Hallazgos de microscopia confocal in vivo de la mucosa de la córnea y la lengua en pacientes con síndrome de Sjögren / In vivo confocal microscopy findings of cornea and tongue mucosa in patients with Sjögren's syndrome

Introducción y objetivos: Nuestro objetivo fue investigar si el síndrome de Sjögren (SS) tenía hallazgos distintivos en la microscopia confocal de la lengua de una manera no invasiva. Materiales y métodos: Este estudio retrospectivo de casos y controles evaluó los hallazgos de la microscopia confocal de córnea y lengua de los ojos derechos de 25 pacientes con ojo seco con deficiencia acuosa y 12 voluntarios sanos sin hallazgos de ojo seco. Hubo un total de 14 pacientes diagnosticados con ojo seco asociado a SS (SSDE), mientras que 11 casos fueron evaluados como ojo seco no Sjögren (NSDE). Resultados: Se observó una diferencia significativa en el recuento de células dendríticas a nivel del nervio subbasal corneal entre los grupos SSDE y NSDE (p=0,018). En el grupo SSDE, las imágenes de microscopia confocal de células inflamatorias dendritiformes hiperreflectantes en la mucosa de la lengua estaban a favor de la inflamación. Sin embargo, estos hallazgos no se encontraron en pacientes con NSDE o en controles. Conclusiones: Este estudio mostró que la microscopia confocal proporcionó una evaluación no invasiva de las células inflamatorias en la lengua de los pacientes con SS.(AU)

Introduction and objectives: We aimed to investigate whether Sjögren's syndrome (SS) had distinctive findings in tongue confocal microscopy in a non-invasive manner. Materials and methods: This retrospective case-control study evaluated corneal and tongue confocal microscopy findings of the right eyes of 25 patients with aqueous deficient dry eye and 12 healthy volunteers without dry eye findings. There were a total of 14 patients diagnosed with SS-associated dry eye (SSDE), while 11 cases were evaluated as non-Sjögren dry eye (NSDE). Results: A significant difference was observed in the dendritic cell count at the corneal subbasal nerve level between the SSDE and NSDE groups (P=.018). In SSDE group, the confocal microscopy images of dendritiform hyperreflective inflammatory cells in the tongue mucosa were in favor of inflammation. However, these findings were not found in patients with NSDE or in controls. Conclusions: This study showed that confocal microscopy provided a non-invasive evaluation of the inflammatory cells in the tongue of SS patients.(AU)

Traducción y validación del cuestionario Visual Function and Corneal Health Status (V-FUCHS) al idioma castellano / Translation and validation of the Visual Function and Corneal Health Status (V-FUCHS) questionnaire into Spanish language

Objetivo: Traducir y validar al castellano el cuestionario V-FUCHS en una población de pacientes que padecen distrofia endotelial de Fuchs (DEF).MétodosEl V-FUCHS consta de 15 preguntas, que valoran aspectos visuales de la calidad de vida en los pacientes con DEF, las cuales se pueden agrupar en 7 que valoran el factor «dificultad visual» y 8 que valoran el factor «deslumbramiento». Para la traducción y adaptación se siguieron las normas estandarizadas, destacando, una traducción, una retro-traducción y una aplicación en pacientes con DEF.ResultadosEn una primera fase se llegó al consenso de la traducción al castellano del V-FUCHS. Posteriormente, se incluyeron 25 pacientes para realizar la fase pre-test con el objetivo de valorar la aplicabilidad y la viabilidad del test. La puntuación de las mismas obtuvo un valor mínimo de −0,88 y un valor máximo de +2,44, según la escala probabilística de Rasch. El valor medio obtenido de las preguntas que conforman el factor dificultad visual fue de 0,61 (±0,71) y la media del factor deslumbramiento (Glare) fue de 0,41 (±0,51).ConclusiónLa validación del cuestionario V-FUCHS, tras su traducción y adaptación al castellano, demostró ser una herramienta útil para la valoración de la calidad visual de los pacientes con DEF. Los pacientes con un estado más avanzado de la enfermedad presentaron una mayor severidad en el resultado de la prueba. Asimismo, el factor deslumbramiento se correlaciona mejor con el aumento paquimétrico que con la agudeza visual del paciente. (AU)

