Profundidad de la línea de demarcación del estroma corneal después de la reticulación del colágeno corneal usando epitelial corneal personalizado versus convencional desbridamiento / Corneal stromal demarcation line depth after corneal collagen cross-linking using customized versus conventional corneal epithelial debridement

Aim of the Study: Compare the corneal demarcation line (DL) depth after corneal collagen cross-linking (CXL) with subtotal versus customized corneal epithelium debridement using anterior segment optical coherence tomography (AS-OCT). Design: Prospective case-control study. Materials and Methods: The study enrolled 18 patients with bilateral progressive keratoconus. Both eyes treated by CXL using 3 mW/cm2 / 30 minutes setting. One eye with subtotal epithelial debridement (about 9 mm diameter) and the contralateral eye with customized debridement (approximately 1 mm single horizontal central scratch). One month postoperatively, patients had AS-OCT imaging to detect and measure the depth ofDL. Results: Patients' age mean was 25.17 years +/- 4.81 SD. Epithelial healing completed with in 3-7 days in conventional treatment group and demarcation line was evident in 16 eyes (89%) with a mean depth of 290.31 µm while in customized debridement group, the epithelial healing lasted less than 24 hours and DL was detectable in 10 patients (55.5 %) with a mean DL depth of 221 µm with a statistically significant difference (p < 0.05). Subjective postoperative pain graded as "moderate to severe" in about 77% of eyes underwent 9 mm epi-off CXL compared with 55% of those with customized debridement group. Conclusions: Although the DL if found in majority cases, but the shallow location in customized corneal debridement cases questioned the efficacy of this technique despite the quick re-epithelialization and less postoperative pain that accompanied it

Corneal differences between healthy and subclinical patients assessed using two diferente corneal tomographers / Diferenças entre as córneas de pacientes saudáveis e pacientes subclínicos avaliados com dois tipos de tomógrafos de córnea

ABSTRACT Purpose: To analyze subclinical keratoconus topography indexes using Pentacam and Orbscan-II measurements to identify evidences for seeking sensitive indexes to screen and diagnose subclinical keratoconus. Methods: Fifty healthy participants (50 eyes) and 40 patients with subclinical keratoconus (40 eyes) were included. Seven common parameters including corneal thickness at the thinnest point; minimum curvature of the front surface (minimum simulated keratometry value, SimK's Min); maximum curvature of the front surface (maximum simulated keratometry value, SimK's Max); the frontal corneal surface best-fit spherical radius of the curvature; the back corneal surface best-fit spherical radius of curvature; the anterior corneal surface height (anterior Diff value); and the posterior corneal surface height (posterior Diff value) measured by Pentacam and Orbscan-II between normal and subclinical keratoconus eyes were compared. Results: Statistical differences between the healthy and subclinical keratoconus groups (p<0.01) were found in all corneal parameters measured using both devices. Differences in the minimum curvature of the front surface (SimK's Min), thinnest point, anterior Diff value, and posterior Diff value were significant between Pentacam and Orbscan-II in the subclinical keratoconus group (p<0.05). Conclusion: The findings of this study identify the differences between normal and subclinical keratoconus eyes at the minimum curvature of the front surface, maximum curvature of the front surface, frontal corneal surface best-fit spherical radius of curvature, back corneal surface best-fit spherical radius of curvature, Anterior Diff value, and Posterior Diff value measures using Orbscan II and Pentacam that can help eye care practitioners clinically diagnose subclinical keratoconus.

RESUMO Objetivo: Analisar os índices subclínicos de to pografia de ceratocone utilizando as medidas feitas com Pentacam e com Orbscan-II para identificar evidências para a busca de índices sensíveis para triagem e diagnóstico de ceratocone subclínico. Métodos: Cinquenta participantes saudáveis (50 olhos) e 40 pacientes com ceratocone subclínico (40 olhos) foram incluídos. Sete parâmetros comuns, incluindo a espessura da córnea no ponto mais fino; a curvatura mínima da superfície frontal (valor mínimo da ceratometria simulada, Min de SimK); a curvatura máxima da superfície frontal (valor máximo da ceratometria simulada, Max de SimK); a superfície frontal e a superfície posterior da córnea de melhor ajuste ao raio da curvatura, a altura da superfície anterior da córnea (valor Diff anterior) e a altura da superfície corneana posterior (valor Diff posterior) medidos pelo Pentacam e pelo Orbscan-II entre os olhos normais e com ceratocone subclínico foram comparados. Resultados: As diferenças estatísticas entre os grupos saudável e com ceratocone subclínico (p<0,01) foram encontradas em todos os parâmetros corneanos medidos usando ambos os dispositivos. Diferenças na curvatura mínima da superfície frontal (Min de SimK) no ponto mais fino, no valor Diff anterior e no valor Diff posterior foram significativas entre Pentacam e Orbscan-II no grupo com ceratocone subclínico (p<0,05). Conclusão: Os achados deste estudo identificam as diferenças entre olhos normais e com ceratocone subclínico para a curvatura mínima da superfície frontal, a curvatura máxima da superfície frontal, a superfície corneana frontal e a superfície corneana posterior de melhor ajuste ao raio esférico da curvatura e as medidas de Diff anterior e posterior usando Orbscan II e o Pentacam que podem auxiliar os profissionais de oftalmologia a diagnosticar clinicamente o ceratocone subclínico.

