Evaluating keratometry and corneal astigmatism data from biometers and anterior segment tomographers and mapping to reconstructed corneal astigmatism.

BACKGROUND: To compare results from different corneal astigmatism measurement instruments; to reconstruct corneal astigmatism from the postimplantation spectacle refraction and toric intraocular lens (IOL) power; and to derive models for mapping measured corneal astigmatism to reconstructed corneal astigmatism. METHODS: Retrospective single centre study involving 150 eyes treated with a toric IOL (Alcon SN6AT, DFT or TFNT). Measurements included IOLMaster 700 keratometry (IOLMK) and total keratometry (IOLMTK), Pentacam keratometry (PK) and total corneal refractive power in 3 and 4 mm zones (PTCRP3 and PTCRP4), and Aladdin keratometry (AK). Regression-based models mapping the measured C0 and C45 components (Alpin's method) to reconstructed corneal astigmatism were derived. RESULTS: Mean C0 components were 0.50/0.59/0.51 dioptres (D) for IOLMK/PK/AK; 0.2/0.26/0.31 D for IOLMTK/PTCRP3/PTCRP4; and 0.26 D for reconstructed corneal astigmatism. All corresponding C45 components ranged around 0. The prediction models had main diagonal elements lower than 1 with some crosstalk between C0 and C45 (nonzero off-diagonal elements). Root-mean-squared residuals were 0.44/0.45/0.48/0.51/0.50/0.47 D for IOLMK/IOLMTK/PK/PTCRP3/PTCRP4/AK. CONCLUSIONS: Results from the different modalities are not consistent. On average IOLMTK/PTCRP3/PTCRP4 match reconstructed corneal astigmatism, whereas IOLMK/PK/AK show systematic C0 offsets of around 0.25 D. IOLMTK/PTCRP3/PTCRP4. Prediction models can reduce but not fully eliminate residual astigmatism after toric IOL implantation.

Meridional analysis for calculation of the toric power of phakic IOLs.

PURPOSE: To present a reproducible method to calculate the toricity needed at the intraocular lens (IOL) plane with toric phakic IOLs (ICL, Staar Surgical) and compare its results with those obtained with the online calculator provided by the manufacturer. DESIGN: Retrospective case series. SETTING: Private practice, Buenos Aires, Argentina. METHODS: The formula originally described by Holladay to calculate the IOL power in phakic eyes was used to calculate the required spherical power along the less refractive meridian and along the more refractive meridian. Meridional analysis was applied to calculate the required toricity at the IOL plane and the surgically induced corneal astigmatism was incorporated into the calculations. The refractive cylinder predicted by this method and by the online calculator of the manufacturer were compared to the postoperative refractive cylinder by means of vector analysis. The possible changes in the ratio of toricity in patients with different amounts of astigmatism and anterior chamber depth are assessed in a theoretical section. RESULTS: In 35 eyes, the measured mean postoperative refractive cylinder was 0.09 D @ 99°, the mean predicted postoperative refractive astigmatism was 0.04 D @ 102° according to the manufacturer's online calculator and 0.09 D @100° according to our method. With both methods, 91.43% of eyes had an absolute cylinder prediction error within ±0.50 diopters. CONCLUSIONS: The method described in this article to calculate the toricity of phakic IOLs has a refractive accuracy similar to that of the original calculator developed by the manufacturer.

Differences Between Simulated Keratometry and Total Corneal Power in Eyes With Keratoconus and a Formula to Improve IOL Power Calculation Results.

PURPOSE: To compare simulated keratometry (SimK) and total corneal power (TCP) in keratoconic eyes, to determine whether the differences are systematic and predictable and to evaluate an adjusted TCP-based formula for intraocular lens (IOL) power calculation. METHODS: In a consecutive series of keratoconic eyes, measurements of SimK, TCP, posterior keratometry, and anterior and posterior corneal asphericities (Q-values) were retrospectively collected. The difference between SimK and TCP was linearly correlated to the biometric parameters. In a separate sample of keratoconic eyes that had undergone cataract surgery, IOL power was calculated with the Barrett Universal II, Hoffer QST, Holladay 1, Kane, and SRK/T formulas using the SimK and an adjusted TCP power. The respective prediction errors were calculated. RESULTS: A total of 382 keratoconic eyes (271 patients) were enrolled. An increasing overestimation of SimK by TCP was detected from stage I to III, with a significant correlation between the SimK and TCP difference and SimK in the whole sample (P < .0001, r2 = 0.1322). Approximately 7% of cases presented an underestimation of SimK by TCP. IOL power calculation with the adjusted TCP improved outcomes, achieving a maximum of 80% of eyes with a prediction error within ±0.50 diopters with the Hoffer QST, Holladay 1, and Kane formulas. CONCLUSIONS: Overall, SimK overestimated TCP. Such a difference could not be predicted by any variable. The proposed TCP-adjustment formula (TCPadj = TCP + 0.56 diopters) in keratoconic eyes for IOL power calculation might be valuable for improving refractive outcomes. [J Refract Surg. 2024;40(4):e253-e259.].

