Diurnal Variations in Ocular Aberrations of Human Eyes

Chakraborty, Ranjay; Read, Scott A.; Collins, Michael J.

doi:10.3109/02713683.2013.841257

Cited by 12 publications

(12 citation statements)

References 64 publications

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“…Here, for practical reasons, a dioptric distance between old corrective state and new best corrected refraction of 0.35 D was chosen for previous spectacle wearers and a dioptric distance of 0.50 D was chosen for non-spectacle wearers. This threshold of change of 0.35 D (and 0.50 D) is above the known diurnal fluctuation [ 42 ] in refractive status and therefore underlining a true change in refraction. A dioptric distance of 0.35 D is equivalent to a change in sphere of 0.35 D or equivalent to a change in cylinder of 0.50 D, both of which constitute a similar influence on visual acuity.…”

Section: Methodsmentioning

confidence: 89%

Biometry and visual function of a healthy cohort in Leipzig, Germany

et al. 2016

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BackgroundCross-sectional survey of ocular biometry and visual function in healthy eyes across the life span of a German population aged 20 to 69 years (n = 218). Subject number in percent per age category reflected the percentage within the respective age band of the population of Leipzig, Germany.MethodsMeasurements obtained: subjective and objective refraction, best-corrected visual acuity, accommodation, contrast sensitivity, topography and pachymetry with Scheimpflug camera, axial length with non-contact partial coherence interferometry, and spectral-domain optical coherence tomography of the retina. Pearson correlation coefficients with corresponding p-values were given to present interrelationships between stature, biometric and refractive parameters or their associations with age. Two-sample T-tests were used to calculate gender differences. The area under the logarithmic contrast sensitivity function (AULCSF) was calculated for the analysis of contrast sensitivity as a single figure across a range of spatial frequencies.ResultsThe results of axial length (AL), anterior chamber depth (ACD) and anterior chamber volume (ACV) differed as a function of the age of the participants (rho (p value): AL −0.19 (0.006), ACD −0.56 (< 0.001), ACV-0.52 (< 0.001)). Longer eyes had deeper ACD (AL:ACD 0.62 (< 0.001), greater ACV (AL:ACV 0.65 (< 0.001) and steeper corneal radii (AL:R1ant; R2ant; R1post; R2post 0.40; 0.35; 0.36; 0.36 (all with (< 0.001)). Spherical equivalent was associated with age (towards hyperopia: 0.34 (< 0.001)), AL (−0.66 (< 0.001)), ACD (−0.52 (< 0.001)) and ACV (−0.46 (< 0.001)). Accommodation was found lower for older subjects (negative association with age, r = −0.82 (< 0.001)) and contrast sensitivity presented with smaller values for older ages (AULCSF −0.38, (< 0.001)), no change of retinal thickness with age. 58 % of the study cohort presented with a change of refractive correction above ±0.50 D in one or both eyes (64 % of these were habitual spectacle wearers), need for improvement was present in the young age-group and for older subjects with increasing age.ConclusionBiometrical data of healthy German eyes, stratified by age, gender and refractive status, enabled cross-comparison of all parameters, providing an important reference database for future patient-based research and specific in-depth investigations of biometric data in epidemiological research.Trial registrationClinicalTrials.gov # NCT01173614 July 28, 2010

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Section: Methodsmentioning

confidence: 89%

Biometry and visual function of a healthy cohort in Leipzig, Germany

et al. 2016

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“…In previous research, the corneal thickness [ 36 ], axial length, and intraocular pressure [ 37 ] showed diurnal changes in human eyes without orthokeratology treatment. Chakraborty et al [ 38 ] indicated that ocular spherical aberration underwent statistically significant diurnal variation, i.e., spherical aberration was positive during the day and gradually became more negative toward the later afternoon/evening. They also found that the anterior corneal curvature was the flattest in the morning and gradually became steeper throughout the day, which led to a significant myopic refractive shift in spherical equivalent refraction later in the day, but it had an apparent paradoxical relationship with the fluctuation in axial length [ 27 ] (the longest axial length during the day and the shortest at night).…”

Section: Discussionmentioning

confidence: 99%

Changes and Diurnal Variation of Visual Quality after Orthokeratology in Myopic Children

