Impact of segmented optical axial length on the performance of intraocular lens power calculation formulas.

Purpose: To investigate the difference between the segmented axial length (AL) and the composite AL on a swept-source optical coherence tomography biometer and to evaluate the subsequent effects on artificial intelligence intraocular lens (IOL) power calculations: the Kane and Hill-RBF 3.0 formulas compared with established vergence formulas.

Setting: National Hospital Organization, Tokyo Medical Center, Japan.

Effect of Segmented Optical Axial Length on the Performance of New-Generation Intraocular Lens Power Calculation Formulas in Extremely Long Eyes.

Purpose: To evaluate the performance of traditional vergence formulas with segmented axial length (AL) compared to traditional composite AL in extremely long eyes, and to determine whether the segmented AL can be extended to the new-generation formulas, including the Barrett Universal II, Emmetropia Verifying Optical 2.0 (EVO2), Hill-RBF 3.0 (Hill3), Kane, and Ladas Super formula (LSF) formulas in extremely long eyes.

Comparison of two one-piece acrylic foldable intraocular lenses: Short-term change in axial movement after cataract surgery and its effect on refraction.

Purpose: To compare the change in intraocular lens (IOL) axial movement, corneal power, and postoperative refraction of eyes implanted with two different single-piece, open loop, acrylic foldable IOLs with planar-haptic design: one IOL with hinges vs. one IOL without hinges. The role of IOL axial movement on short-term refractive shift after cataract surgery was also evaluated.

Preliminary demonstration of a novel intraocular lens power calculation: the O formula.

Purpose: To evaluate the performance of a new formula of intraocular lens (IOL) power calculation (the O formula) based on ray tracing without commonly used parameters, including ultrasound-compatible axial length, keratometry readings, and A-constant.

Setting: Tokyo Medical Center, Tokyo, Japan.

Design: Retrospective consecutive case series.

Case Report: Getting a Peek at the Angle of a Patient with Severe Keratoconus.

Visualization of the iridocorneal angle, which contains the aqueous humor circulatory system and controls intraocular pressure, is important for diagnosing and managing glaucoma; however, the presence of keratoconus, keratoglobus, or severe myopia may enable direct angle visualization without gonioscopy contact lenses or applying a coupling gel. We present the first report of a case in which the iridocorneal angle was viewed directly in an eye with keratoconus using the RetCam without applying gel to the cornea. This method overcame the inability to view the angle directly in a normal eye because of the total internal reflection.

Three-dimensional measurement for spherical and nonspherical shapes of contact lenses.

In recent years, with the development of precise lathe-cutting equipment, special shaped contact lenses (CL) have been crafted. However, while it is possible to manufacture such a lens, its shape evaluation has not been well-established. We conducted a basic optical experiment using special lenses to measure a spherical lens and nonspherical mold.

Measurement algorithm for real front and back curved surfaces of contact lenses.

The optical measurement algorithm for the real front and back surfaces of contact lenses from their center to periphery accurately and simultaneously is proposed. It is an algorithm that makes light incident vertically along the curved surfaces of contact lenses under the condition that the difference of curvature radii between the front and back surfaces is small enough within the NA of the optical probe. For this purpose, we adopted time-domain optical coherence tomography (OCT) with translation and rotation mechanisms.

Change in optical axial length after cataract surgery: segmental method vs composite method.

Purpose: To compare the changes in axial length (AL) obtained after cataract surgery by partial coherence interferometry (PCI), swept-source optical coherence tomography with the composite method (SS-OCT/CM), and SS-OCT with the segmental method (SS-OCT/SM).

Setting: National Hospital Organization, Tokyo Medical Center, Japan.

Design: Retrospective case series.

Comparison of composite and segmental methods for acquiring optical axial length with swept-source optical coherence tomography.

This study compared the optical axial length (AL) obtained by composite and segmental methods using swept-source optical coherence tomography (SS-OCT) devices, and demonstrated its effects on the post-operative refractive errors (RE) one month after cataract surgery. Conventional AL measured with the composite method used the mean refractive index. The segmented-AL method used individual refractive indices for each ocular medium.

Violet Light Transmission is Related to Myopia Progression in Adult High Myopia.

Myopia is increasing worldwide. Although the exact etiology of myopia is unknown, outdoor activity is one of the most important environmental factors for myopia control. We previously reported that violet light (VL, 360-400 nm wavelength), which is abundant in the outdoor environment, suppressed myopia progression for individuals under 20 years of age.

Violet Light Exposure Can Be a Preventive Strategy Against Myopia Progression.

Prevalence of myopia is increasing worldwide. Outdoor activity is one of the most important environmental factors for myopia control. Here we show that violet light (VL, 360-400nm wavelength) suppresses myopia progression.

Prediction of Postoperative Intraocular Lens Position with Angle-to-Angle Depth Using Anterior Segment Optical Coherence Tomography.

Purpose: To evaluate the accuracy of a new formula for predicting postoperative anterior chamber depth (ACD) with preoperative angle-to-angle (ATA) depth using anterior segment (AS) optical coherence tomography (OCT) and to compare it with established methods.

