Sistemas genéticos para un nuevo abordaje del riesgo de progresión de la retinopatía diabética / Genetic systems for a new approach to risk of progression of diabetic retinopathy

OBJETIVO: Evaluar el riesgo de progresión de la retinopatía diabética (RD) utilizando nuevas estrategias para obtener información genética en diabéticos tipo 2 (DT2) basadas en interferencia por ácido ribonucleico (ARN). MATERIAL Y MÉTODOS: Estudio multicéntrico, prospectivo de casos-controles en 132 participantes divididos en: grupo DT2 (GDT2) con RD (+RD) y sin RD (-RD) (n = 77) y grupo control (GC) (n = 55). Tras entrevista personal y examen oftalmológico, se extrajeron lágrimas para análisis molecular (expresión de micro-ARN [miARN] [miRCURY™ ARN Isolation Kit, Qiagen]). En 18 muestras (GDT2+RD = 6; GDT2-RD = 6; GC = 6) obtuvimos librerías de 137 vs. 140 pares de bases (GeneMapper, Applied Biosystems) y realizamos secuenciación de próxima generación (NGS). El programa SPSS 15.0 vehiculizó el análisis estadístico. RESULTADOS: Edad media: 67 ± 12 años en GDT2 vs. 55 ± 21 años en GC. Distribución hombres/mujeres: 51/28 en GDT2 vs. 25/30 en GC. Los antecedentes familiares de DM, cumplir dieta, fumar, beber y realizar ejercicio mostraron diferencias significativas entre grupos (p < 0,001). Con 20-25 μL de lágrimas extrajimos 9,42 ± 3,30 ng/mL de ARN purificado, con diferencias significativas entre GDT2/GC (p = 0,002) y GDT2+RD/GC (p = 0,004). La expresión lagrimal de miARN en GDT2 correlacionó directamente con: edad/obesidad/duración de DM (p < 0,05), e indirectamente con: agudeza visual (p < 0,05). Hemos identificado 14 miARN relacionados con la presencia, mecanismos patogénicos y factores de riesgo para la progresión de la RD. CONCLUSIONES: Proponemos utilizar lágrimas como fuente de información genética para la DM. Los miARN específicos implicados en desarrollo o progresión de la RD pueden utilizarse como biomarcadores moleculares y, a partir de ellos, desarrollar futuras bioterapias

OBJECTIVE: To evaluate the risk of progression of diabetic retinopathy (DR) using new strategies to obtain genetic information in type 2 diabetes (T2D) based on interfering ribonucleic acid (RNA). MATERIAL AND METHODS: A prospective multicentre case-control study of 132 participants was distributed into: T2D with (+DR) or without (-DR) (T2DG; n = 77), and a control group (CG; n = 55). After an eye examination and personal interview, tears were collected for molecular analysis (expression of microRNAs [miRNAs] (miRCURY(TM) ARN Isolation Kit, Qiagen)]. Libraries, 137 vs. 140 bp (GeneMapper, Applied Biosystems), were obtained in 18 samples (T2DG+DR = 6; T2DG-DR = 6; CG = 6) by performing next-generation sequencing (NGS). SPSS 15.0 statistical program was used to perform data analysis. RESULTS: The mean age was 67 ± 12 years in the T2DG vs. 55 ± 21 years in the CG. Distribution men/women: 25/30 in T2DG vs. 51/28 in CG. A family history of DM, diet compliance, smoking, drinking and exercise, showed significant differences between groups (P<.001). A 20-25 microlitre sample of tears contained a mean of 9.42 ± 3.30 ng/mL of purified ARN, with significant differences between T2DG/CG (P=.002) and T2DG+RD/CG (P=.004). Tear expression of miARNs in T2DG directly correlated with age/obesity/T2D duration (P<.05), and indirectly with visual acuity (P<.05). A total of 14 miRNAs related to the presence, pathogenic mechanisms and risk factors for the progression of diabetic retinopathy, were identified. CONCLUSIONS: We propose to use tears as a source of genetic information for DM. Specific miRNAs involved in DR development and/or progression can be used as molecular biomarkers, and based on these, for developing future biotherapies

Biomarkers of lipid peroxidation in the aqueous humor of primary open-angle glaucoma patients. / Biomarcadores de peroxidación lipídica en el humor acuoso de pacientes con glaucoma primario de ángulo abierto.

