Suppression of Binocular Vision

DEFINITION:

Suppression is a cortical phenomenon characterized by a decreased sensitivity to visual information from one eye under binocular conditions. The magnitude and depth of suppression is often variable and asymmetric, and is highly dependent upon the attributes of the target and environment, the patient’s attention, and associated visual conditions. Clinically significant suppression can be found to co-exist with non-strabismic and strabismic anomalies.

SIGNS AND SYMPTOMS:

The signs and symptoms associated with suppression may include, but are not limited to, the following:

1. eye turn/deviation (ICD: 9)
2. inaccurate/inconsistent depth judgment
3. incoordination/clumsiness (ICD:R27.8)
4. inaccurate eye-hand coordination
5. inconsistent work product
6. reduced efficiency and productivity
7. photophobia
8. abnormal postural adaptation/abnormal working distance (ICD: 3)
9. spatial disorientation
10. asthenopia
11. inconsistent visual attention/concentration or distractibility while performing visually demanding tasks

DIAGNOSTIC FACTORS:

Changes in the patient’s attention, binocular status, and stimulus conditions can alter the pattern of suppression. Suppression is characterized by one or more of the following diagnostic findings:

1. lack of awareness and utilization of visual information (partial or complete) from one eye when tested under binocular conditions
2. defective stereopsis (ICD: 32)
3. aberrant vergence and/or accommodative ranges
4. lack of diplopia and/or visual confusion in the presence of binocular misalignment (strabismus)
5. reduced monocular acuity under binocular conditions
6. range and depth of suppression area
7. latent target movement under vergence testing without report of diplopia

THERAPEUTIC MANAGEMENT CONSIDERATIONS:

The doctor of optometry determines appropriate diagnostic and therapeutic modalities, and frequency of evaluation and follow-up, based on the urgency and nature of the patient’s conditions and unique needs. Vision disorders that are not totally cured through vision therapy may still be ameliorated with significant improvement in visual function and quality of life. The management of the case and duration of treatment would be affected by:

1. the severity of symptoms and diagnostic factors, including onset and duration of the problem
2. the complications of associated visual conditions
3. implications of patient’s general health, cognitive development, physical development, and effects of medications taken
4. etiological factors
5. extent of visual demands placed upon the individual
6. patient compliance and involvement in the prescribed therapy regimen
7. type, scope, and results of prior interventions
8. occupational/avocational goals

PRESCRIBED TREATMENT REGIMEN:

The goal of the prescribed treatment regimen is to address the diagnostic factors and alleviate the presenting signs and symptoms associated with the diagnosed condition. Suppression is a visual deficit that is associated with other strabismic and non-strabismic anomalies. Successful and long- lasting treatment of suppression is dependent upon the effectiveness of the treatment of the associated visual conditions. In most patients that demonstrate suppression, the treatment requires optometric vision therapy as well as lenses and/or prisms. The optometric management of suppression incorporates the prescription of specific treatments in order to:

1. equalize performance of the two visual systems
2. increase awareness and utilization of visual information
3. establish accurate and stable motor alignment
4. establish stable sensory binocular fusion with stereopsis
5. increase visual stamina/integrate newly established skills with information processing

DURATION OF TREATMENT:

The following treatment ranges are provided as a guide. Treatment duration will depend upon the particular patient’s condition and associated circumstances. When duration of treatment beyond these ranges is required, documentation of the medical necessity for additional treatment services may be warranted for third-party claims processing and review purposes.

1. Suppression is not an independently treated condition. Its presence in conjunction with other conditions adds time to the overall treatment of those
2. The most common form of suppression found in a non-strabismic case can add up to 8 hours of office therapy. The most common forms of suppression in a strabismic case can add up to 20 hours of office
3. Suppression of binocular vision may require substantially more office therapy, if complicated by associated conditions such as cerebral vascular accident, head trauma, and/or other systemic conditions.

FOLLOW-UP CARE:

At the conclusion of the active treatment regimen, periodic follow-up evaluation is required. Should signs, symptoms, or other diagnostic factors recur, further therapy may be medically necessary.

Therapeutic lenses may be prescribed during or at the conclusion of active vision therapy to assist in the maintenance of long-term stability.