**1. Introduction**

The cornea is normally a clear layer of tissue covering the front of the eye, similar to a watch crystal. Its purpose is to refract or bend light rays as they enter the eye, allowing them to focus on the retina (1, 2).

Corneal diseases are a significant cause of visual impairment and blindness in the developing world [3] Penetrating keratoplasty (PK) offers hope for visual rehabilitation in many such cases (3).

Corneal transplantation, also known as corneal grafting or penetrating keratoplasty, is a surgical procedure where a damaged or diseased cornea is replaced by donated corneal tissue which has been removed from a recently deceased individual having no known diseases which might affect the viability of the donated tissue (1, 4). Corneal transplantation has two major types, penetrating keratoplasty (P.K) in which the full thickness of cornea is replaced and lamellar keratoplasty (L.K) in which a portion of cornea is replaced. The term PK commonly refers to surgical replacement of a portion of the corneal with that of a donor eye. LK surgery consists of placing a partial thickness donor corneal graft in a recipient corneal bed that is prepared by lamellar dissection of diseased anterior stoma corneal tissue (5, 6).

In Worldwide, Corneal transplant is one of the most common transplant procedures although approximately 100,000 procedures are performed each year; some estimates report that 10,000,000 people are affected by various disorders that would benefit from corneal transplantation. In some situations such as scar, edema, thinning and severe distortion there is no treatment other than corneal transplantation (7, 8).

The decline of certain disorders due to changes in surgical practice, and the emergence of new surgical techniques have largely influenced the changing trend. The indications for PK have continued to change since 1940 (9-10), and investigators have studied the changing trends over the past few decades (9-13).

Indications for corneal transplantation include the following:

Clinical Indications for Penetrating Keratoplasty and

males was 51/3±21.5 and for women was 57/2±19/1. (P=0.26)

group in compared with average age of urban patients group. (p=0.001).

Table 1. Evaluation of indication cause of keratoplasty in Job groups

**3. Result** 

(Table1).

Epidemiological Study in Teaching Hospitals of Birjand Medical University from 1999 to 2006 5

A total of 120 patients underwent PK operations during the 7-year study period. From 120 patients; 86(71/66%) were male and 34(28/33%) were female. The mean patient's age was 53 years with a standard deviation (SD) of 20.9 and a median of 59 years. The mean age of

And also, the average age of rural patients was 61± 17.4 and urban patients were 42.7 ± 20.7, in statistically, there is a significantly difference between the average age of rural patients

The main indications cause keratoplasty were corneal locuma 75(62.5%), keratoconus 23(19.16%) and others (Bolus keratopaty + corneal dystrophy) 22(18.34%). (p=0.001)

**Job Groups corneal locum keratoconus The else 1) Farmers-animal husbandman** 29(76%) --------------- 9(24%)

**2) Simple worker -Artisan** 7(71.4%) 2(18.18%) 2 (18.18%) **3) Staff-Driver-carpet weaver** 12(66.66%) 4(22.22%) 2(11.11%) **4) Housewife-Not busy** 25(68%) 4(11.11%) 7(19.44%) **5) Students** 2(9.1%) 13(76.47%) 2(11.76%) **Total** 75(62.5%) 23(19.16%) 22(18.34%)

*Optical*: To improve visual acuity by replacing the opaque or distorted host tissue by clear healthy donor tissue. The most common indication in this category is pseudophakic bullous keratopathy, followed by keratoconus, corneal degeneration, keratoglobus and dystrophy, as well as scarring due to keratitis and trauma.

*Tectonic/reconstructive*: To preserve corneal anatomy and integrity in patients with stromal thinning and descemetoceles, or to reconstruct the anatomy of the eye, e.g. after corneal perforation.

*Therapeutic*: To remove inflamed corneal tissue unresponsive to treatment by antibiotics or anti-virals.

*Cosmetic*: To improve the appearance of patients with corneal scars that have given a whitish or opaque hue to the cornea.

To update these trends and also to provide information for the prevention of corneal blindness we report the indication causes for penetrating keratoplasty (PK) in Teaching Hospitals of Medical Birjand University from 1999 to 2006.