Corneal differences between healthy and subclinical patients assessed using two diferente corneal tomographers.

PURPOSE: To analyze subclinical keratoconus topography indexes using Pentacam and Orbscan-II measurements to identify evidences for seeking sensitive indexes to screen and diagnose subclinical keratoconus. METHODS: Fifty healthy participants (50 eyes) and 40 patients with subclinical keratoconus (40 eyes) were included. Seven common parameters including corneal thickness at the thinnest point; minimum curvature of the front surface (minimum simulated keratometry value, SimK's Min); maximum curvature of the front surface (maximum simulated keratometry value, SimK's Max); the frontal corneal surface best-fit spherical radius of the curvature; the back corneal surface best-fit spherical radius of curvature; the anterior corneal surface height (anterior Diff value); and the posterior corneal surface height (posterior Diff value) measured by Pentacam and Orbscan-II between normal and subclinical keratoconus eyes were compared. RESULTS: Statistical differences between the healthy and subclinical keratoconus groups (p<0.01) were found in all corneal parameters measured using both devices. Differences in the minimum curvature of the front surface (SimK's Min), thinnest point, anterior Diff value, and posterior Diff value were significant between Pentacam and Orbscan-II in the subclinical keratoconus group (p<0.05). CONCLUSION: The findings of this study identify the differences between normal and subclinical keratoconus eyes at the minimum curvature of the front surface, maximum curvature of the front surface, frontal corneal surface best-fit spherical radius of curvature, back corneal surface best-fit spherical radius of curvature, Anterior Diff value, and Posterior Diff value measures using Orbscan II and Pentacam that can help eye care practitioners clinically diagnose subclinical keratoconus.

Effect of accelerated corneal crosslinking on ocular response analyzer waveform-derived parameters in progressive keratoconus / Efeito do crosslimking corneano acelerado nos parâmetros derivados da forma de onda do analisador de resposta ocular no ceratocone progressivo

ABSTRACT Purpose: To evaluate the effect of accelerated corneal crosslinking on corneal biomechanics with an ocular response analyzer in patients with progressive keratoconus. Methods: In this retrospective study, 50 eyes of 45 patients with progressive keratoconus who underwent accelerated corneal crosslinking were evaluated with ocular response analyzer waveform parameters before and one year after corneal crosslinking. Paired two-tailed Student's t-test was performed to compare the parameters before vs. after corneal crosslinking. Results: Mean patient age was 17.6 ± 3.6 (range 9-25) years. A significant increase was observed in p1 area, p2 area, h2, and dive2 values. No significant difference in corneal hysteresis, corneal resistance factor, or other waveform-derived parameters was observed at one year postoperatively. Conclusion: For estimating the effect of accelerated corneal crosslinking on corneal biomechanics, parameters such as p1 area, p2 area, h2, and dive2 are more sensitive than corneal hysteresis and corneal resistance factor. These results may help us to find out which corneal crosslinking method is most effective for stiffening the cornea.

RESUMO Objetivo: Avaliar o efeito do cross-linking corneano acelerado na biomecânica corneana com analisador de resposta ocular em pacientes com ceratocone progressivo. Métodos: Neste estudo retrospectivo, 50 olhos de 45 pacientes com ceratocone progressivo submetidos à cross-linking corneano acelerado foram avaliados com os parâmetros da forma de onda do analisador de resposta ocular antes e um ano após o tratamento com cross-linking corneano. O teste t de Student pareado bicaudal foi realizado para comparar os parâmetros antes e depois do cross-linking corneano. Resultados: A média de idade dos pacientes foi de 17,6 ± 3,6 (variação de 9 a 25) anos. Um aumento significativo foi observado nos valores de p1area, p2area, h2 e dive2. Nenhuma diferença significativa foi encontrada na histerese da córnea, fator de resistência da córnea ou outros parâmetros derivados da forma de onda foi observada em um ano de pós-operatório. Conclusão: Para estimar o efeito do cross-linking corneano acelerado na biomecânica corneana, parâmentros como p1area, p2area, h2 e dive2 são mais sensíveis que histerese da córnea e fator de resistência corneana. Esses resultados podem nos ajudar a descobrir qual método cross-linking corneano é mais eficaz no enrijecimento da córnea.

Posterior keratoconus and iris atrophy: a fortuitous association? / Ceratocone posterior e atrofia de iris: uma associação incidental?

ABSTRACT The authors describe an unusual association between posterior keratoconus and iris atrophy, confirmed by a complete ocular evaluation, scheimpflug imaging and pachymetric curve. A hypothesis for concomitant findings is discussed.

RESUMO Os autores descrevem a rara associação entre ceratocone posterior e atrofia de íris, confirmada por avaliação oftalmológica completa, imagens de scheimpflug e curva paquimétrica. Sugere-se uma hipótese que explique a concomitância de ambas as alterações.

Posterior keratoconus and iris atrophy: a fortuitous association?

