What is a scleral lens and why does it work so well with many ocular conditions?
A scleral lens is a large diameter lens made of a highly oxygen permeable material. It does not move on the eye. It is not a contact lens in the strict sense of the word as it has no contact with the cornea. Instead, a liquid reservoir of sterile saline solution fills the space between the back surface of the lens and the front surface of the cornea. This liquid reservoir fills in the surface irregularities of the cornea allowing vision to be restored in a comfortable manner. The lens and the fluid liquid bandage beneath it protect the cornea from exposure to the environment and the rubbing effects of blinking. This cushion of fluid beneath the lens also provides oxygen to the cornea allowing the eye to heal. The effect is to create a smooth optical surface over the diseased or compromised cornea that replaces the distorted surface. Almost all of the time, vision and comfort are improved dramatically.
How large are the scleral lenses that you use and do the lens diameters vary according to the different eye conditions?
The lens diameters used do vary according to the diameter of the cornea, and the type of ocular condition that we are treating. For example, low degrees of keratoconus can be treated with a scleral lens of about 15 mm in diameter. Some eyes that have undergo corneal transplant surgery may require a lens of 20 mm in diameter. Every eye is different and must be treated as a stand alone project.
What eye conditions are best treated with a scleral lens?
There are a number of eye diseases and conditions that are best treated with a scleral lens. What must be appreciated is the fact that a scleral lens, when fit correctly is a medical device and a therapeutic device all in one. The lenses that we design can be fit to virtually any eye shape and for any degree of visual error while at the same time allowing the diseased or injured eye to heal. Common conditions include, but are not limited to:
- Pellucid Marginal Degeneration
- Post-refractive surgical complications due to LASIK, Radial Keratotomy (R-K) surgery, PRK, ALK, CK, and so on. Many of these complications include distorted and fluctuating vision, halos, light sensitivity, reduced vision at night and indoors, glare, halos, starbursting, ocular pain, chronic dry eyes and so on.
- Complications resulting from corneal transplant surgery such as irregular, distorted corneas, chronic dry eye and unstable vision.
- Post-LASIK corneal ectasia. At one time it was thought that corneal ectasia was a rare risk factor for LASIK. In reality, we are seeing more and more patients suffering vision loss due to post-LASIK ectasia and other side effects from LASIK years after the surgery was done.
- Chronic dry eye due to systemic disease, medications and a variety of ocular conditions.
- A variety of corneal and ocular conditions such as Stevens-Johnson Syndrome, Sjogren’s Syndrome, corneas damaged as a result of ocular trauma, corneal degenerations and dystrophies, chemical and burn injuries to the eye, and adjacent ocular structures, eyelid abnormalities, aniridia and many other diseases and conditions.
I have visual distortions because of dry eye. Can a scleral lens help me?
A gas permeable scleral lens replaces the cornea as an optical surface. It does not matter how distorted your corneas are. A well fitted scleral lens gives you the equivalent of a new cornea. As far as dryness issues area concerned, the bowl of the scleral lens is filled with unpreserved saline solution. When placed on your eye, the lens does not touch your cornea. A liquid reservoir of pure saline solution fills the space between the back surface of the lens and the front surface of the cornea. In other words, your corneas are always in a moist environment.
My present lenses hurt and very often pop out of my eye. Will this happen with scleral lenses?
No. When properly fit scleral lenses will not dislodge or pop out of your eyes. This is because the lenses are large and come to rest on the white portion of the eye. The lenses do not move on the eye and the edges fit under the eyelids. Because of this, the lenses are very stable, and extremely comfortable. With almost all of our patients, the comfort of our custom made scleral lenses is comparable to that of a soft lens. In many cases, patients’ comfort with their scleral lenses exceeds the comfort that they experienced with their prior soft lenses.
Are there different types of scleral lenses and if so what is different or unique about the scleral lenses that you design? What is involved in obtaining the optimal lens fit?
There are less than a dozen laboratories in the world capable of making a gas permeable scleral lens. The scleral lenses made by each of these laboratories differ from each other in one way or another. Our unique scleral lenses are made using proprietary software developed by Zeiss optical. These lenses can replace the need for corneal transplant surgery which has the potential for serious complications, a long healing period and an uncertain visual outcome.
What kind of instruments to you have to help with the fitting process?
It is important to understand that each lens is custom made for each individual eye. Therefore the ability of the doctor to fit these lenses demands greater experience and more time than fitting conventional rigid gas permeable lenses or soft lenses. The following are just a few of the technologies that we use to help us design a one of a kind lens for a particular eye:
- Computerized Corneal Topography. This technology provides us with a 3-dimensional map of the entire corneal surface. Thousands of reference points are measured which provides us with the curvatures, elevations and depressions along the corneal surface. The 3-dimensional model provided helps us to design the appropriate scleral lens for that specific eye.
