I thank Dr Tong for his interest in our article. Dr Tong is correct in stating that, while a patient with congenital strabismus is spinning to the right, the intensity of a right-beating latent nystagmus (induced by left eye occlusion) increases because visual and vestibular input summate to drive the slow-phase eye movements to the left, as depicted in Figure 2B of our article. Our statement that “latent nystagmus decreases with spinning toward the fixating eye and increases with spinning toward the occluded eye” was meant to convey the change in latent nystagmus after the spin is suddenly stopped, as depicted in Figure 2C. Upon cessation of a rightward spin (with the left eye still occluded), the rightward slow phase of the postrotational nystagmus neutralizes the leftward slow phase of the latent nystagmus, thereby extinguishing the latent nystagmus. I agree that this distinction was not evident in the figure legend and thank Dr Tong for his clarification.
Brodsky MC. The Spin Test in Latent Nystagmus—Reply. Arch Ophthalmol. 2005;123(2):285. doi:10.1001/archopht.123.2.285-b