Clinical Findings of Constant Exotropia Developed from Intermittent Exotropia

PURPOSE: To investigate clinical characteristics of constant exotropia patients with a previous history of intermittent exotropia. METHODS: Constant exotropia patients (CXT) with a previous history of intermittency, and intermittent exotropia patients (X [T]) who had undergone surgery for exotropia were included in the present study. Patching therapy of the fixating eye was performed for all patients. Surgical results, the effect of patching, lateral incomitancy, and suppression were retrospectively reviewed and compared between the 2 groups. RESULTS: The number of CXT was 51 and X (T) was 84. The angles of deviation at the initial visit and at surgery were significantly larger in CXT. After 3 months of patching therapy, there was no difference between the 2 groups in the reduction of distant angle of deviation. However, the reduction of near angle of deviation was 0.29 +/- 5.44 in CXT and 4.42 +/- 6.26 Delta in X (T), which was significantly different (p = 0.04). Lateral incomitancy was observed in 7.8% of CXT and 34.5% of X (T) (p < 0.001). The angles of deviation at the final visit and surgical success rate were not different between the groups. Preoperative suppression at distant was found in 100% of CXT and 88.7% of X (T), and postoperative suppression was in 17.6% and 18.3%, respectively. CONCLUSIONS: The surgical success rate and postoperative suppression were not different between constant exotropia and intermittent exotropia. However, the frequency of lateral incomitancy and the response to the patching therapy was lower in constant exotropia.

Effects of Eye Registration on the Astigmatism Correction in the Surface Laser Ablation

PURPOSE: To compare the effect of astigmatism correction upon Mel 80 excimer laser surgery with or without an eye registration system. METHODS: This retrospective analysis investigates a group (eye registration group) of surface laser ablation surgeries for myopic astigmatism correction, with operation on 27 eyes from 15 patients with guidance of the eye registration system and 40 eyes from 29 patients without guidance from the eye registration system. The evaluation of astigmatism correction was performed by the Alpins method, measuring the amount and axis of astigmatism before and after the operations. RESULTS: The average of the correction index (the ratio of the surgically induced amount of astigmatism correction to the intended amount of astigmatism correction) for the eye registration group was calculated to be 0.94+/-0.30 and, for non-eye registration group, was 0.92+/-0.41, showing no statistical significant difference between the two groups (p=0.762). However, the comparison of the index of success (the ratio of the difference vector to the intended amount of astigmatism correction) favorably demonstrated the effectiveness of eye registration (0.23+/-0.34 for eye registration group, 0.47+/-0.54 for non-eye registration group, p=0.03). The absolute angle of error (AE), a measure of difference in angle between the ablated axis of astigmatism correction and the desired axis of astigmatism correction, was lower on average for the eye registration group than for the non-eye registration group (3.52+/-7.69 to 12.5+/-20.69 degrees, p=0.015). CONCLUSIONS: Eye registration-guided surface laser ablation is suggested to be beneficial for the reduction of errors in astigmatism correction.

A Case of Congenital Absence of the Superior Oblique Muscle Treated With Anterior and Nasal Transposition of the Inferior Oblique Muscle

PURPOSE: To report a patient with absence of the superior oblique (SO) muscle of the left eye, who showed improvement after anterior and nasal transposition of the inferior oblique muscle for left hyperdeviation and right head tilt. CASE SUMMARY: A two-year-old boy presented with hypertropia of the left eye and right head tilt. Alternate prism-cover test in the primary position demonstrated 18 prism diopters (PD) of left hypertropia, which increased to 35 PD in the left head tilt position. A version test demonstrated overaction of the left inferior oblique muscle and underaction of the left superior oblique muscle. As an orbit CT scan showed absence of the SO muscle, the patient was diagnosed with congenital absence of SO and left anterior and nasal transposition of the inferior oblique muscle was performed. Three weeks after surgery, the patient presented with orthotropia at distant and near. The version test revealed normal oblique muscles. There was no vertical deviation shown on the Bielschowsky head tilt test. The abnormal head posturing was no longer observed. CONCLUSIONS: The authorsreport a patient manifesting abnormal head posture and hypertropia, diagnosed with absence of SO muscle, which was successfully corrected using anterior and nasal transposition of the inferior oblique muscle.