Binocular vision parameters and visual performance in bilateral keratoconus corrected with spectacles versus rigid gas-permeable contact lenses / Parámetros de visión binocular y rendimiento visual en queratocono bilateral corregido con gafas versus lentes de contacto rígidos permeables al gas

Purpose: To analyze binocular vision of individuals aged 18 to 35 years diagnosed with keratoconus, utilizing spectacles and rigid gas-permeable (RGP) contact lenses. Research was led by the Universidad Autónoma de Aguascalientes, México and Fundación Universitaria del Área Andina Pereira, Colombia. Methods: A single center, prospective non-randomized, comparative, interventional, open-label study, in which the differences in binocular vision performance with both spectacles and RGP contact lenses was carried out from December 2018 to December 2019. Sampling was performed according to consecutive cases with keratoconus that met the inclusion criteria until the proposed sample size was reached. Results: Rigid gas-permeable (RGP) contact lenses notably enhanced distance and near visual acuity in keratoconus patients compared to spectacles. Visual alignment analysis shows exophoria at both distances and is slightly higher with RGP contact lenses. The difference was statistically significant (p<0.05), with 82.5 % presenting compensated phoria with spectacles and pnly 42.50% with RGP contact lenses. Stereoscopic vision improved while wearing RGP contact lenses (42.59 %), although accommodation and accommodative flexibility remained within normal ranges. Conclusions: Patients with keratoconus fitted with RGP contact lenses have improved binocular vision skills such as visual acuity, stereopsis, and accommodative flexibility. However, even when the vergence and motor system is decompensated with respect to normal ranges, the range between break and recovery points for both fusional reserves and the near point of convergence (NPC) improves with the use of RGP contact lenses, giving indications of an adaptive condition of the motor system from the medium to the long term.(AU)

[Overview of intraocular lenses with optics for correcting presbyopia]. / Übersicht über Intraokularlinsen mit Presbyopie-korrigierenden Optiken.

BACKGROUND: In recent years intraocular lenses (IOLs) for correcting presbyopia have been significantly improved and diversified. There are currently many different IOL models based on a wide variety of optical designs. OBJECTIVE: The wide variety of available IOL solutions to correct presbyopia can be challenging for surgeons and patients. In everyday practice, the question is which IOL is best for which patient. MATERIAL AND METHODS: This overview describes and categorizes the currently available implants. The respective optical properties are analyzed and clinical study results are discussed, in particular those evaluating visual performance and the occurrence of photic phenomena. RESULTS: Monofocal-plus IOLs provide improved intermediate visual acuity with optimal distant visual acuity and minimal photic phenomena. Extended depth of field (EDoF) IOLs extend the depth of field through different optical principles and provide good distant and intermediate visual acuity. Trifocal lenses enable the greatest independence from spectacles at the price of a higher probability of dysphotopsia. CONCLUSION: The selection of the most suitable IOL for correction of presbyopia requires a balance between the patient's visual needs and possible side effects. An adequate knowledge of the currently available implants allows a patient-oriented selection of IOLs.

Effect of Light Sources on Transmittance of Commercially Available Contact Lenses.

BACKGROUND: Previous studies have suggested that light rays may interact with contact lenses, potentially affecting their transmittance. AIM: This study aimed to investigate the effects of visible and ultraviolet (UV)-A light sources on the transmittance of some commercially available daily, weekly, and monthly contact lenses. METHODS: Nine commercially available soft contact lenses were irradiated with a solar simulator, light-emitting diode (LED) source, laser source, and UV-A source. The average transmittance of the tested lenses before and after irradiation in the UV, visible, and infrared light wavelength ranges was determined using an Agilent UV-visible spectrophotometer, model 8453. RESULTS: The results showed a partial or complete block of UV transmission at the UV-B region (300 nm) and the UV-A region (355 nm) by the Bio true daily contact lens, as well as the Acuvue Oasys, Avaira, and Biomedics 55 weekly lenses. At the visible region (555 nm), irradiation of the contact lenses by different light sources resulted in reduced light transmittance. At the infrared region (900 nm), the weekly and monthly contact lenses partially blocked infrared transmission, while the daily lenses showed either increased or decreased infrared transmission. CONCLUSIONS: Solar and artificial lighting, as well as high-powered lasers, constitute a major concern on the contact lenses' light transmission and optical properties. It is essential to develop soft contact lenses that have photoprotective properties while maintaining visible light transmittance.

