|Year : 1983 | Volume
| Issue : 5 | Page : 588-590
Paralimbal scleral window-A new surgical approach to incurable corneal blinds
Department of Ophthalmology, Medical College, Amritsar, India
Department of Ophthalmology, Medical College, Amritsar
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Singh D. Paralimbal scleral window-A new surgical approach to incurable corneal blinds. Indian J Ophthalmol 1983;31:588-90
A patient is considered incurable corneal blind when he does not stand even a remote chance with commonly used procedures like optical iridectomy, lameller or penetrating keratoplasty or where all these procedures have failed. Such patients may have a gross deformity in the anterior segment like partial or total anterior staphyloma. The corneal tissue if present may be grossly scarred and vascularised. The iris is usually damaged, scarred and atrophic, the lens if present may be cataractous. The gross deformity of the anterior segment may be responsible for raised intra-ocular pressure.
The light perception may be good but the projection may not always be good due to anatomical abnormalities described. The eye may be squinting.
We have attempted to bye-pass the anterior segment and make a seeing "Paralimbal scleral window" with the hope of improving the visual condition.
| Material and Methods|| |
Total patients: 6
Patient No. 1 2 3 4 5 6
Age & Sex : 20F 9F 60F 50M 45M 50M
Pre-operative vision in all the patients was light perception.
The first four patients were operated as follows:
1. Fornix based conjunctival flap.
2. Scleral opening about 5 mm. from the limbus, size 4 mm x 4 mm.
3. Opening up of the suprachoroidal space around the window. Heat cautery of the subjacent ciliary body.
4. Insertion of a thin flat perspex plate 4 mm x 9 mm. in the suprachoroidal space.
5. Cutting the ciliary body under the scleral window, cutting ,my vitreous if it comes out.
6. Shifting the perspex plate in the area of the opening.
7. Covering the window with conjunctival flap.
In the last two patients the paralimbal prosthesis was in the shape of a collar stud. The inner part of which had aphakic optical correction while the outer part was flat. The design of the prosthesis was worked out by Jan Worst of Holland and the author. It is so made that it can be roughly directed towards the macula, irrespective whether the scleral window is made on the nasal side or temporal side. The fixation is done by stainless steel loops going round the prosthesis and tied to the sclera some distance away. The prosthesis is covered with conjunctival flap.
2 months to 1 year.
| Observations|| |
Patient No. 1: Paralimbal nasal scleral window which is barely visible after one year offers her enough vision to follow somebody while walking and to avoid big animals like cows in the street. She and her mother consider it a worth while gain [Figure - 1],[Figure - 2].
Patient No. 2 She has a temporally placed scleral window. [Figure - 2] Even though her improvement in vision is HM and recognition of colour at 2 metres, she is dissatisfied. The vision of her other eye is 6!60.
Patient No. 3: He had a temporal scleral window. There was an initial gain of HM at 2 meters which has been lost due to the growth of a dense membrane on the surface of the prosthesis. The vision has retreated to good LP.
Patient No. 4: Appreciates no improvement in vision through a temporal scleral window.
Patient No. 5 & 6: One of them has a temporally placed window and the other has a nasally placed window. They are happy at being able to see a large movement of the hand at 6 meters. They can easily count fingers at I meter. In these two cases the conjunctival covering has given way and the flat plate of the prosthesis is partially or completely exposed. There is no sign of extrusion. The steel sutures are holding well.
| Discussion|| |
Many times as in the examples given above the gains of a totally blind patient cannot be counted in terms of so many lines of Snellen's chart. For such patients the advance from perception of light to HM and from total immobility to some mobility is like the landing of "Eagle" on the moon. There is a great boost in morale and self confidence with the slightest gain in sight.
We have chosen the paralimbal area for creating a seeing window for the following reasons:
- It avoids the pathological area of the eye.
- The prosthesis between the sclera and choroid cannot be extruded and thus may permit a chance of permanent gain in sight.
- The conjunctival covering would protect it from external infection and sloughing out.
- In the second approach, using a collar stud like prosthesis, we have relied upon steel suture fixation and conjunctival covering. The initial results have been to our expectations. They give food for thought.
The concept of a paralimbal scleral window for incurable corneal blind patients is new. There is some initial success. There is a possibility that paralimbal scleral window will be an important way of providing useful vision to the incurable corneal blind patients. Considering the needs of millions of incurable corneal blinds, the scope for further studies and application of the concept of scleral window is unlimited.
[Figure - 1], [Figure - 2]