|Year : 1964 | Volume
| Issue : 3 | Page : 99-106
Hazards in keratoplasty
RP Dhanda, VK Kalevar
Corneal Surgery Unit and the Regional Eye-Bank, M.G.M. Medical College & M.Y. Hospital, Indore, India
|Date of Web Publication||13-Feb-2008|
R P Dhanda
Corneal Surgery Unit and the Regional Eye-Bank, M.G.M. Medical College & M.Y. Hospital, Indore
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Dhanda R P, Kalevar V K. Hazards in keratoplasty. Indian J Ophthalmol 1964;12:99-106
Curiosity is stronger than passion and passion overtakes interest. Keratoplasty is not a toy of curiosity for an occasional surgeon to play with. It will be pertinent to say that acquired dexterity in cataract surgery and a training in corneal carpentry with a sense to face disappointments inspite of a job well done, are prerequisites for practising routine corneal grafting.
An experience of 240 keratoplasties performed over a period of nearly four years and the knowledge gained from corneal surgeons abroad, qualifies us to speak on some of the important hazards of this operation a prospective corneal surgeon in India may have to face.
There should be no dearth of donor material in this country. It is not legislations which will help. What is needed is co-ordination and co-operation of those outside the ophthalmic department who in providing an eye to an eye bank should feel pride and interest, as much as the ophthalmic surgeon in receiving it. I repeat that if we have collected 636 donor eyes in 45 months, others should be able to do the same.
Most eyes were removed within 1236 hours after death and we usually use corneas preferably within 24 hours after removal for penetrating surgery and within 48 hours after removal for lamellar surgery. The longest interval since removal in this series has been 121 hours for lamellar and 97 hours for penetrating surgery. The youngest cornea used has been 31 years and the oldest 65 years. Donor eyes from cases of severe burns, dehydration and drowning became nonviable quicker than those from sudden deaths. It is not the time interval since death or removal which is important. It is the condition of cornea that decides the viability and usefulness of the tissue.
The criteria for suitability of recipient eye for corneal grafting have materially changed since our earlier reports (Dhanda/ 1961). Corneal surgeons on the continent and the States would consider any sizeable iris incarceration a distinctly unfaourable factor. We started with the same but yielded to the circumstances because 242 (48.5%) out of the first 500 cases referred to this Corneal Surgery Unit had iris incarceration. If keratoplasty has to contribute to the amelioration of blindness in this country, the fear complex of unfavourability should be reduced to a minimum. We have therefore now included partial leucoma adherens in the favourably acceptable recipients. The table below is a summary of the clinical conditions for which 240 corneal grafts were done : -
It may be noted that according to our newly adopted criteria, 73.4% of the recipients were operated with objective optimism. It may however also be noted, that keratoconus, deep keratitis, dystrophies and herpetic keratitis, the every day indications for keratoplasty to the surgeon in the West, total to an insignificant 14 out of 216 eyes, for whom 240 keratoplasties were done (24 being retransplants). The other eye was blind in 24.4 and diseased in another .26.8 of recipients. 'This will explain our attempts in the most adverse circumstances on cases of total leucoma adherens and partial or total anterior staphylomata, which we call mercy keratoplasty, because this was the only possibility, of improving the eye functionally, no matter how remote were the chances. In such cases, rewards may appear even poorer when one sees a glaucomatous cupping through a successful transparent total corneal graft.
Diappointments may however be more than compensated even if one out of 12 such cases end in visual recovery.
From the etiological point of view, infective corneal ulcers, trachoma, small pox and malnutrition alone were responsible for 84% of corneal pathoiogy. 61.6% in this series had the onset of corneal pathology before the age of 12 years. Keratoplasty in India has therefore to be undertaken in a much younger age group, if squint and 'established amblyopia are not to be the obstacles to visual recovery.
General anesthesia, it is suggested, should be a help rather than a hazard.
A thoughtful anaesthetist can make penetrating surgery compatible with general anaesthesia. Considering the mental and psychological set up and relatively poor co-operation patients in our conditions offer, 91 out of 140 penetrating grafts were done under general anaesthesia, which was a great advantage in maintaining low intraocular tension and helping a ready formation of the anterior chamber by air injection at the end of the surgery. Use of Fluothane (ICI) is of particular advantage in Keratoplasty.
Carpentary of corneal surgery is one subject which is better observed than read before it is practised. Correct use of needle holder, appropriate direction of the needle, proper use of the corneal forceps are intricate points deserving to be studied from close quarters on the surgical table. Important also is the mental peace of the surgeon and an assistant colleague capable of anticipation.
Pre-operative assessment of the thickness of the cornea will help prevent unintentional entry of the trephine into the anterior chamber. The centring of the graft is the most essential step for a good visual recovery.
Lamellar dissection appears easy to the observer but is more difficult for the surgeon. Even a small change in the plane of dissection can introduce enormous astigmatism, in which case though the graft may be clear, visual recovery may have to await months before suitable correction can improve the vision.
Occasional inadvertant perforation in a planned lamellar keratoplasty may create an unmanageable hazard, ending up as a large-sized penetrating one.
