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A Review of Low Vision Rehabilitation

Mark E. Wilkinson, OD

Contents

Comprehensive Case History

This is the most important aspect of the examination. It includes the following components:

During history taking, it is important to determine what types of visual difficulties your patient is experiencing because of their vision loss. There are many difficulties above and beyond reading or driving that may need to be explored. This is why a comprehensive history is so important.

Patients should also be asked about the occurrence of Charles Bonnet Syndrome in which formed, non-psychotic hallucinations of people, animals, etc. are seen by about 10 to 20% of patients with vision loss. Management of this syndrome includes physician recognition, empathy, reassurance, and patient education, which form the cornerstone of treatment. For this reason, consider initiating a discussion on Charles Bonnet by saying the following: “I often find that patients with a loss of vision experience phantom visions — perhaps streaks, flashes, or even faces or scenery—that seem unusual or hard to understand. Have you noticed anything like that?”

It should also be noted that depression is common among the elderly in general and is even more common among those who have experienced a significant loss in vision. This depression can be severe enough so as to require medical intervention to reduce the probability of self-destructive acts.

Ocular history should include a classification of vision loss. (Source: E. E. Faye, MD) Knowing the cause of your patient’s vision loss is important because it will help direct your examination and assist in the selection of devices that will be demonstrated to the patient. This is because each eye disease has a predictable effect on function, and the type and severity of the disease influences the ultimate effectiveness of any intervention.

The causes of visual impairment can be defined by the location of the pathology affecting the visual system: ocular media, retina, and/or brain.

Vision loss can be classified as: overall blur with no field defect, central field defect, and peripheral field constriction. The causes and management strategies for each classification will be discussed separately.

Overall Blur with No Field Defect. This condition typically occurs when the refractive media (cornea, pupil, lens or vitreous) become cloudy. In many cases of cloudy media, the individual’s complaint often seems out of proportion to their measured distance visual acuity. This is usually due to a significant change in their contrast sensitivity.

There are a variety of medical conditions that can cause this type of vision loss.

They include:

When there is overall blur with no field loss, the patient will typically report these symptoms:

However, there will be little effect on the following:

Central Field Defect This condition can occur from a variety of medical conditions including:

Patients with central field defects will often report the following symptoms:

However, the following will not typically be affected:

Peripheral Field Constriction Medical conditions that can cause peripheral field loss include the following:

Patients with peripheral field constriction will often report the following:

This function will probably not be affected in peripheral field loss:

Health history should include a general health review and a discussion of all medications currently and recently taken by the patient. Information on hearing/other impairments/conditions, orthopedic limitations, and self-care needs (e.g., ileostomy, diabetes) should also be obtained.

Specific questions about any co-morbidities such as the following should be asked:

Determination of the Patient's Vision Enhancement Needs

An extensive discussion regarding enhancement needs should focus on what may be very different requirements for distance, intermediate, and near tasks. Mobility, occupational, recreational, and daily living concerns should be explored in depth.

 

 

 
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