Abstract
Abstract: :
Purpose: Commercial Multipurpose Solution (MPS) are widely prescribed in current contact lens market for convenient usage. There is still concern of the possible toxicity for the different chemical factors in the solution. Previous in vi–vitro tests on animal or human donated cornea basis have found the cell morphological and physiological change. This study compared human cornea basal epithelial cell numbers in vivo using a ConfoScan 3 confocal microscope, after 1–day application of MPS–A(containing polydronium hydrochloride) and MPS–B(containing poloxamine) to the contralateral control eyes. Methods: Eight neophyte healthy subjects ( age 22.6±1.53 ) were randomly selected: half to receive MPS–A and half to receive MPS–B in their test eyes only. The contralateral eyes served as control by receiving non–preserved saline. Double mask was applied to both investigators and subjects. One drop of solution was applied to each eye three times a day separated by three hour interval. The before / after test – slit lamp examination and confocal images (step 5µm, mag 1000×, light intensity 196 ) were recorded for safety and cell analysis purpose in the early morning as baseline and two hours after the last drop. Basal epithelia cell numbers were counted three times for each eye before and after the test under ConfoScan3 in the fixed frame of 0.03mm2 and converted to density. Results: For increased accuracy, more than 130 cells were counted in all 96 images in the frame. The average basal epithelia cell density for MPS–A test eye before test is 4852±292 cells/mm2, after test is 4939±473. Contralateral eye before test is 4941±484,after test is 5241±658. The cell density difference between the change of the MPS–A test eye and the change of the control eye is not significant according to the highly paired 1 sample t test (t= 0.53 P=0.63). For MPS–B group, test eye before test is 5109±266, after test is 4913±170; control eye before test is 5136±448, after test is 5275±633. The cell density change difference is also not significant statistically (t=1.84, P=0.16). In comparing MPS–A and MPS–B both test eye group, according to the 2 sample t test, no obvious difference was found for the cell density change (t=1.40,P=0.22). Conclusions: In neophyte subjects, using a ConfoScan3 confocal microscope, neither the MPS–A nor B solution showed evidence of acute increase in cornea exfoliation or damage when compared to the saline control. The difference between these two widely prescribed solutions was not found in this short term application.
Keywords: contact lens • ocular irritancy/toxicity testing • cornea: epithelium