Investigation of How Corneal Densitometry Artefacts Affect the Imaging of Normal and Keratoconic Corneas.

PURPOSE: To investigate corneal densitometry artefacts found in Pentacam Scheimpflug scans and their potential effect on assessing keratoconic (KC) corneas compared to normal (N) corneas. METHODS: The current study utilises Pentacam data of 458 N eyes, aged 35.6 ± 15.8 (range 10-87), referred to as the "N group", and 314 KC eyes, aged 31.6 ± 10.8 (range 10-72), referred to as the "KC group", where densitometry data were extracted and analysed via a custom-built MATLAB code. Radial summations of the densitometry were calculated at diameters ranging from 0.5 mm to 5.0 mm. The minimum normalised radial summation of densitometry (NRSD) value and angle were determined at each diameter and then linked. KC cone locations and areas of pathology were determined, and a comparison between N and KC groups was carried out both within the averaged area of pathology and over the corneal surface. RESULTS: Joining minimum NRSD trajectory points marked a clear distortion line pointing to the nasal-superior direction at 65° from the nasal meridian. The findings were found to be independent of eye laterality or ocular condition. Consistency was detected in the right and left eyes among both the N and KC groups. The location of the KC cone centre and the area of pathology were determined, and the densitometry output was compared both within the area of pathology and over the whole cornea. When the average densitometry was compared between N and KC eyes within the KC area of pathology, the N group recorded a 16.37 ± 3.15 normalised grey-scale unit (NGSU), and the KC group recorded 17.74 ± 3.4 NGSU (p = 0.0001). However, when the whole cornea was considered, the N group recorded 16.71 ± 5.5 NGSU, and the KC group recorded 15.72 ± 3.98 NGSU (p = 0.0467). A weak correlation was found between the Bad D index and NGSU when the whole measured cornea was considered (R = -0.01); however, a better correlation was recorded within the KC area of pathology (R = 0.21). CONCLUSIONS: Nasal-superior artefacts are observed in the densitometry Pentacam maps, and analysis shows no significant differences in their appearance between N or KC corneas. When analysing KC corneas, it was found that the cone positions are mostly on the temporal-inferior side of the cornea, opposite to the densitometry artefact NRSD trajectory. The analysis suggests that the corneal densitometry artefacts do not interfere with the KC area of pathology as it reaches its extreme in the opposite direction; therefore, weighting the densitometry map to increase the contribution of the inferior-temporal cornea and decreasing that of the superior-nasal area would improve the classification or identification of KC if densitometry is to be used as a KC metric.

Assessment of Preoperative Risk Factors for Post-LASIK Ectasia Development.

Purpose: To evaluate preoperative risk factors (mainly those related to corneal topography/tomography) for post-LASIK ectasia development. Methods: A retrospective case review for post-LASIK ectasia for myopia or myopic astigmatism. The evaluated data included preoperative subjective refraction, method of flap creation, and topometric/tomographic parameters from Oculus Pentacam, including subjective curvature pattern, topometric, elevation, and pachymetric indices from the Belin Ambrosio display "BAD", and the Pentacam Random Forest Index (PRFI). Moreover, preoperative ectasia detection indices were calculated (including Percentage of Tissue Altered "PTA" index, Randleman Ectasia Risk Score System "ERSS", and Navarro Index for Corneal Ectasia "NICE"). Results: Twenty-four eyes of 15 patients were enrolled. Concerning the risk factors, age was lower than 25 in 19 eyes (79%); flaps were created using a microkeratome in 17 eyes (70.8%); thinnest pachymetry was lower than 510µm in eight eyes (33%); total deviation from BAD was higher than 1.6 in 50%; Ambrósio's relational thickness (ART) max was lower than 340 in 45.83%; PTA index was higher than 40% in 16%; ERSS was more than 3 points in 62.5%; NICE was higher than 8 points in three eyes (12.5%); PRFI index was more than 0.125 in 87.5%; two eyes (8%) had no identifiable risk factors. Conclusion: Current ectasia risk assessment criteria were insufficient for detecting a relatively large number of cases. There is an unequivocal need for more information, which may be derived from biomechanical assessment and epithelial thickness mapping. Novel corneal tomography indices derived from artificial intelligence may increase accuracy in characterizing ectasia susceptibility.