Purpose: To translate and validate the V-FUCHS questionnaire into Spanish in a population of patients with Fuchs endothelial dystrophy (DEF).MethodsThe V-FUCHS consists of 15 short, easily understandable questions that assess visual aspects of quality of life in patients with DEF, which can be gathered into a group of seven that assess the “Visual Difficulty” factor and another group of eight that assess the “Glare Factor”. For the translation and cultural adaptation, the standardized norms for this process were followed, among other phases, a translation, a back-translation and an application in patients with DEF.ResultsIn the first phase, consensus was reached on the Spanish translation of the V-FUCHS. Subsequently, 25 patients were included to carry out the pre-test phase with the aim of assessing the applicability and feasibility of the test. The score obtained a minimum value of −0.88 and a maximum value of +2.44, according to the Rasch probabilistic scale. The mean value obtained from the Visual Difficulty factor was 0.61 (±0.71), while the mean for the Glare factor was 0.41 (±0.51).ConclusionThe validation of the V-FUCHS questionnaire, after its translation and adaptation into Spanish, proved to be a useful tool for assessing the visual quality of patients with DEF. Patients with a more advanced stage of the disease presented a greater severity in the test result. Likewise, the Glare factor (Glare) correlates better with the pachymetric increase than with the visual acuity of the patient. (AU)

Comparación fluorofotométrica de la administración de riboflavina en la cámara anterior mediante aplicación corneal e instilación en el fórnix / A fluorophotometric comparison of anterior chamber riboflavin delivery via corneal application and fornix instillation

Introducción y objetivos Investigamos si la autoadministración de riboflavina por parte de los pacientes podría ser una opción viable para el cross-linking corneal (CXL), teniendo en cuenta los importantes recursos necesarios para la impregnación de la córnea. Analizamos si administrar la riboflavina en el fórnix inferior (lugar de autoadministración) resulta en concentraciones de riboflavina no menores a cuando se aplica directamente en la córnea (zona de aplicación por personal médico). Pacientes y métodos Realizamos un estudio prospectivo para evaluar las concentraciones de riboflavina en seis puntos de tiempo (basal, cinco, 15, 30, 45 y 60 minutos) en 18 voluntarios para cada uno de los dos lugares de aplicación: córnea y fórnix. Las concentraciones de riboflavina (Peschke® TE 0,25%; Peschke Trade GmbH, Huenenberg, Suiza) en la cámara anterior fueron medidas por fluorofotometría (FluorotronTM Master FM-2; OcuMetrics Inc., Mountain View, CA, EE. UU.). Resultados En los dos lugares de aplicación, córnea y fórnix, se observó una autofluorescencia de 16,7 ng/mL (desviación estándar [DE] 5,5) y 14,6 ng/mL (DE 4,6) al inicio de la serie de mediciones (p = 0,221). Después de 30 minutos, las concentraciones de fluorescencia en la cámara anterior habían aumentado a 55,1 ng/mL (DE 25,5) y a 46,1 ng/mL (DE 25,1) (p = 0,293) sin un incremento relevante adicional a los 60 minutos. Conclusiones Este estudio encontró que la aplicación de gotas de riboflavina en el fórnix inferior no fue menor a la aplicación directa en la córnea, según las mediciones fluorométricas de las concentraciones de riboflavina en la cámara anterior. Sugiere que la autoadministración es viable en términos de impregnación corneal de riboflavina (AU)

Introduction and objectives We investigated whether riboflavin self-administration by patients could be a feasible option for corneal cross-linking, given the considerable resources required to impregnate the cornea with riboflavin. We analysed whether administering riboflavin in the inferior fornix (the site of self-administration) results in non-inferior riboflavin concentrations as when applied directly on the cornea (the site of administration by medical personnel). Patients and methods We conducted a prospective study to evaluate riboflavin concentrations at six time-points (baseline, 5, 15, 30, 45 and 60min) in 18 healthy volunteers for each of two application sites: cornea and fornix. Anterior chamber riboflavin (Peschke® TE 0.25%) concentrations were measured by fluorophotometry (Fluorotron™ Master FM-2). Results For the two application sites cornea and fornix, participants did not differ in terms of age and sex. At baseline, the autofluorescence in the anterior chamber was 16.7ng/ml (SD 5.5) and 14.6ng/ml (SD 4.6) (p=0.221). After 30min, anterior chamber fluorescein concentrations had risen to 55.1ng/ml (SD 25.5) and 46.1ng/ml (SD 25.1) (p=0.293) without a further relevant increase by 60min. Conclusions This study found that applying riboflavin drops in the inferior fornix was non-inferior to applying it directly to the cornea, based on fluorophotometric measurements of anterior chamber riboflavin concentrations. This suggests that self-application of riboflavin is feasible in terms of corneal riboflavin impregnation (AU)

A lower birth weight percentile is associated with central corneal thickness thinning: Results from the Gutenberg Prematurity Eye Study (GPES)

