Normal changes in the eye and visual system with aging lead to deterioration of functional vision in later life.
Impacts of age on Visual Functions:
Visual Acuity (VA)/ Cognitive Decline
Visual Contrast Sensitivity
Dark and Light Adaptation
Glare Recovery
Colour discrimination
Stereopsis
Speed of Visual Processing/Motion Perception
Visual Field
Eye movements
Visual Acuity (VA) and Age
As we age, our vision may not be as sharp.
Visual Acuity (VA) Assessment:
Measures the ability to recognize small details with precision.
VA depends on optical and neural factors:
Optical factors- affects the image
Neural factors:
Health and functioning of the retina
Neural pathways to the brain
Cognitive processing
Example case: Sarah (60-year-old)
Sarah's distance visual acuity:
With prescription:
RE: 0.10 Log MAR
LE: 0.00 Log MAR
Prescription:
RE: SPH -0.25, CYL
LE: SPH -0.25
Use: Driving
PD: 65/63mm
Why the normal decline in VA happens:
Changes in the lens:
Lens becomes less flexible and less transparent with age.
Makes it harder for the eye to focus on close-up objects, leading to presbyopia.
Accommodative power decreases commonly around the age of 40-50.
Research Studies on Visual Acuity (VA) and Age
The Framingham Eye Study (Massachusetts, USA, 1973):
Over 3,000 adults aged 28-84 years
VA declined with age, with the greatest decline occurring after the age of 60.
The Eye and Aging by R. Weale (1978) Review article
The lens becomes less transparent and less flexible with age, leading to a decrease in VA and risk of cataracts.
The retina changes with age, including a decrease in the number of photoreceptor cells and changes in the structure of the retinal pigment epithelium, which can lead to age-related macular degeneration.
Changes in the eye's refractive properties with age can lead to difficulty with near vision (presbyopia) and a decreased ability to focus on distant objects.
The Salisbury Eye Evaluation Project (Salisbury, Maryland –USA 1993-1995)
2500 participants, age: 65- 84
VA declined with age
Half participants had VA worse than 20/40 in at least one eye
The Blue Mountains Eye Study (Blue Mountains area-Australia- NSW 1992 and 1994)
Over 3,500 participants aged 49 years and older
VA declined with age
Prevalence of visual impairment 3% in aged 49-54 years to 36% in those aged 85 years or older.
Uncorrected refractive error was a major cause of visual impairment, particularly in older adults.
Identified other risk factors for visual impairment, such as smoking, hypertension, and diabetes
Sarah’s case according to the evidence
VA for distance could be affected, due to lens changes (Weale, 1978). However, Sarah’s distance VA is OK.
VA declines with age / with the greatest decline at 60 (Framingham Study, 1973; Weale,1978; The Salisbury eye project,1995; Blue Mountains eye study,1994 ). Sarah is 60 years old, so we expect any change in VA, maybe in near vision.
Changes in the eye’s refractive properties with age (Weale,1978). Sarah could have presbyopia, an uncorrected refractive error causing visual impairment
Lens changes/ less flexible and transparent (Weale,1978). How is her lens in terms of flexibility, considering that evidence has shown this aspect to be important?
Accommodative Power
Infants possess high accommodative power
Gradually power declines through childhood and adolescence.
Stable during early adulthood.
Around the age of 40 decreases in accommodative power (Bruckner et al 1987)*
Uncorrected near acuity declines abruptly between the ages of 45 and 50 and continues to decline thereafter at a slower rate ( Duane, 1912)*
Duane's curve of accommodation loss versus age
Sarah’s near vision analysis
Sarah’s near-distance visual acuity:
Jaeger chart- using Snellen notation:
RE: J5 (approx. 20/40)
LE: J5 (approx. 20/40)
Sarah’s Accommodative Amplitude:
RE: 1.25 D
LE: 1.25 D
Her near point would be 80cm; this may be the reason she feels uncomfortable when she is reading small- size printing.
Declining amplitude of accommodation according to Donders*
Changes in the Pupil
Aging leads to decreased pupil dilation, affecting vision in low-light situations.
Contributing factors:
Relative dilator atrophy compared to the sphincter muscles.
Increased iris rigidity.
Reduced sympathetic drive.
Decline in parasympathetic inhibition.
Chronic fatigue exacerbates these changes.
Sarah’s pupil changes
Sarah’s pupil reaction:
Under ambient light conditions:
RE: 5mm
LE: 5mm
Under light* conditions (Direct pupillary light reflex (PLD) test):
RE: 3mm
LE: 3mm
Recovery dark room(dilation) 1 minute * Standard light (direct ophthalmoscope light)
Sarah's symptoms related to driving could be attributed to changes in pupil size, light stimulation on the retina, and reduction in photoreceptor cells as we age.
