If you have been informed that you cannot wear regular contact lenses because of an irregular cornea or some ocular surface disease like dry eyes or Keratoconus, you may consider asking your eye doctor about scleral contact lenses. These are one type of contact lenses for Keratoconus. Another is Rose K Lenses.
These lenses are of a large diameter, made of gas permeable material and are rigid material contact lenses. These are specially designed to fit over the entire cornea and rest on the white part of the eye known as the sclera. These lenses manage corneal irregularities like Keratoconus and ocular surface abnormalities. They do this by acting as a fluid reservoir and in addition providing comfort for people with severe dry eyes who otherwise could not tolerate regular soft lenses. Thus, scleral lenses functionally replace the irregular cornea with a perfectly smooth optical surface which improves overall visual acuity. These are highly oxygen permeable lenses and thus are indicated in severely affected corneas.
Scleral contact lenses are noticeably larger than standard gas permeable contacts with the smallest diameter available being approximately 14.5 mm, and the largest can be up to 25 mm. The size of the lens used is often chosen based on the degree of complexity of the condition. (image comparison)
According to their fitting and size, there are 4 types:
1. Corneo-Scleral Lenses
2. Semi-Scleral Lens
3. Mini-Scleral Lens
4. Full Scleral Lens
During your scleral lens fitting consultation, your eye care professional or scleral lens specialist will determine the best scleral lens type and size using various diagnostic lenses which will be for your specific condition, needs and parameters.
Scleral Lenses are also prescribed for corneal conditions like irregular astigmatism, irregular cornea patients, post corneal transplant, vision correction, post corneal grafts, corneal abrasions, and dry eye disease, and many more. All of these conditions are responsible for less or poor vision. These sight-threatening conditions reduce the quality of life. These require large-diameter gas permeable contact lenses also known as speciality lenses for masking corneal disease.
Optometrists and ophthalmologists recommend scleral contact lenses for a variety of challenging eye conditions, one of the most common being keratoconus.
Keratoconus is classified into Mild, Moderate or Severe Keratoconus. When it has reached a stage where these scleral lenses also become a challenge it is known as Advanced Keratoconus. This then requires a complete custom lens design option.
In cases of early keratoconus, where the eye power is still not very high, a standard gas permeable lens can be an option. However, sometimes the lens does not centre properly on the eye or moves excessively with blinks and causing discomfort. Thus switching to a large-diameter scleral contact lens may solve the problem and give stable vision.
Because the design of scleral lenses is to vault the corneal surface and create a corneal clearance as well as limbal clearance and directly rest on the sclera, these lenses often are more comfortable for a person with keratoconus.
Scleral contact lenses are a good option for eyes that have undergone a cornea transplant. People with severe dry eyes that might need a large tear reservoir often get fitted with larger scleral lenses, as they have more capacity to hold fluid or bridge large changes in corneal curvature. Severe dry eyes are caused by conditions such as Sjogren’s syndrome, graft-versus-host disease (GVHD), and Stevens-Johnson syndrome.
Scleral lenses not only give sharper vision but also comfortable vision with improved quality throughout the day wear.
Scleral lenses are a type of speciality contact lenses that are custom-made to the exact specifications prescribed by your eye doctor after they perform all the tests and fitting, to provide the best possible vision, eye health, and comfort. Also, there is a wide range of scleral lens designs and contact lens materials available which your eye specialist can offer you according to your ocular health and requirements.
For these reasons, professional and fitting fees associated with scleral lens fitting and
lens replacement costs are higher than other contact lenses and vary with different
brands. Generally, the process of acquiring a scleral contact lens is as follows:
Step 1: Visit the eye hospital for a comprehensive eye test; testing your eye number,
general eye health, reviewing the diagnosis and retinal evaluation. In case you are
diagnosed with keratoconus, your eye doctor might ask you to undergo a topography
test where we come to know, how severe is the keratoconus and the reports also help
us decide on the scleral contact lens parameters to consider for your eyes.
Step 2: Before the scleral contact lenses are given, there is a scleral contact lens fitting
process, where a trial scleral lens is fitted on the eye to understand how it behaves in
your eye and note down some crucial measurements. Usually, the trial visit is for 1-2
hours because scleral contact lens fitting is different from other keratoconus lenses.
Step 3: Once the trial is finalized, we send the lens parameters along with the power of
the lens to the lab for the lenses to be made and after a few weeks the lenses arrive.
This is when you will be called up for the “Dispensing visit”. The newly arrived lenses
are fitted on your eye and verified if the lenses are made as per the eye doctor’s
instructions. On this visit, you will be taught the insertion and removal techniques of the
scleral contact lenses and also counselled and trained regarding the care and
maintenance procedures.
Step 4: Follow-up visits: Since scleral contact lenses require this rigour to finalize the fit,
the process of wearing and maintaining them is quite overwhelming sometimes, thus, a
follow up after 7 days of wear, 2 weeks after wear, a month after wear and every 6
months thereafter are required to make sure the lenses and your eyes are doing fine.
Most patients get comfortable with scleral contact lenses within the first week of wear.
The cost of scleral lenses can be quite high compared to other keratoconus contact
lenses and can range from Rs 75000 for both eyes to Rs 200000 for both eyes.
Sclera contacts are speciality lenses that are custom-made and fitted to each individual. They are designed to vault over the cornea and rest on the sclera, leaving room for fluid between the lens and the cornea. Scleral contacts are not dangerous, but there are some risk factors associated with their use.
We dont recommend that you sleep in your scleral contact lenses. Sleeping in your scleral lenses can cause the tear layer behind the lens to become stagnant, increasing the risk of eye infections.
Many patients who wear scleral lenses are able to wear them for 12-14 hours daily. Some patients may need to remove the lenses, clean them, and reapply them with fresh saline periodically throughout the course of the day in order to maintain the best possible vision and comfort.
Contact lenses have been successfully used for decades. They have even been shown to reduce the need for transplant surgery in people who suffer from significant keratoconus.
One of the biggest drawbacks of scleral contacts can be their cost. These lenses are custom fitted, which means that it takes a trained professional, or eyecare practitioner more time and effort to get them right. Each lens is individually crafted, which can drive up the cost. In the long run, however, scleral lenses are generally not drastically more expensive than other speciality contact lenses.
Complications are relatively rare. Possible hazards of sclera lens wear can include:
Most of the potential dangers of scleral contact lens use are related to user error or a poor lens fit.
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