Retinitis pigmentosa is a genetically disease consisting of progressive retinal degeneration starting in the rods. Its prevalence is 1:4000 people and is the fourth most common blinding disease in Israel in 2004 [7% of all blindness]. The investigators treated a non-progressive form of the disease [Fundus Albipunctatus] by oral therapy of the food supplement made from alga Dunaliella Bardawil composed of approximately 50% 9-cis β-carotene. The alga Dunaliella Bardawil accumulates high concentration of β -carotene when grown under appropriate conditions. The β -carotene of the alga is composed of approximately 50% of all-trans - β carotene and 50% 9-cis β -carotene.

The 9-cis β -carotene has been shown to be a precursor of 9-cis retinoic acid both in-vitro in human intestinal mucosa and in-vivo in a ferret, perfused with 9-cis b-carotene. The night vision, as measured objectively by electroretinography (ERG) more than doubled in six patients tested following treatment. The visual field was also improved significantly. In a more recent study the investigators treated 29 retinitis pigmentosa patients with the 9-cis b Carotene algae Dunaliella Bardawil in a double masked placebo control cross over trial. Significant improvement in retinal function was recorded in 34% of the patients.

Inclusion Criteria:

• Written informed consent to participate in the study.
• Men or women aged 18 years or older.
• Electroretinogram (ERG) responses compatible with the diagnosis of Retinitis Pigmentosa

Exclusion Criteria:

• Current smokers.
• Current use of Vitamin A/ beta carotene supplements.
• Active arterial disease within 3 months of study entry such as unstable angina, myocardial infarction, transient ischemic attack (TIA), stroke, and coronary artery bypass graft (CABG) surgery.
• History of malignancy, except basal or squamous cell skin carcinoma.
• Pregnant women, women who are breast feeding, and women of childbearing potential who are not using chemical or mechanical contraception.
• Uncontrolled hypertension defined as either resting diastolic blood pressure of >95mmHg (taken from the mean of 3 readings) or resting systolic blood Pressure of > 180 mmHg.
• History of alcohol abuse or drug abuse, or both.
• Patient plans to engage in vigorous exercise or an aggressive diet regimen.
• Uncontrolled endocrine or metabolic disease.
• Participation in another investigational drug study within 4 weeks of entry into this study.
• Serious or unstable medical or psychological condition that, in the opinion of the investigator, would compromise the subject's safety or successful participation in the study.
• Subject whose hormone replacement therapy (HRT) or oral contraceptive therapy (OCT) was initiated within the 3 month prior to enrollment.