bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of cold thermosensitive trigeminal neurons that innervate the cornea
Authors: Diaz‐Tahoces Ariadna , Aleixandre‐Carrera Fernando , Velasco Enrique , Acosta M. Carmen , Gallar Juana
Published: January 2025

Aims/Purpose: To electrophysiologically characterize the populations of thermosensitive trigeminal neurons that innervate the cornea based on their response to cooling.

Methods: The activity of trigeminal ganglion neurons was recorded in anesthetized Wistar rats using epoxylite‐insulated W microelectrodes inserted at specific stereotaxic coordinates. Saline drops at different temperatures were instilled on the cornea to change corneal temperature, which was constantly recorded with a high‐speed thermal probe. Spontaneous activity without intended stimulation (background activity, BA) and the peak frequency evoked by cold saline instillation (PA) were recorded and analyzed in 22 corneal cold thermosensitive neurons. Parametric or non‐parametric statistical tests were used as needed.

Results: Based on their BA, hierarchical clustering segregated the recorded cold thermoreceptor neurons into two groups: High Background (HB; those with BA equal or higher than 5 imp·s‐1) and Low Background (LB; those with BA lower than 5 imp·s‐1). HB cold thermosensitive neurons robustly increased their firing frequency when detecting mild cold stimuli (), being PA proportionally to ΔT (p < 0.05). For corneal ΔT between ‐1° and ‐14°C, PA of HB was maximal regardless of the stimulus intensity. In LB neurons, PA response increased proportionally to the cold stimulus intensity for ΔT between 0‐1° and ‐14°C, and the response to ΔT ‐3°C was significantly different from basal firing.

Conclusions: Two subpopulations of corneal cold sensory neurons have been identified in the ophthalmic branch of the trigeminal ganglion. These neurons, which have high background activity, are sensitive to cold temperatures and can detect small changes in corneal temperature. We propose that these neurons detect the temperature drop between blinks and, in turn, trigger the so‐called spontaneous blink.

(Supported by PID2020‐115934RB‐I00 from DOI: MCIN/AEI/10.13039/50110001103, Spain, and CIPROM/2021/48 from Generalitat Valenciana, Spain).
Anti‐inflammatory effects of thealoz duo eye drops on the ocular surface of dry eye patients
Authors: Fomo Kristian Nzogang , Perumal Natarajan , Hadji Majd , Yang Jie , Wolters Dominik , Pfeiffer Norbert , Grus Franz
Published: January 2025

Aims/Purpose: Dry eye syndrome (DES) is a complex pathological condition of the ocular surface characterized by a disturbance of tear film due to lack of tears or excessive tear evaporation. Topical application of medicated eye drops has been shown to be an effective treatment for this disease. In a previous study, Thealoz® Duo eye drops (Laboratoires Thea, France) were demonstrated to significantly enhance vision‐related functions and to inhibit inflammation in patients with DES. The objective of this study was to provide further insight into the efficacy of Thealoz® Duo eye drops by analyzing the expression profiles of marker proteins in the tears of dry eye patients using microarray technology.

Methods: A total of 58 candidates were divided into two groups: those with dry eye (DES, N = 35) and those with healthy eyes (CTRL, N = 23). Thealoz® Duo (hyaluronic acid 0.15% and trehalose 3%) was administered only to the DES patients. Tear samples were collected from each individual in both groups at three distinct time points: prior to treatment (day 0, designated T1), on day 28 ± 4 (T2) and on day 56 ± 4 (T3) following the administration of Thealoz® Duo. Thereafter, all samples underwent analysis of the expression of targeted proteins (e.g., APOA1, S100A8, TNFa, FBP1, IL2, IL8, IL17A, IL1RN, SERPINA1 and MMP9) using microarray technology.

Results: The data analysis revealed a significant increase in all maker proteins in DES vs. CTRL at T1 (p < 0.05). Furthermore, the data demonstrated that the application of Thealoz® Duo resulted in a decrease in the expression of inflammatory markers in DES vs. CTRL at T2 and T3.

Conclusions: The present findings provide further evidence supporting the potential of Thealoz® Duo to improve the visual outcomes by mitigating the inflammation on the ocular surface in patients with DES.
Revisiting fuchs endothelial corneal dystrophy clinical classification using innovative high‐resolution, far‐red, reflexion free retroillumination
Authors: Thuret Gilles , Dorado‐Cortez Oliver , Poinard Sylvain , Ain Anthony , Vaitinadapoule Hanielle , Trone Marie‐Caroline , Lepine Thierry , Gain Philippe
Published: January 2025

Purpose: Fuchs endothelial corneal dystrophy (FEDC) is by far the most common corneal endothelial diseases in Western countries, and 50% of keratoplasties are carried out to treat endothelial diseases. New treatments are also emerging (Descemetorhexis only, rock‐inhibitors, mTor‐inhibitors, FGF‐1). It will therefore soon be vital to be able to determine the stage of each patient in a simple and reliable way, in order to personalize treatment. Visual acuity, retroillumination, specular microscopy and thickness mapping are the 4 pillars of the examination. However, current retro‐illumination images are of insufficient quality. Aim: to present the first series of FECD observed using new‐generation retroillumination.

Methods: We developed a prototype retroilluminator by modifying a slit lamp with the aim of obtaining high‐resolution images, without parasitic reflection and without dazzling the patient. We then prospectively photographed 200 FECD patients. The images were then classified by 3 independent observers according to the modified Krachmer classification, which is the most widely used in the literature: it distinguishes patients according to the number of Guttae, the size of the area of confluent Guttae and the presence of oedema.

