Search

Blue light, with wavelengths shorter than 440-450 nm, is the most energetic radiation of the visible spectrum for the human eye, and its possible multiple effects on the human nervous and other systems have become a line of research by many investigators. The use of mobile devices whose screens emit various amounts of blue light is common nowadays. This study evaluated the efficiency of the blue light screen and control software technologies of eight different mobile devices. Emitted screen spectra of the different mobile devices according to different conditions of blue light emission software control were obtained using a spectrograph, and the derived spectra were compared with the melatonin suppression action spectrum. The amount of blue light emission and predicted melatonin suppression varied according to the unique software control and screen technology of each device. AMOLED screen technology, compared with other screen technologies, achieved better control of blue light emission. The effect of blue light filters depends on the screen technology; however, the melatonin suppression index of mobile devices is not reduced sufficiently by the use of blue light-attenuating software.

Purpose To characterize the optical performance of two models of refractive bifocal intraocular lenses, with medium and high addition, using defocus curves. Methods 20 eyes from 20 subjects were included in this study. 10 eyes underwent caratact surgery with an implant of a medium addition refractive bifocal intraocular lens (IOL) (Lentis LS-313 MF20) and the other 10 eyes underwent cataract surgery with an implant of a high addition refractive bifocal IOL (Lentis LS-313 MF30). Six weeks after surgery, subjective refraction and defocus curve were made. Results Mean final residual refraction in spherical equivalent was +0.10 ± 0.07 D in the LS-313MF30 group and +0.12 ± 0.10 D in the LS-313MF20 group. Defocus curve showed a different optical performance in intermediate/near distance depending on the IOL model. The medium addition IOL provided good visual acuity (VA) at far and intermediate distance up to 50 cms, and the high addition IOL provided better VA in near distance up to 25 cms. Conclusions The high addition intraocular lens provides better visual acuity in the spatial range from infinity to the point close to 25 cm. The medium addition intraocular lens provides excellent visual acuity in far and intermediate vision. The defocus curve seems to be a valid and reproducible tool for evaluating the optical behavior of multifocal sector refractive lenses. Objetivo Caracterizar el comportamiento óptico de dos modelos de lentes intraoculares bifocales refractivas, con adición media y alta, utilizando curvas de desenfoque. Métodos Se incluyó en este estudio a 20 ojos de 20 sujetos: 10 ojos sometidos a cirugía de cataratas con implante de lentes intraoculares (LIO) bifocales refractivas con adición media (Lentis LS-313 MF20), y los 10 ojos restantes sometidos a cirugía de cataratas con implante de LIO bifocales refractivas de adición alta (Lentis LS-313 MF30). Transcurridas seis semanas de la cirugía, se realizó refracción subjetiva y curva de desenfoque. Resultados La refracción residual final media en el equivalente esférico fue de + 0,1 ± 0,07 D en el grupo LS-313MF30, y de + 0,12 ± 0,1 D en el grupo LS-313MF20. La curva de desenfoque mostró un comportamiento óptico diferente en la distancia intermedia/de cerca, dependiendo del modelo de LIO. La LIO de adición media aportó buena agudeza visual (AV) en la distancia de lejos e intermedia, de hasta 50 cm, y la LIO de adición alta aportó mejor AV en la distancia de cerca de hasta 25 cm. Conclusiones Las lentes intraoculares de adición alta aportan mejor agudeza visual en el rango espacial comprendido entre el infinito y el punto próximo a 25 centímetros. Las lentes intraoculares de adición media aportan una agudeza visual excelente en la visión de lejos e intermedia. La curva de desenfoque parece ser una herramienta válida y reproducible para evaluar el comportamiento óptico de las lentes refractivas multifocales. Sin financiación No data JCR 2020 0.844 SJR (2020) Q2, 4/10 Optometry No data IDR 2020 UEM

Purpose: To analyze the reliability of the refractive results prediction obtained in intraocular lens (IOL) calculation using bicylindric power calculation method, with the use of steep and flat keratometry readings compared with the classical mean keratometry calculation method. Methods: Fifty-seven eyes of 57 subjects who underwent cataract surgery were included in this prospective study. Optical biometry was performed with IOLMaster 700 and IOL power calculation was performed using both keratometry readings and the surgically induced astigmatism. Four weeks after surgery, subjective refraction was done. Finally, results obtained with both IOL calculation methods were compared. Results: Mean spherical equivalent using bicylindric IOL power calculation method was -0.082 ± 0.296D, and achieved mean spherical equivalent using classical IOL power method with Haigis formula was -0.088 ± 0.405D. Achieved mean spherical equivalent obtained in subjective refraction after surgery was -0.101 ± 0.265D. Linear correlation between bicylindric method spherical equivalent calculation and achieved spherical equivalent was statistically significant (r = 0.761, P < 0.001), also correlation between Haigis spherical equivalent calculation and achieved spherical equivalent was statistically significant (r = 0.339, P = 0.010). Emmetropia was achieved in 49 of 57 (85.86%) subjects and bicylindric method calculated that 49 of 57 (85.86%) of subjects would get emmetropia (P = 1.000). Classical IOL power calculation estimated that 38/57 subjects would get emmetropia (66.67%) (P = 0.026). Conclusion: The IOL power calculation including both keratometry readings and surgically induced astigmatism seems to be more accurate and provides more precision in refractive prediction than classical calculation method.