The authors describe an unusual association between posterior keratoconus and iris atrophy, confirmed by a complete ocular evaluation, scheimpflug imaging and pachymetric curve. A hypothesis for concomitant findings is discussed.

Effect of accelerated corneal crosslinking on ocular response analyzer waveform-derived parameters in progressive keratoconus.

PURPOSE: To evaluate the effect of accelerated corneal crosslinking on corneal biomechanics with an ocular response analyzer in patients with progressive keratoconus. METHODS: In this retrospective study, 50 eyes of 45 patients with progressive keratoconus who underwent accelerated corneal crosslinking were evaluated with ocular response analyzer waveform parameters before and one year after corneal crosslinking. Paired two-tailed Student's t-test was performed to compare the parameters before vs. after corneal crosslinking. RESULTS: Mean patient age was 17.6 ± 3.6 (range 9-25) years. A significant increase was observed in p1 area, p2 area, h2, and dive2 values. No significant difference in corneal hysteresis, corneal resistance factor, or other waveform-derived parameters was observed at one year postoperatively. CONCLUSION: For estimating the effect of accelerated corneal crosslinking on corneal biomechanics, parameters such as p1 area, p2 area, h2, and dive2 are more sensitive than corneal hysteresis and corneal resistance factor. These results may help us to find out which corneal crosslinking method is most effective for stiffening the cornea.

[Experiencia con crosslinking en pacientes mexicanos con queratocono y variables queratométricas como factores pronóstico de agudeza visual]. / Experience with crosslinking in Mexican patients with keratoconus and keratometric values as prognostic factors of visual acuity.

OBJETIVO: El objetivo del estudio fue describir los resultados visuales y queratométricos de pacientes con queratocono sometidos a tratamiento con crosslinking (CXL). MÉTODO: Estudio retrospectivo de 277 ojos de 144 pacientes con queratocono progresivo que se sometieron a CXL. Se obtuvieron mediciones topográficas antes del procedimiento y 12 meses después. La agudeza visual corregida (AVC), la queratometría más plana (K1), la queratometría más curva (K2), el promedio de la queratometría (Kprom), el cilindro, el eje de K1, el eje de K2 y el valor paquimétrico del punto de la córnea más delgado fueron las variables evaluadas. RESULTADOS: A los 12 meses de seguimiento, los valores de AVC mejoraron. Hubo disminuciones estadísticamente significativas en K1 (p = 0,001), K2 (p = 0.000), eje de K1 (p = 0.000), eje de K2 (p = 0.004) y Kprom (p = 0.025). El análisis de correlación mostró que la AVC, la K1, la K2, el eje de K2, el Kprom y el cilindro preoperatorios, así como la K1, la K2, el Kprom y el cilindro posoperatorios, afectan significativamente la agudeza visual a los 12 meses de seguimiento. CONCLUSIONES: El CXL es un tratamiento eficaz para mejorar la AVC a 1 año de seguimiento en el grupo de pacientes estudiados. Los valores de K preoperatorios y posoperatorios, y la AVC preoperatoria, se correlacionan de forma significativa con la AVC a los 12 meses de la aplicación del CXL. OBJECTIVE: The present study aimed to report the outcomes of patients with progressive keratoconus who were treated via conventional crosslinking (CXL). METHOD: This retrospective study included 277 eyes of 144 patients with progressive keratoconus who underwent CXL. Topographical measurements were obtained preoperatively and twelve months postoperatively. The best corrected visual acuity (BCVA), flat keratometry (K) value (K1), steep K value (K2), average K value (avgK), K1 axis, K2 axis, pachymetry value and cylindrical value were the studied measures. RESULTS: At the 12-month follow-up, the mean BCVA values were improved. Statistically significant decreases in K1 (p = 0,001), K2 (p = 0.000), K1 axis (p = 0.000), K2 axis (p = 0.004) and avgK (p = 0.025) were observed. The correlation analysis revealed that the preoperative BCVA, K1, K2, K2 axis, avgK and cylinder as well as postoperative K1, K2, avgK and cylinder values significantly affected visual acuity at the 12-month follow-up. CONCLUSIONS: CXL was an effective treatment to improve best corrected visual acuity. The preoperative and postoperative K values, preoperative BCVA had a statistically significant correlation with BCVA at 12 months after CXL treatment.

Long-term efficacy and safety after corneal collagen crosslinking in pediatric patients: Three-year follow-up.

PURPOSE: To evaluate the effectiveness of standard corneal collagen crosslinking for children with progressive keratoconus. METHODS: Prospective study including 26 eyes of 26 patients younger than 18 years old with progressive keratoconus at Oftalmosalud Instituto de Ojos, Lima, Peru. Standard epi-off corneal crosslinking was performed in all eyes between January 2012 and January 2013. Pre- and postoperative evaluation (at 3 years) included uncorrected and best-corrected visual acuity and Scheimpflug analysis. Crosslinking failure was defined as an increase in maximum keratometry (Kmax) of more than 1 diopter after 1 year or more. RESULTS: Mean uncorrected visual acuity improvement was 0.24 LogMAR (p = 0.07) and mean best-corrected visual acuity improvement was 0.18 LogMAR (p = 0.01). None of the eyes lost more than one line in the best-corrected visual acuity. Four eyes (15.38%) lost two lines in the uncorrected visual acuity at 3 years postoperative. Mean steeper keratometry improvement was 1.14 diopters (p = 0.60). Progression rate was 23.07%. CONCLUSION: Standard epi-off corneal collagen crosslinking is safe and effective to halt the progression of the keratoconus with significant improvement in the best-corrected visual acuity at 3-year follow-up.