- Zeiss Visante OCT (Optical Coherence Tomography). This instrument is the first and only instrument designed to measure and analyze the entire front portion of the eye in cross section. Anterior ocular structures and irregularities can be measured in great detail. The structures that can be measured include the entire cornea from the back surface onto the front surface. Most important, when fitting a scleral lens, it is critical to know the clearance between the back surface of the lens and the front surface of the cornea.
- Ocular Coherence Tomography allows us to measure this clearance to within 4 microns.
Are scleral lenses difficult to insert and remove?
No. However, one has to be taught. It usually takes a 30 minute session to teach a new patient how to insert and remove a lens. Like anything else, there is a learning curve. Almost all of our patients manage this within a very short period of time.
What can I expect to take place on my initial visit to the Global Vision Rehabilitation Center?
Your initial visit will include the following:
- 1. A careful and comprehensive health history including your ocular and vision history.
- 2. A comprehensive eye health examination involving both the anterior and posterior ocular tissues (the cornea, retina, optic nerves etc.) A number of instruments will be used to image all of these ocular structures.
- 3. A careful examination of the eyelids and ocular glands responsible for maintaining a healthy pre-corneal tear film. In addition, a careful dry eye evaluation will be done.
- 4. Corneal topography will be done on both eyes. This technology is essential for measuring the curvatures of the front surface of the eye (the cornea). The information provided is invaluable in helping us design the proper scleral lenses needed for your eyes.
- 5. Optical Coherence Tomography (OCT): This technology allows us to evaluate the integrity of the cornea and also to examine the relationship of the scleral lens on the cornea. With OCT, we can measure the clearance (to within 4 microns) between the back surface of the scleral lens and the front surface of the cornea. OCT allows us to obtain a level of precision in scleral lens fitting not possible until now.
Your scleral lenses will be ordered at the end of the initial visit. New lenses almost always arrive within 48 hours. Very often, we can obtain scleral lenses the next working day. Please understand that the procedures described above will be repeated during follow-up visits to make sure that all of the ocular structures are maintaining their integrity and that no changes are taking place as far the the scleral lens-cornea relationship is concerned.
How Long Can I Expect My Scleral Lenses To Last?
In our patient population, 3 years appears to be the average life expectancy of the scleral lenses that we design. However,we have many patients who are wearing the same lenses for over 6 years. We recently introduced new cleaning solutions which are now able to keep the optical surfaces of our lenses smooth, clear and pristine for many years. We expect our lenses to last longer since the introduction of these new cleaning solutions.
Dr. Boshnick, Why Are You So Passionate About Scleral Lenses?
For over 20 years, I have been intimately involved with the design and manufacture of scleral lenses. Our newest design lenses have been so effective in treating the many vision disorders of our "hi need" patient population that we named the lens after our practice: "The Global Vision Rehabilitation Center" hence The GVR Lens.
In North America, there are millions of patients that have ocular conditions that cannot be properly addressed with eyeglasses or conventional contact lenses. It is only the scleral lens made from a highly oxygen permeable polymer that has the ability to dramatically restore quality vision to this "hi need" population.
It is my strong belief that the quality of our life is related to the quality of our vision. If one has lost vision due to keratoconus, LASIK, ocular trauma etc., then all other aspects of that patient's life is also negatively impacted. There is no greater reward for me than to play a part in the restoration of a patient's vision. That is what our practice is all about and it is also what I am all about, professionally.
I am currently wearing hybrid contact lenses which are providing me with clear vision but start hurting after 30 minutes to an hour of wear. My doctor is not able to improve my comfort with the hybrid lenses. Why is this happening and can your scleral lens design give me both comfort and good vision?
Hybrid contact lenses have proven to be a very effective lens technology for the treatment of keratoconus and other corneal diseases and conditions. There is no one lens technology that will address all of the vision and comfort issues of every ocular condition that every patient faces. While hybrid lenses can be very effective in providing good vision and comfort to many patients with compromised corneas, they will not work well with severely compromised corneas. Hybrid lenses are designed with a gas permeable central portion that is bonded to a soft peripheral skirt. While the lenses drape over the entire cornea, the rigid portion of the hybrid lens is too small to vault over the entire cornea. With many irregular corneas, the rigid portion of the hybrid lens may tend to "dig" into the compromised cornea. If this cannot be corrected with a change in the hybrid lens design, it may be necessary to place on this particular eye a soft disposable lens prior to inserting the hybrid lens.
