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)

Investigation of the Changes in Refractive Surgery Trends in Korea

PURPOSE: To evaluate changes in clinical practice in the field of refractive surgery in Korea over the past 10 years. METHODS: A survey consisting of 59 multiple-choice questions regarding the preferred types of refractive surgery, excimer laser machine, and presbyopia surgery was mailed to 742 members of the Korean Society of Cataract and Refractive Surgery in January 2016, and 50 members responded to the survey. These data were compared with the 2005 or 2007 survey results.

The Effect of Anti-glaucoma Eyedrops and 0.1% Fluorometholone on Myopic Regression after LASIK or LASEK

PURPOSE: To evaluate the effect of combined medical treatment with anti-glaucoma eyedrops and 0.1% fluorometholone on visual acuity and refractive errors in patients complaining of blurred vision due to myopic regression after laser-assisted in-situ keratomileusis (LASIK) or laser-assisted sub-epithelial keratectomy (LASEK). METHODS: This study comprised 155 patients (155 eyes) who were diagnosed with myopic regression after LASIK or LASEK and received medical treatment from January 2015 to January 2016. The visual acuity and refractive errors were compared before and after medical treatment and evaluated to determine whether the results differ between LASIK and LASEK. RESULTS: The mean time of medical treatment was 64.1 ± 36.8 months after surgery. The responder group whose vision was improved and whose myopic error was decreased after medical treatment was comprised of 63 patients (41%). Their visual acuity in this group improved -0.21 ± 0.11 logMAR, and the amount of myopic error decreased 0.56 ± 0.32 diopters. The full responder group was 24 patients (15%), and the partial responder group was 39 patients (26%). The frequency of response to medical treatment was higher after LASIK than after LASEK, but the difference was not statistically significant. CONCLUSIONS: The combined medical treatment with anti-glaucoma eyedrops and 0.1% fluorometholone was effective in 41% of patients with regard to visual acuity improvement when used for post-LASIK or post-LASEK myopic regression. The medical treatment was effective after both LASIK and LASEK.

Clinical Outcomes of an Optimized Prolate Ablation Procedure for Correcting Residual Refractive Errors Following Laser Surgery

PURPOSE: The purpose of this study was to investigate the clinical efficacy of an optimized prolate ablation procedure for correcting residual refractive errors following laser surgery. METHODS: We analyzed 24 eyes of 15 patients who underwent an optimized prolate ablation procedure for the correction of residual refractive errors following laser in situ keratomileusis, laser-assisted subepithelial keratectomy, or photorefractive keratectomy surgeries. Preoperative ophthalmic examinations were performed, and uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction values (sphere, cylinder, and spherical equivalent), point spread function, modulation transfer function, corneal asphericity (Q value), ocular aberrations, and corneal haze measurements were obtained postoperatively at 1, 3, and 6 months. RESULTS: Uncorrected distance visual acuity improved and refractive errors decreased significantly at 1, 3, and 6 months postoperatively. Total coma aberration increased at 3 and 6 months postoperatively, while changes in all other aberrations were not statistically significant. Similarly, no significant changes in point spread function were detected, but modulation transfer function increased significantly at the postoperative time points measured. CONCLUSIONS: The optimized prolate ablation procedure was effective in terms of improving visual acuity and objective visual performance for the correction of persistent refractive errors following laser surgery.

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)

Factors Affecting Long-term Myopic Regression after Laser In Situ Keratomileusis and Laser-assisted Subepithelial Keratectomy for Moderate Myopia

