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Morphological Screening of Donor Corneal Tissue for Previous Refractive Surgery
Chinh Nguyen, MBBS; Chameen Samarawickrama, MBBS, PhD, Rasik Vajpayee, FRANZCO
refractive surgery, eye banking, corneal tissue, screening, whole globe enucleation, corneoscleral rim
Purpose: A major concern for eye banks internationally is the detection on routine screening of corneas with previous corneal refractive surgery. It is increasingly becoming a concern with the rise in prevalence of refractive surgery in our community and the variety of refractive procedures available. Inadvertent transplantation of corneas with previous refractive surgery can have serious visually significant sequelae varying from unexpected refractive surprises to tectonic compromise. Morphological screening has undergone significant changes as recovery of corneoscleral rims for corneal donation has increased in frequency to the older technique of whole globe enucleation. The current screening protocols, namely using slit lamp biomicroscopy of tissue stored in transport media coupled with a medical history, has been shown to be fallible. To overcome this shortfall, new technology such as specular microscopy, corneal topography and optical coherence tomography have been employed to improve the detection rate of previous corneal refractive surgery. However, there are major limitations that have prevented their widespread use. The newer screening modalities are better suited to screening whole globes rather than corneoscleral rims and for effective utilization the technology has to be compatible with both tissue recovery techniques. No single modality has been shown to be adequate in detecting the full variety of refractive procedures. In addition the technology has to be cost effective for eye banks to incorporate them into their screening protocols. This review summarizes the literature to date on screening techniques currently available and their utility in detecting previous refractive surgery in donor corneas.