Antiphospholipid syndrome is characterised by increased hypercoagulability leading to various retinal complications mainly retinal arteritis, vein and artery occlusion, ischemic optic neuropathy, transient loss of vision called amaurosis fugax and even diplopia or double vision. The Primolut you are on also increases coagulation and may worsen the existing scenario. Since you are experiencing visual symptoms, this is a precursor to an impending arterial or venous occlusion. Consult your doctor and mention the visual complaints. Primolut may have to be stopped in such a situation to prevent any retinal vascular damage.