Reliability of nucleus-to-cell and nucleus-to-cytoplasm calculations for conjunctival impression cytology specimens

The study aim was to assess the outcome of two different nucleo-cytoplasmic ratio calculations in relation to the number of cells measured from conjunctival impression cytology (CIC) images. CIC from the exposed nasal bulbar conjunctiva surface was undertaken on 40 young adults using a Millcell(®)-CM filter; the filters were stained with Giemsa, colour images taken of the cells in a monolayer at 200 X magnification, graded by the Nelson scale and then a projection overlay method used to outline the cell and nucleus borders. Nucleo-cytoplasmic ratios were calculated based on literal interpretation of the term (i.e. N/CYT¿=¿nucleus area/[cell area - nucleus area]) as well as based on cell area (i.e. N/CELL¿=¿nucleus area/cell area).