Effect of contact lens wear on the anatomic values of the corneal thickness

The aim was to analyze the changes in centralcorneal thickness values due to soft contact lens wear. We analyzed the central corneal thickness values (baseline measurements) of 15 myopic adolescent soft contact lens wearers (15 eyes; aged 15 to 16 years old). Three years later, the central corneal thickness wasmeasured again. We also measured the central corneal thickness of 31 myopic adolescents who did not use contact lenses (31 eyes; aged 15 to 16 years old) and 34 myopic contact lens wearers aged between 25 and 40 yearsold (34 eyes). We obtained the mean of fivemeasurements using the Orbscan Topography System II (Orbscan, Inc., Salt Lake City, UT,USA). In the later measurements (three years)there was a significant decrease in the central corneal thickness values (p=0.012) of the adolescent contact lens wearers and the contact lens subjects aged 25 to 40 years old(p<0.001). This decrease was not found in theadolescent non-contact lens wearers (p=0.476). The central corneal thickness values of the adolescent contact lens wearers were significantly lower than the baseline values up to four weeks after removal of theircontact lenses (p=0.201). In conclusion, therewas a significant reduction in the anatomic values of corneal thickness associated with soft contact lens wearers, although baseline thickness values recovered to normal levels approximately one month after the use of contact lenses had ceased (AU)

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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 ocular anatomy in vivo: comparison of axial length and anterior chamber depth values obtained by a single observer by means of optical biometry and immersion and applanation ultrasound biometry

The aim of the present work was to analyzeand compare axial length and anterior chamberdepth values obtained by means of IOLMaster™, immersion and applanationultrasound. Axial length and the anteriorchamber depth measurements were carriedout by a single observer in 30 volunteers(n=30; mean age, 68±10.7 years of age; range44 to 83 years) using IOLMaster™ (ZeissHumphrey System, CA, USA), immersion andapplanation ultrasound biometry. Ultrasoundmeasurements were carried out with the CompuscanA-B Storz (San Louis, MO, USA). TheIOLMaster™ provided axial length measurementsthat were 0.04 mm (p=0.936) and 0.13mm (p=0.606) higher than those fromimmersion and applanation ultrasound respectively.The mean difference between the opticaland applanation measurements was -0.11mm, and -0.03 mm between the optical andimmersion measurements. In conclusion,there are no significant differences betweenIOLMaster™, immersion and applanationultrasound axial length and anterior chamberdepth values (AU)

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Morphometric differences between normal and dry eyes

The aim of the study was to quantify the anatomicdifferences in central corneal thickness, anteriorocular chamber depth, lens thickness, vitreouschamber depth, and ocular axial length betweennormal and dry-eyes. Central corneal thickness(CCT), ocular anterior chamber depth (ACD), lensthickness (LT), vitreous chamber depth (VCD)and ocular axial length (AL) were measured in 70normal subjects and in 58 subjects with dry-eyes.Central corneal thickness was measured withscanning-slit corneal topography while ocularanterior chamber depth, lens thickness, vitreouschamber depth and ocular axial length were measuredwith applanation ultrasound biometry.Central corneal thickness was 0.558±0.30 mmand 0.532±0.34 mm in normal and dry-eyes,respectively (p<0.001). Mean ocular anteriorchamber depth was 3.17±0.23 mm and 2.93±0.35mm in normal and dry-eyes, respectively(p=0.002). Lens thickness was 4.49±0.42 mm inthe dry-eye patients and 4.71±0.32 mm in thenormal subjects (p=0.022). Vitreous chamberdepth was 16.75±1.75 mm and 15.54±1.34 mm innormal and dry-eyes, respectively (p=0.001).Ocular axial length was 24.58±1.73 in normalsubjects and 23.07±1.48 in dry-eye subjects(p<0.001). We conclude that quantitative ocularanatomy values are lower in dry-eye subjects (AU)

