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ABSTRACT Purpose: This study aimed to analyze variations in intraoperative corneal thickness during corneal cross-linking in patients with keratoconus and to investigate its possible correlation with presurgical maximal keratometry (Kmax) and pachymetry. Methods: This was a prospective case series. We used a method similar to the Dresden protocol, with the application of hydroxypropyl methylcellulose 0.1% hypo-osmolar riboflavin in corneas between 330 and 400 µm after epithelium removal. Corneal thickness was measured using portable calipers before and immediately after epithelium removal, and 30 and 60 min after the procedure. Results: The 30 patients in this study were followed up for one year. A statistically significant difference was observed in pachymetry values during the intraoperative period (p<0.0001) and an increase of 3.05 µm (95%C1: 0.56-5.54) for each diopter was seen after epithelium removal (p0.019). We found an average Kmax difference of —2.12 D between men and women (p0.013). One year after treatment, there was a statistically significant reduction in pachymetry (p<0.0001) and Kmax (p0.0170) values. Conclusions: A significant increase in pachymetry measurements was seen during the procedure, and most patients showed a regression in Kmax and pachymetry values one year after surgery.

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BACKGROUND: Recently a new surgical technique for intracorneal ring-segments (ICRS) assisted by femtosecond laser (FSL) called ByLimB was developed, involving the creation of the incision from a paralimbic region. This study aims to evaluate the safety and efficacy of the ByLimb technique following one year of follow-up. METHODS: A prospective, single-center study was conducted at the Zaldivar Institute in Buenos Aires, Argentina. Keratoconus patients with indication for ICRS-FSL assisted procedure, operated with the ByLimb technique were included. By using the ByLimb technique, the ICRS are placed without affecting the tunnel's roof, and the end of the ICRS is always away from the incision area. Visual acuity, topographic astigmatism, and the occurrence of complications were evaluated. Safety index was the main outcome and efficacy indes was a complimentary outcome. RESULTS: A total of 17 eyes completed the 12-month follow-up period. The safety index was 1.10 (mean postoperative corrected distance visual acuity (CDVA) in decimal: 0.76/preoperative CDVA: 0.69), while the efficacy index was 0.89 (mean postoperative uncorrected distance visual acuity UDVA in decimal: 0.62/preoperative CDVA: 0.69). Mean preoperative astigmatism was 5.3 ± 2.3, decreasing twelve months after surgery at 2.1 ± 1.2 (p < 0.001). No eye loss lines of vision and no intraoperative complications were observed. During the first month after surgery, an improper positioning of the ICRS based on topographic assessment was detected in five cases. A second procedure was performed, which consisted of opening the incision and introducing a Sinsky hook, through which the ICRS was mobilized and placed in its correct position. No incisional alterations, signs of infection, anterior segment anomalies, or fundus alterations were observed. CONCLUSION: FSL-assisted ICRS implantation through the perilimbal region has demonstrated an adequate safety index one year post-surgery. Additionally, this technique has facilitated accurate realignment of ICRS during secondary surgical interventions within one-month post-surgery. While the current findings are promising, continued follow-up of these cases is warranted.

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INTRODUCTION: The study aims to demonstrate and estimate the prevalence of clinical corneal ectasia and keratoconus (KC) in patients with relatively low keratometry (low-K KC). METHODS: In a retrospective, analytical, and non-interventionist study, one eye was randomly selected from 1054 patients from the original Tomographic Biomechanical Index (TBIv1) study and the external validation (from Rio de Janeiro, Brazil, and Milan, Italy clinics). Patients were stratified into three groups. Group 1 included 736 normal patients, and groups 2 and 3 included 318 patients with clinical KC in both eyes, divided into low-K KC (90 patients) and high-K KC (228 patients), respectively. All patients underwent a comprehensive ophthalmological evaluation along with Pentacam and Corvis ST (Oculus, Wetzlar, Germany) examinations. Cases with maximum mean zone 3 mm keratometry (Kmax zone mean 3 mm) lower than 47.6 diopters (D) were considered as low-keratometry keratoconus, and cases with Kmax zone mean 3 mm higher than 47.6 D were regarded as high-keratometry keratoconus. RESULTS: Ninety (28.30%) of the 318 KC group presented ectasia with low-keratometric values (low-Kmax). The average age in the normal group was 39.28 years (range 6.99-90.12), in the low-Kmax KC group it was 37.49 (range 13.35-78.45), and in the high-Kmax KC group it was 34.22 years (range 12.7-80.34). Mean and SD values and median (range), respectively, of some corneal tomographic and biomechanical parameters evaluated from the low-Kmax KC group were as follows: Belin-Ambrósio enhanced ectasia display (BAD-D) 3.79 ± 1.62 and 3.66 (0.83-9.73); Pentacam random forest index (PRFI) 0.78 ± 0.25 and 0.91 (0.05-1); corneal biomechanical index (CBI) 0.58 ± 0.43 and 0.75 (0-1); TBI 0.93 ± 0.17 and 1 (0.35-1); and stiffness parameter at A1 (SP-A1) 86.16 ± 19.62 and 86.05 (42.94-141.66). CONCLUSION: Relatively low keratometry, with a Kmax lower than 47.6 D, can occur in up to 28.30% of clinical keratoconus. These cases have a less severe presentation of the disease. Future studies involving larger populations and prospective designs are necessary to confirm the prevalence of keratoconus with low keratometry and define prognostic factors in such cases.

