|Year : 1998 | Volume
| Issue : 3 | Page : 149-152
Causes of corneal graft failure in India
L Dandona, TJ Naduvilath, M Janarthanan, GN Rao
Public Health Ophthalmology Service, L.V. Prasad Eye Institute, Hyderabad, India
Public Health Ophthalmology Service, L.V. Prasad Eye Institute, Hyderabad
Source of Support: None, Conflict of Interest: None
The success of corneal grafting in visual rehabilitation of the corneal blind in India depends on survival of the grafts. Understanding the causes of graft failure may help reduce the risk of failure. We studied these causes in a series of 638 graft failures at our institution. Multivariate logistic regression analysis was used to evaluate the association of particular causes of graft failure with indications for grafting, socioeconomic status, age, sex, host corneal vascularization, donor corneal quality, and experience of surgeon. The major causes of graft failure were allograft rejection (29.2%), increased intraocular pressure (16.9%), infection excluding endophthalmitis (15.4%), and surface problems (12.7%). The odds of infection causing graft failure were significantly higher in patients of lower socioeconomic status (odds ratio 2.45, 95% CI 1.45-4.15). Surface problems as a cause of graft failure was significantly associated with grafts done for corneal scarring or for regrafts (odds ratio 3.36, 95% CI 1.80-6.30). Increased intraocular pressure as a cause of graft failure had significant association with grafts done for aphakic or pseudophakic bullous keratopathy, congenital conditions or glaucoma, or regrafts (odds ratio 2.19, 95% CI 1.25-3.84). Corneal dystrophy was the indication for grafting in 12 of the 13 cases of graft failure due to recurrence of host disease. Surface problems, increased intraocular pressure, and infection are modifiable risk factors that are more likely to cause graft failure in certain categories of patients in India. Knowledge about these associations can be helpful in looking for and aggressively treating these modifiable risk factors in the at-risk categories of corneal graft patients. This can possibly reduce the chance of graft failure.
Keywords: Corneal graft, failure, causes, risk factors, India
|How to cite this article:|
Dandona L, Naduvilath T J, Janarthanan M, Rao G N. Causes of corneal graft failure in India. Indian J Ophthalmol 1998;46:149-52
Corneal blindness is a significant public health problem in India., Though preventive strategies may reduce future corneal blindness, the only hope of visual recovery for those currently blind due to corneal diseases may be corneal grafting. The proportion of corneal blind who could derive long-term benefit from corneal grafting depends on the survival rate of the grafts. We have previously reported the indications and survival analysis in a large series of corneal grafts done at our institution. This report examines the causes of 638 cases of corneal graft failure in our series. An attempt is made to identify modifiable risk factors for graft failure with the hope that this knowledge might help efforts aimed at decreasing the risk of graft failure.
| Materials and Methods|| |
The records for a series of 1,964 corneal grafts (penetrating keratoplasties) done at the L.V. Prasad Eye Institute, Hyderabad during 1987-95 were reviewed. Details of the indications for these 1,964 grafts have been described elsewhere. Survival analysis of 1,725 of these grafts, excluding 239 grafts done for active infectious keratitis, has also been reported.
The corneal graft was considered to have failed if it did not retain optical clarity and therapeutic attempts to improve this had no impact, or if there was severe astigmatism that could not be optically corrected, resulting in recommendation of a regraft. Causes of graft failure were categorised as shown in [Table - 1]. Allograft rejection was diagnosed if there were signs of a rejection episode, including epithelial and endothelial rejection lines, subepithelial infiltrates, keratic precipitates, and graft edema.[5-8] Primary graft failure was diagnosed if the graft continued to be cloudy due to diffuse edema from the first postoperative day, and no secondary cause of graft failure could be identified.Endothelial decompensation was diagnosed if the graft became cloudy due to diffuse edema after being clear initially, and no signs of allograft rejection or increased intraocular pressure were present.
The association of particular causes of graft failure with indications for grafting, socioeconomic status, age, sex, host corneal vascularization, donor corneal quality, and whether graft was done by the surgeon during or after fellowship training, was assessed first with univariate analysis, followed by multivariate logistic regression analysis. Patients who are assessed as not having the ability to pay for services at our institution are provided services at no cost to them. These patients were considered as having lower socioeconomic status. Patients were divided into two age groups, ≤10 and >10 years, based on our previous observation that the graft survival was different in these two age groups. Also based on our previous finding that deep and superficial vascularization considered together influenced graft survival, this categorisation was used for the present analysis. Our analysis of the influence of donor cornea grade has shown that the graft survival is different if fair quality donor cornea is used as compared with excellent, very good or good donor corneas considered together. This same categorisation, based on standardised slitlamp evaluation of the donor cornea, was used for the current analysis.