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Quantitative central corneal anatomy and anaesthetic eye drops effects: Comparison between 0.4% oxybuprocaine and a combination of 0.1% tetracaine and 0.4% oxybuprocaine

We aimed to analyse the changes in central cornealthickness values following the instillation of0.4% oxybuprocaine eye drops and following acombination of 0.1% tetracaine and 0.4% oxybuprocaineeye drops.Orbscan pachymetry (Orbscan II CornealTopography System; Orbscan, Inc., Salt LakeCity, UT, USA) was carried out before andthree minutes after the instillation of 0.4% oxybuprocaineeye drops, and before and threeminutes after the instillation of a combinationof 0.1% tetracaine and 0.4% oxybuprocaine eyedrops in 35 healthy subjects (n=35; aged 20-30years). After the instillation of 0.4% oxybuprocaineeye drops there was a mean increase incentral corneal thickness of 25±11 microns.After the combination of 0.1% tetracaine and0.4% oxybuprocaine eye drops it rose to 48±20microns. The combination of 0.1% tetracaineand 0.4% oxybuprocaine anaesthetic eye dropscauses higher increases in central cornealthickness values than 0.4% oxybuprocaine eyedrops (AU)

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Gender differences in corneal thickness values

The aim was to study gender differences in corneal thickness. We analysed the corneal thickness of 100 corneas of 100 healthy subjects (mean age 30.87±7.76 years; range, 19 to 54 years old) with the Orbscan Topography System II (Orbscan, Inc., Salt Lake City, UT. USA). The means of five consecutive measurements of the central and paracentral corneal thickness were obtained. No significant differences in mean corneal thickness between women and men at central (p=0.477), nasal (p=0.247), superonasal (p=0.242), inferonasal (p=0.554), temporal (p=0.538), superotemporal (p=0.524) and inferotemporal (p=0.860) corneal locations were found. In sum, there are no differences in mean central and paracentral corneal thickness values between women and men (AU)

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The effect of a combination of 0.1% tetracaine HCl and 0.4% oxybuprocaine HCl on human central corneal thickness measurements

A combination of 0.1% tetracaine HCl and 0.4% oxybuprocaine HCl is used when carrying out morphometrical corneal studies in vivo by means of ultrasound pachymetry. The aim of this was to determine the effect of a combination of 0.1% tetracaine HCl and 0.4% oxybuprocaine HCl anesthetic eye drops on central corneal thickness values. We carried out a prospective study involving 30 eyes of 30 healthy subjects. The mean age of the subjects was 26.13±2.62 years (age ranged from 20 to 30 years old). Central pachymetry was carried out prior to and three minutes after the instillation of two saline solution eye drops, and three minutes after the administration of a combination of 0.1% tetracaine HCl and 0.4% oxybuprocaine HCl anesthetic eye drops. The mean of three consecutive measurements of the central corneal thickness obtained with the Orbscan Topography System II (Orbscan, Inc., Salt Lake City, UT. USA) was used as the corneal thickness value. No significant differences were found (p=0.714) in the mean central corneal thickness values before and three minutes after saline solution eye drops had been instilled. Nevertheless, after anesthesia there was a significant increase in mean central corneal thickness (p<0.001). Increases ranged from 22 to 131 micrometers, with a mean of approximately 47 micrometers. Following the instillation of a combination of 0.1% tetracaine HCl and 0.4% oxybuprocaine HCl eye drops corneal thickness increase. Researchers must be aware of this effect of topical anesthetic eye drops on corneal morphometry in order to analyze corneal thickness results correctly (AU)

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Human corneal thickness using a noncontact specular microscope

