Age-related decline in visual acuity, contrast sensitivity, dark adaptation, stereopsis, and visual field that affects ADL, QOL, and fall risk is called “age-related visual function decline.” This visual decline is not merely “difficulty seeing” but is a major contributor to the deterioration of physical, mental, and social health in older adults (frailty).
Frailty refers to a state of vulnerability in older adults. In the phenotypic model proposed by Fried et al. (Fried criteria), meeting three or more of the following five items defines frailty, and one to two items defines prefrailty 1).
Older adults with visual impairment are reported to have a 2 to 3 times higher risk of frailty compared to healthy individuals2). Decreased visual function is not just a local problem of “difficulty seeing” but becomes an entry point to frailty by triggering a chain of falls, avoidance of going out, social isolation, and cognitive decline.
The prevalence of visual impairment increases sharply after age 75. Visual impairment is established as an independent risk factor for falls3), and RCT data show that first-eye cataract surgery reduces fall risk by 34%3).
Presbyopia (loss of accommodation) begins around age 40 due to hardening of the lens, and progression is inevitable. However, visual function can be compensated with reading glasses, progressive lenses, or multifocal contact lenses. Vision loss due to cataracts can also be significantly improved by phacoemulsification and intraocular lens implantation, which is also expected to reduce fall risk. In many cases, the problem is not the decline in visual function itself but the lack of appropriate correction or treatment.
Age-related visual function changes are classified into seven main categories.
Presbyopia (loss of accommodation)
Difficulty reading close-up text: The lens loses elasticity, making it hard to focus on near objects.
Holding smartphones farther away: Increased tendency to extend arms to see clearly at close range.
Slower reading speed: Eye strain easily occurs during prolonged near work.
Decreased contrast sensitivity and glare
Difficulty noticing steps and obstacles: Difficulty identifying objects in low-contrast environments.
Poor vision at night or on cloudy days: Scattered light and reduced sensitivity combine to decrease visual clarity.
Oncoming headlights are dazzling: Increased glare due to scattered light from cataracts.
Delayed dark adaptation and color vision changes
Difficulty walking in dark places: Slower regeneration of rhodopsin in rod cells, leading to delayed dark adaptation.
Changes in color perception: Yellowing of the lens reduces sensitivity to short wavelengths (blue), making it difficult to distinguish white and blue colors.
Visual field narrowing and reduced stereopsis
Overlooking peripheral obstacles: Visual field narrowing due to conditions like glaucoma reduces peripheral vision.
Difficulty judging distances: Reduced binocular vision accuracy leads to poorer stereopsis, making it hard to judge step height.
Tripping on stairs: Combined effects of reduced stereopsis and contrast sensitivity increase fall risk.
Visual impairment alone does not directly cause frailty, but it can lead to physical and social frailty through the following chain.
Two visual functions are important for preventing falls: recognizing steps and maintaining balance. When contrast sensitivity declines, low-contrast steps become harder to see; visual field loss leads to overlooking peripheral obstacles; and reduced stereopsis impairs judgment of step depth and height. The combination of these three visual impairments significantly increases fall risk.
Age-related visual decline involves a combination of local ocular structural changes and systemic age-related changes in neural function.
Assessment of visual impairment and frailty is performed by combining ophthalmological and systemic evaluations.
| Assessment Item | Main Examination Method | Purpose |
|---|---|---|
| Visual acuity (distance, intermediate, near) | Visual acuity chart | Basic assessment of presbyopia, cataract, and AMD |
| Contrast sensitivity | Pelli-Robson chart, etc.11) | Assessment of functional vision not captured by visual acuity charts |
| Visual field | Humphrey/Goldmann perimetry | Screening for glaucoma and neurological diseases |
| Glare | Glare tester | Assessment of scattered light due to cataract |
| Dark adaptation | Dark adaptometer (e.g., AdaptDx) | Assessment of rod function and early AMD |
| Stereopsis | Landolt C stereopsis test | Assessment of binocular vision |
| Vision-related quality of life | VFQ-2513) | Quantification of impact on daily functioning |
The Pelli-Robson chart measures contrast sensitivity by varying the contrast of letters in steps, and can detect decreased contrast sensitivity even when visual acuity is within the normal range11).