[Optical benchtop evaluation of special intraocular lens optics]. / Optische Bank-Evaluierung für spezielle Intraokularlinsenoptiken.

Intraocular lenses (IOL) featuring complex optical designs can pose a challenge in understanding their performance, which may hinder making an informed decision when selecting suitable lenses for patients. This underlines the importance of collecting optical quality data of IOLs and making them available. The deployment of benchtop systems for IOL testing offers not only insights into the design features of various IOL solutions but also provides a platform for objective comparisons of special optics designs, including information about their susceptibility to photic phenomena. Recent advances in IOL testing have improved the ability to predict functional effects on visual acuity and contrast sensitivity from objective optical quality metrics. This, for instance, can be used to study monofocal lenses and the impact of asphericity on vision and IOLs tolerance to misalignment. Monofocal-plus IOLs consistently show only a slight improvement in the depth of focus when tested on the optical bench and in clinical settings. Although the pupil dependence found in this technology may limit the advantages of monofocal-plus over standard monofocal technology to extend the range of vision, it is the key to reduce photic phenomena. Refractive and diffractive extended depth of focus (EDOF) IOLs can effectively enhance intermediate vision, with the latter offering a slightly broader depth of focus but potentially increasing the risk of dysphotopsia. However, the limitation of EDOF IOLs is that they often fail to deliver spectacle independence for reading, which can be overcome by trifocal technology. Still, the available trifocal IOLs differ in their location of intermediate and near foci and the susceptibility to produce glare effects. Therefore, the knowledge from optical benchtop testing of IOLs can support optimizing the IOL selection by aligning the patient's visual needs with the IOL's properties, setting the right expectations, and assessing the risk profile for the occurrence of photic phenomena, potentially leading to improved decision-making.

Analyzing the effect of blue-blocking lenses on color vision tests using the chromaticity coordinate method.

Significance: Blue light with wavelengths of 380-445 nm can harm the retina, leading to the development of blue-blocking lenses (BBLs). Understanding whether BBLs affect color vision test outcomes and color discrimination ability is crucial for people in color-associated jobs. Aim: This study aimed to evaluate the effect of BBLs on color vision tests and analyze color discrimination using mathematical models of color spaces. Approach: Six pseudoisochromatic (PIC) tests and two Farnsworth-Munsell (FM) tests were conducted to assess participants' color vision. Friedman signed rank test was used to compare the outcomes of the Farnsworth-Munsell 100-Hue Tests (FM 100-Hue Tests) between the BBLs and ordinary lenses groups. The CIE color difference formula and a spectral illuminometer were employed to evaluate the color differences with and without BBLs. Results: All subjects showed normal outcomes in all PIC tests and Farnsworth-Munsell Dichotomous D-15 Tests (FM D-15 Tests). There were no significant differences between ordinary lenses group and BBLs groups in FM 100-Hue Tests. In the color space, the effect of BBLs on each color light was equivalent to a translation on the CIE 1931 chromaticity diagram with minor distortion. Since BBLs do not disrupt the continuity of the chromaticity diagram, or cause different colors to appear the same, they do not lead to color confusion. However, colors with short wavelengths exhibited more changes in color difference when wearing BBLs. Conclusions: BBLs do not impair the wearer's ability to discriminate colors or perform color vision tests accurately. However, BBLs can cause color differences especially in the recognition of blue hues.

Quality of life and vision assessment with scleral lenses in keratoconus.

PURPOSE: The purpose of the study is to evaluate the visual outcomes and improvement in quality of life (QOL) of patients with keratoconus with scleral lenses. METHODS: In this prospective study, 14 patients (28 eyes) with bilateral keratoconus were fitted with scleral lenses (McAsfeer 16.00 mm) in Pune city, Maharashtra, India. Uncorrected visual acuity (VA), best spectacle-corrected VA, and VA with scleral lenses were evaluated. The patients were given the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) for judging the QOL, before and after using scleral lenses for 3 months. RESULTS: The mean uncorrected VA of the 14 patients with a mean age of 28.64 ± 6.57 years was 1.18 ± 0.19 logMAR. Best spectacle-corrected high-contrast VA improved from 0.47 ± 0.25 logMAR to 0.03 ± 0.07 logMAR with scleral lenses (P < 0.001). Best spectacle-corrected low-contrast VA improved from 0.68 ± 0.22 logMAR to 00.47 ± 0.10 logMAR with scleral lenses (P < 0.001). Along with the increase in overall median scores on the NEI VFQ-25 from 1735 to 2930 points (P < 0.001), the distance and near activities (P < 0.001), vision-specific mental health (P < 0.002), social functioning (P < 0.004), and driving (P < 0.005) improved after using scleral lenses for 3 months. CONCLUSION: Scleral lenses can be an effective and safe management option for patients with keratoconus leading to an improved vision and QOL.

