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Alter your vision exam for Alzheimer’s patients
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Alzheimer’s disease is essentially a significant form of dementia, and examining and treating these patients requires adequate planning for their special circumstances. In an interview with Primary Care Optometry News, Patricia Minor-Tolar, LDO, ABOC, NCLE, president of the International Opticians Association, said, “These patients sense that they are different but they can’t quite figure out why. Therefore, I just try to make them feel comfortable. I talk to them as plainly as possible.”
Ms. Tolar, whose mother lives at an assisted living facility, is a patient advocate for the Alzheimer’s unit. Because of this, Ms. Tolar has daily contact with Alzheimer’s patients. “Most optometrists and opticians don’t deal with this,” she said. “One optometrist said that in 20 years he’s probably seen four Alzheimer’s patients that he was aware of, because a lot of times they don’t specify. They just seem like old people, especially in the beginning stages.”
What to expect in the exam
Primary Care Optometry News “Neuro Connection” columnist Leonid Skorin Jr., OD, DO, discussed the vision exam. “Alzheimer’s can affect the visual system in various ways,” he told PCON. “Although many such patients may complain of blurred vision, reading difficulty and a generalized inability to see, unless there is an obvious organic problem, such as cataract or macular degeneration, most have a normal visual acuity.”
Dr. Skorin explained that obtaining an accurate visual acuity may be demanding due to patients’ difficulty with identifying numbers and letters. To solve this dilemma, Dr. Skorin uses a tumbling E chart. He also finds that later-stage Alzheimer’s patients develop color vision and contrast sensitivity impairment.
“Visual field sensitivity is also reduced, and studies have shown that visual field deficits are most pronounced in the inferior field — affecting the patient’s ability to read and do near work. This is a compounding problem when added to the cognitive comprehension dementia,” Dr. Skorin said.
“I don’t think as the stages advance that they can read,” agreed Ms. Tolar. “I don’t think they understand exactly what’s going on. A lot of them watch television, but I have never seen anybody reading at any of the stages.”
Eye movement is not as affected in patients with Alzheimer’s disease as it is in patients with Parkinson’s or progressive supranuclear palsy, Dr. Skorin said. Focusing problems seem to be closely related to the degeneration of the parietal lobe of the brain. “Saccades can be affected through delayed latency, reduced velocities (the degree of reduction correlates with the severity of the dementia), inaccurate saccades or difficulty in initiating or maintaining saccadic eye movements,” he said. “Smooth pursuit eye movements may also be affected.”
Contributing to Alzheimer’s patients’ inability to recognize faces, a common symptom of the disease, is poor performance at lower spatial frequencies with contrast sensitivity function tests.
“Objective testing is necessary if they are unresponsive,” added Peter Shaw-McMinn, OD, whose private practice is located within an over-55 community. “These patients have good days and bad days. Sometimes all appears OK; other days they are completely unresponsive.”
Cataract surgery can help
“Because contrast sensitivity can be adversely affected by cataracts, I encourage the patient and his or her family members to consider cataract surgery,” Dr. Skorin said. “I can usually perform surgery on many of these patients under topical anesthesia with the added help of taping their heads to prevent any sudden head movements and a ‘vocal local’ — talking these patients through their surgery. I let them know exactly what I am doing in a calm, reassuring voice.”
Except in cases of advanced dementia where Dr. Skorin would use general endotrachial anesthesia, “I let the anesthetist know ahead of time not to give any sedating intravenous medications, because I want the patient as alert and cooperative as possible during the surgery,” he said.
Neuro-ophthalmic findings
Before any other symptoms of dementia appear, a Balint-like syndrome can be found, which Dr. Skorin says is a combination of neuro-ophthalmic, visual symptoms that include:
- Simultanagnosia — the inability to perceive more than one visual target, such as being unable to report all items or their relationships in pictures depicting events or situations.
- Optic ataxia — muscular in-coordination, with the inability to reach for objects of interest.
- Psychic paralysis of gaze.