Purpose: Prematurity, prenatal growth restriction, and retinopathy of prematurity (ROP) are associated with altered ocular geometry, such as a steeper corneal shape in childhood, but it is unclear whether perinatal history affects corneal thickness development, so this study investigated whether corneal thickness in adulthood is affected by perinatal history. Marterials and Methods: The Gutenberg Prematurity Eye Study (GPES) is a retrospective cohort study with a prospective ophthalmologic examination in Germany. The corneal thickness was measured by Scheimpflug imaging (Pentacam HR, Oculus Optikgeräte GmbH, Wetzlar, Germany), and the relationship between perinatal parameters respective birth weight percentile and corneal thickness at different locations was assessed using uni- and multivariable linear regression models. Covariates included age, sex, mean corneal radius, white-to-white distance, gestational age, birth weight percentile, ROP occurrence, and treatment. The main outcome measures were corneal thickness at the apex, the pupil center, and the corneal periphery. Results: The corneal thickness was measured in 390 participants (754 eyes, mean age 29.7+/-8.7 years, 224 females). In multivariable analyses, a lower birth weight percentile was associated with a lower corneal thickness at the apex (B = 0.20, p = 0.003) and the pupil (B = 0.19, p = 0.007). These effects diminished towards the corneal periphery and were not observed beyond the 4-mm diameter circle around the thinnest corneal position. Neither gestational age, ROP occurrence, or ROP treatment affected the corneal thickness. Conclusion: A lower birth weight percentile in subjects born preterm as a proxy for restricted fetal growth is associated with corneal thickness thinning in adults aged 18 to 52 years, indicating that corneal thickness development, particularly in the corneal center, may originate in the fetal stage. (AU)

Pierre Robin sequence and keratoconus, a rare association / Síndrome de Pierre Robin y quearotocono, una rara asociación

Pierre Robin sequence (PRS) is an inherited disorder that affects one in between 8,500 and14,000 people and is characterized by a triad of clinical signs. These include micrognathia,glossoptosis and obstruction of the upper airway, typically associated with palatal cleft.PRS has also been associated with various ocular complications, including high congenitalmyopia, congenital glaucoma, and retinal detachment.Because of the clinical importance of PRS, it is critical to illustrate the features of the Robinsequence to clearly define its primary and secondary clinical signs. We describe a patientwith PRS who developed keratoconus as a rare manifestation of the disease and its management. (AU)

La secuencia de Pierre Robin (PRS) es una patología hereditaria que afecta a una de entre8.500 y 14.000 personas y está caracterizada por una triada de signos. Estos incluyenmicrognatia, glosoptosis y obstrucción de vías aéreas altas, típicamente asociados a labioleporino.PRS ha sido también relacionado con afectación oftalmológica, incluyendo miopía congénita,glaucoma congénito o desprendimiento de retina.Debida a la importancia clínica de la PRS, es fundamental describir las distintascaracterísticas de la secuencia Pierre Robin, para así definir los signos principales ysecundarios de la patología. Describimos el caso de una paciente con PRS que desarrollóqueratocono como una extraña manifestación de la enfermedad. (AU)

Hypertension secondary to nitric oxide depletion produces oxidative imbalance and inflammatory/fibrotic outcomes in the cornea of C57BL/6 mice

Arterial hypertension (AH) leads to oxidative and inflammatory imbalance that contribute to fibrosis development in many target organs. Here, we aimed to highlight the harmful effects of severe AH in the cornea. Our experimental model was established by administration of NG-nitro-L-arginine-methyl-ester (L-NAME) to C57BL/6 mice, which were monitored weekly for arterial blood pressure and intraocular pressure (IOP). Morphological studies of ocular tissues were accompanied by analyses of reactive oxygen species generation, and localization/expression of NAPDH oxidase isoforms (NOX1, NOX2, NOX4) and inflammatory biomarkers (PPARα, PPARγ, IL-1β, IL-6, IL-10, TNF-α, and COX-2). Masson’s trichrome and Sirius Red staining were used to explore the fibrotic status of the cornea. The expression of collagen isoforms (COL1α1, COL1α2, COL3α1, COL4α1, COL4α2) and relevant metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) were also quantified to evaluate the participation of collagen metabolism in AH-related corneal damage. Hypertensive animals showed an increase in IOP values, and a thinner cornea compared with normotensive controls. Moreover, AH increased NADPH oxidase activity and reactive oxygen species generation in the cornea, which was accompanied by transcriptional upregulation of NOX isoforms and inflammatory biomarkers, while reducing PPAR expression. L-NAME-treated animals also developed corneal fibrosis with overexpression of collagen isoforms and reduction of factors responsible for collagen degradation. This is the first study reporting structural changes in the cornea and elevated IOP in L-NAME-treated mice. Overexpression of the NADPH oxidase system and collagen deposition might play a substantial role in the pathogenic mechanisms contributing to ocular disturbances in a context of severe hypertension. (AU)

Estabilidad del colirio de insulina para el tratamiento de úlceras corneales refractarias / Stability of insulin eye drops in the treatment of refractory corneal ulcers