PURPOSE: High myopia is known to be a risk factor for long-term regression after laser refractive surgery. There have been few studies about the correction of moderate myopias that did not need retreatment after long-term follow-up. We evaluated 10 years of change in visual acuity and refractive power in eyes with moderate myopia after laser refractive surgery. METHODS: We included patients that had undergone laser in situ keratomileusis (LASIK) or laser-assisted subepithelial keratectomy (LASEK) to correct their myopia and that had at least 10 years of follow-up. We evaluated the stability of visual acuity in terms of safety, efficacy, and refractive changes at examinations 6 months and 1, 2, 5, 7, and 10 years after surgery. RESULTS: The study evaluated 62 eyes (36 eyes in LASIK patients and 26 eyes in LASEK patients). In both groups, the efficacy index tended to decrease, and it was consistently higher in the LASEK group compared to the LASIK group over the 10 years of follow-up. The safety index improved over 10 years and was always higher than 0.9 in both groups. The difference between the spherical equivalent at 6 months postoperatively and later periods was statistically significant after 5, 7, and 10 years in both groups (LASIK, p = 0.036, p = 0.003, and p < 0.001, respectively; LASEK, p = 0.006, p = 0.002, and p = 0.001, respectively). Ten years after surgery,26 eyes (66.7%) in the LASIK group and 19 eyes (73.1%) in the LASEK group had myopia greater than 1 diopter. In comparison with the thickness at 6 months postoperatively, central corneal thickness was significantly increased after 5, 7, and 10 years in both LASIK and LASEK groups (LASIK, p < 0.001, p < 0.001, and p < 0.001, respectively; LASEK, p = 0.01, p < 0.001, and p < 0.001, respectively). CONCLUSIONS: Moderately myopic eyes showed progressive myopic shifting and corneal thickening after LASIK and LASEK during 10 years of follow-up. We also found that early refractive regression may indicate the long-term refractive outcome.

Comportamiento de la cirugía refractiva con excimer laser en miopía y astigmatismo miópico / Behavior of excimer laser refractive surgery in myopia and myopic astigmatism

Los defectos de refracción pueden ser corregidos mediante lentes oftálmicos, lentes de contacto y cirugía refractiva (1). La cirugía refractiva abarca un conjunto de procedimientos quirúrgicos, los cuales modifican la anatomía del ojo para lograr la emetropía artificial (2). Las técnicas quirúrgicas corneales se clasifican en incisionales o queratotomías, actualmente en desuso, y en técnicas de ablación con láser, las cuales eliminan o reducen pequeños cambios en la curvatura corneal (3). La técnica de ablación con láser llamada Queratectomía in situ asistida por láser (LASIK) (4) ha sido el procedimiento refractivo más utilizado desde sus inicios (5). La técnica actual consiste en levantar una porción de la córnea (flap) con un microquerátomo mecánico o a través de un láser femtosegundo para posterior fotoablación y reposición del tejido (4). En la actualidad, persisten complicaciones intraoperatorias, en su mayoría por el uso del microquerátomo con una incidencia de complicaciones hasta del 33% (6), lo cual conlleva a daños en la superficie ocular, con una incidencia hasta del 5.3% (7,8). Por lo anterior otras técnicas quirúrgicas como las de superficie (PRK, LASEK Y Epi-lasik) han despertado en los últimos años mayor interés, ya que eliminan la necesidad de un colgajo corneal, lo cual disminuye la probabilidad de desestabilizar la córnea y de complicaciones graves como: infecciones, cicatrices y erosiones recurrentes. Las principales desventajas en comparación con el LASIK, son las molestias posoperatorias como el dolor y la aparición de haze corneal lo cual retarda la recuperación visual hasta que completar la epitelización corneal (9)...

Refractive errors can be corrected by ophthalmic lenses, contact lenses and refractive surgery (1). Refractive surgery encompasses a set of surgical procedures which alter the anatomy of the eye to achieve artificial emmetropia (2). Corneal surgical techniques are classified as incisional or keratotomies, currently unused, and laser ablation techniques, which eliminate or reduce small changes in corneal curvature (3). The laser ablation technique called keratectomy laser assisted in situ (LASIK) (4) has been the most widely used refractive procedure from the beginning (5). The current technique involves lifting a portion of the cornea (flap) with a mechanical microkeratome or through a femtosecond laser photoablation and subsequent replacement of tissue (4). Currently, intraoperative complications persist, mostly with the use of microkeratome complications with an incidence of up to 33% (6), which leads to damage to the ocular surface, with an incidence of up to 5.3% (7.8). Therefore other surgical like surface (PRK, LASEK and Epi-LASIK) has aroused techniques in recent years greater interest because it eliminates the need for a corneal flap, which decreases the probability of destabilizing the cornea and complications serious as infections, scars and recurrent erosions. The main disadvantages compared to LASIK, are postoperative pain and discomfort as the occurrence of corneal haze which slows visual recovery until the corneal epithelialisation (9) is completed...

