Corneal Disease, Rehabilitation and Specialty Lenses

Click Here for a related article published by Dr. Boshnick in Refractive Eyecare

The cornea is the eyes outermost layer. It is the clear dome-shaped surface that covers the front of the eye. Although the cornea is clear and seems to lack substance, it actually is a highly organized group of cells and proteins. Unlike other tissues in the body, the cornea contains no blood vessels to nourish or protect it against infection. Instead, the cornea receives its nourishment from the tears and aqueous humor that fills the chamber behind it. The cornea must remain transparent to refract light properly, and the presence of even the tiniest blood vessels can interfere with this process. To see well, all layers of the cornea must be free of any cloudy or opaque areas.

It is estimated that there are over 5 millions Americans who have lost quality vision due to ocular trauma and various corneal conditions. Some of the corneal conditions which have resulted in vision loss and ocular discomfort include: keratoconus, pellucid marginal degeneration, post-refractive surgeries such as lasik-induced ectasia, corneal ulcerations, severe dry eye, various corneal dystrophies, Stevens-Johnson Syndrome, shingles, ocular herpes and corneal transplant surgery.

Many of the above conditions have left patients with corneas so severely distorted, that eyeglasses or conventional soft or hard contact lenses are unable to restore quality vision and comfort. In addition to these corneal distortions, many patients have corneas that are so dry and/or traumatized that they are unable to open their eyes due to lights and other irritants.

At the present time, there are several contact lens manufacturers in North America, Europe and Australia working to introduce specialty lenses and materials to address many of the above conditions. In addition work is now being done utilizing stem cells to promote healing and restore healthy ocular tissue.

For many years, our office has been dedicated to this mission; that is to assist patients with many debilitating ocular conditions regain quality vision in a non-invasive manner. Our office has become the largest scleral lens practice in North America. Scleral lenses are specialty lenses that very often are therapeutic in nature. These are large gas permeable lenses that we use to restore health, vision and comfort to patients suffering from the above conditions. Scleral lenses vault over the cornea without touching it. The lenses are supported by the white portion of the eye (the sclera). A special fluid fills the space between the back portion of the lens and the front of the cornea. This liquid environment actually promotes corneal healing. Because of this, scleral lenses are medically necessary to treat the conditions mentioned above.

pseudomonas scar with scleral lens	scleral lens on advanced keratoconic cornea with Intacs
15mm gas permeable scleral lens on Stevens-Johnson Syndrome eye	18mm gas permeable scleral lens on transplanted cornea having undergone 2 separate radial keratotomy procedures

For those considering a corneal transplant please look at these photos and read the explanation below.

one week post-surgical transplant

Blind Eye Following Corneal Transplant resulting in internal ocular infection.

This patient had a corneal transplant several months ago. The top photo was taken about 1 week after the surgery. For unknown reasons this cornea was rejected. Another transplant was done about 1 month later. Shortly after the 2nd transplant infection took place within the eye (endophthalmitis). Due to the resultant debris created within the eye from this infection a vitrectomy was done (vitreous was removed and replaced with an inert solution). However, the infection and it's aftermath caused a retinal detachment. The intraocular pressure also dropped dramatically causing the iris tissue to be "sucked" into the globe obliterating the pupil. This is now a blind eye with no light perception and no possibility of regaining useful vision.

The purpose of these photos and e-mail is to explain that a corneal transplant is not a risk free procedure. Although what you see here is extremely rare, there is always the unforeseeable that may occur when any type of invasive eye surgery is undertaken.

This condition is called Phthisis Bulbi and often results in enucleation of the eye.