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What Every Optometrist Should Know About the Aging Eye
To Gain an Understanding of Systemic Biological and Physiological Changes with Aging
To Gain a Background in Medical Aspects of Geriatrics in Regard to Systemic Diseases
To Appreciate the Impact of Geriatrics on the Practice of Optometry
To Gain Insights for Improving Eye Care to Geriatric Patients
* The goal of this continuing education presentation is to cover the topic of "biological and physiological changes during the aging process and the various systemic diseases associated with the aging process that are important in caring for the aging patient in the practice of optometry." In a course such as this, only a brief overview of ocular diseases associated with aging are able to be covered due to specific disease complexity. Because we are all aging, if you are not interested in this topic you are in big trouble!
Definition: Geriatrics - the branch of health care that deals with diseases of the elderly. However, there is no good way to draw an age line at which a person becomes a geriatric patient because of the extremely wide variation from individual to individual during the aging process. It is not at all uncommon to simply use reaching the age of 65 and over the age of 65 to define when a person is considered to be a geriatric patient. It is not at all uncommon to see patients in their early 40’s with signs of significant aging nor is it uncommon to see patients in their 60’s and 70’s that seem to be quite young for their chronological age.
Figure 1: 95 year old woman holding a five-month-old boy
It is important for the practicing optometrist, as well as for all other health care providers, to have a basic understanding of the biological and physiological aspects of aging. This course also will include a review of various medical aspects of aging and stress the impact that an aging population will have on the practice of optometry.
Life expectancy is theoretically projected to be 120 Years by evidence conducting scientific research on human cells and cellular life span. However, at this time it is only about 75 years for men and about 80 years for women!
Question: Where Do The Other 40 Years Go??? The other 40 years go away due to adverse affects on the human genetic apparatus and environmental impact from toxins, oxidants, etc. cellular damage.
It is obvious that clinicians by visual inspection during the greeting of patients clinically begin to assess the patient’s chronological age. The young patient has smooth, elastic, wrinkle free skin and the elderly have many wrinkles and baggy skin due to loss of elasticity. Also other tell-tale signs such as grey hair, loss of hair, dress, speech, etc. offer tell-tale clues for a best guess at the age of the patient.
Polygenic as a concept is important for aging as well as all other diseases and disorders and the definition is the combination of genetic predisposition to diseases and disorders, including aging, coupled with environmental factors that “trigger” the disease or disorder.
My old college roommate from 1960-64 and I were backpacking on the Pacific Crest Trail and were about 4 days of a difficult hike from civilization when he told me that he had something he needed to tell me….and that was that he needed to have surgery on an artery in his neck when we finish the 15 day hike in the High Sierras. On further questioning, he had seen his optometrist a couple weeks prior to this hike for a follow-up contact lens evaluation and to get new contact lenses.
At ophthalmoscopy his optometrist noted something very similar to the following abnormality. See Figure 2.
Figure 2: Hollenhorst plaque (bright spot) blocking a retinal arteriole
He is 66 years old, on no medications and his history is totally benign with absolutely no symptoms. He is a heavy exerciser and a runner, backpacker, mountain climber, etc. outdoorsman. He recently returned from Mt. Everest base camp and had no symptoms when he was at almost 20,000 feet elevation on Mt. Everest and on no oxygen, etc. support. Recall I learned of his “problem” while backpacking. See Figure 3.
Figure 3: The author (in blue) and the patient (in red), mountain-climbing
His family history is that his father died of a heart attack at age 64 and his mother died of a stroke at age 65. He has one brother age 70 who is also “healthy” and asymptomatic.
Question: What is the lesion, why did it occur and what does an OD do when discovering such an asymptomatic lesion?
The diagnosis in this case is an Asymptomatic Hollenhorst Plaque. The origin of the plaque is from an atheroma in the carotid artery circulation at the junction of the Common Carotid where it bifurcates into the external and internal carotid arteries.
The OD referred the patient to a Vascular Surgeon and work-up included documentation of a normal blood pressure and other physical examination including no bruits in the neck. Laboratory evaluation revealed a normal cholesterol and other blood chemistries. Ultrasound and Magnetic Resonance Angiogram of the Carotid System were conclusive for the diagnosis of a major obstruction at the junction of the Common Carotid bifurcation to the Internal and External Carotid Artery. See Figure 4.