“These symptoms are often accompanied by visual field constrictions, the fading of centrally fixated objects and impaired reading capacity despite normal visual acuities,” Dr. Skorin said.
Vision correction selection
Through their experiences, Dr. Skorin and Ms. Tolar have compiled useful practical tips for treating Alzheimer’s patients. “All of these patients will benefit from optimum refractive error correction with possible separate glasses for distance and reading, because ocular motility through a bifocal or trifocal lens may be difficult,” noted Dr. Skorin.
Dr. Skorin also suggested keeping the environment visually rich as a tool to assist cognition and correction of any underlying ophthalmic pathology, such as cataract, to improve the patient’s ability to see clearly. Specifically, Dr. Skorin mentioned having a lot of color and contrast in their living quarters including flowers, paintings and photographs.
John W. Potter, OD, FAAO, vice president for clinical services at TLC Laser Eye Centers, also offered some advice. “Intermediate vision is probably more important than distance or near,” he said in an interview. “Also make sure the obvious conditions such as cataract and age-related macular degeneration are not present. Don’t assume everything in the patient’s life comes from Alzheimer’s disease.”
Dr. Potter advised communicating the patient’s condition clearly to his or her caregiver. In his experience, caregivers are often unaware of significant distance or near refractive errors (such as 3 D of myopia or + 5 D for near in reading lenses) and what their correction mean to the patient.
He recommended one prescription with both distance and intermediate correction. “These patients have no trouble with progressive lenses in my experience, so one prescription is pretty easy to use,” he said. “Good intermediate vision will keep the patient from falling or missing a step. Their entire world is within arms’ length to 10 feet or so.”
“I have seen that physically they tend to be doing better than their spouse,” stated Dr. Shaw-McMinn. “It is only mentally that they have problems.”
Ms. Tolar is a proponent of annual vision exams for Alzheimer’s patients as a way of catching change at an earlier stage and keeping prescriptions up to date. “If we take some adequate steps to prevent the unnecessary visual impairments, it would prevent or limit some of their dependence on others — maybe even reduce the burden on the nursing staff,” Ms. Tolar said. “It would improve the patient’s overall quality of life.”
Dr. Shaw-McMinn agrees. “It is difficult to ascertain what they are capable of when seeing them only occasionally,” he said.
When choosing a frame design, Ms. Tolar emphasizes letting patients choose for themselves. “If they like the red frames, they won’t lose them so easily.”
“They should be treated like a child in the more advanced stages of the disease,” she continued. “They should be given the polycarbonate lenses and the safest and sturdiest frame for the eyeglasses that you can provide.” She also recommends having a spare pair in a safe place, as chances are great they will be lost. Label both pairs of glasses with the patient’s name.
“I do not see aggressive behavior as in some disorders, but rather docile behavior,” added Dr. Shaw-McMinn. “Educating the caregiver is as important as trying to educate the patient. The Alzheimer’s patient will not remember instructions and may not recall the entire exam experience.”
For more information:
- Patricia Minor-Tolar, LDO, ABOC, NCLE, has been a private practicing optician for more than 30 years. She can be reached at PO Box 5185, Chapel Hill, NC 27514; (919) 968-6790; e-mail: pmtolar@aol.com.
- Leonid Skorin Jr., OD, DO, FAAO, FAOCO, can be reached at the Albert Lea Eye Clinic, Mayo Health System, 1206 W. Front St., Albert Lea, MN 56007; (507) 373-8214; fax: (507) 373-2819; e-mail: skorin.leonid@mayo.edu.
- Peter Shaw-McMinn, OD, can be reached at Sun City Vision Clinic, Sun City Medical, Dental & Vision Center, 27830 Bradley Rd., Sun City, CA 92584; (951) 672-4971; fax: (951) 780-4807; e-mail: vispros@pacbell.net.
- John W. Potter, OD, FAAO, is a member of the Primary Care Optometry News Editorial Board. He can be reached at 18352 Dallas Pkwy., Ste. 136, Dallas, TX 75287; (972) 818-1239; fax: (972) 818-1240; e-mail: john.potter@tlcvision.com.