Piggyback corneal como alternativa en el tratamiento del queratocono / Corneal Piggyback as an Alternative in the Treatment of Keratoconus

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

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

Phacoemulsification, pinhole pupilloplasty, and pre-Descemet抯 endothelial keratoplasty for keratoconus with Fuchs� endothelial dystrophy

The comorbidity of keratoconus with Fuchs� endothelial dystrophy with cataract is a rare clinical combination. We present an amalgamation of surgical techniques to manage the above clinical conditions and its complications in single setting. The modified triple procedure, namely, the phacoemulsification, pinhole pupilloplasty, and pre-Descemet抯 endothelial keratoplasty (PDEK) in the order of description is followed in single sitting. Lens removal by phacoemulsification, correction of irregular astigmatism by pinhole pupilloplasty (pinhole optics), and exchanging the endothelial layer for PDEK forms the main segments of the triple procedure. This combination of techniques may decrease the risk of multiple surgeries and its related complications. Moreover, it will allow the patient for faster visual rehabilitation by improving the uncorrected visual acuity and visual quality.

Lentes esclerales: características e indicaciones / Scleral lenses: characteristic and indications

Los lentes de contacto esclerales o de apoyo escleral constituyen una de las opciones terapéuticas más relevantes en el tratamiento y corrección óptica de las enfermedades corneales primaria o secundarias, que traen como consecuencia alteraciones de la curvatura, de la regularidad de la superficie y de su transparencia. La evolución y el desarrollo de este tipo de lentes han abierto un diapasón de múltiples opciones para su uso. En la actualidad se prescriben por numerosos especialistas y ópticas del mundo con una gran aceptación y confort de los pacientes que los utilizan, lo que ha popularizado su comercialización. Realizamos una búsqueda de diversos artículos publicados en los últimos diez años para profundizar en el conocimiento de las características e indicaciones de los lentes de contacto esclerales(AU)

Scleral contact lenses or sclera support lenses are one of the most relevant therapeutic options in the treatment and optical correction of primary or secondary corneal diseases which result in alterations in the curvature, the regularity of surface and transparency. The development of this type of lenses has opened up a range of multiple options for their use. Nowadays, many specialists and optical centers worldwide prescribe them, with a great deal of acceptance by and comfort for the patients using them, and their marketing has become popular. A search of several articles published in the last ten years was made to expand the knowledge about the characteristics of and indications for the sclera contact lenses(AU)

Loss of Best Corrected Visual Acuity after LASIK

Loss of best corrected visual acuity(BCVA)is a landmark of safety, as one of important complications of refractive surgery. To evaluate causes of 2 lines or more loss of BCVA after laser in situ keratomileusis(LASIK), 206 eyes of 139 patients, who had undergone LASIK and had been followed up for 6 months or more, were included in this study. During the follow-up, nineteen eyes(9.2%, 19/206)showed 2 lines or more loss of BCVA postoperatively. The causes of BCVA were irregular astigmatism(15 eyes, 7.3%), retinal complications(3 eyes, 1.5%), and infectious keratitis(1 eye, 0.5%). All irregular astigmatisms had occured within 1 month postoperatively and 13 eyes of all 15 eyes spontaneously recovered after postoperative 3 months. The persistent loss of BCVA occurred in 5 eyes(2.4%, 5/206). Three cases of all 5 persistent losses of BCVA were due to retinal complications. In conclusion, our results suggest that the most common cause of loss of BCVA after LASIK is irregular astigmatism. Irregular astigmatism is a temporary situation which has a tendancy of spontaneous recovery. Thus careful observation is recommended in irregular astigmatism after LASIK. The retinal complications of LASIK may lead to permanent loss of BCVA. Therefore it is needed to examine preoperative fundus closely and to explain possible postoperative complicaitons to the patients and their family.