Figure 4: Doppler ultrasound of atheroma (left) and MRA (right)
The patient was placed on a baby aspirin per day and scheduled for surgery at the end of the hike. Without symptoms he finished the hike, underwent uneventful surgery to remove the atheroma and was back to normal very quickly.
Atheromas occur in everyone beginning in infancy and are part of the normal aging process. However, these lesions occur earlier and develop more rapidly in the presence of Diabetes Mellitus poorly controlled, uncontrolled hypertension, high Cholesterol, Thyroid Disease (both hypo and hyper), etc.
Also important is age and genetics!! Yes, family history is critical and in this case there were no apparent underlying problems except approaching age 70 and a family history of vascular disease.
Final diagnosis in this case is atherosclerosis due to a family history of the disease and the aging process.
More on vascular disease is presented later in this course.
Demographic Shift - In the year 1880, only about 3% of the USA population attained age 65 or over. By the year 1900 this age group represented about 4% of population and in the 2000’s the over 65 age group is the fastest growing of all age categories with the over 85 age group being the very fastest growing in numbers. As of the year 2010 the over age 65 group makes up approximately 12+% of the total USA population. By the year 2030 the percentage of the USA population for the 65 years of age and over will increase to in excess of 20% of the total!
The care of the elderly is a multi-billion dollar industry due to increased needs for all aspects of heath care including nursing home care, home health care, medications for chronic diseases, hospitalizations for accidents and acute health related problems, chronic medical problems (diabetes, hypertension, vascular diseases, cancer, etc.), surgical problems (especially cardiovascular and cancer), vision changes (especially cataract surgery, macular degeneration and other age related changes), mental changes (Alzheimer’s Disease, depression, etc.), and the list goes on and on!!
This 12+% of the population classified as geriatric, well over 30,000,000 people in the USA, accounts for over 20% of the USA population classified as impoverished. However, it is important to understand that only about 5% of the geriatric population is in institutions such as nursing homes which means that 95% of the population classified as geriatric is out in the community in which they reside.
The population classified as geriatric is expected to increase to well over 20% in next 20+ years and therefore it is estimated that there will be over 45 million geriatric patients living in the USA by the year 2020.
B. In 1880, the average life expectancy from the time of birth was only 45 years of age. By the year 1900 life expectancy from the time of birth increased to 47 years. Now in the twenty-first century life expectancy from the time of birth is over 75 years for males and 80 years for females. There are several theories on why life expectancy is less for males than for females and this will be discussed later in this course.
C. At the present, patients over the age of 65 consume more health care dollars per capita than any other age group. This 12+% of the population use approximately one-third of all hospital beds and take one-fourth of all medications prescribed and, therefore overall, consume about one-third of all the health care dollars spent in the USA.
D. Problems associated with the aging process:
1) Physiologic changes: There is a steady decrease in the cell mass of all vital organs with resultant concomitant decrease in organ function and reserve capacity in case of injury or loss.
2) These “normal” changes coupled with a large number of chronic diseases and the very high incidence of psycho-socio-economic problems in the geriatric population means that there is an increased incidence of malnutrition, alcohol abuse, depression, suicide, etc. with this age group.
E. It is an established fact that significant aging changes begin about age 30 and these changes due to aging slowly continue at a fairly constant rate throughout the remainder of a person’s life. However these changes due to aging occur at different rates in different individuals for many reasons including environmental insults and predisposition to aging changes on the person’s genome (DNA). It also has different meanings for different people according to physical needs. For instance, professional athletes often become “too old” to compete in their 30’s and 40’s especially due to changes due to the normal aging process in the neurological system, cardiovascular system and respiratory system.
BIOLOGY OF AGING
1. Definition - The physiologic changes associated with the aging process irrespective of any concurrent acute or chronic disease process. Primary aging is due to a much more complicated process than simply the "dying of cells" in body organs and it is a known fact that good mental health, participating in proper exercise programs and maintaining good dietary habits can all help to slow the primary aging process.
2. Keep in mind that beginning about the age 30 there is a definite, steady, progressive loss of function of all body organs even in the most healthy of patients.
3. Another important fact is that primary aging does not tend to become significant until sometime around age 65 to 70 years.
4. It is also a fact that all vital organ function decrease linearly with the aging process and this is most apparent in the cardiovascular system and the pulmonary system which are discussed in detail later in this presentation.
5. The immune system decreases in function in the aging process. The cellular immune system as opposed to the antibody-medicated system is being most severely affected by the aging process.