Evaluation of anterior segment parameters using Scheimpflug technology during the Valsalva maneuver in patients with keratoconus / Avaliação de parâmetros do segmento anterior usando a tecnologia Scheimpflug durante a manobra de Valsalva em pacientes com ceratocone

ABSTRACT Purpose: This study aimed to explore the effects of the Valsalva maneuver (VM) on ectatic corneas during anterior segment tomography scans using a Scheimpflug camera. Methods: This prospective observational study included 100 eyes of 50 patients with bilateral keratoconus (KC). Anterior segment tomography was first performed when the patients were in a resting position and immediately repeated as the participant performed VM. Scheimpflug images were taken using a Pentacam®. Results: The mean age of the participants was 24.14 ± 6.59 years. Of the 100 eyes included in the study, 7% had stage 1 KC, 47% had stage 2 KC, 32% had stage 3 KC, and 14% had stage 4 KC. The indices of KC were not significantly affected by VM. Similarly, no statistically significant differences were found between the stages of KC, or with the mean pachymetric progression index during VM. Pupil diameter showed a statistically significant increase during VM (p=0.017). There was a statistically significant decrease in the anterior chamber angle measurement during VM (p=0.001). Maximum curvature power in the front of the cornea decreased more during VM in stage 4 KC than for the other stages (p=0.014). Conclusions: No changes associated with VM were found in the KC indices or the stage of the disease. However, an increase in pupil diameter and a decrease in anterior chamber angle value were found. These changes were comparable to values obtained from previous studies performed on normal corneas.

RESUMO Objetivo: Este estudo tem como objetivo explorar os efeitos da manobra de Valsalva (VM) na córnea ectásica durante a varredura tomográfica do segmento anterior usando a câmera de Scheimpflug. Métodos: Foi conduzido estudo observacional, prospectivo envolvendo 100 olhos de 50 pacientes que apresentavam ceratocone (KC) bilateral. Tomografia do segmento anterior foi realizada inicialmente quando os pacientes estavam em posição de repouso e imediatamente depois, no curso de VM. Imagens de Scheimpflug foram feitas usando Pentacam®. Resultados: A média de idade dos participantes foi 24,14 ± 6,59 anos de idade. Dos olhos incluídos no estudo, 7% apresentava KC estágio 1,47% apresentava estágio 2,32% apresentava estágio 3, e 14% apresentava estágio 4. Índices de KC não foram significativamente afetadas pela VM. Não houve diferenças estatisticamente significativas com o estágio do KC, e o índice médio de progressão paquimétrica durante a VM. O diâmetro da pupila (PD) mostrou aumento estatisticamente significativo durante a VM (p=0,017). Houve diminuição estatisticamente significativa na medida do ângulo da câmara anterior durante a VM (p=0,001). O poder máximo de curvatura anterior da córnea no KC estágio 4 diminuiu mais do que os outros estágios durante o VM (p=0,014). Conclusões: Não foram encontradas alterações nos índices KC e no estágio da doença por causa da VM. Verificou-se que houve aumento na PD e uma diminuição no valor do ângulo da câmara anterior. Estas alterações foram comparáveis aos valores obtidos a partir de estudos realizados em córneas normais.

Differentiation of mild keratoconus from corneal warpage according to topographic inferior steepening based on corneal tomography data.

We report two cases of suspicious asymmetric bow tie and inferior steepening on topographic evaluations with reflection (Placido) and projection (Scheimpflug). Rotating Scheimpflug corneal and anterior segment tomography (Oculus Pentacam HR, Wetzlar, Germany)® was performed in the first case, with a maximal keratometric value (Kmax) of 43.2 D and an overall deviation value from the Belin/Ambrósio Enhanced Ectasia Display (BAD-D) of 1.76, which was observed in the study eye (OD). BAD-D was 6.59 in the fellow eye, which had clinical findings that were consistent with keratoconus stage 2. The second case presented with a Kmax of 45.3 D and BAD-D of 0.76 in OD and 1.01 in OS. This patient had discontinued wearing soft contact lens less than 1 day prior to examination. Corneal tomographic data enabled us to distinguish mild or forme fruste keratoconus from contact lens-induced corneal warpage, and similar findings were observed on curvature maps.

