Dissociated vertical deviation

Dissociated Vertical Deviation

Dissociated Vertical Deviation (DVD) is an ocular condition characterized by a slow, upward drifting of one eye when the other eye is fixating. It is often associated with strabismus, particularly infantile esotropia.

Clinical Features

DVD is typically asymptomatic and is often discovered during routine eye examinations. The condition is characterized by the following features:

• Vertical Drift: One eye drifts upward while the other eye maintains fixation.
• Latent Nature: The deviation is often latent, becoming apparent when the patient is fatigued or when one eye is covered.
• Bilateral Occurrence: Although it can affect one eye more than the other, DVD is usually bilateral.
• Variable Magnitude: The degree of deviation can vary over time and with different levels of alertness or fatigue.

Pathophysiology

The exact cause of DVD is not well understood, but it is believed to involve a disruption in the normal binocular vision development. It is thought to be related to an imbalance in the neural control of eye movements, possibly involving the vestibular system.

Diagnosis

Diagnosis of DVD is primarily clinical, based on observation of the characteristic upward drift of the eye. The following tests and observations are commonly used:

• Cover Test: When one eye is covered, the uncovered eye may drift upward.
• Alternate Cover Test: Rapid alternation of the cover between the eyes can reveal the dissociated nature of the deviation.
• Observation: The deviation may be more pronounced when the patient is tired or under stress.

Management

Management of DVD is often conservative, as the condition is usually asymptomatic. However, in cases where the deviation is cosmetically concerning or affects vision, treatment options include:

• Prism Glasses: These can help to align the eyes and reduce the appearance of the deviation.
• Surgical Intervention: Surgery may be considered to correct significant deviations, often involving weakening of the superior rectus muscle.
• Observation: In many cases, regular monitoring is sufficient, especially if the deviation is mild and not affecting vision.

Prognosis

The prognosis for individuals with DVD is generally good, as the condition is often asymptomatic and does not typically lead to vision loss. However, in some cases, it may be associated with other forms of strabismus that require treatment.

Related Conditions

DVD is often associated with other ocular conditions, including:

• Infantile Esotropia: A form of strabismus where one or both eyes turn inward.
• Latent Nystagmus: An involuntary eye movement that occurs when one eye is covered.
• Amblyopia: Reduced vision in one eye due to abnormal visual development.