OBJECTIVE: To investigate the lipid peroxidation (PEROX) processes in primary open-angle glaucoma (POAG) patients, and whether this mechanism may be related to disease progression. MATERIAL AND METHODS: A prospective, observational, cross-sectional, non-experimental, and analytical study was conducted on a case and a comparison group, consisting of 175 surgical patients divided into: 1) POAG group (GG; n=88) and 2) comparison group of patients with cataracts (CG; n=87). Demographic data, patient characteristics, lifestyle data, as well as ophthalmological examination were registered in an Excel spreadsheet. Biochemical data were obtained by processing the aqueous humor collected at the beginning of surgery. Determination of malondialdehyde/thiobarbituric acid reactive substances (MDA/TBARS) and total antioxidant activity (AAO) was assayed using enzymatic-colorimetric methods in the aqueous humor samples. Statistical analysis was performed using SPSS 15.0 software. RESULTS: Aqueous humor MDA/TBARS levels were significantly higher (P<.001) and the AAO significantly lower (P<.001) in the GG than in the GC. The MDA/TBARS directly correlated with intraocular pressure (IOP) values and the cup-to-disc ratio (CDR). Decreased AAO activity correlated inversely with IOP and CDR. Differences between groups were noticeably higher in the GG as regards obesity, alcohol consumption, anxiety, depression, and sedentary lifestyle. In the multivariate analysis, the variables that showed a better predictive ability were: MDA/TBARS, PIO, AAO, CDR, and depression. CONCLUSIONS: The POAG patients have a PEROX background that is reflected in the aqueous humor by variations in MDA/TBARS and AAO. Moreover, both the MDA/TBARS and AAO correlated with IOP values and the CDR. We propose that determination of MDA/TBARS and AAO in the aqueous humor of POAG patients can be used as biomarkers for monitoring the disease, as well the changes in lifestyle and other related risk factors.

Genetic systems for a new approach to risk of progression of diabetic retinopathy. / Sistemas genéticos para un nuevo abordaje del riesgo de progresión de la retinopatía diabética.

OBJECTIVE: To evaluate the risk of progression of diabetic retinopathy (DR) using new strategies to obtain genetic information in type 2 diabetes (T2D) based on interfering ribonucleic acid (RNA). MATERIAL AND METHODS: A prospective multicentre case-control study of 132 participants was distributed into: T2D with (+DR) or without (-DR) (T2DG; n=77), and a control group (CG; n=55). After an eye examination and personal interview, tears were collected for molecular analysis (expression of microRNAs [miRNAs] (miRCURY ™ ARN Isolation Kit, Qiagen)]. Libraries, 137 vs. 140bp (GeneMapper, Applied Biosystems), were obtained in 18 samples (T2DG+DR=6; T2DG-DR=6; CG=6) by performing next-generation sequencing (NGS). SPSS 15.0 statistical program was used to perform data analysis. RESULTS: The mean age was 67±12 years in the T2DG vs. 55±21 years in the CG. Distribution men/women: 25/30 in T2DG vs. 51/28 in CG. A family history of DM, diet compliance, smoking, drinking and exercise, showed significant differences between groups (P<.001). A 20-25 microlitre sample of tears contained a mean of 9.42±3.30 ng/mL of purified ARN, with significant differences between T2DG/CG (P=.002) and T2DG+RD/CG (P=.004). Tear expression of miARNs in T2DG directly correlated with age/obesity/T2D duration (P<.05), and indirectly with visual acuity (P<.05). A total of 14 miRNAs related to the presence, pathogenic mechanisms and risk factors for the progression of diabetic retinopathy, were identified. CONCLUSIONS: We propose to use tears as a source of genetic information for DM. Specific miRNAs involved in DR development and/or progression can be used as molecular biomarkers, and based on these, for developing future biotherapies.

Giant conjunctival squamous cell carcinoma. Treatment with surgery following topical interferon alpha-2b.