Differentiation of mild keratoconus from corneal warpage according to topographic inferior steepening based on corneal tomography data / Diferenciação de ceratocone leve e deformação corneana por lente de contato com encurvamento inferior baseado em dados da tomografia de córnea

ABSTRACT We report two cases of suspicious asymmetric bow tie and inferior steepening on topographic evaluations with reflection (Placido) and projection (Scheimpflug). Rotating Scheimpflug corneal and anterior segment tomography (Oculus Pentacam HR, Wetzlar, Germany)® was performed in the first case, with a maximal keratometric value (Kmax) of 43.2 D and an overall deviation value from the Belin/Ambrósio Enhanced Ectasia Display (BAD-D) of 1.76, which was observed in the study eye (OD). BAD-D was 6.59 in the fellow eye, which had clinical findings that were consistent with keratoconus stage 2. The second case presented with a Kmax of 45.3 D and BAD-D of 0.76 in OD and 1.01 in OS. This patient had discontinued wearing soft contact lens less than 1 day prior to examination. Corneal tomographic data enabled us to distinguish mild or forme fruste keratoconus from contact lens-induced corneal warpage, and similar findings were observed on curvature maps.

RESUMO O presente estudo tem por objetivo relatar dois casos suspeitos que apresentam bow tie assimétrico e encurvamento inferior nas avaliações topográficas de reflexão (Placido) e projeção (Scheimpflug). A tomografia de córnea e segmento anterior com o sistema Scheimpflug (Oculus Pentacam HR, Wetzlar, Alemanha)® mostrou no primeiro caso, a ceratometria máxima (Kmax) de 43,2 D e o valor D no Belin/Ambrósio Enhanced Ectasia Display (BAD-D) de 1,76 no olho estudado (OD). O olho contralateral apresentava BAD-D de 6,59 e achados clínicos compatíveis com ceratocone (KC) grau 2. O segundo caso apresentava Kmax de 45,3 D e BAD-D de 0,76 em OD e 1,01 em OS. Este paciente havia interrompido o uso de lentes de contato gelatinosas 1 dia antes do exame. A avaliação tomográfica avançada nos permitiu distinguir ceratocone leve ou subclínico de warpage induzido por lentes de contato, enquanto resultados semelhantes foram observados em mapas de curvatura anterior.

Six-month outcomes of corneal crosslinking with dextran-free isotonic riboflavin solution.

PURPOSE: To analyze the short-term clinical and topographic outcomes in patients with keratoconus after corneal collagen cross-linking treatment (CXL) with dextran-free isotonic riboflavin solution. METHODS: In this retrospective case series, 26 eyes from 26 patients with keratoconus were studied. The best corrected visual acuity (BCVA) and refractive and topographic findings were analyzed at a 6-month follow-up. RESULTS: The mean BCVA (Snellen lines) values before and 1, 3, and 6 months after CXL were 0.51 ± 0.2, 0.48 ± 0.2, 0.57 ± 0.2, and 0.64 ± 0.2, respectively, and the difference between the preoperative and 6-month values was statistically significant (p=0.006). The mean spherical equivalent refraction decreased from -5.6 ± 2.4 diopters (D) preoperatively to -5.0 ± 2.1 D, and mean simulated keratometry decreased from 48.5 ± 2.5 D to 47.8 ± 2.6 D at 6 months. (p=0.145 and p=0.001, respectively). In addition, the maximum keratometry decreased progressively and significantly from the preoperative value during follow-up (p=0.003). The central and minimal corneal thicknesses, including those of the epithelium, also decreased from 442.8 ± 25.6 µm and 430.5 ± 23.9 µm preoperatively to 420.7 ± 31.8 µm and 409.3 ± 28.7 µm at the most recent follow-up (p<0.001), respectively. No intraoperative or postoperative complications were observed. CONCLUSIONS: CXL with dextran-free isotonic riboflavin solution appears to be a safe treatment alternative for keratoconus and yields sustained short-term improvements in visual acuity, keratometric readings, and corneal thickness. However, long-term results are needed to confirm these outcomes.

Six-month outcomes of corneal crosslinking with dextran-free isotonic riboflavin solution / Resultados após seis meses de crosslinking de córnea com solução isotônica de riboflavina sem dextrano

ABSTRACT Purpose: To analyze the short-term clinical and topographic outcomes in patients with keratoconus after corneal collagen cross-linking treatment (CXL) with dextran-free isotonic riboflavin solution. Methods: In this retrospective case series, 26 eyes from 26 patients with keratoconus were studied. The best corrected visual acuity (BCVA) and refractive and topographic findings were analyzed at a 6-month follow-up. Results: The mean BCVA (Snellen lines) values before and 1, 3, and 6 months after CXL were 0.51 ± 0.2, 0.48 ± 0.2, 0.57 ± 0.2, and 0.64 ± 0.2, respectively, and the difference between the preoperative and 6-month values was statistically significant (p=0.006). The mean spherical equivalent refraction decreased from -5.6 ± 2.4 diopters (D) preoperatively to -5.0 ± 2.1 D, and mean simulated keratometry decreased from 48.5 ± 2.5 D to 47.8 ± 2.6 D at 6 months. (p=0.145 and p=0.001, respectively). In addition, the maximum keratometry decreased progressively and significantly from the preoperative value during follow-up (p=0.003). The central and minimal corneal thicknesses, including those of the epithelium, also decreased from 442.8 ± 25.6 µm and 430.5 ± 23.9 µm preoperatively to 420.7 ± 31.8 µm and 409.3 ± 28.7 µm at the most recent follow-up (p<0.001), respectively. No intraoperative or postoperative complications were observed. Conclusions: CXL with dextran-free isotonic riboflavin solution appears to be a safe treatment alternative for keratoconus and yields sustained short-term improvements in visual acuity, keratometric readings, and corneal thickness. However, long-term results are needed to confirm these outcomes.

