Contact lenses remain one of the most popular methods of correcting refractive eye errors that mean that the patient needs prescription lenses to see clearly. Unlike those which are placed in glasses frames, contact lenses are worn directly on the surface of the eyes, eliminating many of the inconveniences of wearing glasses. Unless you are a contact lens wearer already, chances are that you might not realize that there are actually a variety of different contact lenses to choose from to ensure that patients get the right type based on their individual requirements. However, the standard type of contact lens which makes complete contact with the surface of the eyes across the whole of the lens is not necessarily suitable for every patient. As such, there are also a number of specialty contact lenses that are designed specifically so that patients who cannot wear standard contacts can still benefit from this style of solution. Scleral lenses are one type of specialty contact lens.
Scleral contact lenses are large-diameter contact lenses that do not make contact with the entire surface of the eye but instead vault over the majority of it, only touching down on the sclera, which is the white part of the eye. The gap that is beneath plays an important role in the suitability of these lenses for those patients who can’t wear regular varieties. There are several sizes of scleral lenses:
Semi scleral: the smallest variety although they are still larger than standard contacts, they rest on the line where the cornea meets the sclera.
Mini scleral: slightly larger than semi-scleral lenses, these touch down on the surface of the eye at the anterior of the sclera.
Full scleral: these have the largest diameter and also the greatest amount of clearance in terms of the vault over the cornea.
Scleral lenses are designed to have some clearance between the surface of the cornea and the back of the lens itself. They are designed this way in order to accommodate some corneal abnormalities and other conditions that can prevent a patient from wearing normal, full-contact contact lenses. They are also made from special, gas-permeable material which also helps to make them a preferred option for certain patients. This unique design element of scleral lenses means that wearers can experience the following benefits:
More oxygen reaching the eyes whilst wearing them
Tear film becomes trapped in the gap, which acts as a reservoir for it and helps to keep the eyes moist and comfortable
There is space for any bulges in the cornea
The larger diameter of the lenses helps keep them stable on the eyes
Their larger size also makes it easier for them to be handled
Scleral lenses can be particularly beneficial for those patients who have conditions that make regular contact lenses unsuitable. These include those who have the following issues:
Many corneas have a fairly even, dome-shape that fits snugly into the shape of regular contact lenses. However, some patients have corneas that are far steeper or that have bulges, such as is the case with keratoconus which is a condition characterized by the thinning and bulging of the cornea. Such issues mean that regular lenses do not fit properly. However, scleral lenses have sufficient space beneath the vaulted section to accommodate most corneal abnormalities, making them an ideal solution for patients who fall into this category.
Dry eyes are both a symptom and the name of an actual eye condition that occurs when there is a problem with the distribution of tear film over the eyes. Contact lenses float on the lubrication present on the surface of the eye, but if a patient has dry eyes, it may be difficult or impossible to wear regular contacts. However, scleral lenses enable tear film to be trapped on the surface of the eye for longer, in the fluid reservoir that is created by the gap between the cornea and the lens. This increased lubrication makes these lenses able to be worn by patients who have dry eyes. Similarly, the gas permeable nature of scleral lenses allows more oxygen to reach the eyes, preventing them from drying out as quickly as they might with regular lenses.
There are some ocular diseases that affect the surface of the eyes and make it difficult for patients to wear normal contact lenses. Fortunately, scleral contacts create a barrier that protected the compromised anterior ocular surface from exposure, making it possible for those patients with ocular surface diseases to still wear contacts instead of glasses.
If you would like more information about scleral lenses and who might benefit from them, get in touch with our experienced and knowledgeable eye care team in El Paso, TX who would love to help you.