|Year : 1984 | Volume
| Issue : 5 | Page : 441-446
Keratoplasty in alkali burned corneas
Anita Panda, Madan Mohan, AK Gupta, S Chawdhary
Dr. Rajendra Prasad Centre for Ophthalmic Sciences AIIMS, Ansari Nagar, New Delhi, India
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, Ansari Nagar, New Delhi-110 029.
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Panda A, Mohan M, Gupta A K, Chawdhary S. Keratoplasty in alkali burned corneas. Indian J Ophthalmol 1984;32:441-6
|How to cite this URL:|
Panda A, Mohan M, Gupta A K, Chawdhary S. Keratoplasty in alkali burned corneas. Indian J Ophthalmol [serial online] 1984 [cited 2021 Oct 21];32:441-6. Available from: https://www.ijo.in/text.asp?1984/32/5/441/27536
Despite the quick and deep penetration, the ocular damage by alkali burns is restricted to the anterior segment of the eye. The posterior segment can be saved if the complications caused by the anterior segment involvement can be checked. Corneal transplantation for severely alkali burned corneas frequently fails and is, therefore, contraindicted.
The results of keratoplasty in sixteen eyes with alkali burned corneas is analysed. A classification of severely alkali burned corneas, requiring keratoplasty, is suggested. This classification has therapeutic and prognostic value.
| Materials and methods|| |
Sixteen eyes with healed alkali burns received corneal transplants. The eyes were particularly examined for the presence of lid abnormalities, dry eyes, cataract, glaucoma and posterior segment abnormalities, prior to keratoplasty. Depending upon the depth of corneal opacity, extent of corneal vascularization and pseudopterygium these eyes were graded into mild, moderate severe and very severe groups. [Table - 1], [Figure - 1][Figure - 2][Figure - 3][Figure - 4].
The three eyes in the mild group had received lamellar corneal transplants. The four eyes with moderate involvement had received penetrating corneal grafts. One of these eyes had a cataract extraction during the post operative follow up period [Figure - 5]. Two of the eyes in the severe group received lamellar grafts. In both of these, penetrating keratoplasty was done later. The other four eyes in this group received penetrating corneal grafts and in three of these a repeatpenetraLing graft had to be put, alongwith trabeculectomy in three cases and lens extraction in one case. In the severe group one eye had received a lamellar graft and two eyes. had received penetrating grafts. Two of these had a repeat penetrating graft in the follow up period.
The pseudopterygium was dissected alongwith the superficial corneal lamellae and recessed beyond the limbus by Mohans technique 2(Mohan et al 1976).
| Observations|| |
Of the three eyes in the mild group two had a clear graft and one had a partially clear graft. The eye had mild vascularization of the cornea [Table - 2] and [Figure - 6].
Of the four eyes in the moderate group two remained clear, one partially clear and the remaining one became opaque. [Table - 3].
Both the lamellar grafts in the severe group became opaque and were followed by penetrating keratoplasty of which one remained clear and the other was partially clear. Of the four full thickness grafts in this group three became opaque and one was partially clear. On repeating penetrating keratoplasty in these three cases the graft remained clear in one case only. In one case post operative endopnthalmitis developed. [Table - 4].
Of the two eyes in the very severe group, one developed atrophic bulbi and the other one had a repeat penetrating keratoplasty combined with trabeculectomy but the graft became totally opaque. The third eye in this group developed ulceration of the lamellar graft [Figure - 7] and a therapeutic keratoplasty was done. The eye, however, went into atrophic bulbi [Table - 5], [Figure - 8].
| Discussion|| |
Based on the results of keratoplasty in sixteen eyes with healed alkali burns a classification for grading these lesions is suggested. It is suggested that the eyes with mild involvement of the cornea should undergo, lamellar corneal grafting. Eyes with moderate- corneal involvement should have a penetrating corneal graft. In the severe grades, the results of keratoplasty, both lamellar and penetrating were uniformly bad. However, following a repeat keratoplasty there was an overall graft clarity in 66% of the cases. Hence keeping this in view and the relatively increased incidence of complications in penetrating keratoplasty as a primary procedure, a preparatory lamellar corneal grafting followed by a penetrating keratoplasty would be expected to yield better results. Where the corneal involvement is very severe, the added factors of cataract, glaucoma, tear film abnormalities and lid abnormalities are also invariably present in varying proportions. The results of kerato- , plasty in these cases is very bad. Repeat corneal grafts also become opaque in these cases. Keratoprosthesis could be of some use in these cases and encouraging results have been reported. This however, needs further evaluation.