Visual rehabilitation with mini scleral contact lenses in scarred corneas.

PURPOSE: To present a case series of patients with corneal scars who were successfully fitted with mini scleral contact lenses (mSCL). METHODS: Case series study. RESULTS: Six eyes of six patients with corneal scars were fitted with mSCLs. All scars were situated in the visual axis within the scotopic pupillary zone. The sizes of the scars varied, with the smallest being confined to a central corneal area (case 5) and the largest covering the entire visual axis (case 2). In addition to compromising corneal transparency, these scars also induced significant corneal irregularities, especially in cases 1, 3, and 4. The average corrected distance visual acuity (CDVA) with spectacles was 20/80, with a range of 20/200 to 20/40. With the use of mSCLs, CDVA improved to an average of 20/25, ranging from 20/40 to 20/16. The mean visual acuity improvement observed was five optotype lines, with a range of 3 to 7 lines. CONCLUSION: Corneas with scars often exhibit increased higher-order aberrations (HOA), and affected patients not only experience reduced vision but also suffer from seriously reduced optical quality and optical phenomena such as photophobia. Utilizing mSCLs in such individuals can significantly enhance visual acuity and improve optical side effects resulting from corneal opacity and irregularity.

Soft Contact Lens Engraving Characterization by Wavefront Holoscopy.

Permanent engravings on contact lenses provide information about the manufacturing process and lens positioning when they are placed on the eye. The inspection of their morphological characteristics is important, since they can affect the user's comfort and deposit adhesion. Therefore, an inverted wavefront holoscope (a lensless microscope based on Gabor's principle of in-line digital holography) is explored for the characterization of the permanent marks of soft contact lenses. The device, based on an in-line transmission configuration, uses a partially coherent laser source to illuminate the soft contact lens placed in a cuvette filled with a saline solution for lens preservation. Holograms were recorded on a digital sensor and reconstructed by back propagation to the image plane based on the angular spectrum method. In addition, a phase-retrieval algorithm was used to enhance the quality of the recovered images. The instrument was experimentally validated through a calibration process in terms of spatial resolution and thickness estimation, showing values that perfectly agree with those that were theoretically expected. Finally, phase maps of different engravings for three commercial soft contact lenses were successfully reconstructed, validating the inverted wavefront holoscope as a potential instrument for the characterization of the permanent marks of soft contact lenses. To improve the final image quality of reconstructions, the geometry of lenses should be considered to avoid induced aberration effects.

Changes in bulbar conjunctival microcirculation and microvasculature during short-term scleral lens wearing and their associated factors.

