Search

Kayo Shinomiya,1 Takashi Fujikado,2 Akiko Kitora,1 Satoe Okamoto,1 Akiko Iwata,1 Yoko Ogushi,1 Yoshinori Mitamura1 1Department of Ophthalmology, Graduate School of Medicine, Tokushima University, Tokushima, Japan; 2Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, JapanCorrespondence: Kayo ShinomiyaDepartment of Ophthalmology, Graduate School of Medicine, Tokushima University, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, JapanTel +81 088-633-7163Fax +81 088-631-4848Email shinomi@tokushima-u.ac.jpPurpose: We aimed to compare the depth perception under a microscope between binocular and monocular conditions using a newly developed microscopic stereotest (M-stereotest) and examine the effect of anisometropia on depth perception under a microscope.Subjects and Methods: Thirty young and healthy subjects were examined. A manipulator attached with a stainless wire was placed under the objective lens of a stereomicroscope. The wire was moved up manually, and the subjects were instructed to stop the knob movement once the wire reached the same height as the fixed two wires. The deviation from the height of the fixed wires was measured under a best optically corrected binocular, a best optically corrected monocular, or an anisometropic binocular [± 3 diopters (D) in the dominant or nondominant eye] condition.Results: The deviation was significantly smaller in the binocular condition than in the monocular dominant eye condition (0.38 ± 0.26 mm vs 1.89 ± 1.15 mm, p < 0.001) and was also significantly smaller in the best optically corrected binocular than in the anisometropic binocular condition [1.07 ± 1.00 mm (− 3.0 D), p = 0.003; 0.85 ± 0.67 mm (+3.0 D), p < 0.001].Conclusion: Depth perception under the microscope is more accurate under the binocular than in the monocular condition, indicating the potential role of stereopsis. Anisometropia deteriorates depth perception, suggesting that refractive error should be corrected during microscopic work, such as during ophthalmic surgery.Keywords: anisometropia, dynamic stereopsis, stereopsis, three-rods test

Masakazu Hirota,1 Hiroyuki Kanda,1 Takao Endo,2 Takeshi Morimoto,1 Tomomitsu Miyoshi,3 Takashi Fujikado1 1Department of Applied Visual Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; 2Department of Ophthalmology, Osaka University Graduate School of Medicine, Izumi, Osaka, Japan; 3Department of Integrative Physiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan Purpose: This study aimed to evaluate binocular coordination using video-oculography during smartphone reading in patients with intermittent exotropia compared to individuals with normal vision. Patients and methods: Eleven youth and adult patients with intermittent exotropia (21.9±9.3 years) and 15 control subjects (26.6±4.3 years) were examined. Eye movements were recorded during smartphone reading at 50, 30, and 20 cm using video-oculography. The loss of binocular coordination was tentatively defined as a horizontal disparity greater than 2°. The proportion of monocular viewing was the percentage of time for which binocularity was lost during smartphone reading. The proportion of monocular viewing, the reading speed, and the correlation between proportion of monocular viewing and reading speed were analyzed. Results: The proportion of monocular viewing during smartphone reading was significantly higher in the intermittent exotropia group than in the control group (P

