LASEK-mitomicina C versus PRK-mitomicina C en pacientes con miopía o astigmatismo miópico compuesto / LASEK-mitomycin C versus PRK-mitomycin C in patients with myopia or compound myopic astigmatism

RESUMEN Objetivo: Evaluar los resultados relacionados con la efectividad y la seguridad en el tratamiento con queratectomía subepitelial asistida por láser con mitomicina C versus queratectomía fotorreactiva con mitomicina C en ojos con miopía o astigmatismo miópico compuesto. Métodos: Se realizó un estudio experimental, longitudinal y prospectivo en el Instituto Cubano de Oftalmología Ramón Pando Ferrer entre abril del año 2016 y abril de 2017. Se empleó un muestreo aleatorio simple por el cual se obtuvo la técnica quirúrgica a realizar. El primer ojo operado fue el derecho y a la semana se realizó la cirugía en el ojo izquierdo, en el cual se aplicó la otra técnica quirúrgica. Esto permitió realizar en cada paciente ambas técnicas quirúrgicas. La muestra quedó constituida por 146 ojos (73 pacientes) que cumplían con los criterios de selección. Resultados: El comportamiento preoperatorio entre los dos grupos fue muy similar. En ninguno de los casos existieron diferencias en las variables que se evaluaron (agudeza visual sin corrección, agudeza visual mejor corregida, esfera, cilindro y equivalente esférico). La diferencia entre los valores preoperatorios y los encontrados a los 6 meses del tratamiento quirúrgico en cada grupo fueron estadísticamente significativos (p= 0,000) para todas las variables analizadas, excepto para la agudeza visual mejor corregida en el grupo de ojos tratados con láser con mitomicina C (p= 0,083). El haze y el defecto de epitelización fueron los dos tipos de complicaciones observadas. Conclusiones: Se demostró que ambas técnicas quirúrgicas son efectivas y seguras(AU)

ABSTRACT Objective: Evaluate the effectiveness and safety of laser-assisted subepithelial keratectomy with mitomycin C vs. photoreactive keratectomy with mitomycin C in eyes with myopia or compound myopic astigmatism. Methods: An experimental prospective longitudinal study was conducted at Ramón Pando Ferrer Cuban Institute of Ophthalmology from April 2016 to April 2017. Simple random sampling was used to decide on the surgical technique to be applied. Surgery was first performed on the right eye using one of the techniques, and then one week later on the left eye with the other technique. That way each patient could undergo both surgical techniques. The sample was composed of 146 eyes (73 patients) meeting the inclusion criteria. Results: Preoperative behavior was very similar in the two groups. In neither case were differences found in the variables analyzed (uncorrected visual acuity, best corrected visual acuity, sphere, cylinder and spherical equivalent). The differences between preoperative values and those found six months after surgery in each group were statistically significant for all the variables analyzed (p= 0.000), except for best corrected visual acuity in the group of eyes treated with laser with mitomycin C (p= 0.083). Haze and epithelization defect were the two types of complications observed. Conclusions: It was demonstrated that both surgical techniques are effective and safe(AU)

Principios para el cálculo de la lente intraocular tras cirugía refractiva corneal / Principles for the intraocular lens power calculation after corneal refractive surgery

Se estima que aproximadamente un millón o más de pacientes se realizan cirugía refractiva al año. Es por eso que con el envejecimiento son cada día más frecuentes los pacientes con catarata, a quienes previamente se les ha efectuado cirugía refractiva. El cálculo inexacto de la potencia dióptrica de la lente a implantar en la intervención de estos es también un problema de importancia creciente y con él la sorpresa refractiva. Este es mucho más complejo de lo normal, ya que existen dos fuentes de error: la incorrecta predicción de la posición efectiva de la lente por parte de la fórmula y la determinación errónea de la potencia de la córnea por parte de la queratometría. La corrección de estos dos factores permitirá realizar un cálculo correcto en estos ojos. De ahí la motivación para realizar una búsqueda actualizadas de los últimos diez años de diversos artículos publicados, con el objetivo de describir los principios para el cálculo de la lente intraocular tras cirugía refractiva corneal. Se utilizó la plataforma Infomed, específicamente la Biblioteca Virtual de Salud, con todos sus buscadores(AU)

