New disposable esthesiometer (KeraSenseⓇ) to improve diagnosis and management of neurotrophic keratitis.

PURPOSE: To validate the use, repeatability, and reproducibility of a new, cost-effective, disposable, sterile device (KeraSenseⓇ, Dompè farmaceutici SpA, Milan Italy) compared to Cochet-Bonnet (CB) esthesiometer. Secondly, to identify a simple, safe, rapid, and low-cost test to diagnose neurotrophic keratitis (NK). METHODS: 16 patients with diagnosis of NK stage I, 25 patients with diabetes mellitus (DM), and 26 healthy subjects were included in the study. Corneal sensitivity (CS) was assessed by CB and KeraSenseⓇ. Repeatability, accuracy, and reproducibility of the novel disposable aesthesiometer were assessed. Specificity, sensitivity, and cut-off value for NK diagnosis were calculated by ROC curve analysis. RESULTS: All NK patients showed a CS ≤ 40 mm, while none of the healthy patients showed a CS value < 50 mm. Significant agreement was found between CB measurements and the single use esthesiometer evaluations of CS (p < 0.001). Repeatability evaluations of the single use esthesiometer showed 100% agreement between different measurements (p < 0.001). Reproducibility evaluations showed 99.6% concordance between different operators (p < 0.001). A 55 mm value of the single use esthesiometer was adequate to exclude an NK diagnosis, while all NK patients showed a value ≤ 35 mm. CONCLUSIONS: Corneal hypo/anaesthesia is considered the hallmark of NK. The use of the novel single-use esthesiometer will allow for a diagnostic improvement in NK, sparing time and guaranteeing patients' safety. Diabetic patients despite normal corneal findings may show impairment of CS, suggesting a preclinical stage of NK, requiring a close follow-up.

Pupil size measurements with a multifunctional aberrometer/coherence interferometer/tomographer and two infrared-based pupillometers.

PURPOSE: To compare precision of pupil size measurements of a multifunctional device (Pentacam AXL Wave [Pentacam]) and 2 infrared-based pupillometers (PupilX, Colvard) and to compare repeatability of Pentacam and PupilX. SETTING: Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany. DESIGN: Prospective, comparative trial. METHODS: Pupil diameter of healthy eyes was measured with Colvard once and Pentacam without glare (WO) and with glare (WG), PupilX in 0, 1, and 16 lux 3 times each. In a second series, measurements with Pentacam WO and PupilX in 0.06 and 0.12 lux were assessed. RESULTS: 36 eyes of participants aged 21 to 63 years were included. Mean pupil diameter was 6.05 mm with Colvard, 5.79 mm (first series), 5.50 mm (second series) with Pentacam WO, 3.42 mm WG, 7.26 mm PupilX in 0, 4.67 mm 1, 3.66 mm 16, 6.82 mm in 0.06, and 6.39 mm in 0.12 lux. Measurements with Pentacam WO were significantly different to PupilX in 0, 0.06, 0.12, and 1 lux (all P < .001), but not to Colvard ( P = .086). Pupil size measured with Pentacam WG and PupilX in 16 lux was not significantly different ( P = .647). Consecutive measurements with Pentacam WO and WG had mean SD of 0.23 mm and 0.20 mm, respectively, and with PupilX 0.11 in 0, 0.24 mm 1, and 0.20 mm in 16 lux. CONCLUSIONS: Pentacam provided good assessment of pupil size but was not equivalent to PupilX in low lighting conditions. Repeatability was more favorable for Pentacam.

Corneal biomechanics and glaucoma beyond the bidirectional impact of intraocular pressure and corneal deformation response / Biomecânica corneana e glaucoma além do impacto bididirecional da pressão intraocular e da resposta da deformação corneana

ABSTRACT The purpose of this study was to highlight the impact of biomechanical corneal response in available in vivo tonometry methods for glaucoma management. Systematic review of non-contact air-puff tonometers that analyzes the corneal deformation response, with special focus on the investigation of the correlation of derived parameters with intraocular pressure measurements. The two actual and commercially available in vivo corneal tonometers provide promising information about biomechanical characteristics of the cornea and its relation to glaucoma, allowing the development of new protocols to evaluate, diagnose, and manage this disease.