The aim of this work was to study the central corneal thickness values and interobserver variability using a noncontact specular microscope. Methods: 62 eyes from 31 healthy subjects were studied with the Topcon SP-2000P noncontact specular microscope (Topcon Corp., Tokyo, Japan). 16 (51.61%) were females, and 15 (48.38%) were males. The mean age of the sample was 31.83±5.68 years. The mean of three consecutive measurements of the central corneal thickness was recorded by two investigators. Results: Mean central corneal thickness was 497±53 ?m for physician I and 497±51 ?m for physician II (p=0.982). No significant differences were found between the left and right corneas (p=0.999), between females and males (p=0.756), between ? 29-years-olds and ? 30-years-olds (p=0.945) or between myopic and hyperopic eyes (p=0.994). Conclusion: Noncontact specular microscopy is a recently introduced anatomical tool that can be used to study the human cornea in vivo (AU)

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¿Qué efecto ejercen las gotas anestésicas sobre la anatomía corneal? / What is the effect of anaesthetic drops on the corneal anatomy?

Introducción: Pese a que es conocido que ciertos anestésicos tópicos son tóxicos para el epitelio corneal y que las alteraciones en el espesor corneal pueden ser un indicador sensible de daño o lesión corneal, son pocos los estudios que se han encargado de analizar el posible efecto sobre el espesor corneal de la aplicación de gotas anestésicas. Por este motivo, el objetivo del estudio era analizar el espesor corneal antes y después de aplicar sobre la superficie corneal dos gotas de Colircusí® anestésico doble (tetracaína 0,1 por ciento y oxibuprocaína 0,4 por ciento. Alcon Cusí S.A. Barcelona). Material y métodos: Se realizó un estudio prospectivo en el que se analizó el espesor corneal en el centro de la córnea y en seis localizaciones paracentrales del ojo izquierdo de 31 sujetos voluntarios (edad media = 25,32ñ3,18).Se obtuvo con el Orbscan Topography System II (Orbscan, Inc., Salt Lake City, UT) la media de cinco mediciones consecutivas del espesor corneal tanto a nivel central como en seis localizaciones paracentrales: nasal, superonasal, inferonasal, temporal, superotemporal e inferotemporal. Las mediciones las realizó un investigador antes de utilizar el anestésico tópico y tres minutos después de aplicar dos gotas de Colircusí® anestésico doble (tetracaína 0,1 por ciento y oxibuprocaína 0,4 por ciento. Alcon Cusí S.A. Barcelona). Se analizaron las diferencias entre los valores del espesor corneal de cada localización obtenidos en la primera y la segunda exploración mediante una t de Student. Se consideraron estadísticamente significativos p valores menores de 0,05. Resultados: No se observaron diferencias significativas entre los valores previos y posteriores al empleo del anestésico en ninguna zona corneal. Sin embargo, en todas las localizaciones corneales estudiadas se encontraron aumentos y descensos del espesor corneal tras la anestesia. El mayor porcentaje de ascensos y descensos del espesor corneal se produjeron en la zona superonasal (61,29 por ciento) y superotemporal (45,16 por ciento) respectivamente. En un paciente el incremento del espesor corneal alcanzó las 115 mm en la zona nasal mientras que el mayor descenso (37 mm) se observó en la zona superotemporal de otro paciente. Conclusiones: Los valores medios del espesor corneal no varían significativamente tres minutos tras la instilación del anestésico local. Sin embargo, la anestesia mediante gotas puede afectar anatómicamente a la cornea provocando marcados ascensos y descensos en el espesor corneal de ciertos individuos (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)

Assessment of central corneal thickness in extreme myopic eyes

Purpose: To study the central corneal thickness values in two groups of extreme myopic patients (cycloplegic spherical equivalent refraction >=-12 diopters) and in a control group. Methods: We carried out ultrasonic pachymetry with the DGH 2000 AP ultrasonic pachymeter (DGH Technology, Inc., San Diego, CA, USA). Group I (n=45) was made up of patients with spherical equivalent refraction ranging from -12.00 to -18.00 diopters; group II (n=25) with spherical equivalent refraction > -18.00 diopters, and the control group (n = 34) was made up of patients with spherical equivalent refraction ranging from -0.25 to -3.00 diopters. Results: Mean central corneal thickness (mean±SD) was 531±42 ?m, 551±52 ?m and 538±35 ?m in groups I, II and controls, respectively (p=0.193). No significant differences between women and men were found in group I (p=0.314), group II (p=0.071) and the control group (p=0.113). No significant differences among age subgroups were found in group I (p=0.989), group II (p=0.641) or in the control group (p=0.397). Conclusions: In extreme myopic eyes there is a slight tendency for central corneal thickness to increase in the presence of higher degrees of myopia. Nevertheless, central corneal thickness in extreme myopic patients is similar to that noted in non-extreme myopic patients (AU)