Anterior segment optical coherence tomography evaluation of corneal epithelium healing time after 2 different surface ablation methods

To compare epithelial healing time following laser epithelial keratomileusis [LASEK] and photorefractive keratectomy [PRK] with anterior segment optic coherence tomography [AS-OCT]. This prospective interventional case series study comprised 56 eyes of 28 patients that underwent laser refractive surgery in the Department of Ophthalmology, Medipol University Medical Faculty, Istanbul, Turkey, between March 2014 and May 2014. Each patient was randomized to have one eye operated on with PRK, and the other with LASEK. Patients were examined daily for 5 days, and epithelial healing time was assessed by using AS-OCT without removing therapeutic contact lens [TCL]. Average discomfort scores were calculated from ratings obtained from questions regarding pain, photophobia, and lacrimation according to a scale of 0 [none] to 5. The mean re-epithelialization time assessed with AS-OCT was 3.07 +/- 0.64 days in the PRK group, 3.55 +/- 0.54 days in the LASEK group, and the difference was statistically significant [p=0.03]. Mean subjective discomfort score was 4.42 +/- 0.50 in the PRK eyes, and 2.85 +/- 0.44 in the LASEK eyes on the first exam day [p=0.001]. The score obtained on the second [p=0.024], and third day [p=0.03] were also statistically significant. The fourth [p=0.069], and fifth days scores [p=0.1] showed no statistically significant difference between groups. The PRK showed a statistically significant shorter epithelial healing time, but had a statistically significant higher discomfort score until the postoperative fourth day compared with LASEK

Incidence of Retinal Lesions before and after Refractive Surgery and Preoperative Prophylactic Laser Treatment

PURPOSE: We investigated the incidence of retinal lesions before and after surgery and the percentage of preoperative prophylactic laser treatment in patients who underwent corneal refractive surgery or phakic intraocular lens implantation (pIOLi). METHODS: The medical records of patients who underwent refractive surgery from January 2005 to June 2013 were reviewed retrospectively. We investigated the incidence and type of retinal lesions identified during the preoperative examination. Additionally, the percentage of preoperative prophylactic laser treatment and the incidence of postoperative newly developed retinal lesions were analyzed. RESULTS: A total of 894 eyes of 466 subjects (laser in situ keratomileusis [LASIK] 225 eyes, 117 subjects; laser-assisted subepithelial keratectomy [LASEK] or photorefractive keratectomy [PRK] 450 eyes, 231 subjects; pIOLi 219 eyes, 121 subjects) were enrolled in the present study. Retinal lesions were found in 268 eyes (29.98%) and of those, 144 eyes (16.11%) received prophylactic laser treatment. Postoperative newly developed retinal lesions were detected in 8 cases (LASEK or PRK, 5 cases; pIOLi, 3 cases) during the follow-up period. There was a significant correlation between preoperative spherical equivalent and the presence of retinal lesions. CONCLUSIONS: The patient population of refractive surgery is largely myopic and thus particularly vulnerable to retinal lesions. Additionally, a considerable number of patients required preoperative prophylactic laser treatment. Therefore, both surgeons and patients should be aware of the risks of developing postoperative retinal lesions.

The Incidence of Increased Intraocular Pressure when Using 0.1% Fluorometholone after Photorefractive Keratectomy

PURPOSE: To analyze the time and incidence of increased intraocular pressure (IOP) induced by 0.1% fluorometholone used to prevent corneal haze after photorefractive keratectomy (PRK). METHODS: The present study included 826 patients (826 eyes) who underwent PRK between November 2012 and October 2013 and were followed up for more than 6 months. After surgery the patients were treated with 0.1% fluorometholone for 3-6 months according to their corneal conditions. The time and incidence was analyzed with the time and incidence when anti-glaucoma eye drops were used. RESULTS: Anti-glaucoma eye drops were used in 312 eyes (38%). The anti-glaucoma eye drops were started before 4 weeks postoperatively in 105 eyes (13%) and postoperatively at 5-8 weeks in 86 eyes (10%), at 9-12 weeks in 83 eyes (10%), at 13-16 weeks in 25 eyes (3%) and after 17 weeks in 13 eyes (2%). CONCLUSIONS: The overall incidence of increased IOP when treated with 0.1% fluorometholone for 3-6 months after PRK was approximately 38%. The incidence of increased IOP in each month for the first 3 months was almost identical implying that the longer 0.1 fluorometholone was used, the higher incidence of increased IOP occurred. These results can be helpful in educating patients regarding the risk of increased IOP and determining the follow-up period after PRK.

