Increased Corneal Toricity after Long-Term Orthokeratology Lens Wear

The alterations in ocular biometric parameters following short-term discontinuation of long-term orthokeratology and prior to subsequent lens fitting: a preliminary study

PURPOSE

To investigate the alterations in biometric parameters among Chinese adolescents over an extended period of wearing orthokeratology lenses, as well as the subsequent changes after a one-month cessation of lens usage prior to the secondary lens fitting.

METHODS

Twenty-four myopic patients aged 7-14 were enrolled in this 37-month prospective observational study. Ocular biometric parameters were measured in the study. Ocular biometric parameters were assessed, and the utilization of Generalized Estimating Equations (GEE) was employed in the analysis to address the correlation between the two eyes of each participant.

RESULTS

The axial length (AL) increased by 0.55 mm after 36 months of lens wearing and further increased to 0.62 mm at the 37-month follow-up compared to the initial measurement. The differences in AL elongation per month between the 37-month time point and the 12-, 24-, and 36-month marks of lens wearing were found to be statistically significant (p12-month = 0.001; p24-month = 0.003; p36-month = 0.001). Following the cessation of lens wear for 1 month, there was no significant complete recovery observed in the flat and steep keratometry values. However, the intraocular pressure and anterior chamber depth returned to their baseline levels.

CONCLUSIONS

The AL elongation undergoes alterations during temporary discontinuation of lenses, with the flat and steep keratometry measurements remaining significantly flatter compared to the baseline. However, the intraocular pressure and anterior chamber depth return to their initial levels after one month of lens cessation.

Trends in myopia management attitudes and strategies in clinical practice: Survey of eye care practitioners in Africa

PURPOSE

There remains a lack of information on the perception and adoption of myopia control strategies among African eye care practitioners (ECPs). This study provides an African perspective to similar previous studies conducted in other parts of the world.

METHODS

A self-administered survey in English and French was distributed to ECPs across Africa. The items on the questionnaire assessed their level of concern about the increasing prevalence of paediatric myopia, perceived efficacy, opinions on, and adoption of various myopia management modalities.

RESULTS

Responses were obtained from 330 ECPs working in 23 African countries. Respondents were highly concerned about the increasing prevalence of paediatric myopia in their clinic (median 8/10) and perceived approved myopia control soft contact lenses as the most effective at slowing myopia progression (mean perceived reduction in myopia progression ± SD; 53.9 ± 27.1%), followed by single vision spectacles (53.1 ± 30.9%), and orthokeratology (52.8 ± 28.0%). Multifocal soft contact lenses (40.4 ± 25.8%) and pharmaceutical agents such as topical atropine drops (39.5 ± 27.1%) were perceived as least effective in slowing myopia progression. Although ECPs reported being aware of various myopia control strategies, they still mainly prescribed single vision spectacles to a large proportion (64.3 ± 29.9%) of young progressing myopes. Nearly one-third (27%) of ECPs who prescribed single vision lenses stated they were concerned about the cost implications to patients. Other reported concerns included safety of, and inadequate information about myopia control options.

CONCLUSIONS

African ECPs continue to prescribe single vision lenses for progressing myopes despite being aware of the various myopia control options. Practitioners' perceptions of the efficacy of several modalities to slow myopia progression do not align with the current best evidence. Clear practice guidelines and continuing education on myopia control are warranted to inform and guide the management of myopic patients in Africa.

Thickness profiles of the corneal epithelium along the steep and flat meridians of astigmatic corneas after orthokeratology

Background

The aim of this study was to investigate the changes in corneal epithelial thickness along the principle meridians of astigmatic corneas after six months of overnight spherical myopic orthokeratology (OK) lens wear.

Methods

This is a prospective study. Fifty-seven subjects with up to 1.50 diopters (D) of corneal toricity wore spherical OK lenses for 6 months. Evaluations of OK lens fit, visual acuity, refractions and corneal toricity (CT) were performed. Fourier-domain optical coherence tomography (FD-OCT) was conducted to measure the corneal epithelial thickness (ET) along the principle meridians of corneal toricity over a diameter of 6 mm. The means of △ET of the same diameter at individual meridians (△ETSm and △ETFm) were calculated and compared.

Results

Visual acuity and refraction improved significantly after OK lens wear. △ETFm thinned more than △ETSm (P = 0.027) at 1.5 mm in radius. △ETSm thickened more than △ETFm at 2.5 mm (P = 0.019) and 3.0 mm (P = 0.036).∣△ETSm - △ETFm∣ were significantly correlated with the baseline central CT at 2.0 mm, 2.5 mm and 3.0 mm. ∣△ETSm - △ETFm∣was significantly correlated with the baseline peripheral CT at 2.5 mm.

Conclusions

Overnight wear of spherical OK lenses resulted in differential changes in the thickness profiles of the corneal epithelium between the steep and flat meridians in eyes with corneal toricity.