Impression Moulded Custom Plastic Scleral Shell Prosthesis

A scleral shell ocular prosthesis is an artificial eye that is worn over a blind, disfigured, and/or phthisical (shrunken) or congenital microphthalmic globe.
The process to fabricate a scleral shell prosthesis requires two phases:
Phase I is the fabrication of a custom clear acrylic ocular conformer. The patient is instructed to build up their wear time with this conformer, to ensure that they can comfortably wear the prosthesis over their blind, phthisical/microphthalmic globe.
Then, during Phase II, the patient is seen for additional appointments to fabricate a hand-painted, custom fit Scleral Shell Ocular Prosthesis.

Phase I: Impression Moulded Clear Acrylic Ocular Conformer

Evaluation: Your initial appointment in our office will be for the evaluation of your blind, scarred, disfigured and/or phthisical (shrunken) eye for the eventual wearing of a Scleral Shell type Ocular Prosthesis. If, at this evaluation, it is determined that you may be a candidate for such a prosthesis, the following procedure will take place.

Impression Molded: An impression molding will be taken of your globe with an alginate material similar to what is used in dentistry. The alginate impression will then be used to make a dental stone copy of your eye. Then, a clear acrylic conformer will be fabricated. This conformer will match the contour of your eye, while the conformers’ anterior surface will have a near normal curvature to that of your fellow eye. The thickness of the conformer will be dependent up on the present size and shape of your anomalous globe.

Goal for the use of the Clear Acrylic Conformer: The purpose of the conformer is two-fold: TOLERANCE and COMFORT. The initial fitting of the flush-fitting conformer will give us a good idea as to the tolerance level of your blind eye. The ability to wear such a conformer comfortably, however, can only be assessed by your wearing it over a gradually controlled number of hours, days, and weeks.

Wearing Schedule: The usual schedule for wearing a custom clear conformer is one hour the first day, and increasing 30 minutes of wear time per day until you are able to wear the conformer for a minimum of eight hours per day with comfort. A wearing schedule, along with instructions for insertion, removal, and hygiene care will be given at your ocular conformer fitting appointment. Upon completion of the successful wearing period (approximately 6-8 weeks), additional appointments will be made for the fabrication of the color matched scleral shell type ocular prosthesis.

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Phase II: Custom Plastic Scleral Shell Ocular Prosthesis

What is a Scleral Shell Ocular Prosthesis? It is an impression molded, flush-fitting ocular prosthesis made of plastic (polymethyl methacrylate or PMM). It is specifically designed and fashioned to be worn over an eye that may be blind, scarred, disfigured, and or/deviated in size and shape.

Objective of the Scleral Shell Ocular Prosthesis: It is a multi-purpose ocular prosthetic device for congenital and acquired anomalies for:

Therapeutic: dry eye syndrome, lagophthalmos, photophobia, trichiasis, levator stress caused by phthisis
Surgical Prevention: eliminates orbital content disruption of evisceration or enucleation, acquired pseudo-blepharoptosis, prolapse and ectropion of the lower lid, congenital microphthalmos with microphthalmic palpebral fissure.
Protective Cover Shell: intermediary for future surgical procedures
Cosmesis and Comfort: physical and psychological well-being of the patient

Size and Shape: The scleral shell ocular prosthesis is an impression molded artificial eye device that is placed over a live eye. The cover shell may be as thin as .2mm if placed over a normal or exophthalmic (protruding) eye, or of varying thickness if placed over a phthisical (shrunken) globe.

Length of Wearing Time: The degree of corneal sensitivity in any size globe is a variable, and as such will determine the length of wearing time with the scleral prosthesis. The Phase I wearing schedule with the “Impression Molded Clear Acrylic Ocular Conformer” determines the extent of wearing time from a limited number of waking hours to 24-hours or longer.

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Frequently Asked Questions: Scleral Shell Prosthesis

Does the scleral ocular prosthesis have any therapeutic purpose?

Yes, it can provide physical comfort and relief to patients with dry eye syndrome, photophobia, and trichiasis. It also provides a lifelike duplication of the fellow eye, which is psychologically comforting to the wearer.

Are there any other benefits derived from wearing such a cover shell over a dysfunctional globe?

Yes, it can prevent surgical disruption (evisceration or enucleation) of the orbital contents. It can also non-surgically relieve the external adnexa by elevating a pseudo blepharoptosis (sagging upper eyelid) caused by global volume loss (phthisis), and in some cases reduce ectropion by providing support to a prolapsed lower eyelid.

If I have a very sensitive cornea and cannot pass Phase I with wearing comfort, but I still want this type of prosthesis, what is my next option?

Using a Gundersen conjunctival flap to protect the cornea would be the next option. A conjunctival flap eliminates any corneal sensitivity, and you would be able to wear the completed scleral prosthesis all your waking hours. This matter can be discussed with your ophthalmologist.

Is it possible to wear a soft cosmetic corneal contact lens over a blind disfigured eye?

Yes, if it is only the cornea that is scarred or disfigured. The best cosmetic result would also require no loss of global volume, and the eye have an aligned catoptric image (not be deviated). We are not able to provide patients with soft cosmetic lenses, only hard plastic scleral shell covers.