Distribution and progression of add power among people in need of near correction.

IMPORTANCE: This study helps to better understand the need and trend in presbyopic add power in the aging society.

BACKGROUND: Distribution and progression of presbyopic add power in East Asian population is largely unknown.

DESIGN: Prospective cohort study.

PARTICIPANTS: About 303 participants from a population-based study of residents aged 35 years and older in Guangzhou, China.

METHODS: Visual acuity (VA) test and non-cycloplegic automated refraction were performed at baseline in 2008 and the 6-year follow-up per standardized protocol. Participants with presenting near VA ≤ 20/40 underwent distance subjective refraction and add power measurement by increasing plus lens at a standard distance of 40 cm at each visit.

MAIN OUTCOME MEASURES: Add power at baseline and follow-ups.

RESULTS: Mean (standard deviation) age of the study participants was 57.6 (11.1) years and 50.2% were female. The mean add power at baseline was 1.43, 1.73, 2.03 and 2.20 diopters (D) for individuals in the age groups of 35-44, 45-54, 55-64 and 65+ years, respectively. Participants with older age and lower educational level had significantly higher add power requirements (P < 0.001). The overall 6-year increase in add power was 0.15D (95% CI: 0.06 to 0.25), and was smaller in myopic subjects (P = 0.03). Baseline age and add power, but not changes in biometric factors, were associated with longitudinal change in add power (P < 0.001).

CONCLUSIONS AND RELEVANCE: Distribution and progression of add power in Chinese was different from that previously suggested by Caucasian studies. More studies are needed to establish up-to-date age-related add power prescription norms for population of different ethnicities.