Effects of Extraocular Muscle Surgery on 15 Patients With Oculo-Cutaneous Albinism (OCA) and Infantile Nystagmus Syndrome (INS) RICHARD W. HERTLE, MD, WILLIAM ANNINGER, MD, DONGSHENG YANG, PHD, RAED SHATNAWI, MD, AND VANESSA M. HILL, BS ● PURPOSE: The purpose of this report is to characterize the clinical and electrophysiological effects of extraocular muscle surgery in 15 patients with oculo-cutaneous albinism (OCA) and infantile nystagmus syndrome (INS). Our hypothesis is that surgery on the extraocular muscles of patients with OCA and INS changes their nystagmus and their visual function. ● DESIGN: Interventional, prospective, cohort, noncom- parative case series. ● METHODS: All 15 patients had surgery on all four virgin horizontal recti; three for strabismus alone, three for nystagmus alone, five for an eccentric gaze null zone alone, and four for an eccentric gaze null zone plus strabismus. All patients have been followed for at least six months. All 15 patients had the subjective outcome measure of pre- and postoperative binocular best optically corrected acuity (BBOCA). Objective outcome measures included anomalous head posture (AHP) in nine pa- tients, eye movement recording measures of expanded nystagmus acuity function (NAFX) in 10 patients, null zone position (NUZP) and null zone width (NUZW) in 10 patients, and foveation time (FOV) in nine patients. ● RESULTS: The results are summarized as follows; BBOCA increased 0.1 LogMar or greater in 14 of 15 patients. In those operated on for an AHP with or without associated strabismus the AHP improved signif- icantly (P < .01 for all). The NAFX, NUZP, NUZW, and FOV measured from eye movement recordings showed persistent, significant increases in all patients (P < .01 for all). ● CONCLUSIONS: This report adds to the evidence that surgery on the extraocular muscles in patients with INS has independent neurologic and visual results. (Am J Ophthalmol 2004;138:978 –987. © 2004 by Elsevier Inc. All rights reserved.) A LBINISM IS NOT A SINGLE ENTITY BUT REPRESENTS a heterogeneous group of inherited disorders of pigmentation. Despite a wide variety of manifesta- tions, all forms of albinism are characterized by varying degrees of several ocular features, including: nystagmus, photophobia, reduced visual acuity, and a lack of stereop- sis. 1–3 Involuntary ocular oscillations that begin in infancy and are associated with OCA have been classified in many ways, resulting in some confusion and disagreement among clinicians, physiologists, psychologists, and bioengi- neers. 1,4,5 The recently sponsored National Eye Institute Workshop on Classification of Eye Movement Abnormal- ities and Strabismus (CEMAS) has attempted to resolve some of these issues. 5 The CEMAS working group publi- cation outlining a definition of INS is used in this study. Nystagmus in infancy may also be attributable to structural disease of the brainstem and cerebellum, much the same as nystagmus in adulthood. 4 –7,8 Other clinical characteristics with variable association include: increased intensity with fixation, decreased intensity with sleep; variable intensity in different positions of gaze (null positions); changing direction in different positions of gaze (neutral positions); decreased intensity with convergence (damping); anoma- lous head posturing; strabismus; and the increased inci- dence of significant refractive errors. Infantile nystagmus syndrome is the predominant type of nystagmus associated with albinism. 1,9 Patients with INS and OCA usually have significantly diminished visual acuity, regardless of whether they have associated visual sensory defects. The visual acuity may be inversely related to the intensity of the nystagmus in Accepted for publication July 13, 2004. From the Department of Ophthalmology, Children’s Hospital of Pittsburgh, the Pittsburgh Eye and Ear Institute, Pittsburgh, Pennsylvania (R.W.H., D.Y.); the Department of Ophthalmology, Ohio State Univer- sity, Columbus, Ohio (W.A.); and Department of Ophthalmology, Columbus Children’s Hospital, Columbus, Ohio (R.S., V.M.H.). Inquiries to Richard W. Hertle, MD, Department of Ophthalmology, Pittsburgh Children’s Hospital, 3705 Fifth Ave, Pittsburgh, PA 15213; e-mail: Richard.hertle@chp.edu © 2004 BY ELSEVIER INC.ALL RIGHTS RESERVED. 978 0002-9394/04/$30.00 doi:10.1016/j.ajo.2004.07.029