Moses many woes on his way to blindness

Moses Africanus had severe itching and had been self-medicating with steroid-containing eye drops for over a year. After reading the instructions leaflet in the eye drop package, he became worried and frightened. Could he already be on his way to blindness? He wrote to Dr. Ben to seek advice. He was asked to see an ophthalmologist immediately. He didn’t waste time, he was at the hospital the following day.

Examination revealed that he was developing an unusual type of cataract – steroid induced cataract. Out in the sun, he had a dramatic reduction of his vision but once inside the house, his vision improved. He had earlier attributed this to an unusual sensitivity to light as a result of the severe itching.

If that was all Moses’ predicament, his name would have been ‘Goodluck’ because cataracts are usually amenable to surgical intervention. Unfortunately, there are many more complications. A look at the inside of his eyes revealed evidence of structural damage to his optic nerves at the back of his eyes.

Such findings are usually associated with elevation of the pressure inside his eyes – intraocular pressure (or IOP for short). Surprisingly, his IOP was within normal limits in both eyes. He required more tests. First to confirm if the IOP readings were influenced by the thinness of the cornea which could be a complication of the steroids. Thin corneas usually give lower IOP readings and the adjusted (actual) value may be much higher. This is called Pachymetry. Then he had to do Central Visual Field test to see if the structural damage observed is in agreement with functional loss.

It is only after this that a proper diagnosis of glaucoma could be made and meaningful treatment commenced. Moses had no money for the tests!

But then there is something far more serious than glaucoma – an incapacitating and potentially blinding condition – requiring immediate attention. Moses is experiencing dry eyes. He has to use ocular lubricants several times a day. He is a real mess. With no job and no income, he has to compulsorily spend money on eye medications to make his eyes comfortable and prevent serious damage which can lead to blindness.

Why should the eye be dry? And why should it cause so much discomfort and ultimately lead to visual impairment and blindness if care is not taken? The exposed part of the eye must be wet before it can function properly. The normal lubrication is provided by tears secreted by some glands in the lids, conjunctival and accessory lacrimal glands. The tear film has three layers – the superficial oily layer, which prevents evaporation of the middle tear fluid proper.

Beneath the tear fluid proper is the mucous layer, which helps, through the blinking movements of the lid, to spread the tears evenly over the ocular surface. Thus, it can be seen that anything that affects the movements of the lid or the cells producing the three components of the tears could lead to dry eyes.

How do steroids cause dry eyes? Steroids cause pathologic alterations to the ocular surface of the eyes. In addition, they cause some changes in the tissues producing the various components of the tear film. But they are not the only causes of dry eyes. There are many other causes such as vitamin A deficiency, auto-immune diseases such as Sjögren’s syndrome, drugs such as sulphonamides and non-steroidal anti-inflammatory agents (NSAID), chronic conjunctival irritation from allergy.

It is also obvious that the exposure of ocular surfaces owing to failure of lid closure from any cause can also result in dry eyes.

To some extent Moses is lucky. If he had continued using the eye drops for a few more months, the external coats of the eye (the sclera and cornea) would have become thinner and thinner losing their rigidity and elasticity.

Being unable to withstand the intraocular pressure and hold back the contents of the eye, they would have bulged, become unsightly, ultimately melting away, and spilling their contents with complete loss of vision.

In the early stages of its use, a small bacterial infection could have passed unrecognised in its early stages until it festered and became a more serious problem.

It is therefore, obvious that there is a lot of danger in a small, seemingly innocuous yet very effective bottle of steroid eye drops. Steroids are very useful in medical practice; cheap and easily available, they are useful servants but bad masters. Once started, the tissues soon get used to them and like opium or cocaine could be very difficult to discontinue without great challenges.

On the other hand, using it continuously over time (especially without a medical doctor’s prescription) is like fishing in troubled waters. Moses has great challenges ahead of him – dry eyes, glaucoma, melting of the outer coats of his eyes, bulging of parts of the eyeballs, recurrent eye infections are all potential causes of irreversible blindness.

To be forewarned is to be forearmed. I appeal to all readers to avoid the indiscriminate use of steroid-containing medicines including eye drops.