Residual aberrations resulting from cyclotorsion depend on aberrations included in the ablation and cyclotorsional error. The theoretical impact of cyclotorted ablations is smaller than that of decentered ablations or edge effects in coma and spherical aberrations. The results are valid within a single-failure condition of pure cyclotorsional errors, because no other sources of aberrations are considered. The leap from the mathematical model to the real-world outcome cannot be extrapolated without further study.

No veo con los ojos: las palabras son mis ojosOCTAVIO PAZ El ejercicio literario (del latín litterae, instrucción) implica las competencias de leer y escribir correctamente, y es una experiencia artística que involucra la creación de textos clasificados en tres géneros: poesía, ensayo y narrativa (1). Tanto en la poesía como en la narrativa, la medicina aporta recursos para su creación.La poesía es un género de la literatura en que se ofrece una perspectiva de la realidad promoviendo la estética en su lenguaje. Su origen se remonta a Egipto y Mesopotamia, en donde se han encontrado himnos religiosos. Los cantos de Homero y los Vedas le dieron continuidad a la progresiva aparición del ejercicio poético en la humanidad, hasta su esplendor definitivo en Grecia, con Hesíodo, Safo, Píndaro y Virgilio, entre otros (2).La narrativa es el ejercicio artístico de referir lingüística o visualmente una sucesión de hechos que se producen en un período y que, usualmente, resulta en un cambio de la situación inicial. Surgió, como la poesía, a partir de una tradición oral de transmisión de relatos, noticias o leyendas de pueblos primitivos. Se distingue de la poesía en el predominio del encadenamiento de los hechos en el tiempo (1,2).La creación narrativa y poética siempre ha incluido a la medicina, ya sea de manera tangencial o directa. Se sabe de cuentos, novelas o poemas inspirados en el arte de curar, algunos escritos por médi-cos, otros por pacientes y muchos más por escritores ajenos al entorno de las ciencias de la salud. Además, distintas obras literarias hablan en particular de cierta especialidad médica, ya sea la pediatría, la cirugía o la oftalmología. (3) Las distintas literaturas del mundo ofrecen exponentes con varias voces, entre las que surge la mexicana de Octavio Paz, en cuya obra también se lee la medicina.A diez años de su muerte, el escritor mexicano Octavio Paz sigue vivo en su obra. El presente ensayo es una revisión de los textos del Premio Nobel mexicano, incluidos en ¿Águila o Sol?, de 1949. En éste se rastrearon referencias a la oftalmología, como la aparición de los ojos, de cualquier procedimiento en ellos, o bien la mención de su anatomía (4).El libro ¿Águila o Sol? incluye cuentos y poemas en prosa calificados como surrealistas, en los que Paz recurrió al automatismo como método (5). Es, junto con El laberinto de la soledad y El arco y la lira, una de sus obras fundamentales. ¿Águila o sol? fue incluido dentro del libro Libertad bajo palabra, junto a los poemarios Bajo tu clara sombra, Calamidades y milagros, Semillas para un himno y La estación violenta (4).La ciencia médica ha abordado la obra de Paz escudriñando sus referencias hacia la parasitología (6). También existen análisis caracterológicos cuyo

