Prismatic displacement effect of progressive multifocal glasses on reaction time and accuracy in elderly people

Multifocal Spectacle and Monovision Treatment of Presbyopia and Falls in the Elderly

Presbyopia is an age-related condition that affects approximately 1.8 billion people worldwide. Strategies to correct presbyopia include both nonsurgical and surgical approaches. Although eye care providers assume that multifocal spectacles and monovision have lower risks than surgical interventions, there is evidence to suggest that the use of these nonsurgical approaches in the older population increases the risk for trips and falls. Each year, fall-related injuries and deaths are reported in a substantial portion of the population, both globally and in the United States. Previous studies have shown a link between visual acuity, contrast sensitivity, stereoacuity, and visual field impairments and falls. More recent mechanistic and epidemiological studies have shown that multifocal spectacles and monovision can increase the risk for falls as well. Although evidence on the financial burden of falls related to multifocal spectacles or monovision is limited, total direct medical costs related to falls associated with multifocal spectacles are estimated to be approximately $11 billion annually in the United States. Therefore, it is important that eye care providers consider the risk for falls associated with multifocal spectacles and monovision when making decisions on the best strategy for correcting presbyopia in older adults. [J Refract Surg. 2021;37(6 Suppl):S12-S16.].

Intermediate addition multifocals provide safe stair ambulation with adequate 'short-term' reading

Purpose

A recent randomised controlled trial indicated that providing long‐term multifocal wearers with a pair of distance single‐vision spectacles for use outside the home reduced falls risk in active older people. However, it also found that participants disliked continually switching between using two pairs of glasses and adherence to the intervention was poor. In this study we determined whether intermediate addition multifocals (which could be worn most of the time inside and outside the home and thus avoid continual switching) could provide similar gait safety on stairs to distance single vision spectacles whilst also providing adequate ‘short‐term’ reading and near vision.

Methods

Fourteen healthy long‐term multifocal wearers completed stair ascent and descent trials over a 3‐step staircase wearing intermediate and full addition bifocals and progression‐addition lenses (PALs) and single‐vision distance spectacles. Gait safety/caution was assessed using foot clearance measurements (toe on ascent, heel on descent) over the step edges and ascent and descent duration. Binocular near visual acuity, critical print size and reading speed were measured using Bailey‐Lovie near charts and MNRead charts at 40 cm.

Results

Gait safety/caution measures were worse with full addition bifocals and PALs compared to intermediate bifocals and PALs. The intermediate PALs provided similar gait ascent/descent measures to those with distance single‐vision spectacles. The intermediate addition PALs also provided good reading ability: Near word acuity and MNRead critical print size were better with the intermediate addition PALs than with the single‐vision lenses (p < 0.0001), with a mean near visual acuity of 0.24 ± 0.13 logMAR (~N5.5) which is satisfactory for most near vision tasks when performed for a short period of time.

Conclusions

The better ability to ‘spot read’ with the intermediate addition PALs compared to single‐vision spectacles suggests that elderly individuals might better comply with the use of intermediate addition PALs outside the home. A lack of difference in gait parameters for the intermediate addition PALs compared to distance single‐vision spectacles suggests they could be usefully used to help prevent falls in older well‐adapted full addition PAL wearers. A randomised controlled trial to investigate the usefulness of intermediate multifocals in preventing falls seems warranted.