A noncontact pneumatic esthesiometer for measurement of ocular sensitivity: a preliminary report.
OBJECTIVE
The aim of this investigation was to evaluate a prototype noncontact pneumatic esthesiometer for measuring sensitivity of the eye.


METHODS
To evaluate the instrument's repeatability, central corneal sensitivity was recorded on two separate occasions with a 24-h interval between the two measures. In a separate experiment, corneal edema was induced with a thick hydrogel lens, and the eye was closed and patched. Corneal sensitivity was measured before wearing the lenses for 3 h, immediately after lens removal, and 15 min later. Corneal sensitivity also was measured before the instillation of a single drop of proparacaine (Alcaine, 0.5%) and at 2 and 18 min later. Sensitivity was measured at the corneal apex and at a temporal conjunctival location 3 mm from the limbus.


RESULTS
A high correlation was found between days 1 and 2 (r = 0.90; p = 0.0001). The coefficient of repeatability (COR = 0.87 mm Hg) showed that 95% of the difference between test and retest measures were between +/-0.87 mm Hg. Corneal sensitivity decreased by 55% after lens-induced corneal swelling and by 159% after instillation of the topical anesthetic. Central corneal sensitivity was found to be significantly higher than that of the temporal conjunctiva (p = 0.0001).


CONCLUSIONS
We conclude that this pneumatic esthesiometer provides repeatable and reliable measures of ocular-surface sensitivity.
Vega
J A
JA
Centre for Contact Lens Research, School of Optometry, University of Waterloo, Ontario, Canada.
Simpson
T L
TL
Fonn
D
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000779:Anesthetics, Local / Q000494:pharmacology; D003263:Contact Lenses, Hydrophilic; D003315:Cornea / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D015715:Corneal Edema / Q000209:etiology / Q000503:physiopathology; D004867:Equipment Design; D004864:Equipment and Supplies; D005123:Eye / Q000187:drug effects; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D008875:Middle Aged; D011430:Propoxycaine / Q000494:pharmacology; D015203:Reproducibility of Results; D012677:Sensation / Q000187:drug effects / Q000502:physiology*
D000779:Anesthetics, Local; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C005717:proxymetacaine; D011430:Propoxycaine