Purpose To report keratoconus incidence in refractive surgery candidates and to compare their characteristics in scanning‐slit topography variables versus candidates with prolate corneas and a group with previous diagnosis of keratoconus. Methods All consecutive patients who underwent preoperative evaluation for refractive surgery in the last thirty‐six months were selected. Corneal scanning‐slit topography was performed in all the patients in the preoperative examination to detect patients affected by keratoconus and subjects with prolate corneas (K reading >47,2D). An additional group of keratoconic eyes was included. Age, gender, central corneal thickness (CCT), anterior best fit sphere (aBFS), posterior best fit sphere (pBFS), steepest simulated K (SSK), flattest simulated K (FSK), and irregularity index at 3 and 5mm (II3, II5) were studied. Results A total of 1662 patients (3324 eyes) were included . Ninety‐six patients (190 eyes) had a steepest K reading higher than 47,2D and among them, 10 patients (20 eyes) were identified as keratoconus (0,6%). Keratoconus group included 182 eyes. Patients with prolate corneas (PC) were older (42,95 y± 9,6) than keratoconic candidates (KC) (38,22 y±11,39)(p<0,01) and keratoconus group (KG) (35,47y±11,5)(p<0,03). aBFS was higher in PC (44,94±1,38D) than KC (43,89±1,61D)(p<0,001) and than KG (44,31±1,97D)(p<0,03). II3 and II5 was lower in PC (1,54±1,38 and 2,85±7,2) than KC (4,48±2,94 and 10,43±2,1)(p<0,001) and than KG (5,18±2,69 and 6,1±4,17)(p<0,001). CCT was higher in PC (556,04±45,07 microns) than in KC (476,95±65,45 microns)(p<0,02) and than in KG (441,63±65,04 microns)(p<0,001) Conclusion Keratoconus prevalence in refractive surgery candidates is high and has a similar profile to KG.

Purpose To cause damage to rat corneal endothelial cells in situ and determine whether exposure to red light blunts this influence. Methods Corneal endothelial cells from one eye in anesthetised rats were damaged by placing a needle in the anterior chamber and elevating the intraocular pressure (IOP, approximately 130mm Hg) for 60 minutes in the dark. In some instances the cornea was exposed to red light (2500 lux). Rats were either killed immediately or after periods of up to 15 days. Flat mounts and transverse sections of cornea were processed for the localisation of tight junctional protein ZO‐1 and JC‐1 to monitor mitochondrial health with their degree of depolarization indicated by changes in the red to green intensity of fluorescence. Results Raise IOP causes damage to the mosaic appearance of corneal endothelial cells clearly indicated by staining for ZO‐1. Exposure to red light during elevation of IOP reduced the amount of patchy damage to endothelial cells. Corneal endothelial cells appear green when stained with JC‐1 but after 60 minutes of raised IOP the cytoplasm of many cells appear red. Both the numbers and intensity of red endothelial cells increased in JC‐1 stained corneas exposed to red light. Three days after an insult of raised IOP, some red JC‐1 staining was present only in corneas exposed to red light. Conclusion Raised IOP causes damage and disruption of corneal endothelial cells. This process is blunted by red light. JC‐1 staining suggests that endothelial cell mitochondria are activated by raised IOP (presumably as a protective mechanism) and that this process is enhanced by red light.

Purpose To determine the effect of different growth factors during corneal stromal wound repair in vitro. Methods The effect of TGF‐β, FGFb and PDGF‐BB on proliferation, migration and differentiation was evaluated in human corneal keratocytes cultures. The same type of wound was performed in all cultures. After making wounds, keratocytes were cultured in different culture media: Dulbecco´s modified Eagle´s medium (DMEM/F12) or DMEM/F12 supplemented with TGF‐β, FGFb, PDGF‐BB or fetal bovine serum (FBS). Cultures were fixed after 4, 10 and 15 days, and then we studied the proliferation, differentiation and migration Results In serum‐free cultures, migration and cell proliferation rates were very low and the wounds closed after 15 days. These cells kept keratocyte morphology. The FBS addition produced fibroblast differentiation and the wounds were completely closed after 4 days. With this medium we observed the fastest rate of proliferation and cell migration of the study. TGF‐β treatment induced cell differentiation to myofibroblasts decreasing the rate of migration and cell proliferation so that the closure of the wound was very slow; 15 days after wounds performed these were not closed. Cell proliferation and migration were enhanced by FGFb and PDGF‐BB, for this reason the wounds were closed in 10 days. However both processes in PDGF‐BB supplemented cultures were more striking. Keratocytes morphology was maintained. Conclusion The effect of each growth factor signaling on keratocytes in vitro was involved in different events of wound repair, although the mixture of them in FBS improved the actions.