Analysis of Henle's fiber layer and outer retinal layers in cone dystrophy.

PURPOSE: To evaluate Henle's Fiber Layer (HFL) thickness and volume parameters in patients with cone photoreceptor atrophy with directional optical coherence tomography (D-OCT). METHODS: Macular 20°×20° standard and D-OCT images were acquired from patients diagnosed with hereditary cone dystrophy with evident foveal ellipsoid zone defect in OCT, and age-matched healthy controls. Thickness and volume parameters of HFL, outer nuclear layer (ONL) and retinal layers between ellipsoid zone and Bruch membrane complex (EZ-BM) were calculated from manual segmentation through D-OCT images and comparative analysis is performed. RESULTS: Twelve eyes of 6 patients were compared to 12 eyes of 6 age-matched healthy controls (mean age: 29.5±16.6 and 26.6±3.9 years respectively; P=0.162). Patients had lower total HFL volume (0.45±0.03 and 0.85±0.15 mm3; P<0.001) and mean HFL thickness (16.1±1.1 and 30.1±5.3 µm; P<0.001) than healthy controls. Central subfield, parafoveal and perifoveal ETDRS zone HFL parameters in patients were significantly lower than healthy controls. A centrifugal correlation was found between central ONL and the corresponding parafoveal HFL (Spearman's rho: 0.785; P<0.001). CONCLUSION: HFL assessment might be a useful OCT biomarker in patients with cone photoreceptor atrophy. HFL thinning is observed in foveal, parafoveal and perifoveal areas of patients with cone photoreceptor atrophy, while volume reduction in ONL and EZ-BM components were limited to central and parafoveal zones.

A unique and biocompatible corneal collagen crosslinking in vivo.

Corneal crosslinking (CXL) is a widely applied technique to halt the progression of ectatic diseases through increasing the thickness and mechanical stiffness of the cornea. This study investigated the biocompatibility and efficiency of a novel CXL procedure using ruthenium and blue light in rat corneas and evaluated parameters important for clinical application. To perform the CXL procedure, the corneal epithelium of rats was removed under anaesthesia, followed by the application of a solution containing ruthenium and sodium persulfate (SPS). The corneas were then exposed to blue light at 430 nm at 3 mW/cm2 for 5 min. Rat corneas were examined and evaluated for corneal opacity, corneal and limbal neovascularization, and corneal epithelial regeneration on days 0, 1, 3, 6, 8, and 14. On day 28, the corneas were isolated for subsequent tissue follow-up and analysis. CXL with ruthenium and blue light showed rapid epithelial healing, with 100% regeneration of the corneal epithelium and no corneal opacity on day 6. The ruthenium group also exhibited significantly reduced corneal (p < 0.01) and limbal neovascularization (p < 0.001). Histological analysis revealed no signs of cellular damage or apoptosis, which further confirms the biocompatibility and nontoxicity of our method. Confocal and scanning electron microscopy (SEM) images confirmed high density of collagen fibrils, indicating efficient crosslinking and enhanced structural integrity. This study is unique that demonstrates in vivo safety, biocompatibility, and functionality of ruthenium and blue light CXL. This approach can prevent toxicity caused by UV-A light and can be an immediate alternative compared to the existing crosslinking procedures that have side effects and clinical risks for the patients.

Safety, Tolerability, and Short-Term Efficacy of Low-Level Light Therapy for Dry Age-Related Macular Degeneration.

