eye disorders
Acute Vision Loss
Evaluation of Acute Vision Loss
 should describe loss of vision in terms of onset, duration, progression, and location (whether it is monocular or binocular and whether it involves the entire visual field or a specific part and which part). Important associated visual symptoms include Floaters , flashing lights, halos around lights, distorted color vision, and jagged or mosaic patterns (scintillating scotomata). The patient should be asked about eye pain and whether it is constant or occurs only with eye movement. should seek extraocular symptoms of possible causes, including jaw or tongue claudication, temporal headache, proximal muscle pain, and stiffness ( Giant Cell Arteritis ); and headaches (ocular migraine). should seek known risk factors for eye disorders (eg, contact lens use, severe myopia, recent eye surgery, injection, or injury), risk factors for vascular disease (eg, Diabetes Mellitus (DM) , Family history should note history of Migraine . Vital signs, including temperature, are measured. If the diagnosis of a transient ischemic attack or stroke (ie, central Central Retinal Artery Occlusion and Branch Retinal Artery Occlusion ) presenting as amaurosis fugax is under consideration, a complete neurologic examination is done. The temples are palpated for pulses, tenderness, or nodularity over the course of the temporal artery. However, most of the examination focuses on the eye. Evaluation of the Ophthalmologic Patient includes the following: Visual acuity is measured. Peripheral visual fields are assessed by confrontation. Central visual fields are assessed by Amsler grid. Direct and consensual pupillary light reflexes are examined using the swinging flashlight test. Ocular motility is assessed. Color vision is tested with color plates. The eyelids, sclera, and conjunctiva are examined using a slit lamp if possible. The cornea is examined withfluoresceinstaining. The anterior chamber is examined for cells and flare in patients who have eye pain or conjunctival injection. The lens is checked for cataracts using a direct ophthalmoscope, slit lamp, or both. Intraocular pressure is measured. Ophthalmoscopy is done, preferably after dilating the pupil with a drop of a sympathomimetic (eg, 2.5%phenylephrine), cycloplegic (eg, 1%cyclopentolateor 1%tropicamide), or both; dilation is nearly full after about 20 minutes. The entire fundus, including the retina, macula, fovea, vessels, and optic disk and its margins, is examined. If pupillary light responses are normal and functional loss of vision is suspected (rarely), optokinetic nystagmus is checked. If an optokinetic drum is unavailable, a mirror can be held near the patient’s eye and slowly moved. If the patient can see, the eyes usually track movement of the mirror (considered to be the presence of optokinetic nystagmus). Acute loss of vision is itself a red flag; most causes are serious. Diagnosis of acute vision loss can be begun systematically. Specific patterns of Types of Field Defects help suggest a cause. Other clinical findings also help suggest a Difficulty seeing the red reflex during ophthalmoscopy suggests opacification of transparent structures (eg, caused by Corneal Ulcer , vitreous hemorrhage, or severe Retinal abnormalities that are severe enough to cause acute loss of vision are detectable during ophthalmoscopy, particularly if the pupils are dilated. Retinal Detachment may appear as a pale billowing parachute; retinal vein occlusion may show marked retinal hemorrhages; and retinal artery occlusion may show pale retina with a cherry-red fovea. An afferent pupillary defect (absence of a direct pupillary light response but a normal consensual response) with an otherwise normal examination (except sometimes an abnormal optic disk) suggests an abnormality of the optic nerve or retina (ie, anterior to the optic chiasm). In addition, the following facts may help: Monocular symptoms suggest a lesion anterior to the optic chiasm. Bilateral, symmetric (homonymous) visual field defects suggest a lesion posterior to the chiasm. Constant eye pain suggests a corneal lesion (ulcer or abrasion), anterior chamber inflammation, or increased intraocular pressure, whereas eye pain with movement suggests optic neuritis. Temporal headaches suggest giant cell arteritis or migraine. Erythrocyte sedimentation rate (ESR), C-reactive protein, and platelet count are done for all patients with symptoms (eg, temporal headaches, jaw claudication, proximal myalgias, stiffness) or signs (eg, temporal artery tenderness or induration, pale retina, papilledema) suggesting optic nerve or retinal ischemia to exclude giant cell arteritis. Other testing is listed in the table. The following are of particular importance: Ultrasonography is done to view the retina if the retina is not clearly visible with pupillary dilation and indirect ophthalmoscopy done by an ophthalmologist. Gadolinium-enhanced MRI of the brain and orbits is done for patients who have eye pain with movement or afferent pupillary defect, particularly with optic nerve swelling on ophthalmoscopy, to diagnose Multiple Sclerosis (MS) . 