Mark S. Borchert

Nonorganic vision loss refers to claimed or measured impairment of visual acuity or field in the absence of demonstrable abnormality of visual pathway function. It may be due to malingering or to a psychogenic disturbance such as a conversion or somatization disorder.

URGENCY OF EVALUATION

Suspected nonorganic vision loss is not an urgent problem once the major signs of organic vision loss are ruled out.

DIAGNOSIS

DEMOGRAPHICS

Nonorganic vision loss can occur at nearly any age beyond 5 years. It usually occurs in older children and young adults.

SYMPTOMS

When taking a history or examining a patient with suspected nonorganic vision loss, the physician should not indicate his or her suspicions. This is important for two reasons. First, the suspicion as to the cause of the vision loss may be inaccurate, and exposing it may negatively impact the doctor patient relationship. Second, the reliability of several the tests for nonorganic vision loss depends on the suggestibility of the patient, which may be compromised by confrontation.

Visual Loss

Nonorganic vision loss may be unilateral or bilateral, severe or mild. When measuring acuity in these patients, always begin with the smallest line on the eye chart and then indicate surprise that the patient still cannot read the letters when they are “doubled” in size on the next largest line. The patient should be allowed several minutes to attempt to read each line. Check for consistency in the visual acuity using different optotypes and a near vision card. Always check for improvement in vision with a pinhole. In children, it can be suggested that the pinholes are “magic.”

Patient Behavior

Certain behaviors may raise suspicion for nonorganic vision loss. The patient may wear sunglasses despite claims of complete blindness. Unlike most blind persons, the patient may tend to look away from examiner. Another suspicious behavior is subnormal anxiety on the part of patient.

Past History

The examiner should try to elicit a history of recent psychological trauma. This could include death in the family, divorce, relocation, job change, school change, or harassment. History of recent physical trauma with litigious potential should also raise suspicion.

In children, nonorganic vision loss is often the result of a desire for glasses. The examiner should inquire if the patient’s friends wear glasses, and how long they’ve had them. He or she should inquire if the patient would like to wear glasses, if vision loss can be attributed to refractive error.

In children, a mild or transient vision problem may lead to parental anxiety and a visit to a physician. The child may then exaggerate the problem to demonstrate his or her veracity.

SIGNS

Red Flags

The following features should raise the question of alternate diagnoses:

Poorly reactive pupils or a relative afferent pupillary defect is an indication of retinal disease or optic neuropathy.

An abnormal or asymmetric red reflex when visualized through the ophthalmoscope can be a sign of anisometropia, corneal opacity, iritis, cataract, or vitreous hemorrhage.

Conjunctival redness or tenderness of the globe can indicate angle-closure glaucoma, infection, or uveitis.

Significant refractive error can be ruled out early in the evaluation without cycloplegia. This is achieved by performing retinoscopy or direct ophthalmoscopy on one eye while having the patient look in the distance with the other eye. The examiner should note if a significant corrective lens power needs to be dialed into the ophthalmoscope to visualize the optic fundus.

Abnormality of the optic fundus, for example, macular scar, subretinal hemorrhage, retinal detachment, or optic disc swelling

Strabismus of any type is often a sign of chronic vision loss. Esotropia (one eye turning in) or nystagmus suggests vision loss since early childhood.

ANCILLARY TESTS

SEVERE BILATERAL NONORGANIC VISUAL LOSS (20/400 OR WORSE)