Loss of binocular vision (diplopia) and acute comitant esotropia following surgical patch removal after unilateral penetrating keratoplasty for keratoconus; management.

Purpose: To report a case of acute comitant esotropia after monocular penetrating keratoplasty (PKP).

Case report: We present a 17 year old male patient with bilateral keratoconus who underwent penetrating keratoplasty in his right eye. He experienced diplopia after removal of the patch from the operated eye due to a new comitant esotropia in his left (unoperated) eye. Diplopia was controlled using prism glasses and then botulinum toxin injections until a penetrating keratoplasty was performed in his left eye and binocular vision and fusion returned.

Conclusion: Acute comitant esotropia may occur after loss of binocular vision and fusion due to brief ocular patching in a vulnerable patient. Fusion can be preserved with non-surgical methods until it can be permanently restored.