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Introducción: Globalmente, existe un aumento de la prevalencia del queratocono y su diagnóstico en edades tempranas. Se notifican un gran número de casos subclínicos y otros con una rápida progresión, condicionada por el inicio precoz de la enfermedad y la asociación a factores de riesgo. Objetivo: Describir los aspectos epidemiológicos, clínicos y el resultado de los medios de diagnóstico implicados en la detección precoz del queratocono infantil. Desarrollo: En niños con ametropía hay elementos que alertan la presencia de un queratocono como causa del defecto refractivo. Desde el punto de vista epidemiológico se encuentran: distribución geográfica, rol de la herencia y factores ambientales. Clínicamente se señalan los antecedentes de enfermedades, tales como las alergias, la presencia de miopía o astigmatismo miópico con inestabilidad refractiva y los signos clínicos relacionados con la progresión del cono. En los pacientes de riesgo es preciso realizar exámenes mediante diferentes medios de diagnóstico según su disponibilidad, siendo primordial el análisis refractivo, queratométrico y topográfico. Conclusiones: En la evaluación de los niños con ametropía se deben tener en cuenta elementos epidemiológicos y clínicos que permiten sospechar y diagnosticar precozmente el queratocono. En la interpretación de los resultados de los medios de diagnóstico involucrados en su detección, se deben considerar los hallazgos más frecuentes en la población infantil según el grado de progresión de la ectasia.

Introduction: Globally, there is an increase of the keratoconus prevalence and its diagnosis in early ages. A great number of subclinical cases and others with a quick progression are notified, conditioned by the early onset of the disease and the association with risk factors. Objective: To describe the epidemiological, clinical aspects and the result of diagnostic means involved in the early detection of infant keratoconus. Development: There are elements that alert the presence of a keratoconus as a cause of the refractive defect in children with ametropia. From the epidemiologic point of view they are: geographical distribution, heredity role and environmental factors. History of previous diseases are clinically pointed out, such as allergies, myopia or myopic astigmatism with refractive instability and the clinical signs related to cone progression. In risk patients it is necessary to carry out exams by means of different diagnostic means according to their availability, being essential the refractive, keratometric and topographic analysis. Conclusions: In the evaluation of children with ametropia, epidemiological and clinical elements should be taken into account that allow to suspect and early diagnose the keratoconus. In the interpretation of results of the diagnostic means involved in their detection the most frequent findings in the infant population, should be considered according to the ectasia degree of progression.

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PURPOSE: To compare the visual, refractive, and topographic outcomes of a high irradiance accelerated corneal crosslinking (ACXL) protocol after a 12-month follow-up between pediatric and adult patients with progressive keratoconus (KC). METHODS: Retrospective, comparative, cohort study. Patients with KC were divided into two groups: pediatric (≤ 18 years) and adult (> 18 years). All of them were managed with epi-OFF ACXL (30 mW/cm2, 8 min, pulsed 1:1 on and off = 7.2 J/cm2). Visual, refractive, and topographic values were measured preoperatively and at 1, 3, 6, and 12 months postoperative. KC progression, defined as a Kmax increase of ≥ 1D during follow-up, was recorded. RESULTS: Eighty-nine eyes (53 patients) were included for analysis; 45 (50.6%) eyes were from pediatric patients and 44 (49.4%) from adults. At one-year follow-up, pediatric patients experienced significantly higher rates of progression (22.2% vs. 4.5%, p = .014). Contrariwise, female gender (Beta = - 3.62, p = .018), a baseline uncorrected visual acuity of Snellen ≥ 20/60 (Beta = - 5.96, p = .007), and being ≥ 15 years at ACXL treatment (Beta = - 0.31, p = .021) were associated with non-progressive disease. A significant improvement in best-corrected visual acuity, Kmin, Km, and Kmax was recorded in both groups. Overall, 86.5% of eyes from both groups showed Kmax stabilization or improvement. CONCLUSIONS: Despite the similarity in visual, refractive, and topographic outcomes in both groups, younger age was associated with KC progression after ACXL at one year of follow-up.

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ABSTRACT Topography-guided ablation was designed to improve corneal regularity throughout the correction of corneal high order aberrations. The present report described three cases with different indications for topography-guided ablation to correct irregular astigmatism. The patients were monitored in the immediate and late postoperative periods to evaluate long-term corneal stabilization. Surgery indications were based on the patient's complaint of poor quality of vision associated with previous radial keratotomy, corneal transplant, or keratoconus. In all three cases, the patients reported an improvement in the quality of their vision and expressed satisfaction with the procedure; however, the patient who had previously been submitted to crosslinking presented with keratoconus progression in the late postoperative period. Finally, topography-guided customized ablation appears to represent a safe and effective technique for reducing corneal irregularities.

