Ex-vivo method to quantifiably evaluate the staining effectiveness of anterior lens capsule dyes

Abstract

Purpose: High frequency of cataracts and the requirements of new European Union regulations for medical devices require the availability of preclinical models to adequatelyevaluateanteriorlens capsuledyes beforetheir usein patients.Herein, we describeanexvivomethodtoquantifiablyevaluatethemacroscopicandmicroscopic stainingeffectivenessofanteriorlenscapsuledyesusingporcineeyes. Methods: Commercially available trypan blue–based products or physiological saline solution(negativecontrol)wasinjectedintoporcineeyes.Anteriorpoleandlens(after extraction) were macroscopically photographed, and the images were quantitatively analyzed. Lenses were histologically processed, and the staining intensity microscopi- callywassemiquantified. Results: Macroscopic evaluation of the anterior pole revealed bluish staining of the anteriorcapsule;however,thiscoloringcannotbemacroscopicallydiscernedafterlens extraction.Quantitativeimageanalysesshowedsignificant(P < 0.01)stainingofthelens capsule compared to the negative control, but not significant (P > 0.05) between the productstested.Quantitativeanalysisofdyingonlensimagescouldnotbeperformed. Microscopicsemiquantificationofthecapsulestainingintensityallowsustoappreciate differencesbetweenproducts. Conclusions: The described method is a quick and useful tool for macroscopic evalu- ation by surgeons to choose an anterior capsule staining for use during everyday surgeries, and a more specific microscopic evaluation also allows us to determine the effectivenessandusefulnessoftheseproducts. Translational Relevance: This method satisfies preclinical effectiveness evaluations requiredbyEuropeanUnionregulationsandcomplementsthesafetyandtoxicityevalu- ationsthatnewproductsmustguaranteebeforetheyenterthemarketandareusedin clinicalpractice.