A Comparison Between Refraction From an Adaptive Optics Visual Simulator and Clinical Refractions

Bibliometric analysis of hotspots and trends of global myopia research

AIM

To gain insights into the global research hotspots and trends of myopia.

METHODS

Articles were downloaded from January 1, 2013 to December 31, 2022 from the Science Core Database website and were mainly statistically analyzed by bibliometrics software.

RESULTS

A total of 444 institutions in 87 countries published 4124 articles. Between 2013 and 2022, China had the highest number of publications (n=1865) and the highest H-index (61). Sun Yat-sen University had the highest number of publications (n=229) and the highest H-index (33). Ophthalmology is the main category in related journals. Citations from 2020 to 2022 highlight keywords of options and reference, child health (pediatrics), myopic traction mechanism, public health, and machine learning, which represent research frontiers.

CONCLUSION

Myopia has become a hot research field. China and Chinese institutions have the strongest academic influence in the field from 2013 to 2022. The main driver of myopic research is still medical or ophthalmologists. This study highlights the importance of public health in addressing the global rise in myopia, especially its impact on children's health. At present, a unified theoretical system is still needed. Accurate surgical and therapeutic solutions must be proposed for people with different characteristics to manage and intervene refractive errors. In addition, the benefits of artificial intelligence (AI) models are also reflected in disease monitoring and prediction.

Multi-toric optical element to compensate ocular astigmatism with increased tolerance under rotation

A new, to the best of our knowledge, optical element designed to compensate regular astigmatism while exhibiting increased tolerance to rotational misalignment is introduced. The element incorporates an optical design based on concentric annular regions with slightly different cylindrical axis angular positions. To assess visual quality performance as a function of rotation, retinal image simulation and clinical assessments with an adaptive optics visual simulator were carried out. The results demonstrate the superior performance of the newly proposed element in the presence of rotational errors when compared to traditional solutions.

Age-related changes in geometry and transparency of human crystalline lens revealed by optical signal discontinuity zones in swept-source OCT images

BACKGROUND

The shape and microstructure of the human crystalline lens alter with ageing, and this has an effect on the optical properties of the eye. The aim of this study was to characterise the age-related differences in the morphology and transparency of the eye lenses of healthy subjects through the optical signal discontinuity (OSD) zones in optical coherence tomography (OCT) images. We also investigated the association of those changes with the optical quality of the eye and visual function.

METHODS

OCT images of the anterior segment of 49 eyes of subjects (9-78 years) were acquired, and the OSD zones (nucleus, C1-C4 cortical zones) were identified. Central thickness, curvature and optical density were measured. The eye's optical quality was evaluated by the objective scatter index (OSI). Contrast sensitivity and visual acuity tests were performed. The correlation between extracted parameters and age was assessed.

RESULTS

The increase in lens thickness with age was dominated by the thickening of the cortical zone C3 (0.0146 mm/year). The curvature radii of the anterior lens surface and both anterior and posterior nucleo-cortical interfaces decreased with age (- 0.053 mm/year, - 0.013 mm/year and - 0.006 mm/year, respectively), and no change was observed for the posterior lens radius. OCT-based densitometry revealed significant correlations with age for all zones except for C1β, and the highest increase in density was in the C2-C4 zones (R = 0.45, 0.74, 0.56, respectively, P < 0.001). Increase in OSI was associated with the degradation of visual function.

CONCLUSIONS

OCT enables the identification of OSD zones of the crystalline lens. The most significant age-related changes occur in the C3 zone as it thickens with age at a faster rate and becomes more opaque than other OSD zones. The changes are associated with optical quality deterioration and reduction of visual performance. These findings contribute to a better understanding of the structure-function relationship of the ageing lens and offer insights into both pathological and aging alterations.

Prospective evaluation of the ESCRS online calculator for calculation of a multifocal intraocular lens

PURPOSE

To evaluate a recently introduced ESCRS online calculator for intraocular lens (IOL) calculation of a multifocal IOL in refractive lens exchange and cataract surgery in a prospective setting.

SETTING

Department of Ophthalmology, Goethe University Frankfurt, Germany.

DESIGN

Prospective, consecutive case series.