INTRODUCTION: Photobiomodulation (PBM) has become a promising approach for slowing the progression of early and intermediate dry age-related macular degeneration (dAMD) to advanced AMD. This technique uses light to penetrate tissues and activate molecules that influence biochemical reactions and cellular metabolism. This preliminary analysis is aimed at assessing the safety, tolerability, and short-term effectiveness of the EYE-LIGHT®PBM treatment device in patients with dAMD. METHODS: The EYE-LIGHT® device employs two wavelengths, 590 nm (yellow) and 630 nm (red), in both continuous and pulsed modes. Patients over 50 years of age with a diagnosis of dAMD in any AREDS (Age-Related Eye Disease Study) category were randomly assigned to either the treatment group or the sham group. The treatment plan consisted of an initial cycle of two sessions per week for 4 weeks. Safety, tolerability, and compliance outcomes, along with functional and anatomical outcomes, were assessed at the end of the fourth month. RESULTS: This preliminary analysis included data from 76 patients (152 eyes). All patients were fully compliant with treatment sessions, and only one fifth of patients treated with PBM reported mild ocular adverse events, highlighting exceptional results in terms of tolerability and adherence. Changes in best-corrected visual acuity (BCVA) from baseline to month 4 differed significantly between the sham and PBM-treated groups, favoring the latter, with a higher proportion achieving a gain of five or more letters post-treatment (8.9% vs. 20.3%, respectively; p = 0.043). No significant differences in central subfield thickness (CST) were observed between the two groups over the 4-month period. The study also found a statistically significant disparity in mean drusen volume changes from baseline to month 4 between the groups in favor of patients treated with PBM (p = 0.013). CONCLUSION: These preliminary results indicate that PBM treatment using the EYE-LIGHT® system is safe and well tolerated among patients with dAMD. Furthermore, both functional and anatomical data support the treatment's short-term efficacy. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT06046118.

The Relevance of Bacillary Layer Detachment and Choroidal flow Insufficiency in Unilateral Acute Idiopathic Maculopathy Associated with Hand, Foot, and Mouth Disease: A Case Report.

In a case of unilateral acute idiopathic maculopathy (UAIM) following hand, foot, and mouth disease, we aim to discuss the decreased perfusion of choriocapillaris secondary to systemic inflammation as shown by optical coherence tomography angiography (OCTA) and to assess the prognostic significance of bacillary layer detachment (BALAD). A 33-year-old male presented with a decrease of vision in the right eye (OD) for 5 days preceding viral prodromal symptoms and vesicular lesions on bilateral palms and soles along with vesicles and ulcers on the oral mucosa. The best-corrected visual acuity was finger counting at 1 meter distance in OD and 20/20 in his left eye (OS). Dilated fundus examination revealed a circular white-grey dome-shaped elevated lesion at the macula indicative of serous retinal detachment in OD. Spectral-domain optical coherence tomography demonstrated BALAD associated with adjacent subretinal and intraretinal fluid along with pigment epithelium detachment and disruption of ellipsoid and interdigitation zones. OCTA showed decreased choriocapillaris perfusion. All the investigations were normal in OS. The resolution of BALAD occurred during the first 2 days, which was followed by gradual improvement of choriocapillaris flow that lasted 2 months. UAIM is associated with hand, foot, and mouth disease. OCTA demonstrates both qualitative and quantitative data by detecting alterations in the choriocapillaris flow, which could be monitored during the disease course.

Evidence of Mitophagy in Lens Capsule Epithelial Cells of Patients with Pseudoexfoliation Syndrome.

PRCIS: Alterations in the PINK-mediated mitophagy pathway play an important role in PEX disease. PURPOSE: Pseudoexfoliation Syndrome (PEX) is a condition in which aberrant fibrillary protein builds up in various components of the eye and other extraocular tissues. In this study, we aim to investigate the functionality of intracellular auto-degradative machinery -especially mitophagy- and related genes and proteins in PEX. METHODS: Anterior lens capsules were obtained from cataracts patients with and without PEX to constitute the PEX group and age-matched controls during microincision cataracts surgery. PINK1-mediated mitophagy markers were evaluated on the transcriptional and translational level via RT-qPCR and immunohistochemistry analysis, respectively. RESULTS: The lens epithelial cells of PEX patients were characterized by significantly higher PINK1 gene expression compared to that of the controls (P<0.05). In terms of intensity of staining of expressed proteins, PINK1 (P<0.05), Parkin (P<0.01) and LC3B (P<0.01) were all statistically higher in PEX, compared to the controls. CONCLUSION: Altered auto-degradative response -specifically mitophagy- is a component of increased oxidative stress in PEX patients. The role of this mechanism in emerging complications warrants further research.

Capacitive and Efficient Near-Infrared Stimulation of Neurons via an Ultrathin AgBiS2 Nanocrystal Layer.

