Accuracy of Optical Coherence Tomography Measurements of Rectus Muscle Insertions in Adult Patients Undergoing Strabismus Surgery

PURPOSE: To assess the accuracy of anterior segment optical coherence tomography (AS-OCT) in measuring the distance of extraocular muscle (EOM) insertion to the limbus to improve preoperative assessment of adult patients undergoing strabismus surgery. DESIGN: Reliability analysis. METHODS: SETTING: An institutional practice. PATIENT POPULATION: Seventy-four adult patients scheduled for strabismus surgery on rectus muscles. OBSERVATION PROCEDURE: The distance between the EOM insertion and the limbus was measured preoperatively with AS-OCT. The value was compared with the intraoperative measurement obtained with calipers. Additional measurements included the limbus-anterior chamber angle distance with AS-OCT and the axial length with IOLMaster. MAIN OUTCOME MEASURE: Agreement between preoperative AS-OCT and intraoperative measurements. A difference of 51 mm was "clinically acceptable." RESULTS: A total of 144 muscles were analyzed. Thirty-one of 33 reoperated muscles were successfully imaged. AS-OCT measurements were within 1 mm of intraoperative measurements in 77% of all muscles. The accuracy was higher for muscles with no prior surgery (83%), as compared with reoperated muscles (58%). Although the accuracy decreased when comparing reoperations to primary surgeries for the medial (79% to 63%P = .0995% confidence interval [CI], -1.38 to 0.11) and the lateral rectus (81% to 49%P = .1195% CI, -2.06 to 0.22), the difference was not significant. No correlation between limbus-anterior chamber angle distance and axial length was established. CONCLUSIONS: AS-OCT is valuable in identifying EOM insertions in primary strabismus surgeries, but the accuracy decreases in reoperations. (C) 2017 Elsevier Inc. All rights reserved.CAPES FOUNDATION, MINISTRY OF EDUCATION OF BRAZIL, BRASILIA, BRAZILUniv Miami, Miller Sch Med, Bascom Palmer Eye Inst, Dept Ophthalmol, 900 NW 17th St, Miami, FL 33136 USAUniv Fed Sao Paulo, Dept Ophthalmol & Visual Sci, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Ophthalmol & Visual Sci, Sao Paulo, BrazilWeb of Scienc

Combination of anterior segment optical coherence tomography modalities to improve accuracy of rectus muscle insertion location

Anterior segment optical coherence tomography (AS-OCT) is useful for locating the extraocular muscle insertion prior to strabismus surgeryhowever, its accuracy decreases in reoperations. This masked retrospective study investigated whether a combination of AS-OCT modalities improves accuracy. The distance between the corneoscleral limbus and extraocular muscle insertion was measured with AS-OCT, first using the standard grayscale modality alone and then refined with the color modality. The AS-OCT measurement was considered accurate when within 1.00 mm of the intraoperative caliper measurement. A total of 139 AS-OCT images were analyzed from 74 patients (mean age, 52 years), including 60 medial rectus (19 reoperations), 61 lateral rectus (11 reoperations), 10 superior rectus, and 8 inferior rectus muscles. Compared to grayscale alone, the combination grayscale/color modalities improved AS-OCT accuracy from 77% to 87% (P = 0.03), reflecting an increase from 83% to 94% (P = 0.01) in primary surgeries and from 53% to 60% (P = 0.60) in reoperations.Univ Miami, Miller Sch Med, Bascom Palmer Eye Inst, Dept Ophthalmol, Miami, FL 33136 USAUniv Fed Sao Paulo, Dept Ophthalmol & Visual Sci, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Ophthalmol & Visual Sci, Sao Paulo, BrazilWeb of Scienc

Strabismus surgery outcomes in eyes with glaucoma drainage devices

PURPOSE To report strabismus surgery outcomes in eyes with prior implantation of glaucoma drainage devices (GDD). METHODS The medical records of patients who underwent strabismus surgery for ocular misalignment that developed after implantation of a GDD over a 13-year period at a single institution were examined retrospectively. Patient characteristics, deviation types, preoperative measurements, surgical procedures, and postoperative measurements were analyzed. RESULTS Of the 16 patients included, 14 had exotropia (34(Delta) +/- 16(Delta)) and 11 had vertical deviations (15(Delta) +/- 7(Delta)), of which 9 had concurrent exotropia and vertical deviations. Preoperatively, 9 patients had diplopia. The surgical approach was tailored to address the deviation most noticeable to the patient horizontal, vertical, or both if the vertical component could be addressed by horizontal muscle supra- or infraplacement. Three patients underwent simultaneous horizontal and vertical surgery. All patients underwent strabismus surgery on an eye with a GDD. Surgical motor success (defined as horizontal deviation = 50% in magnitude. Diplopia resolved in 50% of patients who presented with preoperative diplopia. One patient had intraoperative bleb perforation, but none had postoperative hypotony at any follow-up visit. Only 2 required a second strabismus surgery. CONCLUSIONS Strabismus surgery with preservation of the filtering bleb following implantation of a glaucoma drainage device is a low risk procedure that can improve ocular alignment and related symptoms, despite a low motor success rate by standard criteria.Univ Miami, Miller Sch Med, Bascom Palmer Eye Inst, Dept Ophthalmol, 900 NW 17th St, Miami, FL 33136 USAUniv Fed Sao Paulo, Dept Ophthalmol & Visual Sci, Sao Paulo, BrazilUniv N Carolina, Kittner Eye Ctr, Chapel Hill, NC USAUniv Fed Sao Paulo, Dept Ophthalmol & Visual Sci, Sao Paulo, BrazilWeb of Scienc