The Incidence of Increased Intraocular Pressure when Using 0.1% Fluorometholone after Photorefractive Keratectomy

PURPOSE: To analyze the time and incidence of increased intraocular pressure (IOP) induced by 0.1% fluorometholone used to prevent corneal haze after photorefractive keratectomy (PRK). METHODS: The present study included 826 patients (826 eyes) who underwent PRK between November 2012 and October 2013 and were followed up for more than 6 months. After surgery the patients were treated with 0.1% fluorometholone for 3-6 months according to their corneal conditions. The time and incidence was analyzed with the time and incidence when anti-glaucoma eye drops were used. RESULTS: Anti-glaucoma eye drops were used in 312 eyes (38%). The anti-glaucoma eye drops were started before 4 weeks postoperatively in 105 eyes (13%) and postoperatively at 5-8 weeks in 86 eyes (10%), at 9-12 weeks in 83 eyes (10%), at 13-16 weeks in 25 eyes (3%) and after 17 weeks in 13 eyes (2%). CONCLUSIONS: The overall incidence of increased IOP when treated with 0.1% fluorometholone for 3-6 months after PRK was approximately 38%. The incidence of increased IOP in each month for the first 3 months was almost identical implying that the longer 0.1 fluorometholone was used, the higher incidence of increased IOP occurred. These results can be helpful in educating patients regarding the risk of increased IOP and determining the follow-up period after PRK.

Surface Ablation with 0.02% Mitomycin C for Retreatment after LASIK and LASEK

PURPOSE: To evaluate the efficacy and safety of surface ablation with mitomycin C (MMC) for the retreatment of refractive errors following laser-assisted in-situ keratomileusis (LASIK) and laser-assisted sub-epithelial keratectomy (LASEK). METHODS: In this retrospective clinical study conducted at a single center, we evaluated 23 eyes that received surface ablation with MMC (0.02%, 20 seconds) between 2009 and 2013 for the treatment of residual refractive errors following myopic LASIK and LASEK. All eyes were evaluated for corneal thickness, initial refractive error, time interval to retreatment, amount of retreatment, duration of postoperative topical steroids use as well as uncorrected vision, spherical equivalent and corneal haziness preoperatively and 1, 3, 6 and 12 months postoperatively. RESULTS: Initially corrected myopia in the LASIK group was -6.47 +/- 2.17 D and -5.68 +/- 2.51 D in the LASEK group. Mean time between initial and retreatment by surface ablation was 11.88 +/- 5.59 months for LASIK and 14.07 +/- 10.10 for LASEK. Retreat amount was 1.49 +/- 0.36 D after LASIK and -1.65 +/- 0.41 D after LASEK. At postoperative 12 months, uncorrected visions were -0.061 +/- 0.886 (log MAR) in the LASIK group and -0.004 +/- 0.745 (log MAR) in the LASEK group and spherical equivalents were -0.55 +/- 0.56 D in the LASIK group and 0.36 +/- 0.33 D in the LASEK group. Postoperative hazes developed in 1 of 8 LASIK eyes and 3 of 15 LASEK eyes which resolved with application of topical steroid for 2-3 months postoperatively. CONCLUSIONS: Surface ablation with 0.02% MMC is safe and highly effective for treating myopic regression following LASIK or LASEK. Application of 0.02% MMC for 20 seconds was effective in preventing postoperative haze formation and maintaining stable vision and spherical equivalent at 12 months after retreatment.

