The Role of Back Optic Zone Diameter in Myopia Control with Orthokeratology Lenses

Pauné, Jaume; Fonts, Silvia; Rodríguez, Lina; Queirós, António

doi:10.3390/jcm10020336

Cited by 53 publications

(72 citation statements)

References 59 publications

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“…A recent study showed that a smaller back optic zone diameter for the OK lens would produce a smaller plus power ring diameter on the cornea's front surface. When the plus power ring's horizontal sector was inside the pupil, the mean AL elongation of those subjects was 76% lesser than the subjects who had the plus power ring outside the pupil (Paune et al, 2021). Our study supported this result and found a linear correlation between AL elongation and the amount of Half_x inside the pupil.…”

Section: Discussionsupporting

confidence: 83%

The Spatial Distribution of Relative Corneal Refractive Power Shift and Axial Growth in Myopic Children: Orthokeratology Versus Multifocal Contact Lens

et al. 2021

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PurposeTo determine if the spatial distribution of the relative corneal refractive power shift (RCRPS) explains the retardation of axial length (AL) elongation after treatment by either orthokeratology (OK) or multifocal soft contact lenses (MFCLs).MethodsChildren (8–14 years) were enrolled in the OK (n = 35) or MFCL (n = 36) groups. RCRPS maps were derived by computing the difference between baseline and 12-month corneal topography maps and then subtracting the apex values. Values at the same radius were averaged to obtain the RCRPS profile, from which four parameters were extracted: (1) Half_x and (2) Half_y, i.e., the x- and y-coordinates where each profile first reached the half peak; (3) Sum4 and (4) Sum7, i.e., the summation of powers within a corneal area of 4- and 7-mm diameters. Correlations between AL elongation and these parameters were analyzed by multiple linear regression.ResultsAL elongation in the OK group was significantly smaller than that in the MFCL group (p = 0.040). Half_x and Half_y were also smaller in the OK group than the MFCL group (p < 0.001 each). Half_x was correlated with AL elongation in the OK group (p = 0.005), but not in the MFCL group (p = 0.600). In an analysis that combined eyes of both groups, Half_x was correlated with AL elongation (β = 0.161, p < 0.001).ConclusionsThe OK-induced AL elongation and associated RCRPS Half_x were smaller than for the MFCL. Contact lenses that induce RCRPS closer to the corneal center may exert better myopia control.

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Section: Discussionsupporting

confidence: 83%

The Spatial Distribution of Relative Corneal Refractive Power Shift and Axial Growth in Myopic Children: Orthokeratology Versus Multifocal Contact Lens

et al. 2021

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“…Further, changes described here may be specific to the BE lens design and corneal changes may be different for lenses of other designs, particularly in relation to the reverse curve parameters and back optic zone diameter. Recent studies have also demonstrated reduced orthokeratology lens back optic diameters can decrease treatment zone diameters 40 , 41 .…”

Section: Discussionmentioning

confidence: 99%

Predicting corneal refractive power changes after orthokeratology

Kang

Maseedupally

Gifford

et al. 2021

Sci Rep

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This study aimed to characterise corneal refractive power (CRP) changes along the principal corneal meridians during orthokeratology (OK). Nineteen myopes (mean age 28 ± 7 years) were fitted with OK lenses in both eyes. Corneal topography was captured before and after 14 nights of OK lens wear. CRP was calculated for the central 8 mm cornea along the horizontal and vertical meridians. The central-paracentral (CPC) power ratio was calculated as the ratio between maximum central and paracentral CRP change from individual data. There was a significant reduction in CRP at all locations in the central 4 mm of the cornea (all p < 0.001) except at 2 mm on the superior cornea (p = 0.071). A significant increase in CRP was evident in the paracentral zone at 2.5, 3 and 3.5 mm on the nasal and superior cornea and at 3.5 and 4 mm on the temporal cornea (all p < 0.05). No significant change in CRP was measured in the inferior cornea except decreased CRP at 2.5 mm (p < 0.001). CPC power ratio in the nasal and temporal paracentral regions was 2.49 and 2.23, respectively, and 2.09 for both the inferior and superior paracentral corneal regions. Our results demonstrates that OK induced significant changes in CRP along the horizontal and vertical corneal meridians. If peripheral defocus changes are inferred from corneal topography, this study suggests that the amount of myopia experienced on the peripheral retina was greater than twice the amount of central corneal power reduction achieved after OK. However, this relationship may be dependent on lens design and vary with pupil size. CPC power ratios may provide an alternative method to estimate peripheral defocus experienced after OK.

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“…A short-term study of different compression factors found that no significant changes in eye parameters were found between the different design lenses [ 28 ]. However, OK lens of smaller back optic zone diameter achieved better curative effect [ 29 , 30 ]. Further investigations will be need to make OK lens more effective in myopia control.…”

Section: Discussionmentioning

confidence: 99%

Factors associated with faster axial elongation after orthokeratology treatment

Liu

et al. 2022

BMC Ophthalmol

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Background To study the baseline factors that related to faster axial elongation after orthokeratology (OK) treatment and the characteristics of cases with axial length decrease in a group of myopia children. Methods This is a retrospective study. The records of 73 children who had wear OK lens for at least one year were reviewed. Only the data of right eyes were included. Baseline data included: age, gender, parental myopia, refractive error, corneal power, central corneal thickness, axial length and anterior chamber depth. Corneal power, central corneal thickness, anterior chamber depth and axial length after one-year of OK lens wear were also collected. The related factors affecting axial length change were analyzed. A comparison was made on the cases of axial length increase and axial length decrease. Results Of the 73 eyes, axial length increased by 0.18 ± 0.17 mm (P < 0.001) after one year of OK lens wear. Correlation analysis showed that one-year axial length change was negatively correlated with age and positively correlated with the parental myopia and baseline myopia. Stepwise multiple linear regression analysis showed that the factors associated with faster axial elongation were lower baseline myopic spherical equivalent (P = 0.018), higher parental myopia degree (P = 0.026), and younger age at the onset of lens wear. (P = 0.039). Nine eyes showed negative axial growth (−0.06 ± 0.04 mm), and had older initial age of lens wear, higher baseline myopic spherical equivalent, and lager baseline corneal power, when compared with cases of axial length increase. Conclusions Myopia children with lower baseline myopic spherical equivalent, younger initial age and higher parental myopia had faster axial elongation after orthokeratology treatment. More aggressive treatment should be considered. In children with slow axial elongation, OK lens wear may lead to negative axial growth. Whether there are reasons other than central corneal thinning and choroidal thickening needs further study.

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The Role of Back Optic Zone Diameter in Myopia Control with Orthokeratology Lenses

Cited by 53 publications

References 59 publications

The Spatial Distribution of Relative Corneal Refractive Power Shift and Axial Growth in Myopic Children: Orthokeratology Versus Multifocal Contact Lens

The Spatial Distribution of Relative Corneal Refractive Power Shift and Axial Growth in Myopic Children: Orthokeratology Versus Multifocal Contact Lens

Predicting corneal refractive power changes after orthokeratology

Factors associated with faster axial elongation after orthokeratology treatment

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