A Simple and Reliable Technique to Orient Donor Corneal Tissue Using the Radial Width of the Surgical Limbus.
OBJECTIVE
To develop a method based on identification of the widest region of the surgical limbus that can yield quick and accurate orientation of excised human donor corneas.


METHODS
Corneoscleral tissue from donors 49 to 75 years old was marked at the temporal sclera at the time of recovery. Digital images obtained from 20 corneas stored in viewing chambers, retroilluminated and viewed from the endothelial side, were used to quantify the per-degree radial width of the surgical limbus, defined as the distance from the scleral spur to clear cornea. To evaluate differences in radial width among regions, measurements were compared with the intracorneal mean limbal width, and a per-degree z-score was calculated by averaging among corneas. Using images of corneas with the temporal mark masked and the sidedness known, 6 observers were subjected to a blinded trial of 10 corneas to determine the central point of the widest limbal region of each cornea.


RESULTS
Compared with the intracorneal mean, the mean radial width of the surgical limbus was greatest in the superior quadrant, and the difference compared with the inferior, nasal, and temporal quadrants was significant (P < 0.0001). The superior region was identified with 100% accuracy in blinded trials. The average absolute difference between the predicted and actual central point of the superior limbus was 9.75 ± 0.30 degrees.


CONCLUSIONS
The radial width of the surgical limbus is greatest in the superior region of the cornea and can be used as a diagnostic feature to orient donor corneal tissue.
* Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, IA; †Iowa Lions Eye Bank, Coralville, IA; ‡Department of Biostatistics, University of Iowa College of Public Health, Iowa City, IA; and §Cornea Research Center, Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, IA.
Benjamin T
BT
Aldrich
Adam M
AM
Stockman
Monica J
MJ
Freiburger
Todd J
TJ
Shinkunas
Kimberlee A
KA
Burckart
Gregory A
GA
Schmidt
Cynthia R
CR
Reed
M Bridget
MB
Zimmerman
Kenneth M
KM
Goins
Michael D
MD
Wagoner
Mark A
MA
Greiner
D000368:Aged; D059925:Anatomic Landmarks; D003315:Cornea; D005125:Eye Banks; D006801:Humans; D016850:Limbus Corneae / Q000033:anatomy & histology* / Q000601:surgery; D008875:Middle Aged; D014019:Tissue Donors; D020858:Tissue and Organ Harvesting / Q000379:methods*