Sectorial Ganglion Cell Complex Thickness as Biomarker of Vision Outcome in Patients With Dominant Optic Atrophy.

Purpose: Dominant optic atrophy (DOA) is an inherited condition caused by autosomal dominant mutations involving the OPA-1 gene. The aim of this study was to assess the relationship between macular ganglion cell and inner plexiform layer (GC-IPL) thickness obtained from structural optical coherence tomography (OCT) and visual outcomes in DOA patients. Methods: The study recruited 33 patients with confirmed OPA-1 heterozygous mutation and DOA. OCT scans were conducted to measure the GC-IPL thickness. The average and sectorial Early Treatment Diabetic Retinopathy Study (ETDRS) charts (six-sector macular analysis to enhance the topographical analysis) centered on the fovea were considered. Several regression analyses were carried out to investigate the associations between OCT metrics and final best-corrected visual acuity (BCVA) as the dependent variable. Results: The mean BCVA was 0.43 ± 0.37 logMAR, and the average macular GC-IPL thickness was 43.65 ± 12.56 µm. All of the GC-IPL sectors were significantly reduced and correlated with BCVA. The univariate linear regression and the multivariate stepwise regression modeling showed that the strongest association with final BCVA was observed with the internal superior GC-IPL thickness. Dividing patients based on BCVA, we found a specific pattern. Specifically, in patients with BCVA ≤ 0.3 logMAR, the external superior and inferior sectors together with the internal superior were more significant; whereas, for BCVA > 0.3 logMAR, the external superior sector and internal superior sector were more significant. Conclusions: The study identified OCT biomarkers associated with visual outcomes in DOA patients. Moreover, we assessed a specific OCT biomarker for DOA progression, ranging from patients in the early stages of disease with more preserved GC-IPL sectorial thickness to advanced stages with severe thinning.

Peripapillary hyperreflective ovoid mass-like structures (PHOMS) in patients with acute Leber's hereditary optic neuropathy.

PURPOSE: Peripapillary hyperreflective ovoid mass-like structures (PHOMS) represent an optical coherence tomography (OCT) finding that has been characterized in different forms of pseudopapilledema. The aim of this study was to investigate the prevalence of PHOMS in patients affected by acute LHON using structural OCT, and to provide a detailed description of these findings. METHODS: Patients with a clinical and molecularly confirmed diagnosis of acute LHON (visual loss having occurred less than 6 months) were enrolled from the neuro-ophthalmology clinic at San Raffaele Scientific Institute. Patients had a complete ophthalmologic evaluation, including imaging with structural OCT. RESULTS: Our analysis included 16 patients (21 eyes-8 males and 8 females) with acute LHON. Structural OCT exhibited PHOMS in 12 eyes from 9 patients with a prevalence rate of 57.1%. In a subsequent topographical assessment in the peripapillary area, the most common location of PHOMS was the temporal region (12 out of 12 eyes), while the nasal region was affected in 2 eyes (16.7%). Considering the 12 eyes with PHOMS, mean ± SD temporal peripapillary RNFL thickness was 87.5 ± 28.4 microns. The temporal peripapillary RNFL thickness was significantly lower in eyes without PHOMS (63.7 ± 32.2 microns; P = 0.40). At the 12-month follow-up visit, PHOMS disappeared in 10 out of 12 eyes. CONCLUSIONS: Acute LHON eyes have PHOMS which are mainly confined to the temporal peripapillary sector. PHOMS may represent swelled retinal fibers that have herniated or are in stasis.

Non-Lethal Detection of Ranavirus in Fish.

