System for detecting the retinal ischemia of a patient and method of determining a signal indicative of whether the blood flow within the eye of a subject is impaired, the method comprising the steps of: providing a hand-held device having a light source, a light diffuse reflector and at least one electrode positioning the device such that the at least one electrode contacts the skin of the subject proximate the eye activating the light source to direct light towards the eye of a subject, wherein the light diffuse reflector redirects the light to provide a substantially even illumination to the retina of the eye establishing the intensity of the light source based upon the area of the pupil of the eye so that the light stimulus to the retina of the eye is constant determining the diameter or area of the pupil of the eye detecting an electrical signal by the at least one electrode responsive to the stimulation of the eye by the light and determining said signal indicative of whether the blood flow within the eye is impaired by using a signal indicative of activating the light source and the electrical signal detected by the at least one electrode.患者の眼における深刻な網膜虚血を判定する電池駆動式の携帯型装置を提供する。この装置は、患者の眼における血流の低下の結果を検出し、光を出射する光源と、光源から患者の眼に向けて光を向け直す拡散器又は拡散回転楕円鏡とを備える。一組の電極は、患者の眼の近傍の皮膚に接触し、光刺激に対する眼の電気的応答を表す電気信号を受信する。マイクロコントローラは、患者の網膜虚血の度合いを判定するためのアルゴリズムを用いて電極が感知した電気信号を解釈する。一実施の形態においては、瞳孔の面積を測定し、これに基づいて光刺激の強さを決定する制御を行う。