CASE REPORT: A 50-year-old man presented with a giant and invasive mass at the nasal limbus in his right eye. A surgical excision without safety margins was promptly performed, followed by interferon alpha-2b (IFNα2b) eye drops. After monitoring the patient for two years and after performing a number of biopsies, he remains free from any signs of disease. DISCUSSION: For cases of giant and invasive squamous cell carcinoma, to reverse the order of treatment, by first performing an early tumour excision, followed by the application of topical IFNα2b, may prove useful to achieve total remission of the tumour.

Análisis de factores pronósticos por tomografía de coherencia óptica de dominio espectral en el edema macular quístico pseudofáquico / Analysis of prognostic factors by spectral-domain optical coherence tomography in pseudophakic cystoid macular oedema

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Glutathione-dependent formaldehyde dehydrogenase (ADH3) and low km mitochondrial aldehyde dehydrogenase (ALDH2). New evidence for differential expression in the rat retina in response to oxidative stress.

OBJECTIVES: Epidemiological and experimental studies support the involvement of lipid peroxidation (LPO) in retinal diseases. In addition to other pathogenic mechanisms not fully understood, the possibility remains that peroxidic aldehydes, acting as cytotoxic chemicals, mediate in the progression of chronic ocular disorders. METHODS: To test proper mechanisms involved in removing peroxidic aldehydes from the retina, in an attempt to understand long-lasting changes induced by LPO, the oxidative and antioxidant enzymatic activities, as well as the retinal distribution and activity of glutathione-dependent formaldehyde dehydrogenase (ADH3) and low km mitochondrial aldehyde dehydrogenase (ALDH2), were studied and compared with induced LPO sites in the adult rat retina. Biochemical enzymatic-colorimetric assays, histochemical and immunocytochemical analyses were carried out in the mature rat retinal tissues. Statistics were performed by the SPSS 15.0 program. RESULTS: Data revealed (1) the noticeable LPO and glutathione (GSH) enzymatic system retinal and optic nerve activities; (2) the retinal expression and distribution of both the ADH3 and ALDH2; and (3) the co-localisation of iron/nicotine adenine dinucleotide phosphate (Fe/NADPH)-induced LPO, mainly in the outermost and innermost retinal strata, as compared to the rest of the retinal layers (p < 0.001). CONCLUSIONS: Changes in the GSH and GSH enzymatic system, and in the ADH3 and ALDH2 retinal expression and distribution might be crucial in assessing the intrinsic mechanisms of LPO-mediated retinopathies. Further research is needed to evaluate these findings and their application to new ophthalmological therapy.

Anatomic differences between a normal and two keratoconus corneas

Keratoconus is an anatomic deformity of the cornea characterized by progressive thinning and a cone-shaped protrusion of the central cornea. Thinning corneal disorders, such as keratoconus, should be identified before excimer laser refractive surgery.An Orbscan System (Orbscan Corneal Topography System II, Orbscan Inc., Salt Lake City, UT, USA) was used to analyse and compare corneal thickness values and the anterior and posterior corneal elevation maps of three subjects who wished to undergo excimer laser refractive surgery. The quantitative differences between the minimum thickness value of the entire cornea and the values obtained in the central and paracentral cornea of the subjects were also analysed.Analysis of corneal thicknessess revealed that normal corneas had higher central and paracentral values. Greater differences were found between the thinnest site of the entire cornea and the paracentral areas in the keratoconic corneas than in the normal cornea. Thecone-shaped protrusion was detected in the anterior and posterior corneal elevation maps of one subject but only in the posterior elevation map of the other keratoconus subject.The detection of corneal anatomic deformities,such as keratoconus, should include the analysisof corneal thickness values and the analysisof both anterior and posterior corneal elevationmaps (AU)

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Quantitative corneal anatomy in emmetropic subjects.

PURPOSE: Currently there is little information available about the corneal thickness values of healthy emmetropic subjects. Therefore, the authors decided to analyze the corneal thickness in healthy emmetropic subjects. METHODS: The authors analyzed the difference in thickness values between the thinnest corneal site and the central and paracentral cornea in 124 eyes of 124 healthy emmetropic white subjects. RESULTS: The mean difference between the thinnest site of the cornea and the thickness values obtained in the areas analyzed was as follows: 12+/-6 microm center; 140+/-19 microm superonasal; 133+/-23 microm nasal; 117+/-26 microm inferonasal; 122+/-19 microm superotemporal ; 89+/-22 microm temporal; and 99+/-29 microm inferotemporal (p<0.001; one way analysis of variance test). CONCLUSIONS: In healthy emmetropic white subjects the thinnest site of the cornea is statistically lower than the central and paracentral cornea.

