Factors associated with changes in horizontal deviation after inferior oblique weakening surgery.

BACKGROUND/AIMS: To identify the factors affecting postoperative horizontal deviation following isolated inferior oblique (IO) weakening surgery. METHODS: The medical records of patients who had undergone isolated IO weakening surgery between February 2010 and September 2021, with a minimum follow-up period of 6 months, were retrospectively reviewed. Patients were divided into two groups, eso-shift, and non-eso-shift, based on the change in horizontal deviation at postoperative 6 months. Eso-shift or exo-shift was defined as a change of 2Δ or more. RESULTS: A total of 77 patients were included. Among them, 49 patients (63.6%) showed changes in horizontal deviation: 37 (48.0%) eso-shift, 12 (15.6%) exo-shift. Twenty-eight patients (36.4%) showed no change in alignment. The eso-shift group showed the following characteristics compared to the non-eso-shift group: older age (P < 0.001), higher proportion of patients with preoperative exo-deviation (P < 0.001), and greater preoperative hypertropia in primary gaze (P < 0.001), down gaze (P = 0.031), ipsilateral gaze (P < 0.001), and ipsilateral head tilt (P = 0.002). Regarding the postoperative changes in horizontal deviation based on prior horizontal strabismus, patients with preoperative exo-deviation showed a statistically significant eso-shift. The patients with prior eso-deviation tended toward exo-shift, while those without prior horizontal deviation rarely changed. CONCLUSION: Changes in postoperative horizontal deviation are associated with preoperative horizontal and vertical deviation, which might result from changes in the rectus muscle due to oblique muscle dysfunction. Also, this study suggests that isolated IO weakening surgery could effectively correct small-angle horizontal deviation in patients with inferior oblique overaction (IOOA) and horizontal strabismus.

Comparison of intraocular lens power calculation formulas in patients with a history of acute primary angle-closure attack.

BACKGROUND: To compare the accuracy of nine intraocular lens (IOL) power calculation formulas, including three traditional formulas (SRK/T, Haigis, and Hoffer Q) and six new-generation formulas (Barrett Universal II [BUII], Hill-Radial Basis Function [RBF] 3.0, Kane, Emmetropia verifying optical [EVO], Ladas Super, and Pearl-DGS) in patients who underwent cataract surgery after acute primary angle closure (APAC). METHODS: In this retrospective cross-sectional study, 44 eyes of 44 patients (APAC) and 60 eyes of 60 patients (control) were included. We compared the mean absolute error, median absolute error (MedAE), and prediction error after surgery. Subgroup analyses were performed on whether axial length (AL) or preoperative laser peripheral iridotomy affected the postoperative refractive outcomes. RESULTS: In the APAC group, all formulas showed higher MedAE and more myopic shift than the control group (all P < 0.05). In APAC eyes with AL ≥ 22 mm, there were no differences in MedAEs according to the IOL formulas; however, in APAC eyes with AL < 22 mm, Haigis (0.49 D) showed lower MedAE than SRK/T (0.82 D) (P = 0.036) and Hill-RBF 3.0 (0.54 D) showed lower MedAE than SRK/T (0.82 D), Hoffer Q (0.75 D) or Kane (0.83 D) (P = 0.045, 0.036 and 0.027, respectively). Pearl-DGS (0.63 D) showed lower MedAE than Hoffer Q (0.75 D) and Kane (0.83 D) (P = 0.045 and 0.036, respectively). Haigis and Hill-RBF 3.0 showed the highest percentage (46.7%) of eyes with PE within ± 0.5 D in APAC eyes with AL < 22 mm. Iridectomized eyes did not show superior precision than the non-iridotomized eyes in the APAC group. CONCLUSIONS: Refractive errors in the APAC group were more myopic than those in the control group. Haigis and Hill-RBF 3.0 showed high precision in the eyes with AL < 22 mm in the APAC group.

Extraocular muscle enlargement of indeterminate cause in pediatric patients: case series and literature review.

PURPOSE: To specify the clinical characteristics of enlarged extraocular muscles of indeterminate cause in pediatric patients based on a case series and literature review. METHODS: The medical records of pediatric patients who presented between January 2019 and January 2022 with enlarged extraocular muscles, where the underlying cause could not be determined, were retrospectively reviewed. RESULTS: Four patients were included. The main reason for presentation was evaluation of abnormal head posture. Head tilt or turn with duction deficit was observed in all patients. The age of onset ranged from 6 months to 1 year. Two patients presented with esotropia and hypotropia; the other 2 patients, with large-angle esotropia. Orbital imaging was performed in all cases and revealed unilateral rectus muscle enlargement sparing the muscle tendon. All 4 patients were found to have an enlarged medial rectus muscle. In the 2 patients with hypotropia, the inferior rectus muscle was also involved. No underlying systemic or orbital disease was found. There were no changes in the orbit or extraocular muscles on follow-up imaging test. The intraoperative forced duction test revealed severe restriction in the direction of gaze opposite to the primary field of action of the enlarged muscles. CONCLUSIONS: Enlargement of extraocular muscles should be considered in the differential diagnosis when large-angle incomitant vertical or horizontal misalignment and abnormal head posture are observed in infancy.

Agreement between Scheimpflug Camera and the Swept-source Optical Coherence Tomography Measurements in Keratometry and Higher-order Aberrations.

PURPOSE: To evaluate the compatibility of corneal curvature and astigmatism, and higher-order aberrations (HOAs) measured by the Scheimpflug camera Pentacam HR and the swept-source optical coherence tomography ANTERION. METHODS: This prospective study included normal subjects with no ophthalmic history. Steep keratometry (K), flat K, astigmatism and its axis of the anterior and posterior surfaces, total corneal power, and HOAs using the two instruments were compared. To compare the mean values of the measurements, a paired t-test was used. Bland-Altman analysis was applied to assess the agreement between the two devices. RESULTS: Fifty-three eyes of 53 subjects were evaluated. There were statistically significant differences for steep K, astigmatism, and vector J0, J45 in the anterior surface and total corneal power between the two devices (p < 0.05). There were also significant differences in the most of the keratometric values of the posterior corneal surface (p < 0.05) except J0 (p = 0.410). Both devices showed strong positive correlations in steep K, flat K, astigmatism (r > 0.81, p < 0.001) with wide ranges of a 95% limit of agreement. Vectoral components were significantly correlated (r > 0.78, p < 0.001) with narrow 95% limit of agreement, except J45 of the posterior surface (r = 0.39, p = 0.004). In the corneal HOAs, there were statistically significant differences in the vertical coma, horizontal trefoil, spherical aberration, and root mean square of each fifth- and sixth-order Zernike coefficient (p = 0.043, p = 0.041, p < 0.001, p < 0.001, and p < 0.001, respectively). Other HOAs showed moderate to strong positive correlations (r > 0.37, p < 0.05). Most HOAs, except for the horizontal trefoil, showed clinically acceptable agreements. The total root mean square of HOAs was not significantly different between the two devices (p = 0.122). CONCLUSIONS: Most of the keratometric values cannot be used interchangeably. However, the vectoral component of astigmatism showed clinically good agreement. Several HOAs have statistically significant differences; however, almost all HOAs showed acceptable agreements, except for the horizontal trefoil.