|Year : 1969 | Volume
| Issue : 6 | Page : 266-269
Evaluation of ocular prosthesis
BS Goel, D Kumar
Institute of Ophthalmology and Gandhi Eye Hospital, Aligarh, India
B S Goel
Institute of Ophthalmology and Gandhi Eye Hospital, Aligarh
|How to cite this article:|
Goel B S, Kumar D. Evaluation of ocular prosthesis. Indian J Ophthalmol 1969;17:266-9
It has been commonly observed that ocular prosthesis generally fitted do not conform to the desirable standard of perfect fitting and matching. In the present communication we have tried to evaluate the various types of ocular prosthesis fitted by us in 1,052 eyes over a period of last ten years.
| Types of Ocular Prosthesis|| |
1. Artificial Eye : - 534 patients who had one of their eyeballs enucleated or had grossly phthisical eyes, have been provided with artificial eyes. These are Snellen type of preformed eyes which vary in thickness from 2-10 mm and in size from 12 x 14 to 28 x 30 mm, the vertical side being the smaller one with a notch on the upper nasal border.
2. Moulded Eye :-In patients where a satisfactory fitting is not possible with the conventional type of artificial eyes described above, a moulded eye affords better results. Moulded eye is prepared from an impression of the socket or the phthisical eye if present. 94 eyes have been provided with moulded eyes.
3. Cosmetic Contact Shell:-This is an opaque contact lens painted for all the anterior segment details including conjunctiva and sclera. It requires all the fitting techniques and procedure of a scleral contact lens. This is given in cases who have normal or nearly normal shape of the eyeball having total corneal opacity or a disfigured eye where useful vision is not possible. These are extremely thin shells varying in thickness from 0.50-2.50 mm depending upon the contour and shape of the eyeball.
4. Cosmetic Contact Lens :-This is akin to a cosmetic shell except that the pupillary area is left clear for visual purposes and is suitably powered to correct the refractive error. The scleral portion in such cases is also transparent. 117 patients were provided with cosmetic contact lenses for various reasons.
5. Spectacle Prosthesis :-It is an ocular prosthesis attached to a spectacle frame and is indicated in cases whose sockets are markedly contracted beyond reasonable repair and cannot retain even the smallest eye or have been subjected to exentration. 5 spectacle prosthesis have been prepared for different types of patients.
| Functions of a Prosthesis|| |
A well fitting prosthesis is essential for functional integrity of the socket and the eye, rather than being purely cosmetic. It has the following functions.
1. It should retain the shape of the socket and prevent prolapse of the fornices.
2. It should retain the shape of the lids allowing full movements of the lids.
3. It should provide proper muscular action of the lids and thus help in tear flow.
4. It should prevent accumulation of fluids in the rocket.
While keeping the above in view, an ocular prosthesis should fulfil the following conditions, as basically they are a cosmetic appliance for the patient and should be acceptable to the patient as such.
1. The palpebral aperture should appear to be the same as in the fellow eye. A large palpebral opening creates a staring effect.
2. The size and shape should be such as to allow full movements of lids and their complete closure.
3. Maximum motility of the prosthesis should be attained.
4. No deviation should be apparent.
5. The pupil and iris should be properly matched with the other eye.
6. The pattern of the conjunctival vessels and the tint of the sclera should be similar.
7. Prosthesis must be comfortable when worn and patient should not become aware of it.
Having considered the basic points in the fitting of an ocular prosthesis, we are now in a position to evaluate the suitability of the various types of prosthesis.
| Preformed and Moulded Eyes|| |
It has been commonly seen in our practice that maximum number of patients require either preformed or moulded artificial eyes. However it is difficult to draw a strict border line between those suitable for or the other type of prosthesis. The cosmetic and functional results are best, if the fitting is done at the earliest opportunity. However it has been seen in a large number of cases that surgeons fit stock eyes irrespective of aims and objects of proper fitting. The prosthesis so worn have been found either too big damaging the fornices or too small causing their contracture. It is thus important that each case is fitted with an individually prepared eye and use of stock eyes as such should be discouraged except temporarily till the proper fitting can be done.
Our analyses shows that about 50% of the cases who attended for the prosthesis had already had their eyes enucleated. This shows the high incidence of enucleations being done even of quiet phthisical and staphylomatous eyes due to possible complications like sympathetic ophthalmia, flare up of inflammatory process and possible chnces of an eye harbouring a malignant tumour. Such a procedure is not called for unless absolutely indicated. We recommend retention of the eyeball whenever possible so that a better prosthesis can be fitted.