Multimodal diagnostics for keratoconus and ectatic corneal diseases: a paradigm shift.

Different diagnostic approaches for ectatic corneal diseases (ECD) include screening, diagnosis confirmation, classification of the ECD type, severity staging, prognostic evaluation, and clinical follow-up. The comprehensive assessment must start with a directed clinical history. However, multimodal imaging tools, including Placido-disk topography, Scheimpflug three-dimensional (3D) tomography, corneal biomechanical evaluations, and layered (or segmental) tomography with epithelial thickness by optical coherence tomography (OCT), or digital very high-frequency ultrasound (dVHF-US) serve as fundamental complementary exams for measuring different characteristics of the cornea. Also, ocular wavefront analysis, axial length measurements, corneal specular or confocal microscopy, and genetic or molecular biology tests are relevant for clinical decisions. Artificial intelligence enhances interpretation and enables combining such a plethora of data, boosting accuracy and facilitating clinical decisions. The applications of diagnostic information for individualized treatments became relevant concerning the therapeutic refractive procedures that emerged as alternatives to keratoplasty. The first paradigm shift concerns the surgical management of patients with ECD with different techniques, such as crosslinking and intrastromal corneal ring segments. A second paradigm shift involved the quest for identifying patients at higher risk of progressive iatrogenic ectasia after elective refractive corrections on the cornea. Beyond augmenting the sensitivity to detect very mild (subclinical or fruste) forms of ECD, ectasia risk assessment evolved to characterize the inherent susceptibility for ectasia development and progression. Furthermore, ectasia risk is also related to environmental factors, including eye rubbing and the relational impact of the surgical procedure on the cornea.

Biomechanics in Keratoconus Diagnosis.

Purpose: To prospectively review the importance of biomechanical assessment in the screening, diagnosis, prognosis, individualized planning, and clinical follow-up for ectatic corneal diseases.Methods: We demonstrate two commercially available devices to assess the corneal biomechanics in vivo, the Ocular Response Analyzer (ORA, Reichester, NY, USA) and the Corvis ST (Oculus, Wetzlar, Germany). Novel devices have been demonstrated to provide in vivo biomechanical measurements, including Brillouin optical microscopy and OCT elastography. Conclusion: The integration of biomechanical data and other data from multimodal refractive imaging using artificial intelligence demonstrated the ability to enhance accuracy in diagnosing ectatic corneal diseases.

Corneal ectasia detection by epithelial pattern standard deviation from OCT.

PURPOSE: To test the ability of the corneal epithelial pattern standard deviation (PSD) to distinguish between normal and cases with corneal ectatic condition. SETTING: Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil. DESIGN: Cross-sectional retrospective study. METHODS: Patients were stratified into 4 groups based on clinical data and corneal tomography. Groups 1 and 2 comprised 1 eye randomly selected from 105 patients with normal corneas (N) and 86 patients with bilateral keratoconus (KC). Groups 3 and 4, respectively, comprised 11 ectatic eyes with no surgical treatment for KC (very asymmetric ectasia [VAE]-E) from patients whose fellow eyes (61) presented with normal topographic patterns (VAE-NT). Corneas were scanned using an OCT system (RT Vue) and Scheimpflug corneal tomography (Pentacam) and also had biomechanical assessment through the Corvis ST. Corneal epithelial thickness maps were analyzed, and the PSD value was calculated. The area under the receiver operating characteristic curve analysis was used to evaluate the diagnostic accuracy of the indices. RESULTS: A total of 105 normal eyes, 86 keratoconic eyes, and 11 ectatic eyes whose fellow eyes (61) presented normal topographic patterns were evaluated. Epithelial PSD was significantly different across the 4 groups ( P < .0001). The pairwise comparison revealed that the normal group presented significantly lower values than both ectasia groups (KC and VAE-E, P < .0001) and the VAE-NT group ( P = .0008). There was no statistical significant difference between KC and VAE-E ( P = .4284), while they were significantly higher than the VAE-NT group ( P < .0001 and P = .0004). CONCLUSIONS: Epithelial PSD can be used to detect abnormal epithelial thickness patterns. Corneal epithelial thickness changes could be detected accurately in patients with KC, even in the form fruste of the disease.

Optimized Artificial Intelligence for Enhanced Ectasia Detection Using Scheimpflug-Based Corneal Tomography and Biomechanical Data.

