Intraocular pressure changes at different gaze positions after superior rectus muscle-lateral rectus muscle loop myopexy in highly myopic strabismus.

PURPOSE: To evaluate changes in intraocular pressure (IOP) at different gaze positions before and after superior rectus muscle-lateral rectus muscle (SR-LR) loop myopexy in highly myopic strabismus (HMS). STUDY DESIGN: Nonrandomized clinical, prospective, interventional trial. METHODS: Fourteen patients with HMS (18 eyes) who underwent SR-LR loop myopexy were divided into 3 groups: < 100 prism diopters (PD) (mild esotropia [ET] group), > 100 PD (large ET group), and > 100 PD, and simultaneous recession of the medial rectus (MR) muscle was performed (large ET + MR group). Intraocular pressure was measured preoperatively and postoperatively at the primary, abduction, and adduction positions in each group. RESULTS: Intraocular pressure did not change after surgery in the mild ET group. Intraocular pressure significantly decreased in the abduction position (from 20.0 ± 2.1 to 16.0 ± 1.9 mmHg, P = 0.043) in the large ET group and in the abduction (from 22.2 ± 5.9 to 15.6 ± 4.3 mmHg, P = 0.048) and primary positions (from 15.8 ± 5.0 to 10.2 ± 2.8 mmHg, P = 0.043) in the large ET + MR group. The preoperative significant differences in IOP between the abduction and adduction positions in the large ET group (7.4 ± 3.4 mmHg) and the large ET + MR group (10.0 ± 5.5 mmHg) disappeared postoperatively (3.2 ± 2.8 mmHg and 3.6 ± 1.7 mmHg, respectively). The differences in IOP between abduction and adduction were similar in all the groups. CONCLUSION: SR-LR loop myopexy decreased IOP in patients with HMS in the abduction and primary positions.

Intraocular pressure at different gaze positions in patients with highly myopic strabismus.

PURPOSE: To evaluate intraocular pressure (IOP) at different gaze positions in patients with highly myopic strabismus (HMS). STUDY DESIGN: Nonrandomized, prospective, observational study. METHODS: This study included 18 eyes of 14 patients with HMS and 51 eyes of 51 age-matched controls without strabismus; these were further divided into two groups based on refractive errors: > -6.00 diopter (D) (n = 22 eyes) and ≤ -6.00 D (n = 29 eyes). IOP was measured in primary and side gazes and compared within and among groups. The relationships between IOPs and axial length, angle of globe dislocation measured on magnetic resonance imaging, strabismus angle, and degree of abduction deficit were studied. RESULTS: The HMS group showed higher IOP in abduction (19.3 ± 4.9 mmHg) than in the primary (12.5 ± 4.3 mmHg) and adducting positions (13.0 ± 3.3 mmHg), (p < 0.001). The IOP in the adducting position in the HMS group (13.0 ± 3.3 mmHg) was lower than in the control groups both with (17.6 ± 3.5 mmHg) and without (16.9 ± 4.1 mmHg) high myopia, ; (p < 0.001 and = 0.003). The difference in IOP between abduction and adduction was significantly larger in the HMS group (6.4 ± 4.6 mmHg) compared to others (p < 0.001) and positively correlated with the strabismus angle and the angle of globe dislocation and negatively with abduction deficit. CONCLUSION: The IOP of patients with HMS changes dramatically on side gazes, therefore, care should be taken while measuring IOP.

Exophthalmos associated with chronic progressive external ophthalmoplegia.

