Impact of Glasses for Vision Problems on Cognitive Function in Rural Older Adults

The Impact of Spectacle Intervention for Refractive Error and Presbyopia on Cognitive Function in Rural Older Adults

The aim of this project is to explore whether vision correction can effectively slow cognitive decline in older adults.

The primary question it seeks to answer is: Can providing free near and/or distance vision correction glasses to older adults with refractive errors or uncorrected vision, who have normal baseline cognition and hearing, reduce the rate of cognitive decline over 36 months in a cost-effective manner? Researchers will compare the rate of cognitive decline over 36 months between older adults who receive refractive correction and those who do not.

Exploratory subgroup analyses will be conducted to assess whether the intervention effect on cognitive decline differs according to baseline vision correction needs (near vision correction, distance vision correction, or both) and baseline cognitive function. These analyses will be interpreted cautiously due to their exploratory nature.

Inclusion Criteria:

• Older adults who meet all of the following criteria will be eligible to participate in this study:

  • Registered as a rural resident (holding rural household registration);
  • Age from 60 to 79 years at the time of enumeration;
  • Resident in the household for > = 3 months and planning to reside in the local area for the trial duration;
  • Distance vision impairment (VI, presenting visual acuity [VA] < 6/12 in the better-seeing eye and improving to ≥ 6/7.5 or better in either eye with spectacle correction) and/or near VI (presenting near VA < 6/12 at 40 cm when measured binocularly and improving to ≥ 6/7.5 or better in either eye with near correction);
  • Independent mobility with or without the support of a walking stick;
  • Chinese version of the Mini-Mental State Examination (C-MMSE) score above the following cut-offs (out of 30): >17 for illiterate participants, >20 for those with primary school education, >22 for those with junior high school education, and >23 for those with high school education or above.
  • Willingness to participate, to be randomized to either study group, and to adhere to the protocol

Exclusion Criteria:

• Presence of glaucoma or visually significant cataract, or a history of surgical treatment for these or other major ocular conditions;
• Consistent use of prescription spectacles and/or hearing aids;
• Serious medical illness likely to result in loss to follow-up. Those less severely affected by conditions such as hypertension and/or diabetes will be eligible;
• Failure on the whispered voice hearing screening test in the better ear (unable to repeat > = 3 out of 6 words whispered from behind the participant at a distance of 50 cm);