PURPOSE: To optimize artificial intelligence (AI) algorithms to integrate Scheimpflug-based corneal tomography and biomechanics to enhance ectasia detection. DESIGN: Multicenter cross-sectional case-control retrospective study. METHODS: A total of 3886 unoperated eyes from 3412 patients had Pentacam and Corvis ST (Oculus Optikgeräte GmbH) examinations. The database included 1 eye randomly selected from 1680 normal patients (N) and from 1181 "bilateral" keratoconus (KC) patients, along with 551 normal topography eyes from patients with very asymmetric ectasia (VAE-NT), and their 474 unoperated ectatic (VAE-E) eyes. The current TBIv1 (tomographic-biomechanical index) was tested, and an optimized AI algorithm was developed for augmenting accuracy. RESULTS: The area under the receiver operating characteristic curve (AUC) of the TBIv1 for discriminating clinical ectasia (KC and VAE-E) was 0.999 (98.5% sensitivity; 98.6% specificity [cutoff: 0.5]), and for VAE-NT, 0.899 (76% sensitivity; 89.1% specificity [cutoff: 0.29]). A novel random forest algorithm (TBIv2), developed with 18 features in 156 trees using 10-fold cross-validation, had a significantly higher AUC (0.945; DeLong, P < .0001) for detecting VAE-NT (84.4% sensitivity and 90.1% specificity; cutoff: 0.43; DeLong, P < .0001) and a similar AUC for clinical ectasia (0.999; DeLong, P = .818; 98.7% sensitivity; 99.2% specificity [cutoff: 0.8]). Considering all cases, the TBIv2 had a higher AUC (0.985) than TBIv1 (0.974; DeLong, P < .0001). CONCLUSIONS: AI optimization to integrate Scheimpflug-based corneal tomography and biomechanical assessments augments accuracy for ectasia detection, characterizing ectasia susceptibility in the diverse VAE-NT group. Some patients with VAE may have true unilateral ectasia. Machine learning considering additional data, including epithelial thickness or other parameters from multimodal refractive imaging, will continuously enhance accuracy. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Investigation of the relationship between contact lens design parameters and refractive changes in Ortho-K.

Purpose: To investigate the relationship between Ortho-K contact lens design parameters and refractive power change of the eye through a parametric mathematical representation. Methods: The current study utilises fully anonymized records of 249 eyes, 132 right eyes, and 117 left eyes from subjects aged 14.1 ± 4.0 years on average (range 9-38 years) which were selected for secondary analysis processing. The data were split into 3 groups (G1 up to 35 days wear, from 10 to 35 days, G2 up to 99 days wear, more than 35-99 days & G3 more than 100 days wear) according to the length of time, in days, that the lenses were worn. Corneal shape was measured before and after contact lens wear using the Medmont E300 topographer, from which height and distance files were read by a custom-built MATLAB code to construct the corneal anterior surface independently. Changes in refractive power pre and post-Ortho-K wear were determined using constructed tangential refractive power maps from which both centrally flattened and annular steepened zones were automatically bounded, hence used to determine the refractive power change. Results: On average, flat Sim-K and steep Sim-K were reduced after Ortho-K lens wear by 1.6 ± 1.3 D and 1.3 ± 1.4 D respectively. The radius of the base curve was correlated with the mean central flattened zone power change strongly in G1 (R = 0.7, p < 0.001) and moderately in G2 (R = 0.4) and G3 (R = 0.4, p < 0.001). Hence, a strong correlation with the base curve was recorded in group G1 and moderate in G2 and G3. The reverse curve was very strongly correlated to the mean central flattened zone power change in G1 (R = 0.8, p < 0.001) and strongly correlated with G2 (R = 0.6, p < 0.001) and G3 (R = 0.7, p < 0.001). The reverse curve was also strongly correlated with the mean annular steepened zone power change among all groups G1, G2, and G3 (R = 0.7, R = 0.6 and R = 0.6) respectively (p < 0.001). Conclusions: Although the central corneal refractive power change was strongly correlated to the Ortho-K lens base curve, it characterized only 50% of the target power change. However, the annular steepened zone refractive power change appears to be a clearer predictor of target power change, as there appears to be a one-to-one inverse relationship with the target refractive power correction. Differences between these results and the literature may be a result of the topography software smoothing effect.

