Recent contributions addressing intraocular lens (IOL) power calculation in patients undergoing cataract extraction following corneal refractive surgery using excimer laser were reviewed. Changes in corneal radii and keratometer index, as well as inaccurate prediction of postoperative IOL position using different formulas, were identified as error sources that led to inaccurate IOL power calculation. The current focus seems to be directed toward approaches not requiring preoperative refractive surgery information, however, the optimal solution to this continuing clinical problem has yet to be determined. At present, it is most important to inform the patient preoperatively regarding greater risk of inaccurate IOL power calculation.
Our purpose was to evaluate the clinical usefulness of a new binocular function testing device with head-mounted displays (Dr. REX®, OLYMPUS). In the first experiment, we measured subjective angle of deviation using Dr. REX® and synoptophore (Clement Clarke, London) for comparison with objective angle of deviation as measured using alternative prism cover test (APCT). In the second experiment, we measured motor fusion amplitude using Dr. REX® and synoptophore. Subjective angle of deviation as measured using Dr. REX® and synoptophore showed significantly reduced exodeviation as compared with objective angle measurement using APCT (p<0.01). The correlation between Dr. REX® and synoptophore for motor fusion amplitude was significant (p<0.01). Although attention must be paid to the intended use of this new device, the results suggest that it is also useful in screening examination.
Color perception is known to differ among individuals. One visual mechanism that can mediate that difference is the density of the macular pigment, which lies in front of the fovea, where it can absorb part of the light entering the eye. In order to verify whether this is a reason for individual difference in color perception, it is essential to conduct psychophysical experiments on subjects whose macular pigment density is known. In this study, we measured the macular pigment density of 44 subjects via heterochromatic flicker photometry. The result was an average density of 0.389, with standard deviation of 0.129. This result will enable us to conduct visual experiments that clarify the spectral sensitivity of these subjects, and determine whether there is any relation between color vision and macular pigment density.