Objetivo: Determinar y comparar la estabilidad físico-química y microbiológica de dos colirios de insulina 25 UI/ml elaborados con suerofisiológico o balanced salt solution bajo diferentes condiciones de conservación durante 120 días.Método: Los colirios se elaboraron por triplicado con insulina Actrapid®100 Ul/ml y balanced salt solution o suero fisiológico como vehículo, yfueron conservados a temperatura ambiente (25 °C), en nevera (2-8 °C)o congelador (–20 °C) durante 120 días. Se determinó la concentraciónde insulina mediante cromatografía liquida de ultra alta resolución, laosmolalidad y el pH a días 0, 3, 7, 15, 30, 60, 90 y 120. Asimismo, seextrajeron muestras para estudios microbiológicos en los días 0, 15, 30,60, 90 y 120.Resultados: La formulación elaborada con suero fisiológico mantuvola concentración de insulina por encima del 90% con respecto a la inicialtras 120 días de estudio en todas las condiciones de temperatura. En elcaso del colirio elaborado con balanced salt solution, la concentraciónse mantuvo estable en ambiente y congelador tras 120 días, aunque ennevera descendió por debajo del 90% a día 90 de estudio. Los valoresde osmolalidad y pH se mantuvieron constantes en ambas formulacionesy condiciones de conservación. No se observó crecimiento microbiológico en ninguna de las muestras retiradas.Conclusiones: El colirio de insulina 25 UI/ml elaborado con suerofisiológico es estable 120 días, conservado tanto a temperatura ambientecomo en nevera o congelador, protegido de la luz. Con balanced saltsolution permanece estable 120 días a temperatura ambiente y congelador, reduciéndose el periodo de validez a 90 días en el caso de laconservación en nevera. (AU)

Objective: To determine and compare the physicochemical and microbiological stability of two 25 IU/mL insulin eye drop formulations madewith normal saline and a balanced salt solution, respectively, stored for120 days under various conditions.Method: Eye drops were compounded in triplicate with 100 IU/mLActrapid® insulin and either normal saline or a balanced salt solution asvehicles, and they were stored alternatively at room temperature (25 °C),in a refrigerator (2-8 °C) or in a freezer (–20 °C) for 120 days. Insulinconcentrations were determined by ultra-high resolution liquid chromatography, and osmolality and pH values were measured at days 0, 3, 7,15, 30, 60, 90 and 120. Likewise, samples were extracted for microbiological studies on days 0, 30, 60, 90 and 120.Results: The formulation made with normal saline maintained insulinconcentrations above 90% of the baseline level after 120 days acrossall temperature conditions. In the case of the balanced salt solution-basedeye drops, insulin concentration when stored at room temperature or inthe freezer remained stable after 120 days, although insulin concentrationwhen stored in the refrigerator fell below 90% on day 90 of the study.Osmolality and pH values remained constant in both formulations andacross all storage conditions. No microbiological growth was observedin any of the samples. Conclusions: 25 IU/mL insulin eye drops made with normal salineremain stable for 120 days whether they are stored at room temperature,in a refrigerator or in a freezer, provided that they are protected fromlight. When made with a balanced salt solution, they remain stable for120 days at room temperature and in a freezer, their shelf life being reduced to 90 days in the case of storage in a refrigerator. (AU)

The role of peripheral ocular length and peripheral corneal radius of curvature in determining refractive error

Purpose: The purpose of this study was to extend the knowledge of peripheral biometric component and its relationship to refractive status in healthy individuals by determining the correlation between peripheral ocular length to peripheral corneal radius ratio and the refractive error.Methods: This prospective study was conducted on thirty-three healthy adult participants. Refractive error was assessed objectively and subjectively and recorded as the mean spherical equivalent. Central and peripheral ocular lengths at 30° were assessed using partial coherence interferometry under dilation with 1% tropicamide. Central and peripheral corneal radius of curvature was assessed using Scheimpflug topography. Peripheral ocular lengths at 30° were paired with peripheral corneal curvatures at the incident points of the IOLMaster beam (3.8mm away from corneal apex) superiorly, inferiorly, temporally and nasally to calculate the peripheral ocular length-peripheral corneal radius ratio. Descriptive statistics were used to describe the distribution and spread of the data. Pearson’s correlation analysis was used to present the association between biometric and refractive variables.Results: Refractive error was negatively correlated with the axial length-central corneal radius ratio (r=−0.91; p<0.001) and with 30° peripheral ocular length-peripheral corneal radius ratio in all four meridians (r≤−0.76; p<0.001). The strength of the correlation was considerably lower when only axial length or peripheral ocular lengths were used.Conclusion: Using the ratios of peripheral ocular length-peripheral corneal radius to predict refractive error is more effective than using peripheral corneal radius or peripheral ocular length alone. (AU)

A refined model on flow and oxygen consumption in the human cornea depending on the oxygen tension at the interface cornea/post lens tear film during contact lens wear

