Machine learning based endothelial cell image analysis of patients undergoing descemet membrane endothelial keratoplasty surgery.

OBJECTIVES: In this study, we developed a machine learning approach for postoperative corneal endothelial cell images of patients who underwent Descemet's membrane keratoplasty (DMEK). METHODS: An AlexNet model is proposed and validated throughout the study for endothelial cell segmentation and cell location determination. The 506 images of postoperative corneal endothelial cells were analyzed. Endothelial cell detection, segmentation, and determining of its polygonal structure were identified. The proposed model is based on the training of an R-CNN to locate endothelial cells. Next, by determining the ridges separating adjacent cells, the density and hexagonality rates of DMEK patients are calculated. RESULTS: The proposed method reached accuracy and F1 score rates of 86.15 % and 0.857, respectively, which indicates that it can reliably replace the manual detection of cells in vivo confocal microscopy (IVCM). The AUC score of 0.764 from the proposed segmentation method suggests a satisfactory outcome. CONCLUSIONS: A model focused on segmenting endothelial cells can be employed to assess the health of the endothelium in DMEK patients.

Predicting Success in Descemet Membrane Endothelial Keratoplasty Surgery Using Machine Learning.

PURPOSE: This study aimed to predict early graft failure (GF) in patients who underwent Descemet membrane endothelial keratoplasty based on donor characteristics. METHODS: Several machine learning methods were trained to predict GF automatically. To predict GF, the following variables were obtained: donor age, sex, systemic diseases, medications, duration of stay in the intensive care unit, death-to-preservation time (DPT), endothelial cell density of the cornea, tightness of Descemet membrane roll during surgery, anterior chamber tamponade, tamponade used for rebubbling, and preoperative best corrected visual acuity. Five classification methods were experimented with the study data set: random forest, support vector machine, k-nearest neighbor, RUSBoosted tree, and neural networks. In holdout validation, 75% of the data were used in training and the remaining 25% used in testing. The predictive accuracy, sensitivity, specificity, f-score, and area under the receiver operating characteristic curve of the methods were evaluated. RESULTS: The highest classification accuracy achieved during the experiments was 96%. The precision, recall, and f1-score values were 0.95, 0.81, and 0.90, respectively. Feature importance was also computed using analysis of variance. The model revealed that GF risk was related to DPT and the intensive care unit duration (P < 0.05). No significant relationship was found between donor age, endothelial cell density, systemic diseases and medications, graft roll, tamponades, and GF risk. CONCLUSIONS: This study shows a strong relationship between increased intensive care duration, DPT, and GF. Experimental results demonstrate that machine learning methods may effectively predict GF automatically.

Accelerated corneal cross-linking with hypo-osmolar riboflavin in thin keratoconic corneas: 2-year follow-up / Cross-linking corneano acelerado com riboflavina hiposmolar em córneas ceratocônicas finas: 2 anos de acompanhamento

ABSTRACT Purpose: This study was performed to evaluate the outcomes of accelerated corneal cross-linking in keratoconic corneas with thinnest pachymetry values of <400 µm. Methods: The study included 28 eyes of 24 patients. The uncorrected and best-corrected visual acuities (logMAR), flattest and steepest keratometric readings, central corneal thickness at the thinnest point, corneal higher-order aberrations, and contrast sensitivity were assessed before and at 1, 3, 6, 12, and 24 months after corneal cross-linking. Result: The mean best-corrected visual acuity and contrast sensitivity increased (p=0.02, p=0.03, respectively), whereas the mean uncorrected visual acuity did not significantly differ (p>0.05) at 24 months after corneal cross-linking, compared with measurements before corneal cross-linking. Although the mean flattest keratometric reading showed no significant change (p=0.58), the mean steepest keratometric reading was reduced when compared with its value before corneal cross-linking (p=0.001). No change was observed in the mean central corneal thickness at the thinnest point at 24 months after corneal cross-linking, compared with its value before corneal cross-linking (p=0.12). Conclusion: Accelerated corneal cross-linking in keratoconic eyes with thin corneas could halt the progression of keratoconus in corneas thinner than 400 µm at 24 months after treatment.

RESUMO Objetivo: Este estudo foi realizado para avaliar os resultados do cross-linking corneano acelerado em córneas ceratocônicas com os valores mais baixos de paquimetria <400 µm. Métodos: O estudo incluiu 28 olhos de 24 pacientes. As acuidades visuais não corrigidas e melhor corrigidas (logMAR), leituras ceratométricas mais planas e íngremes, espessura corneana central no ponto mais fino, aberrações corneanas de mais alta ordem e a sensibilidade ao contraste foram avaliadas antes e em 1, 3, 6, 12 e 24 meses após a realização do do cross-linking. Resultados: A média da acuidade visual melhor corrigida e a sensibilidade ao contraste aumentaram (p=0,02, p=0,03, respectivamente), enquanto a média da acuidade visual não corrigida não diferiu significativamente (p>0,05) aos 24 meses após o cross-linking, comparada com medidas antes do procedimento. Embora a leitura da média da ceratometria mais plana não tenha apresentado alteração significativa (p=0,58), a leitura ceratométrica mais íngreme diminuiu quando comparada ao seu valor antes do cross-linking (p=0,001). Não foi observada alteração na média da espessura corneana central no ponto mais fino aos 24 meses após o cross-linking em comparação com seu valor antes do procedimento (p=0,12). Conclusão: O cross-linking corneano acelerado nos olhos ceratocônicos com córneas finas pode interromper a progressão do ceratocone nas córneas mais finas que 400 µm 24 meses após o tratamento.