Results: The prototype produced clear, glare‐free images in over 95% of cases. Persistent reflections were observed exclusively in pseudophakic patients. The high resolution made it possible to observe all the Guttae and to challenge Krachmer's grade 2 classification (more than 12 non‐confluent drops), which included a major diversity of patients, some of whom had thousands of non‐confluent Guttae. We also highlighted for the first time to our knowledge 2 new elements: the high frequency of radial alignment of Guttae, often over 360°, and the presence of Guttae in the periphery of the endothelium, suggesting that a cell migration anomaly is involved.

Conclusions: Innovative retroillumination images challenge Krachmer's classification by providing exceptional precision. They will make it easier to distinguish between sub‐groups of patients with different visual repercussions and evolutionary profiles. Easy to use, this new device should help to improve both our understanding of FECD and its routine management.
Understanding structural changes in keratoconus: Anterior scleral and choroidal thickness analysis using swept source optical coherence tomography
Authors: Hassairi Asma , Ahmed Chebil , Mehdi Oueslati , Limaiem Rim
Published: January 2025

Aims/Purpose: The study aims to investigate the anterior scleral thickness (AST) profile and choroidal thickness (CT) variations in keratoconus (KC) patients compared to healthy controls, with the objective of providing a comprehensive understanding of ocular structural changes in KC.

Methods: A cross‐sectional case‐control study was conducted, involving 46 eyes: 23 KC eyes and 23 age‐ and axial‐length‐matched healthy eyes. Anterior scleral thickness (AST) was evaluated at three scleral eccentricities (1, 3, and 6 mm from the scleral spur) across four scleral zones (nasal, temporal, superior, and inferior) using the anterior segment module of the Triton SS OCT (Topcon, Tokyo, Japan). Additionally, choroidal thickness profiles in KC patients were derived from SS‐OCT scans. Comparative analyses were conducted to assess thickness variations within and between groups.

Results: In KC eyes, AST exhibited significant variations across several meridians, particularly over the temporal and inferior meridians, in comparison to healthy eyes. Although AST profiles did not differ significantly between groups, differences in inferior‐superior thickness asymmetry were observed, particularly in subclinical KC eyes. Choroidal thickness in KC patients was notably greater compared to healthy controls and displayed a declining trend with age.

Conclusions: Keratoconus eyes manifest substantial anterior scleral thickness variations across eccentricities, indicating structural alterations in the paracentral sclera. While AST profiles did not reveal significant differences between KC and healthy eyes, observed asymmetry disparities in thickness imply vertical meridian scleral changes in KC, warranting further exploration. Additionally, the increased choroidal thickness in KC patients, coupled with its age‐related decrease, suggests potential implications for understanding KC pathogenesis.
Effect of insulin eye drops for refractory persistent corneal epithelial defects
Authors: Valyi Zsuzsanna , Relvas Lia Judice De Menezes , Makhoul Maxime , Willermain François
Published: January 2025

Aims/Purpose: The aim of this study is to investigate the effect of insulin eye drops on corneal wound healing in persistent epithelial defects (PEDs) resistant to standard treatment

Methods: This retrospective monocentric study is based on a clinical chart review of patients with PEDs treated with insulin eyedrops between April 2022 and December 2023. All patients had received priorly the current standard therapy for PEDs ranging from bandage contact lenses and punctum plugs to autologous serum and amniotic membrane grafts without any clinical response. The effect of topical insulin treatment was evaluated by the rate and time of corneal reepithelization and recurrence. Side effects and clinical factors that may influence the outcome of the treatment were also analyzed.

Results: In total 54 eyes of 50 patients were included in this study. Previous and unsuccessful standard PED treatment time ranged days between 216.1 ± 49.9 days. Reepithelization with insulin eyedrops occurred in 49 eyes (90.8%) after 22.4 13.6 days. Complete wound closure was observed in 31 eyes (57.5%) and partial reepithelization in 18 eyes (33.3%). Five eyes (9.2%) showed no improvement at all. Among those eyes with a complete reepithelization 11 (35.5%) had a recurrence after stopping the treatment. Insulin drops were less effective in patients with PEDs of inflammatory or auto‐immune origin, and those treated with corticosteroids and amniotic membrane grafts. No side effects were observed.

Conclusions: Insulin eye drops for PEDs seem to be a safe and effective treatment option. Further prospective clinical studies are needed to confirm these promising results.
Surgical detachment of irido‐ and lenticulocorneal adhesions in Peters anomaly
Authors: Kotola Elsa‐Leea , Turunen Joni A. , Lindahl Päivi , Krootila Kari , Majander Anna
Published: January 2025

Aims/Purpose: To report anatomical and visual acuity outcome of surgical detachment of iridocorneal or lenticulocorneal adhesions in pediatric patients with Peters anomaly.

Methods: An observational study of pediatric patients with Peters anomaly treated with surgical detachment of iridocorneal or lenticulocorneal adhesions between 2011 and 2024 at the Helsinki University Hospital. Ocular and extraocular diagnoses, age, sex, best corrected visual acuity (BCVA), intraocular pressure, ocular surgeries, surgical complications, family history, genetics and anterior segment optical coherence tomography data were collected from the medical records.

Results: Fourteen eyes from nine patients underwent the surgery. The median age at the time of surgery was 14 months (range 5‐56) and the median follow‐up period was 156 months (range 6‐166). Of the treated eyes, 12 had iridocorneal adhesions, while two eyes also had lenticulocorneal adhesions. No surgical complications were reported. Anterior segment anatomy and corneal clarity were stable or improved during the follow‐up. Among the fourteen eyes, three eyes achieved a BCVA better than 0.3 (Snellen decimal), while none had a BCVA worse than 0.05. BCVA was not available for three treated eyes due to the patients' young age. The following additional ocular conditions were recorded: microphthalmia, cataract, glaucoma, retinal degeneration, nystagmus, corectopia and strabismus. Four eyes underwent further ocular surgeries, such as cataract surgery with intraocular lens implantation, anterior vitrectomy, pupilloplasty, and temporal iridectomy. Five patients had systemic findings. Pathogenic variants in the PITX3 and RARB genes were detected in three patients and one patient, respectively.

