The red eye is one of the most common cause encountered in ophthalmic practice but a red eye is not always related to eye diseases, instead, it may be a clinical sign of several systemic diseases which may the alarmin signal of sight-threatening or life-threatening condition. Frequently, GPs, pediatricians, immunologists, and rheumatologists are the first landing of patients with a "red eye." This paper is addressed to non-ophthalmic specialists who may be faced with patients having a red eye. Inspection of the external eye under standard office lighting or with a bright light can be easily and accurately made by a general practitioner. Three major caveats should alert the GPs to promptly refer the patient to the ophthalmologist: the presence of pain; the loss of the natural corneal transparency and specular reflex; and any patient-described reduction of visual acuity. In most cases, a red eye is due to occasional and mild ocular surface reaction as consequence of exposure of the external eye to irritants and naturally occurring environmental agents. In these cases washing the eye with a tear lubricant may help in relief of symptoms. If this treatment fails within a few days, a consultation with an ophthalmologist is suggested. The role of the general physician is crucial in the decision making to judge the severity of the ocular condition. Managing a red eye often requires the support of other specialists. Our goal is not only to preserve vision but to globally cure the patient health.
Keywords: Acanthamoeba keratitis; bacterial keratitis; cornea stem cell; diseases of the ocular surface; diseases of the ocular surface: exposure keratopathy; immune disease of conjunctiva; immune disease of the cornea; tear deficiency states; viral keratitis.