The study of oxygen consumption rate under” in vivo” human cornea during contact lens wear has been technically a challenge and several attempts have been made in the last 20 years to model the physiology of the human cornea during contact lens wear. Unfortunately, some of these models, based on a constant corneal oxygen consumption rate, produce areas on the cornea where the oxygen tension is negative, which has no physical sense. In order to avoid such inconsistency, different researchers have developed alternative models of oxygen consumption, which predict the likely oxygen metrics available at the interface cornea/post lens tear film by determination of oxygen flux, oxygen consumption, and oxygen tension through the different layers (endothelium, stroma, and epithelium). Although oxygen deficiency produces corneal edema, corneal swelling, hypoxia, acidosis, and other abnormalities, the estimation of the oxygen distribution below the impact of a contact lens wear is interesting to know which lens transmissibility was adequate to maintain the cornea and avoid epithelial and stromal anoxia. The estimation of minimum transmissibility for a lens for extended wear applications will be very useful for both clinicians and manufacturers. The aim of this work is to present a complete discussion based on Monod kinetics model that permits give an estimation of oxygen partial pressure distribution, the profile distribution of corneal flux and oxygen consumption rate, and finally the estimation of the relaxation mechanism of the cornea depending on the oxygen tension at the interface cornea/post lens tear film. Relaxation time in this context can quantify the capability of the corneal tissue to adapt to increasing concentrations of oxygen. It is proposed this parameter as a biological meaningful indicator of the interaction between contact lens polymers and living tissues such as the corneal cellular layer. (AU)

Manejo del tratamiento de úlcera corneal perforada secundaria a una infección fúngica / Management of corneal ulcer treatment secondary to fungal infection

La córnea es la membrana transparente en forma de disco abombado, que constituye la parte anterior del globo ocular y se halla delante del iris. La infecciones de este tejido son muy comunes y pueden llegar a producir ulceras. Un tratamiento retardado o inadecuado puede dar lugar a complicaciones, una de estas puede ser la perforación corneal. (AU)

The cornea is the transparent membrane in the form of a bulging disc, which forms the front part of the eyeball and is located in front of the iris. Infections of this tissue are very common and can lead to ulcers. Delayed or inadequate treatment can lead to complications, one of which can be corneal perforation. (AU)

Refractive characteristics of keratoconus eyes with corneal Vogt's striae: A contralateral eye study

Purpose: The aim of this study was to assess and compare clinical characteristics of bilateral keratoconus patients with unilateral Vogt's striae.MethodsIn this contralateral eye study, refractive status were evaluated in patients with bilateral keratoconus whose corneas had definite slit-lamp biomicroscopic evidence of unilateral Vogt's striae. All cases underwent a comprehensive ophthalmic examination. Some refractive errors components provided by autorefraction were converted to vectorial notation for power vector analysis. Finally, the outcomes were compared between keratoconus eyes with and without Vogt's striae.ResultsFifty patients aged 20 to 38 years (27.43±5.5) were recruited in this study. The results showed a significant difference in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), non-cycloplegic and cycloplegic autorefraction including sphere, cylinder, spherical equivalent, and J0, between keratoconus eyes with and without Vogt's striae (all P<0.05), except for J45 (P=0.518 in non-cycloplegic autorefraction and P=0.574 in cycloplegic autorefraction). Comparison of cycloplegic and non-cycloplegic autorefraction in both study groups showed significant differences in the sphere and spherical equivalent (all P<0.001), but no significant difference was found in cylinder, J0, and J45 between the study groups (all P>0.05).ConclusionsComparison of the cycloplegic and non-cycloplegic autorefraction in keratoconus eyes with and without Vogt's striae showed significant differences in UDVA, CDVA, and some refractive errors components provided by autorefraction between the two groups, with a worse condition in KCN eyes with Vogt's striae. (AU)

Impact of contact lens wear on epithelial alterations in keratoconus

PURPOSE: The purpose of this study was to characterize the central epithelial thickness (CET) of penetrating keratoplasty corneal specimens obtained from patients with keratoconus (KC) and correlate the histological patterns with their clinical history. METHODS: Ex vivo histological imaging was performed to measure CET and total corneal thickness (TCT) in 56 patients with KC. Microscopic slides from penetrating keratoplasty corneal specimens, stained with hematoxylin and eosin were evaluated using bright field microscopy. CET and TCT were measured, and morphological features were studied. Clinical history regarding duration of KC prior to surgery and length of and tolerance to contact lens wear were compared and analyzed. RESULTS: The microscopic slides of all patients available for follow up (n = 48) were analyzed and CET and TCT were measured. The histological evaluation revealed 3 distinctive epithelial patterns. Pattern 1 with central hypertrophic and hydropic changes (n = 19) measured 70.89 ± 25.88 Mum in CET and 308.63 ± 100.74 Mum in TCT; Pattern 2 (n = 14) had not changed, similar to normal epithelium CET and TCT measuring 36.5 ± 7.02 Mum and 260.14 ± 87.93 Mum respectively. Pattern 3 (n = 15) demonstrated thinner central epithelium characterized by atrophy and focal hydropic changes measuring 19.93 ± 4.60 Mum and 268.00 ± 79.39 Mum in CET and TCT respectively (all p < 0.0001). The presence of Pattern 2 characterized by similar to normal CET was correlated with the duration of the condition (R = 0.600, p = 0.030). There was a significant difference in the length of CL wear comparing those with patterns 1 and 2 versus 3 (least no. of CL years) (p = 0.05 and p = 0.33 respectivelly). CONCLUSIONS: Patients with advanced disease have various central corneal epithelial changes detected with histology. Although each central epithelial pattern type was distinctive comparing the 3 patterns, there was no correlation with years of CL wear but only with the duration of the condition