Conclusions: This study demonstrates that surgical detachment of irido‐ and even lenticulocorneal adhesions in Peters anomaly is safe and results stable anatomical and visual acuity outcome over the period of critical visual development.
Extraction and quantification of human tear proteins sampled by schirmer test strips. A validated and standardized method
Authors: Porru Emanuele , Ciavarella Carmen , Comito Rossana , Astolfi Gloria , Violante Francesco , Versura Piera
Published: January 2025

Aims/Purpose: The identification of biomarkers in tears help in diagnosis and management of ocular diseases, and beyond [1]. We aimed to develop and validate a method for extracting and quantifying proteins from human tears collected using Schirmer test strips, which are typically discarded after clinical use.

Methods: Tears from 18 healthy volunteers were collected by aspiration with a micropipette and by paper strips after use for Schirmer test (5 minutes at closed eyes). Aspirated tears were centrifuged and stored at ‐80°C until processing. Tears from strips were eluted using a developed extraction buffer (ABC 100mM, Chaps X‐100 0.25%), and both samples were analyzed using the Agilent 2100 Bioanalyzer. The conversion of the wetted portion (mm) into volume tears (μL) was accurately assessed. The method's accuracy, precision, and sensitivity were estimated, and it was further validated using mass spectrometry.

Results: The elution buffer enabled high recovery values for proteins such as albumin, lysozyme, zinc‐alpha2‐glycoprotein (ZAG), lipocalin A, transferrin, and lactoferrin, as compared to the results from the aspirated tears. The method demonstrated high accuracy (bias% < 10%), precision (CV% < 10%), and sensitivity, with a matrix effect of less than 5% for the studied proteins. The recovery rates were greater than 90% for lysozyme and albumin, and greater than 80% for ZAG, lipocalin, transferrin, and lactoferrin. Validation using mass spectrometry confirmed the reliability of protein identifications and quantifications.

Conclusions: The developed protocol is simple, cost‐effective, and achieves significant protein recovery, making it suitable for routine clinical analyses in the clinical setting. The method's validation through mass spectrometry highlights its robustness and applicability for identifying and quantifying tear proteins.

Reference

Rentka, Aniko, et al. "Evaluation of commonly used tear sampling methods and their relevance in subsequent biochemical analysis." Annals of Clinical Biochemistry 54.5 (2017): 521‐529.
Comparative efficacy of receptor tyrosine kinase inhibitors in a mouse model of alkali burn‐induced corneal neovascularization
Authors: Gladkauskas Titas , Rundgren Ida , Cristea Ileana , Rødahl Eyvind , Bredrup Cecilie
Published: January 2025

Aims/Purpose: This study evaluates the efficacy of topical dasatinib and axitinib for treating experimentally induced corneal neovascularization (CNV) in a mouse alkali burn model, comparing these treatments to established therapies like dexamethasone and bevacizumab. The study aims to determine which treatment provides superior efficacy in inhibiting CNV in this model.

Methods: Thirty‐six C57BL/6; 129Sv mice underwent a standardized alkali burn to induce CNV in both eyes using a paper disc soaked in 1M NaOH. The mice were randomly assigned to one of six treatment groups: saline (0.9% sodium chloride), DMSO (5%), dexamethasone (0.1%), bevacizumab (0.5%), dasatinib (0.5%), or axitinib (0.5%). Treatments were applied topically three times daily. CNV assessments, including corneal neovascularization area (CNA), vessel length index (VLI), and limbus vasculature thickness, were conducted post‐mortem using corneal flat‐mounts stained with CD31 antibody for immunohistochemistry.

Results: Dexamethasone proved the most effective in inhibiting alkali burn‐induced CNA (p < 0.0001), with bevacizumab showing comparable efficacy (p < 0.001). Axitinib also effectively reduced CNA (p < 0.001) and VLI (p < 0.01). In contrast, dasatinib did not significantly reduce CNA (p = 0.74) or VLI (p = 0.98).

Conclusions: While dexamethasone was most effective, both bevacizumab and axitinib successfully reduced CNA, with axitinib additionally decreasing VLI. Axitinib has a broad‐spectrum inhibition of vascular endothelial growth factor receptors 1, 2, and 3 (VEGFR1, VEGFR2, VEGFR3), and platelet‐derived growth factor receptor β (PDGFRβ). This may offer superior benefits compared to narrower‐spectrum TKIs like dasatinib, which primarily target PDGFRβ and fibroblast growth factor receptor (FGFR). The results highlight the effectiveness of targeting the VEGF‐VEGFR pathway for managing corneal neovascularization, presenting a viable option for patients who are sensitive to steroids.
Engineering multicellular organoid for corneal niche modelling and regenerative therapies
Authors: Gulzar Ayesha , Goktan Isilay , Yalcin Esra , Sahin Afsun , Kizilel Seda
Published: January 2025

Purpose: The corneal niche is composed of various cell types, including limbal stem cells (LSCs), corneal epithelial cells (CECs), and neuronal cells. LSCs are pivotal for corneal epithelial regeneration, CECs maintain the corneal transparency, and neuronal cells contribute to sensory and trophic functions. Despite advances in corneal research, the interplay among these cell types within the corneal niche remains insufficiently understood. This study aims to engineer organoids combining LSCs, CECs, and neuronal cells to create a robust model for studying the corneal niche and to explore their transplantation potential.

