Alzheimer’s disease was first identified by Aloysius Alzheimer, a German psychiatrist, in a published case report in 1915. The pathology includes the loss of neurons and synapses in the cerebral cortex, making it somewhat similar to glaucoma in that once the neurons are lost, they are never replaced. Amyloid plaques and neurofibrillary tangles are visible on histological sections and, along with neuron loss and cerebral atrophy in a patient with typical symptoms, are diagnostic.
Today, Alzheimer’s disease (AD) is the most common form of dementia and affects 26.6 million patients worldwide and growing, according to the American College of Physicians. Most affected individuals are older than 65 years, and as many as one in eight individuals in this age group in the United States and Europe carry this diagnosis. This means that in the U.S. and other advanced countries, the treatment of this disease is primarily covered by federal and state government insurance plans, including Medicare and Medicaid.
The economic and social burden on family members and health care payers to treat AD is extraordinary, and the global spending on pharmaceutical products alone exceeds $8 billion a year. I can attest to this burden, as my recently diseased mother (at age 94) suffered from a non-Alzheimer’s form of senile dementia. In the last 4 years of her life, the all-in cost of comprehensive care in a high-quality “Senior Memory Care Center” approached $85,000 per year.
While many ophthalmologists wonder whether the aging diseases of the eye might bankrupt our health care system, it is far more likely that AD will do it first, while at the same time financially stressing a significant number of families.
Disease and vision
Although AD develops differently in every patient, there are similar patterns in the disease presentation. In the early stages, difficulty remembering recent events is followed by confusion, irritability, mood swings, trouble with language and communication, and long-term memory loss. As the patient’s disease progresses, they often withdraw from family and society and, in many cases, become aggressive. Gradually bodily functions are lost, ultimately leading to death. On average, life expectancy after diagnosis is 7 years, with less than 5% of patients living 15 years after diagnosis.
I learned from observing my mother and her fellow residents at the senior memory care center that good visual function and hearing play a critical role in daily function. I performed refractive cataract surgery on my mother at age 70, and her ability to see well at distance and near without spectacle correction greatly enhanced her quality of life in her younger active years, but was even more important to her as she developed senile dementia. Her hearing was also good, so she could see to care for herself and hear to communicate well with family, staff and residents.
Glasses wear is very difficult for the senior with dementia, and I observed many of her fellow residents during my visits with my mother wearing the wrong glasses, usually someone else’s, no glasses with poor uncorrected vision or even glasses broken, missing lenses, ill-fitting, tilted or even worn upside down. Monovision, multifocal vision or an accommodating IOL can be an even greater quality-of-life enhancement for the more senior patient than they are for the more active younger person.
A hearing deficit also increases disability and often leads to isolation and withdrawal, and many ophthalmologists now screen for hearing deficits in their patients as well. This is an important service to our seniors.
To confirm the diagnosis of AD today, in most cases neuroimaging is used to either detect the associated amyloid beta protein deposits in the brain or the changes in brain metabolism. Neuroimaging can be structural, functional or metabolic; the diagnosis of AD requires functional or metabolic neuroimaging. Positron emission tomography (PET) scans measure emissions from radioactively labeled, metabolically active chemicals that have been injected into a patient’s vein. The emission data are computer-processed to produce images of the distribution of the chemicals in the brain.