scholarly journals Theoretical Effect of Coma and Spherical Aberrations Translation on Refractive Error and Higher Order Aberrations

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 116
Author(s):  
Samuel Arba-Mosquera ◽  
Shwetabh Verma ◽  
Shady T. Awwad
Keyword(s):  
Refractive Error ◽  
Pupil Diameter ◽  
Computer Software ◽  
Quantitative Relationship ◽  
Higher Order ◽  
Visual Axis ◽  
Higher Order Aberrations ◽  
Pupil Center ◽  
Corneal Shape ◽  
The Relationship

(1) Background: The purpose of the study is to present a simple theoretical account of the effect of translation of coma and spherical aberrations (SA) on refractive error and higher order aberrations. (2) Methods: A computer software algorithm was implemented based on previously published methods. The effect of translation (0 to +1 mm) was analyzed for SA (0 to +2 µm) and coma (0 to +2 µm) for a circular pupil of 6 mm, without any rotation or scaling effect. The relationship amongst Zernike representations of various aberrations was analyzed under the influence of translation. (3) Results: The translation of +0.40 µm of SA (C[4,0]) by +0.25 mm with a pupil diameter of 6mm resulted in induction of tilt (C[1,1]), −0.03D defocus (C[2,0]), +0.03D astigmatism (C[2,2]) and +0.21 µm coma (C[3,1]). The translation of +0.4 µm of coma (C[3,1]) by +0.25 mm with a pupil diameter of 6 mm resulted in induction of tilt (C[1,1]), −0.13D defocus (C[2,0]) and +0.13D astigmatism (C[2,2]). A theoretical quantitative relationship between SA, coma, astigmatism and defocus is presented under the influence of translation. (4) Conclusion: The results can act as a guide for the clinician, in order to readily assess theoretical impact of wavefront map translation from pupil center to the visual axis. The resultant refractive coupling has to be taken into consideration especially when treating eyes with an abnormal corneal shape and/or large pupil center to corneal vertex chord.

Relationship between Higher Order Aberrations and Astigmatism in Hyperopic Amblyopia

The Eye ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 27-32
Author(s):  
Sh. A. Mukhanov
Keyword(s):  
Visual Acuity ◽  
Treatment Success ◽  
Higher Order ◽  
The Other ◽  
Complex Treatment ◽  
Higher Order Aberrations ◽  
Significant Difference ◽  
The Relationship ◽  
Decrease In Visual Acuity

Aim. To study the dynamics of changes in the values of higher order aberrations in amblyopia treatment and the correlation between higher-order aberrations and astigmatism in patients with hyperopic amblyopia.Methods. This cohort prospective study included 36 patients (36 eyes) with refractive amblyopia aged 4 to 16 years. All patients had anisometropia: emmetropia in one eye and hyperopic astigmatism combined with refractive amblyopia of varying degrees in the other eye. Patients were divided into two groups depending on the degree of astigmatism. Astigmatism greater than 1.5 D was detected in 20 patients (55.5%) and astigmatism less than 1.5 D was detected in 16 patients (44.5%). All patients underwent a complex treatment, including twenty half-hour sessions of videocomputer autotraining using “Amblyotron” device during 20 days, in addition to constant wearing of glasses. Higher order aberrations were measured using the WaveScan Wavefront System aberrometer at the first visit and at 3-, 6 - and 12-month follow-up. A correlation analysis was performed to assess the relationship between higher order aberrations and astigmatism.Results. There was a statistically significant difference in treatment success between groups with high and low astigmatism. In both groups, higher order aberrations were reduced during the treatment of amblyopia. When comparing the two groups, a significant difference in coma was found at 12-month follow-up (p = 0.043). At 12-month follow-up, coma showed a statistically significant correlation with astigmatism, and a stronger correlation with astigmatism was found in the group of patients with high astigmatism.Conclusions. In patients with refractive amblyopia associated with astigmatism, the decrease in visual acuity is directly dependent on the values of higher-order aberrations, especially on the values of coma, which should be considered as the cause of the development of amblyopia.

scholarly journals Higher order aberrations, refractive error development and myopia control: a review

2019 ◽  
Vol 103 (1) ◽  
pp. 68-85 ◽  
Author(s):  
Rohan PJ Hughes ◽  
Stephen J Vincent ◽  
Scott A Read ◽  
Michael J Collins
Keyword(s):  
Refractive Error ◽  
Higher Order ◽  
Higher Order Aberrations ◽  
Myopia Control

scholarly journals The Effect of the Degree of Astigmatism on Optical Quality in Children