OBJECTIVE: To explore the changes in microcirculation and microvasculature of the bulbar conjunctiva during the short-term wearing of the scleral lenses (ScCL). And investigate the factors affecting the microcirculation and microvasculature of the bulbar conjunctiva. METHODS: In this prospective cross-sectional study, functional slit lamp biomicroscopy (FSLB) was used to image the ocular surface microcirculation and microvascular images at two different sites (under the area of ScCL and outside of the area of ScCL) before (baseline) and during the wearing of ScCL at 0 h, 1 h, 2 h and 3 h. Anterior segment optical coherence tomography (AS-OCT) (RTVue, Optovue Inc, USA) was also used to image central post-lens tear film (PoLTF) and the morphology changes of the conjunctiva under the landing zone at the same time period. The semi-automatic quantification of microcirculation and microvasculature including vessel density (Dbox), vessel diameter (D), axial blood flow velocity (Va) and blood flow volume (Q). And the morphological changes of conjunctiva and PoLTF fogging grading were evaluated manually. The changes in the microcirculation and microvasculature of the ocular surface, PoLTF fogging grade and conjunctival morphology were compared before and during the ScCL wearing at different time periods, and the relationship between them was analyzed. RESULTS: Nineteen eyes (11 right eyes, 8 left eyes) were analyzed in this study. Outside of the area of ScCL, the Dbox before wearing lenses was less than that at 0 h (P = 0.041). The Q at baseline was greater than that after 1 h ScCL wearing (P = 0.026). Under the area of the ScCL, the Q at 1 h was less than that at baseline and 3 h. During the ScCL wearing, statistically significant conjunctival morphology changes were found among different time stages (baseline (0 µm), 0 h (113.18 µm), 2 h (138.97 µm), 3 h (143.83 µm) (all P ＜0.05). Outside the area of the ScCL, the morphology changes of the conjunctiva were negatively correlated with the changes of Va (P＜0.001,r = -0.471) and Q (P = 0.003,r = -0.348),but positively correlated with the Dbox (P = 0.001,r = 0.386). Under the area of ScCL, the morphology changes of the conjunctiva were negatively correlated with the Q (P = 0.012, r = -0.291). The fogging grade was positively correlated with the Q under the area of the ScCL (P = 0.005, r = 0.331). CONCLUSIONS: The microcirculation and microvasculature of the ocular surface and conjunctival morphology were changed after wearing ScCL in wearers, which indicated that the microvascular responses happened in the ScCL wearers and the severity of microvascular responses of the ocular surface related to the morphology changes of the conjunctiva. The quantification methods and findings in this study provide clues for the safety of ScCL wearing and may supervise the health of the wearer's ocular surface.

Correlation between pupillary size and depth of focus after the implantation of extended depth of focus intraocular lenses.

PURPOSE: To evaluate whether depth of focus after the implantation of extended depth of focus (EDoF) intraocular lenses (IOLs) correlates with pupillary size. METHODS: This retrospective case series study evaluated eyes undergoing cataract surgery with implantation of EDoF IOLs. At least one month postoperatively, the depth of focus (DoF) was measured to determine the correlation with pupillary size, age, anterior chamber depth (ACD), axial length (AXL), and corneal spherical aberrations (SA). RESULTS: The study evaluated 64 eyes of 49 patients. The mean depth of focus was 2.67 diopters (D). The mean preoperative photopic pupil size was 3.36 mm. A significant negative association was found between preoperative photopic pupil size and depth of focus (r = 0.30, Pearson's correlation coefficient) and between preoperative mesopic pupil size and depth of focus (r = 0.274, Pearson's correlation coefficient).

New Device for the Correction of Aphakia Without Capsular Support.

PURPOSE: This study describes a prototype developed for aphakia without capsular support (AWCS) and its proof of concept. METHODS: This descriptive study used a 3D software to create and analyze virtual prototypes before manufacturing. A nylon-6/nylon-6.6 copolymer filament and a 3D printer were used for prototyping. A device implantation technique was developed using a 23-gauge hypodermic needle. Two opposing markings, 2 mm posterior to the limbus, were made to determine the location of the scleral punctures and the final position of the device. After adequate centralization and positioning of the device, its haptics were cut and cauterized to generate thermal modeling of the extremity and allow the thickening of the tips (flange), serving as an anchoring mechanism to the sclera. The efficacy and adequacy of the technique and device were then evaluated. RESULTS: Vitreous tissue extrusion was not observed during the sclerotomy. The device was well fixed to the sclera; however, adequate IOL stability and centralization still needed to be achieved. The surgeon evaluated the adequacy of all the other devices' characteristics. CONCLUSIONS: The development of a technology prototype for correcting AWCS was possible. Although the proposed prototype met most of the established concept guidelines, the stability of the IOL position remains challenging.

Compatibility of a New Ocular Surface Dye with Disposable and Bi-Weekly Soft Contact Lenses: An Experimental Study.