A Case of Unilateral Pellucid Marginal Corneal Degeneration Diagnosed by Computerized Topography

Pellucid marginal degeneration is a noninflammatory peripheral corneal thining disorder, which progresses slowly, affects inferior cornea bilaterally, occurs usually between twenties and fifties. Protrusion of the cornea with normal corneral thickness occurs above a band of thinning which is located 1 to 2mm from the limbus and measures 1 to 2mm in width and the patient complaints of progressive visual disturbance due to high irregular astigmatism. Topographically, the lowest corneal power is located along a narrow corridor of the central and peracental cornea and corneal power is highest along the inferior peripheral cornea and in the mid-peripheral cornea along the inferior oblique corneal meridian in a band-like fashion and is decreased slowly superior to that meridian. We experienced a case of pellucid marginal degeneration who had a history of progressive visual loss due to high irregular astigmatism. A 67 year-old woman had the characteristic topographic pattern and clinical feature of pellucid marginal degeneration only in her righ eye and we report it as the first case of unilateral pellucid marginal degeneration in Korea.

A Case of Unilateral Pellucid Marginal Corneal Degeneration Diagnosed by Computerized Topography

Pellucid marginal degeneration is a noninflammatory peripheral corneal thining disorder, which progresses slowly, affects inferior cornea bilaterally, occurs usually between twenties and fifties. Protrusion of the cornea with normal corneral thickness occurs above a band of thinning which is located 1 to 2mm from the limbus and measures 1 to 2mm in width and the patient complaints of progressive visual disturbance due to high irregular astigmatism. Topographically, the lowest corneal power is located along a narrow corridor of the central and peracental cornea and corneal power is highest along the inferior peripheral cornea and in the mid-peripheral cornea along the inferior oblique corneal meridian in a band-like fashion and is decreased slowly superior to that meridian. We experienced a case of pellucid marginal degeneration who had a history of progressive visual loss due to high irregular astigmatism. A 67 year-old woman had the characteristic topographic pattern and clinical feature of pellucid marginal degeneration only in her righ eye and we report it as the first case of unilateral pellucid marginal degeneration in Korea.

The causes of Unsatisfactory Unaided visual Acuity after Exximer Laser PRK for Myopia

we analyzed data from 102 patients(152 eyes) who underwent photorefractive keratectomy to investigate the postoperative causes of unsatisfactory unaided visual acuity. A VISX 20/20 exicimer laser(VISX, Inc, Santa Clara, DA USA, version 4. 01) was used in all cases by one surgeon(J.W.H). The patients who showed unsatisfactory unaided vision, less than 20/40 uncorrected visual acuity, with minimal follow-up periods of 6 months were included. A decreased unaided visual acuity was detected in 20 eyes(13%). Range of preoperative myopia was -2.50 to -14.00 diopters. Mean postoperative uncorrected visual acuity(geometric mean)was 0.33+/-0.12 and mean corrected visual acuity was 0.83 +/-0.25. Multiple factors contributed to unsatisfactory unaided vision; myopic regression in 8 eyes, irregular astigmatism in 4 eyes, overcorrection in 1 eye, severe corneal opacity in 1 eyes(2.6%) and the causes were as follows; irregular astigmatism, decentration combined with central island and severe corneal opacity. In conclusion, refractive results after photorefractive keratectomy were reasonably predictable and stable, but some sight threatening complications occured in a minority eyes. Improved techniques such as centering procedures and improved excimer laser program will be essential to prevent unsatisfactory unaided vision.

The Correction of Corneal Astigmatism Using Piggyback Contact Lens

We evaluated the effects of piggyback contact lens that override the hard contact lens over soft contact lens for irregular astigmatic correction. Two patients received corneal suture for corneal laceration and one patient received penetrating keratoplasty for Francois dystrophy. The uncorrected visual acuity was counting fingers at 20cm, 0.05, and 0.08, respectively and corrected visual acuity using glasses or conventional contact lens was 0.1, 0.2, and 0. 2, respectively. The difference of keratometry reading between two meridians is 6, 7.5, and 12.5 diopters, respectively. The visual acuity after piggyback contact lens fitting was 0.4, 0.9, and 0.3, respectively. The complication such as corneal ederna, corneal erosion, and neovascularization of cornea was not noted during 24 months after piggyback contact lens fitting. The piggyback contact lens fitting inay be an effective method of correcting visual acuity for irregular astigmatism.