It has been observed that artificial eyes fitted after simple enucleation lack good cosmetic appearance and do not have an appreciable motility, whereas a moulded eye fitted over "phthisical eyeball stumps" provide comparatively good motility to the prosthesis and better cosmetic appearance. It is because of the fact that a phthisical eye has all the muscles attached, which provide reasonable movements. On the other hand if an enucleation is essential, an intra-orbital implant should be provided though it does not form such a good stump as a phthisic eye for mobility of the prosthesis. To avoid post operative shallow fornices due to scarred or injured conjunctiva, a conformer should be used post-operatively to avoid contractures. Apart from fitting difficulties, certain other disadvantages are also encountered in enucleated sockets viz. excessive shrinking of the orbital fat, retraction of the upper lid sulcus, ptosis, loss of fornices, sagging of the lower lid with consequent extrusion of the eye during forcible closure of the eyelid, displaced or extruded orbital implants and symblepharon. However with slight effort, the fitting can be made nearly perfect but in any case would not match the results in patients where phthisical eye is retained.
| Cosmetic contact Shell and Contact Lenses|| |
These two types of prosthesis are ideal wherever possible to fit. The basic fitting technique and processing are the same as for scleral contact lenses. It is possible to fit cosmetic shell and cosmetic lens in extreme degrees of opacities and in badly looking eyes, provided they maintain reasonably good shape. Cosmetic contact lenses are prescribed where the patient has some vision and is desired to be retained through normal or abnormally placed pupil. About 50% of patients attending for prosthesis, were suitable for cosmetic contact lens or shell. Since the eye has normal or nearly normal shape with full movements, the prosthesis maintains all the movements and functions of the eyeball and the lids, provided it is not too big to mechanically hinder the motility. It has been observed that the cosmetic shells give excellent results and we would advocate these for all cases whenever possible. Enucleation as such is not desirable in all such cases at the cost of cosmetic results. Our follow up has revealed no chances of sympathetic ophthalmia or flare up of inflammatory process in otherwise quiet eyes. Since incidence of malignant melanoma is negligible in our country, we can safely keep such eyes and avoid enucleation as far as possible. We have attempted fitting cosmetic shells even in staphylomatous eyes with a slight bulge of the cornea. In such cases making the shell extremely thin at the cornea may mask the buldge. In gross staphyloma, preliminary staphylectomy under Cortico-Steroid cover has been attempted followed by usual fitting procedures, after 6-8 weeks. Since the method involved no risks, the results have been satisfactory. We do not recommend enucleation of even such deformed eyes.
Eviscerated eyes with scleral balls have nothing special than fitting an eye with a cosmetic shell. But in our experience this procedure has not been a great success, due to quite frequent extrusions. Simple evisceration leaves a stump and a socket which is usually ideal for a moulded eye rather than a shell.
| Spectacle Prosthesis|| |
Such a prosthesis is only cosmetic as it is placed over the socket attached to a spectacle frame. Even in a grossly contracted socket, an artificial eye fitting has been attempted after surgical reconstruction. This has been a common experience that reconstructed sockets do not provide a good base for ideal fitting because of shallow fornices, narrow palpebral aperture, imperfect closure of the lids and extrusion of the eye. However in extreme degrees of contractures, particularly following severe burns of the face, where hardly any results were expected even after major plastic surgery and after exentration, a spectacle prosthesis was provided so that when the patient wears the spectacles, the prosthesis covers the socket and fairly matches the other eye.
| Role of Spectacle Glasses in Ocular Prosthesis|| |
In certain cases where either the ocular prosthesis has been slightly larger, smaller or prominent, a good cosmetic result has been obtained by giving plus lenses for small prosthesis and minus lenses for larger ones so that the ocular prothesis matches the size of the sound eye. Even horizontal and vertical width of the palpebral aperture is slightly altered by prescribing high cylindrical lenses at the proper axis. It has been further observed that in cases who use spectacles for the other eye, the same prescription should be given for the artificial eye as well so that both eyes are apparently alike.
| Artificial Eye Fitting in Children|| |
Care must be taken to give prosthesis of proper size to children to avoid atrophy of the orbital fat, retarded growth of the orbital bones and subsequent contractures of the fornices. Frequent check ups and change in the prosthesis, if necessary, should be done.
| Prosthesis Fitting in Deviated Eyes|| |
In small degrees of deviations, it is often possible to fit a prosthesis without preliminary surgery by slightly eccentric placing of the cornea so that the visual axises appear parallel. This usually does not interfere with the ocular motility. However in case the eye is grossly deviated, a preliminary squint correction is advisable.
| Summary|| |
In view of the controversy regarding enucleation of the blind eyes (phthisis bulbi, anterior staphyloma and total corneal opacities) for fitting of ocular prosthesis, we are reporting our experience in such cases. The study deals with 1,052 cases fitted with preformed and moulded eyes, cosmetic lenses and spectacle prosthesis. In anterior staphyloma and total corneal opacities, the cosmetic shall has been provided which has afforded excellent cosmetic appearance and full ocular movements. As such these cases do not require enucleation, because this does not result in equivalent restoration of cosmetic appearance.