Colloidal nanocrystals (NCs) exhibit significant potential for photovoltaic bioelectronic interfaces because of their solution processability, tunable energy levels, and inorganic nature, lending them chemical stability. Silver bismuth sulfide (AgBiS2) NCs, free from toxic heavy-metal elements (e.g., Cd, Hg, and Pb), particularly offer an exceptional absorption coefficient exceeding 105 cm-1 in the near-infrared (NIR), surpassing many of their inorganic counterparts. Here, we integrated an ultrathin (24 nm) AgBiS2 NC layer into a water-stable photovoltaic bioelectronic device architecture that showed a high capacitive photocurrent of 2.3 mA·cm-2 in artificial cerebrospinal fluid (aCSF) and ionic charges over 10 µC·cm-2 at a low NIR intensity of 0.5 mW·mm-2. The device without encapsulation showed a halftime of 12.5 years under passive accelerated aging test and did not show any toxicity on neurons. Furthermore, patch-clamp electrophysiology on primary hippocampal neurons under whole-cell configuration revealed that the device elicited neuron firing at intensity levels more than an order of magnitude below the established ocular safety limits. These findings point to the potential of AgBiS2 NCs for photovoltaic retinal prostheses.

A Retina-Inspired Optoelectronic Synapse Using Quantum Dots for Neuromorphic Photostimulation of Neurons.

Neuromorphic electronics, inspired by the functions of neurons, have the potential to enable biomimetic communication with cells. Such systems require operation in aqueous environments, generation of sufficient levels of ionic currents for neurostimulation, and plasticity. However, their implementation requires a combination of separate devices, such as sensors, organic synaptic transistors, and stimulation electrodes. Here, a compact neuromorphic synapse that combines photodetection, memory, and neurostimulation functionalities all-in-one is presented. The artificial photoreception is facilitated by a photovoltaic device based on cell-interfacing InP/ZnS quantum dots, which induces photo-faradaic charge-transfer mediated plasticity. The device sends excitatory post-synaptic currents exhibiting paired-pulse facilitation and post-tetanic potentiation to the hippocampal neurons via the biohybrid synapse. The electrophysiological recordings indicate modulation of the probability of action potential firing due to biomimetic temporal summation of excitatory post-synaptic currents. These results pave the way for the development of novel bioinspired neuroprosthetics and soft robotics, and highlight the potential of quantum dots for achieving versatile neuromorphic functionality in aqueous environments.

A Retina-Inspired Optoelectronic Synapse Using Quantum Dots for Neuromorphic Photostimulation of Neurons.

Neuromorphic electronics, inspired by the functions of neurons, have the potential to enable biomimetic communication with cells. Such systems require operation in aqueous environments, generation of sufficient levels of ionic currents for neurostimulation, and plasticity. However, their implementation requires a combination of separate devices, such as sensors, organic synaptic transistors, and stimulation electrodes. Here, a compact neuromorphic synapse that combines photodetection, memory, and neurostimulation functionalities all-in-one is presented. The artificial photoreception is facilitated by a photovoltaic device based on cell-interfacing InP/ZnS quantum dots, which induces photo-faradaic charge-transfer mediated plasticity. The device sends excitatory post-synaptic currents exhibiting paired-pulse facilitation and post-tetanic potentiation to the hippocampal neurons via the biohybrid synapse. The electrophysiological recordings indicate modulation of the probability of action potential firing due to biomimetic temporal summation of excitatory post-synaptic currents. The results pave the way for the development of novel bioinspired neuroprosthetics and soft robotics and highlight the potential of quantum dots for achieving versatile neuromorphic functionality in aqueous environments.

Fundus topographical distribution patterns of ocular toxoplasmosis.