Emergent infectious diseases have an increasing impact on both farmed animals and wildlife. The ability to screen for pathogens is critical for understanding host-pathogen dynamics and informing better management. Ranavirus is a pathogen of concern, associated with disease outbreaks worldwide, affecting a broad range of fish, amphibian, and reptile hosts, but research has been limited. The traditional screening of internal tissues, such as the liver, has been regarded as the most effective for detecting and quantifying Ranavirus. However, such methodology imposes several limitations from ethical and conservation standpoints. Non-lethal sampling methods of viral detection were explored by comparing the efficacy of both buccal swabbing and fin clipping. The study was conducted on two Iberian, threatened freshwater fish (Iberochondrostoma lusitanicum and Cobitis paludica), and all samples were screened using qPCR. While for C. paludica both methods were reliable in detecting Ranavirus, on I. lusitanicum, there was a significantly higher detection rate in buccal swabs than in fin tissue. This study, therefore, reports that fin clipping may yield false Ranavirus negatives when in small-bodied freshwater fish. Overall, buccal swabbing is found to be good as an alternative to more invasive procedures, which is of extreme relevance, particularly when dealing with a threatened species.

Development of colorimetric sensors based on gold nanoparticles for SARS-CoV-2 RdRp, E and S genes detection.

We present a fast, reliable and easy to scale-up colorimetric sensor based on gold nanoparticles (AuNPs) to detect the sequences coding for the RdRp, E, and S proteins of SARS-CoV-2. The optimization of the system (so-called "the sensor") includes the evaluation of different sizes of nanoparticles, sequences of oligonucleotides and buffers. It is stable for months without any noticeable decrease in its activity, allowing the detection of SARS-CoV-2 sequences by the naked eye in 15 min. The efficiency and selectivity of detection, in terms of significative colorimetric changes in the solution upon target recognition, are qualitatively (visually) and quantitatively (absorbance measurements) assessed using synthetic samples and samples derived from infected cells and patients. Furthermore, an easy and affordable amplification approach is implemented to increase the system's sensitivity for detecting high and medium viral loads (≥103 - 104 viral RNA copies/µl) in patient samples. The whole process (amplification and detection) takes 2.5 h. Due to the ease of use, stability and minimum equipment requirements, the proposed approach can be a valuable tool for the detection of SARS-CoV-2 at facilities with limited resources.

Intraocular lens power calculation with ray tracing based on AS-OCT and adjusted axial length after myopic excimer laser surgery.

PURPOSE: To report the results of intraocular lens (IOL) power calculation by ray tracing in eyes with previous myopic excimer laser surgery. SETTING: G.B. Bietti Foundation I.R.C.C.S., Rome, Italy. DESIGN: Retrospective interventional case series. METHODS: A series of consecutive patients undergoing phacoemulsification and IOL implantation after myopic excimer laser was investigated. IOL power was calculated using ray-tracing software available on the anterior segment optical coherence tomographer MS-39. Axial length (AL) was measured by optical biometry, and 4 values were investigated: (1) that from the printout, (2) the modified Wang/Koch formula, and (3) the polynomial equation for the Holladay 1 and (4) for the Holladay 2 formulas. The mean prediction error (PE), median absolute error (MedAE), and percentage of eyes with a PE within ±0.50 diopters (D) were reported. RESULTS: The study enrolled 39 eyes. Entering the original AL into ray tracing led to a mean hyperopic PE (+0.56 ±0.54 D), whereas with the Wang/Koch formula, a mean myopic PE (-0.41 ±0.53 D) was obtained. The Holladay 1 and 2 polynomial equations lead to the lowest PEs (-0.10 ±0.49 D and +0.08 ±0.49 D, respectively), lowest MedAE (0.37 D and 0.25 D), and highest percentages of eyes with a PE within ±0.50 D (71.79% and 76.92%). Calculations based on the Holladay 2 polynomial equation showed a statistically significant difference compared with other methods used (including Barrett-True K formula), with the only exception of the Holladay 1 polynomial equation. CONCLUSIONS: IOL power was accurately calculated by ray tracing with adjusted AL according to the Holladay 2 polynomial equation.

Characterization of the sensitization profile of bee venom allergic patients ­ Association with the severity of reaction? / Caracterização do perfil de sensibilização molecular de doentes alérgicos à picada de abelha - Associação com a gravidade da reação?

