Older Patients with AMD, Glaucoma Exhibit Standard Equilibrium Function

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As falls in older adults are a significant public health concern, a new observational study sought to assess the equilibrium function and susceptibility to falls among those with age-related macular degeneration (AMD) and glaucoma.¹

Most patients attending an ophthalmology outpatient clinic in Japan demonstrated normal postural control and a lower fall risk than patients with vestibular disorders, suggesting visual impairment did not significantly impact postural stability in this population.

“Nonetheless, medical practitioners and policymakers should consider vestibular function evaluations in visually impaired patients with a heightened fall risk due to other underlying conditions,” wrote the investigative team, led by Takahiro Tokunaga, department of otorhinolaryngology, Shinseikai Toyama Hospital.

Research from the Centers for Disease Control and Prevention (CDC) found more than one-quarter of adults aged ≥65 in the United States experienced ≥1 fall in the preceding year, with many experiencing injuries.² A variety of factors influence fall risk, but visual deficits, prevalent in the older population, have been identified as potential risk factors for falls.

The combination of visual, vestibular, and somatosensory inputs is crucial for postural regular, with deficits linked to an elevated fall risk.³ Although visual deficits are one of many causes of falls, Tokunaga and colleagues noted limitations in research on the correlation between visual deficits and falls impedes the introduction of specialized fall prevention strategies for those with visual impairments.¹

In the current study, the team evaluated the equilibrium function, fall risk, and fall-related self-efficacy, a measure of an individual’s belief in their capacity to reach specific goals, among individuals with AMD and glaucoma attending a standard ophthalmology outpatient clinic, without subjective vertigo symptoms.

Conducted between April 2021 and March 2022, the study cohort consisted of 30 patients with AMD (median age, 76 years) and 30 patients with glaucoma (median age, 64.5 years). Visual acuity and visual fields were measured by investigators, with outcome measures centering around the equilibrium function and fall risk evaluations.

Evaluation of equilibrium function included pathological eye movement analysis, bedside head impulse test (HIT), single-leg upright test, eye-tracking test (ETT), optokinetic nystagmus (OKN), and posturography. Questionnaires were provided for fall risk determinants, including the Dizziness Handicap Inventory (DHI), Activities-Specific Balance Confidence (ABC) scale, Falls Efficacy Scale-International (FES-I), and Hospital Anxiety and Depression Scale (HADS).

In the previous six months, data showed that 7% of patients with AMD and glaucoma reported falls. Most participants demonstrated standard outcomes in equilibrium function evaluations, including the FES-I scores (AMD: 23.0; glaucoma: 23.5) and the median ABC scale scores (AMD: 95.3; glaucoma: 96.3; P = .76).

Fall-related self-efficacy scores showed that 3.3% of patients with AMD and 10.0% of patients with glaucoma registered an ABC scale score of <67%, a threshold indicative of an increased fall risk in older individuals.

Moreover, most participants across both cohorts showed normal HIT, ETT, and OKN findings. Investigators found that 80% of patients with AMD and 73% with glaucoma had standard ETT results, while all patients with AMD and 90–97% of those with glaucoma demonstrated normal OKN results. Positive HIT results were identified in 10–13% of patients with AMD and 3% of those with glaucoma.

Tokunaga and colleagues used the visual/somatosensory ratio as an indicator of visual dependence of postural control, finding the ratio decreased in patients with impaired visual fields. Specifically, greater peripheral visual field impairment was associated with a tendency for sensory reweighting from visual to somatosensory.

“This indicates potential sensory reweighting in patients with compromised visual fields, suggesting that other senses might compensate for the deteriorated visual fields,” they wrote.

References

1. _{Tokunaga T, Takegawa R, Ueta Y, Manabe Y, Fushiki H. Assessing fall risk and equilibrium function in patients with age-related macular degeneration and glaucoma: An observational study. PLoS One. 2024;19(4):e0301377. Published 2024 Apr 1. doi:10.1371/journal.pone.0301377}
2. _{Moreland B, Kakara R, Henry A. Trends in Nonfatal Falls and Fall-Related Injuries Among Adults Aged ≥65 Years - United States, 2012-2018. MMWR Morb Mortal Wkly Rep. 2020;69(27):875-881. Published 2020 Jul 10. doi:10.15585/mmwr.mm6927a5}
3. _{Dominguez L. Postural control and perturbation response in aging populations: fall risk implications. J Neurophysiol. 2020;124(5):1309-1311. doi:10.1152/jn.00767.2019}