Surface Ablation with 0.02% Mitomycin C for Retreatment after LASIK and LASEK

PURPOSE: To evaluate the efficacy and safety of surface ablation with mitomycin C (MMC) for the retreatment of refractive errors following laser-assisted in-situ keratomileusis (LASIK) and laser-assisted sub-epithelial keratectomy (LASEK). METHODS: In this retrospective clinical study conducted at a single center, we evaluated 23 eyes that received surface ablation with MMC (0.02%, 20 seconds) between 2009 and 2013 for the treatment of residual refractive errors following myopic LASIK and LASEK. All eyes were evaluated for corneal thickness, initial refractive error, time interval to retreatment, amount of retreatment, duration of postoperative topical steroids use as well as uncorrected vision, spherical equivalent and corneal haziness preoperatively and 1, 3, 6 and 12 months postoperatively. RESULTS: Initially corrected myopia in the LASIK group was -6.47 +/- 2.17 D and -5.68 +/- 2.51 D in the LASEK group. Mean time between initial and retreatment by surface ablation was 11.88 +/- 5.59 months for LASIK and 14.07 +/- 10.10 for LASEK. Retreat amount was 1.49 +/- 0.36 D after LASIK and -1.65 +/- 0.41 D after LASEK. At postoperative 12 months, uncorrected visions were -0.061 +/- 0.886 (log MAR) in the LASIK group and -0.004 +/- 0.745 (log MAR) in the LASEK group and spherical equivalents were -0.55 +/- 0.56 D in the LASIK group and 0.36 +/- 0.33 D in the LASEK group. Postoperative hazes developed in 1 of 8 LASIK eyes and 3 of 15 LASEK eyes which resolved with application of topical steroid for 2-3 months postoperatively. CONCLUSIONS: Surface ablation with 0.02% MMC is safe and highly effective for treating myopic regression following LASIK or LASEK. Application of 0.02% MMC for 20 seconds was effective in preventing postoperative haze formation and maintaining stable vision and spherical equivalent at 12 months after retreatment.

Clinical Efficacy of Topical Diquafosol Tetrasodium after Laser Epithelial Keratomileusis

PURPOSE: To evaluate the clinical effectiveness of topical diquafosol tetrasodium (DQS) after laser epithelial keratomileusis (LASEK). METHODS: This randomized prospective study included 97 eyes of 49 patients who were scheduled for LASEK. Patients in the DQS group used both 0.3% sodium hyaluronate and 3% DQS for 3 months after surgery while patients in the control group used only 0.3% sodium hyaluronate. Corneal staining score, tear film break-up time (TF-BUT), Schirmer test and ocular surface disease index (OSDI) were evaluated before surgery and 2, 4, 8, 12 and 16 weeks after surgery. RESULTS: There was no significant difference in visual acuity, spherical equivalent and corneal haziness between the 2 groups after surgery. Corneal staining score was significantly lower in the DQS group than in the control group 2 weeks after LASEK (p < 0.01) and increased in the control group after LASEK compared with the preoperative value (2 weeks after LASEK, p < 0.01), but decreased in the DQS group (12 and 16 weeks after LASEK, p < 0.05). TF-BUT was significantly higher in the DQS group than in the control group 2 to 16 weeks after LASEK (p < 0.01) and increased values were observed in the DQS group after LASEK compared with the preoperative value (4 to 16 weeks after LASEK, p < 0.05). The mean OSDI was significantly higher 4 to 16 weeks after LASEK in the control group than in the DQS group (p < 0.01). CONCLUSIONS: Subjective dry eye symptoms and objective markers were worse for 4 weeks after LASEK. The use of 3% DQS for 12 weeks after surgery improved these symptoms and markers with the effect lasting 16 weeks after LASEK.

Short-Term Clinical Results of Hyperopic LASEK in Korean Patients

PURPOSE: To evaluate short-term clinical outcomes following hyperopic laser-assisted subepithelial keratomileusis (LASEK) in Korean patients. METHODS: This retrospective study included 18 eyes of 10 patients who underwent hyperopic LASEK between May 2005 and March 2013 in Seoul National University Hospital. Visual acuity and spherical equivalent were evaluated preoperatively and at 1 and 3 months postoperatively. High order aberrations and contrast sensitivity were measured before and 3 months after the operation. Alternative prism cover test (APCT) was performed both preoperatively with correction and postoperatively without correction. RESULTS: The mean age of patients was 32 +/- 11 years and the mean spherical equivalent refractive error was -2.95 +/- 1.24 diopters (D). Uncorrected visual acuities were log MAR +0.17 +/- 0.15 and log MAR +0.14 +/- 0.15 at postoperative 1 month and 3 months, respectively and showed no significant difference in best corrected visual acuity (+0.25 +/- 0.30). Spherical equivalent was -0.22 +/- 1.22 D at 1 month and 0.38 +/- 0.91 D at 3 months postoperatively. In 6 patients who had esotropia before the operation, APCT was 7.83 +/- 3.60 prism diopters (PD) esotropia at distance with correction preoperatively and 4.67 +/- 5.65 PD at distance without correction postoperatively. Three patients (16.7%) showed delayed wound healing with 1 (5.56 %) having persistent corneal opacity without significant visual loss. CONCLUSIONS: The effect of LASEK may be comparable for correcting hyperopia and esotropia when compared with the effect of LASIK in previous reports; however, delayed wound healing may be a concern.

