Following standard cataract surgery, impairment of vision may result from post-operative cystoid macular oedema (CMO). The purpose of the research is to assess the efficacy of preventive topical nepafenac (0.1%) in preventing post-operative macular edema following phacoemulsified cataract surgery & in preserving transoperative mydriasis. This 2-year study where the patients reporting to the Department OPD of Ophthalmology, undergoing the phacoemulsification cataract surgery will be part of the research. The study include 38 patients (two groups) & the study type is prospective, randomized, single-masked comparative study. For topical mydriatic usage, each treatment group will receive two doses of tropicamide 0.8% & phenylephrine 5% every fifteen minutes. Moreover, the nepafenac group received 4 doses starting an hour before surgery at a rate of only one drop once every fifteen minutes. Following surgery, all patients had a 4-week tapering period after receiving topical corticosteroid-antibiotic therapy (prednisolone + moxifloxacin) once for one hour for 15 days. One drop of nepafenac will be administered three times a day to the participants in the group being studied (the nepafenac group) starting the day before surgery & continued for six weeks following. Postoperative evaluations will be performed on the first day & Weeks 2 & 6 after surgery for all patients. Significant findings in the effectiveness of prophylactic tropical nepafenac is expected in the maintenance of transoperative mydriasis & prevention of post operative macular edema in the cataract surgery.