Methods: LSCs, CECs, and SHSY‐5Y neuronal cells were separately seeded in their growth mediums. After reaching confluency, cells were trypsinized and co‐cultured to form multicellular organoids using the hanging drop technique [1]. Various parameters including cell number, cell‐cell ratio and incubation time were optimized for organoid formation. The organoids were characterized for their cellular composition, structural integrity, and viability using immunohistochemical staining and confocal microscopy. Functional assays, including cell proliferation and differentiation markers, were performed to assess their regenerative potential.

Results: To determine the optimal conditions for organoid formation, we experimented with different ratios of LSCs, CECs, and SHSY‐5Y cells, specifically 1: 1: 1, 2: 2: 1, 4: 2: 1, and 8: 2: 1. The results showed that the engineered organoids formed under all four ratios exhibited a well‐organized structure with high viability for a week. Functional assays including Ki67 and CD44 revealed active proliferation and differentiation, indicating the regenerative potential of the spheroids.

Conclusions: This study underscores the potential use of tri‐coculture organoid as a promising therapeutic strategy for limbal stem cells deficiency and a valuable tool for investigating the complex cellular interactions within the corneal environment.

Reference

M. Birgul Akolpoglu, Yasemin Inceoglu, Seda Kizilel, An all‐aqueous approach for physical immobilization of PEG‐lipid microgels on organoid surfaces. Colloids and Surfaces B: Biointerfaces, Volume 186, 2020, 110708, ISSN 0927‐7765, https://doi.org/10.1016/j.colsurfb.2019.110708.
Efficacy and tolerability of a new riboflavin‐based dye compared to double staining with fluorescein and lissamine green in the evaluation of corneal‐conjunctival epithelial defects: Preliminary data
Authors: Troisi Mario , Caruso Ciro , Troisi Salvatore , Bellucci Carlo , Costagliola Ciro
Published: January 2025

Aims/Purpose: To evaluate the diagnostic sensitivity and tolerability of a new 0.5% riboflavin vital dye (Remark®, Servimed Ind. SpA, Rome, IT), on corneal and conjunctival epithelial defects, compared to standard stains (fluorescein and lissamine green).

Methods: 56 eyes of 28 patients (15M, 13F; mean age 51.3 ± 9) with bilateral ocular surface epithelial defects were evaluated. In one eye of each patient selected randomly, after the application in the conjunctival fornix of Lissamine Green Ophthalmic strip (GreenGloTM, Stag Medical, Raleigh, NC) moistened with an eye drop of fluorescein 0.5% solution (Fluorofta®, Fidia Farmaceutici S.p.A., Abano Terme, IT), SLE was carried out using cobalt blue filter to evaluate corneal staining and white filter for the conjunctiva. Grading was assessed according to NEI score. After 30 minutes and washing with 5 drops of saline instilled every 10 minutes, a similar evaluation was carried out with cobalt blue light and yellow filter in the eyepiece after instillation of Remark® (Group A). The same evaluation was performed in the fellow eyes by reversing the sequence of dyes (Group B). A symptom score questionnaire was obtained for each group.

Results: The average corneal NEI score was 3.32 (Gr. A) and 3.12 (Gr. B) for double staining, 3.38 (Gr. A) and 3.22 (Gr. B) for Remark®; average conjunctival score was 5.12 (Gr. A)/4.88 (Gr. B) for double staining and 5.04 (Gr. A)/4.76 (Gr.B) for Remark®. The differences between the two staining methods were not statistically significant in both groups (p > 0.05). In no case an intolerance to the products used has been recorded.

Conclusions: The new riboflavin‐based dye was effective in detecting both corneal and conjunctival defects, without statistically significant differences compared to double staining, and with a good tolerability. The study highlights the potential of this new dye overcoming the limit of the need of 2 different dyes, reducing costs and evaluation time.
In‐situ printing of GelMa‐based hydrogels for cornea regeneration
Authors: Goodarzi Hamid , Om Boda , Griffith May , Boutopoulos Christos
Published: January 2025

Aims/Purpose: Corneal perforation is a medical emergency that can lead to blindness. Treatment options encompass cyanoacrylate or fibrin glue, both linked to side effects, including cytotoxicity. Gelatin methacryloyl‐based biomaterials offer an alternative to these adhesives [1, 2]. Achieving optical clarity and smooth surface integrity is crucial for the restoration of vision in treated corneal wounds.

Methods: Currently, the delivery of corneal biomaterials utilizes standard syringe systems, which lack the accuracy to reconstruct the cornea's shape. Therefore, the use of a laser bioprinting technology, developed in the Boutopoulos lab [3], for achieving precise in‐situ corneal wound repair was examined. We used a photocrosslinkable ink comprising Gelatin Methacryloyl (GelMa), hydroxyethyl acrylate (HEA), and Lithium phenyl‐2,4,6‐trimethylbenzoylphosphinate (LAP) as a photoinitiator.

Results: Printability was optimized by generating nanoliter‐volume individual droplets using 230 μJ laser energy, a flow rate 20 microliter per minute, and a temperature of 37°C. Rheology, optical characterization, and bursting pressure measurements assessed its potential to seal corneal perforations. Results indicated a hydrogel storage modulus of 1.31 ± 0.31 KPa for printed LiQD cornea and a bursting pressure of 38 ± 6 mmHg when used to seal full thickness cornea perforation in cadaveric pig eyes. Optical clarity akin to the native cornea was observed (%light transmission: 93.12 ± 1.02 printed vs 92.61 ± 1.50). The OCT results showed that the LIST technique could potentially fill the corneal wounds and reconstruct the natural curvature of the wounded cornea.

Conclusions: In conclusion, a precise printing system for delivering adhesive corneal regenerative biomaterials to wounds was developed and characterized.

References

Sharifi, S., et al., 2021. 6(11): p. 3947‐3961.

Barroso, I.A., et al., 2022. 9(2).