6. For all health care providers it is critical to know that liver and Kidney function diminishes with age. About the age of 70 both liver and kidney function is only about half the level of the function of these vital organs as it was at age 20-30.
7. On a microscopic level, age correlates very well with intracellular lipofucin accumulation due to cell damage over time. This is microscopic evidence of the aging process that can be observed on tissue biopsy.
Primary Aging leads to decreased homeostatic reserve in all body organs and, therefore, the elderly cannot tolerate the various disease stresses on vital organs nearly as well as when they were younger.
*Interesting Fact: The elderly have only about one-half the acute illness incidence of young adults, however, it takes the elderly much longer to recover from acute illness due to diminished capacity of all vital organs.
B. SECONDARY AGING
1. Definition: The increased rate of changes due to the aging process that stems from the various acute and chronic diseases coupled with any of the many psycho-socio-economic problems. It is theorized that approximately 80% of any vital organ functional loss due to secondary aging is a result of poor life choices, e.g. smoking, lack of exercise, poor diet, alcoholism, poor medication compliance, depression, etc.
2. Chronic diseases such as diabetes, hypertension, etc. have mostly replaced acute illness, especially pulmonary infections, as the leading cause of death in the elderly population.
3. Often, acute illness is only the "terminal event" leading to death which has actually ensued from a chronic, progressive disease or disorder.
4. The leading diseases/disorders in secondary aging include the following: chronic cardiovascular diseases, malignancies, cerebro-vascular diseases, diabetes, rheumatic diseases and skin diseases.
5. It is well known that poor nutrition, lack of exercise, and smoking all contribute greatly to the secondary aging process.
6. Therefore all health care practitioners must encourage patients to decrease their sun exposure, stop smoking if they smoke, quit any excessive drinking, etc. in order to decrease the impact of secondary aging on their bodies. All practitioners must encourage patients to exercise, have good nutrition, be compliant on medication regimens, get regular check-ups, etc. in order to live a longer, healthier life.
7. It is important to implement good "preventative" health screening programs such as screening for metabolic diseases, cancer, cardiovascular disease, ocular diseases, etc. in order to identify patients at risk for unnecessary secondary aging.
The many health related problems that lead to an increased secondary aging rate are to large degree REVERSIBLE or CONTROLLABLE so prevention and early detection for treatment is very important.
THEORIES ON AGING AND THE AGING PROCESS
WEAR AND TEAR THEORY
This theory proposes that there is a cumulative damage to cells in vital organs and irreplaceable body parts which leads to the death of cells, tissues, organs, and finally the whole body. Therefore, the cumulative damage to cellular DNA ultimately results in a decline in cell function and cell death. The main problem with this theory is that there are no research models that give credible support at this present time.
FREE RADICAL THEORY
This theory proposes that there is a progressive accumulation of high energy oxygen species that progressively and irreversibly damages cellular components such as cellular and intracellular membranes, the cell’s genetic apparatus, other cellular substances and that this accumulated damage leads to cellular aging and the total aging process. There is credible research evidence to support this theory and human research with the use of antioxidants to control damage due to high energy oxygen species is ongoing at this time. See Figure 5.
Figure 5: Free Radical Theory of Cellular Damage and Aging
APOPTOSIS OR “PRE-PROGRAMED” GENETIC AGING THEORY
This theory proposes that the various cells of the body are genetically “pre-programmed” (like tiny computers) by an intrinsic pacemaker system that determines the life expectancy of the various body cells and therefore of the whole body. In this theory, when the cellular genetic apparatus determines that it is time to die, the cell shuts down and dies. Obviously when a critical number of cells in any vital organ dies it results in the death of the entire body.
It is well accepted that genetic factors are important determinants in the process of normal aging. However, the exact mechanism at the genetic apparatus level is unknown at this time. For instance, the life expectancy of identical twins is more similar than is observed with fraternal twins or other sibling with the same two parents.
THE POLYGENIC THEORY
This is the theory that this lecturer holds to and it seems to be the theory the researchers are coming to hold as the most likely underlying reason for aging to occur. In this theory, the powerful influence of both the genetic apparatus and the powerful influence of the many different environmental forces that impact cells of the body “add up” to cause the aging process and adversely affect life expectancy. This theory basically embraces all the above theories (A-D) and gives credence to all these factors playing a role in the aging process.