Problems with scleral lenses

Problems with scleral lenses

If you still want to be able to see somewhat well with keratoconus, in many cases you have to wear scleral lenses. Unfortunately, many people also experience problems with scleral lenses. They can suffer from dry and red eyes. It also regularly happens that it is not possible to use a scleral lens because this is such a large lens that also has to be filled with liquid.

Better vision with the scleral lens

The advantage of a scleral lens is the stable position of the lens on the eye. Even when blinking, the lens does not move, so that the view is very stable. The quality of vision is therefore better with the scleral lens than with a small hard (corneal) lens. The wearing comfort of the scleral lens is also very good. The edges are not or hardly felt because they are far behind the eyelids. The eyelids just blink across the smooth lens surface. And because this lens type does not touch the sensitive cornea, you would not expect any complaints with this lens. Often the problems of eye irritation with scleral lenses are attributed to a poor fit. But where can problems with scleral lenses also come from?

Possible problems with scleral lenses

Afternoon fog:
This English term stands for the clouding of the tear layer between the eye and the lens. Scleral lenses trap a tear layer between the eye and the lens. However, the tear layer is hardly refreshed during wear. The high rate of metabolism of the cornea produces large amounts of waste products that accumulate behind the lens. The cloudy tear layer creates foggy vision. The lens is then best removed and reinserted with fresh insertion fluid.

Red eyes and/or dry eyes:
Scleral lenses fit the sclera. The sclera is covered by a mucous membrane (the conjunctiva). The conjunctiva is full of mast cells. The histamine in the mast cells is released by friction. The pressure of a scleral lens can irritate the already sensitive conjunctiva, causing an allergic reaction, especially during the hay fever period. In addition, the lens material of scleral lenses is highly oxygen permeable. This makes the lens material sensitive to protein deposits. Proteins that precipitate on the lens material change their structure and start to behave like an allergen. The eye then gets an allergic reaction due to the protein deposit. Sometimes scleral lenses are only tolerated with supportive eye drops prescribed by the ophthalmologist. Antihistamine eye drops can greatly improve the tolerance of scleral lenses.

Burden of contact lens solutions:
The use of scleral lenses includes contact lens solutions without preservatives. Even though there are no preservatives in the liquid, a liquid can still irritate the eye. For example, the pH of the liquid can also differ greatly from your own tear. Slight burning that lasts for the first 10 minutes is an indication of a fluid problem.

Burden of cosmetics:
All creams and make-up used on the face can get into the eye, even if you use it far from the eye. Cosmetics are often greasy in composition. If cosmetics get on a scleral lens, it is difficult to get off. A greasy lens causes blurry vision. The lens plunger with which the lens is inserted regularly appears to give a greasy imprint. So make sure you work cleanly.

Not seeing clearly:
Scleral lenses create a new, smooth front for the deformed keratoconus cornea. All keratoconus contact lenses work based on this principle. You would think that the eye should be able to see perfectly again with a scleral lens, but nothing could be further from the truth. A scleral lens only corrects the shape error of the front of the keratoconus. Keratoconus is also on the inside of the cornea. Because this error is not corrected, shadows appear on the top of letters instead of shadows on the bottom of letters. Fortunately, the shadows with a scleral lens are much smaller than the shadows without lens correction. These uncorrected eye errors are also called higher order aberrations. As a result, you notice that you can’t see clearly, especially in the evening.

Fewer problems with scleral lenses

Over the years, problems with scleral lenses have reduced significantly. A lot has been technically improved. The lenses have become much thinner and modern lens materials more permeable to oxygen. The knowledge about fitting the lenses has also improved enormously, as has the availability of better scleral lens fits. The advent of smaller scleral lenses has removed many of the problems from large scleral lenses. The finish of scleral lenses has also improved. Lathes can turn all kinds of complicated shapes much more precisely. With the advent of scleral lenses with wave font correction (Conepower technology), problems with shadows can be better corrected.