BACKGROUND: To establish topographic maps and determine fundus distribution patterns of ocular toxoplasmosis (OT) lesions. METHODS: In this retrospective study, patients who presented with OT to ophthalmology clinics from four countries (Argentina, Turkey, UK, USA) were included. Size, shape and location of primary (1°)/recurrent (2°) and active/inactive lesions were converted into a two-dimensional retinal chart by a retinal drawing software. A final contour map of the merged image charts was then created using a custom Matlab programme. Descriptive analyses were performed. RESULTS: 984 lesions in 514 eyes of 464 subjects (53% women) were included. Mean area of all 1° and 2° lesions was 5.96±12.26 and 5.21±12.77 mm2, respectively. For the subset group lesions (eyes with both 1° and 2° lesions), 1° lesions were significantly larger than 2° lesions (5.52±6.04 mm2 vs 4.09±8.90 mm2, p=0.038). Mean distances from foveola to 1° and 2° lesion centres were 6336±4267 and 5763±3491 µm, respectively. The majority of lesions were found in temporal quadrant (p<0.001). Maximum overlap of all lesions was at 278 µm inferotemporal to foveola. CONCLUSION: The 1° lesions were larger than 2° lesions. The 2° lesions were not significantly closer to fovea than 1° lesions. Temporal quadrant and macular region were found to be densely affected underlining the vision threatening nature of the disease.

Case Report: Acute Macular Neuroretinopathy Which Led to COVID-19 Infection Diagnosis.

We present a case of Acute Macular Neuroretinopathy (AMN), which led to the coronavirus disease of 2019 (COVID-19) infection diagnosis. A 27-year-old female patient with flu-like symptoms later proven to be COVID-19 infection presented with acute-onset bilateral gray-like paracentral scotomas. Fundus examination showed a hypopigmented, wedge-like lesion on the superior temporal juxtafoveal area in the right eye, while no significant finding was found in the left eye. Infrared reflectance images demonstrated bilateral hyporeflective lesions in the parafoveal regions of the macula. Spectral-domain optical coherence tomography scans over the corresponding areas detected focal hyperreflectivity in the outer nuclear layer with disruption in the ellipsoid zone and retinal pigment epithelium layers. Based on these findings, the AMN diagnosis was considered. The COVID-19 infection diagnosis was confirmed by a polymerase chain reaction test. COVID-19 disease may cause retinal vascular complications such as AMN. AMN, which shares common viral prodromal symptoms with COVID-19 infection, may be a presenting sign of COVID-19 infection.

Structural and Functional Changes in Non-Paraneoplastic Autoimmune Retinopathy.

BACKGROUND: To describe longitudinal changes in patients with non-paraneoplastic autoimmune retinopathy (npAIR) by utilizing different diagnostic modalities/tests. METHODS: The index study is a retrospective longitudinal review of sixteen eyes of eight patients from a tertiary care eye hospital diagnosed with npAIR. Multiple diagnostic modalities such as wide-angle fundus photography (WAFP), WA fundus autofluorescence (WAFAF), spectral-domain optical coherence tomography (SD-OCT), Goldmann visual field (GVF) perimetry, microperimetry (MP), electrophysiologic testing, and adaptive optics scanning laser ophthalmoscopy (AOSLO) were reviewed and analyzed. RESULTS: At the baseline visits, anomalies were detected by multimodal diagnostic tests on all patients. Subjects were followed up for a median duration of 11.5 [3.0-18.7] months. Structural changes at the baseline were detected in 14 of 16 (87.5%) eyes on WAFP and WAFAF and 13 of 16 (81.2%) eyes on SD-OCT. Eight of the ten (80%) eyes that underwent AOSLO imaging depicted structural changes. Functional changes were detected in 14 of 16 (87.5%) eyes on GVF, 15 of 16 (93.7%) eyes on MP, and 11 of 16 (68.7%) eyes on full-field electroretinogram (ff-ERG). Multifocal electroretinogram (mf-ERG) and visual evoked potential (VEP) tests were performed in 14 eyes, of which 12 (85.7%) and 14 (100%) of the eyes demonstrated functional abnormalities, respectively, at baseline. Compared to all the other structural diagnostic tools, AOSLO had a better ability to demonstrate deterioration in retinal microstructures occurring at follow-ups. Functional deterioration at follow-up was detected on GVF in 8 of 10 (80%) eyes, mf-ERG in 4 of 8 (50%) eyes, and MP in 7 of 16 (43.7%) eyes. The ff-ERG and VEP were stable in the majority of cases at follow-up. CONCLUSIONS: The utilization of multimodal imaging/tests in the diagnosing and monitoring of npAIR patients can aid in identifying anomalous changes over time. Analysis of both the anatomical and functional aspects by these devices can be supportive of detecting the changes early in such patients. AOSLO shows promise as it enables the capture of high-resolution images demonstrating quantifiable changes to retinal microstructure.