Ebrahimi Orimi, H., et al., Sci Rep, 2020. 10(1): p. 9730.
Comparison of refractive parameters provided by a new open field aberrometer and the subjective refraction
Authors: Puche Ana Belen Plaza , Martínez‐Abad Antonio , Cantó‐Cerdán Mario , Yebana Pilar , José‐Martínez Marina , Rodriguez Alejandra , Alio Jorge
Published: January 2025

Aims/Purpose: To compare and evaluate the agreement of the refractive parameters provided by a new open field aberrometer (OFA‐Osiris CSO®) and those obtained by the subjective refraction.

Methods: It is an observational, prospective, and transversal study composed by subjects younger than 40 years‐old without ocular pathologies neither accommodation disfunction. All subjects underwent an exhaustive optometric evaluation including the subjective refraction and an ocular aberrometry with OFA‐Osiris device. The sphere, cylinder and axis were obtained from both methods being converted to polar notation using M, J0 and J45 vectors for an accurate refractive management. The refractive data provided by ocular aberrometry were extracted at 4 and 5mm of pupil diameter. The Wilcoxon sum tank test was applied for the comparison between methods and the Bland‐Altman plots were used for the agreement analysis.

Results: A total of 183 subjects of a mean age of 24.85 ± 5.19 years‐old were included. Selecting a pupil diameter of 5 mm with ocular aberrometry, the refractive measurements did not present statistical differences with the subjective method obtaining a mean M of ‐1.58 ± 2.26D and ‐1.59 ± 2.31D respectively (p: 0.228), a mean J0 of 0.03 ± 0.27D and 0.01 ± 0.26 Drespectively (p: 0.280), and a mean J45 of 0.01 ± 0.24D and 0.01 ± 0.26D respectively (p: 0.259). However, considering an aberrometric pupil diameter of 4 mm, the M vector was significantly different to the obtained by subjective refraction (‐1.49 ± 2.33D and ‐1.59 ± 2.31d respectively, p < 0.001) not presenting difference in terms of astigmatism. Bland‐Altman plots revealed limits of agreements higher than 1 diopter to refractive parameters.

Conclusions: The aberrometric refraction provided by a new open field aberrometer presented good agreement with the subjective refraction, especially considering a pupil diameter of 5mm. However, it may present clinical differences between both techniques, therefore the subjective refraction must be considered as the gold standard for the refractive evaluation.
Correlation between multifocal electroretinogram and autofluorescense in patients with ABCA4 retinopathy
Authors: Álvarez Marta Arias , Sopeña‐Pinilla Maria , Fernández‐Espinosa Guisela , Garza Inés Vicente , Orduna‐Hospital Elvira , Boned‐Murillo Ana , Díaz‐Barreda Mª. Dolores , Mena Diego Rodríguez , Pinilla Isabel
Published: January 2025

Aims/Purpose: Stargardt disease is the most common hereditary retinal dystrophy (HRD) affecting primarily the cones, typically associated with an autosomal recessive inheritance pattern, mainly due to mutations in the ABCA4 gene.

New diagnostic techniques have been introduced such as OCT, OCTA, and autofluorescence (AF). In this context, multifocal electroretinogram (mfERG) has gained importance as a diagnostic tool.

The aim of this study is to correlate the structural findings obtained through AF with the functional changes detected by mfERG in patients with ABCA4 retinopathy.

Methods: Twenty‐two eyes from patients diagnosed with Stargardt disease, confirmed by genotyping with double mutation in ABCA4, were included. The most frequent mutation was ABCA4 c.3386G > T (p.Arg1129Leu). One patient had the mutation in homozygosity, and the others in heterozygosity. The participants were evaluated using the Roland RETIscan system for mfERG, following the standardized guidelines of the International Society for Clinical Electrophysiology of Vision (ISCEV). The N1‐P1 electrical density and P1 implicit time were measured and analyzed in 5 concentric rings centered on the fovea. Additionally, a structural study was conducted using AF.

Results: The average visual acuity (VA) was 0.49 ± 0.31 (range 0.05‐0.8). The average age was 37.22 ± 19.64 years (range 10‐78). AF showed central hypofluorescence in all patients, with 5 presenting a patchy pattern. Eight patients had flecks within the arcades, of which 3 had minimal central flecks.

Patients with larger central hypofluorescent areas showed lower electrical density in the central rings. Those with flecks in the central 30° had functional alterations in ring 4 and, in some cases, in ring 5.

Conclusions: A decrease in electrical densities in the central rings was observed, correlating with larger areas of hypofluorescence on AF. The presence of flecks in the arcades correlated with a decrease in electrical density in the more peripheral rings.
Neurovascular coupling response: A follow‐up study
Authors: Jordão João , Rodrigues Sérgio , Domingues Joana , Serranho Pedro , Guimarães Pedro , Bernardes Rui
Published: January 2025

Aims/Purpose: This work aims to assess the consistency of the neurovascular coupling (NVC) response of a healthy subject group at two visits 5 months apart.

Methods: Fundus images (4x4 degrees) of the macular region (3 baseline acquisitions and 3 acquisitions each preceded by flicker stimulation) of 13 healthy adults (one eye each, age (m+/‐sd): 33.08+/‐11.4 yrs.) were acquired with the rtx1 AO camera (ImagineEyes, Orsay, France). The rtx1 was configured for a 20 second, 15Hz, and 4 μW.cm^(‐2) flicker stimulation over a 29x20 degrees area of the imaged eye fundus. Acquisitions for each subject were repeated 159+/‐17 (m+/‐sd) days later.

The lumen of retinal arterioles within the macular region was determined using custom‐developed software for the automatic segmentation of lumen‐wall interfaces. An experienced technician visually assessed all segmentations to reject subpar results. Lumen diameters were calculated from the distance between the lumen‐wall interfaces as measured perpendicular to the vessel axis along a vessel segment. NVC responses were calculated per eye as the relative difference (%) of the lumen diameter after stimulation to the respective baseline.

