The accuracy of anterior segment optical coherence tomography (AS-OCT) in localizing extraocular rectus muscles insertions (original) (raw)
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Clinical Ophthalmology
The insertion-limbus distances of the extraocular muscles are clinically relevant in the preoperative planning of strabismus surgeries, especially in reoperations when information regarding insertion sites is not accessible to the surgeon. In this systematic review, we assess the reliability of time-domain anterior segment optical coherence tomography (TD AS-OCT) in determining insertion-limbus distances preoperatively by investigating prior studies that compare preoperative TD AS-OCT measurements of the insertion-limbus distances to those of calipers, which are assumed to be the gold standard. Methods: Systematically reviewing EMBASE, PubMed, Google Scholar, Science Direct, and Web of Science, 2 members screened for studies that compared preoperative TD AS-OCT measurements to those of intraoperative calipers, the gold standard. To assess the risk of bias for individual studies, the reviewers utilized the ROBINS-I tool, a Cochrane's collaboration tool used to assess bias in studies that are not randomized. For the meta-analysis, parallel forms reliability was examined and estimated as the Pearson productmoment correlation between TD AS-OCT measurements and surgical caliper measurements. Results: Six out of the seven eligible studies provided measures of reliability that were >0.7. These six records were eligible for metaanalysis. There was no evidence of a difference between means of TD AS-OCT and caliper measurements (μ ASÀ oct = 6.81, 95% CI [6.41, 7.22]; μ calipers = 6.73, 95% CI [6.18, 7.29]; Δ = 0.08, 95% CI [−0.44, 0.61]). Reliability was estimated to be good (ρ xx = 0.91) though the lower limit was slightly below the recommended minimum acceptable level of 0.70 (95% CI [0.65, >0.99]). Conclusion: In the setting of primary surgeries, TD AS-OCT has an acceptable reliability. However, there is insufficient data to conclude whether TD AS-OCT has an acceptable reliability in the setting of reoperations.
Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus, 2017
To compare the accuracy of widefield ultrasound biomicroscopy (UBM) with mechanical intraoperative measurements of the distance between rectus muscle insertions and the corneal limbus in strabismus reoperations. Subjects with a history of horizontal rectus muscle surgery who required further surgery on horizontal rectus muscle(s) were recruited prospectively. All widefield UBM measurements were carried out under topical anesthesia using a 50 MHz linear probe without immersion cup and external caliper. The insertion angle distance was measured using the caliper tool of the UBM device; the actual muscle insertion distance from the limbus was considered to be the measured distance plus 1 mm. The distance from muscle insertion to the limbus was also measured intraoperatively. The results of UBM and surgical measurements were compared. A total of 28 subjects were recruited, and 53 horizontal muscles (30 medial rectus, and 23 lateral rectus muscles) were included. The longest distance of ...
Clinical Ophthalmology (Auckland, N.Z.), 2021
Background To characterize the diagnostic role of swept source anterior segment optical coherence tomography (SS-ASOCT) in strabismus re-operations with lost surgical details. Methods Patients presenting to our outpatient services for strabismus care from February 2020 to March 15th 2021 were systematically evaluated. Those willing to undergo re-operation were included in the study. A total of 30 patients were identified and out of this a total of 10 eyes of 10 patients with lost surgical details were finally included in the study. Demographic details, preoperative deviation, ocular findings, orthoptic measurements, detailed SS-ASOCT findings, intraoperative measurements, and post-operative outcomes were recorded. Results The mean age of 10 patients was 23.7±5.75 years. Seven were male and three were female. The mean pre-operative SS-ASOCT measured distance from angle to insertion was 8.90±1.85 mm and the mean intraoperative distance was 9.12±2.14 mm. A mean difference of 0.21±1.31 ...
Minimally invasive strabismus surgery for horizontal rectus muscle reoperations
British Journal of Ophthalmology, 2008
To study if minimally invasive strabismus surgery (MISS) is suitable for rectus muscle reoperations. Methods: The study presents a series of consecutive patients operated on by the same surgeon at Kantonsspital St Gallen, Switzerland with a novel MISS rectus muscle reoperation technique. Surgery is done by applying two small radial cuts along the muscle insertion. Through the tunnel obtained after muscle separation from surrounding tissue, a recession, advancement or plication is performed. Results: In 62 eyes of 51 patients (age 35.4 (SD 16.3) years) a total of 86 horizontal rectus muscles were reoperated. On the average, the patients had 2.1 strabismus surgeries previously. Preoperative logMAR visual acuity was 0.38 (0.82) compared with 0.37 (0.83) at 6 months (p.0.1). On the first postoperative day, in the primary gaze position conjunctival and lid swelling and redness was hardly visible in 11 eyes, discrete in 15 eyes, moderate in 11 eyes and severe in 15 eyes. One corneal dellen and one corneal erosion occurred, which both quickly resolved. The preoperative deviation at distance for esodeviations (n = 15) of 12.5 (8.5)u decreased to 2.6 (7.8)u at 6 months (p,0.001). For near, a decrease from 12.0 (10.1)u to 2.9 (1.6)u was observed (p,0.001). The preoperative deviation at distance for exodeviations (n = 35) of 216.4 (8.5)u decreased to 27.9 (6.5)u at 6 months (p,0.005). For near, a decrease from 216.5 (11.4)u to 22.9 (1.5)u was observed (p,0.005). Within the first 6 months, only one patient had a reoperation. At month 6, in four patients a reoperation was planned or suggested by us because of unsatisfactory alignment. No patient experienced persistent diplopia or necessitated a reoperation because of double vision. Stereovision improved at month 6 compared with preoperatively (p,0.01). Conclusions: The study demonstrates that a small-cut, minimal dissection technique allows to perform rectus muscle reoperations. The MISS technique seems to reduce conjunctival and lid swelling in the direct postoperative period.
