Ophthalmic and Physiological Optics最新文献

Purpose: Defocus Incorporated Soft Contact (DISC) lenses with +2.50 D myopic defocus reduced myopia progression by 25% in a previous randomised clinical trial (RCT). The current study aimed to evaluate if a stronger myopic defocus, +3.50 D with variable myopic defocus (DISC3.5plus), could slow myopia progression compared with single vision (SV) soft contact lenses in a 12-month RCT.

Methods: Conducted from December 2018 to January 2021, the current RCT randomly assigned myopic children to wear DISC3.5plus (n = 87) or SV (n = 80) lenses. Myopia progression and axial elongation were compared between the two groups. Analyses were performed for both enrolled and completed participants.

Results: For all enrolled participants, the DISC3.5plus group had significantly less myopia progression (mean difference: -0.15 ± 0.07 D, p = 0.02) and axial elongation (mean difference: 0.04 ± 0.02 D, p = 0.04) than the SV group at 6 months but not at 12 months (myopia progression: p = 0.11; axial elongation: p = 0.13). For completed participants, the DISC3.5plus group (n = 33) had reduced myopia progression at both 6 months (0.25 ± 0.07 D, p = 0.001) and 12 months (0.19 ± 0.09 D, p = 0.049) compared with the SV group (n = 40), but not in axial elongation (6 months: p = 0.16; 12 months: p = 0.32). In January 2020, the coronavirus pandemic disturbed contact lens-wearing patterns.

Conclusion: DISC3.5plus lenses significantly slowed myopia progression and axial elongation compared with SV lenses for all enrolled participants over 6 months. The pandemic hindered longer term efficacy follow-up and sample size; thus, further investigation with more participants is needed to confirm sustained treatment effects.

Purpose: To determine whether imaging features derived from fundus photographs contain 3D eye shape information beyond that available from spherical equivalent refraction (SER).

Methods: We analysed 99 eyes of 68 normal adults in the UK Biobank. An ellipsoid was fitted to the entire volume of each posterior eye (vitreous chamber without the lens)-segmented from magnetic resonance imaging of the brain. Asphericity was computed based on the semidiameters of the ellipsoid's axes to describe posterior eye shape along the horizontal (temporal-nasal) and vertical (superior-inferior) meridians, while volume was calculated as the total number of foreground voxels. Mixed-effects linear regression models were used to test the association of SER with asphericity and volume, controlling for age and sex. Then, the association between various fundus features and asphericity was tested-both before and after controlling for SER, age and sex.

Results: Posterior eyes were generally oblate (asphericity > 0), but the degree of oblateness reduced as SER decreased, with the shape tending towards prolateness in high myopia. Neither sex nor age influenced asphericity. However, males had larger posterior eyes on average (this difference disappeared after height was additionally controlled for). Optic disc (OD) orientation, OD-fovea angle, vessel tortuosity, vessel fractal dimension and central retinal arteriolar or venular equivalent (CRAE or CRVE) showed significant univariable associations with asphericity along at least one meridian. After controlling for SER, age and sex, a more negative OD-fovea angle (larger OD-fovea angular separation) remained significantly associated with reduced horizontal oblateness (p = 0.01). Similarly, decreasing CRAE (narrower arterioles) remained significantly associated with reduced oblateness along both the horizontal (p = 0.04) and vertical (p < 0.01) meridians.

Conclusions: Variations in OD-fovea angle and CRAE are associated with differences in ocular asphericity-even in eyes with similar SER-suggesting that fundus imaging provides eye shape information beyond what is available from refractive error alone.

In this paper, three key questions regarding our understanding of myopia are addressed: predictors of myopia onset, the mechanism underlying its development and potential treatments to slow its progression. To explore these aspects, first, a non-invasive biomarker using the chicken model of myopia was investigated. A strong correlation was found between myopia development and both increased ultraviolet (UV) fundus reflectivity and thinning of the retinal nerve fibre layer (RNFL). Through electron microscopy, it was observed that, within hours of vision deprivation, significant thinning of the myelin sheaths around large axons in the RNFL occurred, accompanied by an increase in UV fundus reflectivity-changes that took place even before eye elongation. These findings suggest that early myelin degradation contributes to myopia development and may serve as a predictive biomarker in the animal model. However, the prediction of myopia onset in humans remains challenging. To investigate the mechanism of myopia development further, visual stimuli affecting emmetropic and myopic eyes differently were examined. The results indicated that myopic eyes have weaker responses to positive defocus and short-term stimulation to simulated chromatic aberrations when compared with emmetropic eyes, suggesting a possible impairment in retinal signalling pathways responsible for detecting blur and defocus. In terms of treatment, it was found that reading large text with inverted contrast (bright letters on a dark background) induced axial length shortening and choroidal thickening in both emmetropic and myopic eyes. Furthermore, repeated exposure to digitally simulated myopic chromatic defocus was shown to reduce axial length and increase choroidal thickness effectively in myopic human subjects. These findings align with results from animal models and indicate that this approach may serve as a potential strategy for myopia control. However, more research is necessary to establish an effective myopia control intervention suitable for children and adolescents.

Purpose: This study evaluated visual parameters and cortical activity after wearing myopia control spectacle lenses with defocus incorporated multiple segments (DIMS).

Methods: Myopic adults between 20 and 30 years of age were enrolled. The study consisted of (1) examination of visual parameters and (2) measurement of cortical responses, while wearing single vision lenses (SVL) and MiYOSMART (MS) lenses in counterbalanced order after a two-week adaptation period. Visual parameters tested were: high-contrast visual acuity (HCVA) and low-contrast visual acuity (LCVA), contrast sensitivity, heterophoria, near point of convergence (NPC), stereopsis, accommodative facility and the accommodative response. Cortical responses were assessed by visual evoked potentials (VEPs), recorded from 10 electrodes placed over the parieto-occipital area.

Results: MiYOSMART lenses produced slightly better HCVA than SVL (-0.25 vs. -0.21 logMAR, p = 0.02) and a larger accommodative response (MS 1.68 D; SVL 1.53 D, p < 0.001). No significant differences in LCVA, heterophoria, NPC, stereopsis or contrast sensitivity were observed. The latencies and amplitudes of the early and late components of the VEPs (C1, N1, P1, P2) did not differ significantly between lenses.

Conclusions: This study found no clinically significant differences in visual parameters or visual cortex responses between SVL and MS lenses after 2 weeks of adaptation. These results confirm the absence of adverse visual effects from DIMS lenses for myopia control.

Purpose: The purpose of this study was to determine the relationship between macular sensitivity (MS) and posterior staphyloma (PS) in highly myopic eyes.

Methods: This cross-sectional, observational study included 646 highly myopic eyes (spherical equivalent (SE) ≤-5.00D and the international meta-analysis for pathologic myopia classification grade of <2) from 362 participants. MS was measured using microperimetry and evaluated between eyes with and without PS. Correlations between MS and PS were determined in multivariate regression models.

Results: Although there was no significant difference in best-corrected visual acuity (BCVA) (p = 0.07), the MS of the PS group was significantly lower than the no PS group at the central 2°, 4°, 6°, 8° and 10° (all p < 0.001). After controlling age, axial length (AL) and SE, the MS in the PS group was still lower than the no PS group from 2° to 10° (all p < 0.05). In a multivariable analysis adjusting for age, AL, SE and BCVA, the presence of PS was significantly associated with lower MS in the central 2°-10° (all p < 0.05).

Conclusions: Lower MS was independently associated with the presence of PS in highly myopic eyes. Even when BCVA was not significantly different, MS still could reveal subtle changes in visual function in highly myopic eyes with PS.