Results: A total of 22 out of 156 images (14%) were rejected and excluded from further analysis. NVC responses ranged from 0.21% to 8.28% (3.36+/‐2.75 % (m+/‐sd)) for the first visit and from ‐0.24% to 9.13% (3.03+/‐2.54 %) for the follow‐up. Response differences between time points ranged from ‐6.15% (8.28% to 2.13%) to 4.21% (0.98% to 5.19%), with an average (sd) of 0.34(3.03) % for the group. A paired sample Wilcoxon test between time points is not statistically significant (p = 0.650), supporting that the responses are consistent between time points.

Conclusions: The obtained results show a consistent NVC response for a 5‐month interval.
Objective measurement of accommodation in patients with an accommodating intraocular lens compared to phakic, presbyopic, and pseudophakic eyes
Authors: Eppig Timo , Seer Manuel , Müller Violetta , Schütz Saskia , Rombach Michiel , van Lawick Willem
Published: January 2025

Aims/Purpose: The restoration of accommodation after cataract surgery remains to be one of the biggest challenges in ophthalmology. Numerous concepts for restoration of accommodation have failed due to a lack of objective accommodation measurement. The purpose of this study was to demonstrate the dynamic pseudophakic accommodation in patients with an accommodative AIOL by means of an objective accommodation measurement and to compare the data with a young phakic, a presbyopic and a monofocal pseudophakic person.

Methods: We included 3 patients in the study who had a Lumina AIOL implanted in both eyes. All patients had completed at least the 6 month follow‐up. In addition, we included both eyes of 3 comparative persons with different status of the lens (phakic, presbyopic and pseudophakic). We used a binocular open‐field videorefractor (PowerRef 3, Plusoptix GmbH, Germany) to measure the change of refraction, pupil diameter and ocular convergence while patients were asked to focus on an ETDRS chart. The ETDRS chart was then continuously moved from 6m distance to 33 cm distance while the patients were asked to focus on a single letter. The resulting curves were then compared to demonstrate the objective change in refraction.

Results: The data exhibit a continuous change of binocular refraction which follows the pupil constriction and decrease of pupil distance (convergence) in the young phakic person and the AIOL patients. The maximum accommodative change was up to 2.5 D in the AIOL patients and up to 3 D in the young phakic person for a stimulus distance of 33 cm. The presbyopic patient and the monofocal pseudophakic patient showed pupil constriction and convergence but the accommodative range was less pronounced with a maximum change of 1 D.

Conclusions: The PowerRef 3 allows for an objective proof of pseudophakic accommodation in patients with an AIOL. AIOL eyes show defined change of refractive power that can be maintained constant for the time of fixation to a near target compared to presbyopic and monofocal pseudophakic eyes that show only little modulation, which can be attributed to pseudo‐accommodative effects.
Orthokeratology and myopia control: A comprehensive meta‐analysis of axial growth in children and adolescents
Authors: Queirós António , Mota‐Silva Inês , Pereira‐da‐Mota Ana Filipa
Published: January 2025

Aims/Purpose: The aim of this study was to evaluate the longitudinal effect on axial eye length in myopic children and adolescents treated with orthokeratology (OK) lenses compared to spectacles (GL), through a systematic review and meta‐analysis

Methods: We conducted a systematic search of PubMed and Google Scholar databases for randomized controlled trials and cohort studies investigated the effects of longitudinal axial length difference, using the keyword “Axial Length” AND “orthokeratology” AND “spectacles”. From the initial 91 studies, we excluded 13 review studies, 10 meta‐analysis studies, 7 systematic reviews and 37 studies that did not meet the inclusion criteria. Of the 24 selected studies, detailed information was available at 24, 18, 12, 6, 3 and 1 month, with 10, 8, 19, 17, 2 and 3 studies respectively, allowing for the comparison between 2172 eyes treated with orthokeratology and 2095 eyes with glasses.

Results: The analysis of the 24 studies (which included 59 comparisons from 1 month to 24 months) showed no statistically significant differences in initial axial length [AL(GL) = 24.39 ± 0.34 mm; AL(OK) = 24.44 ± 0.38 mm] and initial refractive error [M(GL) = ‐2.59 ± 0.70 D; M(OK) = ‐2.53 ± 0.44 D] between the two treatment groups (p > 0.565, independent samples t‐test) and for the evolution time intervals (p > 0.591, ANOVA). This analysis encompassed 4267 eyes with a mean age of 10.23 ± 1.21 years. Forest plot provided in an overall effect size of myopic defocus AL = ‐0.16 com IC 95% ‐0.19 a ‐0.14, Z = 12.71 p < 0.001. A random effects model was used considering the heterogeneity observed (I2 = 97%; p < 0.001, df = 58). There was a greater myopia control effect at 24 months (AL = ‐0.26, 95% IC ‐0.29 to ‐0.22, Z = 13.71 p < 0.001; I2 = 0%; p = 0.95) than to treatments of less than 3 months (AL = ‐0.04, 95% IC ‐0.06 to ‐0.01, Z = 2.60 p = < 0.009; I2 = 86%; p < 0.001).

Conclusions: While the treatment at 24 months shows an homogeneous behaviour among studies, shorter follow‐up times renders a larger heterogeneity and for that reason, longer follow‐up periods should be preferred to estimate a more solid effect size. Orthokeratology treatment has been shown to be effective in myopia control progression for short or longer longitudinal treatments in children and young people with spectacles comparison.
Efficacy of orthokeratology on peripheral refraction in youth: A comprehensive meta‐analysis
Authors: Queirós António , Silva‐Pinheiro Inês , Fernandes Paulo
Published: January 2025

Aims/Purpose: This study aims to determine the impact of orthokeratology lenses on relative peripheral defocus (RPD) in children and adolescents through a systematic review and meta‐analysis.

