Abstract
Purpose: :
To determine the impact of uncorrected presbyopia on the ability to perform locally relevant tasks of daily living, and on vision-related quality of life (QoL), in rural Nepal.
Methods: :
A prospective unmatched case-control study recruited 71 consecutive presbyopic patients aged >40years, and 103 chaperones, presenting to a free primary eye care clinic in Sarlahi, Nepal. After near and distance vision testing and refraction, self-reported QoL was assessed using an instrument validated in Southern India. An instrument to assess near vision-related difficulty with 15 tasks was piloted, administered, and validated using Rasch analysis.
Results: :
The mean age of cases was 53.4 years (sd 9.9y), 35 (49%) were male, and 46 (64.8%) were illiterate, whilst the mean age of controls was 28.8 years (sd 7.4y), 72 (70%) were male, and 27(26%) were illiterate. The presenting near visual acuity was N10 or N12 in 37(52.1%) cases, N14 or N18 in 31(43.7%), and N24 or N36 in 3(4.2%), and 18 cases (25%) had additional uncorrected refractive error for distance at presentation. In comparison to one control (1%), 16 (22.5%) presbyopes had modestly reduced vision-associated QoL (p<0.001), mainly affecting social and psychological domains. 71(100%) cases, versus 10 (9.7%) controls, reported difficulty with at least one task of daily living (p<0.0001) and, on average, cases reported difficulty with 64% of tasks previously performed. The 5 tasks most affected by near vision impairment were threading a needle, removing lice from children’s heads, removing thorns from skin, writing letters and reading. This instrument demonstrated good fit to the Rasch model; the mean(SD) person and item fit residual values were -0.1(1.2) and 0.1(0.9) respectively; there was good targeting of person ability and item difficulty; good person separation reliability (0.87); and no evidence of differential item functioning or disordered thresholds.
Conclusions: :
The Rasch-validated tasks of daily living instrument enabled valuable assessment of the functional impact of near vision impairment in this low literacy population. This study reveals that uncorrected presbyopia has a modest impact on vision-related quality of life and a considerable impact on the daily lives of individuals living in rural Nepal.
Keywords: presbyopia • quality of life • aging: visual performance