Purpose: To evaluate precision of the new Aniseikonia Test based on the Space Eikonometry (ATSE) which we developed.
Methods: Thirty normal subjects without ocular disease except for refractive errors were studied. We simulated 10% overall aniseikonia, 10% horizontal aniseikonia, and 10% vertical aniseikonia with size lenses placed in the optical path of the fully corrected right eye. We measured each aniseikonia three times with the ATSE and the averages were used.
Results: The mean ± standard deviation (SD) aniseikonia determined by the ATSE was 9.62 ± 1.16% with the 10% overall aniseikonia and 9.24 ± 0.89% with the 10% horizontal aniseikonia and 10.40 ± 1.26% with the 10% Vertical aniseikonia.
Conclusions: The ATSE has high accuracy for measurements of aniseikonia, and we recommend its use for quantitative analyses of aniseikonia.
Purpose: To compare horizontal extraocular muscle insertions between children and adults using AS-OCT.
Subjects: Patients who visited Hamamatsu University School of Medicine and healthy volunteers were included. Exclusion criteria are eye deviation > 20 prism diopters (PD), axial length > 28 mm, and prior ocular surgery. Adults ≥ 18 years and children < 18 years old were included.
Method: Horizontal extraocular muscle insertions were measured with AS-OCT (TOMEY SS-1000 CASIA). Axial length and horizontal extraocular muscle insertion from the angle recess were measured and compared.
Results: Axial lengths were significantly shorter in children than in adults (23.71±1.38 mm vs. 25.11±1.29 mm). Distance from angle recess to medial rectus and lateral rectus was comparable between children and adults (4.02±0.46 mm and 5.96±0.50 mm vs. 4.08±0.57 mm and 5.83±0.50 mm, respectively). The horizontal extraocular muscle insertions did not correlate with the age and axial length.
Conclusion: Horizontal extraocular muscle insertion was unrelated to age and axial length in subjects ≥ 4 years old. AS-OCT can measure extraocular muscle insertion noninvasively.
Retinal prostheses electrically stimulate retinas with photoreceptor cell degeneration to evoke a pseudo light sensation (phosphenes). Rectangular pulse electrical stimulation is generally used for retinal prosthesis. In this study, we attempted to determine more effective electrical stimulation parameters by electrophysiologically examining the stimulation efficiency of four stimulation waveform shapes (rectangular, triangular, saw-tooth, and inverse saw-tooth). A stimulation electrode and a return electrode were set on one eyeball of each rat, and a single biphasic, cathodic-first current pulse was applied between the electrodes. The four types of waveforms of equal charge quantity were then compared. Significantly larger neural response amplitudes were observed for the triangular and saw-tooth pulses than for the rectangular pulse, suggesting that electrical stimulation could be applied with a lower electric charge using a triangular and saw-tooth pulses.
Purpose: To examine the relationship between the effect of orthokeratology (Ortho-K) to suppress myopia progression and create higher-order wavefront aberration (HOA) in children.
Methods: This study involved 144 eyes of 72 children followed for 2-years after undergoing Ortho-K, and 3-weeks post Ortho-K. Wavefront aberration after 2-years Ortho-K and objective spherical equivalence (SE) under cycloplegia and axial length (AL) pre Ortho-K, 2-years after Ortho-K, and 3-weeks post Ortho-K was measured. HOA (i.e., coma-like aberration, spherical-like aberration, spherical aberration and total HOA of cornea and ocular 4mm-pupil) and correlation of the HOA and myopia progression was evaluated.
Results: Spherical-like aberration of cornea and change of objective SE were positive correlated (R=0.17, Pearson test). Coma-like, spherical-like, spherical, and total HOA of cornea/ocular and change of AL were negatively correlated (R=-0.20, -0.24, -0.19, -0.23, -0.22, -0.23, -0.21, and -0.23).
Conclusion: Ortho-K increased HOA of cornea and ocular 4mm-pupil in childhood myopia, and suppressed myopia in proportion to highly aberrated optics. HOA increase possibly suppresses myopia.
Purpose: We investigated what kind of fitting adjustment was necessary for Progressive Addition Lens (PAL) improperly fitting example. In addition, we investigated whether improvement of defects by adjustment of fitting can be objectively evaluated.
Methods: The subjects were 137 people who prescribed PAL and who had a fitting defect among patients who had consult again from May 2015 for one year. In that three subjects, we measured objective refraction by SpotTM Vision Screener (Spot vision) before and after the fitting adjustment under PAL wear, and the spherical equivalent (SE) was compared.
Result: 84 people required adjustment of the vertex distance, and also 84 people who required adjustment of the distance fitting point (DFP). Among them, the mean SE of 6 eyes was significant before -0.56±0.44 D, after adjustment -0.33±0.47 D (t test, p=0.0001).
Conclusion: When complaining of PAL trouble, it is important to check the vertex distance and DFP. In addition, it was suggested that spot vision is useful for objective evaluation of improperly fitting cases.