The objective of this study is to investigate corneal confocal microscopic findings, ocular signs and symptoms in patients on treatment with the preserved prostaglandin analogue latanoprost 0.005% eye drops (Xalatan®) and after the switch to preservative-free prostaglandin analog tafluprost 0.0015% eye drops (Taflotan®). Patients who have been using latanoprost as their prior medication (at least 6 months) and who fulfil all the inclusion criteria including the specified ocular symptoms and signs, will switch from latanoprost 0.005% eye drops to the assigned preservative-free tafluprost 0.0015% eye drops for twelve (12) months.

Primary outcome measures:

1. Change from screening in corneal confocal microscopic findings at month 12

2. Change from screening in ocular symptoms upon non-instillation at month 12

3. Change from screening in ocular signs at month 12

   Safety and QoL variables:

4. Descriptive statistics, identification of change(s) from screening

Inclusion Criteria:

• Have provided a written informed consent
• Aged 18 years or more
• A diagnosis of ocular hypertension or open-angle glaucoma (either POAG or capsular glaucoma) in one or both eyes, for which the patient has been regularly using latanoprost 0.005% (Xalatan®) for at least six months before Screening (confirmed in anamnesis)
• In the Screening visit evaluation, the presence of:

At least two ocular symptoms considered for the two eyes together (irritation/burning/stinging, foreign body sensation, tearing, itching or dry eye sensation) of at least mild severity (grade ≥ 2) upon non-instillation OR One ocular symptom of at least mild severity (grade ≥ 2) upon non-instillation AND

At least one of the following ocular signs in either eye with prior treatment:

Fluorescein tear break-up time (fBUT): less than 10 seconds

Corneal and conjunctival fluorescein staining:

Corneal fluorescein staining score of at least grade I OR Combined nasal and temporal staining scores of at least grade II Blepharitis: of at least mild severity (grade ≥ 1) Conjunctival redness/hyperemia: of at least mild severity (grade 1) Tear production: 10 mm or less on Schirmer test

• A best corrected ETDRS visual acuity score of +0.6 logMAR or better in both eyes
• Negative pregnancy test result at the screening visit, or, consistently and correctly used reliable method of contraception during the study
• Are willing to follow instructions

Exclusion Criteria:

• Females who are pregnant, nursing or planning a pregnancy, or females of childbearing potential who are not using a reliable method of contraception
• Anterior chamber angle in either eye to be treated less than grade 2 according to Schaffer classification as measured by gonioscopy
• Any corneal abnormality or other condition preventing reliable applanation tonometry, including prior refractive eye surgery
• IOP greater than 22 mmHg at 15:00 IOP measurement in either eye at Screening/Baseline visit
• Use of preserved eye drops (other than latanoprost) including artificial tears at screening or within two weeks prior to screening visit
• Diagnosis of angle-closure glaucoma or secondary glaucoma other than capsular glaucoma in either eye
• Suspected contraindication to tafluprost therapy (hypersensitivity to tafluprost or any of the excipients)
• Glaucoma filtration surgery or any other ocular surgery (including ocular laser procedures) within 6 months prior to Screening in eye(s) to be treated with study medication
• Use of contact lenses at Screening or during the study
• Any ocular (e.g. aphakia, pseudophakia with torn posterior lens capsule2 or anterior chamber lenses,known risk factors for cystoid macular oedema or iritis/uveitis), systemic or psychiatric disease/condition (e.g.uncontrolled arterial hypertension, diabetes) that may put the patient at a significant risk or may confound the study results or may interfere significantly with the patient's participation in the study as judged by the investigator
• Current alcohol or drug abuse
• Current participation in another clinical trial involving an investigational drug/device, or participation in such a trial within the last 30 days