[Orbscan pachymetry: differences between observers when carrying out measurements of the corneal thickness]. / Paquimetría Orbscan: diferencias entre observadores al realizar mediciones del espesor corneal.

PURPOSE: To study the corneal thickness and the inter-observer variability of corneal thickness measurements by means of Orbscan pachymetry. METHODS: We analysed the central and para-central corneal thickness of 30 subjects, whose age ranged from 19 to 38 years (mean 27.27, S.D. 5.25), with the Orbscan Topography System II (Orbscan, Inc., Salt Lake City, UT, USA). The mean of five consecutive measurements of the corneal thickness were obtained by two different observers and the results obtained were compared. RESULTS: No significant differences in mean corneal thickness between observers were found at central (p=0.749), nasal (p=0.931), supero-nasal (p=0.847), infero-nasal (p=0.930), temporal (p=0.918), supero-temporal (p=0.912) and infero-temporal (p=0.760) regions of the cornea. The maximum mean corneal thickness was found most commonly at the supero-nasal cornea (14 of 30 eyes for observer 1, and 16 of 30 eyes for observer 2). The difference between the central thickness and the maximum para-central thickness was 117 (S.D. 22) and 117 (S.D. 23) microns for observers 1 and 2 respectively (p=0.974). The difference between the central thickness and the minimum para-central thickness was 40 (S.D. 20) and 39 (S.D. 19) microns for observers 1 and 2 respectively (p=0.846). The difference between the minimum and the maximum para-central thickness was 76 (S.D. 24) and 77 (S.D. 23) microns for observers 1 and 2 respectively (p=0.895). CONCLUSIONS: Orbscan pachymetry allows central and para-central corneal studies to be carried out by different observers without any significant differences being found between them.

Paquimetría Orbscan: diferencias entre observadores al realizar mediciones del espesor corneal / Orbscan pachymetry: differences beteen observes when carrying out measurements of the corneal thickness

Objetivo: Estudiar el espesor corneal y la variabilidad entre observadores de las mediciones del espesor corneal empleando paquimetría Orbscan.Métodos: Analizamos el espesor corneal central y paracentral de 30 sujetos (n=30) cuya edad oscilaba entre 19 y 38 años (media 27,27 D.E. 5,25) con el Sistema Topográfico Orbscan II (Orbscan, Inc., Salt Lake City, UT, USA). La media de cinco mediciones consecutivas del espesor corneal fue obtenida por dos diferentes observadores. Los resultados obtenidos por los dos observadores se compararon.Resultados: No se encontraron diferencias significativas entre los valores medios del espesor corneal de los observadores en la córnea central (p=0,749), nasal (p= 0,931), superonasal (p=0,847), inferonasal (p=0,930), temporal (p=0,918), superotemporal (p=0,912) e inferotemporal (p=0,760). El máximo espesor corneal se encontró frecuentemente en la córnea superonasal (14 de 30 ojos para el observador 1, y 16 de 30 ojos para el observador 2). La diferencia entre el espesor central y el máximo paracentral fue de 117 D.E. 22 y 117 D.E. 23 micras para el observador 1 y 2 respectivamente (p=0,974). La diferencia entre el espesor central y el mínimo paracentral fue 40 D.E. 20 y 39 D.E. 19 micras para el observador 1 y 2 respectivamente (p=0,846). La diferencia entre el mínimo y el máximo espesor paracentral fue de 76 D.E. 24 y 77 D.E. 23 micras para el observador 1 y 2 respectivamente (p=0,895)Conclusiones: La paquimetría Orbscan permite realizar estudios del espesor corneal por diferentes observadores sin haber diferencias significativas entre ellos (AU)