Enhanced Diagnostics for Corneal Ectatic Diseases: The Whats, the Whys, and the Hows.

There are different fundamental diagnostic strategies for patients with ectatic corneal diseases (ECDs): screening, confirmation of the diagnosis, classification of the type of ECD, severity staging, prognostic assessment, and clinical follow-up. The conscious application of such strategies enables individualized treatments. The need for improved diagnostics of ECD is related to the advent of therapeutic refractive procedures that are considered prior to keratoplasty. Among such less invasive procedures, we include corneal crosslinking, customized ablations, and intracorneal ring segment implantation. Besides the paradigm shift in managing patients with ECD, enhancing the sensitivity to detect very mild forms of disease, and characterizing the inherent susceptibility for ectasia progression, became relevant for identifying patients at higher risk for progressive iatrogenic ectasia after laser vision correction (LVC). Moreover, the hypothesis that mild keratoconus is a risk factor for delivering a baby with Down's syndrome potentially augments the relevance of the diagnostics of ECD. Multimodal refractive imaging involves different technologies, including Placido-disk corneal topography, Scheimpflug 3-D tomography, segmental or layered tomography with layered epithelial thickness using OCT (optical coherence tomography), and digital very high-frequency ultrasound (VHF-US), and ocular wavefront. Corneal biomechanical assessments and genetic and molecular biology tests have translated to clinical measurements. Artificial intelligence allows for the integration of a plethora of clinical data and has proven its relevance in facilitating clinical decisions, allowing personalized or individualized treatments.

Corneal biomechanics for corneal ectasia: Update.

Knowledge of biomechanical principles has been applied in several clinical conditions, including correcting intraocular pressure measurements, planning and following corneal treatments, and even allowing an enhanced ectasia risk evaluation in refractive procedures. The investigation of corneal biomechanics in keratoconus (KC) and other ectatic diseases takes place in several steps, including screening ectasia susceptibility, the diagnostic confirmation and staging of the disease, and also clinical characterization. More recently, investigators have found that the integration of biomechanical and tomographic data through artificial intelligence algorithms helps to elucidate the etiology of KC and ectatic corneal diseases, which may open the door for individualized or personalized medical treatments in the near future. The aim of this article is to provide an update on corneal biomechanics in the screening, diagnosis, staging, prognosis, and treatment of KC.

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.

Ocular manifestations of Chikungunya fever in the chronic phase / Manifestações oculares na fase crônica da febre Chikungunya

ABSTRACT Purpose: To identify ocular manifestations in patients with Chikungunya fever in the chronic phase and describe their sociodemographic profile. Methods: Patients with serologic confirmation of Chikungunya infection were included in this transverse study. All subjects underwent a comprehensive ophthalmologic evaluation, including specific lacrimal function tests (tear break-up time test, Schirmer test, and lissamine green). Results: Overall, 64 eyes of 32 patients were evaluated. Most patients were women (71.9%), with the mean age of 50.0 ±13.7 years. The mean interval between serologic confirmation and the examination was 12.7 ±7.7 months. Twenty patients (62%) presented with dry eye. No statistically significant association was observed between dry eye and infection diagnosis time (p=0.5546), age (p=0.9120), sex (p=1.00), race (p=0.2269), arthralgia in acute infection (p=0.7930), retro-orbital pain (p=0.3066), and conjunctivitis (p=1.00). Conclusion: Dry eye was the most prevalent manifestation observed. No signs of intraocular inflammation and affected visual acuity were observed.

RESUMO Objetivo: Identificar manifestações oculares em pacientes na fase crônica da febre Chikungunya e descrever seu perfil sociodemográfico. Métodos: Estudo transversal com a inclusão de pacientes com confirmação sorológica de febre Chikungunya. Todos os pacientes foram submetidos a exame oftalmológico completo, incluindo testes específicos de função lacrimal (teste de ruptura do filme lacrimal, teste de Schirmer e teste da lissamina verde). Resultados: Foram avaliados 64 olhos de 32 pacientes. A maioria dos pacientes eram do sexo feminino (71,9%) e a idade média foi 50,0 ±13,7 anos. O intervalo médio entre a confirmação sorológica e o exame oftalmológico foi de 12,7 ±7,7 meses. Vinte pacientes (62%) apresentaram olho seco. Não houve significância estatística na associação entre olho seco e o tempo de diagnóstico da infecção (p=0,5546), idade (p=0,9120), sexo (p=1,00), raça (p=0,2269), artralgia durante a infecção aguda (p=0,7930), dor retro-orbitária (p=0,3066) e conjuntivite (p=1,00). Conclusão: A presença de olho seco foi a manifestação mais prevalente observada. Não foram observa dos sinais de inflamação intraocular ou baixa acuidade visual.