Ocular surface staining for assessing corneal and conjunctival epithelium integrity is typically conducted using fluorescein, lissamine green, or rose Bengal dyes. Recently, a novel vital dye, REmark®, based on riboflavin, has been proposed for ocular surface examination. In the management of corneal and ocular surface diseases (OSD), the use of contact lenses is integral to therapeutic strategies. This study explores the compatibility of REmark® with four different types of disposable or bi-weekly soft contact lenses. Morphological variations observed under stereomicroscopy and ultraviolet (UV) ray transmittance in the visible spectrum (VIS) were evaluated at 2 and 4 h post-immersion of the contact lenses in both the original fluid and the new dye. The findings indicate no significant differences between the group treated with the original liquid and those immersed in REmark®, except for a yellow hue observed in the latter group, which dissipates after 8 h in physiological solution. This study highlights the potential of utilizing the new vital dye for ophthalmologic examinations even in the presence of applied soft contact lenses, offering a promising avenue for improved diagnostic practices and patient comfort.

Performance-Enhanced Piezoelectric Micromachined Ultrasonic Transducers by PDMS Acoustic Lens Design.

This paper delves into enhancing the performance of ScAlN-based Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) through the implementation of Polydimethylsiloxane (PDMS) acoustic lenses. The PMUT, encapsulated in PDMS, underwent thorough characterization through the utilization of an industry-standard hydrophone calibration instrument. The experimental results showed that the ScAlN-based PMUT with the PDMS lenses achieved an impressive sensitivity of -160 dB (re: 1 V/µPa), an improvement of more than 8 dB compared to the PMUT with an equivalent PDMS film. There was a noticeable improvement in the -3 dB main lobe width within the frequency response when comparing the PMUT with PDMS encapsulation, both with and without lenses. The successful fabrication of high-performance PDMS lenses proved instrumental in significantly boosting the sensitivity of the PMUT. Comprehensive performance evaluations underscored that the designed PMUT in this investigation surpassed its counterparts reported in the literature and commercially available transducers. This encouraging outcome emphasizes its substantial potential for commercial applications.

X-ray optics for the cavity-based X-ray free-electron laser.

A cavity-based X-ray free-electron laser (CBXFEL) is a possible future direction in the development of fully coherent X-ray sources. CBXFELs consist of a low-emittance electron source, a magnet system with several undulators and chicanes, and an X-ray cavity. The X-ray cavity stores and circulates X-ray pulses for repeated FEL interactions with electron pulses until the FEL reaches saturation. CBXFEL cavities require low-loss wavefront-preserving optical components: near-100%-reflectivity X-ray diamond Bragg-reflecting crystals, outcoupling devices such as thin diamond membranes or X-ray gratings, and aberration-free focusing elements. In the framework of the collaborative CBXFEL research and development project of Argonne National Laboratory, SLAC National Accelerator Laboratory and SPring-8, we report here the design, manufacturing and characterization of X-ray optical components for the CBXFEL cavity, which include high-reflectivity diamond crystal mirrors, a diamond drumhead crystal with thin membranes, beryllium refractive lenses and channel-cut Si monochromators. All the designed optical components have been fully characterized at the Advanced Photon Source to demonstrate their suitability for the CBXFEL cavity application.

Contact lenses as a potential vehicle of Candida transmission.

PURPOSE: Contact lenses can be contaminated with various microorganisms, including pathogenic yeasts of the genus Candida, which are known for their ability to adhere to abiotic surfaces, including plastic materials used for various medical purposes. Microbial contamination of the lenses can lead to infection of the wearer's eyes. The purpose of this study was to simulate the contamination of contact lenses with C. albicans and C. parapsilosis, analyze the interaction of the microorganisms with the lens material, and optimize the protocol for PCR-based analysis of the microbial agents responsible for lens contamination. METHODS: Hilafilcon lenses were exposed to C. albicans and C. parapsilosis cultures, washed, and examined for their ability to further spread the contamination. Scanning electron microscopy was used to analyze the attachment of yeast cells to the lenses. Infrared spectroscopy was used to examine the potential changes in the lens material due to Candida contamination. The protocol for DNA isolation from contaminated lenses was established to enable PCR analysis of microbes attached to the lenses. RESULTS: Hilafilcon lenses contaminated with Candida were able to spread the contamination even after washing with saline or with a commercial cleaning solution. In the present experimental settings, the yeasts did not grow into the lenses but began to form biofilms on the surface. However, the ability of the lenses to retain water was altered. The PCR-based protocol could be used to help identify the type of contamination of contact lenses. CONCLUSION: Once contaminated with Candida albicans or Candida parapsilosis, Hilafilcon contact lenses are difficult to clean. Yeasts began to form biofilms on lens surfaces.

