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Processing of the Donor Tissue
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Eye Ball Collection (Enucleation) |
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Removal of eye balls from a dead body is known as Enucleation.
When an enucleation call is received from the donor family, the following details are collected from the informant:
1. Name, age, sex of the deceased person (donor)
2. Cause & time of death
3. Death occurred in the hospital or at home
4. home address and nearest landmark
5. Informant’s name and phone number
A team of physicians and paramedics numbering 3 to 4 members set to attend the enucleation call.
The eyes are removed by standard surgical procedures maintaining aseptic conditions during and after removal of the eyes. After the eyes have been removed, a ball of cotton wool is tightly packed in the empty eye socket or artificial eye balls are placed inside. The eye lids 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 eyes are removed.
After the enucleation, the Physician draws 5 ml of blood from the donor to screen for infectious diseases. The enucleated eye balls are transported in a special glass bottle with a metal stand termed as Moist Chamber and transported to the Eye Bank for processing and utility. |
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Serology Test : |
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After the enucleation of the eye from the donor, 5 ml of blood is withdrawn from the deceased body to check for infectious diseases. The serum from the blood of the donor is checked for HIV and Hepatitis B. Only if the serology result is negative the donor cornea is used for excision |
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Evaluation using Slit Lamp : |
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The corneal globe is evaluated under the slit lamp .It enables the Ophthalmologist / eye bank technicians to study the layers of the cornea individually (Epithelium, Stroma & endothelium). Corneal defects can be identified. The slit lamp view could help to assess the qualitative strength of the endothelium (the inner layer of the cornea) and decide its utility for Penetrating Keratoplasty / Therapeutic / Research / Training. |
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Excision of the Cornea: |
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The cornea is cut under aseptic medium and separated from the eyeball and stored in a suitable MK medium (Mc Carey Kaufman’s medium). Under this medium cornea could be stored for about 3-4 days. The time gap between death and cornea preservation in our country (based on the climatic condition) SHOULD NOT EXCEED 6 to 7 hours failing which the quality of the cornea is not suitable for optical penetrating Keratoplasty (surgery for restoring vision). |
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Cornea Evaluation under Keratoanalyser / Specular Microscope: |
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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 |
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Slit Lamp Evaluation:
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Before excising the cornea, The Eye ball is superficially evaluated under the slit lamp for grading.
- Excellent
- Very Good
- Good
- Fair
- Not suitable for surgery
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Endothelial cell analysis: |
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The endothelial cells of the donor cornea can be viewed under a Specular microscopy to analyse its:
- Cell density - ideally it should be > 2000 (PKP)
- Hexagonality of the cells should be more 50%
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Documentation: |
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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 produce reports to various organizations.
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