Hypertropia

Hypertropia is a condition of misalignment of the eyes (strabismus), whereby the visual axis of one eye is higher than the other aligned eye.

Hypertropia may be either congenital or acquired, and misalignment is due to imbalance in eye muscle function. The superior rectus, inferior rectus, superior oblique, and inferior oblique muscles affect the vertical movement of the eyes.

Congenital cases may have developed abnormally due to poor muscle structure, usually muscle atrophy/hypertrophy or rarely, absence of the muscle and incorrect placement.

Specific and common causes include:

• Superior Oblique Palsy (IV Nerve)
• Inferior Oblique over reaction
• Double elevator palsy
• Fibrosis of rectus muscle in Graves Disease (most commonly inferior rectus is involved)
• Surgical trauma to the vertical muscles (e.g. during scleral buckling surgery or cataract surgery causing iatrogenic trauma to the vertical muscles)
• Brown’s Syndrome
• Duane’s Syndrome

Sudden onset hypertropia in a middle aged or elderly adult may be due to compression of the trochlear nerve and mass effect from a tumor, requiring urgent brain imaging using MRI to localize any lesion. It could also be due to infarction of blood vessels supplying the nerve, due to diabetes and atherosclerosis.

Dissociated Vertical Deviation (DVD) is a special type of hypertropia leading to slow upward drift of one or rarely both eyes, usually when the patient is inattentive.