Central and Paracentral Corneal Curvature Changes During Orthokeratology

Maseedupally, Vinod; Gifford, Paul; Lum, Edward; Swarbrick, Helen A.

doi:10.1097/opx.0000000000000039

Cited by 48 publications

(43 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…But Chen et al recently reported variations in the Q-values for different regions of the anterior corneal surface, indicating that a single value could not precisely reflect corneal Q-value. [9,17] Consistent with this finding, we found that the average Q-value was comparable between eyes with and without decentration, but the corneal Q-value differences between nasal–temporal and superior–inferior quadrants were significantly higher in eyes with lens decentration, which indicated a more aspheric surface of the temporal and inferior quadrants. Importantly, this finding explains why orthokeratology lens prefer to shift to the temporal and inferior quadrants.…”

Section: Discussionsupporting

confidence: 80%

Predictive role of corneal Q-value differences between nasal–temporal and superior–inferior quadrants in orthokeratology lens decentration

Yang

Xie

et al. 2017

Medicine

View full text Add to dashboard Cite

Background:To investigate the association between pretreatment corneal parameters and orthokeratology lens decentration.Methods:This retrospective study included a total of 108 eyes in 60 myopia patients, who were divided into a lens-decentration and a control group. Various pretreatment corneal parameters were analyzed by receiver operating characteristic curves (ROC curves), including corneal horizontal and vertical curvatures, diopter, corneal eccentricity (E-value), asphericity (Q-value), diameter, and astigmatism, to establish a reliable predictive model for orthokeratology lens decentration.Results:The temporal and inferior quadrants are preferential sides for lens decentration, which was associated with the occurrence of complications such as ghosting and corneal epithelial staining. By further analysis, we revealed lower corneal horizontal curvature and much higher corneal Q-value differences between the nasal–temporal and superior–inferior quadrants in the lens-decentration group compared to the control group (P < 0.05). ROC curve analysis showed that the sum of Q-value differences between the nasal–temporal and superior–inferior quadrants was more sensitive than any other corneal parameters in predicting lens decentration, with an area under the curve of 0.778 and a truncation point of 0.3 (P < 0.001).Conclusion:The sum of pretreatment corneal Q-value differences between nasal–temporal and superior–inferior quadrants is a convenient and reliable predictor for orthokeratology lens decentration.

show abstract

Section: Discussionsupporting

confidence: 80%

Predictive role of corneal Q-value differences between nasal–temporal and superior–inferior quadrants in orthokeratology lens decentration

Yang

Xie

et al. 2017

Medicine

View full text Add to dashboard Cite

show abstract

“…[1] As an external object placed against the front surface of the cornea, orthokeratology lens is expected to cause certain changes in the anterior segment parameters, such as corneal curvature and thickness. Previous studies have reported flattened corneal curvature, [2,3] reduced central corneal thickness (CCT), and increased thickness in the mid-peripheral cornea after orthokeratology. [4,5] There are also studies showing a thinned central epithelial layer [6,7] and thickened corneal stromal layer [8,9] after wearing orthokeratology lens.…”

Section: Introductionmentioning

confidence: 99%

The relationship between corneal biomechanics and anterior segment parameters in the early stage of orthokeratology

