Occasionally I will be asked questions about scleral lens quality and about what is the best scleral lens. Many patients think about scleral lens technology like many of us think about cars or electronics. Most of us assume that a Mercedes Benz is a superior automobile compared to most other cars. This is not how it works when it comes to specialty contact lenses and specifically to scleral lenses.

Every eye is different and so is every patient. Not only that, every ocular condition comes with its own unique history. In addition to this, the shape and contour of every eye is different just like every face is different. Thankfully, today’s scleral lens technology allows us to create individualized scleral lens designs to better address the vision and comfort needs of every patient.

How Do You Determine The Best Scleral Lens Design For Each Patient?

When patient’s first come to visit our specialty lens practice, there are many things that we need to consider. These include the patient’s medical history, their visual acuity and comfort with their existing eyeglasses or contact lenses.

We also want to know what the patient’s goals are, what kind of work that they do, how they use their eyes. Before getting involved with any lenses, a careful eye health examination is done. Images and photos of all the ocular structures are taken and carefully documented.

Once we decide to fit a patient with a scleral lens, careful measurements are taken of the front surface of the eye. These include corneal topographies, and anterior segment OCT (optical coherence tomography) images. In addition a careful dry eye evaluation is done including images of the patient’s meibomian glands. These are the glands located within our eyelids and are responsible for keeping the ocular surface moist.

There are 3 methods that doctors use to design a scleral lens. These include:

1. Conventional scleral lenses that are designed using a diagnostic scleral lens fitting set.
2. Customized scan based technology using special imaging computers capable of measuring (virtually) every “hill and valley” of the ocular surface of the eye. The images taken are uploaded to a special lab that uses software compatible with our imaging computer to allow them to make a scleral lens with every aspect of the ocular surface embedded into the back surface of the scleral lens. In other words the scleral lens is designed to exactly fit the patient’s eye.
3. Impression based scleral lens technology. This technology involves taking an impression of the front surface of the eye. It is a pain free procedure that takes about 3 minutes to do. The impression taken is sent to a special lab where 3-D printing technology is used to make a scleral lens where every “defect” along the ocular surface is embedded onto the back surface of the scleral lens.

With the scleral lens technologies explained above, almost all of our “hi need” patient population are comfortably wearing scleral lenses created by the last 2 technologies explained above.

• Globally at least 2.2 billions people have vision impairment, and of these at least 1 billions people have a vision impairment that could have been prevented or is yet to be addressed
•  By 2050, 4.8 billions people (half of the world’s population) is projected to be nearsighted (myopic).
•  Cataracts are the main cause of blindness worldwide  and impact 100 million people at the present time.
• Diabetes is the leading cause of blindness in North America
• Globally more than 340 million people suffer from dry eye disease (DED). Meibomian Gland Dysfunction is the leading cause of dry eye disease affecting 86% of patients suffering from dry eye disease.

Corneal diseases and conditions are a leading cause of blindness worldwide. These diseases and conditions include keratoconus, refractive surgical complications, corneal ectasia, complications resulting from corneal transplant surgery, ocular trauma, corneal scarring, corneal dystrophies and degenerations (ie Stevens Johnson Syndrome), complications resulting from autoimmune disease (ie rheumatoid arthritis), ocular surface disease resulting from chemotherapy, complications resulting from ocular plastic surgery, incomplete eyelid closure due to neurological complications and ocular surface disease to prolonged use of many medications and treatments.

Many of the patients with conditions described above suffer from both poor vision and severe ocular pain. Many of these patients are unable to completely close their eyes and as a result cannot sleep throughout the night due to the necessity of using ocular lubricants frequently. Our specialty lens practice has the technology to design and fit highly customized oxygen permeable scleral lens shields to protect the delicate ocular surface tissues and keep these tissues moist during sleep. We design these scleral shields with the aid of computers using proprietary software. These scleral lenses or scleral lens shields that we design for patients with chronic dry eyes due to eyelid closure issues are different from the scleral lenses that we design for patients without these issues.

In general, 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 scleral lens and the front surface of the compromised cornea. The liquid reservoir fills in the surface irregularities of the cornea allowing vision to be restored in a comfortable manner. The scleral lens and the liquid reservoir beneath it protect the cornea from exposure to the environment and the rubbing effects of the eyelids when blinking. This cushon of fluid beneath the scleral lens also provides oxygen to the cornea allowing the eye to undergo a healing process. The effect is to create a smooth optical surface over the diseased or compromised cornea that replaces the distorted corneal surface. In all of the patients who we have treated, vision and comfort have improved dramatically due to the life changing abilities of scleral lenses.

A scleral lens is a large diameter lens made from an oxygen permeable polymer that is designed to vault over the front surface of the eye. A scleral lens is not considered a contact lens as there is no contact with the front surface of the eye, the cornea. Instead a scleral lens is designed to vault over the cornea and come to rest on the white portion of the eye, known as the sclera.

WHY A SCLERAL LENS AND NOT EYEGLASSES OR REGULAR CONTACT LENSES?