RESUMO O objetivo deste estudo é destacar o impacto da resposta biomecânica corneana em métodos de tonometria in vivo disponíveis para o manejo do glaucoma. Trata-se de revisão sistemática de tonômetros de ar que analisa a resposta à deformação corneana, com foco especial na investigação da correlação dos parâmetros derivados com as medições da pressão intraocular. Os dois tonômetros mais recentes e comercialmente disponíveis fornecem informações promissoras sobre as características biomecânicas da córnea e sua relação com o glaucoma, permitindo o desenvolvimento de novos protocolos para avaliar, diagnosticar e controlar a doença.

Handheld fundus camera performance, image quality and outcomes of diabetic retinopathy grading in a pilot screening study.

PURPOSE: To compare the performance and image quality of the handheld fundus camera to standard table-top fundus cameras in diabetic retinopathy (DR) screening. The reliability and diagnostic accuracy of DR grading performed by an ophthalmologist and a photographer reader were evaluated. MATERIALS AND METHODS: 157 patients with diabetes, attending screening or follow-up of DR, were evaluated by fundus photographs taken in mydriasis by Optomed Aurora and Canon or Zeiss Visucam fundus cameras. The image quality and the severity of DR were evaluated independently by an ophthalmologist and experienced photographer. The sensitivity, specificity and reliability of the assessments were determined. RESULTS: 1884 fundus images from 314 eyes were analysed. In 53% of all eyes, DR was not present. 10% had mild non-proliferative diabetic retinopathy (NPDR), 16% moderate NPDR, 6% severe NPDR and 16% proliferative diabetic retinopathy (PDR). The DR grading outcomes by Aurora highly equalled to those of Canon or Zeiss (κ = 0.93, 95% CI 0.91 to 0.94), and there was almost perfect agreement in grading between the ophthalmologist and photographer (κ = 0.96, 95% CI 0.95 to 0.97). The image quality of Aurora was sufficient for reliable assessment according to both graders in 84-88% of the cases. CONCLUSION: The Optomed Aurora fundus camera seems appropriate for DR screening. The sufficient image quality and high diagnostic accuracy for DR grading are supportive for a less expensive and easily transportable screening system for DR. Immediate image grading carried out by a photographer would further improve and speed up the screening process in all settings.

Bulbar Redness and Dry Eye Disease: Comparison of a Validated Subjective Grading Scale and an Objective Automated Method.

SIGNIFICANCE: In this study, assessments of conjunctival redness were performed to evaluate whether patients with or without dry eye disease (DED) could be discriminated based on this measure. Our findings suggest that subjectively grading redness by quadrant, as opposed to automated en face measurements, may be more suitable for this purpose. PURPOSE: This study aimed to quantify bulbar redness using the validated bulbar redness (VBR) grading scale and an automated objective method (Oculus Keratograph 5M; K5M) in participants with DED and non-DED controls. METHODS: Participants with DED (Ocular Surface Disease Index score ≥20 and Oxford scale corneal staining ≥2) and controls (Ocular Surface Disease Index score ≤10 and corneal staining ≤1) attended two study visits. In part 1A of visit 1, baseline bulbar redness was graded with the VBR scale in each conjunctival quadrant of both eyes, followed by automated measurements of temporal and nasal redness with the K5M. This was immediately followed by part 1B, during which a topical vasoconstrictor was instilled into both eyes. Redness assessments were repeated 5 and 30 minutes after instillation with both instruments. Participants returned 14 days later for visit 2, where the same assessments as for visit 1A were repeated. RESULTS: Seventy-four participants (50 DED and 24 controls) completed the study. There were statistically significant differences in redness between the DED and control groups when assessed with the VBR scale (14/16 comparisons; all, P < .05), whereas no significant differences in K5M-derived redness between the DED and non-DED groups were found at any location or time point. Both subjective and objective instruments detected statistically significant reductions in redness 5 and 30 minutes after instillation of the vasoconstrictor (all, P < .01). CONCLUSIONS: Although both subjective and objective instruments were sensitive to detecting changes in redness induced by vasoconstriction, statistically significant differences in redness between DED and control groups were only found using the VBR scale.

