Sir,

We thank Bhambhwani et al1 for their remarks, which we shall address in turn. With regard to Bhambhwani et al’s comments on ‘Vertical rectus transposition in Duane’s syndrome: does co-contraction worsen?’ we reported in Table 1 (complications part) that no case had lid fissures narrowing.2 For all patients, standardized preoperative and postoperative photographs were taken in the following manner. Photographs were taken at a fixed distance, under identical lighting conditions, with the patient in a sitting position, and with the eyes in primary gaze. The patient’s head was placed firmly in the head rest of a slit lamp and the lateral canthal angles were aligned with the side marks. An 18-inch metal bar had been fixed to the head rest of the slit lamp, projecting forward. The camera was held directly beneath the metal bar, moving forward or backward to focus on the patient’s lid margins. The patient was asked to fixate on the camera while the uninvolved eye was occluded. Photographs were taken with a digital camera (Cybershot DSC-F828; Sony Electronics Inc, Tokyo, Japan) with a macrolens at a reproduction ratio of 1:4.

Digital image analysis was used to standardize each patient’s preoperative and postoperative photographs for accurate objective comparison. Preoperative and postoperative photographs at the final follow-up examination were analyzed for margin-to-reflex distance (MRD), in mm, and used to access eyelid position. Adobe Photoshop version 7.0.1 (Adobe Systems Inc, San Jose, CA, USA) was used to measure the distance (pixels) from the center of the pupil to the upper eyelid margin (MRD1) and lower eyelid margin (MRD2), and the corneal diameter. The MRD1 and MRD2 were then standardized to an average horizontal corneal diameter (calculated as 11.6 mm in women and 11.7 mm in men), as described previously.3, 4 There was no statistically significant difference between the preoperative and postoperative standardized MRD (MRD1+MRD2) (independent samples t-test) (P=0.652). After vertical rectus transposition surgery (standard or augmented), there was no worse retraction or up- or downshoots.

As suggested by some authors,5 the electromyography of all patients was assessed preoperatively for confirmation of absence of anomalous lateral rectus innervation. No patients had anomalous lateral rectus innervation.

Figure 2A shows preoperative and postoperative photographs of a case with left type 1 Duane syndrome. For this patient, the preoperative MRD was 9.0 mm and the postoperative MRD was 9.5 mm. We did not determine an increase in globe retraction on adduction for the left eye.

Some authors reported that vertical rectus transposition surgery in cases of Duane’s retraction syndrome may worsen globe retraction or up- or downshoots.6, 7 However, other studies have determined that globe retraction or up- or downshooting did not worsen.8, 9 We did not notice any worsening of retraction or shoots in our patients on follow-up.