PURPOSE: Chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial disease characterized by slowly progressive ptosis and limitations in ocular motility. Although exophthalmos is not considered to be a common feature of CPEO, this study focused on the incidence of exophthalmos in patients with CPEO. STUDY DESIGN: Retrospective observational case series METHODS: We reviewed the clinical charts of patients who received a diagnosis of CPEO sometime during the period between January 2010 and December 2018. CPEO was diagnosed on the basis of detection of a deletion of mitochondrial DNA (mtDNA) from saliva, buccal mucosa, or extraocular muscle specimens obtained during strabismus surgery. Horizontal MRI/CT images or Hertel ophthalmometry was used in determining exophthalmos. RESULTS: Seven patients (4 males) were identified. The mean age at diagnosis was 32.6 years (range 13-53 years). mtDNA deletion mutations were detected in the buccal mucous membrane DNA in 5 patients and in the saliva and extraocular muscle DNA in 2 patients. MRI/CT was recorded in 6 patients, four of whom showed exophthalmos (cases 1-4), and case 5 was determined as exophthalmos on the basis of a Hertel ophthalmometer reading. Exophthalmos was bilateral in 4 of the patients (cases 1, 2, 4, and 5) and unilateral in 1 patient (case 3). Exophthalmos was the chief concern of 2 of the patients; however, it was not clinically significant in the other patients. CONCLUSIONS: Although exophthalmos may not be recognized by either the patient or the clinician, it may be one of the common features of CPEO. A large multiethnic study should be performed.

Medial Rectus Muscle Resection Versus Plication: A Comparison of Conjunctival-Scleral Thickness Measured by AS-OCT.

PURPOSE: To compare conjunctival-scleral thickness measured with anterior segment optical coherence tomography before and after medial rectus muscle resection and plication for exotropia. METHODS: In this prospective observational study, patients with exotropia aged 5 years and older who underwent medial rectus muscle resection or plication through limbal incision of the conjunctiva between April 2016 and June 2018 were enrolled. Conjunctivalscleral thickness was measured with anterior segment optical coherence tomography before and 3 and 6 months after surgery at 1.5 mm (limbus), 4 mm (insertion), and 5.5 mm (tendon) posterior to the scleral spur. One examiner made measurements twice blinded for the initial data. Conjunctival-scleral thickness was compared between groups using the Mann-Whitney U test. RESULTS: Twenty participants were divided into two groups: resection (n = 11) and plication (n = 9). The respective conjunctival-scleral thicknesses before and 3 and 6 months after surgery in the resection group were as follows: 0.76, 0.90, and 0.86 mm at the limbus; 0.86, 1.18, and 1.12 mm at the insertion; and 1.04, 1.41, and 1.33 mm at the tendon. Corresponding values in the plication group were as follows: 0.74, 0.87, and 0.81 mm at the limbus; 0.84, 1.16, and 1.08 mm at the insertion; and 1.00, 1.39, and 1.27 mm at the tendon. No between-group differences were observed at any location or time. CONCLUSIONS: No differences in conjunctival-scleral thickness were observed between the resection and plication groups before surgery or at 3 months and 6 months postoperatively. [J Pediatr Ophthalmol Strabismus. 2022;59(4):274-278.].

Effects of the Gaze Fixation Position on AS-OCT Measurements of the Limbus and Extraocular Muscle Insertion Site Distance.

PURPOSE: To investigate the effect of the gaze fixation position on measurement of the limbus and extraocular muscle (EOM) insertion site distance using anterior segment optical coherence tomography (AS-OCT). METHODS: Patients undergoing horizontal EOM surgeries were enrolled in this prospective experimental study. The distance between the angle recess and the muscle insertion site was measured using AS-OCT while patients fixed their gaze laterally or medially at inner or outer gaze fixation. The distance between the limbus and muscle insertion was intraoperatively measured using calipers. RESULTS: A total of 46 lateral rectus muscles and 36 medial rectus muscles of 44 patients were evaluated. Significant differences were observed between intra-operative measurements (6.3 ± 0.7 mm) and AS-OCT measurements (5.8 ± 0.7 mm) for the lateral rectus muscle at inner gaze fixation (P = .0017) and medial rectus muscle at outer gaze fixation (P = .0003); no difference was observed when the lateral rectus (6.4 ± 0.5 mm) and medial rectus (4.9 ± 0.6 mm) muscles were measured at outer and inner gaze fixation, respectively. Bland-Altman plots showed better consistency at outer gaze fixation than at inner gaze fixation for the lateral rectus muscle; the opposite was observed for the medial rectus muscle. More than 80% of the AS-OCT measurements were within 1 mm of the intraoperative measurements at outer gaze fixation for the lateral rectus muscle and inner gaze fixation for the medial rectus muscle. CONCLUSIONS: Gaze fixation at outer gaze fixation for the lateral rectus muscle and inner gaze fixation for the medial rectus muscle was an appropriate technique to assess limbus and EOM insertion using AS-OCT. [J Pediatr Ophthalmol Strabismus. 2021;58(1):28-33.].