Influence of Artificial Tears on Keratometric Measurements in Cataract Patients.

PURPOSE: To assess the influence of artificial tears of different viscosity on K-readings prior to cataract surgery. DESIGN: Prospective randomized crossover, before-and-after clinical study. METHODS: Setting: Department of Ophthalmology, Medical University of Vienna. PATIENT POPULATION: A total of 123 eyes of 80 patients prior to cataract surgery were assigned to 2 groups based on normal and dry eyes. INTERVENTION: Two native baseline keratometries were followed by instillation of either high- or low-viscosity eye drops. Keratometry was repeated 30 seconds, 2 minutes, and 5 minutes after instillation. MAIN OUTCOME MEASURES: Influence of eye drops of different viscosity in normal and dry eyes on short time K-readings. RESULTS: Repeatability between native baseline measurements was high (standard deviation = 0.02 mm in normal and in dry eyes). In normal and dry eyes, a statistically significant increase in measurement variability after instillation of both low-viscosity and high-viscosity eye drops was observed (P < .01). Measurement variability was most pronounced between baseline measurement and 30 seconds and diminished over time. Variability of K-readings appeared higher in dry eyes compared with normal eyes. Astigmatism changed more than 0.5 diopters in 13.2% of normal eyes and 34.4% in dry eyes using eye drops of high viscosity. CONCLUSION: Tear film-stabilizing eye drops prior to keratometry measurements influenced K-readings significantly, especially in dry eyes. A time period of more than 5 minutes should be allowed to pass after instillation of eye drops. The higher the viscosity of the eye drops, the stronger the influence and the longer its persistence.

Red reflex technique training simulator in newborns / Simulador para o treinamento da técnica do reflexo vermelho em recém-nascidos

Abstract: Introduction: The Red Reflex Test (RRT) consists of visualizing the reflection that light causes in the retina when it passes through the pupil. It is a screening test for pathologies that can lead to blindness, which still have great social and economic impact on families and the government. Teaching through simulators allows students and health professionals to acquire and improve their clinical skills. Objective: The aim of the study is to develop a low-cost dummy, 3D printed and based on the Arduino platform, for the training of the red reflex technique (RRT) in newborns and evaluate its educational effectiveness. Method: A RRT dummy was presented to 7 expert judges: 6 pediatricians and 1 ophthalmologist to evaluate its applicability in medical learning. For this purpose, they used a 14-item Likert scale of 5 points. Subsequently, 40 individuals participated in a course: 33 medical students, 5 pediatric residents, a nurse and a general physician. The participants were randomly assigned to two groups: control (CG) and experimental (EG) group. Each group consisted of 20 participants. The EG went through 4 stages: 1) theoretical background; 2) handling of the simulator; 3) simulated clinical practice and; 4) evaluation in real-life patients. Whereas the CG went through the following teaching methodological processes: 1) theoretical background; 2) direct training in real-life patients and; 4) practical evaluation in a real-life patient. After each respective group intervention, both groups were assessed on their learning in 40 newborns at Santa Casa de Misericórdia do Pará Foundation in Belém, state of Pará, Brazil. Results: At the judges' evaluation regarding the simulator positive items (design, similarity, interest, relevance, content, memorization, didactics, previous reminiscence, comprehension and application), 49.2% answered 'strongly agree' and 44.4%, 'agree'. Regarding the negative questions (difficulty in understanding, information overload, abstraction, difficulty in handling and clarity of operation), 40.0% answered 'strongly disagree', and 57.1%, 'disagree'. The judges were 94.9% favorable to the use of the simulator in medical education. However, comparing the two groups of students, regarding the time of exam, the results showed no statistically significant difference (p-value = 0.29). Conclusions: The dummy showed its applicability for the learning of RRT, with the advantage of being able to perform the exam without having to disturb a real-life patient.

