|Year : 1983 | Volume
| Issue : 4 | Page : 455-457
Intra-scleral motility implant
20, White Church Colony, Residency, Indore, India
20, White Church Colony, Residency, Indore
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Kalevar V. Intra-scleral motility implant. Indian J Ophthalmol 1983;31:455-7
Appearance has always been a very important factor in human life. It is true that appearance goes a long way in social and professional status.
Ophthalmologists all over the world face a refusal by patients when removal of an incurably blind eye is advised because of fear of sacrificing the eye and consequential defect in appearance.
Traditional enucleation and evisceration leave behind an empty socket which is far from acceptable from cosmetic point of view. An artificial painted shell fitted in such sockets, even if retained properly, has far from satisfactory motility or none at all. Its artificiality can he made out easily.
| Material and method|| |
The procedure described herein overcomes many of the disadvantages desribed above and has a distinct advantage that the extraocular muscles are left in their normal anatomical position without any disturbance whatsoever and still more important is that the scleral -shell is not allowed to shrink and collapse but retains its contour over which the prosthetic shell fits far better. This gives nearly 75 to 80% motility to a properly fitted cosmetic shell The procedure in short is described below:
The preparation of patient is as for any major ocular surgery. It is advisable to execute the surgery under general anaesthesia or in an adult, under local anaesthesia with adequate sedation.
Introduce an eye speculum so as to maximally expose the operative field.
Incise conjunctiva all round the limbus and undermine it upto the rectii insertions. Indentification and separation of Tenon's capsule from conjunctiva will be helpful, although this is not always possible in the clinical conditions one has to deal with.
Incise at one sector of limbus and deepen the incision to perforate full thickness of limbal sclera. This may be a stab incision or an ab-externo incision.
A broad iris repositor should be introduced to explore the anterior chamber and also separate iris adhesions if any.
Limbal incision is enlarged with spring scissors concentrically to remove the entire cornea.
At this stage, depending on the clinical condition, the intraocular contents in toto or without the iris diaphragm are exposed.
Edge of sclera is held firmly and a blunt instrument, I use a narrow vectis, is passed all round in the suprachoroidal plane to separate the loose attachments between sclera and choroid as well as the vessels and nerves in the supra choroidal space.
A wide suction catheter is now used with one hand and the other hand separates the attachment of choroid at the posterior pole of the eye ball.
This technique ensures complete removal of intraocular contents en-mass. It also obviates the need to scrape the inner scleral surface to remove choroidal ramnants. However some scraping is necessary if there is incarceration of uveal tissue in a scleral scar such as in cases of perforating wounds.
Some bleeding is inevitable when the uveal coat. enclosing intra-ocular contents !s separated and removed because of the torn ciliary, vortex and central retinal vessels. This is taken care by suction and a gauze pack in the scleral shell is kept pressed for a few minutes.
Antibiotic powder insufflation in the scleral cavity follows.
An adequate sized spherical implant is now introduced in the scleral cavity. The size is decided on the basis of available scleral cavity and not on the basis of anterior scleral opening, which, if necessary, as usually it is, can be enlarged by a 5-7 mm radial cut in the sclera between any two recti muscles This helps easy placement of the implant in the sclera.
The size of the implant should be such that it occupies the available intra scleral space and yet the edges can be opposed to cover the implant anteriorly. Too tight filling of the scleral cavity is not advisabie because some amount of scleral shrinkage is expected.
One suture with 5-0 braided silk at the anterior ends of the radial scleral incision is applied to get the round opening of scleral cavity. The remaining extent of this incision can be sutured later. After tying the first suture we usually continue the same needle along the circumsference of the anterior circular opening in a purst~.string suture. This is tightened to close the scleral sac completely and finally tied to the short stump left at the first suture of the radial incision in the sclera. To obtain extra security, two or three interrupted sutures are added. The remaining posterior extent of radial scleral incision is closed with adequte number of interrupted sutures.
Conjunctival and Tenon's edges alround are now defined and pulled forwards to cover the stuffed scleral shell. Whenever possible, they are sutured separately.
The conjunctival incision is sutured horizontally with interrupted 6-0 silk. If these sutures appear to be under tension, horizontal release incisions, about 5 mm above and below the conjunctival suture line are given to avoid the possibility of conjunctival sutures giving way pre-maturely.
With firm scleral closure and secure conjunctival coverage, chances of extrusion are few. Post-operative period is usually uneventful. Sometimes lid swelling and conjunctival chemosis occur which quickly respond to anti-inflammatory therapy.
Conjunctival sutures are removed after a week.
A considerable advantage of this procedure is its simplicity of execution, availability of mobile stump, and adequate fornix spaces for proper fitting of a painted shell.
In long standing pothisical eyes, this procedure can not be done because available scleral cavity is inadequate to accomodate even the smallest size of spherical implant. Even if the procedure is done, chances of extrusion are greater.
if intraocular contents are removed en masse, danger of sympathetic ophthalmitis is none at all or minimal.
A matching painted contact shell prosthesis can be used after 2-3 weeks post operatilely. Whenever feasible, it is important to take a mould so that the prosthetic shell fits well and the motility is maximal.
Other important guide lines to the prosthesis manufacturer are suggested. These have been considered important from cosmetic point of view and have come to mind after observations over the last 10 years.
1. Corneal diameter of the normal eye
should be strictly reproduced on the prosthesis.
2. Corneal position of the normal eye in primary gaze if also important to avoid an effect of squint.
3. Measurement in mm from lateral orbital margin to the apex of cornea of normal eye, like in exophthalmometry, is another important measurement for the anterior convex curvature of the prosthesis to be same as that of the normal eye. If this is not taken care of, an unequal prominence or otherwise results
4. Lastly, of course the colour of iris in the normal eye must be reproduced on the prosthesis.
All these add to the attainment of a good cosmetic result. Manufactures of artificial shells should make an attempt to have an A.C. space to give a more realistic appearance.