Aberraciones corneales de bajo orden en pacientes con ametropías miópicas

Objetivo: Caracterizar las aberraciones corneales de bajo orden en pacientes con ametropías miópicas. Métodos: Se realizó un estudio descriptivo, observacional y transversal, con una muestra de 104 ojos de 104 pacientes adultos con ametropías miópicas y un grupo control de 104 ojos de 104 voluntarios emétropes, que asistieron a consulta de Cirugía Refractiva del Instituto Cubano de Oftalmología. Se definieron las variables demográficas, clínicas y para la cuantificación de las aberraciones corneales la elevación-depresión y el valor cuadrático medio, aportadas mediante el mapa aberrométrico del Pentacam HR. Resultados: Hubo un predominio del sexo femenino, el rango de edad estuvo comprendido entre 18 y 39 años en ambos grupos. La mediana del equivalente esférico de los pacientes de ametropías miópicas fue -3,25 dioptrías, con agudeza visual sin corrección de 0,10, esfera de -2,63 D y cilindro de -1,00 D, 91 ojos (87,50 %) tenían astigmatismo miópico compuesto. Los valores de elevación-depresión y el valor cuadrático medio de bajo orden fueron mayores en los pacientes con ametropías miópicas que los emétropes (p< 0,001). El astigmatismo vertical, desenfoque y el astigmatismo horizontal no presentaron diferencia estadísticamente significativa entre ambos grupos. Conclusiones: La miopía con o sin astigmatismo se debe estudiar y tratar como una aberración de bajo orden. Los valores de elevación-depresión y cuadrático medio son superiores en los ojos con ametropías miópicas respecto a los emétropes.

Objective: To characterize low-order corneal aberrations in patients with myopic ametropia. Methods: A descriptive, observational and cross-sectional study was carried out with a sample of 104 eyes of 104 adult patients with myopic ametropia and a control group of 104 eyes of 104 emmetropic volunteers, who attended the Refractive Surgery Clinic of the Cuban Institute of Ophthalmology. Demographic and clinical variables were defined, and for the quantification of corneal aberrations, elevation-depression and average square value, provided by means of the Pentacam HR aberrometric map. Results: There was a predominance of female sex, the age range was between 18 and 39 years in both groups. The median spherical equivalent of myopic ametropia patients was -3.25 diopters, with uncorrected visual acuity of 0.10, sphere of -2.63 D and cylinder of -1.00 D, 91 eyes (87.50%) had compound myopic astigmatism. Elevation-depression values and low-order root average square value were higher in patients with myopic ametropes than emmetropes (p< 0.001). Vertical astigmatism, defocus and horizontal astigmatism showed no statistically significant difference between the two groups. Conclusions: Myopia with or without astigmatism should be studied and treated as a low-order aberration. The elevation-depression and average square values are higher in eyes with myopic ametropia than in emmetropic eyes.

Aberraciones corneales en pacientes con indicación de cirugía refractiva con láser de excímeros

Objetivo: Determinar las aberraciones corneales en pacientes con indicación de cirugía refractiva con láser de excímeros. Métodos: Se realizó un estudio retrospectivo, transversal, descriptivo, con 161 ojos de 81 pacientes adultos, de ambos sexos con indicación de cirugía con láser de excímeros para la corrección de su defecto refractivo. Se definieron como variables edad, sexo, desenfoque, astigmatismo, coma, trefoil y aberración esférica, las que se determinaron por el estudio topográfico de rutina con el topógrafo KeratronTM Scout, Optikon. Resultados: Se obtuvieron los siguientes valores promedios: desenfoque -4,17 ± 0,29 D (-16,15 a 8,5 D) y absoluto 4,94 ± 0,199 (10 a 16,5 D), astigmatismo -1,56 ± 0,09 D (-9,44 a -0,09 D), coma 0,25 ± 0,016 (0,01 a 1,5 D), trefoil 0,204 ± 0,016 (0,01 a 1,18 D) y aberración esférica 0,316 ± 0,018 D (0,0 a 1,27D). En el 75 % de los casos los valores absolutos de desenfoque fueron inferiores a 6,56, de astigmatismo inferior a 0,33 D, de coma menor que 0,33, trefoil inferior a 0,25 y aberraciones esféricas menores que 0,32 D. Conclusiones: Los valores promedio de las aberraciones corneales desenfoque, astigmatismo, coma, trefoil y aberración esférica se encuentran en el rango de los valores reportados en la literatura científica y la distribución de los valores de las aberraciones corneales presentan desplazamiento de la mayoría de los casos hacia los valores más bajo del rango de determinación.