Sarah’s case answers, plain language
Keep doing what you're doing with your healthy lifestyle, especially spending time outdoors. It's good for your eyes. When you're outside, make sure to wear sunglasses. They protect your eyes from the sun's bright light and harmful UV rays. Now, about those struggles with reading small print? It's likely due to something called presbyopia. As we get older, the lens inside our eyes becomes less flexible, making it harder to focus on close-up things like books or screens. But don't worry, wearing the right prescription glasses can help with that. And if you're having trouble seeing things far away too, that's also normal as we age. It happens because the eyesight might decrease a bit, and the pupil (the black part in the center of your eye) may not adjust as quickly to changes in light. This can be linked to having fewer photoreceptor cells in the back of your eye, which are the cells that help you see. But again, the right glasses can help improve your vision and make things clearer.
Association between Visual Acuity and Cognitive Decline
VA and cognitive decline Research Findings:
Some studies* have demonstrated a correlation between visual acuity and cognitive function in older adults.
Individuals with poorer visual acuity tend to perform worse on cognitive tests evaluating memory, attention, processing speed, and executive function.
Impact on Daily Activities:
Visual impairment significantly affects daily activities such as reading, driving, navigation, and facial recognition.
Difficulties in these tasks may lead to increased dependence, social isolation, and reduced quality of life.
VA and cognitive decline
VA may be used in combination with other screening measures to determine risk for cognitive decline
Suggest the use of more reliable screening methods for VA (i.e., log MAR) charts.
It has been documented that there is a relationship between visual acuity problems and hearing loss*.
Case of Marja (65 years old)
She is a retired librarian, who struggles with poor vision and cognitive decline. Despite wearing glasses, she has difficulty reading, and recognizing faces and often forgets names and appointments.
Visual Acuity: Marja's vision has declined due to presbyopia and age- related macular degeneration. She requires glasses for both near and distance vision but still struggles with small print and details.
Cognitive Function: Marja experiences frequent memory lapses and struggles with tasks like following recipes or managing finances. Simple activities feel overwhelming and frustrating.
Impact:
Marja's challenges have impacted her ability to engage in activities she once enjoyed, leading to feelings of isolation and sadness.
Management: Marja's healthcare team recommends: regular vision check-ups and cognitive evaluations. She is encouraged to engage in stimulating activities to maintain cognitive function.
Brain exercises to improve memory, cognition and creativity
Meditation
Visualizing
Playing games- Playing card games or board games
Playing memory card games- activate areas related to pattern recognition and recall
Practicing crossword puzzles
Completing jigsaw puzzles- puzzles activate many cognitive functions
Playing sudoku- better cognitive function
Playing chess and checkers
Playing video games
Socializing
Learning new skills
Increasing personal vocabulary
Learning a new language
Listening to music
Learning a musical instrument
Taking up engaging hobbies
Exercising regularly
Dancing
Practicing tai chi
Peripheral and Dynamic Visual Acuity
Peripheral Vision (PV)
PV is crucial for situational awareness, navigation, and detecting objects in the environment.
PV tends to remain relatively stable with age compared to central vision.
The decline in PV acuity is gradual and varies among individuals. Collins, Brown, and Bowman (1989)* reported that changes begin around age 54.
A slight reduction in sensitivity to low-contrast stimuli and decreased ability to detect fast-moving objects in the peripheral field. This occurs around age 64.5 Cassini, Brown, and Bowman (1988)*
The size of the visual field decreases by approximately 1 to 3 degrees per decade of life.
By the time individuals reach their 70s and 80s, peripheral visual field loss can range from 20 to 30 degrees.
Can we train and expand our peripheral visual field before aging? Awareness Chart & Vision Disk
Dynamic VA and Age
It is the ability to detect objects when they are in motion ( 1953 Ludvighy Miller)*
Dynamic visual acuity is modulated by the contrast between the stimulus and the background on which it moves (Zhan, Yager, Lee and Bichao, 1994) *
VA of a subject is reduced as the speed of movement of objects increases (Aznar- Casanova et al., 2005) *
This becomes increasingly difficult as people age (40 years old starts the deterioration), (Long & Crambert, 1990)—even faster than the decline of static visual acuity (SVA; Burg, 1966; Ishigaki & Miyao 1992).
More under low illumination or high glare conditions
The sustained practice of martial arts such as judo or karate attenuates the decline of DVA Miller et al 2022; Muiños & Ballesteros ,2015* neuroplasticity in the aging human brain
Other Impacts of Visual Acuity Decline in Older Adults
Reduction in VA in older adults could:
Increase risk of 5-year mortality
Increased risk of nursing home placement
Increases hospital length of stay in by two days
Increase risk of falls
Increase risk of hip fracture
50% of low vision patients have clinical depression
Increase risk of social isolation
Decrease in physical activity
Summary - Visual Acuity
Stable from about age 20 to 45
Declined with age (normal)
The greatest decline after the age of 60
Largest drop occurring between ages 70 and 80
Factors that contribute to decline:
Changes in flexibility and transparency of lens and image
Changes in pupil
Peripheral visual acuity is reduced around age 54
Dynamic VA starts deterioration around 40 years old
VA may be used in combination with other screening measures to determine risk for cognitive decline