Usefulness of handheld electroretinogram system for diagnosing blue-cone monochromatism in children.

PURPOSE: To report the diagnosis of three childhood patients with blue-cone monochromatism (BCM) using S-cone electroretinograms (ERG) recorded with RETeval® Complete. STUDY DESIGN: Prospective clinical study. METHODS: We examined three boys initially suspected of having rod monochromatism. S-cone ERG was performed with red background and blue flashed light stimulation using two different intensities: 0.25 cd × s/m2 and 1 cd × s/m2. RESULTS: Case 1 was a 12-year-old boy with a visual acuity of 0.1 OU. Case 2 was an 8-year-old boy with a visual acuity of 0.3 OD and 0.2 OS. Both cases showed a myopic fundus and nystagmus without any other ocular abnormalities. Case 3 was a 6-year-old boy with a visual acuity of 0.3 OD and 0.4 OS. He also showed myopic fundus changes, but nystagmus was not observed. Rod and maximal responses recorded with RETeval® were likely to be within normal range; however, cone responses were absent in all cases. S-cone ERGs showed positive responses at 40 ms with 0.25 cd × s/m2 intensity in Case 2, and at approximately 30-40 ms with 1.0 cd × s/m2 intensity in all three cases. These ERG findings led to a diagnosis of BCM. CONCLUSIONS: S-cone ERG of RETeval® was helpful in diagnosing with minimal invasion BCM in childhood patients.

Changes in conjunctival-scleral thickness after strabismus surgery measured with anterior segment optical coherence tomography.

PURPOSE: To evaluate changes in conjunctival-scleral thickness following strabismus surgery with anterior segment optical coherence tomography (AS-OCT). STUDY DESIGN: Prospective, observational, consecutive case series. METHODS: Distances between the conjunctival epithelium and inner scleral wall were measured with AS-OCT before and 3-5 months after strabismus surgery. The measurements were performed at 1.5 mm (limbus), 7.0 mm (insertion), and 8.0 mm (tendon) posterior to the scleral spur on the lateral rectus muscle (LR); and 1.5 mm (limbus), 4.0 mm (insertion), and 5.5 mm (tendon) posterior to the scleral spur on the medial rectus muscle (MR). Thirty-three extraocular muscles (20 LRs and 13 MRs) from 23 subjects were studied. RESULTS: Thicknesses were significantly less at the insertion (0.95-0.78 mm; p < 0.001) and tendon (0.99-0.78 mm; p < 0.001) after LR recession and at the tendon (1.21-0.92 mm; p = 0.02) after MR recession. Thicknesses were significantly greater at the insertion (0.82-1.07 mm; p = 0.01) and tendon (0.95-1.28 mm; p = 0.01) after MR resection or plication and at the limbus, insertion, and tendon (0.75-0.90 mm, 0.94-1.19 mm, 1.03-1.28 mm, respectively; all p = 0.04) after LR resection or plication. CONCLUSION: Conjunctival-scleral thicknesses showed various changes after recession and resection or plication. These findings may help detect previous surgical operations when conjunctival scarring and ciliary vessel changes are unclear.