Aim: Comparative immunohistochemical study of expression of α A Crystallin in non-cataract lenses and age-related cataract lenses in humans.

Methodology: This was an observational cross sectional study. There are two groups in this study. Group A comprised of 121 senile degenerative cataract lenses from diagnosed patients. Group B included of 10 non-cataract lenses from patients who underwent surgeries for enucleation due to trauma and retinoblastoma. Lenses were fixed in 10% Buffered Neutral Formalin and processed to make paraffin blocks. Immunohistochemistry (IHC) staining was performed on sections using primary antibody for α A crystallin. Data was analyzed through SPSS software version 24.

Results: Immunohistochemical staining of group A showed 80.2% Strong Positive expression while 19.8% showed Intermediate Positive expression of α A Crystallin. 100% Strong Positive expression of α A Crystallin was seen in group B. Comparison of expression of α A Crystallin in two groups showed significant decrease (p<0.001) in expression.

Conclusion: Decreased expression of α A Crystallin in IHC stained senile cataract lens indicates the role of structural alterations of lens fibers in pathogenesis of senile cataract. If mechanism involved in causing these alterations can be identified and targeted so that progression of senile cataract may be delayed.

Keywords: Immunohistochemistry, α A crystallin expression, senile cataract, Human eye Lens, Lens Fiber.