Introduction: Bee venom (BV) allergy, a common cause of anaphylaxis in adults, is often associated with severe reactions. The use of component-resolved diagnostics (CRD) increases diagnostic accuracy. Objectives: To characterize the sensitization profile of BV allergic patients and a possible correlation with the severity of reaction. Materials and methods: We selected patients with a clinical history of BV allergy, positive skin tests, and specific IgE (sIgE) for BV. The allergenic profile was analyzed by both CRD and Western blot using a well-defined and properly characterized BV extract. Results: Forty-four patients were included, 30 (68.2%) were men. Mean age was 48.9 (SD 17.9) years. Eleven (25%) had large local reactions (LLRs) and 33 (75%) had systemic sting reactions (SSRs). One patient with negative sIgE for BV had positive sIgE for Api m 1, Api m 5, and Api m 10. The sensitization frequency for BV, Api m 1, Api m 2, Api m 3, Api m 5, and Api m 10 was 97.7%, 75%, 47.7%, 20.5%, 40.9%, and 61.4%, respectively. Five patients (11.4%) were sensitized to all BV components. CRD association showed that 5 patients (11.4%) were sensitized only to Api m 1, 8 (18.2%) to Api m 1/Api m 3/Api m 10, and 16 (36.6%) to Api m 1/ Api m 10. Twenty-eight patients (84.8%) with SSRs were sensitized to Api m 1, and concomitant sensitization to Api m 1/Api m 10 was detected in 20 (60.6%). There was a significant difference in Api m 1 between patients with LLRs and SSRs (p = 0.0104). Similar profiles were identified by Western blot analysis, with relevance for the detection of Api m 6 in 28 (64%) and Api m 4 in 16 (36%) patients. Conclusion: The analysis of the sensitization profile using CRD and the association of several of these components can increase diagnostic accuracy in BV allergy. Our data showed that concomitant sensitization to Api m 1 and Api m 10, detected by both CRD and electrophoretic profile, may be associated with SSRs. We emphasize the identification of sensitization to Api m 6 in > 50% of patients, which may be considered a major allergen, and to Api m 4, which may be related to reactions during BV immunotherapy.

Introdução: A alergia ao veneno de abelha (VA) é uma causa frequente de anafilaxia em adultos e está muitas vezes associada a reações graves. O diagnóstico por componentes moleculares (CRD) contribui para uma melhor caracterização desta alergia. Objetivos: Caracterização do perfil de sensibilização molecular de doentes alérgicos ao veneno de abelha e possível correlação com a gravidade da reação. Material e métodos: Selecionaram-se doentes com história de alergia a VA, testes cutâneos e IgE específica (sIgE) positivos para VA. Avaliou-se o perfil alergênico por CRD e por Western Blot, utilizando extrato de VA bem caracterizado. Resultados: 44 doentes, 30 (68,2%) sexo masculino. Média de idades 48,9 ± 17,9 anos, 11 (25%) com reacções locais exuberantes e 33 (75%) com reações sistêmicas à picada (SSR). Um doente tinha sIgE negativa para VA, mas Api m 1, Api m 5 e Api m 10 positivas. A frequência de sensibilização para VA, Api m 1, Api m 2, Api m 3, Api m 5 e Api m 10 foi 97,7%; 75%; 47,7%; 20,5%; 40,9% e 61,4%, respectivamente. Cinco (11,4%) doentes estavam sensibilizados a todos os componentes. Por associação de CRD, detectaram-se 5 (11,4%) doentes sensibilizados apenas a Api m 1, 8 (18,2%) a Api m 1/Api m 3/Api m 10, e 16 (36,6%) a Api m 1/Api m 10. Vinte e oito (84,8%) doentes com SSR tinham Api m 1 positiva e 20 (60,6%) tinham Api m 1/Api m 10 simultaneamente positivas. Observou-se uma diferença estatisticamente significativa para a Api m 1 entre doentes com reações locais exuberantes e sistêmicas (p = 0,0104). Os perfis detectados por Western Blot foram semelhantes, de referir, à detecção de Api m 6 em 28 (64%) e Api m 4 em 16 (36%) dos doentes. Conclusão: A análise do perfil de sensibilização através de CRD e a sua associação aumentam a precisão do diagnóstico de alergia a VA. Sensibilização simultânea a Api m 1 e Api m 10 identificados tanto por CRD como por perfil eletroforético, pode estar associada à ocorrência de SSR. Destaca-se a sensibilização a Api m 6 em > 50% dos doentes, podendo ser considerado um alergênio major, e a Api m 4, possivelmente associado a reações durante a imunoterapia com VA.

Kounis syndrome - Report of 4 cases / Síndrome de Kounis - Relato de 4 casos

Kounis syndrome is described as the occurrence of myocardial injury following a hypersensitivity reaction triggered by allergen exposure. The actual incidence is unknown, as most of the information comes from case reports and there are no international recommendations. Kounis syndrome does not seem to be rare but rather underdiagnosed. We report and discuss the clinical presentation and management of 4 cases of Kounis syndrome. All patients presented with anaphylaxis and chest pain. Patient age ranged from 44 to 83 years. Anaphylaxis triggers were nonsteroidal anti-inflammatory drugs and antibiotics. It is important to recognize Kounis syndrome in order to conduct an adequate investigation and prevent further events. A major difficulty is that the treatment of the 2 entities (hypersensitivity reaction and acute coronary syndrome) may worsen each other. Large prospective studies are needed to establish definitive treatment guidelines for these patients.