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Assessment of differences in ocular morphometric measurements by using optical and applanation ultrasound biometry in the same eye / Conocimiento de las diferencias en las mediciones morfométricas oculares al emplear biometría óptica y ultrasónica de aplanación en el mismo ojo

Purpose of this work was to determine the differences in ocular axial length measurements carried out by one investigator using optical and ultrasound biometry on the same eye. In a prospective study, we measured the ocular axial length in 30 eyes of 30 different patients with the non-contact optical IOLMaster™ (Zeiss Humphrey System, CA, USA) and immediately afterwards with the ultrasonic Compuscan A-B (Storz, St. Louis, MO, USA). One investigator took three consecutive readings of the ocular axial length with both biometers; the means of these three consecutive readings were the ocular axial length values used in the study. The mean age of the sample was 33.55±8.32 years (range, 21 to 54 years). 23.33% (7 eyes) of the biometric procedures were conducted in women and 76.66% (23 eyes) in men. A t-Test for paired data was used to confirm the differences between the two measurement tools. P<0.05 was considered to be statistically significant. All measurements made with the IOLMaster™ unit were higher than those obtained with the Compuscan unit. The IOLMaster™ unit measurements were on average 0.38±0.20 mm higher than the Compuscan measurements (p<0.001). The mean ocular axial length was 23.82±2.18 mm as measured with the IOLMaster™ and 23.43±2.14 mm with the Compuscan A-B. The minimum difference between optical and ultrasound biometry was 0.12 mm and maximum was 0.74 mm. Optical and ultrasound biometry are two efficient anatomical tools for study of ocular anatomy. However, all anatomists should take into account the differences between the optical and ultrasound results when carrying out anatomical ocular studies in vivo (AU)

El propósito de este trabajo fue determinar las diferencias en las mediciones de la longitud axial realizadas por un investigador empleando biometría óptica y ultrasónica en el mismo ojo.En un estudio prospectivo se midió la longitud axial en 30 ojos de 30 pacientes diferentes con el IOLMaster? óptico de no contacto (Humphrey System, CA, USA) e inmediatamente después con el Compuscan A-B ultrasónico (Storz, St. Louis, MO, USA). Un investigador realizó tres mediciones consecutivas de la longitud axial ocular con ambos biómetros; la media de estas tres mediciones consecutivas de la longitud axial ocular fueron los valores empleados en el estudio.La edad media de la muestra era de 33.55?8.32 años (rango, 21 a 54 años). El 23.33 per cent (7 ojos) de los procedimientos biométricos fueron realizados en mujeres y el 76.66 per cent (23 ojos) en varones. Se empleó el t-Test para confirmar las diferencias entre las dos herramientas de medición. P valores inferiores a 0.05 fueron considerados estadísticamente significativos.Todas las mediciones realizadas con la unidad IOLMaster? fueron mayores que las realizadas con la unidad Compuscan A-B. Las mediciones con la unidad IOLMaster? fueron una media de 0.38?0.20 mm superiores que las mediciones realizadas con la unidad Compuscan (p<0.001). La longitud axial ocular media obtenida con el IOLMaster? fue de 23.82?2.18 mm y la medida con el Compuscan A-B fue de 23.43?2.14. La diferencia mínima entre la biometría óptica y la ultrasónica fue de 0.12 mm y la máxima fue de 0.74 mm.La biometría óptica y la biometría ultrasónica son dos eficientes herramientas anatómicas para estudiar la anatomía ocular. Sin embargo, los anatómicos deben tener en cuenta las diferencias entre la biometría ultrasónica y la óptica cuando se realicen estudios anatómicos oculares in vivo (AU)

