Which of the following stain is used for diagnosis of Granular dystrophy of cornea?
Colloidal iron
Congo red
PAS
Masson trichrome
Ans: D. Masson trichrome(Ref: Kanski 7/e p212-224; Parson :s 22/e p212-214, 21/e p207-209; Yanoff and Duker 4/e p261).Masson trichrome stain - Used for granular corneal dystrophy diagnosis.Granular dystrophy:AD inheritance with gene locus on 5q31Onset: First decade with recurrent erosionsSigns (in chronological order):Small, white, sharply demarcated deposits resembling crumbs or snowflakes in central anterior stroma.Increasing number of lesions with deeper & outward spread but not reaching limbus.Gradual confluence causing visual acuity impairment.Histology:Shows amorphous hyaline deposits staining bright red with Masson trichrome.