Purpose: To compare and analyze the interchangeability of three measuring systems, each based on a different technique, for central corneal thickness (CCT) analysis. Methods: CCT measurements were measured using optical coherence tomography (OCT), non-contact specular microscopy (NCSM), and ultrasonic pachymetry (USP) in 60 eyes of 60 healthy patients with a mean age of 66.5 ± 15.0 years and a mean spherical equivalent of 0.43 ± 1.14 D. Analysis of variations in measurement concordance and correlation among the three different methods were performed. Comparison of CCT measurements were done using Bland–Altman plots (with bias and 95% confidence intervals), intraclass correlation coefficient (ICC), and paired t-student analysis. Results: Mean CCT values were: 549.20 ± 26.91 μm for USP (range 503–618 μm), 514.20 ± 27.49 μm for NCSM (range 456–586 μm) and 542.80 ± 25.56 μm for OCT (range 486–605 μm). CCT values obtained with NCMS were significantly lower than those obtained with OCT and USP methods. NCMS CCT value was 36.08 ± 10.72 μm lower than USP value (p

Purpose: To compare and analyze the accuracy of the refractive outcomes obtained in intraocular lens power calculation using the classical calculation method with mean keratometry (K) and the calculation method with both K meridians presented in this article. Methods: A total of 62 eyes of 62 subjects who were undergoing cataract surgery were included in this study. Optical biometry was performed using mean K and Haigis formula for classical intraocular lens calculation methods to achieve intraocular lens power; 4 weeks after surgery, prior to medical discharge, subjective refraction was made. Alternatively, intraocular lens power was calculated with bicylindric method using both keratometry readings, obtaining spherocylindrical refractive expected outcomes. Finally, results obtained with intraocular lens calculation methods, bicylindric method, and Haigis formula were compared. Results: Spherical equivalent calculated by classical intraocular lens calculation methods using Haigis formula (H-SE) was −0.027 ± 0.115 D and using bicylindric method (B-SE) was −0.080 ± 0.222 D. Achieved spherical equivalent obtained 4 weeks after surgery (A-SE) was −0.144 ± 0.268 D. Difference between H-SE and A-SE was −0.117 D (p = 0.002). Difference between B-SE and A-SE was not significant (−0.054 D, p = 0.109). Analysis in refraction groups showed a positive correlation between A-SE confronted to B-SE and H-SE (r = 0.313; p = 0.013 and r = 0.562; p < 0.001, respectively). This indicated a reliability in ametropic group prediction of 0.767 in H-SE and 0.843 in B-SE. Conclusion: Intraocular lens calculation with bicylindric method could be more accurate and had more reliability than classical intraocular lens calculation method. Bicylindric method adds astigmatism control and provides a reliable expected spherocylindrical refraction.

Purpose: To evaluate surgically induced astigmatism as computed by means of either simulated keratometry (KSIM) or total corneal refractive power (TCRP) after temporal incisions. Methods: Prospective observational study including 36 right eyes undergoing cataract surgery. Astigmatism was measured preoperatively during the 3-month follow-up period using Pentacam. Surgically induced astigmatism was computed considering anterior corneal surface astigmatism at 3 mm with KSIM and considering both corneal surfaces with TCRP from 1 to 8 mm (TCRP3 for 3 mm). The eyes under study were divided into two balanced groups: LOW with KSIM astigmatism SIM astigmatism ≥0.90 D. Resulting surgically induced astigmatism values were compared across groups and measuring techniques by means of flattening, steepening, and torque analysis. Results: Mean surgically induced astigmatism was higher in the HIGH group (0.31 D @ 102°) than in the LOW group (0.04 D @ 16°). The temporal incision resulted in a steepening in the HIGH group of 0.15 D @ 90°, as estimated with KSIM, versus 0.28 D @ 90° with TCRP3, but no significant differences were found for the steepening in the LOW group or for the torque in either group. Differences between KSIM- and TCRP3-based surgically induced astigmatism values were negligible in LOW group. Conclusion: Surgically induced astigmatism was considerably higher in the high-astigmatism group and its value was underestimated with the KSIM approach. Eyes having low astigmatism should not be included for computing the surgically induced astigmatism because steepening would be underestimated.

To compare and evaluate the agreement between the measurements obtained with a swept-source optical coherence tomography (OCT)-based biometer, the IOLMaster® 700 (IOLM), and those obtained by an optical biometer based on optical low-coherence interferometry (OLCI), the Aladdin (ALD); To evaluate the ability to perform biometric measurements in those eyes with transparency alterations. Fifty-five eyes of 55 subjects were included in this study. Axial length (AL), corneal power (K, in diopters) and its astigmatism, anterior chamber depth (ACD), central corneal thickness (CCT), and lens thickness (LT) measures were obtained within both biometers, Zeiss IOLMaster 700 and Topcon Aladdin. Results were analyzed and compared using the Student’s paired samples t-test, Bland–Altman analysis and intraclass correlation coefficient (ICC). Mean age was 73.12 ± 2.63 (62–89 years). The IOLM mean AL, K, and LT values did not show a statistically significant difference from ALD values and showed excellent agreement and correlation (ICC = 1.000, 0.970, 0.952). IOLM measured a lower mean ACD (−0.036 mm) and higher CCT measurements (9.296 μm). Those results were statistically different (p