Objective: To determine corneal aberrations in patients indicated for excimer laser refractive surgery. Methods: A retrospective, cross-sectional and descriptive study was carried out with 161 eyes of 81 adult patients of both sexes with indication of excimer laser surgery for the correction of their refractive defect. Age, sex, defocus, astigmatism, coma, trefoil and spherical aberration were defined as variables, determined by routine topographic study with the KeratronTM Scout topographer, Optikon. Results: The following average values were obtained: defocus of -4.17 ± 0.29 D (-16.15 to 8.5 D) and absolute of 4.94 ± 0.199 (10 to 16.5 D), astigmatism of -1.56 ± 0.09 D (-9.44 to -0.09 D), coma of 0.25 ± 0.016 (0.01 to 1.5 D), trefoil of 0.204 ± 0.016 (0.01 to 1.18 D) and spherical aberration of 0.316 ± 0.018 D (0.0 to 1.27D). In 75 % of the cases, the absolute values for defocus were lower than 6.56; for astigmatism, lower than 0.33 D; for coma, lower than 0.33; for trefoil, lower than 0.25; and for spherical aberrations, lower than 0.32 D. Conclusions: The average values of corneal aberrations for defocus, astigmatism, coma, trefoil and spherical aberration are in the range of values reported in the scientific literature, while the distribution of corneal aberrations values present displacement of most of the cases towards the lower values of the determination range.

Clinical analysis of functional optical zone after transepithelial photorefractive keratectomy in patients with different degrees of myopic astigmatism / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the effect of preoperative degrees of myopic astigmatism and anterior corneal curvature on the functional optical zone(FOZ)after transepithelial photorefractive keratectomy(TransPRK).METHODS: Retrospective study was conducted on 78 patients(130 eyes)with myopia and myopic astigmatism who underwent TransPRK, and they were divided into control group(cylinder 0D), moderate astigmatism group(-0.50～-2.00D)and high astigmatism group(&#x003E;-2.00～&#x003C;-6.00D). The FOZ was measured and compared among the three groups 6mo after operation. The correlations between attempted correction, anterior corneal curvature, corneal aberrations, Q value, and the FOZ were analyzed.RESULTS: At 6mo after operation, the mean FOZ was 5.16±0.12mm in the control group, 5.29±0.23mm in the moderate astigmatism group, and 5.49±0.23mm in the high astigmatism group(P&#x003C;0.001), and the FOZ of the high astigmatism group was significantly higher than moderate astigmatism and control group(P&#x003C;0.05, P&#x003C;0.001); Pearson correlation analysis showed that the changes in spherical equivalent, total corneal higher-order aberrations(HOAs), coma, and spherical aberration were all negatively correlated with FOZ(all P&#x003C;0.05); and FOZ positively correlated with changes in the steep curvature(K2), mean curvature(Km), corneal astigmatism, and Q value(all P&#x003C;0.01). Multiple linear regression analysis showed that there was still positive correlation between preoperative K2 and FOZ after adjusting for other risk factors(P&#x003C;0.001).CONCLUSION: Patients with high astigmatism can obtain a larger FOZ and less induced coma after TransPRK. A larger FOZ can be achieved in eyes with steeper keratometry.

