Many people are surprised to learn that there are multiple types of contact lenses to choose from. One of these is a type of speciality contact lens called scleral lenses. Speciality contact lenses are a category of contacts which vary from the traditional design in some way – usually to accommodate some ocular abnormality or health condition.
Scleral lenses are a form of speciality contact lens that has several differences when compared to the conventional style. Let’s take a look at these differences in more detail.
Although traditional contact lenses can vary in size, they are typically between 9mm and 15mm in diameter. Scleral contact lenses are much bigger by comparison. In fact, their name comes from the fact that they rest on the sclera, which is the white part of the eye. Scleral lenses range from 14.5mm to 24mm, which enables them to cover the entire corneal surface.
Scleral lenses tend to be divided into three types based on their size. These are known as:
Semi-scleral lenses, which are the smallest variety, and their edge sits on the spot where the cornea meets the sclera
Mini scleral lenses, which are slightly bigger and their edge rests on the anterior sclera
Full scleral lenses, which are the largest and extend out onto the outer sclera
Scleral lenses have a uniquely vaulted design which means that they don’t make contact with the entire surface of the cornea like normal contact lenses do. Instead, they are shaped with a vaulted section that creates a space between the back of the scleral lens and the front surface of the eyes. This space accommodates any corneal abnormalities such as bulges (characteristic of keratoconus) and scratches and abrasions. It also traps tear film, acting as a fluid reservoir that keeps eyes moist and hydrated.
Most regular contact lenses aren’t made from gas permeable material, but scleral lenses are. Gas permeable contact lenses enable oxygen to flow through them and reach the cornea surface. This is important because the eyes don’t get enough oxygen to be healthy through our usual circulation alone and instead, they rely on their surface being exposed to the air. When the cornea doesn’t get enough oxygen it is known as hypoxia, and over time it can have severe consequences for your eye health and vision.
Scleral lenses can be successfully used by many people, but they are a particularly good choice for people with specific eye conditions. These include the following:
When your eyes don’t make enough good quality tear film, or the tear film you have drains too quickly, it is a condition known as dry eyes. Scleral lenses help keep the eyes moist, preventing dehydration and associated discomfort and other symptoms.
Corneal scratches can occur as a result of trauma, infection or even illness. They can make wearing regular contact lenses uncomfortable and even painful. However, scleral lenses mean that no pressure is placed on the cornea, and this makes them a comfortable and viable option for patients with corneal abrasions.
Keratoconus is caused by weakened fibers in the eyes that enable the cornea to thin and bulge outwards. It isn’t common but it does have a direct impact on your vision, meaning that prescription lenses are required so that you can see clearly. The bulging means that conventional contacts aren’t stable or uncomfortable, but scleral lenses provide a viable alternative.
If you would like more information about scleral lenses, or if you would like to schedule an appointment to see if you are a good candidate for them, please call Hedges Eye Care in Newberry, Florida at (352) 306-1103 today.