If this "piggy-back" approach does not provide the necessary comfort, then the only other option will be a scleral lens. A scleral lens will vault over the entire cornea. No portion of the compromised cornea will be touched by the scleral lens. The space between the back surface of the scleral lens and the front surface of the cornea is filled with pure, unpreserved saline solution. In other words, your corneas are always in a wet environment. The white portion of the eye (the sclera) supports the scleral lens. Comfort and vision is almost always excellent. In addition, these lenses cannot become accidentally dislodged or pop out of your eye due to a sudden eye movement.
Since The Scleral Lens Is Larger Than A Regular Gas Permeable Lens, Why Are They More Comfortable? It Seems Logical That A Larger Lens Will Be More Uncomfortable Than A Smaller Lens.
Almost all of the corneas that we see in our office have highly irregular curvatures and surfaces. Many of these corneas are dry and irritated due to an underlying condition or disease process such as keratoconus or post-LASIK complications. When a small gas permeable lens is placed on this type of corneal surface, the normal movements of the eye and the blinking activity of the eyelids will cause these lenses to move and rub against this irregular corneal surface. Because a scleral lens vaults over the cornea and rests on the white portion of the eye (the sclera) these is no lens movement. In addition, the edges of the scleral lens fits under the eyelids. Patients who blink while wearing a scleral lens do not feel the lens because the edge of the lens is tucked under the eyelids and no lens movement takes place with normal eye movements or blinking. In addition, a reservoir of pure saline solution exists between the back surface of the lens and the front surface of the cornea. This means that the eye is always in a liquid environment. These comments do not apply to the smaller gas permeable lenses.
How long can I expect my scleral lenses to last?
On average, you can expect your lenses to last 3 or more years. Of course, a great deal depends on how you take care of them. Like anything else about our bodies, our eyes and our prescriptions can change. Over the years nothing stays the same. This is also true for our eyes. This is the reason that an annual comprehensive eye, vision and scleral lens fitting evaluation be done each and every year. It is also very important to contact our office if you should notice any change in your vision or ocular comfort.
What solution do I fill my scleral lenses with?
It is important to use .9% sterile, unpreserved and unbuffered saline solution. We will provide you with a supply of this solution which we always keep on hand in the office. You will also be able to purchase this solution on line from the manufacturer. Any preserved solution placed into the bowl of the lens has the potential to cause eye irritation, inflammation or infection. If you are unsure what to use or if you should be in a city or country where this solution is unavailable, please contact our office. Either my staff or I will be happy to help you.
What kinds of solutions will I need for scleral lenses?
There are 3 main solutions that are used for scleral lens wear:
- When removing your scleral lenses, you will need to use a good cleaning solution. This is basically a special soap in solution form that is rubbed onto the front and back surfaces of the scleral lens. Oils, mucous and other secretions can adhere to these lens surfaces. It is important that they be removed at the end of each wearing day.
- When placing your scleral lenses in the lens case, we recommend that you fill the case with a special soaking and disinfecting solution. The lenses stay in this solution overnight and the solution is discarded from the lens case every day.
- When inserting your scleral lenses onto your eyes, the lens “bowl” is filled with .9% unpreserved saline solution to the very top of the lens concavity. In addition, this solution is used for rinsing the cleaning solution off of the lenses and for rinsing out the lens case.
We recommend using a scleral lens protein remover every 2 weeks to keep your lenses debris free and to give you the “brand new” lens feeling. The name of this solution is “Progent” and can be obtained from our office or online from the manufacturer.
We provide all of the above solutions to our patients at the lens dispensing visit.
Are There Any Complications Associated With Scleral Lenses?
Like any foreign object placed on our bodies, certain rules and protocols need to be followed in the use of scleral lenses. These are:
- To reduce the risk of eye irritations and infections, scleral lenses must be cleaned with a special cleaning solution after they are worn at the end of the day. Our office provides our patients with this lens cleaner.
- A special unpreserved sterile saline solution must be used when inserting scleral lenses. This saline solution is used to fill the bowl of the lens upon insertion. Using tap water or a preserved solution can create complications including infection. We provide this preservative saline solution to all of our scleral lens patients.
- We recommend that a protein removing solution be used on the lenses once each month. The ocular secretions that we all produce are protein in nature. Over time these proteins can adhere to the lens surfaces and can create eye irritations and reduced vision. Our office provides our patients with this protein remover.