RESUMO Objetivo: Analisar os resultados clínicos e topográficos curto prazo após crosslinking (CXL) de córnea com solução isotônica de riboflavina sem dextrano, em pacientes com ceratocone. Método: Estudamos 26 olhos de 26 pacientes com ceratocone, nesta série retrospectiva de casos. Melhor acuidade visual corrigida (BCVA), refração e achados topográficos foram analisados aos 6 meses de acompanhamento. Resultados: BCVA pré-operatória (linhas de Snellen) foi de 0,51 ± 0,2. BCVA após CXL foram de 0,48 ± 0,2, 0,57 ± 0,2 e 0,64 ± 0,2 no 1º, 3º e 6º meses, respectivamente. A diferença entre a BCVA pré-operatória e mais recente foi estatisticamente significativa (p=0,006). O equivalente esférico médio diminuiu de -5,6 ± 2,4 dioptrias (D) no pré-operatório para -5.0 ± 2.1 D e a média da ceratometria simulada diminuiu de 48,5 ± 2,5 D para 47, 8± 2,6 D aos 6 meses. (p=0,145 e p=0,001, respectivamente). A ceratometria máxima diminuiu progressivamente durante o acompanhamento com as mudanças sendo significativamente diferentes do valor pré-operatório (p=0,003). As espessuras corneanas central e mínima, diminuiram de 442,8 ± 25,6 µm e 430,5 ± 23,9 µm para 420,7 ± 31,8 µm e 409,3 ± 28,7 µm, respectivamente, na visita mais recente (p<0,001). Não foram observadas complicações intraoperatórias e pós-operatórias. Conclusões: CXL com solução de riboflavina isotônica sem dextrano parece ser uma opção segura de tratamento para o ceratocone com melhora mantida na acuidade visual, ceratometria e espessura corneana, no curto prazo. Resultados a longo prazo são necessários para confirmar estes resultados.

Descriptive analysis of the type and design of contact lenses fitted according to keratoconus severity and morphology.

PURPOSE: Keratoconus is characterized by bilateral asymmetrical corneal ectasia that leads to inferior stromal thinning and corneal protrusion. There is currently a lack of consensus regarding the most efficacious method for fitting contact lenses in patients with keratoconus, given the various topographical patterns and evolution grades observed in affected populations. The purpose of the present study was to evaluate the association between keratoconus evolution grade and topography pattern and the type and design of fitted contact lens. METHODS: We performed a retrospective analysis of contact lenses fitted in a total of 185 patients with keratoconus (325 eyes). Keratoconus was classified as either grade I, II, III, or IV based on keratometry and cone morphology (nipple, oval, globus, or indeterminate) results. RESULTS: A total of 325 eyes were evaluated in the present study. Of the 62 eyes classified as grade I, 66.1% were fitted with monocurve contact lenses. Of the 162 eyes classified as grade I and II, 51%, 30%, and 19% were fitted with adapted monocurve rigid gas-permeable contact lenses (RGPCL), bicurve lenses, and others lens types, respectively. Bicurve lenses were fitted in 52.1% and 62.2% of eyes classified as grade III and IV, respectively. Of the eyes classified as grade III and IV, monocurve and bicurve RGPCL were fitted in 26% and 55%, respectively. In eyes with oval keratoconus, 45%, 35%, and 20% were fitted with monocurve lenses, bicurve lenses, and other lens types, respectively. In eyes with round cones (nipple morphology), 55%, 30%, and 15% were fitted with bicurve lenses, monocurve lenses, and other lens types, respectively. CONCLUSION: Monocurve RGPCL were most frequently fitted in patients with mild to moderate keratoconus and oval cones morphology, while bicurve lenses were more frequently fitted in patients with severe and advanced keratoconus. This was probably because bicurve lenses are more appropriate for round cones due to increased corneal asphericity.

Descriptive analysis of the type and design of contact lenses fitted according to keratoconus severity and morphology / Análise descritiva dos tipos e parâmetros das lentes de contato adaptadas de acordo com o grau evolutivo e a morfologia do ceratocone

