We are frequently asked to tell a doctor or a patient something of our method of fitting scleral shells. This is our attempt to do this in as brief and concise manner as possible.
A written referral (prescription for health reasons) from a doctor is required before we can proceed with the fitting.
Usually, two visits, a week or more apart are required, the first one for a test fitting.
On the first visit, the patient fills out a registration form which is the beginning of a record similar to any kept by a medical doctor. A short history is recorded.
An impression of the shape of the affected eye and surrounding tissues is made with a creamy material (alginate) that sets up within 2-3 minutes without discomfort to the patient. It reaches a consistency similar to the white of a hard boiled egg. After removal of the impression from behind the eye lids, a mold of dental stone, a material very much like Plaster of Paris is made of the back surface of the impression that had contacted the eye.
A large shell, similar to a scleral contact lens is formed over the dental stone model of the eye and surrounding tissues, usually by pressing a heat softened sheet of transparent
Plexiglas down over it. The edges and front surface of this shell are smoothed and the entire shell is highly polished before inserting it in under the eyelids for the first time. It may be removed and altered if it is not entirely comfortable upon initial insertion. The shell is then worn for a time until the nerves in the surrounding tissues become adjusted and the sensations reduced to a very acceptable point. The patient is taught how to remove and reinsert the shell and returned home with instructions to wear the shell only during waking hours (leaving it out at night) for a period lasting until time for the appointment to fit and fabricate the final shell.
The second visit, for the fitting for the final shell, will require the patient's presence for at least two days. Rarely, one or more additional days might be required.
In the final fitting, the front surface of the shell will be modified to help contour the eyelid margins and achieve the desired prominence for symmetry with the companion eye.
When all the improvements possible have been made, a new, final two-piece mold of dental stone is made around it in a strong bronze flask. it is opened and the refitted test shell is removed. A dough of white plastic (acrylic) is packed in the mold and processed by heat and pressure until it is cured and hardened. This, then, constitutes the beginning of the final protective, cosmetic shell prosthesis.
A thin layer of plastic is ground, filed and sanded from the front surface of the eye so that, after tinting with color and placement of red cotton threads to simulate blood vessels, a protective layer of transparent acrylic can be cast over the front surface to bring the form back to exactly the shape of the final test shell.
The coloring of the prosthesis is done with the greatest care to match the companion eye and to present an appearance of living tissue. This is done by a' method devised by us in October, 1976 and used exclusively by us and a few of our former apprentices. The patient must be present for this part of the work for perhaps two or more hours. At intervals, the painted prosthesis can be made to have it's final shape and to look as if completely finished. This is done with a temporary, removable layer of transparent acrylic. It can be placed behind the eyelids to be judged with all illusions present, then removed and the temporary layer lifted off and the coloring can be altered. This step can be repeated until the coloring is fully satisfactory.
When the color is judged to be correct, the shell is returned to the mold and the final layer of transparent acrylic mentioned earlier is permanently cured to it's front surface to protect the color during polishing and wearing.
The finished, highly polished prosthesis is placed behind the eyelids and judged in all respects. If it is not right in every way, changes can be made until it is not possible to improve it further. While most other eye fitters take less time, we find that we can produce far superior prostheses, in all respects, by using this time consuming, painstaking method.
When scarred eyes, phthisical globes or congenitally abnormal eyes are fitted by this very specific, special method, the chances of wearing the shell during the entire waking hours in comfort are nearly 100%.
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