Processing of the Donor Tissue
Collection of Cornea
Removal of cornea from a dead body is known as Enucleation. When an enucleation / donation call is received from the donor family by our counselor, following details are collected from the informant:
- Name, age, sex of the deceased person (donor)
- Cause & time of death
- Death occurred in the hospital or at home
- Home address and nearest landmark
- Informants name and phone number
A EBSR technician immediately starts to procure the cornea from the donor.
The cornea is enucleated by standard surgical procedures maintaining aseptic conditions during and after removal of the cornea from eyes. The eyelids are stitched using a black thread. This gives an appearance as if the donor is asleep. There is absolutely no disfigurement of the face after cornea is removed.
After the enucleation, the technician draws 5 ml of blood from the donor to screen for infectious diseases. The enucleated corneas are transported in a special glass bottle with a metal stand termed as Moist Chamber and transported to the Eye Bank for processing and utilisation immediately.
After receipt of the cornea in EBSR Lab, Jaipur the cornea is processed through following, procedure :-
Serology Test :
The blood sample of the donor is put through serology test to check for HIV and Hepatitis B. Only if the serology result is negative, the donor cornea is used for excision.
Evaluation using Slit Lamp :
The cornea is evaluated under the slit lamp .It enables the ophthalmologist / eye bank technicians to study the layers of the cornea individually (Epithelium, Stroma & endothelium) to identity Corneal defects. The slit lamp view helps assess the qualitative strength of the endothelium (the inner layer of the cornea) and decide its utility for Penetrating Keratoplasty, therapeutic use, or for research and training purposes.
Cornea Evaluation under Specular Microscope:
Endothelium is the innermost layer of cornea and is primarily responsible for the quality of the vision after a cornea grafting surgery (PKP). The assessment of the endothelium becomes important to decide the utility of the tissue. The Specular microscopy allows direct high magnification of the endothelial cells and consequently better judgment of its status by counting the number of cells / mm square.
Endothelial cell analysis:
The endothelial cells of the donor cornea can be viewed under a Specular microscope to analyse :
- Cell density - ideally it should be > 2000 (PKP)
- o Hexagonality of the cells which should be more than 50%
Slit Lamp Evaluation:
After excising the cornea, it is superficially evaluated under the slit lamp for grading.
- Excellent
- Very Good
- Good
- Fair
- Not suitable for surgery
After passing through all these tests a tissue is certified as suitable for transplantation by the Medical Director of EBSR.
Documentation:
Maintaining proper track records for the utility of the tissues is very important for Eye Banks to analyze the rate of utility, and to initiate research. The documentation also helps to review our statistics and eye banking mechanism. The documentation will be useful in writing proposals and producing reports to various organizations.
