Purpose: To evaluate the efficacy of the augmented Anderson procedure in idiopathic infantile nystagmus (IIN).
Methods: Twelve consecutive patients older than 5 years having IIN with eccentric null position and anomalous head position were enrolled in an institution-based study. Best-corrected visual acuity (uniocular and binocular and in both null position and primary position), slit-lamp examination, fundus examination, ocular motility examination, and stereopsis using TNO were recorded. In all cases the augmented Anderson procedure, that is, recession of the yoke muscles (9-mm medial rectus and 12-mm lateral rectus), was performed. Eye movements were recorded before and 3 months after surgery in the primary position, right gaze 15 and 30 degrees, and left gaze 15 and 30 degrees.
Results: All patients had improvement in their anomalous head posture after surgery (p = 0.0001). The nystagmus intensity in the primary position decreased from 22.0 +/- 15.9 degrees cycles/s preoperatively to 10.6 +/- 10.2 degrees cycles/s at 3 months postoperatively. The change was statistically significant (p = 0.006). After surgery, binocular visual acuity using the Early Treatment Diabetic Retinopathy Study chart improved in primary position (p = 0.007). No patient developed more than mild limitation of horizontal movements after surgery.
Conclusion: The augmented Anderson procedure is successful in correcting face turn in patients having IIN with eccentric null position, resulting in an increase in visual acuity and a decrease in nystagmus intensity in primary position. Further studies with a longer follow-up are required to assess the long-term efficacy of this procedure.