Only the Other specialist (Erkut Küçük), who was not responsible for patient evaluation, knew which patient received which treatment during study periods. All patients were instructed to keep the vials (containing either AS or PFAT) in a refrigerator at 4 °C. All patients were advised to change the vial every other day during the treatment period. TBUT and ST I were administered by the same ophthalmologist (Uğur Yılmaz).