Severe complications of strabismus surgery.

PURPOSE: To determine the type, incidence, and clinical outcomes of severe complications from strabismus surgery in the United Kingdom. METHODS: Cases were identified prospectively through a national surveillance unit between September 1, 2008, and August 31, 2010. Questionnaire data were requested at the time of the complication recognition and at 6 months' follow-up. Outcome was graded I to V, with a poor or very poor outcome meaning either loss of corrected visual acuity or primary position double vision. RESULTS: A total of 60 completed reports of adverse events and complications were received during the study period. During the same time approximately 24,000 strabismus surgeries were performed in the United Kingdom, yielding an overall incidence of 1 in 400 operations (95% binomial confidence, 1 per 333-500 operations). The most common reported complication was perforation of the globe (19 [0.08%]), followed by a suspected slipped muscle (16 [0.067%]), severe infection (14 [0.06%]), scleritis (6 [0.02%]), and lost muscle (5 [0.02%]). Overall, complications were reported in adults and children in equal numbers; however, scleritis was significantly more common in adults. A poor or very poor clinical outcome was recorded as 1 operation per 2,400. CONCLUSIONS: This study provides an assessment of the overall risks associated with strabismus surgery in the United Kingdom. Complications with the potential for a poor outcome are relatively common, but the final clinical outcome is good in the majority of cases.

Bilateral changes in foveal structure in individuals with amblyopia.

PURPOSE: To examine foveal structure in amblyopia using spectral-domain optical coherence tomography (SD-OCT). DESIGN: Prospective, cross-sectional study. PARTICIPANTS AND CONTROLS: Two subject groups were recruited to the study: 85 amblyopes (34 adults, 51 children) and 110 visually normal controls (44 adults, 66 children). METHODS: A detailed eye examination, including an SD-OCT scan, was performed in all participants. A total of 390 eyes of 195 subjects were imaged using a 3-dimensional (3D) macula scan covering a nominal 6 × 6-mm area with a resolution of 256 × 256 (65,536 axial scans). Data from the B-scans bisecting the fovea both horizontally and vertically were fitted with a mathematical model of the fovea to determine a range of foveal parameters. MAIN OUTCOME MEASURES: Foveal thickness, foveal pit depth, and foveal pit slope. RESULTS: Bilateral differences between the eyes of amblyopes compared with visually normal controls were found. The difference between foveal structure in amblyopic participants relative to structure in subjects with normal vision persisted even when variables such as age, ethnicity, axial length, and sex were taken into account. Amblyopes showed increased foveal thickness (+8.31 µm; P = 0.006) and a reduction in pit depth in the horizontal meridian (-10.06 µm; P = 0.005) but not in the vertical meridian (P = 0.082) when compared with subjects with normal vision. Foveal pit slopes were found to be approximately 1 degree flatter in the nasal (P = 0.033) and temporal (P = 0.014) meridians in amblyopes, but differences between amblyopes and controls in the superior (P = 0.061) and inferior (P = 0.087) meridians did not reach statistical significance. No statistically significant interocular differences were found in the foveal structure between amblyopic and fellow eyes. CONCLUSIONS: Differences were found in the foveal structure in both eyes of amblyopes compared with subjects with normal vision. These differences consisted of increased foveal thickness, reduced pit depth when measured along the horizontal meridian, and flattening of the nasal and temporal sides of the foveal pit.

Nurse specialist treatment of eye emergencies: five year follow up study of quality and effectiveness.

The role of specialist nurses in triage, diagnosis and management of emergency eye conditions is well established, and encouraging reports of the safety and effectiveness of such services have been published. Specialist nurses in an emergency eye clinic in the UK seeing >7000 patients per year had been found at initial evaluation to treat 22% of the 1976 patients seen over a three month period without referring on to an ophthalmologist. A repeat of this evaluation five years later found this proportion had dropped to 17% (chi(2) = 16.7, p<0.01). In addition, the initial evaluation had found no incident of any patient having been treated and discharged by the specialist nurses returning to the department due to incorrect diagnosis or mismanagement. By contrast, from the sample 5 years later, 3 patients were identified who returned to the department due to possible misdiagnosis or sub-optimal management. We suggest that provision must be made for continuing professional development of nurses in this type of extended role, and the commitment to ongoing education should be backed up by a system of monitoring and critical incident reporting to facilitate skill maintenance and the life long learning process for specialist nurses.

Myectomy versus anterior transposition for inferior oblique overaction.

