Geriatric considerations - Visual impairment: Nursing

Visual impairment is a leading cause of disability in older adults, and it can have a negative impact on safety, social interactions, mobility, and activities of daily living such as grooming and eating. As the nurse, you’ll recognize age-related vision changes and provide patient-centered care for your patient with visual impairment.

Alright, so eye structures commonly affected by age-related changes include the eyelids, cornea, iris, lens, vitreous humor, and retina.

The eyelids, which protect the eyes and help with tear distribution, lose elasticity and tone as an individual ages. This can cause ptosis or drooping of the eyelids. If severe, ptosis can interfere with vision by obstructing the visual field. In addition, the muscles controlling the eyelids may spasm, which can cause the eyelids to turn inward, called entropion›. This can result in scratching of the cornea by the lower lashes. Other times, the muscles can weaken, which allows the eyelids to turn outward, called ectropion. This can lead to dry eyes due to a disruption of tear distribution and an inability to fully close the eye.

Next, the cornea, which is responsible for protecting the eye and performing the initial refraction of light onto the lens, can thicken and become less curved, losing its ability to refract light efficiently. This leads to blurry or distorted vision called astigmatism.

The iris is a circular set of muscles that sits in front of the lens. It controls the amount of light allowed into the eye through the pupil by constricting in bright lighting to allow less light in, and dilating in low lighting to allow more light in. With age, the iris becomes less reactive, resulting in difficultly transitioning between bright and low lighting.

The lens, found behind the iris, changes its shape to focus light onto the retina. It tends to thicken and become rigid with age. In addition, the ciliary muscles, which are responsible for changing the shape of the lens, become weak. Together, this leads to decreased depth perception; presbyopia, which means the eyes have a diminished ability to focus on near objects; and impaired accommodation, which is the ability to change focus from near to far objects. Additionally, protein build-up within the lens increases its opacity; decreases adaptation to dark environments; and may eventually result in cataracts, resulting in blurry vision, glare, and diminished night vision.

Now, the jelly-like substance that fills the middle of the eye, called vitreous humor, decreases and becomes more liquid over time. This is accompanied by the formation of cellular debris which appears as floaters, that can look like dark specks or wiggly lines that move around the visual field. These are a normal and harmless manifestation of vitreous degeneration; however, an increase in the number of floaters, especially if they’re accompanied by light flashes, could mean the vitreous humor is beginning to pull away from the retina, and could eventually detach, called vitreous detachment.