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Consecuencia de la hipoxia corneal profunda crónica / Consequences of chronic deep corneal hypoxia

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Grosor epitelial corneal un año después de la cirugía de LASIK miópico, medido mediante tomografía de coherencia óptica de segmento anterior combinado con disco de Plácido / Corneal epithelial thickness one year after myopic LASIK surgery, measured by anterior segment optical coherence tomography combined with Placido disk

OBJETIVO: Comparar el grosor epitelial corneal (GEC) en pacientes intervenidos de LASIK miópico de más de un año respecto a sujetos no operados. MÉTODOS: En este estudio retrospectivo observacional se incluyeron 93 sujetos no operados (186 ojos) y 26 sujetos (52 ojos) operados de LASIK miópico. Se realizó una tomografía óptica de segmento anterior (OCT-SA) combinada con anillo de Plácido en todos los sujetos y se midió el GEC por sectores. Se hizo análisis estadístico para determinar diferencias entre las variables medidas en ambos grupos, así como análisis multivariante para buscar predictores de GEC. RESULTADOS: No hubo diferencias significativas entre los grupos en términos demográficos (edad, sexo) ni de segmento anterior (equivalente esférico, paquimetría) (todas las p > 0,05). Se obtuvieron diferencias estadísticamente significativas (p < 0,05) entre los dos grupos en todos los sectores estudiados, central, anillos interno y externo, siendo mayores todos los valores de GEC en los pacientes intervenidos de LASIK ≥ 1 año. A excepción del tiempo transcurrido desde la cirugía (p = 0,00), no se encontró correlación entre el GEC y la edad, el sexo, las dioptrías ablacionadas ni otra variable estudiada (p > 0,05). CONCLUSIONES: El GEC medio y por sectores medido mediante la OCT-SA es mayor en pacientes intervenidos de LASIK hace más de un año. La única variable correlacionada con el GEC tras el LASIK es el tiempo desde la cirugía. Las modificaciones del GEC deben ser tenidas en cuenta al planear la cirugía refractiva por sus implicaciones en el resultado final

OBJECTIVE: To compare corneal epithelial thickness (CET) between patients who underwent LASIK surgery for the correction of myopia at least one year ago and healthy subjects. METHODS: A retrospective observational study was conducted that included 93 healthy subjects (186 eyes) and 26 subjects (52 eyes) that underwent myopic LASIK surgery. OCT-SA, combined with Placido disk, was performed on all subjects, and CET maps were measured. Statistical analysis was performed to analyse differences between groups. Multivariate analysis was also performed to look for possible predictors of final CET. RESULTS: There was no statistically significant differences between the groups in the demographic (age, sex) or anterior segment parameters (spherical equivalent, pachymetry) (all P > .05). Statistically significant differences (P < .05) were obtained between both groups when comparing CET, including central, internal, and external rings (higher in patients that underwent LASIK surgery ≥1 year). With the exception of the time elapsed since surgery (P = .00), no correlation was found between the CET and age, sex, ablated dioptres, or other variables studied (P < .05). CONCLUSIONS: CET values measured by the OCT-SA were higher in patients that underwent LASIK surgery ≥ 1 year. The only variable that correlated with the CET after LASIK was the time elapsed since surgery. CET changes should be taken into consideration when planning refractive surgery due to its implications on the final outcome

The microanatomy of Bowman's layer in the cornea of the pig: Changes in collagen fibril architecture at the corneoscleral limbus

