics and economic conditions of Japan.
Methods:
Statistical evaluation was performed to history database of 183,093 patients, 112,920 women (61.6%) and 70,173 men (38.3%), whom purchased CLs from Okada Eye Clinic from January 2006 to December 2010. Trends in the purchasers were analyzed, and Spearman's rank correlation coefficient between CL purchase and Japan’s population and gross domestic product (GDP) were calculated.
Results:
Classified by modality, the most purchased lens was two-week frequent-replacement (51.2%), followed by daily-disposable (49.5%), rigid gas permeable (11.4%), conventional (10.4%), one-month replacement (1.1%), and one-week extended-wear CL (0.6%, duplicates included). Divided by type, the most purchased lens was spherical (88.8%), followed by toric (12.4%), cosmetic (circle 5.4% and color 2.8%), bifocal (1.2%), and other special CLs (0.3%, duplicates allowed). The average age of the patients was 31.2 ranging from 7 to 96 years old. The main age groups were 20’s (36.0%) and 30’s (28.4%), followed by 40’s (14.7%), 10’s (13.9%), 50’s (5.7%), 60’s (1.2%), under 10 (0.1%), and over 70 (0.1%). According to the national population census, Japan’s total population has been flat from 2006 (127.7 million) to 2010 (128.0 mill.), but the percentage of population over age 65 increased from 20.9% to 23.1%. The number of CL purchasers decreased in 10’s (-1.6%), 20’s (-5.2%), and 30’s (-0.1%), but increased in 40’s (+4.0%), 50’s (+1.8%) and 60’s (+1.1%) from 2006 to 2010. Focusing on the 20’s and 30’s, Japan’s population and the number of CL purchasers correlated significantly (r=0.976, p<0.01). Furthermore, a significant correlation between Japan’s GDP and the number of 20 to 39 years old CL purchasers was detected from 2006 to 2010 (r=0.709, p<0.05), but was not detected against the number of 40 to 69 year old CL purchasers (r=0.576, p>0.05).
Conclusions:
The number of CL purchasers in our clinic was positively correlated with Japan’s demographics and economic conditions. Though CLs are classified as specially controlled medical devices, they are distributed by retail sales, so changes in population dynamics and economic conditions influence their purchasing activities.