Resumo: Introdução: O Teste do Reflexo Vermelho (TRV) consiste em visualizar o reflexo que a luz causa na retina ao passar pela pupila. Dessa forma, o TRV tria patologias que levam à cegueira e pode reduzir o impacto social e econômico das famílias e do governo. O ensino por meio de simuladores permite que estudantes e profissionais de saúde adquiram e melhorem as habilidades clínicas. Objetivos: Este estudo teve como objetivos desenvolver um manequim de baixo custo, impresso em 3D e baseado na plataforma Arduino, para o treinamento do TRV em recém-nascidos e avaliar a eficácia educacional desse exame. Métodos: Um manequim do TRV foi apresentado a sete juízes especialistas - seis pediatras e um oftalmologista - que avaliaram a aplicabilidade do teste na aprendizagem médica. Para isso, utilizaram a escala Likert de 14 itens de 5 pontos. Posteriormente, 40 participantes participaram de um curso: 33 estudantes de Medicina, cinco residentes em pediatria, uma enfermeira e um médico generalista. Dividiram-se aleatoriamente os participantes em dois grupos: controle (GC) e experimental (GE). Cada grupo foi composto por 20 participantes. Submeteu-se o GC ao ensino convencional em pacientes reais. O GE passou por quatro etapas: 1. fundamentação teórica, 2. manipulação do simulador, 3. prática clínica simulada e 4. avaliação nos pacientes reais. No GC, adotaram-se os seguintes passos: 1. fundamentação teórica, 2. treinamento direto em pacientes reais e 3. avaliação em pacientes reais. Após a intervenção de cada grupo, os dois grupos foram avaliados quanto à aprendizagem em 40 recém-nascidos da Fundação Santa Casa de Misericórdia do Pará, em Belém, no Pará. Resultados: Na avaliação dos juízes em relação aos itens positivos para o simulador (design, similaridade, interesse, relevância, conteúdo, memorização, didática, reminiscência anterior, compreensão e aplicação), 49,2% afirmaram que concordavam fortemente e 44,4% mencionaram apenas que concordavam. Nas questões negativas (dificuldade de entendimento, sobrecarga de informação, abstração, dificuldade de manuseio e clareza de operação), 40,0% discordaram fortemente e 57,1% discordaram. Os juízes concordaram em 94,9% a favor do uso do simulador na educação médica. Porém, comparando os dois grupos de estudantes, em relação ao tempo de exame, os resultados não mostraram diferença estatisticamente significante (p = 0,29). Conclusão: O manequim mostrou aplicabilidade na aprendizagem do TRV, com a vantagem de realizar o exame sem que o paciente real fosse incomodado.

Melanin concentration and depolarization metrics measurement by polarization-sensitive optical coherence tomography.

Imaging of melanin in the eye is important as the melanin is structurally associated with some ocular diseases, such as age-related macular degeneration. Although optical coherence tomography (OCT) cannot distinguish tissues containing the melanin from other tissues intrinsically, polarization-sensitive OCT (PS-OCT) can detect the melanin through spatial depolarization of the backscattered light from the melanin granules. Entropy is one of the depolarization metrics that can be used to detect malanin granules in PS-OCT and valuable quantitative information on ocular tissue abnormalities can be retrived by correlating entropy with the melanin concentration. In this study, we investigate a relationship between the melanin concentration and some depolarization metrics including the entropy, and show that the entropy is linearly proportional to the melanin concentration in double logarithmic scale when noise bias is corrected for the entropy. In addition, we also confirm that the entropy does not depend on the incident state of polarization using the experimental data, which is one of important attributes that depolarization metrics should have. The dependence on the incident state of polarization is also analyzed for other depolarization metrics.

Use of 'U-shaped tool for follow up of corneal ulcer cases in the COVID-19 pandemic.

