Abstract
Purpose:
Ocular Surface Conjunctival Impression Cytology (OSIC) is a routinely used investigation, but effective reproducible cellular sampling is difficult. The EyePRIM is a single-use polyethersulphone (PES) supor filter mounted in a device designed for OSIC. Our aim was to compare the efficiency, patient tolerability and efficacy of sampling with the EyePRIM and with standard PES Supor filters for analysis by flow cytometry,
Methods:
One EyePRIM was used to impression the lateral bulbar conjunctiva and a second, the medial bulbar conjunctiva of the same eye giving a total impressioned area of 138mm2 (n=3 donors). Two Supor 200 PES circular filters (total area 264mm2) were bisected and OSIC was performed using one semi-circle in each quadrant of the contralateral bulbar conjunctiva. All filters were placed in RPMI 1640 medium supplemented with 10% heat-inactivated fetal calf serum. The time taken for sampling was recorded, together with a subjective assessment of discomfort during sampling using a 10cm Visual Analogue Score (VAS). Cells were recovered from both the EyePrim and PES Supor filters using gentle agitation with a pipette tip for one minute, and stained with antibody markers for leukocytes (CD45), CD16, EpCAM, HLA-DR and a dead cell exclusion dye. To enable comparison of event counts between samples, 5µl of counting beads were added to each sample. Cells were recovered from both the EyePrim and PES Supor filters using gentle agitation with a pipette tip for one minute, and then stained with antibody markers for leukocytes (CD45), CD16, EpCAM, HLA-DR and a dead cell exclusion dye. To enable comparison of event counts between samples, 5µl of counting beads were added to each sample.
Results:
The mean corrected total event counts for the EyePRIM was greater than for the Supor PES filters (475,544 events versus 335,226 events) as was the mean corrected CD45+ events (879 versus 372) although this did not reach statistical significance. Patient tolerability was comparable with an average VAS for the EyePRIM of 0.3cm versus Supor PES filters of 0.7cm (p=0.125). The mean time taken to sample one eye was less for the two EyePRIMS versus four Supor PES semicircles (110 and 177 secs respectively).
Conclusions:
The EyePRIM is quick, well tolerated and can be used for reliable impression cytology. The device is efficient to use, with a similar cellular yield despite sampling a 50% smaller ocular surface area.
Keywords: 474 conjunctiva •
468 clinical research methodology