Ocular manifestations of Chikungunya fever in the chronic phase.

PURPOSE: To identify ocular manifestations in patients with Chikungunya fever in the chronic phase and describe their sociodemographic profile. METHODS: Patients with serologic confirmation of Chikungunya infection were included in this transverse study. All subjects underwent a comprehensive ophthalmologic evaluation, including specific lacrimal function tests (tear break-up time test, Schirmer test, and lissamine green). RESULTS: Overall, 64 eyes of 32 patients were evaluated. Most patients were women (71.9%), with the mean age of 50.0 ±13.7 years. The mean interval between serologic confirmation and the examination was 12.7 ±7.7 months. Twenty patients (62%) presented with dry eye. No statistically significant association was observed between dry eye and infection diagnosis time (p=0.5546), age (p=0.9120), sex (p=1.00), race (p=0.2269), arthralgia in acute infection (p=0.7930), retro-orbital pain (p=0.3066), and conjunctivitis (p=1.00). CONCLUSION: Dry eye was the most prevalent manifestation observed. No signs of intraocular inflammation and affected visual acuity were observed.

Caracterização de ectasia subclínica com análise integrada da tomografia e biomecânica da córnea / Characterization of subclinical ectasia with integrated corneal tomography and biomechanics assessments

RESUMO O artigo tem como objetivo descrever de forma prospectiva diferentes casos de ectasias altamente assimétricas (very asymmetric ectasia, VAE) para diferenciar formas subclínicas ou "frustas" do ceratocone (forme fruste keratoconus - FFKC) de casos de doença ectásica unilateral. O Caso 1 é um paciente de 39 anos, que admitiu ter coçado intensamente apenas o olho direito (OD) na juventude, se apresentando com ectasia unilateral tratada com sucesso por meio de implante de anel intraestromal em OD. O olho esquerdo (OE) apresentou-se normal ao exame completo por meio de propedêutica multimodal e acuidade visual não corrigida (AVsc) de 20/20, estável por mais de 5 anos, com TBI (tomography and biomechanical index) de 0.02. No Caso 2 é um paciente de 15 anos com ectasia clínica em OD, e OE com topografia normal, mas alterações tomográficas e biomecânicas, incluindo o TBI 0,56, caracterizarando a doença subclínica (FFKC). O Caso 3 é a mãe do paciente do Caso 2, de 46 anos, que se apresentou com presbiopia, sem qualquer histórico oftalmológico relevante. A AVsc foi de 20/20 em cada olho, topografia de Placido com leve encurvamento inferior, mas sem sinais definitivos de ectasia. A avaliação biomecânica e tomográfica revelou sinais de ceratocone em ambos os olhos, com TBI de 1,0 e 0,99. Esses três casos estão de acordo com a definição do consenso global e a hipótese de dois acertos (two-hit hypothesis), que ceratocone é uma doença bilateral, mas ectasia pode ocorrer por causa estritamente mecânica unilateralmente (ou em qualquer olho). A relevância da propedêutica multimodal é destacada, destacando-se a integração do estudo biomecânico e tomográfico com imagens de Scheimpflug.