In most animals, Bowman's layer is a feature of the cornea of the eye, and lies between the sur-face epithelium and the stromal extracellular matrix that makes up the bulk of the cornea. It is comprised of a condensation of disorganised collagen fibrils. However, it has been conjectured that not all species possess Bowman’s layer, and pigs are a species that has classically been stated to lack this anatomical structure, although there is disagreement in the published literature. Here, we studied the porcine cornea using transmission and scanning electron microscopy (TEM and SEM) to ascertain whether Bowman’s layer existed. TEM identified a thin band of disorganised collagen fibrils between the epithelial basement membrane and corneal stroma. SEM images of the central and peripheral corneal surfaces, following removal of the corneal epithelium by cell maceration, revealed a disorganised meshwork of collagen fibrils, with a highly aligned annulus of collagen at the limbus. In between the peripheral cornea and limbus, a "transition zone" is observed where collagenfibrils start to align. Quantification of fibril alignment demonstrates a significant increase in collagen alignment from 0.08 ± 0.04 to 0.33 ± 0.07 (p < 0.001; n = 60; 0 = no alignment, 1 = full alignment) with increasing distance from the corneal centre. These data together lead us to conclude that the porcine cornea does include Bowman's layer, though it is thin (contributing roughly 0.2% of corneal thickness), and thus, reaffirms the porcine cornea's similarity to its human counterpart and usefulness as a model system

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Complicaciones asociadas al uso de lentes de contacto blandas / Complications associated with the use of soft contact lenses

Las lentes de contacto blandas son una buena alternativa al uso de gafas para la corrección de defectos refractivos. Sin embargo, un mal uso puede asociarse a complicaciones. La manipulación incorrecta, la mala higiene o el sobreuso de dichas lentes pueden producir mala tolerancia, inflamación ocular e incluso secuelas visuales. En esta revisión se describen las complicaciones más frecuentes, y también las más graves, de tipo infeccioso y no infeccioso asociadas al uso de lentes de contacto blandas, así como las recomendaciones para su correcto uso

Soft contact lenses are a good alternative to the use of glasses for the correction of refractive defects. However, improper use can be associated with complications. Incorrect handling, poor hygiene, or over-use of the lenses can lead to poor tolerance, eye inflammation, and even visions sequelae. In this review, the most common and also the most serious are described, including the infectious and non-infectious complications associated with the use of soft contact lenses, including recommendations for their correct use

Megalocórnea esencial: relato de caso / Primary megalocornea: Case report

El neonato tiene un diámetro horizontal de la córnea, generalmente de hasta 10 mm, con un crecimiento de hasta 2 mm en los primeros 2 años de vida. Presentamos un caso de megalocórnea, un trastorno raro, recesivo, ligado al cromosoma X, en un niño de 3 meses de edad, buscando revisar lo que la literatura médica aporta como información sobre la enfermedad, así como los parámetros diagnósticos y de seguimiento de sus principales diagnósticos diferenciales

The neonate has a horizontal diameter of the cornea, usually up to 10 mm with growth up to 2 mm in the first 2 years of life. We report a case of megalocornea, a rare, recessive, X-linked disorder in a 3-month-old child, seeking to review what the medical literature brings information about the condition, as well as diagnostic and follow-up parameters, of its main differential diagnoses

Agreement between Pentacam and handheld Auto-Refractor/Keratometer for keratometry measurement / Concordancia entre el sistema Pentacam y un auto-refractómetro/queratómetro portátil para la medición de queratometría

OBJECTIVE: This study was conducted to evaluate the level of agreement in keratometry measurements between a rotating Scheimpflug imaging-based system (Pentacam) and a handheld auto-refractokeratometer (handheld NIDEK ARK-30). METHOD: This analytical cross-sectional study was conducted in the right eyes of 579 subjects. Keratometry measurements were conducted with the Pentacam and the handheld NIDEK ARK-30 systems. The SPSS Software version 22 and MedCalc V3 were applied to estimate descriptive statistics using paired t-test, Pearson correlation coefficient, 95% limits of agreement (LoA), and Bland-Altman plot. RESULTS: In the total sample, the inter-device difference in the mean flat and steep keratometry values was -0.266 diopter (D) (P-value < 0.001) and 0.052 D (P-value = 0.093), respectively. There was a significant difference in mean flat keratometry between the two devices in all groups of refractive errors (paired difference < 0.5 D and P-value < 0.001). The difference in mean steep keratometry was significant only in myopic subjects (P-value = 0.046). The 95% LoA between the two devices measurements was 2.51 D, 3.98 D, and 6.37 D for flat keratometry and 2.6 D, 3.2 D, and 3.9 D for steep keratometry in emmetropic, myopic, and hyperopic subjects, respectively. CONCLUSION: Our study showed relatively wide limits of agreement between handheld NIDEK ARK-30 and Pentacam; therefore, these devices cannot be used interchangeably for measuring corneal curvature