Guo

Jin

Pan

et al. 2018

Journal of Ophthalmology

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Purpose To assess the changes and the diurnal variation of visual quality after orthokeratology in myopic children. Methods Forty-four eyes of 22 subjects with a mean age of 10.55 ± 1.53 years (8 to 14 years) were enrolled in this prospective study. Their spherical equivalent ranged from −1.25 to −4.25 diopters (D) and astigmatism was less than 1.00 D. Parameters including corneal curvature, ocular objective scatter index (OSI), the modulation transfer function (MTF), root mean square of ocular and corneal wavefront aberrations, and contrast sensitivity function (CSF) were measured before and at two time points during the same day after 1 month of orthokeratology. Results After orthokeratology, uncorrected visual acuity (UCVA) and spherical equivalent were significantly improved from baseline (P < 0.001), and their diurnal variation was not significant (P=0.083, 0.568). OSI increased from 0.29 ± 0.15 to 0.65 ± 0.31 (P < 0.001). MTF decreased significantly (P < 0.01). Corneal curvature and ocular total aberration decreased (P < 0.001), while the ocular and corneal higher-order aberration increased significantly (P < 0.01). The CSF under photopic condition decreased at 3 cpd (P=0.006) and increased at 18 cpd (P=0.012). The diurnal variation of CSF at 18 cpd under mesopic and high glare conditions and at 12 cpd under photopic condition was significant (P=0.002, 0.01, 0.017). Conclusions Orthokeratology can effectively improve UCVA and high spatial frequency CSF by decreasing the low-order aberrations. However, MTF and CSF at low spatial frequency decreased because of the increase of intraocular scattering and high-order aberrations. Meanwhile, CSF at high spatial frequency fluctuates significantly at two times during the same day after 1 month orthokeratology.

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“…A small reduction in corneal power vector J0 (astigmatism at 90°/180°) was observed throughout the day (an increase in ATR astigmatism of around 0.02 D for a 5.5 mm pupil) along with a small, but statistically significant reduction in the J45 power vector (astigmatism at 45°/135°). Chakraborty et al . in a study of 30 young adults observed only small changes in horizontal/vertical and oblique ocular astigmatic power vectors, suggesting only slight fluctuations in ocular astigmatism throughout the day (mean amplitude of change: J0 = 0.11 ± 0.04 D and J45 = 0.08 ± 0.05 D, which equates to ~0.25 D amplitude of cylinder variability over the course of the day).…”

Section: The Clinical Correction Of Astigmatismmentioning

confidence: 95%

The visual and functional impacts of astigmatism and its clinical management

Read

Vincent

Collins

2014

Ophthalmic Physiologic Optic

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Purpose: To provide a comprehensive overview of research examining the impact of astigmatism on clinical and functional measures of vision, the short and longer term adaptations to astigmatism that occur in the visual system, and the currently available clinical options for the management of patients with astigmatism. Recent findings: The presence of astigmatism can lead to substantial reductions in visual performance in a variety of clinical vision measures and functional visual tasks. Recent evidence demonstrates that astigmatic blur results in short-term adaptations in the visual system that appear to reduce the perceived impact of astigmatism on vision. In the longer term, uncorrected astigmatism in childhood can also significantly impact on visual development, resulting in amblyopia. Astigmatism is also associated with the development of spherical refractive errors. Although the clinical correction of small magnitudes of astigmatism is relatively straightforward, the precise, reliable correction of astigmatism (particularly high astigmatism) can be challenging. A wide variety of refractive corrections are now available for the patient with astigmatism, including spectacle, contact lens and surgical options. Conclusion: Astigmatism is one of the most common refractive errors managed in clinical ophthalmic practice. The significant visual and functional impacts of astigmatism emphasise the importance of its reliable clinical management. With continued improvements in ocular measurement techniques and developments in a range of different refractive correction technologies, the future promises the potential for more precise and comprehensive correction options for astigmatic patients.

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Diurnal Variations in Ocular Aberrations of Human Eyes

Cited by 12 publications

References 64 publications

Biometry and visual function of a healthy cohort in Leipzig, Germany

Biometry and visual function of a healthy cohort in Leipzig, Germany

Changes and Diurnal Variation of Visual Quality after Orthokeratology in Myopic Children

The visual and functional impacts of astigmatism and its clinical management

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