Nystagmus blockage syndrome (NBS) presents clinically with which characteristic combination?

• A Latent nystagmus, esotropia that disappears on covering one eye, face turn toward the deviating eye
• B Vertical nystagmus, alternating esotropia, and head nodding
• C Pendular nystagmus, exotropia, and no preferred head posture
• D Congenital nystagmus with null point, esotropia in primary position, reduced nystagmus on adduction ✓

Explanation

Nystagmus blockage syndrome occurs when a child adopts convergence (and associated adduction) to dampen their congenital nystagmus — nystagmus is reduced in adduction (near the null point). The child develops esotropia in primary position as a strategy to utilise adduction for nystagmus suppression. A face turn toward the fixing eye (not the deviating eye) may accompany this. Treatment is aimed at the underlying nystagmus rather than the strabismus alone.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.