K. Blades et al., PILOT-STUDY ON THE USE OF IMPRESSION CYTOLOGY SPECIMENS FOR QUANTITATIVE ASSESSMENT OF THE SURFACE-AREA OF BULBAR CONJUNCTIVAL CELLS, Optometry and vision science, 75(8), 1998, pp. 591-599
Purpose. To assess whether impression cytology samples could be used t
o assess cell conjunctival cell surface areas, and to obtain an estima
te of these for normal appearing cells vs. those with squamous metapla
sia, Methods. Small sheets of nasal bulbar conjunctival cells (c. 0.03
mm(2)) were obtained from 17 subjects aged 25 to 78 years by manual a
pplication of a 0.45 mu m Millipore filter without topical anesthetic.
Outlines of cells, visible as a rarefaction of the general cell cytop
lasmic staining, were made on an optical overlay and then planimetry w
as carried out. Results. Reasonable estimates (with +/-2.5%) of the av
erage cell area can be obtained from samples containing contiguous set
s of 100 cells. From 14 separate samples of normal cells [subjective a
ssignment of nucleus:cytoplasm (N:C) ratios of 1:1 to 1:2], cell surfa
ce area values ranged from 11 to 426 mu m(2), with an overall average
value of 108 +/- 43 mu m(2). Samples from individuals with symptoms su
ggestive of borderline dry eye tended to have slightly higher proporti
ons of larger cells (so increasing the average cell area), and there w
as a trend for samples from older individuals to contain more smaller
cells (so decreasing the average cell area). In marked contrast, cells
showing evidence of squamous metaplasia and with N:C ratios of 1:6 or
higher were found to have an average area of 543 +/- 76 mu m(2) (rang
e 310 to 1529 mu m(2)). Conclusions. Morphometry of impression cytolog
y specimens is possible. The average cell size in normal individuals i
s considerably smaller than previously reported (108 vs. 585 mu m(2)),
but this is consistent with a range of studies on animal tissue using
scanning electron microscopy.