Tissue artefacts in post mortem human eyes.

Abstract

Purpose : Post mortem donors are the main source of human tissue for eye research. Post mortem artefacts can substantially affect histological interpretation. The study examined the prevalence of macroscopic and microscopic post mortem artefacts in 24 human eyes. The types of artefact and the relationship between donor age, cause of death and post mortem delay to fixation were also examined.

Methods : Twenty four human eyes (14 donors; 9M/5F; age 32-81yrs; mean 66yrs) from the Lions NSW Eye Bank were included in the study. Eyes were fixed in 10% neutral buffered formalin. Standardised ex vivo fundus photographs were independently assessed by at least two ophthalmologists (surgical or medical retina). Eyes were processed for routine histology, paraffin embedded, sectioned and H&E stained. H&E slides were independently assessed by at least two phthalmic pathologists. Post mortem artefacts identified on ex vivo fundus imaging and on histology were documented and correlated to patient age, cause of death and interval between death and formalin fixation.

Results : All study eyes had some retinal detachment and retinal opacification on fundus photography. Histological artefacts included: (i) retinal detachment; (ii) photoreceptor inner and/or outer segment detachment; (iii) vacuolation of nerve fibre and/or ganglion cell layer, with or without schisis; (iv) vacuolation of outer plexiform layer, with or without schisis; (v) detachment of RPE from choroid; (vi) detachment of choroid from sclera; and (vii) inner limiting membrane detachment. Histological artefacts were graded as mild if there were up to two artefacts, moderate if there were three to five artefacts and severe if there were more than five artefacts. Of the 24 eyes, mild histological artefacts were seen in 8 eyes (40%), moderate artefacts in 7 eyes (35%) and severe artefacts in 9 (45%) eyes.There was no relationship between donor age or donor history and severity of histological artefacts. The average post mortem delay to fixation was significantly lower in eyes with mild histological artefacts compared to eyes with severe histological artefacts (11.44 vs 19.25hrs; 95% CI 1.82-13.81hrs; p = 0.01).

Conclusions : Artefacts were seen in all post mortem donor eye tissue. Delay in fixation can significantly affect the severity of post mortem artefacts. Recognition of common post mortem artefacts is critical when evaluating donor human eye tissue for disease-specific changes.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.