If the grafts in both eyes of a patient had failed, only one randomly chosen eye was included in the multivariate analysis since the outcome in the two eyes of the same patient may be correlated. For the same reason, when multiple graft failures occurred in an eye, only the first regraft failure was included in the multivariate analysis. Odds ratios were determined for the association of causes of graft failure with the variables studied. 95% confidence intervals were calculated to assess statistical significance.
| Results|| |
Graft failure occurred in 638 cases over a maximum follow up of 8 years. The distribution of the causes of graft failure is shown in [Table - 1].
Initial univariate analysis revealed that the proportion of graft failures due to surface problems was higher in grafts done for corneal scarring and previous graft failure than for the other indications. Therefore, corneal scarring and previous graft failure were considered together in the multivariate analysis when evaluating the association with surface problems. For the same reason, graft failures for aphakic and pseudophakic bullous keratopathy, miscellaneous causes including congenital conditions and glaucoma, and previous graft failure were considered together in the multivariate analysis to determine the association with increased intraocular pressure.
In the multivariate analysis, which adjusts for the effect of other variables when evaluating the effect of a particular variable on the outcome, only certain indications for grafting and the socioeconomic status had significant association with particular causes of graft failure. These significant associations are shown in [Table - 2]. Of the 13 cases of graft failure due to recurrence of disease, in 12 cases the indication for grafting was corneal dystrophy. This association did not reach statistical significance in the multivariate model used because of the small numbers. With univariate analysis, the odds of recurrence of host disease as being the cause of graft failure were significantly higher if the graft was done for corneal dystrophy than for the other indications (odds ratio 160, 95% CI 20-1311, p<0.001).
| Discussion|| |
Various strategies are needed to deal with corneal blindness in India. Effective strategies to prevent corneal blindness from occurring require a comprehensive eye-care approach. This is necessary in the long term, though this approach will take some time to be implemented on a large scale in India. Such community-based comprehensive eye-care programs are being conducted in the West Godavari and Adilabad districts of the Indian state of Andhra Pradesh, by the L.V. Prasad Eye Institute, details of which can be obtained from the authors. However, in order to deal with the current level of corneal blindness in India, approaches are needed to make visual rehabilitation feasible in as large a number of these blind as possible. One way to do this is to better understand which patients have a more favourable prognosis for graft survival and visual outcome in the Indian setting, which would help in more effective utilisation of the limited number of donor corneas available. In addition, if associations of modifiable risk factors for graft failure with certain categories of patients are identified in our setting, these could be looked for and treated aggressively in an attempt to reduce the occurrence of graft failure. The present paper evaluates these associations in a large series of corneal grafts in India.
Our analysis revealed three modifiable risk factors for corneal graft failure which were associated with certain categories of patients. Graft failure due to surface problems was significantly associated with grafts done for corneal scarring or previous graft failure. Increased intraocular pressure accounted for a significantly higher proportion of graft failures amongst aphakic and pseudophakic bullous keratopathy, congenital conditions and glaucoma, and previous graft failure than amongst corneal scarring, dystrophies, and keratoconus. Infection as a cause of graft failure was significantly associated with lower socioeconomic status. Surface problems and increased intraocular pressure as causes of graft failure are potentially modifiable risk factors. If particular attention is paid to looking for the presence of these factors in the at-risk categories of corneal graft patients, and treatment is pursued aggressively, it may be possible to reduce the chance of graft failure. The association of infection as cause of graft failure with patients belonging to the lower socioeconomic status is a complex phenomenon. Predisposition of this category of patients to infection is probably related to the surroundings in which they can afford to live in. If adequate emphasis is laid on explaining to this category of patients the need for maintaining good hygiene for the success of their corneal graft, perhaps, the chance of graft failure due to infection may be reduced.
Since significant association was found between some indications for corneal grafting and causes of graft failure in our analysis, and the distribution of indications for grafting are different in India than in the developed world, direct comparison between the causes of graft failure in a large series in India with those reported from the developed world may not be valid.
The information reported in this paper, along with that reported earlier about corneal graft survival analysis, may help increase the success rate of corneal grafting in India. Concurrently, the vital issues of quality eye banking to increase availability of donor corneas and training of adequate corneal surgeons to meet the need in India have to be addressed in order to deal with corneal blindness effectively. In the long-term, however, prevention of corneal blindness with effective public health strategies may be more cost-effective.
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[Table - 1], [Table - 2]