RESUMO A ablação guiada por topografia foi projetada para melhorar a regularidade da córnea durante a correção de aberrações de alta ordem da córnea. O presente relato descreveu três casos com diferentes indicações de ablação guiada por topografia para correção de astigmatismo irregular. Os pacientes foram monitorados no pós-operatório imediato e tardio para avaliar a estabilização corneana em longo prazo. As indicações cirúrgicas basearam-se na queixa do paciente de má qualidade de visão associada a ceratotomia radial prévia, transplante de córnea ou ceratocone. Nos três casos, os pacientes relataram melhora na qualidade da visão e manifestaram satisfação com o procedimento; entretanto, o paciente que já havia sido submetido ao crosslinking apresentou progressão do ceratocone no pós-operatório tardio. Finalmente, a ablação personalizada guiada por topografia parece representar uma técnica segura e eficaz para reduzir irregularidades da córnea em córneas não ectásicas.

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ABSTRACT Objective: To evaluate the long-term safety and efficacy of repeated corneal cross-linking in eyes of children and adolescents with progressive keratoconus. Methods: This retrospective study included nine eyes of nine consecutive patients with progressive keratoconus who underwent repeated corneal cross-linking 3.9 (range of 1.6 to 5.6) years after a primary one. All patients were followed for a mean period of 9.11 (range of 6 to 11) years after first treatment and 5.44 (range of 4 to 9) years, after corneal cross-linking retreatment. Results: Nine eyes of nine patients (six male) with progressive keratoconus underwent primary corneal cross-linking from 2009 to 2011. Despite the stability achieved with the epi-off corneal cross-linking, keratoconus continued to progress after some time. Mean time to documented evidence of keratoconus progression after primary corneal cross-linking was 3.9 (range of 1.6 to 5.6) years. All eyes were retreated as soon as progression was noted. At the last follow-up visit, 5.44 (range of 4 to 9) years after repeated corneal cross-linking, there was a significant decrease of 2.02 D in mean maximum topographic K-value (p = 0.045) and 1.95D in mean topographic K-value (p = 0.007). Conclusion: Repeated corneal cross-linking seems to be a safe and effective procedure to halt keratoconus progression after a primary corneal cross-linking failure.

RESUMO Objetivo: Avaliar a segurança e a eficácia a longo prazo da repetição do cross-linking corneano em olhos de crianças e adolescentes com ceratocone progressivo. Métodos: Estudo retrospectivo que incluiu nove olhos de nove pacientes consecutivos com ceratocone progressivo, que foram submetidos a retratamento com cross-linking corneano de 3,9 (variação de 1,6 a 5,6) anos após tratamento primário com cross-linking corneano. Todos os pacientes foram acompanhados por um período médio de 9,11 (variação de 6 a 11) anos após o primeiro tratamento e 5,44 (variação de 4 a 9) anos após retratamento com cross-linking corneano. Resultados: Nove olhos de nove pacientes (seis homens) com progressão do ceratocone foram submetidos a cross-linking corneano primário de 2009 a 2011. Apesar da estabilidade alcançada com o epi-off cross-linking corneano, o ceratocone continuou a progredir após algum tempo. O tempo médio para evidência documentada de progressão do ceratocone após cross-linking corneano primário foi de 3,9 (intervalo de 1,6 a 5,6) anos. Todos os olhos foram retratados com cross-linking corneano, assim que a progressão foi observada. Na última consulta de acompanhamento, 5,44 (variação de 4 a 9) anos após a repetição do cross-linking corneano, houve diminuição significativa de 2,02 D na média da curvatura máxima (p = 0,045) e 1,95 D na média da curvatura média (p = 0,007). Conclusão: O retratamento com cross-linking corneano parece ser um procedimento seguro e eficaz para interromper a progressão do ceratocone após falha primária do cross-linking corneano.

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ABSTRACT Purpose: To determine the absorbance coefficient of the thin porcine cornea to ultraviolet-A radiation (365 nm) submitted for crosslinking. Methods: This in vitro, benchtop experiment using cadaver tissue study analyzed 12 porcine corneal lamellas, which were obtained using a microkeratome after mechanical de-epithelization and separated into three thickness groups: 180, 300, and 360 μm. The corneal thickness values were measured by anterior-segment optical coherence tomography. All lamellas had ultraviolet-A (365 nm) absorbance measured with a 96-well plate spectrophotometer using an ultraviolet transparent microplate before riboflavin instillation and preand post-crosslinking according to the Dresden protocol. Results: The ultraviolet absorbance profiles of the 180, 300, and 360 μm groups were obtained as α-coefficients of 12.85, 76.55, and 120.27, respectively. A theoretical formula was calculated though a statistical analysis that demonstrated the correlation between stromal lamellar thickness and ultraviolet absorbance. Conclusions: Corneal thickness and ultraviolet-A spectral absorbance of corneal lamellas showed linear correlation. These findings can potentially contribute to the optimization of ultraviolet-A application during crosslinking, making the treatment of corneas with thickness <400 μm safe and personalized energy delivery for each corneal thickness.