Clinical outcomes of ocular surface in patients treated with vitamin D oral replacement / Resultados clínicos da superfície ocular em pacientes tratados com reposição oral de vitamina D

ABSTRACT Purpose: To analyze the clinical outcomes of the ocular surface in patients with vitamin D deficiency after oral replacement. Methods: A total of 40 patients with vitamin D deficiency were enrolled in the study. The patients received 50,000 units of oral vitamin D weekly over a period of 8 weeks. After 8 weeks, 1,500-2,000 units/d were administered for 24 weeks. Eyelid margin score, meibomian gland expressibility score, Oxford grading, Schirmer I test, tear breakup time, tear osmolarity, and the Ocular Surface Disease Index score were evaluated at baseline, and at 8, 12, and 24 weeks. Results: The meibomian gland expressibility score, Schirmer I, tear breakup time, tear osmolarity, and Ocular Surface Disease Index score showed improvement 8 weeks after vitamin D supplementation (p<0.05). Compared with the pretreatment values, the eyelid margin score and Oxford grading were decreased at week 12 (p<0.05). Conclusion: Vitamin D replacement appears to improve ocular surface in individuals with vitamin D deficiency.

RESUMO Objetivo: Analisar os resultados clínicos da superfície ocular em pacientes com deficiência de vitamina D após reposição oral. Métodos: Foram incluídos no estudo 40 pacientes com deficiência de vitamina D. Os pacientes receberam 50.000 unidades de vitamina D semanalmente por um período de oito semanas. Após esse período, 1.500-2.000 unidades/dia foram administradas por 24 semanas. Escores da margem palpebral, escores de expressibilidade da glândula meibomiana, classificação de Oxford, teste de Schirmer I, tempo de ruptura lacrimal, osmolaridade da lágrima e escore do Índice de Doenças da Superfície Ocular foram avaliados no início e após 8, 12 e 24 semanas. Resultados: O escore de expressibilidade da glândula meibomiana, Schirmer I, tempo de ruptura lacrimal, osmolaridade da lágrima e o Índice de Doenças da Superfície Ocular apresentaram melhoras após 8 semanas de suplementação de vitamina D (p<0,05). Comparado com os valores do pré-tratamento, o escore da margem palpebral e a classificação de Oxford diminuíram na 12ª semana (p<0,05). Conclusão: A reposição de vitamina D parece melhorar a superfície ocular em indivíduos com deficiência de vitamina D.

Measurement and clinical implications of choroidal thickness in patients with inflammatory bowel disease / Determinação da espessura da coróide suas implicações clínicas em pacientes com doença inflamatória intestinal

ABSTRACTPurpose:Ocular inflammation is a frequent extraintestinal manifestation of inflammatory bowel disease (IBD) and may parallel disease activity. In this study, we evaluated the utility of a choroidal thickness measurement in assessing IBD activity.Methods:A total of 62 eyes of 31 patients with IBD [Crohn's disease (CD), n=10 and ulcerative colitis (UC), n=21] and 104 eyes of 52 healthy blood donors were included in this study. Choroidal thickness was measured using enhanced depth imaging optical coherence tomography. The Crohn's disease activity index (CDAI) and the modified Truelove Witts score were used to assess disease activity in CD and UC, respectively.Results:No significant differences in mean subfoveal, nasal 3000 μm, or temporal 3000 μm choroidal thickness measurements (P>0.05 for all) were observed between IBD patients and healthy controls. Age, smoking, CD site of involvement (ileal and ileocolonic involvement), CDAI, CD activity, and UC endoscopic activity index were all found to be significantly correlated with choroidal thickness by univariate analysis (P<0.05). Smoking (P<0.05) and the CD site of involvement (P<0.01) were the only independent parameters associated with increased choroidal thickness at all measurement locations.Conclusions:Choroidal thickness is not a useful marker of disease activity in patients with IBD but may be an indicator of ileal involvement in patients with CD.

RESUMOObjetivos:Inflamação ocular é uma manifestação extra-intestinal comum de doença inflamatória do intestino (IBD) e pode ser paralela a atividade da doença. Neste estudo, investigamos se a espessura da coroideia pode ser útil para avaliar a atividade da IBD.Método:Um total de 62 olhos de 31 pacientes com IBD [10 com doença de Crohn (CD) e 21 colite ulcerosa (UC)] além de 104 olhos de 52 doadores de sangue saudáveis foram incluídos neste estudo. A espessura da coróide foi medida utilizando-se imagens de tomografia de coerência óptica com profundidade aprimorada. O índice de atividade da doença Crohn (CDAI) e o índice de Truelove Witts modificado foram usados para avaliar atividade da doença em CD e UC, respectivamente.Resultados:Não houve diferença significativa entre os pacientes com IBD e controles saudáveis em termos de medições da espessura da coróide subfoveal média em região 3000 μm nasal e 3000 μm temporal (p>0,05). Com base na análise univariada; idade, tabagismo, local do envolvimento em CD (ileal ou íleo-cecal), CDAI, atividade CD e índice de atividade endoscópica da UC foram significativamente correlacionados com a espessura da coróide (p<0,05). No entanto, fumar (p<0,05) e o local de envolvimento em CD (p<0,01) foram os únicos parâmetros independentes associados com um aumento na espessura da coroideia em todos os pontos de medida.Conclusões:A espessura da coroide não é um marcador útil para refletir a atividade da doença em pacientes com IBD, mas pode ser um indicador de envolvimento ileal em pacientes com CD.