Surgical Treatment of Bullous Exudative Retinal Detachment Secondary to Atypical Bilateral Central Serous Chorioretinopathy

This study aimed to report the diagnostic process, treatment, and follow-up of a patient with bullous exudative retinal detachment (RD) associated with an atypical variant of bilateral central serous chorioretinopathy (CSCR). A 28-year-old woman was referred to our clinic for total bullous RD in the right eye with a vision level of light perception only. She had been previously diagnosed with idiopathic uveal effusion syndrome and treated with systemic corticosteroid therapy with no response, and was referred to us for scleral window surgery. Four-quadrant scleral window surgery with external drainage of the subretinal fluid was performed, resulting in a transient partial attachment of the retina. RD started to progress again within 3 weeks, which prompted comprehensive imaging together with more advanced systemic workup for systemic lupus erythematosus and other rheumatological and immunological diseases. Systemic corticosteroid therapy was initiated during this period but did not stop the progression and was discontinued after a short time. Fluorescein angiography and indocyanine green angiography revealed multifocal choroidal leakage foci and large choroidal vessels without any intraocular inflammation findings and led to the diagnosis of atypical CSCR. Pars plana vitrectomy (PPV), internal drainage of the subretinal fluid, endolaser to the focal leakage areas, and intravitreal aflibercept injection were performed. Visual acuity increased to 0.8 within 8 months after the surgery with no recurrence. Bullous exudative RD is a very rare and atypical form of CSCR, and a favorable outcome can be obtained with PPV and surgical drainage of subretinal fluid followed by laser photocoagulation.

MnO2 Nanoflower Integrated Optoelectronic Biointerfaces for Photostimulation of Neurons.

Optoelectronic biointerfaces have gained significant interest for wireless and electrical control of neurons. Three-dimentional (3D) pseudocapacitive nanomaterials with large surface areas and interconnected porous structures have great potential for optoelectronic biointerfaces that can fulfill the requirement of high electrode-electrolyte capacitance to effectively transduce light into stimulating ionic currents. In this study, the integration of 3D manganese dioxide (MnO2 ) nanoflowers into flexible optoelectronic biointerfaces for safe and efficient photostimulation of neurons is demonstrated. MnO2 nanoflowers are grown via chemical bath deposition on the return electrode, which has a MnO2 seed layer deposited via cyclic voltammetry. They facilitate a high interfacial capacitance (larger than 10 mF cm-2 ) and photogenerated charge density (over 20 µC cm-2 ) under low light intensity (1 mW mm-2 ). MnO2 nanoflowers induce safe capacitive currents with reversible Faradaic reactions and do not cause any toxicity on hippocampal neurons in vitro, making them a promising material for biointerfacing with electrogenic cells. Patch-clamp electrophysiology is recorded in the whole-cell configuration of hippocampal neurons, and the optoelectronic biointerfaces trigger repetitive and rapid firing of action potentials in response to light pulse trains. This study points out the potential of electrochemically-deposited 3D pseudocapacitive nanomaterials as a robust building block for optoelectronic control of neurons.

Neutrophil Gelatinase-Associated Lipocalin Level Can Predict Early Organ Damage in Primary Hypertensive Patients: A Pilot Study.

BACKGROUND: Early detection and treatment of complicated arterial hypertension will prevent its effect on the target organs. In line with this purpose, we aimed to reveal the prediction capability of neutrophil gelatinase-associated lipocalin to complicated hypertension. METHODS: In total, 46 patients with hypertension and 21 healthy volunteers were included in the study. Left ventricle morphology and geometry, as systolic and diastolic functions, were analyzed. Global longitudinal strain was measured from recorded apical 3-chamber views. An ophthalmic examination was performed to investigate the presence of retinopathy in individuals with hypertension. In addition, plasma neutrophil gelatinase-associated lipocalin values were evaluated via the method of the enzyme-linked immunosorbent assay. RESULTS: Both neutrophil gelatinase-associated lipocalin levels and global longitudinal strain percentages were statistically significant between the groups with diastolic dysfunction and the groups without diastolic dysfunction. Complicated hypertension was detected in 42 patients. Here, it was found that the neutrophil gelatinase-associated lipocalin level of 144.3 ng/mL predicted complicated hypertension with 0.872 sensitivity and 0.65 specificity values. CONCLUSION: Analyzing neutrophil gelatinase-associated lipocalin levels in patients with hypertension in routine practice can easily and practically detect complicated hypertension patients earlier.