It is considered that approximately one million or more patients undergo refractive surgery every year. Due to aging, the number of patients with cataract, who had previously undergone refractive surgery, is increasingly higher. The inaccurate calculation of the dioptric power of the lens to be implanted is also a growing significant problem and thus the refractive surprise. This is a much more complex situation since two error sources exist: the incorrect prediction of the effective position of the lens based on the formula and the wrong determination of the corneal power through keratometry. The correction of these two factors will allow making a suitable power calculation. Hence the motivation for updated search of several articles published in the last ten years, with the objective of describing the principles for intraocular lens power calculation after corneal refractive surgery. The Infomed platform, mainly the Virtual Library of Health, was fully used(AU)

Analysis of photoastigmatic keratectomy with the cross-cylinder ablation.

Aim: The aim was to evaluate the safety and efficacy of the “cross-cylinder” technique in the correction of astigmatism. Setting and Design: A prospective interventional study from a university eye department was conducted. Material and Methods: The photoastigmatic refractive keratectomy (PARK) using the “cross-cylinder” technique was performed in 102 eyes of 84 patients with at least 0.75 D of astigmatism. The study population was divided into two groups: in the first group the preoperative astigmatic power ranged from –0.75 D to –3.00 D (group 1), in the second group it ranged from –3.25 D to –6.00 D (group 2). Group 1 included 82 eyes of 67 patients (29 males and 38 females) with a mean cylinder power of –1.90 ± 0.63 D, group 2 included 20 eyes of 17 patients (13 males and 4 females) with a mean cylinder power of -4.28 ± 0.76 D. All eyes were targeted for emmetropia. The results were evaluated using Calossi's vector analysis method. Six-month postoperative outcomes are presented. Results: Six months after PARK the mean sphere for the entire cohort was +0.28 ± 0.75 D (range +2.5 to –2 D), the mean cylindrical power was +0.33 ± 0.51 D (range +2.5 to –1.25 D) and the mean spherical equivalent refraction was +0.73 ± 0.81 D (range +1.75 to –2 D). Conclusions: The cross-cylinder technique may be safely used with predictable results for the correction of astigmatism.

Effect of Base Curve Radius of Therapeutic Lenses on Epithelial Healing after Laser-Assisted Subepithelial Keratectomy

PURPOSE: To determine the effect of the base curve radius (BCR) of therapeutic soft contact lens (T-lens) on epithelial healing after laser-assisted subepithelial keratectomy (LASEK). METHODS: Ninety-two eyes in 47 patients with myopia were prospectively evaluated after LASEK. All the patients wore T-lenses with the BCR (R1) randomly chosen after LASEK. The T-lenses were removed after complete healing of the epithelial wounds. We calculated an estimated BCR (R2) from postoperative topography using a diopter conversion table. The patients were divided into two groups according to the differences between the BCR (R1) and the estimated BCR (R2). The flat fitting group was R1 > R2 (Group A), and the steep fitting group was R1R2) had 53 eyes, and Group B (R1

Effect of Base Curve Radius of Therapeutic Lenses on Epithelial Healing after Laser-Assisted Subepithelial Keratectomy

PURPOSE: To determine the effect of the base curve radius (BCR) of therapeutic soft contact lens (T-lens) on epithelial healing after laser-assisted subepithelial keratectomy (LASEK). METHODS: Ninety-two eyes in 47 patients with myopia were prospectively evaluated after LASEK. All the patients wore T-lenses with the BCR (R1) randomly chosen after LASEK. The T-lenses were removed after complete healing of the epithelial wounds. We calculated an estimated BCR (R2) from postoperative topography using a diopter conversion table. The patients were divided into two groups according to the differences between the BCR (R1) and the estimated BCR (R2). The flat fitting group was R1 > R2 (Group A), and the steep fitting group was R1R2) had 53 eyes, and Group B (R1