Small tiny perforations near the edge and consequent flattening of the anterior chamber need not however always be ended as penetrating. Lamellar surgery may be completed as planned and the anterior chamber restored by injection of air though the perforation. Thickness of a living cornea being 0.65 to 0.8 mm., primary dissection should never be aimed at more than 0.4 mm. Extra layers of the deeper tissue can be safely removed by a second dissection under direct vision with less risk of perforation.
Saftey in lamellar surgery, generally outweighs the many more uncertainties of penetrating grafts and with experience the trend of early reports (Dhanda-1963) has reversed now in favour of more and more lamellar surgery as shown in [Table - 4].
There are no two opinions that in penetrating surgery direct edge to edge stitches, closely placed, are the only secure means to prevent post-operative complications and help to maintain transparency of grafts 6 mm. and more in size. The statement, "all my grafts have successfully taken" is tending to deceive oneself. All grafts do "take" but not all remain transparent.
A stitch every mm. in penetrating keratoplasty alone can safeguard against post-operative flattening of the anterior chamber, formation of anterior synechia and iris prolapse.
Ready formation of anterior chamber at the end of surgery by injection of air or saline is the ONE single surgical step which carries 50% responsibility for ultimate success and to accomplish this successfully, the one single important factor is close edge to edge stitching. A patient should never leave the operation table with a flat anterior chamber. (King1963). This can be better appreciated from the table below [Table - 5].
Again, in Group I, cases in which anterior synechia did occur, improvement of vision was possible in 18.7% of cases.
No improvement at all took place in those cases where air could not be retained readily.
It may be noted that incidence of anterior synechia increased from 29.6% when A.C. readily formed to 100% when air could not be retained.
The following is a picture illustrative of the desired degree of stitching and air retention in the anterior chamber.
In lamellar surgery however stitching is not only simple but lesser number of stitches will hold the graft in place.
Spontaneous dislocation of the lens during penetrating surgery can be a frightful complication more frequently possible where excision of extensive anterior synechie result in a big iris colobma made worse by an optical iridectomy, previously performed. Deepening of anaesthesia at the proper moment, judicious use of scissors in excising the synechiae have helped us in reducing the incidence of this complication from an occasional to a rare one. It is time that it may be taught that optical iridectomy is inappropriate surgery where a possible keratoplasty may be a consideration in future.
[Table - 6] represents the various complications encountered in this series.
Anterior synechia, iris prolapse and iris incarceration in cases of penetrating surgery and epithelial ulcer and vascularisation in lamellar are the most damaging post-operative complications. Small anterior synachia are however compatible with clear grafts.
The small incidence of graft disease (7.7%) may not be a true indication. Some of the opaque grafts with iris incarceration may also be immunological in nature, the sensitizing material having been carried to the graft along the vascular uveal tissue.
The heavy incidence of epithelial ulcers in this series is not easy to explain. Associated trachoma, trophic changes in the surrounding conjunctiva and the extensive corneal pathology providing a recipient bed poor in nutrition may be the possible factors.
Significance of vascularisation will be discussed in another paper.
Excluding mercy keratoplasties and regrafts which carry heavy disadvantages, the successful results in penetrating surgery have been 47.2%. Out of 24 'mercy' keratoplasties for partial or total anterior staphyloma although five grafts remained clear, only two visually improved.
In lamellar surgery, 85.7% may be considered improved, if cases of chemical burns and heavily vascularised opacities are excluded. Surgery in chemical burns rarely succeeds even with β radiation and Thio-Tepa.
Regrafting is a practical proposition. We have done it upto four times in one eye. 22 penetrating regrafts have resulted in clear grafts in 31.7% of cases.
Uncertainties in this surgery will remain as in any transplantation surgery, but the satisfaction of rehabilitating a blind person should outweigh all pessimism. The 6½ lacs corneally blind people in India should encourage many more eye surgeons to become skilled corneal carpenters. We have had more than our share of encouragement from the confidence which eye surgeons from remote corners of India have placed in us, a confidence which has continued unshaken even in our failures.
| Acknowledgement|| |
Development of this corneal surgery Unit and Regional Eye-Bank, M. G. M. Medical College, Indore to a respectable status is due to the deep interest of Government of Madhya Pradesh, support of Director of Health Services, the encouragement by the Dean and the Superintendent of the Hospital and the co-operation of colleagues and the paramedical staff of the M. Y. Hospital, The Chief Anaesthetist Dr. W. P. Thatte has been an invaluable colleague in this surgery.
The Indian Council of Medical Research by their continued support and the National Council to Combat Blindness, Inc. New York by their substantial grants-in-aid utilised through the help of UNICEF and CARE have helped in enquipping this Unit to a high standard.
| References|| |
Dhanda, R. P. 1961 J. All India Ophthal. Soc. 10:43-50
Dhanda, R. P. 1963 Am. J. Ophth. 55:1217-1219.
King, J. H. 1963 Trans. Am. Acad. Ophthal. & Oto. 67:292-319.
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6]
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6], [Table - 7]