Clinical Outcome of Retreatment after Refractive Surgery

PURPOSE: To evaluate the clinical outcome of retreatment after refractive surgery. METHODS: Retrospective analysis of 38 eyes of 24 patients who received retreatment surgery after refractive surgery from August 2008 to May 2013 was performed. Pre-initial surgery characteristics and the reason for retreatment were investigated, and preand post-retreatment uncorrected visual acuity, best corrected visual acuity, safety index, efficacy index, predictability, and postoperative complication were also investigated. RESULTS: Age at initial refractive surgery and retreatment were 28.50 +/- 7.29 years (17-49 years) and 31.21 +/- 6.49 years (21-49 years). Reasons for retreatment were myopic regression in 36 eyes (94.7%) and overcorrection in two eyes (5.3%). Methods of retreatment were laser subepithelial keratomileusis (LASEK) in 31 eyes (81.6%) and laser-assisted in situ keratomileusis (LASIK) in seven eyes (18.4%). Safety index values for all were above 1.0 and efficacy index values were 0.92, 0.93, and 0.95 in postoperative examination at 1 month, 3 months, and 6 months, respectively. No eye showed a decrease in best corrected visual acuity. One eye had transient hyperopia after retreatment, and two eyes had postoperative corneal opacity, but no eye experienced significant alteration in visual prognosis. CONCLUSIONS: Retreatment after refractive surgery was an efficient and safe clinical course in our clinic. No long-term complications were observed, and uncorrected visual acuity and refractive errors significantly improved after retreatment. In particular, LASEK can be considered as a safe and efficient retreatment modality without risk of keratectasia.

Técnica de superficie (LASEK) en pacientes con alta miopía / Surface technique (LASEK) in patients with high myopia: en

Introducción: actualmente, uno de los grandes retos de la oftalmología es hallar el tratamiento idóneo para los pacientes con miopía elevada. Objetivo: identificar la línea evolutiva de estos afectados de acuerdo con los resultados visuales y la presencia de complicaciones posoperatorias. Métodos: se realizó un estudio descriptivo, longitudinal y retrospectivo de 22 pacientes (33 ojos) con miopía alta, entre -6,00 y -10,00 dioptrías, atendidos en el Servicio de Cirugía Refractiva del Centro Oftalmológico del Hospital General Docente "Enrique Cabrera" de La Habana, operados mediante la técnica de superficie LASEK desde enero del 2010 hasta junio del 2011. Resultados: predominaron el grupo etario de 20-29 años (54,5 %), las féminas (72,7 %) y el haze (45,5 %) como complicación posoperatoria. La mayoría de los pacientes (97,0 %) alcanzaron agudeza visual con corrección (entre 0,6 y 1,0) en el periodo posoperatorio; 60,6 % con equivalente esférico (entre -1,00 y 0,25 dioptrías) y 69,7 % con valores queratométricos de 39,05- 43,00 dioptrías. Conclusiones: el LASEK resultó efectivo en la corrección de la miopía alta, no exento de complicaciones, pero sin repercusión en la visión final alcanzada y en el grado de satisfacción después del proceder.

Introduction: at present, one of the great challenges of ophthalmology is to find the adequate treatment for the patients with high myopia. Objective: to identify the clinical course of these affected patients according to the visual results and the presence of postoperative complications. Methods: A descriptive, longitudinal and retrospective study of 22 patients (33 eyes) with high myopia, between -6,00 and -10,00 diopters, assisted in the Service of Refractive Surgery of the Ophthalmological Center from "Enrique Cabrera" Teaching General Hospital in Havana, operated by means of the LASEK surface technique was carried out from January, 2010 to June, 2011. Results: the age group 20-29 years (54.5%), the female sex (72.7%) and the haze (45.5%) as postoperative complication prevailed. Most of the patients (97.0%) reached a visual acuity with correction (between 0.6 and 1.0) in the postoperative period; 60.6% with spherical equivalent (between -1.00 and 0.25 diopters) and 69.7% with queratometric values of 39,05 - 43,00 diopters. Conclusions: the LASEK was effective in the correction of high myopia, with certain complications, but without negative result in the final vision reached and in the satisfaction after the procedure.