OBJETIVO: Se realizó este estudio para evaluar el nivel de concordancia de las mediciones queratométricas obtenidas mediante un sistema de cámara rotatoria Scheimpflug (Pentacam) y un auto-refractoqueratómetro portátil (NIDEK ARK-30 portátil). MÉTODO: Este estudio analítico transversal fue realizado en los ojos derechos de 579 sujetos. Las mediciones queratométricas se obtuvieron con Pentacam y NIDEK ARK-30 portátil. Se aplicó el software SPSS versión 22 y MedCalc V3 para calcular las estadísticas descriptivas utilizando la prueba t pareada, el coeficiente de correlación de Pearson, los límites de concordancia (LoA) al 95%, y el análisis gráfico de Bland-Altman. RESULTADOS: En la muestra total, la diferencia inter-dispositivo en cuanto a valores queratométricos planos y curvos medios fue de -0,266 dioptrías (D) (valor P < 0,001) y 0,052 D (valor P = 0,093), respectivamente. Se produjo una diferencia significativa en términos de queratometría plana media entre los dos dispositivos para todos los grupos de errores refractivos (diferencia pareada < 0,5 D y valor P < 0,001). La diferencia en cuanto a queratometría curva media fue significativa únicamente en sujetos miopes (valor P = 0,046). Los LoA al 95% entre las mediciones de los dos dispositivos fue de 2,51 D, 3,98 D, y 6,37 D para la queratometría plana, y de 2,6 D, 3,2 D, y 3,9 D para la curva, en los sujetos con emetropía, miopía e hipermetropía, respectivamente. CONCLUSIÓN: Nuestro estudio reflejó unos límites de concordancia relativamente amplios entre NIDEK ARK-30 portátil y Pentacam; por tanto, estos dispositivos no pueden utilizarse indistintamente para medir la curvatura de la córnea

Corneo-pterygium total area measurements utilising image analysis method / Mediciones del área total de pterigium corneal utilizando un método de análisis de imagen

PURPOSE: To describe an objective method to accurately quantify corneo-pterygium total area (CPTA) by utilising image analysis method and to evaluate its association with corneal astigmatism (CA). METHODS: 120 primary pterygium participants were selected from patients who visited an ophthalmology clinic. We adopted image analysis software in calculating the size of invading pterygium to the cornea. The marking of the calculated area was done manually, and the total area size was measured in pixel. The computed area is defined as the area from the apex of pterygium to the limbal-corneal border. Then, from the pixel, it was transformed into a percentage (%), which represents the CPTA relative to the entire corneal surface area. Intra- and inter-observer reliability testing were performed by repeating the tracing process twice with a different sequence of images at least one (1) month apart. Intraclass correlation (ICC) and scatter plot were used to describe the reliability of measurement. RESULTS: The overall mean (N = 120) of CPTA was 45.26 ± 13.51% (CI: 42.38-48.36). Reliability for region of interest (ROI) demarcation of CPTA were excellent with intra and inter-agreement of 0.995 (95% CI, 0.994-0.998; P < 0.001) and 0.994 (95% CI, 0.992-0.997; P < 0.001) respectively. The new method was positively associated with corneal astigmatism (P < 0.01). This method was able to predict 37% of the variance in CA compared to 21% using standard method. CONCLUSIONS: Image analysis method is useful, reliable and practical in the clinical setting to objectively quantify actual pterygium size, shapes and its effects on the anterior corneal curvature

OBJETIVO: Describir un método objetivo para cuantificar con precisión el área total corneal invadida por pterigium (CPTA) utilizando un método de análisis de imagen evaluando su asociación con el astigmatismo de la córnea (AC). MÉTODOS: Se seleccionaron 120 participantes con pterigium primario de entre los pacientes que acudieron a la clínica oftalmológica. Utilizamos un software de análisis de imagen para calcular el tamaño del pterigión invasivo hacia la córnea. La marcación del área calculada se realizó manualmente, midiéndose en píxeles el tamaño del área total. El área computada se define como el área desde el ápex del pterigium al borde del limbo corneal. A continuación, a partir del análisis de pixels, se transformó en un porcentaje (%), que representa el CPTA relativo al área total de la superficie de la córnea. Se realizaron pruebas de fiabilidad Intra- e inter-observador mediante un proceso, de doble repetición, con una secuencia de imágenes diferente, con separación de un (1) mes como mínimo. Se utilizaron la correlación intra-clase (ICC) y el gráfico de dispersión para describir la fiabilidad de las mediciones. RESULTADOS: La media global (N = 120) de CPTA fue 45,26 ± 13,51% (IC: 42,38-48,36). La fiabilidad para la demarcación de la región de interés (ROI) de CPTA fue excelente con intra e inter-acuerdo de 0,995 (95% IC, 0,994-0,998; P < 0,001) y 0,994 (95% IC, 0,992-0,997; P < 0,001) respectivamente. El nuevo método se asoció positivamente al astigmatismo de la córnea (p < 0,01). Este método fue capaz de predecir el 37% de la varianza de AC, en comparación con el 21% utilizando el método estándar. CONCLUSIONES: El método de análisis de imagen descrito es útil, fiable y práctico en el entorno clínico, para cuantificar objetivamente el tamaño real del pterigium, así como sus formas y efectos sobre la curvatura anterior de la córnea