In the medical field, DVD most commonly refers to Dissociated Vertical Deviation, an eye movement disorder.
Dissociated Vertical Deviation (DVD) Explained
Dissociated Vertical Deviation (DVD) is characterized by the slow, upward drifting of one eye when the other eye is fixating on a target. This drifting is often accompanied by outward rotation (extorsion) and, sometimes, inward rotation (intorsion) of the eye. It's important to note that the "dissociated" aspect means the movement isn't directly linked to the movement of the other eye or an attempt to maintain single binocular vision.
Key Features of DVD
- Upward Drift: The affected eye slowly drifts upwards.
- Unilateral or Bilateral: DVD can affect one eye (unilateral) or both eyes (bilateral).
- Manifest or Latent: It can be constantly present (manifest) or only apparent when the eye is covered (latent). The "cover-uncover test" is used to identify latent DVD.
- Extorsion/Intorsion: The drifting eye often rotates outwards (extorsion) or, less commonly, inwards (intorsion).
- Association with Strabismus: DVD is frequently observed in individuals with other forms of strabismus (eye misalignment), particularly infantile esotropia (crossed eyes).
Diagnosis and Treatment
Diagnosis involves a comprehensive eye exam by an ophthalmologist or optometrist. Treatment depends on the severity and impact of the DVD and may include:
- Observation: Mild cases may not require any treatment.
- Eyeglasses: Corrective lenses can sometimes help improve eye alignment.
- Prism Lenses: Prisms can be incorporated into eyeglasses to redirect light and reduce the amount of eye deviation needed for comfortable vision.
- Eye Muscle Surgery: In more severe cases, surgery on the eye muscles may be necessary to improve eye alignment and reduce the frequency or severity of the upward drift.
Summary
DVD, or Dissociated Vertical Deviation, is an eye movement disorder where one or both eyes drift upwards, often with rotation, when the other eye is fixating. It is usually associated with other eye conditions like strabismus and can be managed through observation, glasses, prisms, or surgery.