Current management of presbyopia

Presbyopia is a physiologic inevitability that causes gradual loss of accommodation during the fifth decade of life. The correction of presbyopia and the restoration of accommodation are considered the final frontier of refractive surgery. Different approaches on the cornea, the crystalline lens and the sclera are being pursued to achieve surgical correction of this disability. There are however, a number of limitations and considerations that have prevented widespread acceptance of surgical correction for presbyopia. The quality of vision, optical and visual distortions, regression of effect, complications such as corneal ectasia and haze, anisometropia after monovision correction, impaired distance vision and the invasive nature of the currently techniques have limited the utilization of presbyopia surgery. The purpose of this paper is to provide an update of current procedures available for presbyopia correction and their limitations

Higher Order Aberrations of the Corneal Surface after Laser Subepithelial Keratomileusis

PURPOSE: To evaluate the changes of higher order aberrations (HOAs) before and after laser subepithelial keratomileusis (LASEK) and to analyze the influence of tear film instability on HOAs of the corneal surface after LASEK. METHODS: In this cross-sectional study, 31 patients who underwent LASEK were divided into dry eye (16 patients, 32 eyes) and non-dry eye groups (15 patients, 30 eyes). Uncorrected distance visual acuity, spherical equivalent refraction, ablation depth, tear film parameters and Ocular Surface Disease Index (OSDI) questionnaire scores were evaluated in both groups. Total HOA root mean square (RMS), third-order coma, third-order trefoil and fourth-order spherical aberration (SA) of the corneal surface immediately and at 10 seconds after blinking were measured before and after surgery. RESULTS: The total HOA RMS, coma, trefoil and SA significantly increased after LASEK compared with preoperative values in both groups. In the dry eye group, total HOA RMS, coma and trefoil significantly increased except for SA at 10 seconds after blinking compared with those measured immediately after blinking. In addition, the changes of total HOA RMS, coma and trefoil were negatively correlated with tear film break-up time (R = -0.420, -0.473 and -0.439, respectively), but positively correlated with OSDI score (R = 0.433, 0.499 and 0.532, respectively). In the non-dry eye group, there were no significant differences between HOAs measured at 10 seconds after blinking and those measured immediately after blinking. CONCLUSIONS: The HOAs including coma, trefoil and SA significantly increased after LASEK. The tear film instability in the dry eye can be associated with more deterioration of the optical quality after LASEK, due to more significant increase of total HOA RMS, coma and trefoil.

Transient Myopic Shift Due to Increased Latent Accommodation after LASEK

PURPOSE: To investigate accommodation and progress of patients who showed myopia on manifest refraction in the early postoperative period after LASEK. METHODS: Forty-one eyes were included in the present study which had undergone LASEK surgery from February to March 2012. Seven eyes showed myopia over -0.25 D on manifest refraction at 1 month postoperatively, but showed decreased amount of myopia at 2 months postoperatively and were classified as group 1. The other 34 eyes were classified as group 2. The differences between cycloplegic and manifest refraction (CRSE-MRSE) were defined as the amount of latent accommodation and compared between the 2 groups. RESULTS: Amount of latent accommodation was 0.179 +/- 0.426 D in group 1 (7 eyes), 0.265 +/- 0.303 D in group 2 (34 eyes) preoperatively, 1.286 +/- 0.664 D in group 1, 0.368 +/- 0.536 D in group 2 at 1 month postoperatively, and 0.500 +/- 0.520 D in group 1, and 0.489 +/- 0.546 D in group 2 at 2 months postoperatively. The amount of latent accommodation in group 1 was significantly greater than that of group 2 one month postoperatively. As the amount of latent accommodation decreased, the amount of myopic shift decreased gradually over 2 months in group 1 after surgery. CONCLUSIONS: Transient myopic shift due to increased latent accommodation was observed in several patients one month postoperatively and the amount of myopic shift decreased with time without treatment. Thus, surgeons should consider cycloplegic refraction when planning treatment for patients with myopic regression.