METHODS

Eyes that received lens extraction and multifocal IOL implantation were included. The mean prediction error, mean absolute error, and median absolute prediction error (MedAE) provided by the ESCRS online calculator were compared, as were the number of eyes within ±0.5 diopters (D), ±1.0 D, ±2.0 D of target refraction. The SRK/T formula was also included for comparison. Postoperative spherical equivalent was measured at 3 months. 1 eye per patient was included.

RESULTS

88 eyes from 88 patients with a mean age of 62 ± 9.5 years were included. The MedAE was low for all formulas and ranged from 0.26 D (Kane), Hill-RBF (0.27 D), Hoffer Q Savini/Taroni (Hoffer QST) (0.27 D), Barrett Universal II (BUII) (0.28 D), Emmetropia Verifying Optical (EVO) (0.29 D), Cooke K6 (0.27 D), 0.30 D (Postoperative spherical Equivalent prediction using Artificial intelligence and Linear algorithms, by Debellemaniére, Gatinel, and Saad [Pearl DGS]) to 0.31 D (SRK/T). No statistically significant difference was found ( P = .627). Considering the number of eyes within ±0.5 D of the calculated refraction the best performing was again the Hill-RBF (84%, 74 eyes), again followed by Kane (71, 81%), EVO, Pearl DGS, Hoffer QST, BUII (each 80%, 70 eyes), Cooke K6 (78%, 69 eyes), and SRK/T (74%). Again, no statistically significant difference was found ( P = .39).

CONCLUSIONS

Using a recently introduced ESCRS online IOL calculator in multifocal IOLs leds to a high number of eyes reaching target refraction and low prediction errors. All formulas performed similarly well. Hill-RBF showed the highest number of eyes within ±0.5 D, but no significance was found.

Myopia Progression in Adults: A Retrospective Analysis

SIGNIFICANCE

Studies on adult myopia progression are limited. This retrospective analysis of a large data set of young adult myopes characterizes myopia progression during adulthood.

PURPOSE

This study aimed to determine the mean annual progression of myopia and to estimate the proportion of progressors in adult myopes.

METHODS

Longitudinal, noncycloplegic subjective refraction data for young adult myopes (spherical equivalent refractive error, -0.5 D or more), age ranging from 18 to 30 years, were retrospectively analyzed. The mean annual progression, as well as the proportion of progressors (at least -0.50 D shift between visits and annualized progression of -0.25 D or more), was estimated.

RESULTS

A total of 354 myopes (230 females [64.7%]), with a mean (standard deviation) age of 22.2 (3.8) years, were considered. The mean (standard deviation) annualized progression was -0.10 (0.21), -0.08 (0.2), and -0.04 (0.21) D in the 18- to 21-year, 22- to 26-year, and 27- to 30-year age groups, respectively ( P = .003). The difference between 18- to 21- and 27- to 30-year age groups was significant ( P = .05), whereas all other pairwise comparisons were not significant. The proportion (95% confidence interval) of progressors in the 18- to 21-, >21- to 26-, and >26- to 30-year age groups was 18.3% (14.9 to 21.7%), 10.9% (7.1 to 14.7%), and 8.8% (4.4 to 13.1%), respectively. The proportion of progressors working or studying in a higher learning/academic environment was 16.2% with an odds ratio (95% confidence interval) for progression of 2.07 (1.15 to 3.74) compared with those in nonacademic environments ( P = .02), with no significant effect of sex or ethnicity.

CONCLUSIONS

This study is consistent with other studies on myopia in young adults, which show that myopia does not progress by substantial amounts throughout the adult years, particularly after the age of 21 years. Although future studies may be challenged by the small rates of change and the small proportion of progressors, further research is needed to understand the implications of adult myopia progression on clinical management.

Optical Performance of a Segmented Extended-Depth-of-Focus Intraocular Lens under the Influence of Different Values of Spherical Aberration Generated by Refractive Surgery

BACKGROUND

Corneal refractive surgery induces high-order aberrations, specifically spherical aberration (SA). These aberrations can have implications when patients later develop cataracts and require the implantation of multifocal intraocular lenses (MIOLs). MIOLs with asymmetric designs pose challenges in predicting outcomes, particularly in these cases. The aim of this study was to evaluate how different values of SA, resulting from various types of refractive surgeries, affect the optical performance of the FEMTIS Comfort intraocular lens.

METHODS

The through-focus modulation transfer function (TF-MTF) curve and high-contrast images of tumbling E were used as parameters to assess the optical performance of the MIOL. These parameters were measured using an adaptive optics visual simulator.

