Background To investigate whether the treatment zone size (TZS) and treatment zone decentration (TZD) will affect the axial elongation in myopic children undergoing orthokeratology treatment. Methods A self-controlled retrospective study was conducted on 352 children who met the inclusion criteria. Axial length was measured before and at 12 months after the initial lens wear. Corneal topography was measured at baseline and at each follow-up after lens wear. The Corneal topography obtained from the 12-month visit was used to quantify TZS and TZD for each subject. Cycloplegic refraction was required for all children before fitting the orthokeratology lenses. Results Axial elongation was significantly associated with age, baseline spherical equivalent (SE), TZS, and TZD with univariate linear regression. In groups with both small and large TZS, axial elongation was significantly decreased with large TZD (both P < 0.01). In groups with both small and large TZD, axial elongation was significantly decreased with small TZS (P = 0.03 for small TZD, P = 0.01 for large TZD). Age, SE, and TZD were significantly associated with axial elongation in multiple regression (all P < 0.01). Conclusion Relatively smaller TZS and larger TZD may be beneficial in slowing myopia progression in children with orthokeratology treatment.

PurposeWe present a new method for analyzing relative corneal refractive power (RCRP) in children undergoing orthokeratology and explore its potential association to effective myopic controlMethodsA total of 55 children aged 8 to 12 years participated in the study. Axial growth was calculated as the difference in axial length before and 1 year after orthokeratology. Growth <0.30 mm was considered as effective control. Corneal topography was obtained before and 4 months after lens dispatch. The topography was divided into 36 10° slices and the maximal RCRP (mRCRP) in each was calculated and fitted into a model that integrated the effects of mean refractive power (M), corneal asymmetry (f1), and astigmatism (f2). The relationship between the probability of achieving effective control and the modulation of mRCRP was analyzed with logistic regression.ResultsA total of 45 subjects achieved effective control, but for 10 the treatment was ineffective. The M-values were not different between the groups. Modulations of mRCRP were significantly larger in the effective than the ineffective group (1.17 vs. 0.64 diopters [D] for f1, P = 0.02; 0.85 vs. 0.35 D for f2, P = 0.03). The probability to achieve effective control increased with modulation of mRCRP (P = 0.02). With a peak mRCRP > 4.5 D, a subject had an above 80% chance to achieve effective control.ConclusionsThe new method reveals that how the combination of spherical equivalent (SE), corneal asymmetry, and astigmatism determines modulation of the mRCRP and a large amplitude of modulation is associated with a higher probability of effective myopic control.Translational RelevanceOur finding enables clinicians to estimate the outcome early and provides new insights to lens design.

Background The aim of this study was to explore the differences in terms of tear film and meibomian glands (MGs) between young Asian soft contact lens (CL) wearers and non-wearers. Methods A prospective, cross-sectional observational study was conducted using 148 subjects (63 non-wearers, and 85 soft CL wearers who had been wearing CLs for more than 1 year) recruited from a clinic in Tianjin, China. All subjects first responded to an Ocular Surface Disease Index (OSDI) questionnaire and then underwent a standardized dry eye examination, which included measuring tear meniscus height (TMH), non-invasive tear breakup time (NIBUT), and corneal fluorescein staining (CFS). The MGs were evaluated via ImageJ, distorted MG count and the MG dropout were recorded. Results Compared to the control group (non-wearers), the CL group recorded higher OSDI and CFS scores, lower TMH and NITBUT values, a larger distorted MG count, and larger MG dropout (all P < 0.05). Pearson correlation analysis found a correlation between MG dropout and the duration of CL use (r = 0.440, P < 0.001), OSDI (r = 0.298, P = 0.006), and CFS scores (r = 0.442, P < 0.001). Conclusion CL wearers showed higher MG dropout and reduced TMH and NITBUT, which likely contributes to severe CL-related dry eye symptoms. CL use may lead to a higher MG dropout rate, and the extent of the MG dropout presumably influences the tear film status in CL wearers.

Objective: To investigate the lens decentration (LD) of orthokeratology (ortho-k) and the association between pretreatment corneal topographic parameters and LD of the ortho-k. Methods: Fifty right eyes of 50 myopes wearing ortho-k lenses were included in the prospective study. Corneal topography was conducted pretreatment to get topographic corneal parameters, including flat-K (K1); steep-K (K2); corneal astigmatism (CA), CA at 0 to 3 mm (3 mm-CA), 3 to 5 mm (5 mm-CA), 5 to 7 mm (7 mm-CA); surface asymmetry index (SAI); surface regularity index; the curvature of best-fit sphere; the diameter of cornea (DC); the distance from the corneal center to the corneal vertex (CCCV); flat eccentricity (E1), steep eccentricity (E2), and E1/E2 (E ratio); and the corneal curvature differences between the nasal and temporal quadrants at 0 to 3 mm (3 mm-Knt), and the corneal curvature differences between the superior and inferior quadrants at 0 to 3 mm (3 mm-Ksi), 5 mm-Knt (at 3–5 mm), 5 mm-Ksi (at 3–5 mm), 7 mm-Knt (at 5–7 mm), and 7 mm-Ksi (at 5–7 mm). The relationship between these cornea topographic parameters and LD of the ortho-k was tested using stepwise multiple linear regression models. Results: The mean magnitude of LD was 0.51±0.23 mm (0.06–1.03 mm). According to the stepwise analysis, 4 factors were associated with the overall LD (P<0.01): SAI (β=0.252), CCCV (β=0.539), 5 mm-CA (β=−0.268), and 3 mm-Ksi (β=−0.374); 5 factors were associated with the horizontal LD (P<0.01): DC (β=0.205), CCCV (β=0.881), 3 mm-CA (β=−0.217), 5 mm-Knt (β=0.15), and 3 mm-Ksi (β=−0.18); and 3 factors were associated with the vertical LD (P<0.01): SAI (β=0.542), 5 mm-CA (β=−0.188), and 3 mm-Ksi (β=−0.213). Conclusion: Lens decentration is most common, but in most cases, the amount of LD is moderate and acceptable. The magnitude of LD can be predetermined by topographic corneal parameters. Surface asymmetry index, CCCV, 5 mm-Knt, and 3 mm-Ksi may be more preferable parameters in terms of the assessment of LD of ortho-k.

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