ABSTRACT The article aims to prospectively describe different cases of highly asymmetric ectasia (very asymmetric ectasia, VAE) to differentiate subclinical or "frustrated" forms of keratoconus (forme fruste keratoconus - FFKC) from cases of unilateral ectatic disease. Case 1 is a 39-year-old patient with unilateral ectasia treated with an intrastromal ring implant. The contralateral eye was normal due to multimodal propaedeutics, stable for more than 3 years, with a TBI of 0.02. The patient admitted to having intensely scratched only his right eye in his youth. In Case 2, a 15-year-old patient with clinical ectasia in the right eye, had a left eye with normal topography and tomographic and biomechanical changes characterizing FFKC. Case 3 is the mother of the case 2 patient, aged 46, who presented with presbyopia, without any relevant ophthalmological history. Uncorrected visual acuity of 20/20 in each eye, Placido topography with slight lower curving, but without definitive signs of ectasia. The biomechanical and tomographic evaluation revealed signs of keratoconus in both eyes. These three cases are in accordance with the definition of the global consensus: keratoconus is a bilateral disease, but ectasia can occur because of strictly mechanical unilateral (in any eye). The relevance of multimodal refractive imaging is highlighted, with a focus on integrating biomechanical and tomographic assessments with Scheimpflug images.

Ectatic diseases.

Ectatic corneal disease (ECD) comprises a group of disorders characterized by progressive thinning and subsequent bulging of the corneal structure. Different phenotypes have been recognized, including keratoglobus, pellucid marginal degeneration (PMD), and keratoconus (KC). Keratoconus has been widely investigated throughout the years, but the advent of laser refractive surgery boosted an immediate need for more knowledge and research about ectatic diseases. This article discusses nomenclature of ectatic disease, etiology and pathogenesis, along with treatment options, with special focus ok KC and forme fruste keratoconus.

Diagnóstico do ceratocone: um artigo de revisão / A review of keratoconus diagnosis

Resumo Objetivo: Realizar uma revisão sobre o diagnóstico do ceratocone, com enfoque nos métodos propedêuticos disponíveis. Métodos: Foi realizada uma pesquisa no banco de dados PubMed com as palavras chave: Keratoconus, diagnosis, topography e tomography. Por se tratar de uma revisão, não houve restrição de período para a publicação dos artigos selecionados. Foram também utilizados o manual Prefered Practice Pattern(PPP) da academia americana de oftalmologia, assim como o site "eyewiki.aao.org". Resultados: Dos 641 artigos encontrados no PubMed, assim como os usados como referência para o PPP, 36 foram selecionados por serem considerados mais relevantes para o tema proposto. O site "eyewiki.aao.org" foi utilizado como referência para as figuras. Conclusão: O diagnóstico do ceratocone evoluiu consideravelmente desde quando foi primeiramente descrito. É desejável que seja feito em suas fases precoces devido ao alto potencial de morbidade desta doença. Uma possível integração entre os múltiplos índices diagnósticos, investigação genética, biologia molecular e inteligência artificial é almejado para uma maior acurácia diagnóstica.

Abstract Objective: To Perform a review on the diagnosis of keratoconus, focusing on the available propaedeutic methods. Methods: A search was performed in the PubMed database using the key words: Keratoconus, diagnosis, topography and tomography. As it is a review, there was no restriction regarding the publication period of the selected articles. Furthermore, both the preferred practice pattern(PPP) manual of the American Academy of Ophthalmology, as well as the website "eyewiki.aao.org" were used as reference. The project was submitted to the research ethics committee of the Federal University of São Paulo / UNIFESP / SP 2018 (# 2,568,770). Results: Out of the 641 papers found in PubMed, in adition to those used as a reference for PPP, 36 were selected while considered more relevant to the adopted theme. The website "eyewiki.aao.org" was used as a reference for the images. Conclusion: The diagnosis of keratoconus has evolved considerably since it was first described. It is desirable to diagnose it on the early stages due to its high potential of morbility. A possibility of an integration between the various diagnostic indices, genetic research, molecular biology and artificial intelligence is recommended for greater diagnostic accuracy.

Advanced Surface Ablation in Mild (Fruste) Keratoconus: A Case Report.

Corneal ectasia is a complication of refractive surgery, and keratoconus is a contraindication to this type of procedure. Surface ablation may be an option for selected cases of mild keratoconus, with patient education being fundamental to this treatment as well as a complete evaluation of the cornea and optical properties of the patient. Here we report the clinical outcome of a patient 15 years after advanced surface ablation in a case of mild (fruste) keratoconus.

The Role of Corneal Biomechanics for the Evaluation of Ectasia Patients.