BACKGROUND: Inferior oblique overaction can be either secondary (as a sequela of ipsilateral superior oblique palsy) or primary (commonly associated with horizontal strabismus). Superior oblique underaction often coexists with both primary and secondary inferior oblique overaction. This retrospective case series compares the efficacy of inferior oblique myectomy versus anterior transposition in improving inferior oblique overaction and superior oblique underaction in eyes with either primary or secondary inferior oblique overaction. METHODS: One hundred twenty eyes of 81 patients were included in this retrospective case series, of which 20 had anterior transposition of the inferior oblique and 100 eyes underwent myectomy. Inferior oblique myectomy was compared with inferior oblique anterior transposition in improving inferior oblique overaction and superior oblique underaction in each diagnostic subgroup. Postoperative outcome was qualitatively and quantitatively assessed. Fisher's exact test was used to compare the outcomes. The quantitative improvement of function in terms of inferior oblique overaction and superior oblique underaction was analyzed by regression analysis. RESULTS: When postoperative inferior oblique overaction was considered, there was no statistically significant difference between myectomy and anterior transposition in both primary and secondary inferior oblique overaction. Myectomy was superior to anterior transposition in improving superior oblique underaction in both primary inferior oblique overaction (OR = 0.14; 95% CI, 0.015-1.45; p = 0.056) and secondary inferior oblique overaction (OR = 0; 95% CI, 0-0.027; p < 0.001). The quantitative improvement of function showed a significant difference between procedures for superior oblique underaction (t-test; p = 0.005; 95% CI, 0.25-1.3) but not inferior oblique overaction (t-test; p = 0.8; 95% CI, -0.67-0.54). CONCLUSIONS: This study demonstrates both inferior oblique myectomy and inferior oblique anterior transposition to be effective in correcting primary and secondary inferior oblique overaction. Myectomy is more effective in improving superior oblique underaction associated with both primary and secondary inferior oblique overaction. On this basis, we feel that inferior oblique myectomy has some advantage over anterior transposition in treating combined inferior oblique overaction and superior oblique underaction and can be considered the procedure of choice.

Comparison of modified anchored "hang-back technique (HBT)" with conventional HBT in bimedial rectus recession.

PURPOSE: We conducted a retrospective study to establish whether bimedial rectus recession (BMR) using a modified "hang-back technique" (HBT) is comparable with conventional HBT. METHODS: Consecutive patients younger than the age of 16 underwent BMR during 1999 and 2000 with at least a 6-month postoperative follow-up period were included. In 1999, all patients had operations performed with conventional HBT, whereas those in 2000 were conducted with modified HBT. Angles of strabismus were measured preoperatively and at 2 weeks, 2 months, and 6 months postoperatively. RESULTS: Thirty-nine and 43 patients underwent BMR using conventional and modified HBT respectively. Preoperative angles for near and distance were 43.6 (PD) versus 43.5 PD and 36.4 PD versus 36.8 PD. At 6 months' postop, the mean angles for near and distance were 6.4 PD Eso (range, 35 PD Eso - 40 PD Exo) and 5.4 PD Eso (range, 35 PD Eso - 35 PD Exo) in the conventional group: 8.1 PD Eso (range, 35 PD Eso - 20 PD Exo) and 6.3 PD Eso (range, 35 PD Eso - 25 PD Exo) in the modified group. The overall success rate (alignment to within 10 PD of orthotropia for distance and near) was similar between the two groups (conventional HBT:69.2% vs. modified HBT: 67.4%, P = 0.352). However, modified HBT was found to be associated with significantly lower consecutive exotropia rate postoperatively at 6 months (4.7% vs. 20.5%, P = 0.031). CONCLUSION: BMR using modified HBT is as effective as conventional HBT but with a significantly lower consecutive exotropia rate.

Reading speed test for potential central vision measurement.

This study examines the validity and reliability of a reading speed test as a measure of potential central vision. Reading speed was calculated in words per minute (wpm) from the time taken to read 30 words of 1.20 logMAR size text. Scores were obtained from subjects with cataract (n = 48), macular disease(n = 35), peripheral vision loss(n = 14) and normal eyes (n = 10). Subjects with macular disease (27.0 +/- 13.2 wpm) read much slower than subjects with cataract (91.9 +/- 13.6 wpm). Little difference was found between subjects with cataract, peripheral vision loss (91.5 +/- 14.7 wpm)and normal eyes (103.8 +/- 15.5 wpm). Repeat testing gave values within +/- 16% of reading speed. These results suggest that a reading speed test using large text could be useful as a potential central vision test in cataract patients.