Design: Retrospective consecutive case series.

Participants: Three hundred four eyes (276 patients) implanted with acrylic intraocular lenses (IOLs) were divided randomly into a training set (152 eyes) and a validation set (152 eyes).

Visual Function and Higher-Order Aberrations in Eyes After Corneal Transplantation: How to Improve Postoperative Quality of Vision.

An understanding of corneal optics is important to optimize the visual outcome after eye surgery. Recent advances in the surgical techniques of lamellar keratoplasty have changed the strategies used for corneal transplantation. Lamellar keratoplasty has the advantage of having a lower rate of graft rejection, superior biomechanical properties, and reduced higher-order aberrations (HOAs) compared with penetrating keratoplasty; thus, the use of lamellar keratoplasty has increased over the last 15 years.

Image quality of grating target in model eye when viewed through a small-aperture corneal inlay.

Purpose: To evaluate the quality of the image of a grating target placed in a model eye and viewed through a small-aperture corneal inlay.

Setting: Kyorin Eye Center, Tokyo, Japan.

Design: Experimental study.

Images of intravitreal objects projected onto posterior surface of model eye.

Purpose: To try to recreate the images reported by patients during vitreous surgery in a model eye.

Methods: A fluid-filled model eye with a posterior frosted translucent surface which corresponded to the retina was used. Three holes were made in the model eye through which an endoillumination pipe and intraocular forceps could be inserted.

Peripheral optical quality and myopia progression in children.

Background: To investigate the peripheral optical quality and its relationship with axial elongation, myopic progression in Japanese children.

Methods: Twenty-nine Japanese children, ages 10 to 12 years old, with baseline refraction from +0.75 D to -5.

Quality of image of grating target placed in model eye and observed through toric intraocular lenses.

Purpose: To evaluate the quality of an image of a grating target placed in a model eye and viewed through implanted toric intraocular lenses (IOLs).

Design: Laboratory investigation.

Methods: Toric IOLs, SN6AT5 with a cylinder power of 3.

Age-related changes in spectral transmittance of the human crystalline lens in situ.

Aims: It was the aim of this study to measure spectral transmission of the human crystalline lens in situ.

Method: The crystalline lens was illuminated by one of four light-emitting diodes of different colors. The relative spectral transmittance of the human crystalline lens was measured with the Purkinje-Sanson mirror images over a wide range of ages.

Correlation between contrast sensitivity and higher-order aberration based on pupil diameter after cataract surgery.

Background: The purpose of this study was to evaluate the correlation between contrast sensitivity and calculated higher-order aberrations based on individual natural pupil diameter after cataract surgery.

Methods: This prospective study included 120 eyes from 92 patients who were randomized to receive one of four lenses, including three aspheric lenses (Acrysof SN60WF, Tecnis ZA9000, and Hoya Py60AD) and one spherical lens (Acrysof SN60AT). Contrast sensitivity, higher-order aberrations of the whole eye, and pupil diameter under photopic and mesopic conditions were measured 1 month postoperatively.

Retinal nerve fiber layer retardation measurements using a polarization-sensitive fundus camera.

To measure the retardation distribution of the optic retinal nerve fiber layer (RNFL) from a single image, we have developed a new polarization analysis system that is able to detect the Stokes vector using a fundus camera. The polarization analysis system is constructed with a CCD area image sensor, a linear polarizing plate, a microphase plate array, and a circularly polarized light illumination unit. In this system, the Stokes vector expressing the whole state of polarization is detected, and the influence of the background scattering in the retina and of the retardation caused by the cornea are numerically eliminated.

The contribution of the posterior surface to the corneal aberrations in eyes after keratoplasty.

Purpose: To investigate the contribution of posterior corneal surfaces to higher-order aberrations (HOAs) of the cornea, optical quality, and visual acuity after keratoplasty.

Methods: Corneal topography of anterior and posterior surfaces and pachymetry were conducted using anterior segment optical coherence tomography (AS-OCT) in 40 eyes (10 eyes after penetrating keratoplasty [PK], 10 eyes after deep anterior lamellar keratoplasty [DALK], 10 eyes after Descemet's stripping automated endothelial keratoplasty [DSAEK], and 10 normal eyes). Anterior, posterior, and total corneal HOAs were calculated using ray-tracing and decomposition into Zernike polynomials and were evaluated as root mean square values.

Quality of image of grating target placed in vitreous of isolated pig eyes photographed through different implanted multifocal intraocular lenses.

Purpose: To determine the quality of the image of a grating target placed in the vitreous of isolated pig eyes and photographed through implanted refractive and diffractive multifocal intraocular lenses (IOL).

Methods: Refractive multifocal (NXG1, PY60MV), diffractive multifocal (ZM900, SA60D3) and monofocal (SA60AT, ZA9003) IOL were implanted in the capsular bag of isolated pig eyes. A grating target was placed in the vitreous and photographed through a flat or a wide-field viewing contact lens.