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ABSTRACT Purpose: To determine normal corneal tomographic parameters in children and adolescents without corneal disease or atopy diagnosis. Methods: This descriptive cross-sectional study evaluated patients aged 8-16 years who underwent a complete slit-lamp biomicroscopic examination and tomographic corneal evaluation by a dual Scheimpflug analyzer, excluding those with ocular disease (including allergic conjunctivitis) or a positive prick test for systemic atopies. Results: A total of 170 patients were evaluated, and 34 patients (68 eyes) were analyzed once the exclusion criteria were applied. The sample's mean age was 10.76 ± 2.31 years; with 19 (55.9%) men and 15 (44.1%) women. The mean keratometry in the flat meridian (Kflat), steep meridian (Ksteep), and maximum (Kmax) were 42.37 ± 1.63D, 43.53 ± 1.65D, and 43.90 ± 1.73D, respectively. The mean values for corneal asphericity (ε2) and thinnest point were 0.28 ± 0.11 and 550.20 ± 37.90 μm, respectively. The inferior-superior asymmetry ratio (I-S) and coma were 0.74 ±0.59D and 0.28 ± 0.12D, respectively. Conclusion: The knowledge of normal corneal tomographic parameters and their variation in children and adolescents without corneal disease or atopy may be useful for diagnosing keratoconus and initiating early disease treatment.

RESUMO Objetivo: Identificar parâmetros tomográficos de normalidade em córneas de crianças e adolescentes sem a presença de atopias sistêmicas e alergias oculares. Métodos: Este estudo descritivo transversal avaliou pacientes com idade entre 8 e 16 anos que foram submetidos a exame biomicroscópico completo por lâmpada de fenda e avaliação tomográfica da córnea por tomógrafo dual Scheimpflug, excluindo pacientes com doença ocular (incluindo conjuntivite alérgica) ou prick test positivo para atopias sistêmicas. Resultados: Cento e setenta pacientes foram avaliados e após cumpridos os critérios de exclusão, 34 (68 olhos) foram analisados. A média etária da amostra foi 10,76 ± 2,31 anos; 19 (55,9%) eram meninos e 15 (44,1%) meninas. A média da ceratometria em dioptrias (D) no meridiano mais plano (Kflat), mais curvo (Ksteep) e máxima (Kmax) foram 42,37 ± 1,63D, 43,53 ± 1,65D e 43,90 ± 1,73D, respectivamente. Os valores médios da asfericidade corneana (ε2) e do ponto mais fino da córnea foram 0,28 ± 0,11 e 550,20 ± 37,90 micras (μm). A assimetria corneana inferior-superior (I-S) e coma foi em média 0,74 ± 0,59D e 0,28 ± 0,12D, respectivamente. Conclusão: O conhecimento dos valores médios e sua variação de parâmetros tomográficos da córnea em crianças e adolescentes sem atopias sistêmicas ou alergias oculares pode ser útil para o diagnóstico precoce do ceratocone e o seu tratamento em estágio inicial.

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ABSTRACT Keratoconus is a progressive disorder that manifests as a cone-like steepening of the central or paracentral inferior cornea and irregular stromal thinning. There is a gradual decrease in visual acuity due to corneal asymmetry, irregular astigmatism, and increased optical aberrations, consequently impacting the quality of life. Several procedures have been developed in an attempt to slow or reverse the progression. The Bader procedure, which includes a pattern of incisions around the circumference of the cornea and at the base of the protruding cone, is one such surgery. These incisions penetrate 70-90% of the cornea's depth. Its goal is to flatten the topography and reduce corneal asymmetry and irregular astigmatism. Though prior research found these to be highly promising, we report a patient who was given contact lenses to restore and maintain his vision while his corneal ectasia and thinning progressed over the following decade.

RESUMO O ceratocone é uma doença progressiva que se manifesta como uma elevação semelhante a um cone da cór­nea central ou paracentral inferior e é associada a uma re­dução irregular da espessura do estroma. Há uma diminuição gradual da acuidade visual devido à assimetria da córnea, ao astigmatismo irregular e a um aumento das aberrações ópticas, o que prejudica a qualidade de vida. Foram desenvolvidos vários procedimentos para tentar interromper ou mesmo reverter a evolução da doença. Um deles é o chamado procedimento de Bader, que inclui um padrão de incisões em volta da circunferência da córnea e na base do cone protuberante. Essas incisões penetram até 70%-90% da profundidade da córnea e têm o objetivo de achatar a topografia e diminuir a assimetria da córnea e o astigmatismo irregular. Embora essa técnica seja muito promissora, segundo um estudo anterior, aqui se apresenta o caso de um paciente no qual esses objetivos não foram atingidos. Esse paciente recebeu lentes de contato para restaurar e manter sua visão, enquanto sua ectasia corneana e a redução da espessura progrediram ao longo da década seguinte.

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ABSTRACT Purpose: To assess the outcomes of deep anterior lamellar keratoplasty or penetrating keratoplasty at the scar and the edema stages. Methods: Forty-five patients (45 eyes) with keratoconus scar stage (scar group, n=26; penetrating keratoplasty a subgroup, n=7; deep anterior lamellar keratoplasty b subgroup, n=19) and keratoconus edema stage (edema group, n=19; penetrating keratoplasty c subgroup, n=12; deep anterior lamellar keratoplasty d group, n=7) who received penetrating keratoplasty or deep anterior lamellar keratoplasty from 2000 to 2022 were retrospectively studied. At 1, 6, and 12 months after surgery, the best-corrected visual acuity, astigmatism, spherical equivalent, corneal endothelial cell density, and complications were analyzed. Results: The best-corrected visual acuity and average corneal endothelial cell loss rate were not significantly different between the scar and edema groups (p>0.05). At 6 and 12 months after surgery, the astigmatism and spherical equivalent in the scar group were significantly lower than those in the edema group (p<0.05). The spherical equivalent of the deep anterior lamellar keratoplasty b subgroup was lower than that of the penetrating keratoplasty a subgroup in the scar group 6 months after surgery (p<0.05). In the edema group, there was no significant difference in spherical equivalent between subgroups (p>0.05). There were no significant differences in best-corrected visual acuity and astigmatism between subgroups within the two groups (p>0.05). In comparison to the scar group, the edema group experienced more complications. According to a survival analysis, there was no statistically significant difference between the scar group and the edema group regarding the progression of vision. Conclusions: In terms of the outcomes and prognosis for vision after keratoplasty with edema stage and scar stage, deep anterior lamellar keratoplasty may be as effective as penetrating keratoplasty.

