Effects Of Proparacaine Hydrochloride Eye Drops On Rabbit's Central Corneal Thickness And Corneal Epithelial Morphology

Objective:To study the effects of0.5%Proparacaine Hydrochloride (PH) eye drops onrabbit's central corneal thickness (CCT) and corneal epithelial morphology.Methods:Right eye was randomly chosen and marked in20New Zealand white rabbits,then we give them3%pentobarbital for general anesthesia. CCT was consecutivelymeasured by Pentacam scheimpflug device, NT-530P-type intraocularpressure&corneal thickness measurement compound device and US pachymetrydevice before application of0.5%PH. Then,CCT was measured consecutively at1min,3min,6min,9min,12min,15min,18min and21min using above three methodsafter instillation1drop of0.5%PH. Before application and after each time point ofinstillation1drop of0.5%PH, we use in vivo confocal microscopy to observe theepithelium of the rabbit cornea in order to discovering whether it has morphologicallychanges.Results:Before application of0.5%PH, The average measurements of CCT byPentacam, NT-530P and ultrasound were350.50±16.40μm352.95±17.39μm330.65±17.08μm respectively.1min after application of0.5%PH, CCT measured byPentacam, NT-530P is362.00±16.74μm and366.05±16.33μm respectively, differencewas statistically significant (P＜0.05).3min after application, CCT is354.80±17.79μm and354.85±16.57μm respectively, there is not any significantdifference (P＞0.05). CCT in subsequent time periods showed no significant change(P＞0.05). However,there is no significant change in CCT measured by USpachymetry no matter you give1drop of0.5%PH or not(P＞0.05). There is mildchange of the superficial epithelium cells before and after instillation of PH byusing the IVCM, which presents transient characteristics of mild edema. Structure of other layers of the cornea does not show any significant change.Conclusions:Both Pentacam and NT-530P have good reproducibility and stability in assessingcorneal thickness. Measurement results of Pentacam and NT-530P can be affected by0.5%PH eye drops within1min, however, we can hardly see0.5%PH has effect onUltrasound pachymetry within1min. It's more reasonable to measure rabbit cornealthickness by Pentacam and NT-530P3minites after application of0.5%PH eye drops.0.5%PH eye drops can induce morphologically changes of the rabbit cornealsuperficial epithelial cell layer, which can recover within24hours.