Metabolomic Profile in Dry Eye Syndrome Patients.

The primary objective is to determine possible implications of deviant tear film quality for optimal refractive precision in patients scheduled for cataract surgery.

The study consist of three separate arms where cataract patients will be separated in to Dry Eye Disease (DED) positive and negative groups. The DED positive group will be further subdivided into two different treatment groups (with focus on prolonged use of lubricant and preservative free eye drops). Tear film samples will be taken before treatment, after treatment and after surgical treatment and compared.

The participants will be randomized to either standard pre- and postoperative treatment protocol - hereby called the standard protocol - or a pre- and postoperative protocol where intensive dry eye treatment is implemented - hereby called the intensive dry eye treatment protocol. The intensive dry eye treatment protocol differs from the standard protocol in the use of preservative free eye drops and the use of topical steroids prior to surgery.

The standard treatment protocol is:

Before surgery:

* Nevanac 3 mg /mL
* Spersadex 1mg/ml three days before surgery.

After surgery:

Nevanac 3 mg /mL five days after surgery. Spersadex 1 mg/ml 20 days after surgery

The intensive dry eye treatment protocol is:

Before surgery:

Lubricants (Thealoz Duo) for four weeks. Preservative free dexamethasone 0.1% (Monopex) drops for one week Preservative free Diklofenak 1mg/mL drops (Voltaren minims) four times a day from three days before surgery.

After surgery:

Lubricants (Thealoz Duo) for three weeks. Preservative free dexamethasone 0.1% (Monopex) drops for three weeks. Preservative free Diklofenak 1mg/mL drops (Voltaren minims) for five days after surgery.

Biometry will be performed prior to and after the preoperative treatment, 6 weeks after surgery.

The variability in biometry measurements will be assessed for the standard protocol group versus the intensive dry eye protocol group. In addition, the average difference in estimated refraction and the actual refractive outcome (deltaR) will be calculated for both groups.

Differences in tear film instability before and after preoperative treatment, 6 weeks after surgery will be investigated.

Other variables to be investigated:

Average corneal curvature (K) Anterior corneal curvature Corneal astigmatism Mean spherical equivalent Dioptric keratometric power (estimated Intraocular lens (IOL) power) Best corrected visual acuity Tearlab osmolarity Non-invasive break up time(NIBUT) Tear meniscus height Bulbar redness grade Tear film lipid layer thickness (Lipiview) Ocular scatter analysis (HD analyzer) Cochet-Bonnet esthesiometry Ocular surface staining(OSS) Schirmers I test (without anesthetics) Meibum expressibility Meibum quality Meibomian gland dropout (meibography) Lid margin irregularities (yes/no) Tarsal conjunctival follicles/papillae (yes/no) Ocular surface disease index(OSDI) Dry Eye Quality of life questionnaire-5 (DEQ-5) Standard Patient Evaluation of Eye Dryness II (SPEED II)

Eligibility Criteria:
Inclusion Criteria:

* Indication for cataract surgery
* Signed informed consent
* no rheumatological or other systemic disease that involve the corneal surface
* a good ocular health with no pathology that compromises visual acuity (except cataract).

Exclusion Criteria:

* Manifest corneal disease or scarring
* Lid deformities
* Corneal ectasia
* Rheumatoid diseases or other systemic diseases that involve the corneal surface,
* Recent ocular surgery
* Previous refractive procedures
* Diabetic retinopathy
* Subjects who have an acute or chronic disease or illness that would confound the results of this investigation (e.g., immunocompromised, connective tissue disease, clinically significant atopic disease, diabetes, and any other such disease or illness)
* Pregnancy.