A síndrome de Kounis caracteriza-se pela ocorrência de uma síndrome coronária aguda no contexto de uma reação alérgica concomitante desencadeada por exposição a um alergênio. A sua incidência real é desconhecida e não há consenso relativamente à abordagem, uma vez que a maioria dos dados provem de relatos de casos. A síndrome de Kounis não parece ser uma entidade rara, mas é infrequentemente diagnosticada. Apresentamos quatro casos, a sua apresentação clínica e abordagem diagnóstica e terapêutica. Todos os doentes, com idades entre os 44 e os 83 anos, se apresentaram com anafilaxia e dor torácica. Os fatores desencadeantes foram fármacos: anti-inflamatórios não esteroides e antibióticos. Torna-se importante reconhecer a síndrome de Kounis, de modo a que possa ser feita investigação adequada e prevenidos novos eventos. A grande dificuldade reside no fato de que o tratamento das duas entidades (Reação de hipersensibilidade e Síndrome coronária aguda), pode agravar uma à outra. São necessários estudos prospetivos alargados de modo a estabelecer diretrizes definitivas para o tratamento destes doentes.

MicroRNA sensors based on gold nanoparticles.

MicroRNAs (miRNAs) are small regulatory RNAs, the dysregulation of which has been associated with the progression of several human diseases, including cancer. Interestingly, these molecules can be used as biomarkers for early disease diagnosis and can be found in a variety of body fluids and tissue samples. However, their specific properties and very low concentrations make their detection rather challenging. In this regard, current detection methods are complex, cost-ineffective, and of limited application in point-of-care settings or resource-limited facilities. Recently, nanotechnology-based approaches have emerged as promising alternatives to conventional miRNA detection methods and paved the way for research towards sensitive, fast, and low-cost detection systems. In particular, due to their exceptional properties, the use of gold nanoparticles (AuNPs) has significantly improved the performance of miRNA biosensors. This review discusses the application of AuNPs in different miRNA sensor modalities, commenting on recently reported examples. A practical overview of each modality is provided, highlighting their future use in clinical diagnosis. Graphical abstract ᅟ.

Targeted microbicides for preventing sexual HIV transmission.

Sexual transmission remains one of the most significant hurdles in the fight against HIV infection. The use of vaginal or rectal microbicides has been proposed for topical pre-exposure prophylaxis but available results from clinical trials of candidate products have been, at best, less than optimal. While waiting for the first product to get regulatory approval, novel approaches are being explored in order to enhance efficacy, as well as to assure safety. Strategies involving specific delivery of antiviral agents to key players involved in the early steps of sexual transmission have the potential to help achieving such purposes. Engineering systems that allow targeting cells, tissues or other biological structures of interest may provide a way to modulate local pharmacokinetics of promising microbicide molecules and, thus, maximize protection. This concise review discusses the identification and use of potential targets for such purpose, while detailing on several examples of targeted systems engineered as potential microbicide candidates. Furthermore, remaining challenges and hints for future work in the field of targeted microbicides are addressed.

Design of a Water Soluble Fluorescent 3-Hydroxy-4-Pyridinone Ligand Active at Physiological pH Values.

In the present work we report the structure and the spectroscopic characterization of a new fluorescent 3-hydroxy-4-pyridinone ligand D-3,4-HPO. The synthesis of the compound was performed in two steps, which involve the reaction of the commercially available fluorophore dansyl chloride with a 3-hydroxy-4-pyridinone chelating unit and further deprotection. The new fluorescent chelator was characterized in the solid state by single-crystal X-ray diffraction and in solution by NMR, MS, absorption and fluorescence spectroscopies. The analysis of the variation of the absorption spectrum with pH allowed the determination of four pK a values (pK a1  = 3.50, pK a2  = 4.50, pK a3  = 9.60, pK a4  = 10.20) and establishment of the corresponding distribution diagram. The study of the fluorescence properties of the ligand show that in the pH range between 4 and 9 the fluorescence intensity is constant and has its maximum value thus allowing its further use at physiological pH values. The interaction of the ligand with copper(II) was accessed by fluorescence spectroscopy in MOPS buffer and the results show that the presence of copper(II) quenches the fluorescence of the ligand in ca 94 % at a ligand: metal ratio of 2:1. The latter result is consistent with the formation of a copper(II) complex with the bidentate ligand, as confirmed by the EPR spectroscopy. Graphical Abstract New water soluble fluorescent ligand active at physiological pH values.