Blindness is a significant public health problem in developing countries. Cataracts and corneal diseases are the two major causes of blindness in countries in developing economies. [1]. According to the World Health Organization, corneal diseases are one of the significant causes of vision loss and blindness in the world today, after cataracts and glaucoma. [2].

In India, it is estimated that there are approximately 6.8 million people with vision less than 6/60 in at least one eye due to corneal diseases; out of these, about a million have bilateral involvement. [3,4]. It is estimated that the number of people with unilateral corneal blindness in India will increase to 10.6 million by 2020. [4].

According to the National Programme for Control of Blindness (NPCB) estimates, about 120,000 corneal blind persons in the country. According to a recent estimate, there is an addition of 25,000-30,000 corneal blindness cases every year in the country. [5]. The burden of corneal disease in India is reflected by 90% of the global cases of ocular trauma, and corneal ulceration leading to corneal blindness occur in developing countries. [6].

The importance of corneal transplant lies in the fact that successful transplantation can restore excellent sight to corneal blindness. Penetrating Keratoplasty is the most frequently performed and the most successful form of transplantation. [7]. The proportion of corneal blind patients who could derive long term benefits from corneal grafting depends on the graft transparency. Trans­parency is affected by many factors.

These factors are the type of donor material, condition of the recipient's eye, the operative procedures and postoperative treatment. The quality of donor material depends upon the donor's age, cause of death, the interval between the time of death and time of enucleation, the duration for which the donor's eye was preserved, the clinical condition of the donor's vision, its bacteriological and method of preservation and endothelial cell count.

The function of Endothelial cells of the cornea maintains this tissue in a dehydrated state by their pumping activity, assuring its transparency. The corneal endothelium consists of a single layer of non-regenerating, mainly hexagonal cells.

There was a total of 30 patients in our study. Clinical observations were made to study the factors affecting the clarity of the graft.

Table 1: Demographic profile

The youngest patient was 11 years old, and the most geriatric patient was 90 years old. The mean age was 39.73 years. There were 23 males and seven females.

Graft clarity: We studied 30 patients for graft clarity. Among them, 18 patients (60 %) had clear corneas, and 12 patients (40%) had graft failure after six months of follow up.

Table 2- Endothelial cell count and graft clarity

This table shows the relationship between Endothelial cell count and graft clarity. The mean endothelial cell count in group 1(opaque graft) was 1942.3/mm^2, and group 2 (clear grafts) was 2334.8/mm². There is a significant difference in the mean endothelial cell count between the two groups.

Figure 3– Indications of Keratoplasty and graft clarity

On analysing the indication for Keratoplasty in two groups, the outcome was best for the corneal opacity group during worst for the graft failure group.

This figure shows the relationship between corneal pathology and graft clarity. The adherent leucoma group patients showed one clear graft (3.3%) and two hazy grafts (6.6%). In the Pseudophakic Bullous Keratopathy group, patients 3(10%) had clear grafts, and one (3.3%) had hazy cornea. For patients of the previous graft failure group, only 1 (3.3%) had clear grafts, while six patients (20%) had hazy grafts. The outcome was best for the corneal opacity group during worst for the previous graft failure group.

In our study, we analysed various donor and recipients' factors affecting graft clarity. However, immunologic graft rejection after Keratoplasty is less likely than it is in other solid organ transplantation. This is attributable to the avascular corneal structure, the immunosuppressive ocular microenvironment, and the phenomenon of the anterior chamber–associated immune deviation. This produces reduced immunity to antigens introduced into the anterior chamber in experimental animal models.8,9 However, in eyes presenting with corneal neovascularisation and previous graft failure, the prognosis for corneal graft survival is reduced, and the incidence of rejection is high, similar to that of solid organ transplants. In our study, we found 60% of grafts to be precise.

Correlation between endothelial cell count and graft clarity

In our study, we found that endothelial cell count has a significant effect on graft transparency.

Endothelial cells of the human cornea maintain this tissue dehydrated by their pumping activity, thereby assuring its transparency. This is an active process that is controlled by Na⁺/K⁺ ATPase and involves the generation of a bicarbonate ion gradient across the corneal endothelium. The corneal endothelium consists of a monolayer of polygonal cells, the numerical density of which is highest at birth (3000 cells/mm²) and decline slowly but steadily after that.

Based on the observations of the Australian Graft Registry, some grafts are categorised as high-risk grafts [14].

• Indications of graft other than keratoconus or corneal dystrophies
• Previously failed ipsilateral graft
• Aphakia
• Inflammation at the time of P.K.
• Presence of ACIOL or iris-claw IOL
• Graft size more than 7.9mm
• Pre- or Post-operative corneal vascularization

Our findings are in complete agreement with these workers that corneal opacity without vascularisation is a good indication for performing Keratoplasty.

In our study, corneal opacity group, all patients had clear graft, while the results were worst for the graft failure group.

Our study is one of its kind as it compares mean endothelial cell count with graft clarity.

Donor endothelial cell count significantly influenced graft outcome; rest donor factors like age, death enucleation interval, enucleation surgery interval don't affect graft survival.

Indication for Keratoplasty is a significant predictor of graft survival. The outcome was best for the corneal opacity group during worst for the graft failure group.

AJ: Concept of study, Review of literature.

HJ: Data collections and its interpretation.

NJ: Data management, references, and literature review.