Biomedical subjects

Tae Moon Jeong

Publications and source records attributed to Tae Moon Jeong.

4 recordsLinked to original sources

PubMed2007

Method of reconstructing wavefront aberrations by use of Zernike polynomials in radial shearing interferometers.

A novel method of reconstructing wavefront aberrations by use of Zernike polynomials for radial shearing interferometers is discussed. This method uses matrix formalism to calculate the Zernike coefficients of a wavefront under test and shows the validity of reconstructing an arbitrary wavefront aberration from an interferogram taken by a radial shearing interferometer. We also propose a new interferometer setup to determine the shape and the direction (concave or convex) of wavefront aberration in a single measurement.

Journal Article↗

PubMed2005

Generalized ray-transfer matrix for an optical element having an arbitrary wavefront aberration.

A generalized ray-transfer matrix for describing the action of an optical element having an arbitrary wavefront aberration is obtained. In this generalized ray-transfer matrix, the action of the aberrated optical element is represented by the product of radial ray-transfer matrices and tangential ray-transfer matrices. The refraction angle of an incident ray is calculated from the gradient of the wavefront aberration at the point of incidence, and the radial and tangential ray-transfer matrices directly use the gradient as a matrix component. To show the validity of the generalized ray-transfer matrix, intercept heights from a spot diagram are calculated with the generalized ray-transfer matrix and compared with those calculated with commercial ray-tracing software.

Journal Article↗

PubMed2005

Measurement of wave-front aberration in soft contact lenses by use of a Shack-Hartmann wave-front sensor.

Lower- and higher-order wave-front aberrations of soft contact lenses were accurately measured with a Shack-Hartmann wave-front sensor. The soft contact lenses were placed in a wet cell filled with lens solution to prevent surface deformation and desiccation during measurements. Aberration measurements of conventional toric and multifocal soft contact lenses and a customized soft contact lens have proved that this method is reliable. A Shack-Hartmann wave-front sensor can be used to assess optical quality of both conventional and customized soft contact lenses and to assist in enhancing lens quality control.

Algorithms↗

PubMedDate not supplied

Vision improvement by correcting higher-order aberrations with phase plates in normal eyes.

PURPOSE: To psychophysically demonstrate vision improvement when correcting higher-order aberrations with phase plates in normal eyes. METHODS: The wavefront aberrations of three nonsurgical normal eyes were measured with a Shack-Hartmann wavefront sensor. With these measured aberrations, phase plates were fabricated using a lathing technique. Theoretical improvement in retinal image quality was estimated by calculating the optical modulation transfer functions under the white light condition. Visual acuity measurements were also conducted to demonstrate improvement in visual performance after correcting higher-order aberrations with the phase plate. In this visual acuity measurement, a tumbling "E" with high (100%) and low (10%) contrast was used. RESULTS: The phase plate reduced the higher-order root mean square (RMS) wavefront error from 0.39 +/- 0.09 to 0.15 +/- 0.02 microm (mean +/- standard deviation from three eyes) for a 6-mm pupil. With the phase plate, retinal image quality based on the volume of modulation transfer function under 60 cycles per degree (c/deg) was improved by a factor of 1.8 +/- 0.4 over that of the eyes with spherocylindrical correction only. Average improvement in visual acuity achieved by correcting the higher-order aberration was 0.23 lines with high-contrast letters and 1.12 lines with low-contrast letters. All subjects reported subjective improvement in image quality of the letter with the phase plate. CONCLUSION: The phase plate effectively corrected the higher-order aberrations in normal eyes. As a result, both retinal image quality and visual acuity especially with the low-contrast letters were improved. This study demonstrated the feasibility of correcting higher-order aberrations and improving vision with customized optics.

Adult↗