(Reuters) - Swiss drugmaker Novartis said on Friday its treatment for a leading cause of age-related blindness had met its primary goals in a study and could potentially pave the way for less frequent dosing compared to a drug already on the market.

Developed by Novartis's eyecare unit Alcon, the RTH258 drug is intended to treat wet age-related macular degeneration (AMD), which causes severe loss of vision in the over 50s and occurs when the center of the retina, or macula, deteriorates.

Novartis said RTH258 demonstrated promising improvements in vision in the Phase II study that were as good as the popular treatment Eylea, produced by drugmakers Regeneron in the United States and Bayer elsewhere.

Patients treated every three months with RTH258 experienced prolonged effects of the treatment, which could potentially reduce the treatment burden, Novartis said, adding Alcon had started a late-stage Phase III trial of the drug.

Novartis already sells an older drug for AMD called Lucentis.

(Reporting By Zurich Slot; editing by Susan Thomas)