Salehlake1272

PURPOSE To examine the clinical association between thyroid gland dysfunction and keratoconus. METHODS This was a cross-sectional case-control study conducted between May 2018 and July 2019. After performing Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) examination, flat, steep, and maximum simulated keratometric readings were recorded for each patient. Serum concentrations of free triiodothyronine, free thyroxine, and thyroid-stimulating hormone were measured. Further examinations by an endocrinologist were indicated for patients with positive laboratory results to confirm thyroid gland dysfunction. RESULTS One hundred eighty-seven patients with bilateral keratoconus and 187 sex- and age-matched healthy controls without keratoconus were analyzed. Mean age was 26.4 ± 8.2 years for the patients with keratoconus and 27.1 ± 9.4 years for the control patients, with no significant difference. selleck products The results showed that thyroid gland dysfunction prevalence was 10 of 187 patients with keratoconus (5.3%) and 2 of 187 control patients (1.1%), and the difference was statistically significant (P = .036). For the patients with keratoconus and thyroid gland dysfunction, 8 were women and 2 were men. Additionally, 6 patients (2 men and 4 women) had hyperthyrosis and 4 women had hypothyrosis. For controls, the two patients had hypothyrosis. CONCLUSIONS This study showed that there is a possible association between keratoconus and thyroid gland dysfunction, but more studies are needed to build upon these results. [J Refract Surg. 2020;36(4)253-257.]. Copyright 2020, El-Massry, Doheim, Iqbal, et al.PURPOSE To study the repeatability of anterior surface and Bowman's layer curvature in normal and keratoconic eyes using optical coherence tomography (OCT). METHODS In this study, 96 normal and 96 keratoconic eyes underwent corneal imaging using Pentacam (Oculus Optikgeräte, Wetzlar, Germany) and OCT (Triton, Topcon Corporation, Tokyo, Japan). The elevation data from segmented air-epithelium (A-E) and epithelium-Bowman's layer (E-B) interfaces in OCT scans were used to quantify curvature and aberrations. The wavefront aberrations were evaluated with the ray tracing method and 6th order Zernike polynomials. The intraclass correlation coefficient (ICC), within-subject standard deviation (Sw), and coefficient of variation (CoV) were used to assess repeatability. RESULTS For curvatures, the Sw was less than 0.25 diopters (D) for the normal and keratoconic eyes. The Sw was highest for root mean square of lower order aberrations (0.14 µm) in keratoconic eyes. The CoV for curvatures was well below 0.5% for both groups. For some aberrations irrespective of groups, the CoV was greater because some individual aberrations (mean of three successive measurements) tended to be smaller in magnitude and even a small Sw resulted in a high CoV. For all variables, the ICC ranged between 0.80 and 0.99 for both the OCT and Pentacam measurements. Most variables were similar between the A-E and E-B interfaces (P > .05) for both groups. However, both differed significantly from all Pentacam variables (P less then .05) in normal and keratoconic eyes. CONCLUSIONS The repeatability of OCT curvatures and aberrations compared well with the Pentacam indices for normal and keratoconic eyes. [J Refract Surg. 2020;36(4)247-252.]. Copyright 2020, SLACK Incorporated.PURPOSE To investigate lenticule decentration following small incision lenticule extraction (SMILE) via the pupil center or tear film mark centration method and compare induction of corneal higher order aberrations (HOAs) between the two methods. METHODS This study analyzed decentration values obtained from tangential topography difference maps of 100 eyes (100 patients) undergoing SMILE with the pupil center (n = 50) or tear film mark (n = 50) centration method. Total HOAs and component aberrations were measured preoperatively and 6 months postoperatively. Relationships between the magnitudes of decentration and induced corneal HOAs were assessed. RESULTS Both vertical and total decentered displacement were significantly different (P less then .001) between the two centration groups. A significant relationship between the preoperative pupillary offset and decentration was noted in the pupil center group (P less then .001), but not in the tear film mark group (P = .530). Significantly greater induction of total HOAs, coma, and vertical coma (all P less then .001), as well as horizontal coma (P = .001) and spherical aberration (P = .023), were observed in the pupil center group. Association between the total decentered displacement and induced total HOAs (P less then .001), as well as all other significantly increased phenomena, was also significant in the pupil center group. Differences in decentered displacement and induced corneal HOAs were significant for preoperative pupillary offset (angle kappa) greater than 200 µm, but not for angle kappa less than 200 µm. CONCLUSIONS SMILE with tear film mark centration can yield improved treatment centration and less induction of total HOAs, coma, and spherical aberrations. [J Refract Surg. 2020;36(4)239-246.]. Copyright 2020, SLACK Incorporated.PURPOSE To measure monochromatic aberrations at various wavelengths in eyes implanted with the Clareon monofocal aspheric intraocular lens (IOL) (Alcon Laboratories, Inc., Fort Worth, TX). The authors estimated longitudinal chromatic aberration (LCA), modulation transfer functions (MTFs), and the impact of interactions between chromatic and monochromatic aberrations on retinal image quality. METHODS Ten patients (age 68.4 ± 3.21 years) were measured in two experiments (1) Hartmann-Shack wave aberrations at five visible wavelengths (480 to 700 nm) and (2) best subjective focus at each wavelength. Objective and psychophysical LCAs were obtained from the Zernike defocus and psychophysical best focus, respectively. MTFs were calculated for the closest wavelengths to the peak sensitivity of the three cone classes (S [480 nm], M [555 nm], and L [564 nm]) using the measured aberrations and chromatic difference of focus. The degradation produced by LCA was estimated as the visual Strehl ratio for green divided by the visual Strehl ratio for blue and red.