To describe a smartphone-based telemedicine tool for monitoring of corneal ulcer size during the corona pandemic, a simple "U"-shaped tool was constructed using three Schirmer's strips that were provided to the patients with small to medium-sized corneal ulcers. The patient and the attendant were trained to use this simple U-shaped tool at home and send digital images to the treating ophthalmologist, to monitor the course of the ulcer. The tool was used in five eyes of five patients with active microbial keratitis. Patients were followed up regularly with the use of telemedicine facility every 48 h for an average duration of 7.6 days (range 6-9 days). In all the five eyes, assessment of the serial images with U-shaped tool showed decrease in size of corneal ulcer, which corroborated with subjective improvement in symptoms. Hence, the novel "'U'-shaped tool" may provide an effective measure in following-up of corneal ulcer patients in times of the COVID-19 pandemic, obviating frequent hospital visits and risk of contracting COVID.

Image quality and diagnostic accuracy of a handheld nonmydriatic fundus camera: Feasibility of a telemedical approach in screening retinal diseases.

BACKGROUND: A suitable fundus camera for telemedicine screening can expand the scale of eye care service. The purpose of this study was to compare a handheld nonmydriatic digital fundus camera and a conventional mydriatic fundus camera according to the image quality of their photographs and usability of those photographs to accurately diagnose various retinal diseases. METHODS: A handheld nonmydriatic fundus camera and conventional fundus camera were used to take fundus photographs of outpatients at an ophthalmic clinic before and after pupillary dilation. Image quality and diagnostic agreement of the photos were graded by two masked and experienced retinal specialists. RESULTS: A total of 867 photographs of 393 eyes of 200 patients were collected. Approximately 80% of photos taken under nonmydriasis status using the handheld nonmydriatic fundus camera had good (55.7%) or excellent (22.7%) image quality. The overall agreement of diagnoses between the doctors was more than 90%. When the handheld nonmydriatic fundus camera was used after mydriasis, the proportion of images with good (45%) or excellent (49.7%) quality reached 94.7% and diagnostic agreement was 93.4%. Lens opacity was associated with the quality of images obtained using the handheld camera (p = 0.041), and diagnosis disagreement for handheld camera images was associated with preexisting diabetes diagnosis (p = 0.009). Approximately 40% of patients expressed preference for use of the handheld nonmydriatic camera. CONCLUSION: This study demonstrated the effectiveness of the handheld nonmydriatic fundus camera in clinical practice and its feasibility for telemedicine screening of retinal diseases.

Smartphone-Based Fundus Imaging-Where Are We Now?

With the advent of smartphone-based fundus imaging (SBFI), a low-cost alternative to conventional digital fundus photography has become available. SBFI allows for a mobile fundus examination, is applicable both with and without pupil dilation, comes with built-in connectivity and post-processing capabilities, and is relatively easy to master. Furthermore, it is delegable to paramedical staff/technicians and, hence, suitable for telemedicine. Against this background a variety of SBFI applications have become available including screening for diabetic retinopathy, glaucoma, and retinopathy of prematurity and its applications in emergency medicine and pediatrics. In addition, SBFI is convenient for teaching purposes and might serve as a surrogate for direct ophthalmoscopy. First wide-field montage techniques are available and the combination of SBFI with machine learning algorithms for image analyses is promising. In conclusion, SBFI has the potential to make fundus examinations and screenings for patients particularly in low- and middle-income settings more accessible and, therefore, aid tackling the burden of diabetic retinopathy, glaucoma, and retinopathy of prematurity screening. However, image quality for SBFI varies substantially and a reference standard for grading appears prudent. In addition, there is a strong need for comparison of different SBFI approaches in terms of applicability to disease screening and cost-effectiveness.

Medical legal validity of the use of the anomaloscope in the dyschromatopsia of aspiring civil and military aircraft pilots.