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El queratocono es una ectasia corneal bilateral asimétrica, en etapas iniciales no se evidencia la afectación binocular. El conocimiento del grado de asimetría en el queratocono pediátrico permite tomar decisiones oportunas en el manejo de los pacientes. Se realizó este trabajo con el objetivo de describir las características clínicas y el tratamiento de tres casos pediátricos con diferente grado de asimetría interocular del queratocono, atendidos en la consulta provincial de ectasias corneales pediátricas en Ciego de Ávila. Los pacientes mostraron diferencia entre ambos ojos de los signos clínicos, la refracción y las variables topográficas. Al paciente dos se le diagnosticó queratocono en un ojo, sin evidencias clínicas ni topográficas de la enfermedad en el ojo contralateral. Todos los pacientes mostraron astigmatismo miópico compuesto en ambos ojos y se les indicó corrección óptica. Al paciente uno se le corrigió con cristales, al dos con lentes de contacto rígidos de gas permeable y al tercero con piggyback en un ojo y lentes de contacto rígidos de gas permeable en el otro. Presentaron, además, una ambliopía asociada y se les orientó tratamiento oclusivo y tareas de visión cercana en los pacientes dos y tres. Es frecuente encontrar asimetría interocular en pacientes pediátricos con queratocono por la diferencia de progresión entre ambos ojos. El seguimiento periódico permite diagnosticar la enfermedad en el ojo contralateral en pacientes con diagnóstico de queratocono en un ojo, indicar una corrección óptica individualizada, sobre todo en presencia de anisometropía, y monitorizar la evolución de la ambliopía refractiva asociada con frecuencia(AU)

Keratoconus is an asymmetric bilateral corneal ectasia, in early stages binocular involvement is not evident. Knowledge of the degree of asymmetry in pediatric keratoconus allows timely decisions in patient management. This research was carried out with the objective of describing the clinical characteristics and the treatment of three pediatric cases with different degree of interocular asymmetry of keratoconus, treated in the provincial consultation of pediatric corneal ectasia in Ciego de Avila. Patients showed difference between both eyes in clinical signs, refraction and topographic variables. Patient two was diagnosed with keratoconus in one eye, with no clinical or topographic evidence of the disease in the contralateral eye. All patients showed compound myopic astigmatism in both eyes and optical correction was indicated. Patient one was corrected with glasses, patient two with rigid gas permeable contact lenses and patient three with piggyback in one eye and rigid gas permeable contact lenses in the other eye. They also presented an associated amblyopia and were directed occlusive treatment and near vision tasks in patients two and three. It is common to find interocular asymmetry in pediatric patients with keratoconus due to the difference in progression between the two eyes. Periodic follow-up makes it possible to diagnose the disease in the contralateral eye in patients diagnosed with keratoconus in one eye, to indicate individualized optical correction, especially in the presence of anisometropia, and to monitor the evolution of frequently associated refractive amblyopia(AU)

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El queratocono es una afección inflamatoria, es una ectasia corneal que se caracteriza por un aumento de la curvatura corneal. Se describe como una enfermedad progresiva y asimétrica asociada con cambios estructurales en la organización del colágeno corneal. Existen diferentes opciones terapéuticas con el objetivo de estabilizar la superficie corneal, mejorar la visión y evitar su progresión. El sistema piggyback consiste en adaptar un lente rígido de gas permeable con alta permeabilidad al oxígeno sobre un lente de contacto hidrofílico, es ideal para pacientes que requieren la óptica de un lente de contacto rígido, pero tienen dificultades con su material. Se indica cuando existe una intolerancia a los lentes rígidos de gas permeable, en córneas irregulares y con curvaturas avanzadas. Se presenta una paciente de 24 años de edad con diagnóstico de queratocono desde los 10 años de edad que se corregía con lente rígido de gas permeable. Acudió a consulta del servicio de córnea del Instituto Cubano de Oftalmología Ramón Pando Ferrer, en el año 2010 porque comenzó a presentar intolerancia a los lentes. Debido a que la paciente no presentaba criterio quirúrgico y tenía una agudeza visual mejor corregida con lentes de 1,0 en ambos ojos, se decidió realizar el tratamiento con piggyback corneal. Pese al seguimiento, como parte de la progresión de la enfermedad, a los 10 años de mantenerse con el piggyback, presentó un hidrops corneal agudo, el cual fue tratado. En la actualidad la paciente mantiene seguimiento anual por consulta, sin progresión del queratocono y sin complicaciones con el tratamiento de piggyback corneal(AU)