Methods: A thorough literature search was conducted using PubMed and Web‐of‐Science databases, focusing on randomized controlled trials (RCTs) and cohort studies investigating the effects of orthokeratology on peripheral refraction. The search employed the keywords "peripheral refraction" AND "orthokeratology." The inclusion criteria required studies to report spherical equivalent (M) peripheral refraction at 25° and/or 30°, including standard deviation or standard error of the mean, and present data graphically or in tables for horizontal meridian measurements before and after orthokeratology treatment. Relative peripheral refraction (RPR) was computed. From an initial pool of 133 studies, 124 were excluded for various reasons, resulting in a final sample of 9 studies. Four studies included data up to 12 months, while five provided data for less than three months, allowing separate analyses before pooling for an overall effect.

Results: The 9 studies included 3 RCTs and 6 cohort studies with 239 participants aged 6 to 30 years. The pre‐treatment refractive error was M = ‐2.48 ± 0.29D, with follow‐up periods ranging from 14 days to 1 year. All studies indicated a myopic shift at 30° Nasal (‐2.13 ± 1.05 D) and 30° Temporal (‐2.40 ± 0.47 D), averaging ‐2.27 ± 0.83D. The meta‐analysis yielded an overall myopic defocus effect size of M = ‐2.29 (95% CI ‐1.94 to ‐2.64, Z = 12.84, p < 0.001) using a random effects model due to observed heterogeneity (I2 = 63%; p < 0.001). Myopic blur induction was greater at 1 year (M = ‐2.64, 95% CI ‐2.42 to ‐2.85, Z = 24.52, p < 0.001; I2 = 0%; p = 0.84) compared to treatments under 3 months (M = ‐1.98, 95% CI ‐1.94 to ‐2.64, Z = 7.37, p < 0.001; I2 = 63%; p < 0.001).

Conclusions: The results suggest a more consistent effect with longer treatment durations, highlighting the necessity for extended follow‐up periods to achieve a reliable effect size estimate. Orthokeratology effectively induces myopic defocus at 30° eccentricity in children and adolescents over both short and long‐term treatments.
Closed‐perfusion transretinal erg (tERG) on mouse and human retinas
Authors: Saeid Sama , Pitkänen Marja , Ilonen Emma , L'Ecuyer Zia , Niskanen Jukka , Tenhu Heikki , Vinberg Frans , Koskelainen Ari
Published: January 2025

Aims: The isolated mouse and postmortem human retina can serve as a sensitive biosensor for preclinical drug testing. To facilitate testing with minimal amounts of potential drug molecules or nanostructures, we developed a closed‐perfusion tERG setup. The major challenge with small perfusate volumes was the healthiness and stability of the retina in prolonged experiments.

Methods: We conducted ex vivo tERG experiments using WT C57BL/6J and Gnat1‐/‐ mouse, and human donor retinas (Lion's Eye Bank, Utah). The isolated mouse or punches of human retinas were embedded in a specimen holder and the retina was perfused with a constant flow (5‐6 ml/min) from photoreceptor side, circulated with a peristaltic pump. Added Penicillin‐Streptomycin to prevent bacterial growth. 50 μM BaCl2 inhibited the K+ currents in Müller glial cells, and 20 μΜ D, L‐2‐amino‐4‐phosphonobutyric acid was added to isolate the rod component. Stimulated the dark‐adapted retina with 530 nm full‐field flashes. The electrical connection through the perfusate from the peristaltic pump to the specimen holder was cut off with burettes that also attenuated the pulsation from the pump. The stimulus and recording devices were remotely controlled by an automatic setup implemented with LabVIEW software.

Results: The minimum perfusate needed in our closed perfusate circulation was 50 ml. Pen‐Strep was indispensable for long recordings. With mice, rod responses were stable for more than 24 hours and rod and cone bipolar cell responses for up to 12 hours. Rod responses from human donor tissue were stable up to 12 hours. We used our setup to test the zwitterionic polymer poly (sulfobetaine methacrylate), serving as a promising material for thermoresponsive nanostructures, for possible harmful effects on mouse rod and bipolar cell functioning. No effects on rod and bipolar cell responses were observed.

Conclusions: Our method enables long, stable tERG recordings with closed perfusion on mouse and human retinas, allowing fast preclinical drug efficacy and biocompatibility testing with tiny amounts of drug molecules, materials, or nanostructures. Sulfobetaine as monomer or linear polymer did not harm rod, ON‐bipolar, or synapse functioning, suggesting the material can safely be used for constructing thermoresponsive nanostructures for drug delivery.
A new light‐adaptive lens improves contrast sensitivity when transitioning from bright to dark environments
Authors: Duarte‐Toledo Raul , Mompean Juan , Paniagua‐Diaz Alba , Lakhchaf Nacer , Kobia‐Acquah Emmanuel , Artal Pablo , Barrau Coralie
Published: January 2025

Aims/Purpose: Light‐adaptive lenses, known as photochromic, adjust dynamically light intake. We recently evaluated the effect of a new ultra‐responsive light‐adaptive lens on contrast sensitivity recovery during fade back compared to the older photochromic generation, showing that faster fadeback speed improves contrast sensitivity. However, data was lacking in varying light, specifically when moving from bright to dark environments, and in comparison to a static clear lens. This study assessed dynamic contrast sensitivity changes with the new light‐adaptive lens after exposure to a transient bright light, compared to the older photochromic lens and to a static clear lens.