- Hygiene is extremely important when working with scleral lenses. We recommend that our female patients apply their makeup after inserting their scleral lenses. The scleral lens case should be replaced on a monthly basis and cleaned daily. In addition, the lens conditioning solution placed in the case with the scleral lenses should be replaced daily. Of course, patients must wash their hands thoroughly prior to inserting and removing their scleral lenses.
- Scleral lenses do not move over the compromised cornea. Instead, these unique lenses vault over the cornea and are supported by the white portion of the eye, known as the sclera. The space between the back surface of the lens and the front surface of the cornea is filled with sterile saline solution.
- Patient suffering loss of ocular comfort due to keratoconus, post-LASIK complications and other ocular conditions and diseases, have severely compromised corneal surfaces. Corneal RGP lenses rest on top of this cornea cornea and move over the irritated corneas with each blink of the eyelids. This lens movement can create additional damage to these irritated corneas.
- Because the scleral lenses fit under the eyelids, there is no lid awareness when blinking as the eyelids pass over the smooth surface of the scleral lens.
- Because so many of these eyes are very dry and irritated, corneal lenses can make this condition worse. The space between the back surface of the scleral lens and the front surface of the cornea is filled with unpreserved saline solution. Because of this, dry, irritated corneas are always in a wet environment.
- Post-Refractive surgical complications (post-refractive ectasia)
- Corneal scarring
- Irregular astigmatism
- Damage to the cornea due to trauma
- Keratoconjunctivitis sicca (chronic dry eyes)
- Recurrent Corneal Erosion
- Corneal Dystrophies
- Corneal Degenerations
- Numerous viral, bacterial, fungal and parasitic infections
- Post-Corneal transplant eyes
If the above protocols are followed, the risk of ocular complications are extremely small. The patients who I have provided scleral lenses to are “high need” patients. That is, this population has lost vision and ocular comfort due to refractive eye surgeries such as LASIK, Radial Keratotomy, PRK, keratoconus, corneal transplant surgery and so on. Most of this patient population have very dry eyes and a compromised ocular surface. The scleral lenses that we design for our patients protect the compromised cornea from the environment and from the blinking action of the eyelids. In addition, because the corneas are always in a liquid environment, these unique lenses act as a therapeutic device.
How Do Scleral Lenses Differ From Corneal Lenses?
Corneal or conventional gas permeable lenses are designed to fit on the corneal surface and parallel the ocular surface of the cornea. A gas permeable scleral lens vaults over the cornea and is supported by the white portion (the sclera) of the eye. A properly fit scleral lens will not touch the cornea unlike a corneal lens. With a scleral lens, the space between the back surface of the lens and the front surface of the cornea is filled with sterile, unpreserved saline solution. In other words, the irritated, compromised cornea is always in a liquid environment. A corneal lens can rub against a compromised cornea and have a traumatic effect on the delicate tissue.
There are many corneal and ocular conditions that prevent patients from seeing the world clearly. Many patients with these conditions cannot be made to see clearly with eyeglasses or conventional contact lenses. These conditions include, keratoconus, autoimmune disease, eyes with corneal transplants and eyes that have undergone refractive surgical procedures such as LASIK and Radial Keratotomy. Scleral lenses can allow almost all of these patients to see clearly and comfortably once again. Indeed, a scleral lens is the only technology that will allow almost all of these patients to see clearly and comfortably once again while at the same time protecting the compromised cornea and allowing a healing action to take place.
Why Are Scleral Lenses More Comfortable Than RGP Corneal Lenses?
There are a number of reasons for this including:
I’ve had difficulty removing my RGP lenses. Will I have a problem removing a scleral lens?
No. I have fit several thousand patients over the years with scleral lenses and I cannot recall a single instance where removal of these lenses has ever been a problem. A small device that is placed onto the lens gently removes the lens from the eye. Also, unlike conventional RGP lenses, scleral lenses will never pop out of the eye.
I have small eyes. Will I have a problem with inserting and removing scleral lenses?
We have fit patients will all types of eyes without incident. All of our scleral lenses are designed for each individual eye. You will not have any difficulties with inserting and removing your scleral lenses. We allow a great deal of time in not only fitting these unique lenses but also instructing our patients on the proper insertion and removal techniques.
How many hours a day can I wear my scleral lenses? Can I sleep with them?
The great majority of our patients wear their lenses all day. That is from the time they wake up and until they prepare to go to sleep. If by sleep you mean sleeping with the lenses all night, then the answer is no. However, many of our patients nap with their scleral lenses during the day and have had no issues doing this.
How long do I need to stay in Miami if I visit your office, and where do I stay? My vision is very bad. Can someone transport me from the hotel to your office if necessary?