Keratoconus is an inflammatory condition, a corneal ectasia characterized by increased corneal curvature. It is described as a progressive and asymmetric disease associated with structural changes in the organization of corneal collagen. There are different therapeutic options to stabilize the corneal surface, improve vision and prevent progression. The piggyback system consists of fitting a rigid gas permeable lens with high oxygen permeability over a hydrophilic contact lens, it is ideal for patients who require the optics of a rigid contact lens, but have difficulties with its material. It is indicated when there is intolerance to rigid gas permeable lenses, in irregular corneas and with advanced curvatures. We present a 24-year-old female patient with a diagnosis of keratoconus since she was 10 years old, which was corrected with a rigid gas permeable lens. She went to the cornea service of the Cuban Institute of Ophthalmology Ramón Pando Ferrer, in 2010 because she began to present intolerance to lenses. Since the patient did not present surgical criteria and had a visual acuity better corrected with 1.0 lenses in both eyes, it was decided to perform corneal piggyback treatment. Despite the follow-up, as part of the progression of the disease, after 10 years of piggyback, she presented an acute corneal hydrops, which was treated. At present, the patient maintains annual follow-up via consultation, without progression of keratoconus and without complications with the corneal piggyback treatment(AU)

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ABSTRACT Purpose: This study aimed to examine the effects of unilateral corneal collagen cross-linking treatment on visual acuity and the topographic findings of the fellow untreated eye of patients who had bilateral progressive keratoconus. Methods: Patients with progressive keratoconus who underwent cross-linking treatment were screened retrospectively. A total of 188 untreated eyes of 188 patients whose eyes were treated unilaterally with either standard or accelerated cross-linking and refused cross-linking procedure for the fellow eye were included. Visual acuity and topographic findings of the fellow untreated eyes were obtained preoperatively and postoperatively at the 1st, 3rd, 6th, 12th, 24th, 30th, and 36th months. Results: The change over time of variables examined was similar in the untreated eyes of patients who received standard and accelerated cross-linking methods (p>0.05). At the 12th month, 136 (95.8%) untreated eyes were stable according to progression criteria. Only 4 (8%) eyes were progressive at the 24th month. No progression was observed in any of the 16 patients with a 36-month follow up. Conclusions: The results showed that the fellow untreated eyes of patients with bilateral progressive keratoconus did not have significant progression rates after unilateral cross-linking treatment.

RESUMO Objetivo: Examinar os efeitos do tratamento de reticulação unilateral do colágeno corneano na acuidade visual e os achados topográficos em olhos não tratados de pacientes com ceratocone progressivo bilateral. Métodos: Foram rastreados retrospectivamente pacientes com ceratocone progressivo submetidos a tratamento de reticulação. Foram incluídos no estudo 188 olhos não tratados de 188 pacientes tratado unilateralmente com reticulação padrão ou acelerada e que recusaram o procedimento de reticulação no outro olho. A acuidade visual e os achados topográficos dos olhos não tratados foram obtidos no pré- e pós-operatório no 1º, 3º, 6º, 12º, 24º, 30º e 36º mês. Resultados: As alterações ao longo do tempo foram semelhantes para as variáveis examinadas nos olhos não tratados de pacientes tratados com métodos de reticulação padrão e acelerado (p>0,05). No 12º mês, 136 olhos não tratados (95,8%) estavam estáveis, de acordo com os critérios de progressão. Apenas quatro olhos (8%) mostraram progressão no 24º mês. Nenhuma progressão foi observada nos 16 pacientes que tiveram um acompanhamento de 36 meses. Conclusões: O estudo mostrou que os olhos não tratados de pacientes com ceratocone progressivo bilateral não apresentaram taxas de progressão significativas após o tratamento unilateral com reticulação.

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ABSTRACT The occurrence of corneal ectasia after photorefractive keratectomy is a rare but serious complication of refractive surgery. Possible risk factors are not well assessed, but a probable reason is the failure to detect keratoconus preoperatively. In this report, we describe a case of corneal ectasia after photorefractive keratectomy in a patient who presented a suspicious tomography pattern preoperatively but had no degenerative alterations associated with pathologic keratoconus, as revealed by in vivo corneal confocal microscopy. We also review eligible case reports of post-photorefractive keratectomy ectasia to find similar characteristics.

RESUMO A ocorrência de ectasia corneana após ceratectomia fotorrefrativa é uma complicação rara, porém grave, em cirurgia refrativa. Os possíveis fatores de risco não são bem avaliados, mas a opinião atual é que a falha na detecção de ceratocone pré-operatório possa ser o principal motivo. Neste relato, descrevemos um caso de ectasia corneana após ceratectomia fotorrefrativa em paciente apresentando padrão tomográfico suspeito no pré-operatório, mas sem alterações degenerativas associadas a ceratocone patológico, conforme revelado por microscopia confocal in vivo da córnea. Além disso, revisamos, na literatura, relatos de casos elegíveis de ectasia pós-ceratectomia fotorrefrativa para encontrar características semelhantes.

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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.

