Pardeep Khurana*, Kiranmeet Kaur Sodhi**
How to CITE:
J Pak Dent Assoc 2010;19(4): 220 – 223
Abstract
Ocular prosthesis is an artificial replacement of the eye. After enucleation, evisceration and exenteration of the eye, the goal is to replace the missing tissues with an artificial prosthesis and restore the facial symmetry and normal appearance of the anophthalmic patient. Eye loss causes disfigurement of the face due to which individual become emotionally weak and conscious and avoid taking part in social events, which in turn causes anxiety, stress and depression at an early age in life. Recovery after the loss of an eye requires an adjustment to monocular vision and improvement of the appearance with the use of artificial eyes . The custom made ocular prostheses are very comfortable and help individual improve their appearances, which in turn, encourages them to build up their self-confidence to return back to their social life.
Introduction
Eye loss may be because of irreparable trauma, tumor, a painful blind eye, sympathetic ophthalmia, or the need for histologic confirmation of a suspected diagnosis.1 Depending on the severity of the situation, the surgical management may include one of 3 approaches: evisceration, enucleation, or exenteration. Evisceration is the surgical procedure wherein the intraocular contents of the globe are removed, leaving the sclera, Tenon’s capsule, conjunctiva, extraocular muscles, and optic nerve undisturbed; the cornea may be retained or excised.2 Enucleation is the surgical removal of the globe of the eye and a portion of the optic nerve from the orbit.2
The choice between evisceration and enucleation may be difficult, because the indications for each operation are not always clearly defined. Enucleation is often considered the treatment of choice for primary intraocular malignancies because it permits histopathologic examinationof the intact globe, as well as determination of intraneural or extrascleral spread of the disease.2 Orbital exenteration is the en bloc removal of the entire orbit, usually involving partial or total removal of the eyelids and is performed primarily for eradication of malignantorbital tumor.2 The disfigurement associated with the loss of an eye can cause significant physical and emotional problems.3Most patients experience significant stress, primarily due to adjusting to the functional disability caused by the eye loss, and to social reactions to the facial impairment. Replacement of the lost eye as soon as possible after healing from eye removal is necessary to promote physical and psychological healing for the patient and to improve social acceptance. A multidisciplinary management and team approach are essential in providing accurate and effective rehabilitation and follow-up care for the patient.
Therefore , the combined efforts of the ophthalmologist, the plastic surgeon, and the maxillofacial prosthodontist are essential to restore the patient’s quality of life. The importance of an ocular prosthesis with acceptable esthetics and reasonable motility in restoring normal appearance in patients with anophthalmia has long been recognized. Anecdotal reports and relics from ancient civilizations indicate that the restoration of ocular defects may have existed for thousands of years. The earliest known examples of restorations date to the Fourth Dynasty (2613-2494 B.C.) in Egypt; excavation of tombs provided evidence of eye replacement by using precious stones, earthenware enameled bronze, copper, and gold in the shrunken sockets.4 In the 16th century,Pare´ fabricated an ocular prosthesis (”emblepharon”)made of gold or silver.5 Pare´ also used glass and porcelain for eyes, which was a great
step forward and resulted in the use of the shell type of pattern rather than spheres.6 Glass remained the most popular material until the adventof World War II, when it was difficult to obtain glass or glass eyes from Germany. Methyl methacrylate, which had already replaced vulcanite as a denture base material, seemed to be a good replacement material. A definitive technique for fabricating artificial eyes using acrylic resin was developed by the United States Naval Dental and Medical Schools and was published in 1944.7 Unlike glass eyes, the acrylic resin eyes were solid. The material was lightweight, easy to fit and adjust, unbreakable, translucent, easily fabricated, had intrinsic and extrinsic coloring capabilities, and was inert to the socket secretions. 6
The dental-prosthetic influence in the development of this prosthesis accounts for the ocular prosthesis being fitted from an impression of the eye socket rather than by the traditional empirical method.8 Several techniques have been used in fitting and fabricating artificial eyes. Empirically fitting a stock eye, modifying a stock eye by making an impression of the ocular defect, 9 and the custom eye technique10 are the most commonly used techniques. The fabrication of a custom acrylic resin eye provides more esthetic and precise results because an impression establishes the defect contours, and the iris and the sclera are custom fabricated and painted.
