Patients will be categorized into three Groups, according to DED severity. Group I comprises of subjects without DED, Group II of patients are evaluated as non-severe DED, and Group III consists of patients suffering from severe DED.~The day before cataract surgery will be performed patient examination, during standard cataract preoperative evaluation. Briefly, symptom-based assessment will be delivered by scoring the Ocular Surface Disease Index (OSDI) questionnaire, and evaluation of ocular surface damage will be performed by corneal fluorescein staining using the Oxford scale.~Before surgery, patients will be assigned to receive one drop of commercially available topical ofloxacin solution 0.3% at monodoses without preservatives (Oxatrex, Zwitter Pharmaceuticals, Greece) four times at fifteen minutes intervals starting 2 hours before surgery. The eye drops will be applied in the middle of the inferior lower fornix. Patients who miss any of the 4 doses will be excluded from the study. Aqueous humor will be collected after 1 hour of the last administration, intraoperatively, at the beginning of cataract surgery.~A paracentesis track will be made with a 15ᵒ superblade, a 30G cannula, connected to a tuberculin syringe, will be inserted into the A/C and approximately 50 μL of aqueous humor will be withdrawn. AqH samples will be collected in an Eppendorf tube. All samples will kept frozen at -20ᵒC.~Ofloxacin concentrations will be determined by HPLC-MS/MS.~DED severity, symptoms (Ocular Surface Disease Index) and signs (corneal staining using the Oxford score) will be correlated to ofloxacin's concentration in the AqH.
After topical installation of one drop of 0.3% commercially available ofloxacin (Oxatrex®) four times at intervals of 15min in catarract patients with Dry Eye Disease, aqueous humour samples will be collected intraoperatively, one hour after the last installation. Concentration of ofloxacin in aqueous humour will be measured by HPLC-MS/MS.