Dementia and Eye Health - Causes, Diagnosis, and Precautions

Introduction

Dementia is considered a major neurocognitive disorder, which means there is decreased mental function due to medical diseases other than psychiatric illness. It is characterized by a decrease in multiple cognitive abilities, such as learning, thinking, reasoning, problem-solving, and decision-making capability, which is acquired rather than developmental.

All types of dementia have the exact molecular mechanisms responsible for the cause and progression of things like:

1. Hypoxia (inability to deliver oxygen to tissues either due to low blood supply or because of low oxygen amount in the blood).

2. Oxidative stress (imbalance between free radicals and antioxidants).

3. Neuroinflammation (inflammatory response within the brain and spinal cord).

4. Mitochondrial bioenergetics and neurodegeneration.

5. Blood-brain barrier permeability.

Dementia is most commonly seen in elderly individuals. Advancing age is a risk factor for dementia. Comorbidity can further lead to the condition. Statistics depict that almost 47 million people live with dementia all over the world, and by 2050 there will be a threefold increase, and the number will turn to 131 million. Vision problems, vision loss, and blindness can be one of the first signs of dementia. When the visual pathways are not stimulated, dementia can progress more rapidly and lead to more troubles. Dementia often causes vision problems and can interfere with daily living and activities, including:

• Reading will be difficult.

• There will be difficulty with facial recognition.

• Patients develop disinterest in hobbies and daily activities.

• Difficulty locating and finding objects.

• There will be uncoordinated body movements seen in patients who have dementia.

If any of these behaviors are noticed, it is advised to consult a physician for treatment and to have a good outcome.

What Are the Causes Associated With Dementia and Eye Health?

• Cataracts (clouding of the lens) are almost 11 % higher in cataract patients.

• Macular degeneration can also lead to dementia.

• Other health conditions include stroke (when the blood supply to the brain is reduced).

• Normal aging of the eye can also impact the condition.

• It is seen with patients suffering from ophthalmic and systemic conditions such as diabetes, heart disease, and depression.

• It is also observed that patients with at least two ophthalmic conditions were at higher risk for dementia than those with one ophthalmic disease. Patients with at least two ophthalmic and at least two systemic conditions were almost three times more likely to develop dementia.

Could Dementia Affect the Eyes?

Alzheimer's disease is a disease caused by the death of brain cells. It causes dementia, and the abnormal building of proteins in the brain kills cells called neurons. It also deteriorates connections between the neurons. It is characterized by loss of memory, difficulty in thinking, disorientation, and other kinds of cognitive decline (normal aging that causes dementia). In addition, patients may present with symptoms such as problems in vision, especially trouble with spatial relationships (understanding how objects move towards one another) and depth perception. There are also problems related to difficulty in reading, following moving objects, and contrast issues.

There are different types of dementia.

1. Alzheimer's Disease: Alzheimer's disease is the most common one. 60 to 80 % of dementia is because of Alzheimer's disease. There are other types as well that include vascular dementia, which is associated with stroke (when the blood supply to the brain is compromised), dementia associated with Lewy bodies (a disease associated with abnormal deposits of proteins), and frontal lobe dementia (a progressive brain disease).

2. Parkinson's Disease and Huntington's Disease: Parkinson's disease and Huntington's disease (the degeneration of nerve cells in the brain) can also lead to dementia. There is mild cognitive impairment in older age, which worsens with time. It can be seen in the early stages of Alzheimer's disease.

Alzheimer's disease is diagnosed after a proper assessment and ophthalmic examination. These tests include cognitive testing for memory and thinking, talking to family members, physical examination, and brain imaging scans.

How to Diagnose Dementia and Eye Health?

• Changes are associated with the retina in people with Alzheimer's or other forms of dementia. There is a change in individual layers of the retina or blood flow within the eye.

• Optical coherence tomography (OCT) is a quick and standard test to see changes in the retina.OCT is also used to see other eye conditions as well.

• A new imaging technique called fluorescence lifetime imaging ophthalmoscopy (FLIO) is also used to diagnose the condition. FLIP helps in the measurement of a protein called beta-amyloid in the retina. This is a protein that gets built up in people who have Alzheimer's disease. Studies also indicate eye tissue changes in people with other brain diseases such as Creutzfeldt-Jakob (mad cow disease). It is a degenerative brain disease that leads to dementia and Parkinson's disease (a brain disorder that causes uncontrollable body movements).

What Are the Precautions to be Taken to Prevent the Condition?

Many precautions are required for someone living with both sight loss and dementia. These include:

• Good eye care is essential that is done by having regular eye tests and also the use of correct glasses that are clean and correct.

• Improve the lighting, using contrasting colors and keeping areas clutter-free.

• Encourage patients with dementia to communicate with body language and physical contact.

• Technology and equipment can also help, such as automatic lights or audio labels. Automatic lights and audio labels increase safety and reduce the risks of accidents and falls.

• Seeking support from ophthalmologists and health care workers.

• Develop strategies and also ensure the optical prescription is up-to-date.

Conclusion

As visual loss is concerned, cataracts and diabetic retinopathy are associated with an increased risk of dementia. Early diagnosis and management may help in identifying dementia. Most of the causes are treatable or preventable in the case of visual dementia. Proper investigation and tests are required to diagnose dementia. The relationship between brain tissue and eyes is an area of interest for ophthalmologists and neurologists. The brain plays an essential role in taking visual information, the eyes put it together into a picture, and the optic nerve connects the brain to the back of the eye.