PurposeTo determine the effects of age and sex on the amplitude and latency scores obtained by the RAPDx® pupillometer, and to determine the standard values for detecting relative afferent pupillary defect (RAPD) in healthy subjects.MethodsThe study was conducted on 84 healthy subjects (52 males, 32 females), who had no ophthalmic diseases other than refractive errors with a mean age of 32 years. The amplitude and latency scores of the males were compared to that of females and also among the different age groups. The correlations between the amplitude and latency scores and age were determined. The standard values with the 90%, 95%, and 99% prediction intervals of the measured values were also calculated.ResultsThe differences in the amplitude and latency scores between the sexes were not significant. In addition, both scores were not significantly related with age. The mean amplitude score for all subjects with prediction intervals of 90%, 95%, and 99% was 0.02 (−0.26 to 0.30, −0.32 to 0.35, and −0.42 to 0.46, respectively); the latency score was −0.02 (−0.24 to 0.20, −0.28 to 0.25, and −0.37 to 0.33, respectively).ConclusionsRAPD is not present when the absolute values of the amplitude score and latency scores, measured by the RAPDx® pupillometer, are ≤ 0.2 log units. RAPD is present when either of the values are ≥ 0.5 log units.Translational RelevanceResults of this study can be used for detection of RAPD in the clinic and it will be the basic data of RAPDx® pupillometer for future research.

A new method is developed and validated for intraocular lens (IOL) power calculation based on paraxial ray tracing of the postoperative IOL positions, which are obtained with the use of anterior segment optical coherence tomography. Of the 474 eyes studied, 137 and 337 were grouped into training and validation sets, respectively. The positions of the implanted IOLs of the training datasets were characterized with multiple linear regression analyses one month after the operations. A new regression formula was developed to predict the postoperative anterior chamber depth with the use of the stepwise analysis results. In the validation dataset, postoperative refractive values were calculated according to the paraxial ray tracing of the cornea and lens based on the assumption of finite structural thicknesses with separate surface curvatures. the predicted refraction error was calculated as the difference of the expected postoperative refraction from the spherical-equivalent objective refraction values. The percentage error (within ±0.50 diopters) of the new formula was 84.3%. This was not significantly correlated to the axial length or keratometry. The developed formula yielded excellent postoperative refraction predictions and could be applicable to eyes with abnormal proportions, such as steep or flat corneal curvatures and short and long axial lengths.open Scientific RepoRtS | (2020) 10:6501 | https://doi.org/10.1038/s41598-020-63546-ywww.nature.com/scientificreports www.nature.com/scientificreports/ previously reported the relationship between the crystalline lens parameter and the IOL position 18 . Goto et al. 19 developed a formula to predict postoperative ACD, including the angle-to-angle (ATA) depth obtained by presented a method to accurately estimate and quantify the entire shape of the crystalline lens from OCT data, and reported that the preoperative anterior segment parameters were exceptionally valuable for estimating the IOL position. Yoo et al. 17 reported improvements in refractive outcomes by the ray-tracing method using the equatorial plane position of the lens.Paraxial ray tracing repeats simple calculations without special software or complexity. The predictive accuracy of IOL power calculations with paraxial ray tracing including the IOL positions predicted by the AS-OCT has not been clarified.Correspondingly, the aims of the present study are a) the development of a new formula based on paraxial ray tracing for IOL power calculations that utilize the postoperative IOL positions obtained using AS-OCT, and b) the validation of the accuracy of the developed formula. Scientific RepoRtS |(2020) 10:6501 | https://doi.

Purpose. This study was performed to investigate the relationships among crystalline lens shape, actual intraocular lens (IOL) position, and crystalline lens thickness (LT), as measured by anterior segment optical coherence tomography (AS-OCT), and to determine anterior ocular segment parameters that predict postoperative IOL position. Methods. Seventy-nine eyes of 79 patients who underwent uneventful cataract surgery were enrolled. For crystalline lens preoperative anterior segment data, the LT, and anterior, equatorial, and posterior surface depths (ASD, ESD, and PSD, respectively) of crystalline lenses were quantitatively determined. For postoperative anterior segment data, the actual IOL position was quantified. Moreover, the following correlations were analyzed: LT with the ASD, ESD, PSD, and IOL position; IOL position with the ASD, ESD, and PSD; and refractive prediction error with the difference between the predicted postoperative anterior chamber depth (ACD) of the SRK/T formula and the IOL position, ASD, ESD, and PSD (each depth minus the predicted postoperative ACD of the SRK/T formula). Results. The LT was significantly correlated with the ASD (r = -0.65) and PSD (r = 0.41), whereas it was not correlated with the ESD or IOL position. The IOL position was significantly correlated with the ASD (r = 0.67), ESD (r = 0.72), and PSD (r = 0.74). The refractive prediction error was significantly correlated with the difference between the predicted postoperative ACD of the SRK/T formula and the IOL position (r = 0.65), ASD (r = 0.46), ESD (r = 0.54), and PSD (r = 0.58). Conclusions. The ESD and PSD obtained using AS-OCT were highly correlated with the IOL position and significantly correlated with the refractive prediction error. These findings suggest that the ESD and PSD may enhance the accuracy of actual IOL position prediction.