|Year : 1958 | Volume
| Issue : 1 | Page : 9-11
Some observations in keratoplasty
King Edward Memorial Hospital, Bombay, India
|Date of Web Publication||8-May-2008|
D G Mody
King Edward Memorial Hospital, Bombay
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Mody D G. Some observations in keratoplasty. Indian J Ophthalmol 1958;6:9-11
At the outset I must make it clear that this is a brief paper containing our observations in a very small series of cases, written with a view to state our experience. Since the suspension of all keratoplasty work by orders from the Government, until the Anatomy Act is changed, there does not seem to be any hope of gaining further experience in the near future. Various experiments have been made to solve the problem of so-called idiopathic opacifications of the graft or the 'graft-disease' which leads sooner or later to opacification of grafts, and yet no satisfactory solutions have been found. This universal difficulty has made me analyse my six successful cases in retrospect so that we may approach the problem of postoperative opacification of the graft.
The following is an analysis of our successful cases in order to note observations that might have contributed to the clarity of the grafts.
| Analytical Study|| |
Donor material : In all cases the donor material was obtained from enucleated cadaver eyes stored at 4° C. It is observed that except in one case where the cornea was used 16 hours after storage, in all the cases the period of storage was between 24 to 45 hours. As per Filatov's hypothesis, storage seems to improve the condition of the cornea and it acquires the capacity to survive in adverse conditions and has therefore better chances of survival in recipient eyes. I think this is a very important factor and may contribute by large in the subsequent clarity of the graft. The linear opacity which develops in the donor's cornea due to hypotension in the stored eye leading to folds of Descemet's membrane should not deter one from using that cornea.
Andrew de Roeth (1950) in his very interesting study of metabolism of stored cornea concludes that from the biochemical point of view the cornea remained normal for a longer period in the excised state (i.e. cornea stored after removal from donor's eye) than in the intact state (i.e. whole eye-ball stored). But it must be noted that the corneas stored in the excised state are inconvenient to handle for transplantation purposes. Moreover, most surgeons use only 24 to 48 hours old donor material during which time there is little if any difference in the metabolism of the excised and intact corneas.
| Selection of Cases|| |
It is clear from the above table that five of the cases belonged to the unfavourable group. Thus contrary to the usual belief that the recipient's cornea round the bed of the graft should be transparent and healthy for a successful result, I found that in all five cases where this condition was not fulfilled, the grafts did remain clear. Hence we may presume that this so-called important factor is not of great value for the subsequent clarity of the graft and that there are other factors more important for the eventual clarity of the graft. Clearing of recipient's cornea around the corneal graft was observed in my cases and other workers have also observed similar changes; this could be due to the production of a biologic stimulant by the stored donor cornea acting on the opaque lamella of the recipient's cornea. In the series of experiments carried out on rabbits by Max Fine (1950), it was noted that out of 6 animals where partial penetrating Keratoplasty was done this effect of clearing of recipient's cornea around the graft was observed in four animals, while in cases of non-penetrating type of Keratoplasty this effect was not observed. Hence he concludes that some circulatory and metabolic changes produced by the operation itself may be responsible for the clearing effect and that only presence of homologous tissue alone is not the complete stimulus for such clearing.
| Pre-Operative Treatment|| |
Superficial vascularisation was noticed in all the five unfavourable cases to a varying degree. I did peridectomy in all these five cases. My technique which is different slightly from that described is as follows :-
A strip of 4 to 5 mm. of conjunctiva adjacent to the limbus in the vascularised zone is excised. If this is extensive, operation is done in two stages. After the conjunctival strip is excised the feeding vessels on the cornea are seen with a loupe and each vessel is split up vertically with a sharp pointed knife and then cauterised. This procedure does away thoroughly with all the vessels which had persisted after having done their defensive work during the active stage of the corneal lesion. In my opinion this procedure is superior to β radiation and must be carried out even if there is a single feeder. This prevents the post-operative vascularisation and opacification of the grafts.
| Operation|| |
One of the most important factors though recognised by every one but not rigidly adhered to, and on which subsequent clarity of the graft depends to a great extent, is the extreme sharpness of the trephine. Flawless excision of the cornea in the donor's and in the recipient's eye is of utmost importance to the final outcome of a partial penetrating corneal transplantation. The use of Franceschetti's adjustable hand trephines with an inner piston proved to be of great advantage. This instrument prevents., sudden outflow of aqueous and the danger to the lens is minimised by a device which regulates the height of the trephine crown. (Lindner (1950) suggests injection of saline into anterior chamber during the trephining procedure to prevent lens injury).
Size of the Graft : It is my conviction that the size of the graft should not exceed 7 mm. and for two reasons, viz, larger the graft, it requires more nutrition and secondly, the pupil under strong mydriasis usually does not dilate beyond 5 to 7 mm. and therefore chances of iris getting incarcerated in the wound are more.
Retention of Graft : In all cases cross limbal sutures were used for retention of the graft. Direct corneal suturing does not appeal to me because of the resulting trauma to the delicate corneal tissue.
| Post-Operative Treatment|| |
The usual post-operative treatment was carried out in all cases. I would like to mention here the beneficial effects of foreign protein therapy and instillation of carbachol drops locally. All my cases received either milk injections or T.A.B vaccine or both. In one case after one milk injection the patient kept on getting repeated bouts of fever of unknown origin. However, the patients eye condition showed remarkable improvement, the eye became quiet more quickly and the graft more clear and has remained so, for the last four years.
As regards carbachol (0.75% solution) it was instilled in the eye whenever the dressing was done and later two or three times a day for about a month. I observed that the clarity and luster of the graft improved with the use of this drug. In two cases not operated by me where cloudiness had appeared in a portion of the graft I tried this drug with beneficial result. I am of opinion that carbachol being a vasodilator improves the nutrition of the cornea and helps in corneal metabolism.
| Summary|| |
A clinical analytical study of six cases of full-thickness corneal grafts is presented, Offering suggestions for the probable factors that go to make this operation successful.
| References|| |
De.Roeth A(1950) Arch Opth 44.659-665.
Linder, K (1950) Arch.Opth 43:769.
Max Fine:(1950) Arch .Opth,43:1065.
[Table - 1]