Posterior Segment Ocular Findings in HLA-B27 Positive Patients with Uveitis: A Retrospective Analysis.

Purpose: To describe the prevalence and characteristics of posterior segment manifestations in patients with HLA-B27-associated uveitis using wide field imaging. Methods: Medical records of patients diagnosed with HLA-B27-associated uveitis from a tertiary uveitis clinic were reviewed. Posterior segment involvements including but not limited to peripheral vasculitis, optic disc inflammation, and macula edema documented based on medical records and various imaging modalities including wide field fluorescein angiography and optical coherence tomography, were noted. Demographic characteristics, accompanied with systemic diseases as well as duration and chronicity of uveitis, were also evaluated. Patients with significant systemic and ocular comorbidities were excluded. Statistical analyses including chi-squared tests and paired t-tests were employed. Results: Of the 44 patients with HLA-B27 associated uveitis, 22 patients (50%) were noted to demonstrate posterior segment involvement. Disc leakage and peripheral vasculitis were the most common findings of posterior involvement. Those with anterior chamber inflammation were found to have a significantly increased risk of posterior involvement. Those with posterior involvement were also noted to have a statistically significant decreased visual acuity. No significant association was found between documented duration of disease and posterior segment involvement. Conclusion: The prevalence of posterior segment involvement in HLA-B27 associated uveitis is higher compared to previous reports when evaluated with wide angle imaging modalities. Careful examination of the posterior segment is required in patients with HLA-B27 associated uveitis.

Comparison of pediatric patients with idiopathic uveitis, and uveitis due to juvenile idiopathic arthritis and Behçet's disease.

OBJECTIVES: The aim of this study is to compare the demographic, clinical features, treatment results and outcomes in pediatric patients with idiopathic uveitis and uveitis due to juvenile idiopathic arthritis (JIA) and Behçet's disease (BD). METHODS: 97 pediatric uveitis patients were divided into three groups according to the etiology of uveitis: Group 1 comprised idiopathic uveitis patients, Group 2 uveitis patients who had JIA, and Group 3 uveitis patients with BD. RESULTS: Symptomatic presentation and intermediate uveitis were more common in Group 1 (p < 0.005). Asymptomatic presentation and anterior uveitis in Group 2 (p < 0.005), whereas symptomatic presentation and posterior uveitis in Group 3 (p < 0.005). Erythrocyte sedimentation rate (ESR) was higher in patients with BD or JIA uveitis than those with idiopathic uveitis (p < 0.005). Biologic therapy was more commonly used in JIA group compared to other groups (p < 0.005). Patients who had a complication related with uveitis were more common in females, asymptomatic disease course, and needed use of biologic treatment than in those without any complication (p < 0.005). CONCLUSION: Uveitis accompanying rheumatologic diseases may have asymptomatic and insidious course but have higher ESR as an important notice.

Longitudinal Comparative Analysis of Semi-Automated Aqueous Flare Measurements with Clinical Grading and Visual Outcomes in Uveitic Eyes.

PURPOSE: To evaluate the correlation between longitudinal changes in aqueous flare measured by laser flare photometer (LFP), best-corrected visual acuity (BCVA), and clinical grade using both Standardization of Uveitis Nomenclature (SUN) and modified SUN (MSUN) scales uveitis patients. METHODS: Patients were classified according to both SUN and MSUN grading scales. LFP measurements were acquired (Kowa FM-700) at each visit. Mean change in LFP was assessed longitudinally, comparing with those in visual acuity, SUN, and MSUN grading scales. RESULTS: Mean change in LFP was correlated to those in BCVA (p = .018), SUN scale (p < .001), and MSUN scale (p = .008). Cases within same initial SUN (0 and 1+) and MSUN (0.5+ and 1+) grades and different longitudinal flare prognosis (decreased/unchanged/increased) had significantly different initial LFP values (all p < .05). CONCLUSIONS: LFP measurement is beneficial in monitoring inflammatory activity. Cases of identical clinical flare scores with different clinical prognosis may be predicted by LFP.