ABSTRACT Purpose: Keratoconus is characterized by bilateral asymmetrical corneal ectasia that leads to inferior stromal thinning and corneal protrusion. There is currently a lack of consensus regarding the most efficacious method for fitting contact lenses in patients with keratoconus, given the various topographical patterns and evolution grades observed in affected populations. The purpose of the present study was to evaluate the association between keratoconus evolution grade and topography pattern and the type and design of fitted contact lens. Methods: We performed a retrospective analysis of contact lenses fitted in a total of 185 patients with keratoconus (325 eyes). Keratoconus was classified as either grade I, II, III, or IV based on keratometry and cone morphology (nipple, oval, globus, or indeterminate) results. Results: A total of 325 eyes were evaluated in the present study. Of the 62 eyes classified as grade I, 66.1% were fitted with monocurve contact lenses. Of the 162 eyes classified as grade I and II, 51%, 30%, and 19% were fitted with adapted monocurve rigid gas-permeable contact lenses (RGPCL), bicurve lenses, and others lens types, respectively. Bicurve lenses were fitted in 52.1% and 62.2% of eyes classified as grade III and IV, respectively. Of the eyes classified as grade III and IV, monocurve and bicurve RGPCL were fitted in 26% and 55%, respectively. In eyes with oval keratoconus, 45%, 35%, and 20% were fitted with monocurve lenses, bicurve lenses, and other lens types, respectively. In eyes with round cones (nipple morphology), 55%, 30%, and 15% were fitted with bicurve lenses, monocurve lenses, and other lens types, respectively. Conclusion: Monocurve RGPCL were most frequently fitted in patients with mild to moderate keratoconus and oval cones morphology, while bicurve lenses were more frequently fitted in patients with severe and advanced keratoconus. This was probably because bicurve lenses are more appropriate for round cones due to increased corneal asphericity.

RESUMO Objetivo: O ceratocone é uma ectasia corneana bilateral e assimétrica que leva a afinamento corneano inferior e protrusão da córnea, não existe consenso sobre qual é o melhor caminho para adaptar lentes de contato em pacientes com ceratocone, considerando seus diferentes padrões topográficos e graus de evolução. O objetivo desse estudo é associar o grau de evolução e padrão topográfico com o tipo/desenho da lente adaptada. Métodos: Análise retrospectiva das lentes de contato adaptadas em 185 pacientes com ceratocone (325 olhos) no Departamento de Lentes de Contato. O ceratocone foi classificado de acordo com a ceratometria em graus I, II, III e IV e de acordo com a morfologia em cone redondo, oval, globoso e indeterminado. Resultados: Foram avaliados 325 olhos. Em 66,1% dos olhos com grau I foi adaptada lente monocurva. Dos 162 olhos classificados como graus I e II foram adaptadas lentes monocurva em 51%, bicurva em 30% e outros em 19%. Em relação aos olhos grau III, em 52,1% foram adaptadas lentes bicurvas e o mesmo aconteceu em 62,2% dos olhos com grau IV. Apenas 26% dos olhos grau III ou IV receberam lentes monocurva, com necessidade de bicurvas em 55%. 45% dos cones ovais foram adaptados com lentes monocurva, 35% com bicurvas e 20% com outros tipos, enquanto 55% dos cones redondos foram adaptados com lentes bicurvas, apenas 30% com monocurvas e 15% com outros desenhos. Conclusão: Lentes de contato rígida gás-permeável (LCRGP) monocurvas são mais frequentemente utilizadas em ceratocones leves e moderados e em ovais, enquanto bicurvas são mais usadas para casos graves e avançados e em cones redondos.

Evaluation of anterior segment parameters using Scheimpflug technology during the Valsalva maneuver in patients with keratoconus.

PURPOSE:: This study aimed to explore the effects of the Valsalva maneuver (VM) on ectatic corneas during anterior segment tomography scans using a Scheimpflug camera. METHODS:: This prospective observational study included 100 eyes of 50 patients with bilateral keratoconus (KC). Anterior segment tomography was first performed when the patients were in a resting position and immediately repeated as the participant performed VM. Scheimpflug images were taken using a Pentacam®. RESULTS:: The mean age of the participants was 24.14 ± 6.59 years. Of the 100 eyes included in the study, 7% had stage 1 KC, 47% had stage 2 KC, 32% had stage 3 KC, and 14% had stage 4 KC. The indices of KC were not significantly affected by VM. Similarly, no statistically significant differences were found between the stages of KC, or with the mean pachymetric progression index during VM. Pupil diameter showed a statistically significant increase during VM (p=0.017). There was a statistically significant decrease in the anterior chamber angle measurement during VM (p=0.001). Maximum curvature power in the front of the cornea decreased more during VM in stage 4 KC than for the other stages (p=0.014). CONCLUSIONS:: No changes associated with VM were found in the KC indices or the stage of the disease. However, an increase in pupil diameter and a decrease in anterior chamber angle value were found. These changes were comparable to values obtained from previous studies performed on normal corneas.

Variant c.2262A>C in DOCK9 Leads to Exon Skipping in Keratoconus Family.

PURPOSE: Keratoconus (KTCN) is a degenerative disorder of the eye that is characterized by a conical shape and thinning of the cornea, resulting in impaired visual function. Previously, we identified heterozygous single base-pair substitutions in DOCK9, IPO5, and STK24, showing concurrent 100% segregation with the affected phenotype in an Ecuadorian family. As the pathogenic consequences of these variants were not obvious, we performed in vitro splicing analyses to determine their functional significance. METHODS: We generated expression constructs using patient DNA as a template corresponding to the wild-type and mutant alleles of DOCK9, IPO5, and STK24. After transfecting HeLa cells with each construct, total RNA samples were extracted, reverse transcribed, and amplified using specific primers. RESULTS: In vitro splicing analysis revealed that only c.2262A>C in exon 20 of DOCK9 led to aberrant splicing, resulting in the changed ratio between two protein isoforms: a normal transcript and a transcript with exon skipping. The exon skipping causes a premature stop codon, disrupting the functional domains of DOCK9 protein, which may alter the biological role of DOCK9 as a Cdc42 activator. CONCLUSIONS: Based on in vitro results, we demonstrated that c.2262A>C substitution in DOCK9, previously identified in KTCN-affected members of an Ecuadorian family, leads to a splicing aberration. However, because the mutation effect was observed in vitro, a definitive relationship between DOCK9 and KTCN phenotype could not be established. Our results indicate that further elucidation of the causes of KTCN is needed.