Drug-Modified Contact Lenses-Properties, Release Kinetics, and Stability of Active Substances with Particular Emphasis on Cyclosporine A: A Review.

The following review focuses on the manufacturing and parameterizing of ocular drug delivery systems (DDS) using polymeric materials to create soft contact lenses. It discusses the types of drugs embedded into contact lenses, the various polymeric materials used in their production, methods for assessing the mechanical properties of polymers, and techniques for studying drug release kinetics. The article also explores strategies for investigating the stability of active substances released from contact lenses. It specifically emphasizes the production of soft contact lenses modified with Cyclosporine A (CyA) for the topical treatment of specific ocular conditions. The review pays attention to methods for monitoring the stability of Cyclosporine A within the discussed DDS, as well as investigating the influence of polymer matrix type on the stability and release of CyA.

Stereoacuity and Aniseikonia: Evaluation Before and After Bilateral Implantation of Three Types of Presbyopia-Correcting Intraocular Lenses in Uncomplicated Phacoemulsification with Due Consideration of Interocular Differences in Higher Order Aberrations, Axial Lengths, Refractive Errors, and Acuities.

Purpose: To determine if the changes in stereoacuity and aniseikonia, following bilateral implantation of presbyopia correcting intraocular lenses could be predicted from preoperative measurements of higher order aberrations (HOAs), axial lengths (AL), refractive errors (RE) and corrected visual acuities (CVAs). Patients and Methods: Stereoacuity (Randot tests, @6m & 40cm, in steps of 20 arcsecs") vertical and horizontal aniseikonia (Awaya test @6m, in steps of 1%) with best correction and HOAs (Shack-Hartmann aberrometer) were measured before, 3 and 6 months after uncomplicated bilateral phacoemulsification. Twenty patients (I) underwent a mix-and-match procedure (Tecnis MF, ZKB00 in one eye and ZLB00 in the other), 17 (II) were implanted with a trifocal (AT LISA 839 triMP) and 18 (III) with a one-piece diffractive (Synergy OU) intraocular lens. The resultant aniseikonia (AR) of vertical and horizontal pairs of aniseikonia measurements was calculated using the Pythagorean theorem. Twenty untreated age/gender matched cases were recruited as controls (IV). Results: The key results (p < 0.001) were a) stereoacuity at distance (SAD) and near (SAN) improved, AR reduced in groups I, II & III remaining unchanged in group IV; b) some significant intergroup differences in SAD, SAN & AR were detected at postop; c) at 6 months postop, changes (Δ=pre- minus postoperative value) correlated with preoperative values (x). Linear regression revealed, I ΔSAD=0.66x-57.47 [0.832, ±66.4], ΔSAN=0.96x-34.59 [0.821, ±16.9], ΔAR=0.93AR-2.12 [0.795, ±1.4] II ΔSAD=0.79x-62.91 [0.916, ±38.1], ΔSAN=0.96x-31.49 [0.892, ±8.0], ΔAR=0.91AR-0.91 [0.839, ±1.3] III ΔSAD=0.67x-35.50 [0.991, ±23.7], ΔSAN=0.88x-38.51[0.988, ±10.6], ΔAR=0.86AR-0.96 [0.900, ±1.3]. Figures in parentheses are the corresponding rs and ±limits of agreement between actual and estimated values. Definitive overarching associations connecting interocular differences in HOAs, AL, RE, and CVAs with SAD, SAN and AR were not found. Conclusion: Changes in stereoacuity and aniseikonia can be predicted using preoperative values. ΔSAN can be predicted within ±1, and ΔAR within ±2, scale divisions. In group III ΔSAD can be predicted within ±1, and in group I ±3, scale divisions.

The efficacy of orthokeratology lenses with smaller back optic zone diameter in myopia control. A meta-analysis.