TECHNIQUE
The patient’s history, including medical history and etiology for the loss of eye was taken. This is very important because if the eye loss was due to any malignancy then one has to be alert for any evidence of
recurrence during initial and subsequent visits. The eye socket was then examined to check for complete healing of the surgical wound and also to see if any oedema and inflammation existed
Impression Procedures: The impression of the socket was made with a light viscosity polyvinyl siloxane impression material, with an auto-mixing device (Contrast, Voco, Germany). Before making the impression, a thin layer of petroleum jelly was applied around the eye socket to prevent the impression material from sticking. The material was then injected slowly into the socket and the patient was asked to perform various eye and eyelid movements to facilitate the flow of the impression material into all aspects of the socket. The impression was carefully removed from the socket once the material had set.
Cast: The impression was poured in three sections. First the upper third of the impression was immersed. After the stone had set, keyholes were cut and boxing was done around the first layer using modelling wax after which separating medium (Cold mould seal, Dental Products of India Ltd.) was applied. Then a second layer was poured to cover the middle third of the impression. Again keyholes were cut and separating medium was applied. Then the final pour was made. After it had set, the three sections were separated and the middle layer was sawed and separated into two halves in order to remove the impression.
Wax pattern: The second and the final layer of the cast were assembled and immersed in water for few minutes. Molten wax (Modelling wax, Hindustan Dental Products Ltd.) was then poured into the cast. Once the wax hardened, the mould was opened and the wax pattern was removed. Sharp ridges and undesirable irregularities were Eliminated and the portion of the wax that represented the palpebral fissure was re-contoured to form a smooth convex surface.
Try- in of the wax pattern: The wax pattern was inserted into the patients socket to check for proper contour and bulk. Necessary modifications were done, re-polished and again inserted into the patient’s eye socket. This was done until the soft tissue contour and the palpebral tissue resembled the patient’s natural eye. The patient was then made to look straight ahead at a distant point and landmarks were marked on the wax pattern for the placement of the prefabricated iris button (Name of manufacturer and address details CAMALIN, MUMBAI INDIA) of appropriate size and similar shade provided by the ophthalmologist. Then a space was created on the wax pattern and the prefabricated iris button was placed and the wax was again smoothened. The wax pattern was again placed in the socket and compared with the opposite eye of the patient. Once the soft tissue contour and the location of the iris were satisfactory, the pattern was removed and the shade for the scleral portion of the prosthesis was selected using tooth coloured acrylic shade guide.
Polymerization : Flasking and dewaxing was carried out in a usual manner taking care that the iris button was secured firmly to one compartment of the flask. Heat cure acrylic resin (Stellon, Dental Products of India Ltd.) of appropriate shade was used and after doing a trial closure, stains and veins were added to give a more natural appearance of the artificial eye. After the final closure, the processing was done by a slow curing cycle. After recovering the prosthesis it was polished to get a smooth
and shiny surface. On the final appointment the prosthesis Was inserted into the patient’s eye socket.
Instructions to the patients: The patient (for a child the parent) was taught the proper method of removal and insertion.
- Removal is done by pulling the lower lid down, gazing overhead and engaging the lower margin of the prosthesis with one finger so that it is expelled downward in to hand.
- Insertion is done by lifting the upper lid with the thumb and forefinger, sliding the prosthesis with other hand as much as possible under the upper lid and pulling the lower lid down to allow the prosthesis to slip into the socket
- The patient was instructed to wear the prosthesis day and night, removing and washing it with a mild soap once a day.
To improve the movements of the eyelids and to get a sparkle on the surface of the prosthesis, use of an ophthalmic silicone liquid was advised
Conclusion
Rehabilitation of patients with eye prosthesis who have suffered the psychological trauma of an ocular loss require a prosthesis that will provide the optimum cosmetic and functional result as early in life as possible
The custom made ocular prosthesis is recommended as an effective alternative form of treatment. Ocular prostheses produced by this method are the most aesthetic and comfortable and they should be provided for all patients who require such prostheses.
References
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