Investigation of retinal microvasculature and choriocapillaris in adolescent myopic patients with astigmatism undergoing orthokeratology

Dynamic changes of choroidal vasculature and its association with myopia control efficacy in children during 1-year orthokeratology treatment

PURPOSE

To investigate the dynamic changes of choroidal vasculature and its association in mediating ocular elongation over 1 year of orthokeratology (ortho-k) treatment.

METHODS

This observational study included 8-14 year old myopic children who were willing to receive ortho-k treatment or wear single vision spectacle lenses (SVL). Axial length (AL) and choroidal characteristics, including submacular luminal area (LA), stromal area (SA), total choroidal area (TCA), choroidal vascularity index (CVI), subfoveal choroidal thickness (SFCT) and choriocapillaris flow deficits (CcFD) from OCT/OCTA images, were evaluated at baseline, 3, 6 and 12 months.

RESULTS

After 1 year, AL elongation was significantly less in 25 children treated with ortho-k than in 29 children wearing SVL (0.17 ± 0.14 v.s. 0.28 ± 0.16 mm, P<0.01). In the ortho-k group, LA, SA, TCA and SFCT were significantly increased by 0.033 ± 0.059 mm2, 0.024 ± 0.035 mm2, 0.058 ± 0.087 mm2, 8.9 ± 17.4 μm, respectively, at 3 months (all P<0.05). These parameters returned to near baseline levels over the following 9 months. Meanwhile, CcFD decreased by 0.83 ± 1.09 % over 12 months, but CVI remained steady during this period. No significant changes in these choroidal parameters (except for CcFD, decreased by -0.56 ± 1.23 %) were observed in the SVL group over 12 months. Increases in SFCT, LA, SA and TCA over 12 months were significantly greater in the ortho-k group than in the SVL group. Mediation analyses showed that 44.8 % of effect on inhibiting AL elongation through ortho-k was mediated via TCA (in particular LA).

CONCLUSIONS

The decelerated ocular elongation during ortho-k treatment is accompanied by increases in content of choroidal vascular lumen and stromal component. Dynamic changes of choroidal vasculature provide a possible mechanism underlying myopia control efficacy via ortho-k.

Impact of back optic zone diameter (BOZD) in orthokeratology on axial length elongation: A meta-analysis and systematic review

PURPOSE

Myopia has emerged as a significant public health concern. Recent studies have demonstrated that Orthokeratology (Ortho-K) can effectively decelerate axial length (AL) growth, with eyes possessing smaller back optical zone diameters (BOZD) exhibiting greater effectiveness compared to those with larger BOZD. This study aims to analyze the impact of Ortho-K with varying BOZD.

METHOD

This systematic review involved the retrieval of articles from eight databases: PubMed, Embase, Web of Science, Cochrane, CNKI, Wanfang, Sinomed, and VIP, covering the period from each database's inception to January 2024. It compared axial length (AL) changes between smaller and larger back optic zone diameters (BOZD). Review Manager 5.4 was used to statistical analysis and the results presented as weighted mean differences and 95% confidence intervals (CI). This review adheres to the PRISMA guidelines.

RESULT

This systematic review included two randomized controlled trials (RCTs) and five cohort studies (CS), analyzing a total of 702 eyes (352 eyes are treated with Ortho-K and BOZD ≤ 5.5 mm, 350 eyes are treated with Ortho-K and BOZD ≥ 6.0 mm). The findings indicate that the Ortho-K with smaller BOZD significantly reduces AL growth [WMD = -0.13, 95 %CI (-0.16 to -0.10), P < 0.001].

CONCLUSION

The Ortho-K with smaller BOZD prove more effective in controlling myopic AL growth compared with larger BOZD. However, in clinical practice, it is necessary to comprehensively evaluating factors such as patient age, myopia diopter, pupil diameter, higher-order aberration, treatment zone area, and corneal eccentricity to achieve optimized outcomes in improving naked-eye vision and myopia controlling.

Changes in Subfoveal Choroidal Thickness after Orthokeratology in Myopic Children: A Systematic Review and Meta-Analysis

AIMS

This study aimed to synthesize the variations in subfoveal choroidal thickness (SFCT) observed at different follow-up intervals in myopic children undergoing orthokeratology treatment.

MATERIALS AND METHODS

Relevant articles were systematically retrieved from databases such as PubMed, EMBASE, Web of Science, and Cochrane Library. The retrieval period extended from the inception of these databases to November 2023. Means and standard deviations (SD) of baseline and post-treatment SFCT were selected as the results for analysis and calculation.

RESULTS

A total of eight articles involving 478 eyes fulfilled the inclusion criteria. At 1 month, 3 months, and 6 months intervals, the SFCT demonstrated significant increases by 16.74 μm (95% CI: 8.66, 24.82; p < 0.0001), 13.41 μm (95% CI: 4.36, 22.45; p = 0.004), and 17.57 μm (95% CI: 8.41, 26.73; p = 0.0002), respectively. Besides, children treated with orthokeratology exhibited a notably thicker change of SFCT in comparison with children with single-vision spectacles (SVL) (WMD = 13.50, 95% CI: 11.69, 15.13; p < 0.0001).

CONCLUSION

Myopic children undergoing orthokeratology treatment experience a discernible increase in SFCT at 1 month, 3 months, and 6 months. Furthermore, compared to children utilizing SVL, those undergoing orthokeratology manifest a more pronounced thickening of SFCT.

Influencing factors associated with high myopia in Chinese college students

Background

High myopia (HM) may elicit irreversible pathological changes in the fundus and severely impair visual quality, thereby becoming a major public health issue in China. However, the influencing factors associated with HM remain unknown in Chinese college students, whose visual quality is crucial to country development.

Methods

This is a cross-sectional observational study. Two thousand three hundred and fifteen undergraduate and graduate students were initially recruited from various majors in 3 universities in Tianjin, China. Under the principle of voluntary participation and informed consent, simple random sampling was conducted in the recruited subjects while maintaining balanced number of subjects from each major. After screening with inclusion and exclusion criteria, 96 undergraduate and graduate students (186 eyes) were finally included and divided into non-HM and HM groups. The eyes of subjects were examined by optical coherence tomography angiography (OCTA) for vessel density and structure thickness at the macula and optic disc, and the subjects were surveyed by an itemized questionnaire on lifestyles and study habits.

Results

The OCTA and questionnaire results revealed 10 factors, including hemodynamic and anatomic parameters and lifestyle metrics, with statistical significance between the non-HM and HM groups. Receiver operating characteristic curve analysis showed that vessel density of the inner retina at the macula, vessel density of the radial peripapillary capillary at the optic disc, smartphone usage time, continuous near work time, and sleeping after midnight had superior values of area under the curve (AUC > 0.700). Therefore, these 5 factors were selected for univariant and multivariant logistic regression analyses. A prediction model comprising the 5 influencing factors had an AUC of 0.940 and 95% CI of 0.908-0.972.

Conclusion

This study for the first time identified the vessel density of the inner retina at the macula, the vessel density of the radial peripapillary capillary at the optic disc, smartphone usage time, continuous near work time, and sleeping after midnight as influencing factors associated with HM in Chinese college students. A prediction model comprising the 5 influencing factors was proposed for calculating likelihood of a Chinese college student developing HM, based on which lifestyle improvement and medical intervention might be recommended.