PURPOSE: This study was conducted to determine whether orthokeratology (OK) lenses with a smaller back optic zone diameter (BOZD) could exhibit stronger myopia control effects. METHOD: A meta-analysis was registered in PROSPERO (CRD42023408184). A comprehensive systematic database search was conducted, encompassing PubMed, Cochrane Library, EMBASE, MEDLINE, Web of Science, Ovid, CNKI and CBM, to identify relevant studies up to 25 March 2023. The primary inclusion criteria for this meta-analysis were studies that investigated the myopia control effect of OK lenses with a small optical treatment area (≤5 mm). To assess the quality of the retrieved articles, two researchers evaluated them using the Cochrane bias risk assessment criteria. The primary outcome measures were the changes in axial length (AL) and refractive error, using the weighted mean differences (WMD) and 95% confidence intervals (CI) to assess differences between small and traditional back optical treatment zone groups in terms of these outcomes. RESULTS: The analysis encompassed five eligible studies, with a 1 year duration. The average difference in AL between the groups was 0.12 mm (WMD = -0.12, 95% CI [-0.16, -0.09], p < 0.00001). Likewise, the average difference in refractive error between the two groups was 0.44 D (WMD = 0.44, 95% CI [0.30, 0.57], p < 0.00001). None of the studies reported severe adverse events. CONCLUSIONS: Current evidence suggests that OK lenses with smaller back optical treatment zone are more effective in preventing myopia progression than traditional lenses. However, a longer-term evaluation is warranted.

Creating realistic anterior segment optical coherence tomography images using generative adversarial networks.

AIMS: To develop a generative adversarial network (GAN) capable of generating realistic high-resolution anterior segment optical coherence tomography (AS-OCT) images. METHODS: This study included 142 628 AS-OCT B-scans from the American University of Beirut Medical Center. The Style and WAvelet based GAN architecture was trained to generate realistic AS-OCT images and was evaluated through the Fréchet Inception Distance (FID) Score and a blinded assessment by three refractive surgeons who were asked to distinguish between real and generated images. To assess the suitability of the generated images for machine learning tasks, a convolutional neural network (CNN) was trained using a dataset of real and generated images over a classification task. The generated AS-OCT images were then upsampled using an enhanced super-resolution GAN (ESRGAN) to achieve high resolution. RESULTS: The generated images exhibited visual and quantitative similarity to real AS-OCT images. Quantitative similarity assessed using FID scored an average of 6.32. Surgeons scored 51.7% in identifying real versus generated images which was not significantly better than chance (p value >0.3). The CNN accuracy improved from 78% to 100% when synthetic images were added to the dataset. The ESRGAN upsampled images were objectively more realistic and accurate compared with traditional upsampling techniques by scoring a lower Learned Perceptual Image Patch Similarity of 0.0905 compared with 0.4244 of bicubic interpolation. CONCLUSIONS: This study successfully developed and leveraged GANs capable of generating high-definition synthetic AS-OCT images that are realistic and suitable for machine learning and image analysis tasks.

Effectivity and safety of trifocal intraocular lenses and capsular tension rings implantation for cataract patients with axial high myopia.

AIM: To assess effectivity and safety of trifocal intraocular lenses (IOLs) and capsular tension rings in treating cataract patients with axial high myopia. METHODS: A prospective nonrandomized controlled clinical trial was conducted. Totally 98 eyes (74 patients) who underwent femtosecond laser-assisted cataract surgery (FLACS) with trifocal IOLs were enrolled in the study and followed up for 2y after surgery: 46 eyes (33 patients) with capsular tension ring implantation in the long axial lengths (AL) group (260.05). The dysfunctional lens index and total modulation transfer function (MTF) average height were similar between the two groups. The postoperative internal coma aberrations in the axial high myopia eyes were significantly higher than that in the normal AL group (P<0.05). The total satisfaction score in the long AL group (91.32±2.76) was slightly higher than that in the normal AL group (90.36±3.47), but there was no difference (P=0.136). A statistically negative correlation was found between corrected distance visual acuity (CDVA) and dysfunctional lens index (r=-0.382, P=0.009), and between CDVA and the total MTF average height (r=-0.374, P=0.01). But there was no significant correlation between CDVA and total satisfaction score (r=0.059, P=0.696). Postoperative complications mainly presented as posterior capsular opacity (PCO), retinal detachment and cystoid macular edema. There was no difference in the incidence of fundus disease (6.5% vs 3.8%, P=0.663) or PCO (17.4% vs 7.7%, P=0.217) between the two groups at two years. CONCLUSION: The utilization of trifocal IOL and capsular tension ring implantation is beneficial for cataract patients with axial high myopia undergoing FLACS. This approach not only ensures excellent subjective feelings and objective visual quality, but also does not increase the incidence of postoperative complications.