et al. 2017

View full text Add to dashboard Cite

To investigate the relationship between corneal biomechanics and anterior segment parameters in the early stage of overnight orthokeratology.Twenty-three eyes from 23 subjects were involved in the study. Corneal biomechanics, including corneal hysteresis (CH) and corneal resistance factor (CRF), and parameters of the anterior segment, including corneal curvature, central corneal thickness (CCT), and corneal sublayers’ thickness, were measured at baseline and day 1 and 7 after wearing orthokeratology lens. One-way analysis of variance with repeated measures was used to compare the longitudinal changes and partial least squares linear regression was used to explore the relationship between corneal biomechanics and anterior segment parameters.At baseline, CH and CRF were positively correlated with CCT (r = 0.244, P = .008 for CH; r = 0.249, P < .001 for CRF), central stroma thickness (CST) (r = 0.241, P = .008 for CH; r = 0.244, P = .002 for CRF) and central Bowman layer thickness (CBT) (r = 0.138, P = .039 for CH; r = 0.171, P = .006 for CRF). Both CH and CRF significantly decreased from day 1 after orthokeratology. The corneal curvature and the epithelium thickness also significantly decreased, while the stromal layer thickened significantly from day 1 after orthokeratology. There was no correlation between the changes of corneal biomechanics and anterior segment parameters at day 1 and 7 after orthokeratology.While corneal biomechanics were positively correlated with CCT, CST, and CBT, the changes of CH and CRF were not correlated with the changes of corneal curvature, CCT, and corneal sublayers’ thickness in the early stage of orthokeratology in our study.

show abstract

“…A number of studies have suggested that various ocular parameters (corneal thickness in particular) are modifiable or predictive values for myopic reduction in orthokeratology [212223242526]. In 2000, Lui and Edwards [21] reported that CCT is the most predictive value of myopic reduction based on the results of a randomized controlled clinical trial involving 14 subjects who wore orthokeratology lenses during the daytime.…”

Section: Discussionmentioning

confidence: 99%

Effectiveness of Toric Orthokeratology in the Treatment of Patients with Combined Myopia and Astigmatism

Lyu

Hwang

Kim

et al. 2016

Korean J Ophthalmol

View full text Add to dashboard Cite

PurposeThe purpose of this multi-institute, single-group clinical trial was to evaluate the effectiveness and safety of toric orthokeratology lenses for the treatment of patients with combined myopia and astigmatism.MethodsA total of 44 patients were included in this clinical trial. The patients ranged in age from 7 to 49 years, with myopia of -0.75 to -6.0 diopters (D) and astigmatism of 1.25 to 4.0 D. After excluding 21 subjects, 23 subjects (39 eyes) were analyzed after toric orthokeratology lens use. The subjects underwent ophthalmologic examination after 1 day and 1, 2, 3, and 4 weeks of wearing overnight toric orthokeratology lenses.ResultsA total of 19 subjects (31 eyes) completed the trial after five subjects (eight eyes) dropped out. In the patients who completed the study by wearing lenses for 4 weeks, the myopic refractive error decreased significantly by 2.60 ± 2.21 D (p < 0.001), from -3.65 ± 1.62 to -1.05 ± 1.64 D. The astigmatic refractive error were also significantly decreased by 0.63 ± 0.98 D (p = 0.001), from 2.07 ± 0.83 to 1.44 ± 0.99 D. The mean uncorrected and corrected visual acuities before wearing the lenses were 2.14 ± 0.80 logarithm of the logMAR (logMAR) and 0.05 ± 0.13 logMAR, respectively, which changed to 0.12 ± 0.30 logarithm of the logMAR (p < 0.001) and 0.01 ± 0.04 logMAR (p = 0.156) after 4 weeks. No serious adverse reactions were reported during the clinical trial.ConclusionsOur results suggest that toric orthokeratology is an effective and safe treatment for correcting visual acuity in patients with combined myopia and astigmatism.

show abstract

Central and Paracentral Corneal Curvature Changes During Orthokeratology

Abstract: OK induces non-uniform corneal changes to the central and paracentral regions. This non-uniformity may influence peripheral refraction profiles reported with OK that have been suggested to be influential in myopia control.

Cited by 48 publications

References 31 publications

Predictive role of corneal Q-value differences between nasal–temporal and superior–inferior quadrants in orthokeratology lens decentration

Predictive role of corneal Q-value differences between nasal–temporal and superior–inferior quadrants in orthokeratology lens decentration

The relationship between corneal biomechanics and anterior segment parameters in the early stage of orthokeratology

Effectiveness of Toric Orthokeratology in the Treatment of Patients with Combined Myopia and Astigmatism

Contact Info

Product

Resources

About