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Jing Gao ◽  
Xiao-xia Wang ◽  
Lin Wang ◽  
Yuan Sun ◽  
Rui-fen Liu ◽  
...  
Keyword(s):  
Pupil Diameter ◽  
Objective Evaluation ◽  
Optical Quality ◽  
Higher Order ◽  
Optical Parameters ◽  
Inclusion Criteria ◽  
Higher Order Aberrations ◽  
Evaluation Parameters ◽  
Important Objective ◽  
High Order Aberrations

Purpose. To investigate the effect of the degree of astigmatism on optical quality in children. The important objective evaluation parameters we focus on include the RMS of the high-order aberrations, MTF, and PSF. Methods. The children, age ranging from 7 to 10 years old, underwent an optometry examination. Fifty-nine children who met the inclusion criteria were divided into three groups: A (1.0 D ≤ astigmatism < 2.0 D), B (2.0 D ≤ astigmatism < 3.0 D), and C (3.0 D ≤ astigmatism < 4.0 D). The OPD-SCAN-III aberrometer was used to measure PSF, MTF, and other optical parameters. Total higher-order aberrations, total coma aberrations, total spherical aberrations, and total trefoil aberrations corresponding to the RMS value, the AR value of MTF, and the SR value of PSF with a 4 mm pupil diameter were assessed. Results. RMS-HO, RMS-T.Coma, RMS-T.Tre, and RMS-T.Sph in the three groups were significantly increased with increasing the degree of astigmatism, while there were no significant differences in RMS-T.Sph between the groups. The AR value and the SR value decreased with increasing degree of astigmatism, and there were significant differences in the AR value and the SR value. Conclusion. Astigmatism has a significant influence on the higher-order aberrations, MTF, and PSF in the children. The effect of astigmatism value on the optical quality is mainly reflected in the change in these three parameters.

scholarly journals Contrast sensitivity and higher-order aberrations in Keratoconus subjects

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Einat Shneor ◽  
David P. Piñero ◽  
Ravid Doron
Keyword(s):  
Contrast Sensitivity ◽  
Corneal Thickness ◽  
Higher Order ◽  
Spearman Correlation ◽  
Higher Order Aberrations ◽  
Good Visual Acuity ◽  
Spatial Frequencies ◽  
Significant Difference ◽  
The Relationship ◽  
Corneal Tomography

AbstractThis study analyzes the relationship between contrast-sensitivity and higher-order aberrations (HOA) in mild and subclinical-keratoconus in subjects with good visual-acuity (VA). Keratoconus group (including subclinical-keratoconus) and controls underwent autokeratometry, corneal-tomography, autorefraction and HOA measurement. Contrast-sensitivity was tested using a psychophysical two-alternative forced-choice Gabor patches in three blocks (6, 9, 12 cycles/deg). Controls were compared to the keratoconus group and to a keratoconus subgroup with VA of 0.00 LogMar group ("keratoconus-0.00VA"). Spearman correlation tested association between HOA and contrast-sensitivity. Twenty-two keratoconus subjects (38 eyes: 28 keratoconus, 10 subclinical-keratoconus, 20 keratoconus-0.00VA) and 35 controls were included. There was a significant difference between control and keratoconus, and between control and keratoconus-0.00VA, for keratometry, cylinder, thinnest and central corneal thickness (p < 0.001). Controls showed lower HOA and higher contrast-sensitivity for all spatial-frequencies (p < 0.001). Most HOA were negatively correlated with contrast-sensitivity for all spatial-frequencies for keratoconus group and for 9 and 12 cycles/deg for keratoconus-0.00VA. Keratoconus subjects with good VA showed reduction in contrast-sensitivity and increased HOAs compared to controls. HOA and contrast-sensitivity are inversely correlated in subjects with mild keratoconus despite good VA. This suggests that the main mechanism underlying the decreased vision quality in keratoconus is the increase of HOA.

scholarly journals Higher order aberrations of the eye: Part two

2016 ◽  
Vol 75 (1) ◽  
Author(s):  
Marsha Oberholzer ◽  
Wayne D.H. Gillan ◽  
Alan Rubin
Keyword(s):  
Pupil Diameter ◽  
Tear Film ◽  
Crystalline Lens ◽  
Higher Order ◽  
Refractive Errors ◽  
Measuring Apparatus ◽  
Higher Order Aberrations ◽  
Wavefront Aberrations ◽  
Human Eye

