They might be a window to our soul, but our eyes are also a good indicator of our overall wellness. Optometrist ANDY MEAU of iSight Optometric Eye Care Centre tells us how an eye test can also be a health check. Plus, he outlines 10 issues that can be identified during a comprehensive eye examination.
#1 Discover symptoms for diabetes
Diabetic retinopathy is a leading cause of blindness. In the early stage of the disease, small blood vessels in the retina are damaged causing microaneurysms or small haemorrhages. As it progresses, abnormal growth of new, weak blood vessels can lead to fluid leakage and swelling of the macula, causing potential irreversible vision loss.
During an eye examination, an ophthalmoscope is used to examine the retina. In the early stage of diabetic retinopathy, there will be signs of yellowish lipid deposits. These are known as exudates, or cotton-wool spots (the swelling of nerve endings). In more advanced stages, we may observe blood leakages, vitreous haemorrhage or retinal detachment.
#2 Elevated blood pressure (hypertension)
Elevated blood pressure can lead to changes in the appearance of the vasculature in the retina. In hypertensive retinopathy, there is narrowing of the arteries, indentation of the veins by the crossing of arteries (nicking) and increasing tortuosity of the blood vessels. Similar to the damage to the blood vessels in diabetic retinopathy, retinal haemorrhages, microaneurysms and cotton-wool spots are commonly spotted. If the central macula is involved, there will also be vision loss.
#3 High cholesterol in an eye test
Atherosclerosis due to high cholesterol can lead to the formation of small yellowish plaques. Known as Hollenhorst plaques, they can travel to the retinal blood vessels. If these plaques lodge onto the small blood vessels in the retina, sudden transient loss of vision in one eye can occur. This lasts around five to ten minutes.
Another sign of elevated cholesterol level is lipid plaque formation (xanthelasma) near the inner angles of both eyelids. A more common sign is a greyish/blueish ring of lipid deposit that encircles the perimeter edge of the cornea, called arcus senilis. The appearance of arcus in young adults could be an indication of elevated cholesterol levels.
#4 Health check for thyroid disease
Complications in the eyes from disorder of the thyroid gland are common and may even appear before systemic symptoms. Usually, it’s due to an overactive thyroid gland, hyperthyroidism or Graves ophthalmopathy. The following clinical features are typically seen in this disease: protrusion of the eyeballs (exophthalmos), one eye appearing bigger or showing more white than the other (lid retraction), seeing double, and dry eyes.
#5 Rheumatoid arthritis
Rheumatoid arthritis is a chronic inflammatory disease that primarily affects the joints. However, it occasionally affects other parts of the body, including the eyes. Patients may present with dry eyes, pain or redness associated with an inflamed conjunctiva (the layer on the surface of the white part of the eye). In some cases, the dryness can be so severe that vision becomes blurry.
#6 Multiple sclerosis
In cases where young adults between 20 to 40 years of age present with symptoms of vision loss in one eye, changes in colour appearance or eye pain, a detailed eye examination of the optic nerve – a cranial nerve that carries visual information from the eye to the brain – is required. Optic neuritis, inflammation of the optic nerve, is a common early symptom of multiple sclerosis. The optic nerve may appear to be swollen and pale during an ophthalmoscopy. The pupil reflex and reaction between the two eyes may also be abnormal. These patients are referred to neurologists for further investigation.
#7 Myathenis gravis
This is a chronic autoimmune neuromuscular disorder characterised by weakness and fatigue of skeletal muscles. It’s due to a breakdown in the normal communication between nerves and muscles. Eye muscles are often the first to be affected in this disease. Patients with MG will usually present for a health check with droopy eyelids in one or both eyelids, seeing double, or difficulty in moving the eyes in certain directions. These symptoms can have a significant impact on the quality of life, causing difficulties with reading, driving or working. Ocular MG may be a precursor to generalised MG affecting other muscle groups in the body.
#8 Brain tumour
Visual information received by the eyes travels along the optic nerve at the back of the eyes. Then all the way to the visual cortex located at the back of the head. Any abnormal growth or tumour that presses anywhere along this pathway can cause visual field loss, blind spots or peripheral vision loss. During an eye test, a person’s gross visual field is routinely tested to determine any field loss. Also, if there is a tumour or growth located near the back of the eye, we would see swelling of the optic nerve head at the retina level during an ophthalmoscopy.
#9 Stroke
When we refer to stroke, we’re referring to a cerebral event where there is brain tissue damage due to burst blood vessels in certain areas of the brain, or a lack of blood flow to certain areas because of blocked blood vessels. By looking at the retinal blood vessels during an eye examination, we’re able to identify individuals who might be more likely to have a stroke in the future. Blood vessel changes include thickening or narrowing of blood vessels, or leakage of blood from the blood vessels in the retina. These individuals would be reminded to have regular body checkups with their family doctors in order to prevent or lower the risk of any future stroke.
#10 Vitamin A deficiency
Our own body cannot produce vitamin A on its own. So it must be obtained through food sources that are rich in carotenoids. Foods such as orange vegetables (carrot, sweet potato, pumpkin, squash), orange fruits, liver, oily fish, milk and cheddar cheese are some examples. By consuming these foods, our body is able to convert carotenoids into vitamin A. Some gastrointestinal diseases can affect the absorption of vitamin A such as celiac disease or liver cirrhosis. Symptoms of vitamin A deficiency vary in severity in different people. But most of them will have some form of night blindness (trouble seeing in low light), or a build-up of bitot spots in the eyes that can cause hazy vision.
A health check using an AI eye test
Our eyes are the only part of our body where blood vessels and nerves can be observed directly and non-invasively. Any changes to the blood vessels and nerves in our retina can be an indication that the same changes are happening in our brain and other parts of our body. By observing and documenting these changes, we can detect systemic diseases or determine the risk of developing them.
Advances in digital technology allow us to take detailed photos of the retina. We can also perform scans in the deeper layers of the retina to identify abnormalities. These images and scans are useful in monitoring changes and progression of diseases.
In the last few years, this process has been used in conjunction with artificial intelligence systems to help us detect and identify changes that may not be possible with our naked eyes. Machine learning of hundreds of thousands of retinal images allow the AI system to learn and differentiate what is normal and what is not. It can also recognise particular signs of change that can indicate an increased risk for certain diseases, such as those listed above.
It’s important to stress that these systems are currently not used for making definitive diagnosis. Instead, they help us to identify individuals with a higher level of risk. Together with a comprehensive eye test, optometrists can make better management plans to help our patients to live healthier lives.
To make an eye examination appointment at iSight call 2521 6060 or visit isight.com.hk/book-online. Alternatively, visit the centre to book an eye test at Room 1002-03 Loke Yew Building, 50-52 Queen’s Road Central.
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This article first appeared in the Winter 2024/2025 issue of Expat Living magazine. Subscribe now so you never miss an issue.
