How Does A Neurologist Assess Visual Field Loss? 

Medical conditions including glaucoma, stroke, traumatic injury, and other diseases or injuries affecting the eye or the regions of the brain that process vision, can damage the extent of a person’s visual field. These conditions are usually assessed, diagnosed, and treated by a neurologist or an ophthalmologist, depending on whether the deficit is in the eye or in the brain. 

What Kinds of Visual Field Deficits Are There?

There are four main types of visual field loss:

·         Altitudinal field defects - Loss of vision above or below the horizontal center of the visual field. These defects are usually caused by a deficit within the eye itself, rather than in the brain areas responsible for processing vision.

·         Bitemporal hemianopia - A loss of vision at both sides of the visual field.

·         Central scotoma - A loss of vision at the center of the visual field.

·         Homonymous hemianopia - Vision loss at one side in both eyes. This usually results from an injury to the optic chiasm, the point at which the optic nerves partially cross.

There are also other types and variants. For example, instead of a hemianopia, in which half of the visual field is affected, someone can have a quadrantanopsia, in which one quarter of the visual field is affected. A scotoma, which is a blank spot, can also take the form of a scintillating scotoma, a bright shimmering region. It depends on the cause and nature of the damage that caused the visual field deficit to occur. An expert neurologist is highly trained to identify and distinguish between the types and causes of visual field deficits. 

What Are Visual Field Tests? 

There are several types of tests that can be used to assess the nature of a visual field deficit.

·         A confrontation visual field exam is often given by a neurologist or ophthalmologist as a preliminary examination. The patient is asked to cover one eye and look at the examiner. The examiner then moves their hand, usually with a finger extended or while holding a pen, back and forth. The patient is asked to tell the examiner when the hand is or is not in their field of view.

·         In a Tangent Screen test, different sized white or colored pins are attached to a black wand and moved across a black background.

·         In a Goldmann Perimeter test, a hollow white spherical bowl is propped up to face the patient and is positioned at a fixed distance. Moving a light tests peripheral vision.

·         In Automated Perimetry, a patient presses a button to indicate when they see lights of incremental brightness.

These are some of the tests that can help a neurologist or ophthalmologist determine the nature and extent of visual field loss.        

Can Visual Field Loss Be Treated Or Cured? 

It is very rare for a person to recover completely from visual field loss; however, the power of neuroplasticity does allow some recovery to occur. There are several methods and processes by which someone can be treated for visual field loss.

·         Spontaneous recovery - Although spontaneous recovery is rare, it has been known to happen. It usually occurs within three months of the injury.

·         Interventional approaches - Sometimes training is used to help reduce visual field loss. Methods include:

o   Restorative training - There is ample evidence demonstration visual system neuroplasticity in animals, including humans. In Visual Restoration Therapy (VRT), visual stimuli are presented in the border region between the blind region and field of vision, often in one-hour daily sessions over a six-month period. This method may be more effective for patients with optic nerve damage than for those whose loss of visual field has its basis in the brain.

o   Optical aids - Aids, such as prism glasses, can help shift a patient’s visual field to reduce visual field loss.

o   Compensatory training - This is aimed at helping patients cope more effectively with their visual field loss, rather than remediating or reversing the loss. Patients are trained to make larger eye movements and other methods to aid in day-to-day functions, such as locating objects in the visual field.

There are various forms of visual field, depending on where the damage has occurred. Strokes, tumors, or trauma can damage brain areas associated with vision that result in a reduction of the visual field. If you live in the New York City area and would like more information on the forms of visual field loss, please contact us today! 

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