Purpose: To study the corneal thickness and the inter-observer variability of corneal thickness measurements by means of Orbscan pachymetry. Methods: We analysed the central and para-central corneal thickness of 30 subjects, whose age ranged from 19 to 38 years (mean 27.27, S.D. 5.25), with the Orbscan Topography System II (Orbscan, Inc., Salt Lake City, UT, USA). The mean of five consecutive measurements of the corneal thickness were obtained by two different observers and the results obtained were compared. Results: No significant differences in mean corneal thickness between observers were found at central (p=0.749), nasal (p=0.931), supero-nasal (p=0.847), infero-nasal (p=0.930), temporal (p=0.918), supero-temporal (p=0.912) and infero-temporal (p=0.760) regions of the cornea. The maximum mean corneal thickness was found most commonly at the supero-nasal cornea (14 of 30 eyes for observer 1, and 16 of 30 eyes for observer 2). The difference between the central thickness and the maximum para-central thickness was 117 (S.D. 22) and 117 (S.D. 23) microns for observers 1 and 2 respectively (p=0.974). The difference between the central thickness and the minimum para-central thickness was 40 (S.D. 20) and 39 (S.D. 19) microns for observers 1 and 2 respectively (p=0.846). The difference between the minimum and the maximum para-central thickness was 76 (S.D. 24) and 77 (S.D. 23) microns for observers 1 and 2 respectively (p=0.895). Conclusions: Orbscan pachymetry allows central and para-central corneal studies to be carried out by different observers without any significant differences being found between them (AU)

Corneal endothelial cell density decreases with age in emmetropic eyes.

PURPOSE: To analyze the corneal endothelial cell density in healthy adult emmetropic subjects. METHODS: We analyzed the corneal endothelial cell density of a group made up of 225 emmetropic subjects (n=225). As age-matched control groups we analyzed two other groups, one made up of myopic subjects (n=209) and the other made up of hyperopic subjects (n=203). We recorded the mean of three consecutive measurements of the corneal endothelial cell density using the Topcon SP-2000P non-contact specular microscope (Topcon Corp., Tokyo, Japan). RESULTS: The mean age was 38.6+/-11.8 years, 40.7+/-12.2 years, and 39.2+/-10.5 years for emmetropic, myopic and hyperopic subjects respectively (p=0.994). No significant differences (p=0.920) in endothelial cell density values were found between emmetropic (2985+/-245 cells/mm2), myopic (2936+/-258 cells/mm2) and hyperopic eyes (2946+/-253 cells/mm2). Lower corneal endothelial cell density values were found in older emmetropic (p<0.001), myopic (p<0.001), and hyperopic subjects (p<0.001). A significant correlation between endothelial cell density and age was found in emmetropic (r=-0.958; p<0.001), myopic (r= -0.954; p<0.001) and hyperopic subjects (r= -0.948; p<0.001). CONCLUSIONS: In healthy emmetropic subjects there is a reduction in corneal endothelial cell density with age although there are no differences in corneal endothelial cell density values between emmetropic, myopic and hyperopic subjects.

Intraobserver reproducibility of retinal nerve fiber layer measurements using scanning laser polarimetry and optical coherencetomography in normal and ocular hypertensive subjects.

PURPOSE: To evaluate quantitatively the intraobserver reproducibility of measurements of the retinal nerve fiber layer (RNFL) in healthy subjects and an ocular hypertensive population using two nerve fiber analyzers. METHODS: Sixty eyes of normal (n=30) and ocular hypertensive subjects (n=30) were consecutively recruited for this study and underwent a complete ophthalmologic examination and achromatic automated perimetry. RNFL were measured using scanning laser polarimeter (GDx-VCC) and optical coherence tomography (OCT Model 3000). Reproducibility of the RNFL measurements obtained with both nerve fiber analyzers were compared using the coefficient of variation. RESULTS: In both groups the authors found fair correlations between the two methods in all ratio and thickness parameters. The mean coefficient of variation for measurement of the variables ranged from 2.24% to 13.12% for GDx-VCC, and from 5.01% to 9.24% for OCT Model 3000. The authors could not detect any significant differences between healthy and ocular hypertensive eyes, although in normal eyes the correlations improved slightly. Nev-ertheless, the testretest correlation was slightly better for GDx-VCC than for OCT Model 3000 (5.55% and 7.11%, respectively). CONCLUSIONS: Retinal mapping software of both nerve fiber analyzers allows reproducible measurement of RNFL in both healthy subjects and ocular hypertensive eyes, and shows fair correlations and good intraobserver reproducibility. However, in our study, GDx showed a better testretest correlation. (Eur J Ophthalmol 2004; 14: 523-30).