Suguru Miyagawa,1,2 Hisashi Fukuyama,3 Masakazu Hirota,1 Tatsuo Yamaguchi,4 Kazuo Kitamura,4 Takao Endo,3 Hiroyuki Kanda,1 Takeshi Morimoto,1 Takashi Fujikado1 1Department of Applied Visual Science, Osaka University Graduate School of Medicine, Suita, Osaka, 2Technology Development Department Research and Development Section, Topcon Corporation, Itabashi, Tokyo, 3Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, 4Eye Care Technology Development Department, Product Technology Section, Topcon Corporation, Itabashi, Tokyo, Japan Purpose: The purpose of this study was to develop an algorithm based on region-based segmentation for automated calculations of human cone photoreceptor density of en face images obtained by an adaptive optics scanning laser ophthalmoscope (AOSLO). Subjects and methods: Cone mosaics of 15 eyes of 15 healthy subjects were photographed by a custom-built AOSLO. The cone density was calculated at 0.5, 1.0, and 1.5 mm temporal from the fovea using a region-based segmentation method (RSM) developed in our laboratory. The cone density was also determined by a manual identification method (MIM) and a conventional spatial filtering method (SFM). The cone densities of three eyes of three patients with retinal degeneration were calculated by the three methods and compared to the results from normal eyes. Results: The cone densities in healthy retinas determined by the RSM at 0.5, 1.0, and 1.5 mm temporal from the fovea were 28,436, 21,233, and 13,620 cells/mm2, respectively. These densities were in good agreement with a histological study and with in vivo AOSLO studies. The cone densities determined by RSM were different from those determined by MIM with a difference of 5% in healthy eyes. In eyes with retinal degeneration, with the appropriate threshold-level settings or spatial frequency bandwidth, the cone density measured by MIM was significantly closer to that measured by RSM than by SFM. Conclusion: These results suggest that our method is more stable than conventional methods in cases of non-periodical photoreceptor structures such as the affected retinal area. Our method can be used in the longitudinal follow-up of retinal degenerative diseases and to determine the effect of therapy. Keywords: AOSLO, adaptive optics, cone photoreceptor, photoreceptor density, retinal imaging, image processing

Takashi Fujikado,1 Makoto Saika2 1Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan; 2Research and Development Department of Topcon Corporation, Tokyo, Japan Purpose: To examine the effect of misalignment (decentration and tilt) of intraocular lenses (IOLs) on retinal image quality using a water-immersed model eye with corneal spherical aberration adjusted to the values found in normal human eyes (spherical aberration 0.25 µm; pupil diameter 6 mm).Methods: Three types of IOL holders were prepared. The first was without decentration or tilt, the second had a decentration of 0.5 mm, and the third had a tilt of 5.0°. One spherical IOL and three aspherical IOLs, each with a power of +20 D, were set in the holders and their optical properties (wave front aberration, defocused modulation transfer function, defocused point spread function, and Landolt ring simulations) were compared.Results: Coma aberrations generated by misaligned IOLs were related to the spherical aberration corrective power of the IOLs. Landolt ring simulations show that the depth of focus increased as spherical aberration increased and that the retinal image quality was degraded by increases in coma aberration.Conclusion: Coma aberration was generated by IOLs with a large degree of spherical aberration correction, leading to reduced retinal image quality when the IOL was misaligned. This suggests that, in a clinical setting, the quality of vision might be improved by reducing the degree of coma aberration using IOLs that retain, or minimally correct, spherical aberration. Keywords: coma aberration, decentration, misalignment, spherical aberration, tilt

Takashi Fujikado,1 Sayuri Ninomiya,2 Takuma Kobayashi,2 Asaki Suzaki,3 Mitsuhiko Nakada,3 Kohji Nishida4 1Department of Applied Visual Science, Osaka University Graduate School of Medicine, Suita, 2Itami Chuo Eye Clinic, Itami, 3Menicon, Nagoya, 4Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Japan Purpose: To investigate the effect of low-addition soft contact lenses (CLs) with decentered optical design on the progression of myopia in children in a pilot study.Subjects and methods: Twenty-four Japanese children age 10–16 years with baseline myopia of –0.75 to –3.50 D sphere and ≤1.00 D cylinder were studied. The new CLs were designed to have a nasal decentration with the optical center centered on the line of sight, and with progressive-addition power of +0.5 D peripherally. Monofocal soft CLs were used as controls. A pair of new CLs or control CLs was randomly assigned to the children, and they wore the lenses for 12 months during the first phase. Then, the type of CLs was changed, ie, a crossover design, and the children were observed for another 12 months during the second phase. The end points were changes in axial length and refractive error (spherical equivalent) under cycloplegia.Results: The change of axial length in the new-CL and control-CL groups was not different between 12 months and baseline, the change of axial length between 12 months and 1 month in the new-CL group (0.09±0.08 mm) was significantly smaller (47%) than that in the control-CL group (0.17±0.08 mm, P