Methods: Ten healthy subjects (28.7 ± 3.4 years, spherical equivalent ‐1.8 ± 1.8 D, astigmatism < 1D) were trained to control contrast of a sinusoidal grating (24 cycles/degree) at 3 m. Three lenses were used in a double‐blind cross‐over design; a clear lens, a photochromic TO2, and a new light‐adaptive TO1, twice as fast as TO2 in returning to clear state. Subjects were exposed to a bright light (8000 lux) for 30 seconds, then transitioned to darkness where contrast sensitivity was measured dynamically for 100 seconds. Recovery times for first contrast perception and 90% contrast sensitivity were recorded for each lens, tested three times. MANOVA with Tukey tests were performed.

Results: TO1 recovered 90% contrast sensitivity 35% faster than clear lens (p < 0.01) and 23% faster than TO2 (p < 0.01). Initial contrast perception recovery was 55% faster with TO1 compared to clear lens (p < 0.001).

Conclusions: The new light‐adaptive lens TO1 significantly improves visual performance in dynamic light conditions compared to the older photochromic lens TO2 and the static clear lens. This performance enhancement reduces light stress and improves visual function under normal viewing conditions.
Retinal vessel flicker light responsitiviness and its relation to analysis protocols, static and metabolic data in healthy subjects
Authors: Artemiev Dmitri , Todorova Margarita
Published: January 2025

Aims/Purpose: To assess agreement between different analysis protocols for determination of retinal vessel dilation response to flicker light (FL) and its relation to static‐ and metabolic parameters of retinal vessels in healthy subjects.

Methods: 24 right eyes of 24 healthy controls (mean age: 35.87 ± SD 14.20 years), who underwent dynamic‐ and static retinal diameter‐ and oxygen saturation measurements on Retinal Vessel Analyser were included (RVA, Imedos, Jena, Germany). Using repeated video analyses, responses to FL were measured within the superior‐temporal (ST) area. Taking the length and the location into account, the FL data were evaluated in 3 groups: length < 1 optic disc (OD) (group 1); length > 1OD: close to the OD (group 2) and within the VesselMap area (group 3).

For comparability, the static‐ (CRA, CRV, AVR) and oxygen saturation parameters (A‐V SO2, V‐SO2, A‐V SO2) were calculated in the ST peripapillary area using the VesselMap tool of RVA and were evaluated in relation to the corresponding dynamic ones (group 3).

Results: In all groups, vascular FL response of arteries was less pronounced compared to venules (p = 0.023). Event thought, FL responses (mean ± SD: FL‐A; FL‐V, %) in group 1 to be more pronounced (mean 3.36 ± 2.31; 4.42 ± 1.69) compared to those in groups 2 (mean: 2.97 ± 2.40; 4.08 ± 1.55) and 3 (2.84 ± 2.29; 4.21 ± 2.03) they did not reach statistically significant values (p > 0.44).

The mean flicker response of venules showed negative correlations to the corresponding static‐ and metabolic parameters: CRV (r = ‐0.489; p = 0.015) and V‐SO2 (r = ‐0.375; p = 0.001).

Conclusions: Our study confirms, that flicker light response, even showing slight difference about its length and location, allows agreeable measurements. However, even in healthy subjects, the effect of the static‐ and metabolic retinal vessel measurements on retinal venular flicker response should be taken in consideration.
Influence of lighting conditions on visual acuity with two intraocular lens designs
Authors: Haddi Inas Baoud Ould , Cervantes Dayan Flores , Ramírez Emilio Dorronzoro , Sánchez Vanesa Blázquez , Arias Cristina Bonnin
Published: January 2025

Purpose: To compare the visual outcomes under different lighting conditions of two intraocular lens designs (Tecnis® Eyhance™ and PhysiOL® IsoPure 123™).

Methods: This was an observational, prospective, cross‐sectional study conducted in accordance with the principles of the Helsinki Declaration. All surgeries were performed by the same experienced surgeon (E.D.R) at Hospital Universitario Sanitas La Moraleja in Madrid. The sample included 40 patients who underwent cataract surgery or lens extraction, with bilateral implantation of one of the three intraocular lenses (IOLs) under study: 20 patients with Eyhance™ IOL and 20 patients with IsoPure 123™ IOL. Patients were evaluated 30 days after surgery. During this visit, binocular visual acuity (VA) was assessed under photopic ( ≥ 85 cd/m2) and mesopic ( ≤ 5 cd/m2) conditions for three distances: distance (4 meters), intermediate (66 cm), and near (40 cm) using a logMAR scale with the ETDRS test. A significance level of p < 0.05 was considered statistically significant.

Results: The analysis of photopic VA did not reveal statistically significant differences for distance vision; the values were (‐0.10 ± 0.08) and (‐0.06 ± 0.07) for Eyhance™, IsoPure 123™ respectively. For intermediate distance, the values were (0.10 ± 0.06) and (0.09 ± 0.08) for Eyhance™ and IsoPure 123™, respectively. Regarding near vision under photopic conditions, the values were (0.07 ± 0.07), (0.07 ± 0.06) for Eyhance™, IsoPure 123™ respectively. In terms of mesopic conditions, no statistically significant differences were found for distance vision, with values of (0.06 ± 0.09) and (0.07 ± 0.08) for Eyhance™ and IsoPure 123™, respectively. For intermediate distance under mesopic conditions, no significant differences were observed, with values of (0.38 ± 0.10) and (0.43 ± 0.11) for Eyhance™ and IsoPure 123™,respectively. For near vision under mesopic conditions, the values were (0.38 ± 0.11) and (0.39 ± 0.11) for Eyhance™ and IsoPure 123™, respectively.

Conclusions: Both Eyhance™ and IsoPure 123™ intraocular lens designs provide similar VA for all distances under both photopic and mesopic lighting conditions. Therefore, both lenses are an excellent option for distance and intermediate vision.