Intraobserver reproducibility of retinal nerve fiber layer measurements using scanning laser polarimetry and optical coherence tomography in normal and ocular hypertensive subjects.

PURPOSE: To evaluate quantitatively the intraobserver reproducibility of measurements of the retinal nerve fiber layer (RNFL) in healthy subjects and an ocular hypertensive population using two nerve fiber analyzers. METHODS: Sixty eyes of normal (n=30) and ocular hypertensive subjects (n=30) were consecutively recruited for this study and underwent a complete ophthalmologic examination and achromatic automated perimetry. RNFL were measured using scanning laser polarimeter (GDx-VCC) and optical coherence tomography (OCT Model 3000). Reproducibility of the RNFL measurements obtained with both nerve fiber analyzers were compared using the coefficient of variation. RESULTS: In both groups the authors found fair correlations between the two methods in all ratio and thickness parameters. The mean coefficient of variation for measurement of the variables ranged from 2.24% to 13.12% for GDx-VCC, and from 5.01% to 9.24% for OCT Model 3000. The authors could not detect any significant differences between healthy and ocular hypertensive eyes, although in normal eyes the correlations improved slightly. Nevertheless, the test-retest correlation was slightly better for GDx-VCC than for OCT Model 3000 (5.55% and 7.11%, respectively). CONCLUSIONS: Retinal mapping software of both nerve fiber analyzers allows reproducible measurement of RNFL in both healthy subjects and ocular hypertensive eyes, and shows fair correlations and good intraobserver reproducibility. However, in our study, GDx showed a better test-retest correlation.

[Comparative clinical study of visual results between two different types of bifocal intraocular lenses]. / Estudio clínico comparativo de los resultados visuales en dos lentes intraoculares bifocales.

PURPOSE: To compare visual results after cataract surgery in patients who underwent bilateral implantation of two different types of bifocal intraocular lenses: the model 811E (Pharmacia), and the model MF4 (Ioltech). METHODS: This prospective study comprised 99 patients who underwent phacoemulsification with bifocal IOL implantation. The model 811E was implanted in forty-seven eyes of 47 patients (group I) and the model MF4 in fifty-two eyes of 52 patients (group II). Visual acuity (distance and near), complications, and adverse events were measured. The postoperative follow-up in all patients was of 6 months. Patient satisfaction was also valued using a questionnaire. RESULTS: There was no significant difference in uncorrected distance visual acuity between both groups, which was respectively 0.63 (S.D.: 0.2) for group I and 0.58 (S.D.: 0.16) for group II (p=0.17). Nonetheless a significant difference was found when measuring corrected distance visual acuity, which was 0.86 (S.D.: 0.1) for group I and 0.77 (S.D.: 0.12) for group II (p=0.01). Mean uncorrected near visual acuity was statistically better in group I: J2.00 (S.D.:1.16) in comparison with J2.48 (S.D.:0.83) for group II (p=0.021). Subjectively, both groups indicated high levels of satisfaction, without significant difference between them, being respectively 78% (group I) and 73.4% (group II). CONCLUSIONS: Our results reveal a superiority of the bifocal diffractive lens over the refractive bifocal lens for corrected distance visual acuity and distance-corrected near visual acuity. Postoperatory complications and satisfaction degree were similar for both IOL models.

Estudio clínico comparativo de los resultados visuales en dos lentes intraoculares bifocales / Comparative clinical study of visual results between two different types of bifocal intraocular lenses