A scleral lens is intended to restore vision to patients who have lost quality vision and comfort due to ocular diseases, chronic dry eyes, ocular trauma and unanticipated ocular surgery complications. When treating an eye with a damaged cornea, eyeglasses will not provide functional vision. Almost all of the eyes that we see with damaged ocular surfaces cannot tolerate a conventional contact lens. This is because conventional contact lenses, both soft and rigid, rest on the corneal surface. While vision improvement may be achieved upon inserting these lenses, comfort readily decreases after a very short wearing time. In addition, conventional contact lenses can cause further damage to the highly compromised ocular surfaces of these eyes. We have to appreciate the fact that a preservative free saline reservoir exists between the back surface of the scleral lens and the front surface of the eye. This preservative from the liquid reservoir helps to provide nutrients to the cornea and allows a healing process to take effect. In other words, in addition to providing our patients with quality vision, we are helping the damaged ocular surfaces to heal.

WHAT ARE THE PRIMARY INDICATIONS FOR SCLERAL LENSES?

The primary indications for scleral lenses are corneal irregularities due to cornea diseases and conditions such as keratoconus, corneal ectasia, chronic dry eyes, complications resulting from refractive surgery such as LASIK, a variety of corneal degenerations and dystrophies, ocular trauma, corneal transplant surgeries and many other conditions. In effect, a well designed and fit scleral lens replaces the cornea as an optical surface. The resulting improvement in vision and comfort is almost always dramatic and can be very emotional for the patient. Over the years we have had many patients break down in tears upon receiving their scleral lenses and experiencing the dramatic improvement in vision.

I have been using scleral lenses for over 25 years to treat some of the most complicated and challenging ocular conditions. One example would be a patient who we treated who lost the upper eyelid of one eye due to flying glass from a car accident. Because he could not close this eye, the cornea soon began to degenerate due to prolonged exposure to the atmosphere. We fit this eye with a very thin, highly oxygen permeable scleral lens designed to both protect the ocular surface and to provide vision during a 12 month long eyelid reconstruction period where multiple eyelid surgeries were performed. There are also diseases and conditions of the inner lining of the eyelids that can create a painful eye. Many of these eyelids will scratch the cornea every time a patient blinks. The scleral lens will protect the ocular surface from the blinking action of these eyelids and also allow the ocular surface to heal.

HOW HAVE SCLERAL LENSES CHANGED THE WAY WE TREAT PATIENTS WITH OCULAR DISEASE?

Scleral lenses have dramatically changed the way we treat and manage patients who have lost vision due to corneal disease, surgery and ocular trauma. Scleral lenses have helped to reduce the need for surgical intervention and have significantly improved the quality of life for hundreds of thousands of patients especially those suffering from severe ocular surface such as Stevens-Johnson Syndrome, grafts host disease, neurotrophic keratitis, exposure keratitis and neuropathic pain. Because of the exciting and innovative improvements in scleral lens designs, the number of patients undergoing corneal transplant surgery in the United States has declined dramatically over the last 10 years.

WHAT ARE THE ADVANTAGES OF SCLERAL LENSES?

The main benefit of scleral lenses is that they can be designed to accommodate any degree of corneal steepness or shape. Scleral lenses provide better centration and stability than conventional contact lenses and they are more comfortable because the conjunctival tissue on which the scleral lenses rest is less sensitive (has fewer sensory nerves) than corneal tissue.

Furthermore, in patients who have experienced damage to corneal tissue, scleral lenses do not touch the cornea but rather bathe it continuously in preservative free saline so that scar formation is not encouraged and a healing process can take place.

ARE THERE DIFFERENT TYPES OF SCLERAL LENSES AND IF SO WHICH SCLERAL LENS IS BEST?

When our specialty practice introduced scleral lens technology to Florida in the early 1990’s, there was only one scleral lens design and only one scleral lens laboratory in the United States. Since then there has been an “explosion” of scleral lens materials and designs. It would be best to consider these different scleral lens designs as treatment options instead of pieces of plastic. Sophisticated computers using proprietary software are now used in both the manufacture of scleral lenses and in the designing and fitting of these lenses in the doctors’ office. Certain lens designs, materials, shapes and diameters may work well with one eye but not with the other eye. We have many patients using a scleral lens made by one laboratory on one eye and another scleral lens design made by a different laboratory on the other eye. It is definitely not one size and one design fits all.

WHY IS THERE SUCH A LARGE VARIATION IN THE COST OF SCLERAL LENSES?

What must be appreciated is that every patient is different and unique. Some ocular conditions are extremely complicated and may require a great deal of time to arrive at a successful conclusion. In addition, the laboratory costs of scleral lenses can vary widely due to materials and technology used in manufacturing these lenses. Therefore, the cost of the scleral lenses and the professional fees charged can vary for these reasons. What is most important is to find a doctor willing to spend whatever time is required to make sure that a successful outcome is achieved. Scleral lenses are a life changing technology that has positively affected the lives of hundreds of thousands of patients.