Quantitative analysis of iris parameters in keratoconus patients using optical coherence tomography.

PURPOSE: To investigate the relationship between quantitative iris parameters and the presence of keratoconus. METHODS: Cross-sectional observational study that included 15 affected eyes of 15 patients with keratoconus and 26 eyes of 26 normal age- and sex-matched controls. Iris parameters (area, thickness, and pupil diameter) of affected and unaffected eyes were measured under standardized light and dark conditions using anterior segment optical coherence tomography (AS-OCT). To identify optimal iris thickness cutoff points to maximize the sensitivity and specificity when discriminating keratoconus eyes from normal eyes, the analysis included the use of receiver operating characteristic (ROC) curves. RESULTS: Iris thickness and area were lower in keratoconus eyes than in normal eyes. The mean thickness at the pupillary margin under both light and dark conditions was found to be the best parameter for discriminating normal patients from keratoconus patients. Diagnostic performance was assessed by the area under the ROC curve (AROC), which had a value of 0.8256 with 80.0% sensitivity and 84.6% specificity, using a cutoff of 0.4125 mm. The sensitivity increased to 86.7% when a cutoff of 0.4700 mm was used. CONCLUSIONS: In our sample, iris thickness was lower in keratoconus eyes than in normal eyes. These results suggest that tomographic parameters may provide novel adjunct approaches for keratoconus screening.

Quantitative analysis of iris parameters in keratoconus patients using optical coherence tomography / Uso de tomografia de coerência óptica na análise quantitativa dos parâmetros irianos em pacientes com ceratocone

ABSTRACTPurpose:To investigate the relationship between quantitative iris parameters and the presence of keratoconus.Methods:Cross-sectional observational study that included 15 affected eyes of 15 patients with keratoconus and 26 eyes of 26 normal age- and sex-matched controls. Iris parameters (area, thickness, and pupil diameter) of affected and unaffected eyes were measured under standardized light and dark conditions using anterior segment optical coherence tomography (AS-OCT). To identify optimal iris thickness cutoff points to maximize the sensitivity and specificity when discriminating keratoconus eyes from normal eyes, the analysis included the use of receiver operating characteristic (ROC) curves.Results:Iris thickness and area were lower in keratoconus eyes than in normal eyes. The mean thickness at the pupillary margin under both light and dark conditions was found to be the best parameter for discriminating normal patients from keratoconus patients. Diagnostic performance was assessed by the area under the ROC curve (AROC), which had a value of 0.8256 with 80.0% sensitivity and 84.6% specificity, using a cutoff of 0.4125 mm. The sensitivity increased to 86.7% when a cutoff of 0.4700 mm was used.Conclusions:In our sample, iris thickness was lower in keratoconus eyes than in normal eyes. These results suggest that tomographic parameters may provide novel adjunct approaches for keratoconus screening.

RESUMOObjetivo:Investigar a relação entre os parâmetros quantitativos irianos e a presença de ceratocone.Métodos:Estudo observacional transversal com quinze olhos de 15 pacientes com ceratocone e 26 olhos de 26 indivíduos normais, pareados por idade e gênero. Parâmetros da íris (área, espessura e diâmetro da pupila) de olhos com ceratocone e olhos sem ceratocone foram medidos usando tomografia de coerência óptica do segmento anterior (AS-OCT), em condições padronizadas de alta luminosidade e ambiente escuro. Com o objetivo de maximizar a sensibilidade, especificidade e identificar o melhor ponto de corte na diferenciação entre ceratocone e indivíduos normais, foi realizada a análise quantitativa da curva característica operacional do receptor (ROC) dos parâmetros de espessura da íris.Resultados:A área e espessura da íris estavam reduzidas nos olhos de pacientes com ceratocone. Observamos que o melhor parâmetro para discriminar indivíduos normais de pacientes com ceratocone foi a espessura média na margem pupilar, tanto em condições de alta luminosidade quanto em ambiente escuro. O desempenho diagnóstico deste parâmetro foi avaliado pela análise quantitativa da área sob a curva ROC (AROC), mostrando AROC de 0,8256, com sensibilidade de 80,0% e especificidade de 84,6% usando um ponto de corte de 0,4125 milímetros de espessura da íris. A sensibilidade aumentou para 86,7%, com um corte de 0,4700 milímetros de espessura da íris.Conclusões:Na amostra deste estudo, a espessura da íris demostrou-se reduzida nos olhos com ceratocone. Estes resultados sugerem que os parâmetros tomográficos podem proporcionar novas informações no auxilio da triagem de pacientes com ceratocone.