Introducción: Comparar los resultados visuales tras cirugía de cataratas con implante de dos tipos de lentes intraoculares (LIO) bifocales: el modelo 811E (Pharmacia), y el modelo MF4 (Ioltech).Métodos: Para ello realizamos un estudio prospectivo en 99 pacientes intervenidos de cataratas mediante facoemulsificación con posterior implante de LIO bifocales. En 47 pacientes se implantó el modelo 811E, y en 52 pacientes se implantó el modelo MF4. Se valoraron agudezas visuales (AV) (lejos y cerca) y refracción postoperatoria tras un periodo de seguimiento de 6 meses. La satisfacción de los pacientes se evaluó mediante un cuestionario. Resultados: No se observaron diferencias entre ambos tipos de lentes al valorar la AV para lejos sin corrección, siendo 0,63 (D.E.: 0,2) para la 811E y 0,58 (D.E.: 0,16) para la MF4 (p=0,17). Por el contrario, se observaron diferencias significativas al valorar la AV media para lejos con corrección, siendo 0,86 (D.E.: 0,1) para la 811E y 0,77 (D.E.: 0,12) para la MF4 (p=0,01), y la AV media para cerca sin corrección, siendo J2,00 (D.E.: 1,16) para la 811E y J2,48 (D.E.: 0,83) para la MF4 (p=0,021). El porcentaje de satisfacción de los pacientes fue similar en ambos tipos de LIOs, siendo respectivamente del 78 por ciento (811E) y del 73,4 por ciento (MF4).Conclusiones: Nuestros resultados muestran una superioridad de las lentes difractivas bifocales sobre las lentes refractivas bifocales en la agudeza visual corregida para lejos y en la agudeza visual de cerca con la corrección de lejos. Las complicaciones postoperatorias y el grado de satisfacción fueron similares para ambos modelos (AU)

Corneal morphometry prior to and five years after corneal stromal photoablation: the possible role of topical anesthesia on postablative corneal morphometry / Morfometría corneal previa a y cinco años tras fotoablación estromal corneal: el posible papel de la anestesia tópica en la morfometría corneal postablativa

The aim of this study was to investigate central corneal thickness values prior to and five years after ablation of the central cornea using 193 nm UV radiation. Thirty eight eyes of 38 subjects were analysed in a prospective study. Central corneal thickness measurements were carried out prior to and 60 months after corneal stromal photoablation under a 160 ?m flap with the Summit Excimed SVS plus excimer laser (Summit Technology, Inc. Walthan, MA). Mean intended ablation depth was 55±20 ?m. Central corneal thickness measurements were carried out with the DGH 2000 AP ultrasonic pachymeter (DGH Technology, Inc., San Diego, USA). Consecutive central corneal thickness readings were made until three consecutive measurements were within 5 mm of each other. The mean of these three consecutive readings was used as the value of central corneal thickness in this study. Preoperative mean central corneal thickness was 556±55 ?m; five years later it was 513.41 ?m (p<0.001). The difference between the "theoretical" postablative corneal thickness values and the "real" corneal thickness values observed 60 months after stromal photoablation was also significant (p<0.001). Five years after central corneal stromal photoablation using 193 nm UV radiation there was a disparity between the programmed postoperative residual corneal thickness and the corneal thickness obtained by ultrasound pachymetry. Further research is neccesary in order to identify possible unexpected values of corneal thickness after a paracentral corneal stromal photoablation has been carried out (AU)

El objetivo de este estudio era investigar los valores del espesor corneal previo a y cinco años tras la ablación de la córnea central empleando radiación UV de 193 nm. Treinta ojos de treinta sujetos fueron analizados en un estudio prospectivo. Las mediciones del espesor corneal se realizaron previo a y 60 meses tras la fotoablación estromal bajo un flap de 160 micras con el láser excimer Summit Excimed SVS plus (Summit Technology, Inc. Walthan, MA). La media de la ablación intentada fue de 55ñ20 micras. Las mediciones del espesor corneal central se realizaron con el paquímetro ultrasónico DGH 2000 AP (DGH Technology, Inc. San Diego, USA). Se realizaron mediciones consecutivas del espesor corneal hasta que tres consecutivas de ellas estuviesen entre 5 micras de diferencia. La media de estas tres mediciones consecutivas se usó como el valor del espesor central en este estudio. El espesor central medio era 565ñ55 micras; cinco años después era 513ñ41 micras (p<0.001). La diferencia entre los teóricos valores del espesor corneal y los verdaderos observados 60 meses tras la ablación estromal también fue significativa (p<0.001).Cinco años tras la fotoablación estromal empleando radiación UV de 193 nm existe una disparidad entre el espesor residual postoperativo programado y el espesor corneal obtenido mediante paquimetría ultrasónica. Es necesaria mayor investigación con la finalidad de identificar los posibles valores inesperados del espesor corneal tras ser realizada una ablación estromal paracentral (AU)