Repeatbility of central corneal thickness and ocular anterior chamber depth measurements with the orbscan topography system / Repetibilidad de las mediciones del espesor corneal central y la profundidad de la cámara ocular anterior con el sistema topográfico orbscan

The Orbscan topography system is a new anatomical noncontact system that allows study of central corneal thickness and ocular anterior chamber depth. It is currently important to know if there are significant differences among different observers when morphometric studies are carried out with the Orbscan System. Following on from this, the present work focuses on the repeatability of the new Orbscan Topography System II measurements. At the Rahhal Ophthalmology Clinic and the Faculty of Medicine of Valencia (Spain), we carried out a prospective study involving 46 eyes of 46 healthy patients: 27 were women (58.59%) and 19 were men (41.30%). The mean age of the sample was 29.93 ± 6.6 years (range: 18-47 years). One physician carried out central corneal thickness and ocular anterior chamber depth measurements with the Orbscan Topography System II (Bausch & Lomb Surg, Barcelona, Spain), while a second physician measured the corneal thickness and ocular anterior chamber depth again. The means of two consecutive measurements were used. Only one eye per patient was considered for the statistical analysis. The repeatability of the Orbscan measurements was analysed by comparing the results obtained by physicians 1 and 2. The mean central corneal thickness of the sample (mean ±SD) was 549.39 ±46.65 ?m (physician 1) and 549.32 ±47 ?m (physician 2). Thus, no significant differences were found between physicians (p=0.994). The mean ocular anterior chamber depth (mean ±SD) was 3.14 ±0.27 mm (physician 1) and 3.14 ±0.26 mm (physician 2). No significant differences were found between the physicians (p=0.978). Women had significantly greater corneal thickness values than men (p=0.003 for physician 1, and p=0.004 for physician 2). No significant differences between the sexes were found for ocular anterior chamber depth. In sum, the Orbscan Topography System II offers a high degree of repeatability for central corneal thickness and ocular anterior chamber depth measurements. This situation should facilitate the study of corneal and ocular anatomy in vivo (AU)

El sistema topográfico Orbscan es un nuevo sistema anatómico de no contacto que permite estudiar el espesor corneal central y la profundidad de la cámara ocular anterior. Actualmente es importante conocer si hay diferencias significativas entre diferentes observadores cuando los estudios morfométricos oculares son realizados con el sistema Orbscan. Por este motivo, el presente trabajo incide en la repetibilidad de las mediciones realizadas con el nuevo Orbscan Topography System II.En la Clínica Oftalmológica Rahhal y la Facultad de Medicina de Valencia (España), hemos realizado un estudio prospectivo en 46 ojos de 46 pacientes sanos: 27 eran mujeres (58.59 por ciento) y 19 eran varones (41.30 por ciento). La edad media de la muestra era de 29.93ñ6.6 años (rango: 18-47 años). Un observador realizó las mediciones del espesor corneal central y la profundidad de la cámara anterior ocular con el Orbscan Topography System II (Bausch & Lomb Surg, Barcelona, Spain), mientras que un segundo observador midió de nuevo el espesor corneal central y la profundidad de la cámara ocular anterior. La media de dos mediciones consecutivas fue empleada. Sólo un ojo por paciente fue utilizado para el análisis estadístico. La repetibilidad de las mediciones Orbscan fue analizada comparando los resultados obtenidos por el observador 1 y 2.La media del espesor corneal central de la muestra (mediañSD) fue 549.39ñ46.65 mm (observador 1) y 549.32ñ47 mm (observador 2). No se encontraron diferencias significativas entre los observadores (p=0.994). La media de la profundidad de la cámara ocular anterior (mediañSD) fue de 3.14ñ0.27 mm (observador 1) y 3.14ñ0.26 mm (observador 2). De este modo, no se encontraron diferencias significativas entre los observadores (p=0.978). Las mujeres tuvieron unos valores del espesor corneal central significativamente superiores que los de los varones (p=0.003 para el observador 1, y p=0.004 para el observador 2). No fueron encontradas diferencias significativas entre sexos en la profundidad de la cámara anterior ocular.En resumen, el Orbscan Topography System II ofrece un alto grado de repetibilidad para las mediciones del espesor corneal central y la profundidad de la cámara ocular anterior. Esta situación debe facilitar el estudio de la anatomía corneal y ocular en vivo (AU)

