The general purpose of the study is to evaluate the potential beneficial effects of PEA 600 mg supplementation on RGCs function in subjects with glaucoma by pattern electroretinogram after three months of therapy.

Secondary objectives are to assess effects on intraocular pressure (IOP) values, if any; to record visual acuity, visual field, central corneal thickness (CCT), and Optical coherence tomography (OCT) (ganglion cell complex - GCC) changes, if any and to follow quality of life (QL) perception (general vision -GV and general health - GH of national eye instutute visual functioning questionnaire 25 items - NEI VFQ25)

Monocentric, randomized, prospective, single blind, two treatment and two period crossover study.

The investigators have proposed a cross-over trial to avoid or to detect the bias due to intra-individual variability and because, from preliminary observation, it has been noted that the effects of PEA on pattern-electroretinogram (PERG) are completely reversible after withdrawal, within one month.

The investigators didn't considered a placebo treated group because the patient cannot interfere with the pattern-electroretinogram PERG measurement that is objective and totally patient-independent.

Study duration 12 months Enrolment period 6 months Minimum Follow-up 6 months Start: January, 2015; end January, 2016 Total sample size: 40 patients

Inclusion Criteria:

• -age 18 years or older
• diagnosis of primary open angle glaucoma (POAG)
• controlled IOP (<18 mmHg, morning value) with any topical lowering medication (beta-blockers, carbonic anhidrase inhibitors, alpha2agonists, prostaglandin analogues as monotherapy or as associative therapy; betablocker/carbonic anhydrase inhibitor, betablocker/alpha2agonist, prostaglandine/betablocker and alpha2agonist/carbonic anhidrase inhibitor fixed combinations as monotherapy or in association);
• stable IOP<18 mmHg in the last 2 years
• stable disease in the last 2 years (no more than -1 deciBell-dB/year at MD of visual field)
• at least two reliable visual fields per year in the last 2 years
• no filtering surgery or other ocular surgery in the preceding 6 months
• written consent to participate to study procedures and data utilization in an anonymous form

Exclusion Criteria:

• ocular hypertension with normal optic nerve and visual field
• contraindication to PEA
• glaucomatous scotomas within 10 degree from fixation
• any condition limiting the patient's ability to participate in the study;
• other causes of visual field changes, such as cataract, myopic chorioretinopathy, macular diseases, retinal vascular occlusion

data will be published on peer review journal

upon publication

actually not available

examiners were blinded to the assumption or not of PEA in addition to topical therapy