Physiologic Aging and Pathologic Findings of the Aging Eye
Age-related changes in sensation and perception can isolate individuals from their surrounding environments and trigger complex psychological reactions. These changes may include diminished hearing and vision, slowed intellectual and physical response times, and increased difficulty with memory. However, many physical and intellectual abilities are retained throughout the life span, and their loss should not be assumed to be part of the normal aging process. These include the senses of taste and smell, intelligence, the ability to learn, and sexuality. Any change in physical, intellectual, or emotional capabilities may reflect underlying organic or psychological disease.
Age-related changes in the eye affect individuals differently. The periorbital and eyelid skin and soft tissues atrophy with age. Dermatochalasis and levator dehiscence may produce secondary ptosis. Eyelid laxity may cause entropion, ectropion, and trichiasis. Lacrimal gland dysfunction, decreased tear production, meibomian gland dysfunction, and goblet cell dysfunction may cause dry eye symptoms. As a result of the aging process, the conjunctiva undergoes atrophic changes and corneal sensitivity is reduced. The pupils become progressively miotic and less reactive to light. There is an increasing incidence of presbyopia, cataract, glaucoma, AMD, and diabetic retinopathy. Contrast sensitivity and visual field sensitivity are reduced. In addition, refractive error (of some type) is present in more than 90% of older patients and remains a significant cause of visual disability in the nursing home patient.
Worldwide, the 4 leading causes of vision loss in the older population are AMD, glaucoma, cataract, and diabetic retinopathy. It is estimated that by 2030, 3.7 million persons in the United States will have AMD. Glaucoma will affect 4.3 million individuals by 2030 and becomes more common with increasing age; thus, screening is recommended for patients older than 50 years. Cataract accounts for 50% of visual impairment in adults over the age of 40; it affects 1 in every 6 people in this age group. It is projected that by 2030, 38.7 million Americans will have cataracts. Diabetic retinopathy is a leading cause of new cases of legal blindness among working-aged Americans. The prevalence of retinopathy in individuals with diabetes mellitus aged 40 years and older in the United States is 28.5% (4.2 million persons), and the prevalence of vision-threatening retinopathy is 4.4% (0.7 million persons). Assuming a similar prevalence for diabetes mellitus, the projected numbers in 2050 would be 16.0 million persons with diabetic retinopathy and 3.4 million persons with vision-threatening diabetic retinopathy.
National Eye Institute website; https://nei.nih.gov/health. Accessed February 21, 2019.
Saaddine JB, Honeycutt AA, Narayan KM, Zhang X, Klein R, Boyle JP. Projection of diabetic retinopathy and other major eye diseases among people with diabetes mellitus: United States, 2005–2050. Arch Ophthalmol. 2008;126(12):1740–1741.
Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.