Color blindness is a condition of altered color perception, scientifically defined as "dyschromatopsia". Color blindness affects 8% of the world population. Color blindness is caused by an alteration of the cones that influences the vision of the color self (red, green, blue). A comparative study was conducted in dischromatopsic subjects identified during the course of the ordinary investigations directed towards the civil aero-navigating personnel by the Ophthalmology Department of the Air Force, between March 2019 and January 2020, at "Aldo Di Loreto" Institute of Aeronautical and Space Medicine of Rome. 10 subjects aged 20 to 50, with dyschromatopsia found at Ishihara's pseudoisochromatic tables, were submitted to Oculus HMC-Anomaloscope with a manual execution program and then a CAD test. Thus, in 2 out of 10 cases of dyschromatopsia, the Anomaloscope would have guided the medical judgement, while the CAD test would have oriented towards a judgment of full fitness despite the same lack of chromatic sensitivity however, underlined by both tests. In conclusion, the CAD test confirmed a highly sensitive and specific method of determining the presence and depth of the chromatic perception deficit but also the method was able to prevent the unjust refusal of certain air navigation activities to the aspirant staff.

A Comparison of Lower Eyelid Retraction in Normal Individuals with Positive versus Negative Orbital Vector.

PURPOSE: The present study aimed to compare lower eyelid retraction (LER) in individuals with a positive orbital vector with that of individuals with a negative orbital vector. MATERIALS AND METHODS: This cross-sectional study was conducted on 123 normal individuals including 64 men and 59 women aged 20-80 years. After the individuals underwent Hertel exophthalmometry, two side-view and front-view photos were taken using a camera. The orbital vector angle and the extent of scleral show were then measured in millimeter, using the Photoshop software. Eventually, the recorded data were analyzed through statistical software. RESULTS: The findings of this study showed that LER has a significant correlation with orbital vector angle and the extent of proptosis (P < 0.05). The mean value of orbital vector angle in individuals without LER was 9.76°, while this figure was calculated to be - 13.65° in individuals with LER. The mean protrusion value based on Hertel exophthalmometry was 14.08 mm in individuals without LER and 16.27 mm in individuals with LER. The extent of scleral show had a significant correlation with proptosis and orbital vector angle (P = 0.01), with a mean value of - 0.41 mm in individuals without LER and 0.94 mm in participants with LER. CONCLUSIONS: The prevalence of LER and scleral show is positively correlated with the extent of proptosis and negatively correlated with orbital vector angle.

Development of Feasible Methods to Image the Eyelid Margin Using In Vivo Confocal Microscopy.

PURPOSE: To develop a feasible method to image eyelid margin structures using in vivo confocal microscopy (IVCM) for use in clinical research. Second, to assess the association between IVCM and meibography images. METHODS: IVCM was performed on the central upper eyelid margin of 13 healthy participants (31 ± 5 years). Overall morphology montages (1600 × 1600 µm) were created of 3 participants. Single frames (400 × 400 µm) of 10 participants were imaged to determine the feasibility of measuring eyelid features. Meibography was performed with EASYTEARview+ in the same 10 participants. ImageJ software was used to quantify image structures. RESULTS: In the montages, structures of rete ridges, meibomian gland openings, and the lid wiper region were observed. The maximum possible montage size, using multiple single frames, was approximately 5200 × 1500 × 150 µm in the X, Y, and Z directions, respectively. The mean number, density, area, perimeter, and shortest and longest diameters of rete ridges of the 9 nonoverlapped frames were 12 ± 2/frame, 73 ± 5/mm, 2504 ± 403 µm, 250 ± 33 µm, 40 ± 6 µm, and 84 ± 13 µm, respectively. Sampling analysis determined at least 5 nonoverlapped frames were necessary to accurately represent the parameters of the ridges. The mean areas of 3 meibomian openings were 785 ± 784 µm, 1036 ± 963 µm, 950 ± 1071 µm, 848 ± 954 µm, 737 ± 831 µm, 735 ± 743 µm, and from 30 µm to 130 µm at 20-µm depth intervals, respectively. No significant association between IVCM and meibography parameters (P = 0.53) was found. CONCLUSIONS: Imaging rete ridges with IVCM should include at least 5 nonoverlapping single frames in the upper eyelid margin. At least 3 openings imaged between 30 and 130 µm at 20-µm depth intervals are recommended to determine the opening area.