The University of California, San Diego, has just developed a smartphone application capable, immediately and simply, of detecting the early signs of several neurological disorders, including Alzheimer’s disease. How ? Through the phone’s camera, which is able to track changes in a person’s pupil size at sub-millimetre resolution. Analysis of these measures can then be used to assess his cognitive state.
The idea is not new and, as technologies evolve, the eyes will always prove to be more relevant for diagnosing a wide range of diseases. Indeed, due to their partial transparency, they require much less invasive examination methods than other parts of the body.
Without any technology, just by looking yourself (or your loved ones) in the eye, you can detect a number of benign health problems yourself – but not only. Here are the concrete examples of some characteristics that you can analyze.
Pupil dilation abnormality
The pupil, this “black hole” at the heart of our eye, reacts instantly to light thanks to the iris (colored part, made up of muscle fibers) which is able to contract or expand like a camera diaphragm.
It adapts by becoming smaller in bright environments and larger in darker ones. This pupillary (or photomotor) reflex is commonly checked by health professionals.
A slow or delayed pupil size response can be a sign of several diseases, including serious illnesses like Alzheimer’s disease, as well as the effect of medications and drug use. Dilated pupils are common in people who use stimulant drugs, such as cocaine and amphetamines. Very small pupils can be seen in heroin users.
Color of the “white of the eye”
A change in color of the sclera (the “white of the eyes”) indicates that something is wrong…
A red, bloodshot eye can, for example, be triggered by alcohol or drug abuse. It can also be caused by irritation or infection, which in most cases goes away within a few days.
If the color change is persistent, it may signal a more serious infection, inflammation, or a reaction to contact lenses or their solutions. In extreme cases, a red eye indicates glaucoma, a condition that can lead to blindness.
Sclera turning yellow is the most obvious sign of jaundice (jaundice) or other liver damage. The underlying causes vary widely, and this yellowing of the skin and eye is due to excess bilirubin (yellow pigment) in the blood when it can no longer be excreted normally by the liver. They include inflammation of this organ (hepatitis), genetic or autoimmune diseases, as well as certain drugs, viruses or tumours.
A small red spot in the white of the eye, witness to a subconjunctival hemorrhage – or a small blood vessel that has “snapped” locally – can be frightening. Most of the time, there is no reason to worry: the causes are rarely clear for this phenomenon and the bleeding generally disappears within a few days.
However, it can also be an indication of high blood pressure, diabetes, and blood clotting disorders that cause excessive bleeding. Blood-thinning medications like aspirin can also cause it. Also, if this problem is frequent, it may suggest that you need to limit your intake of these drugs, or at least review the dosage.
Appearance of a clear arc
It is a common feature after a certain age, hence its scientific name of arcus senilis (or senile arc of the cornea, gerontoxon): a lighter “arc”, sometimes almost white, can form on the periphery of the cornea.
It is due to a deposit of cholesterol… but is not necessarily the sign of hypercholesterolemia, and it does not reduce visual acuity. In some cases, however, it may actually be linked to high cholesterol and an increased risk of heart disease. It can also reveal alcoholism.
Development of a small fatty bump
Sometimes the most alarming features that can appear on the eyes are actually the most benign and easily treated.
A small yellowish cystic bump may appear on the white of the eye: this is a pinguecula, a deposit of fat and protein. This small lesion (which may be caused by exposure to dusts, etc.) may be accompanied by mild inflammation and irritation. Not causing visual discomfort, it does not necessarily require treatment. But if the inflammation sets in, it can be easily cured with eye drops or removed with a minor operation.
The pterygium (or pterygia) also comes at the level of the sclera, but the impact is not the same. This time it is an evolving pinkish growth that covers the white of the eye; it is not a sight hazard until it begins to encroach on the cornea.
Fortunately, its development is very slow. And like the pinguecula, it can be easily removed. In fact, it must be removed long before it reaches the cornea. If left to settle, the pterygium will form an opaque “film” on the cornea which will obstruct vision. One of the main factors causing the pterygium (as with the pinguecula) would be chronic exposure to ultraviolet rays from the sun.
Eyes that become more protruding
It’s a feature of the face: the eyes can be more or less sunken, spread apart… Some people have more bulging eyes than others. But sometimes this feature evolves and there is a tendency of the eyes to project forward (we speak of exophthalmos). The eye appears to “grow”, which is due in particular to an increase in the eye muscles; if the phenomenon is accentuated, visual discomfort is possible, with pain, poor hydration of the globe, etc.
The cause may be medical and require special attention. It can be the consequence of an infection (the most common cause in children), an injury, an inflammation (linked to a fungus, an abscess, etc.), a tumor behind the eye (very rare), etc. But the most common origin is a problem with the thyroid gland (80% of these thyroid cases stem from hyperthyroidism), which triggers inflammation of the eye tissues and causes them to swell. She then touches both eyes.
What the eyelids say
The eyelids can also indicate many diseases. These are usually related to minor ailments of the glands associated with them.
A stye, for example, is a common and inconsequential infection of the base of an eyelash by bacteria, which causes swelling and localized reddening. It usually goes away on its own or with warm compresses; in case of persistence, it can be removed by a simple procedure. The chalazion, which appears as a red bump on the upper eyelid and, more rarely, on the lower eyelid, is due to an obstruction of a sebaceous gland.
Spasms and involuntary contractions of the eyelid (myokymia) will irritate, annoy – but in most cases, the phenomenon is perfectly harmless and is more unpleasant than dangerous. It can be linked to stress, a nutritional imbalance or excessive caffeine consumption.
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