Comparison of surgically induced astigmatic changes after cataract surgery in post-Laser in situ keratomileusis corneas versus virgin eyes.

PURPOSE: Postoperative refraction in modern mi-croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK) surgery. The surgically induced astigmatic changes in those eyes may differ not only in magnitude but also in direction compared to virgin corneas. This study aimed to compare the surgically induced astigmatic changes after microscopic cataract surgery between post-LASIK corneas and virgin eyes. METHODS: Cases that underwent microincision cataract surgery in eyes with and without previous LASIK surgery were reviewed. The demographics, the axial length at cataract surgery, the central corneal thickness, spheric and cylindric values, keratometry readings, and postoperative posterior corneal astigmatism were retrospectively evaluated. A modified Alpins method was used for astigmatic vector analysis, and baseline astigmatism, surgically induced astigmatism, difference vector, flattening effect, and torque were assessed. RESULTS: A total of 42 eyes from 24 subjects was evaluated. Group I consisted of 14 eyes with the previous LASIK, and Group II included 28 eyes without any refractive surgery. Preoperative mean central corneal thickness in Group I was significantly thinner (p=0.012). There was no significant difference in baseline astigmatism between the groups regarding magnitude and power vectors. After microincision cataract surgery, there were no significant differences in mean spheric and cylindric values and mean keratometry readings (all p>0.05). However, surgically induced astigmatism and difference vector were significantly higher on J45 vector component in post-LASIK eyes and microincision cataract surgery steepening effect on post-LASIK corneas was significantly higher than those in virgin eyes (p=0.001, p=0.002 and p=0.018, respectively). CONCLUSIONS: Cataract surgery has steepened the corneas in both groups with a significantly higher steepening effect in post-LASIK eyes. Certainly, corneal topography cataract surgery is particularly helpful to provide more precise surgically induced astigmatism interpretations.

Comparison of surgically induced astigmatic changes after cataract surgery in post-Laser in situ keratomileusis corneas versus virgin eyes / Comparação de alterações astigmáticas induzidas cirurgicamente após cirurgia de catarata em córneas ceratomileusis in situ pós-Laser versus olhos virgens

ABSTRACT Purpose: Postoperative refraction in modern mi­croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK) surgery. The surgically induced astigmatic changes in those eyes may differ not only in magnitude but also in direction compared to virgin corneas. This study aimed to compare the surgically induced astigmatic changes after microscopic cataract surgery between post-LASIK corneas and virgin eyes. Methods: Cases that underwent microincision cataract surgery in eyes with and without previous LASIK surgery were reviewed. The demographics, the axial length at cataract surgery, the central corneal thickness, spheric and cylindric values, keratometry readings, and postoperative posterior corneal astigmatism were retrospectively evaluated. A modified Alpins method was used for astigmatic vector analysis, and baseline astigmatism, surgically induced astigmatism, difference vector, flattening effect, and torque were assessed. Results: A total of 42 eyes from 24 subjects was evaluated. Group I consisted of 14 eyes with the previous LASIK, and Group II included 28 eyes without any refractive surgery. Preoperative mean central corneal thickness in Group I was significantly thinner (p=0.012). There was no significant difference in baseline astigmatism between the groups regarding magnitude and power vectors. After microincision cataract surgery, there were no significant differences in mean spheric and cylindric values and mean keratometry readings (all p>0.05). However, surgically induced astigmatism and difference vector were significantly higher on J45 vector component in post-LASIK eyes and microincision cataract surgery steepening effect on post-LASIK corneas was significantly higher than those in virgin eyes (p=0.001, p=0.002 and p=0.018, respectively). Conclusions: Cataract surgery has steepened the corneas in both groups with a significantly higher steepening effect in post-LASIK eyes. Certainly, corneal topography cataract surgery is particularly helpful to provide more precise surgically induced astigmatism interpretations.