The VFQ-25 (25-Item National Eye Institute Visual Function Questionnaire) is a 25-item questionnaire that assesses the impact of visual function on daily life, and is widely used as a patient-reported outcome measure for a broad range of eye diseases including cataract, glaucoma, and AMD13).
The Ministry of Health, Labour and Welfare’s Basic Checklist is a screening tool for preventing the need for long-term care, consisting of 25 items related to exercise, nutrition, oral health, going out, forgetfulness, and depression12). Combining it with ophthalmic visual function assessment makes it easier to detect declines in daily functioning associated with visual impairment.
It is recommended to combine screening by a primary care physician using the Ministry of Health, Labour and Welfare’s Basic Checklist with ophthalmic visual function assessment (visual acuity, contrast sensitivity, visual field testing). If 8 or more items on the Basic Checklist are positive, the risk of needing long-term care is considered high. When visual impairment is identified, interventions to improve visual function such as cataract surgery, refractive correction, and low vision care are the first steps in preventing falls and frailty.
| Disease/Problem | Treatment/Intervention | Frailty Prevention Effect |
|---|---|---|
| Presbyopia | Reading glasses, progressive lenses, multifocal contact lenses | Maintaining QOL through reading and information acquisition |
| Cataract | Phacoemulsification + intraocular lens (IOL) implantation | 34% reduction in fall risk for the first eye3) |
| Glaucoma | Intraocular pressure reduction (eyedrops, laser, surgery)9) | Reduced fall risk due to visual field preservation |
| Age-related macular degeneration (wet type) | Anti-VEGF intravitreal injection (ranibizumab, aflibercept, etc.) | Maintenance and recovery of central vision |
| Dry eye | Artificial tears, hyaluronic acid eyedrops, diquafosol sodium 3% eyedrops 6 times daily | Stabilization of visual function |
| Low vision | Local consultation services and support facilities14) | Coordination for independent living |
Active exercise prescription after vision correction is effective for frailty prevention. Walking and balance training (e.g., tai chi, yoga) have been reported to reduce fall risk 3). Improving visual function increases the frequency of going out, and promoting social participation helps prevent sarcopenia (muscle loss) and cognitive decline 5).
Yes, it does. In a randomized controlled trial (RCT) by Harwood et al., older women who underwent first-eye cataract surgery had a 34% reduction in fall risk 3). In a second-eye surgery RCT by Foss et al., visual function and health status improved, but the 32% reduction in fall rate was not statistically significant, and the effect was considered uncertain 4).
With aging, the lens undergoes nuclear sclerosis, yellowing, and loss of elasticity 8). Nuclear sclerosis results from oxidation and cross-linking of crystallin proteins, leading to increased light scattering (glare and reduced contrast) and loss of accommodative power (presbyopia). Yellowing increases absorption of short-wavelength light, manifesting as reduced blue color perception.
Age-related decline in meibomian gland function (MGD) and atrophy of lacrimal glands reduce the quality and quantity of tears 7). This destabilizes the tear film, causing fluctuations in visual function. Dry eye has a high prevalence among older adults and is a major cause of visual variability.
The density of rod cells (photoreceptors for night and scotopic vision) decreases with age, and the regeneration rate of rhodopsin (visual pigment) slows. This prolongs dark adaptation (adjustment from bright to dark environments), making nighttime walking difficult. Cone cells (photoreceptors for daytime and color vision) are also affected by aging, leading to reduced high-frequency contrast sensitivity.
Visual processing speed from the retina to the visual cortex (occipital lobe) declines with age 15). The time required for the brain to process signals from the eyes (visual reaction time) increases, making it difficult to respond quickly to moving objects. This is also associated with fall risk.
The vicious cycle of frailty is formed as “malnutrition → muscle weakness → reduced activity → further malnutrition” 1). Visual impairment intervenes in this cycle through multiple pathways. Reduced physical activity due to avoidance of going out leads to sarcopenia (loss of skeletal muscle mass and strength), increasing the risk of falls, fractures, and subsequent bedridden state. Visual impairment is also a strong predictor of social frailty 2).
