To investigate whether compression of the lid margin increase microbial contamination risk of patients undergoing cataract surgery

Inclusion Criteria:

• (1) Age > 60 years; (2) clinical diagnosis of age related cataract, without previous recent ocular surgery; (3) undergoing phacoemulsification with implantation of intraocular lens ; (4) able to give informed consent.

Exclusion Criteria:

• (1) any inflammation of the eye or other parts of the body within the previous 3 months; (2) chronic use of any types ophthalmic medication; (3) contact lens wear; (4) ocular surgery within the past 3 months; (5) use of systemic antibiotics within 30 days; (6) use of eyedrops in either eye within 3 days of enrollment; (7) need for concurrent glaucoma, cornea or other surgery.