PURPOSE: To review the role of corneal biomechanics for the clinical evaluation of patients with ectatic corneal diseases. METHODS: A total of 1295 eyes were included for analysis in this study. The normal healthy group (group N) included one eye randomly selected from 736 patients with healthy corneas, the keratoconus group (group KC) included one eye randomly selected from 321 patients with keratoconus. The 113 nonoperated ectatic eyes from 125 patients with very asymmetric ectasia (group VAE-E), whose fellow eyes presented relatively normal topography (group VAE-NT), were also included. The parameters from corneal tomography and biomechanics were obtained using the Pentacam HR and Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany). The accuracies of the tested variables for distinguishing all cases (KC, VAE-E, and VAE-NT), for detecting clinical ectasia (KC + VAE-E) and for identifying abnormalities among the VAE-NT, were investigated. A comparison was performed considering the areas under the receiver operating characteristic curve (AUC; DeLong's method). RESULTS: Considering all cases (KC, VAE-E, and VAE-NT), the AUC of the tomographic-biomechanical parameter (TBI) was 0.992, which was statistically higher than all individual parameters (DeLong's; p < 0.05): PRFI- Pentacam Random Forest Index (0.982), BAD-D- Belin -Ambrosio D value (0.959), CBI -corneal biomechanical index (0.91), and IS Abs- Inferior-superior value (0.91). The AUC of the TBI for detecting clinical ectasia (KC + VAE-E) was 0.999, and this was again statistically higher than all parameters (DeLong's; p < 0.05): PRFI (0.996), BAD-D (0.995), CBI (0.949), and IS Abs (0.977). Considering the VAE-NT group, the AUC of the TBI was 0.966, which was also statistically higher than all parameters (DeLong's; p < 0.05): PRFI (0.934), BAD- D (0.834), CBI (0.774), and IS Abs (0.677). CONCLUSIONS: Corneal biomechanical data enhances the evaluation of patients with corneal ectasia and meaningfully adds to the multimodal diagnostic armamentarium. The integration of biomechanical data and corneal tomography with artificial intelligence data augments the sensitivity and specificity for screening and enhancing early diagnosis. Besides, corneal biomechanics may be relevant for determining the prognosis and staging the disease.

Biomechanical diagnostics of the cornea.

Corneal biomechanics has been a hot topic for research in contemporary ophthalmology due to its prospective applications in diagnosis, management, and treatment of several clinical conditions, including glaucoma, elective keratorefractive surgery, and different corneal diseases. The clinical biomechanical investigation has become of great importance in the setting of refractive surgery to identify patients at higher risk of developing iatrogenic ectasia after laser vision correction. This review discusses the latest developments in the detection of corneal ectatic diseases. These developments should be considered in conjunction with multimodal corneal and refractive imaging, including Placido-disk based corneal topography, Scheimpflug corneal tomography, anterior segment tomography, spectral-domain optical coherence tomography (SD-OCT), very-high-frequency ultrasound (VHF-US), ocular biometry, and ocular wavefront measurements. The ocular response analyzer (ORA) and the Corvis ST are non-contact tonometry systems that provide a clinical corneal biomechanical assessment. More recently, Brillouin optical microscopy has been demonstrated to provide in vivo biomechanical measurements. The integration of tomographic and biomechanical data into artificial intelligence techniques has demonstrated the ability to increase the accuracy to detect ectatic disease and characterize the inherent susceptibility for biomechanical failure and ectasia progression, which is a severe complication after laser vision correction.

Manifestações oculares na febre Chikungunya / Ocular Manifestations of Chikungunya Fever

Resumo A febre Chikungunya é um problema de saúde pública mundial, com potencial para gerar epidemias de alta morbidade, visto que elevado número de pacientes pode apresentar sequelas articulares prolongadas e alterações oftalmológicas. As manifestações oftalmológicas podem estar presentes na fase aguda da doença ou ter início após várias semanas da instalação do quadro. Na literatura mundial é descrito desde alterações mais comuns e de fácil tratamento como conjuntivites até alterações mais complexas e que podem cursar com sequelas visuais graves como a retinite e neurite óptica.

Abstract Chikungunya fever is a world public health problem with the potential to generate epidemics of high morbidity, since a high number of patients may present prolonged joint sequelae and ophthalmological alterations. Ophthalmologic manifestations may be present in the acute phase of the disease or begin after several weeks of the onset of the disease. In the world literature is described from more common and easy to treat changes such as conjunctivitis to more complex changes and that can occur with severe visual sequelae such as retinitis and optic neuritis.