Cytotoxicity evaluation of soft contact lens care solutions on human conjunctival fibroblasts.
ABSTRACT To determine whether different contact lens care solutions for soft lenses cause damage to human conjunctival cells.
Primary cultured human conjunctival fibroblasts were incubated with various concentrations of four different commercially available soft contact lens care solutions (OptiFree, Renu, SoloCare, Titmus) at concentrations of 5, 10 and 50 microl/ml medium. Toxicity was examined by determination of (1) the cell viability and mitochondrial activity with the colorimetric MTT test, and (2) the number of living cells with a cell analysis system (CASY 1) as compared with untreated cells.
For all four soft contact lens care solutions at a concentration of 5 mul/ml medium, no significant decrease in mitochondrial activity of the human conjunctival fibroblasts was found by the MTT test. At 10 microl/ml, only OptiFree and Titmus reduced mitochondrial viability significantly. The greatest reduction in mitochondrial activity occurred with all of the four soft contact lens care solutions at a concentration of 50 microl/ml. No significant decrease in the number of living conjunctival fibroblasts was observed by CASY 1 even at higher concentrations of the four solutions investigated.
This in vitro study demonstrates that the examined soft contact lens care solutions induce changes in mitochondria of human conjunctival cells only at higher doses as observed by the MTT test. However, this damage to the mitochondria did not lead to cell death as shown by the cell analysis system.
- Klinische Monatsblatter Fur Augenheilkunde - KLIN MONATSBL AUGENHEILK. 01/1996; 208(03):181-187.
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ABSTRACT: Topical medication applied chronically for the treatment of glaucoma changes the cellular profile of the conjunctiva. We wanted to determine the role of preservatives, which are usually combined with the drugs, on this effect. We applied metipranolol 0.3% and pilocarpine 2% with and without benzalkonium chloride 0.01% and cetrimonium chloride 0.004%, respectively. Twenty-four rabbits, divided into four groups, were treated for 3 months. The complete globes and the adherent bulbar conjunctiva were examined histopathologically and immunohistochemically. With special stains for collagen, a slight increase of the thickness of subepithelial collagen of the conjunctiva was present in both groups treated with medication and preservative compared with eyes treated with medication alone. This effect was also true for special antibodies for collagen type IV and alpha-smooth muscle actin in the eyes treated with pilocarpine, but not in the eyes treated with metipranolol. The results suggest that preservatives may have an additional adverse effect on the conjunctiva in addition to the effects of the medications alone.Albrecht von Graæes Archiv für Ophthalmologie 10/1994; 232(9):561-5. · 1.93 Impact Factor
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ABSTRACT: The effect of artificial tear solutions on the corneal epithelial barrier was evaluated by measuring corneal uptake of 5, 6 carboxyfluorescein (CF) after exposure of rabbit corneas to various formulations in a conjunctival cup. Four tear solutions containing 0.01% benzalkonium chloride (BAC), a formulation containing 0.001% Polyquad, a contact lens re-wetting solution containing 0.004% thimerosal, and each of the above preservatives in balanced salt solution (BSS) were evaluated. Four non-preserved solutions were also tested. After treatment with the solutions corneas were exposed to the CF, removed from the eyes and dialyzed in balanced salt solution. The CF concentration in the dialysate was measured by fluorometry. Solutions containing 0.01% BAC caused a 9.24 to 99.28 fold increase in CF uptake as compared to control. Solutions preserved with Polyquad or thimerosal caused only a 0 to 4 fold increase in CF uptake while non-preserved solutions caused no change compared to control. Corneas prepared for transmission electron microscopy using fixative containing ruthenium red exhibited damage which correlated well with CF uptake; the ruthenium red penetrated the epithelium to the basal cell layer after corneal exposure to solutions containing BAC while only superficial cell layers were stained after exposure to the other test solutions. The method used in this study allows statistical comparison of artificial tear formulations. The data show that patients with severe dry-eye who use artificial tears frequently should avoid tear solutions containing BAC and that non-preserved solutions are preferable for treatment of these patients.Current Eye Research 08/1991; 10(7):645-56. · 1.71 Impact Factor