RESULTS

Increasingly negative values of SA make the MIOL more bifocal, moderating its extended-depth-of-focus characteristic. Conversely, higher positive SA values cause the TF-MTF curve to shift towards positive vergences, leading to worsened distance vision in the +1.00 to +2.00 D range, but improved vision in the +0.50 D to +1.00 D range.

CONCLUSIONS

Assessing SA in patients prior to implanting MIOLs with asymmetric designs is necessary for predicting outcomes and making informed decisions based on the visual requirements of patients.

Functional visual tests to evaluate the effect of small astigmatism correction with toric contact lenses

The prescription of daily contact lenses does not often include a full astigmatic correction. We question here whether this full astigmatic correction (for low to moderate astigmatism) provides a substantial improvement in the overall visual performance compared to a more conservative approach based only on the prescription of spherical contact lenses. The visual performance of 56 contact lens neophytes divided in two contact lens fitting groups (toric versus spherical lens fit) was assessed using standard visual acuity and contrast sensitivity tests. A new set of functional tests simulating everyday tasks was also used. Results showed that subjects with toric lenses had significantly better visual acuity and contrast sensitivity than those with spherical lenses. Functional tests did not render significant differences between groups, which was explained by several factors like i) the visual demand of the functional tests, ii) the dynamic blur due to misalignments and iii) small misfits between the available and measured axis of the astigmatic contact lens.

Comparisons of objective and subjective refraction with and without cycloplegia using binocular wavefront optometer with autorefraction and retinoscopy in school-age children

Purpose

To compare school-age children’s objective and subjective refraction using a binocular wavefront optometer (BWFOM) with autorefraction and retinoscopy before and after cycloplegia.

Methods

Eighty-six eyes from 86 children (6–15 years old) were enrolled in this cross-sectional study. BWFOM objective and subjective refractions were compared with autorefraction and retinoscopy under cycloplegia. BWFOM refraction was evaluated before and after cycloplegia. Measurements were compared using a paired t-test; agreement was assessed using Bland–Altman plots.

Results

Under cycloplegia, the sphere, spherical equivalence, and J45 were significantly more negative on BWFOM objective refraction than autorefraction (− 1.39 ± 2.20 D vs. − 1.28 ± 2.23 D, P = 0.003; − 1.84 ± 2.38 D vs. − 1.72 ± 2.43 D, P = 0.001; − 0.02 ± 0.17 D vs. 0.03 ± 0.21 D, P = 0.004). The subjective sphere of BWFOM was less myopic, and the cylinder and the J45 were more negative than those with retinoscopy (− 1.17 ± 2.09 D vs. − 1.25 ± 2.20 D, P = 0.02; − 0.91 ± 0.92 D vs. − 0.76 ± 0.92 D, P < 0.001; − 0.01 ± 0.15 D vs. 0.03 ± 0.21 D, P = 0.028). For both BWFOM objective and subjective refraction, sphere and spherical equivalence with noncycloplegia were more myopic than those with cycloplegia (objective: − 1.76 ± 2.10 D vs. − 1.39 ± 2.20 D, − 2.21 ± 2.30 D vs. − 1.84 ± 2.38 D, P < 0.001; subjective: − 1.57 ± 1.92 D vs. − 1.17 ± 2.09 D, − 2.01 ± 2.13 D vs. − 1.62 ± 2.27 D, P < 0.001). Bland–Altman plots showed good agreement in spherical equivalence between BWFOM objective refraction and autorefraction (mean difference = 0.12 D, 95% confidence interval [CI] − 0.52 to 0.76), subjective refraction with retinoscopy (mean difference =  − 0.01 D, 95% CI − 0.65 to 0.64), and BWFOM refractions with or without cycloplegia (objective: mean difference =  − 0.37 D, 95% CI − 1.31 to 0.57; subjective: mean difference =  − 0.39 D, 95% CI − 1.30 to 0.51). The time cost by BWFOM was significantly less than the total time of autorefraction and retinoscopy (264.88 ± 90.67 s vs. 315.89 ± 95.31 s, P < 0.001).

Conclusion

BWFOM is a new device that realizes both objective and subjective refraction. For children’s refractive errors, it is more convenient and quicker to obtain the proper prescription at a 0.05-D interval, and it is more accurate than autorefraction and retinoscopy under cycloplegia.