I request that my patients visiting my practice from distant locations remain in Miami for at least one week if possible. There are several hotels near my office that provide shuttle service to not just my office but to other locations in Miami. In addition, we have a private driver who can be available to you on any day and at any time. I prefer to see my patients on their initial visit very early at around 8:00 AM. Our laboratory can make your lenses on the same day you are seen for delivery to my office the very next morning.
What does “RGP” mean and why is it important? Are scleral lenses also RGP lenses?
“RGP” stands for “ Rigid Gas Permeable”. “RGP” lenses are small lenses that rest on the cornea and in many cases cannot be tolerated by irritated, compromised corneas. Scleral lenses are also made from gas permeable materials. What this means is that oxygen from the tear film and the atmosphere can enter the cornea right through the lens material. Prior to the development of “RGP” materials, the only lens material available was made from a material known as “PMMA”. Lenses made from this material do not allow any oxygen to pass through it. “RGP” materials are important because these materials provide a significant health benefit to especially compromised corneas.
Is it OK to rinse my scleral lenses with tap water before I insert them?
No. Scleral lenses should be rinsed with sterile unpreserved saline solution before insertion. The quality and ingredients of tap water differ from location to location.
What is the difference between a scleral lens and a sclera lens?
A sclera lens is a novelty lens, like colored contacts or 'Halloween lenses'. A scleral lens is supported by the white portion of the eye known as the sclera. Scleral lenses vault over the cornea and come to rest on the sclera. The space between the back surface of the scleral lens and the front surface of the cornea is filled with saline solution. In other words, the cornea is always in a moist environment.
I have a lot of astigmatism. Can scleral lenses help me? If so, do the lenses need to be weighted so that they don’t rotate?
Almost all cases of astigmatism are due to an irregular cornea. Almost always, scleral lenses will neutralize this corneal irregularity so that an astigmatic correction will not need to be incorporated into the lens design. However, occasionally some of the astigmatism cannot be corrected with a spherical scleral lens correction. In cases like this, an astigmatic design is created with the scleral lens weighted so that it will not rotate. This lens does not need to be inserted in any special manner as the lens will rotate to the proper orientation on its own.
Can scleral lenses be made just for reading? I think that I may prefer to wear glasses for distance with the reading scleral lenses on.
Of course. Scleral lenses can be made with virtually any prescription. We can make the scleral lens prescription for computer distance or reading. Scleral lenses can also be made in a multifocal design.
Is it sometimes necessary to wear glasses over the scleral lenses to achieve sharpest vision?
Yes. Two vision situations come to mind: First, patients over the age of 40 will encounter difficulty with their near vision. With this patient population we will offer several options to help with their vision issues. One option is to wear reading glasses over their scleral lenses. Another option is to alter the power of one lens so that one eye is mainly in focus for close up and the other eye is in focus for distance. Everyone is different and I will customize the lens prescription for each patient’s specific visual needs. Second, rarely after the scleral lens fitting is completed, we encounter an optical phenomenon known as residual astigmatism. Most of the time, this astigmatic error can be corrected with our scleral lens design. Occasionally it cannot. If this happens we can incorporate the residual astigmatic correction into the scleral lens.
I fear that I will not be able to insert my scleral lenses. Is there anything that can help me with inserting the scleral lenses?
Like anything else that we have never tried, there will always be a fear of the unknown. If you never rode a bicycle it will naturally create fear of falling off the bike. With proper instruction, virtually everyone gets to ride their bike without falling. This is the same with scleral lenses. We teach our patients the proper way (for that particular patient) to insert and remove their lenses. Some of our patients have physical disabilities. For these patients we use a special instrument that will allow these patients to insert their lenses without the use of their hands. We have scleral lens patients varying in age from 5 to 85. All are able to insert and remove their lenses. We will spend whatever time is needed to teach you how to do this.
What is meant by “corneal blindness” and what can be done about it?
Corneal blindness refers to a host of corneal diseases and conditions that can make an eye legally blind. First we need to appreciate that the cornea is in many ways a separate organ that covers the front of the eye. The cornea has its own metabolism and for the most part is separate from the rest of the eyeball. Small alterations on the surface of the cornea can have profound effects on visual acuity. In addition, small internal structural changes within the cornea may result in vision loss due to decreased transparency. Some of the conditions affecting the cornea that can lead to “corneal blindness” include:
Patients with most of the non-infectious conditions listed above can have their vision restored with the use of gas permeable scleral lenses. A careful comprehensive eye and vision examination needs to be done to make sure that the internal ocular structures such as the optic nerve and macula are healthy. If this is so, scleral lenses are the best option for this patient population to regain quality vision once again.