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Objetivo: Determinar parámetros aberrométricos de la córnea para la detección del queratocono subclínico. Métodos: Se realizó un estudio observacional, analítico de corte transversal que incluyó 36 pacientes con queratocono subclínico (grupo de estudio) y 36 estudiantes con córneas aparentemente sanas (grupo control), que asistieron a la consulta de córnea del Instituto Cubano de Oftalmología Ramón Pando Ferrer, entre mayo de 2018 y junio de 2022. Se analizaron topografía y aberrometría corneal con el tomógrafo corneal Pentacam AXL. Resultados: El grupo queratocono subclínico mostró valores similares para la queratometría, asfericidad corneal, paquimetría y el valor total de desviación en comparación con el grupo normal. Hubo diferencias estadísticamente significativas en los parámetros aberrométricos, como el coma a 90º (Z3 -1), y la raíz cuadrada media de las aberraciones de alto orden, de cara anterior, posterior y total corneal, en queratocono subclínico en comparación con el grupo normal. El coma posterior a 90º presentó un área bajo la curva (0,894) mayor dentro de las aberrometrías, con un punto de corte de -0,013 µm, con sensibilidad del 86,1 por ciento y especificidad del 88,9 por ciento. Conclusiones: El coma posterior a 90º (parámetro aberrométrico) presenta una alta sensibilidad y especificidad para el diagnóstico de queratocono subclínico, mediante el análisis tomográfico Pentacam AXL(AU)

Objective: To determine corneal aberrometric parameters for the detection of subclinical keratoconus. Methods: An observational, analytical, cross-sectional study was performed including 36 patients with subclinical keratoconus (study group) and 36 students with apparently healthy corneas (control group), who attended the cornea consultation at the Cuban Institute of Ophthalmology Ramón Pando Ferrer, between May 2018 and June 2022. Corneal topography and aberrometry were analyzed with the Pentacam AXL corneal tomographer. Results: The subclinical keratoconus group showed similar values for keratometry, corneal asphericity, pachymetry and total deviation value compared to the normal group. There were statistically significant differences in aberrometric parameters, such as coma at 90° (Z3-1), and root mean square of high-order anterior, posterior and total corneal aberrations in subclinical keratoconus compared to the normal group. The 90° posterior coma presented a higher area under the curve (0.894) within the aberrometries, with a cutoff point of -0.013 µm, with sensitivity of 86.1 percent and specificity of 88.9 percent. Conclusions: Coma posterior to 90º (aberrometric parameter) presents high sensitivity and specificity for the diagnosis of subclinical keratoconus, using Pentacam AXL tomographic analysis(AU)

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PURPOSE: To review the prevalence and describe the characteristics, of cases with late-onset intracorneal ring segments (ICRS) keratopathy in a multicenter study. METHODS: A retrospective multicentric case-series study was performed in a specialized keratoconus service, from Buenos Aires, Argentina. An electronic clinical chart from patients with ICRS keratopathy between January 1999 and January 2019 was reviewed. We included cases with late-onset distal-apical ICRS keratopathy, which was defined as a persistent corneal lesion developed 12 months or later after implantation, located over, around, or closer to the ICRS. All the surgeries were performed by a manual corneal tunnel creation technique. Samples were taken to rule out infectious etiology. RESULTS: From 5217 eyes that underwent ICRS implantation, 13 cases (0.24%) were detected. The keratopathy onset was 72 ± 42.98 months (29-133) after ICRS implantation. Cultures were negative in all cases. An ICRS exchange was made for five cases in stage I and four in stage II. Four cases presented with partial ICRS extrusion in stage III. ICRS exchange was possible in two of them and a penetration keratoplasty was necessary for the rest. All cases remained stable 1 year after surgical procedures. CONCLUSIONS: A late-onset distal-apical ICRS keratopathy was detected with low prevalence (0.24%) in a large sample. It was classified into three stages according to its severity. Different treatments were selected for each stage, obtaining stable results 1 year after treatment.

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BACKGROUND: Recent studies have presented inflammatory features on keratoconus (KC) and many inflammatory markers are described in the tears of patients with this disease. The KC pathogenesis is still unknown just like the correlation with inflammatory patterns. However, environmental and genetic issues may be part of the progress of KC. In addition, some systemic features, such as allergy and obesity, seem to be related to the progression of KC. Our purpose was to evaluate the neuropeptides vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), chemokines ligand 2 (CCL-2) and 5 (CCL-5), and interleukins 6 (IL-6) and 8 (IL-8) on corneal epithelial cells and blood of patients with KC and in healthy controls. In addition, the neutrophil-to-lymphocyte ratio (NLR) was evaluated to predict inflammation. METHODS: This including prospective observational study included 32 KC patients who underwent corneal crosslinking (CXL) and 32 control patients who underwent photorefractive keratectomy (PRK). Patients' corneal epithelial cells were removed surgically, and blood (buffy coat) was analyzed. Samples in triplicate were evaluated on rt-PCR for neuropeptides (VIP e NPY), interleukins (IL-6 e IL-8), and chemokines (CCL-2 and CCL-5). RESULTS: Our study showed statistically higher CCL-5 and IL-8 on corneal epithelial cells in patients with KC. Blood cells were statistically higher in VIP and NPY in the KC group. Interleukin-8 on blood cells was statistically significant in KC'S group; for CCL-2 and CCL-5 they were statistically lower in patients with KC compared with controls. NLR showed no difference between the groups. CONCLUSIONS: Our data support the findings of other studies that suggested altering KC status, such as inflammatory corneal disease. The presence of IL-8 in the cornea and blood samples of KC's group suggested systemic disease with a possible local or repercussion action. Further studies are warranted to elucidate KC pathogenesis and its correlation to systemic disease.