This article is the second in a series of two articles, which provides a discussion of the factors that may possibly contribute to variable results when wavefront aberrations of the human eye are measured. Some of the factors discussed in this article are the influences that refractive errors (specifically myopia and astigmatism), pupil diameter, accommodation of the crystalline lens, age, mydiatric drops and the integrity of the tear film may have on these wavefront measurements. The first article in the series explained the general principles of higher order aberrations (HOAs), as well as HOAs of importance in the eye and the measuring apparatus used to measure HOAs of the eye.Keywords: wavefront aberrations; aberrometry

scholarly journals Influence of Overhanging Bleb on Corneal Higher-Order Aberrations after Trabeculectomy

2021 ◽  
Vol 11 (1) ◽  
pp. 177
Author(s):  
Yu Mizuno ◽  
Kazuyuki Hirooka ◽  
Yoshiaki Kiuchi
Keyword(s):  
Mitomycin C ◽  
Pupil Diameter ◽  
Glaucoma Surgery ◽  
Higher Order ◽  
Control Group ◽  
Higher Order Aberrations ◽  
Ocular Surgery ◽  
Conjunctival Flap ◽  
Single Center Study ◽  
History Of

Recent advances in ocular aberrometry have revealed that ocular surgery increases ocular and corneal higher-order aberrations. This retrospective single-center study aimed to examine the effects of the overhanging bleb on corneal higher-order aberrations using a wavefront analyzer. We included 61 eyes from 50 patients with overhanging bleb after trabeculectomy with a fornix-based conjunctival flap using mitomycin C (overhanging bleb group) and 65 eyes from 54 glaucoma patients with no history of glaucoma surgery (control group). Corneal higher-order aberrations (total higher-order aberrations, coma aberrations, coma-like aberrations, spherical aberrations, and spherical-like aberrations) on a 4 mm pupil diameter were measured using the TOPCON KR-1W wavefront analyzer. Corneal coma aberrations were higher in the overhanging bleb group than in the control group (0.16 ± 0.13 μm and 0.10 ± 0.05 μm, respectively; p = 0.042). Corneal coma-like aberrations were also higher in the overhanging bleb group than in the control group (0.31 ± 0.32 μm and 0.16 ± 0.09 μm, respectively; p = 0.022). With an increasing ratio of cornea covered by the bleb to the entire cornea, all corneal higher-order aberrations increased except for corneal coma-like aberrations. Overhanging bleb after trabeculectomy with a fornix-based conjunctival flap using mitomycin C and its size influenced corneal higher-order aberrations.

scholarly journals Improvements in Optical Characteristics after Excision of an Overhanging Bleb Developed following Trabeculectomy

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Yu Mizuno ◽  
Atsushi Hirota ◽  
Kazuyuki Hirooka ◽  
Yoshiaki Kiuchi
Keyword(s):  
Visual Acuity ◽  
Pupil Diameter ◽  
Higher Order ◽  
Higher Order Aberrations ◽  
Case Presentation ◽  
Conjunctival Flap ◽  
Corrected Visual Acuity ◽  
Before And After ◽  
Higher Order Aberration ◽  
Best Corrected Visual Acuity

Introduction. To examine the corneal total higher-order aberrations before and after the excision of an overhanging bleb that developed following trabeculectomy. Case Presentation. Two patients who developed overhanging blebs following trabeculectomy with a fornix-based conjunctival flap using mitomycin C (MMC) were assessed. We measured the corneal total higher-order aberrations for a 4 mm pupil diameter using the TOPCON KR-1W wavefront analyzer and the visual acuity before and after bleb excision. The corneal total higher-order aberration (HOA) improved from 0.50 μm to 0.38 μm in case 1 and from 0.59 μm to 0.49 μm in case 2 after bleb excision. The intraocular pressure was identical before and after bleb excision in both cases. No significant changes in the best-corrected visual acuity (BCVA) were noted in case 1; however, BCVA was improved from 20/25 to 20/20 in case 2. Both cases showed improvements in the symptoms of dysesthesia. Conclusion. Excision of the overhanging bleb developed following trabeculectomy may have beneficial possibility in some cases where corneal total HOA is affected and reduces the symptoms of dysesthesia.

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