RESUMO Objetivo: A refração pós-operatória na cirurgia mo­derna de catarata por microincisão ganha ainda mais importância em pacientes com cirurgia prévia de ceratomileuse in situ assistida por laser (LASIK). As alterações astigmáticas induzidas cirurgicamente nesses olhos podem diferir não apenas em magnitude, mas também em direção em comparação com córneas virgens. O objetivo deste estudo foi comparar as alterações astigmáticas induzidas cirurgicamente após cirurgia de catarata por microincisão entre córneas pós-LASIK e olhos virgens. Métodos: Foi revisada uma série de casos de cirurgia de catarata por microincisão em olhos com e sem cirurgia LASIK anterior. Os dados demográficos, o comprimento axial no momento da cirurgia de catarata, a espessura central da córnea, os valores esféricos e cilíndricos, as leituras da ceratometria e o astigmatismo corneano posterior pós-operatório foram avaliados retrospectivamente. O método Alpins modificado foi usado para análise vetorial astigmática e foram avaliados o astigmatismo basal, o astigmatismo induzido cirurgicamente, o vetor de diferença, o efeito de achatamento e o torque. Resultados: Ao todo, 42 olhos de 24 indivíduos foram avaliados. O Grupo I consistiu em 14 olhos com LASIK prévio; o Grupo II incluiu 28 olhos sem qualquer cirurgia refrativa. A média da espessura corneana central pré-operatória no Grupo I foi significativamente mais fina (p=0,012). Não houve diferença significativa no astigmatismo basal entre os grupos em termos de magnitude e vetores de potência. Após a cirurgia de catarata por microincisão, não houve diferenças significativas nos valores médios esféricos, cilíndricos e leituras médias de ceratometria (todos com p>0,05). No entanto, o astigmatismo induzido cirurgicamente e o vetor de diferença foram significativamente maiores no componente do vetor J45 em olhos pós-LASIK, e o efeito de aumento da inclinação pela cirurgia de catarata por microincisão nas córneas pós-LASIK foi significativo em comparação com olhos virgens (p=0,001, p=0,002 e p=0,018, respectivamente). Conclusões: A cirurgia de catarata aumentou a inclinação das córneas em ambos os grupos, sendo esse aumento significativamente maior nos olhos pós-LASIK. Certamente, a topografia da córnea antes da cirurgia de catarata é particularmente útil para fornecer interpretações mais precisas do astigmatismo induzido cirurgicamente.

The Effect of Anterior Segment Depth on the Accuracy of 7 Different Intraocular Lens Calculation Formulas.

Objectives: To evaluate the effect of anterior segment depth (ASD; sum of anterior chamber depth and lens thickness) on the accuracy of 7 intraocular lens formulas calculated in patients with axial length (AL) between 22.5 and 24.5 mm. Materials and Methods: In this retrospective study, patients who underwent cataract surgery were divided into three groups based on their ASD measurements (Group I: ASD <7.30 mm, Group II: ASD between 7.30-7.90 mm, Group III: ASD >7.90 mm). The mean predictive error (MPE), mean absolute error (MAE), and median absolute error (MedAE) values of each group were compared. The effect of ASD on the predictive error (PE) of each lens formula was additionally tested in subgroups based on mean keratometry (K) values (Subgroup I: K <42.0 D, Subgroup II: K between 42.0-44.5 D, Subgroup III: K >44.5 D). Results: The study included 184 eyes of 184 patients. In Group I, all formulas except Olsen OLCR and Barrett II had clinically myopic MPEs. In Group II, the MPEs of all lens formulas except Barrett II were statistically non-different from zero (p>0.05). In Group III, the MPEs of all lens formulas were found to be statistically hyperopic. In Group III, all formulas except Olsen OLCR were significantly shifted to more hyperopic results when compared with Groups I and II (p<0.05). ASD was positively correlated with the PEs of the SRK/T, Holladay I, Hoffer Q, Barrett II, Hill-RBF, and Haigis formulas. In cases with mean K greater than 42.0 D, ASD was similarly correlated with PE for all formulas except Olsen OLCR. Conclusion: In eyes with AL between 22.5 and 24.5 mm, the predictions of lens formulas were significantly hyperopic in cases with greater ASD.