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ABSTRACT Purpose: This study aimed to compare the clinical outcomes following deep anterior lamellar keratoplasty and penetrating keratoplasty in contralateral eyes of the same patients. Methods: In this retrospective, comparative case series, clinical outcome data included best-corrected visual acuity, refractive spherical equivalent, refractive astigmatism, endothelial cell density, endothelial cell loss, central corneal thickness, and intraocular pressure, which were evaluated at 6, 12, 24, and 36 months after deep anterior lamellar keratoplasty and penetrating keratoplasty. Additionally, complications were assessed. Results: Fifty-two eyes (26 patients) were included, of which 19 patients had keratoconus, 6 had stromal dystrophy, and 1 had post-laser-assisted in situ keratomileusis ectasia. The mean follow-up was 44.1 ± 10.5 months in the deep anterior lamellar keratoplasty Group and 47.9 ± 11.9 months in the penetrating keratoplasty Group. No significant differences were observed in the mean best-corrected visual acuity, refractive spherical equivalent, refractive astigmatism, and central corneal thickness between the deep anterior lamellar keratoplasty and penetrating keratoplasty Groups during follow-up. The endothelial cell density was significantly higher in the deep anterior lamellar keratoplasty Group than in the penetrating keratoplasty Group at 24 and 36 months postoperatively (p=0.022 and 0.013, respectively). Endothelial cell loss was significantly lower in the deep anterior lamellar keratoplasty Group than in the penetrating keratoplasty Group at 24 and 36 months postoperatively (p=0.025 and 0.001, respectively). Intraocular pressure was significantly lower in the deep anterior lamellar keratoplasty Group than in the penetrating keratoplasty Grroup at 6 months postoperatively (p=0.015). Microperforation occurred in 4 eyes (15%) during deep anterior lamellar keratoplasty surgery; however, penetrating keratoplasty was not required. No endothelial rejection occurred in the penetrating keratoplasty Group during follow-up. Conclusions: Over the 3-year follow-up, endothelial cell loss and intraocular pressure in the deep anterior lamellar keratoplasty Group were significantly lower than those in the penetrating keratoplasty Group, while visual and refractive results were similar.

RESUMO Objetivo: Este estudo teve como objetivo comparar os resultados clínicos após ceratoplastia lamelar anterior profunda e ceratoplastia penetrante nos olhos contralaterais dos mesmos pacientes. Métodos: Nesta série de casos comparativa e retrospectiva, avaliaram-se os seguintes dados de resultados clínicos: melhor acuidade visual corrigida, equivalente esférico refrativo, astigmatismo refrativo, densidade de células endoteliais, perda de células endoteliais, espessura central da córnea e pressão intraocular. Esses dados foram avaliados aos 6, 12, 24 e 36 meses após ceratoplastia lamelar anterior profunda e ceratoplastia penetrante. Também foram avaliadas as complicações. Resultados: Foram incluídos 52 olhos (26 pacientes), sendo que 19 pacientes apresentavam ceratocone, 6 apresentavam distrofia estromal e 1 apresentava ectasia após ceratomileuse in situ assistida por laser. O tempo médio de acompanhamento foi de 44,1 ± 10,5 meses no grupo da ceratoplastia lamelar anterior profunda e 47,9 ± 11,9 meses no grupo da ceratoplastia penetrante. Nenhuma diferença significativa foi observada nas médias da melhor acuidade visual corrigida, equivalente esférico refrativo, astigmatismo refrativo e espessura central da córnea entre os grupos da ceratoplastia lamelar anterior profunda e da ceratoplastia penetrante durante o acompanhamento. A densidade de células endoteliais foi significativamente maior no grupo da ceratoplastia lamelar anterior profunda que no grupo da ceratoplastia penetrante aos 24 e 36 meses de pós-operatório (p=0,022 e 0,013, respectivamente). A perda de células endoteliais foi significativamente menor no grupo da ceratoplastia lamelar anterior profunda que no grupo da ceratoplastia penetrante aos 24 e 36 meses de pós-operatório (p=0,025 e 0,001, respectivamente). A pressão intraocular foi significativamente menor no grupo da ceratoplastia lamelar anterior profunda que no grupo da ceratoplastia penetrante aos 6 meses de pós-operatório (p=0,015). Ocorreu microperfuração em 4 olhos (15%) durante a cirurgia de ceratoplastia lamelar anterior profunda; entretanto, a ceratoplastia penetrante não foi necessária. Não ocorreu nenhuma rejeição endotelial no grupo da ceratoplastia penetrante durante o período de acompanhamento. Conclusões: Durante o acompanhamento de 3 anos, a perda de células endoteliais e a pressão intraocular foram significativamente menores no grupo da ceratoplastia lamelar anterior profunda que no grupo da ceratoplastia penetrante, mas os resultados visuais e refrativos foram semelhantes.