Extraocular muscle insertion shift after disinsertion during strabismus surgery
Strabismus, 2020
Purpose: To quantify the amount of insertion shift after disinsertion of the rectus muscles and identify factors that may influence the shift. Methods: Patients who underwent rectus muscle surgery between November 2018 and April 2019 were included. During surgery, the limbal-insertion distance (LID) distance was measured in millimeters with calipers from the limbus to the center of the insertion at the anterior border of the rectus muscle prior to and after disinsertion. The primary outcome was the shift of the rectus muscle insertion after disinsertion. This was calculated by subtracting the LID after disinsertion from the LID before disinsertion. The secondary outcome was the identification of preoperative and intraoperative factors that influenced insertion shift. Randomization was performed to select one rectus muscle per patient. Patients with a history of prior scleral buckle procedure, glaucoma drainage device, orbital wall fracture and strabismus surgery in the same rectus muscle were excluded. Results: 110 patients were included. The median (Q 1 , Q 3) LID before disinsertion was shortest for the medial rectus muscle [5.0 (4.5, 6.0)], followed by lateral rectus muscle [6.0 (6.0, 7.0)] and inferior rectus muscle [6.0 (5.5, 7.0)]. The overall median (Q 1 , Q 3) insertion shift was 1.0 (0.8, 1.0) mm (p < .001), which did not significantly differ between each rectus muscle subgroup (p = .158). Factors that influenced the amount of shift were moderate to severe restriction on forced duction testing (FDT) (B = 0.320, SE = 0.105, p = .003) and longer LID before disinsertion (B = 0.172, SE = 0.036, p < .001). Conclusions: We found a significant anterior insertion shift after disinsertion of rectus muscles. Moderate to severe restriction on FDT and longer LID before disinsertion can result in larger insertion shifts.
Graefe's Archive for Clinical and Experimental Ophthalmology, 2014
Purpose To purpose if this study was to determine whether the horizontal rectus muscle tendons (HRMTs) can be observed using anterior segment optical coherence tomography (AS-OCT) and to determine the repeatability of its measurements. Also, this study aimed to observe and measure the different external ocular structures at the level of the horizontal rectus muscle (HRM) insertion. Methods This was a retrospective, observational, descriptive and comparative study. Images were obtained utilizing the RTVue 100 CAM system. Eyes were analyzed at the three and nine o'clock position. Scans were performed for three different locations: the limbus, the ciliary body and the equator. All scans were analyzed by two graders, separately and blinded. Measurements were performed for: HRMT length; HRM thickness; conjunctival epithelium thickness; conjunctiva and Tenon's capsule thickness; scleral thickness; and external ocular thickness. Results Results were obtained from twenty eyes of ten volunteers. The conjunctival epithelium thickness was 52.33 μm, the total conjunctiva/Tenon's capsule thickness was 313.54 μm, the medial rectus (MR) thickness was 136.63 μm and the lateral rectus (LR) thickness was 181.65 μm. The MR tendon length was 1,426.88 μm, the LR tendon length was 1,433.65 μm, the scleral thickness was 489.91 μm and the total external ocular structure thickness was 785.17 μm. Intra-observer reproducibility (intraclass correlation coefficient [ICC]) for tendon length was 0.993 for grader #1, 0.989 for grader #2; the muscle thickness ICC was 0.990 for grader #1 and 0.981 for grader #2. The interobserver reproducibility ICC for tendon length was 0.557; the ICC for muscle thickness was 0.834. Conclusions It is possible to visualize and measure HRMTs using AS-OCT. Measurements of the HRM, as well as the surrounding external ocular tissues, can be achieved.
Minimally invasive strabismus surgery (MISS) for rectus muscle transpositions
British Journal of Ophthalmology, 2009
Purpose To present a novel, minimally invasive strabismus surgery (MISS) technique for inferior obliquus recessions. Methods Graded MISS inferior obliquus recessions were performed in 20 eyes of 15 patients by applying two small conjunctival cuts, one at the insertion of inferior obliquus and another where the scleral anchoring of the muscle occurred. Results The amount of recession was 12.2±2.3 mm (range 6 to 14 mm). The vertical deviation, which was measured in 25°of adduction, decreased from preoperatively 12.8°± 5.6°to 2.7°±2.2°(p<0.0001) at 6 months. LogMAR visual acuity was preoperatively −0.10 ± 0.17 and at 6 months −0.14±0.22 (p>0.1). In one eye (2.5%) the two cuts had to be joined because of excessive bleeding. Binocular vision improved in eight patients, remained unchanged in six patients, and decreased from 30 to 60 arcsec in one patient (p > 0.1). Conjunctival and lid swelling were hardly visible on the first postoperative day in primary gaze position in 10/20 (50%) of eyes. Five of the eyes (25%) had mild and five (25%) moderate visibility of surgery. One patient out of 15 (7%) needed repeat surgery because of insufficient reduction of the sursoadduction within the first 6 months. The dose-effect relationship 6 months postoperatively for an accommoda-tive near target at 25°adduction was 0.83°±0.43°per mm of recession. Conclusions This study demonstrates that small-incision, minimal dissection inferior obliquus graded recessions are feasible and effective to improve ocular alignment in patients with strabismus sursoadductorius.