Why should another classification for alkali burned corneas be suggested? The classification of alkali burns of cornea was put forward by Ballen in which grading was based on epithelial involvement, stromal haze, conjunctival congestion, chemosis and necrosis. It was experienced that conjunctival congestion and chemosis were not very important factors in the visual prognosis of these cases and therefore Roper Hall, modified the Ballen's classification in which ischemia at the limbus was retained whereas conjunctival congestion chemosis and necrosis were eliminated. The modified Roper Hall classification is good as far as acute lesions are concerned, however this is of no use in corneas with healed lesions of alkali burns that require surgical intervention. Predominently the grade three and four lesions, by the modified Roper Hall classification, proceed to heal with opacities that would require surgical intervention. The modified Roper Hall classification is based on the depth of the epithelial damage. corneal haze and limbal ischemia. In the healed lesions none of these parameters are found. The present classification therefore is based on the depth of corneal opacity. and the extent of corneal neovascularisation, pseudopterigium and symblepharon. The other factors that many a time present in healed alkali burns ie. lid abnormalities-entropion, ectropion and trichiasis, tear film abnormalities, induced by the involvement of both the lacrimal gland duct and the conjunctival goblet cells secondary glaucoma, cataract and iritis. Presence any of these factors further worsens the prognosis by one grade. This classification is therefore useful in indicating the preferred type of keratoplasty and giving the prognosis in a given case. A better comparison of the various reports can be made since there are differences in the distribution of cases in the various grades in different series.
Any of the bad prognostic factors if present need separate treatment. The lid abnormalities need seperate lid plasty prior to keratoplasty. Pseudopterygium if present should be recessed along with the superficial corneal lamellae upto the limbus. The advantages of this technique over the usual resection off the pseudopterygium are that by recession there is relaxation of the contractures and symblepharon and addition of tissue, which aids in free eye movement and eliminates post operative diplopia. Signs of healed iritis are almost always present and the surgery should, therefore, be done under the cover of steroids. The cataract when present should be operated upon along with keratoplasty. The lenticular opacities invariably increase after the keratoplasty. Lens extraction in a grafted eye decreases the graft clarity.
The association of secondary glaucoma in these cases is frequent, especially after the first graft has become opaque. A filtering surgery at the time of keratoplasty improves the prognosis for clarity as well as post operative vision. Artificial tears are most useful in cases with tear film abnormalities. Surgical measures like the transplantation of the Stepsons duct and closure of the puncta are not very useful in these cases.
Post operatively the use of bandage soft contact lenses and anticollagenases have a beneficial role especially when the graft develops an ulcer., The soft contact lenses require expert handling by a contact lens specialist and frequent changes. This coupled with the nonavailability of anticollagenases in India may be of particular practical importance at some of the places.
The ultimate visual prognosis is dependent upon the graft clarity and the absence of pathology in the posterior segment. Preoperative inaccurate projection of light rays, raised intraocular pressure and defective pupillary reaction are bad prognostic factors for the post operative vision. Evaluation of posterior segment by ultrasonography should be done in all cases. Laser inferometery would be very useful in giving visual prognosis preoperatively.
Results of keratoplasty in alkali burned corneas have been reported to be bad by most of the authors,, However Brown et al, reported 66% success in these cases. The overall results in the present series are 62% and are quite encouraging. The increasing use of surgical microscope and better suture material is partly responsible for improved results. Selection of appropriate type of therapeutic modality on the basis of the grading of these lesion may further improve the graft prognosis.
| Summary|| |
Results of keratoplasty in sixteen eyes with severely alkal burned corneas are analysed. A classification for grading the healed lesion in eyes with severe alkali bums is suggested. This classification is useful in deciding the .type of keratoplasty and knowing the prognosis.
| References|| |
Girard LG., Alford W.E., Fieldman G.L. and William B., 1970. Trans Amer. Acad. Ophthalmol & Otolaryngol 74: 788.
Mohan M., 1976. Proceedings of the 6th Afro Asian Congress of Ophthalmology.
Ballen B., -1963. Am. Jr. Ophthalmol. 59: 674.
Roper Hall MI, 1965. Tr. Ophthalmol. Soc. U.K. 85: 631.
Brown S.I., Michael P.T. and David B.P., 1972. Trans Amer. Acad. Ophthalmol & Otolaryngol, 76: 1266.
Lemp A.M., 1974. A.M.A. Arch. Ophthalmol. 92. 158.
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8]
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6]