Topoaberrometría en pacientes con queratocono / Topoaberrometry in patients with keratoconus

RESUMEN Objetivo: Determinar las características topoaberrométricas del queratocono. Métodos: Se realizó un estudio observacional descriptivo de corte transversal que comprendió 101 topografías corneales de pacientes diagnosticados de queratocono con el topógrafo corneal Magellan Plug and Play (n= 101 ojos), en el Instituto Cubano de Oftalmología Ramón Pando Ferrer, en el período 2016-2017. Resultados: Los grupos de edades más representados en la muestra fueron de 20-29 y de 30-39 años, con una proporción similar de pacientes en uno y otro sexo. Predominaron los pacientes con queratocono clínico por índice de severidad y con clasificación patológica según índice de predicción con correlación ascendente entre ambos índices. La localización central del cono fue la más frecuente en esta muestra, donde predominaron los valores más elevados de los índices anteriores. Predominó la aberración de alto orden coma en cuanto al valor medio de raíz cuadrática media y la aberración esférica en el valor máximo. Conclusiones: El grupo de edades más representado según la muestra analizada es el de 20 a 39 años, con proporción similar de pacientes en uno y otro sexo. Predominan los pacientes con queratocono clínico por índice de severidad y con clasificación patológica según índice de predicción con correlación ascendente entre ambos índices. La localización central del cono es la más frecuente y es donde existen los valores más elevados de los índices anteriores. Predomina la aberración de alto orden coma en cuanto al valor medio de la raíz cuadrática media y la aberración esférica en el valor máximo de esta(AU)

ABSTRACT Objective: Determine the topoaberrometric characteristics of keratoconus. Methods: A cross-sectional observational descriptive study was conducted of 101 corneal topograms of patients diagnosed with keratoconus obtained with the corneal topograph Magellan Plug and Play (n= 101 eyes) at Ramón Pando Ferrer Cuban Institute of Ophthalmology in the period 2016-2017. Results: The age groups best represented in the sample were 20-29 and 30-39 years, with a similar proportion of male and female patients. A predominance was found of patients with clinical keratoconus by the severity index and with pathological classification by the prediction index, with an ascending correlation between the two indices. Central cone location was the most frequent in the sample, with a prevalence of the highest levels of the aforementioned indices. A high frequency was found of coma higher-order aberration, according to root mean square and maximum spherical aberration values. Conclusions: The age group best represented in the study sample is 20-39 years, with a similar proportion of male and female patients. A predominance is found of patients with clinical keratoconus by the severity index and with pathological classification by the prediction index, with an ascending correlation between the two indices. Central cone location is the most frequent, with a prevalence of the highest levels of the aforementioned indices. A high frequency is found of coma higher-order aberration, according to root mean square and maximum spherical aberration values(AU)

Effect of biaxial versus coaxial microincision cataract surgery on optical quality of the cornea.

Context: Visual function is determined by a combination of the cornea, which has a larger effect and internal aberrations generated by the intraocular lens and those induced by the surgery. These corneal refractive changes are related to the location and size of the corneal incision. The smaller the incision, the lower the aberrations and the better the optical quality. Aims: To compare the effect of uneventful coaxial versus biaxial microincision cataract surgery (MICS) on the corneal aberrations. Settings and Design: Retrospective interventional nonrandomized comparative case study comprised 40 eyes of 36 patients with primary senile cataract. Subjects and Methods: They were divided into two groups: Group I (20 eyes) had operated by biaxial MICS and Group II (20 eyes) had operated by coaxial MICS. Each group were assessed by corneal topography and wavefront analysis over 6 mm pupil size preoperatively and 1‑month postoperatively. Statistical Analysis Used: Statistical analysis was performed using SPSS for Windows (version 17.0.1, SPSS, Inc.). The paired t‑test was used to compare the mean values of corneal aberrations preoperatively and 1‑month postoperatively in each group. Results: There was a significant increase in trefoil and quatrefoil in biaxial MICS (P = 0.063, 0.032 respectively) while other aberrations insignificantly changed. The coaxial MICS showed a significant increase in root mean square (RMS) of total high order aberrations (HOAs) (P = 0.02) and coma (0.028), but not the others. In comparison to each other, there was the insignificant difference as regards astigmatism, RMS of individual and total HOAs. Conclusions: Coaxial and biaxial MICS are neutral on corneal astigmatism and aberrations.