Morphometric study of the ocular anterior chamber depth with the non-contact optical IOLMaster / Estudio morfométrico de la profundidad de la cámara anterior del ojo con el IOLMaster de no contacto

Laser interferometric biometry is a modern technique that allows us to study the eye without having to touch the ocular surface. With non-contact optical biometry, it is possible to determine the ocular anterior chamber depth values in vivo. Following on from this, we analysed ocular anterior chamber depths in a sample of healthy subjects at the Rahhal Ophthalmology Clinic and the Department of Morphological Science of the Faculty of Medicine, Valencia, Spain. To this end, we measured the ocular anterior chamber depth with the non-contact IOLMaster™ (Zeiss Humphrey System, CA, USA) in 100 patients (n=100; mean age 29.15±8.18 years; 50.0% women and 50.0% men). We established three groups of patients according to cycloplegic spherical equivalent refraction: group A consisted of eyes of below -10.00 diopters; group B comprised eyes ranging between - 10.25 and - 16.00 diopters; and group C included eyes with a value equal to or higher than -16.25 diopters. Mean ocular anterior chamber depth values were 3.52±0.28 mm, 3.59±0.38 mm and 3.78±0.24 mm in groups A, B and C respectively. Differences in mean ocular anterior chamber depth among groups were significant (p=0.004). Differences in mean values between women and men were not significant in group A (p=0.613), group B (p=0.631) or Group C (p=0.065). In sum, partial coherence interferometry is an efficient anatomical tool for study of the ocular anterior chamber depth of healthy subjects. However, further research is necessary in order to detect its validity when carrying out morphometric studies on pathological eyes (AU)

La biometría mediante interferometría láser es una técnica moderna que permite estudiar el globo ocular sin necesidad de tener que contactar con la superficie ocular. Con la biometría óptica de no contacto es posible determinar en vivo los valores de la profundidad de la cámara ocular anterior. Por este motivo hemos analizado en la Clínica Oftalmológica Rahhal y en el Departamento de Ciencias Morfológicas de la Facultad de Medicina de Valencia (España), la profundidad de la cámara ocular anterior en una muestra de sujetos sanos. Para este menester hemos medido la profundidad de la cámara anterior ocular con el IOLMasterÔ de no contacto (Zeiss Humphrey System, CA, USA) en 100 pacientes (n=100; edad media 29.15ñ8.18 años; 50.0 por ciento mujeres y 50.0 por ciento varones). Formamos tres grupos de pacientes de acuerdo con su equivalente esférico cicloplégico: el grupo A estaba formado por ojos con menos de -10.00 dioptrías; el grupo B formado por ojos que oscilaban entre -10.25 y -16.00 dioptrías; y el grupo C incluyó ojos con un valor del equivalente esférico igual o superior a -16.25 dioptrías. Los valores medios de la profundidad de la cámara ocular anterior fueron 3.52ñ0.28 mm, 3.59ñ0.38 mm y 3.78ñ0.24 mm en los grupos A, B y C, respectivamente. Las diferencias en los valores medios de la profundidad de la cámara ocular anterior fueron significativas (p=0.004). Las diferencias en los valores medios entre mujeres y varones no fueron significativas en los grupos A (p=0.613), B (p=0.631) y C (p=0.065).En resumen, la interferometría de coherencia parcial es una herramienta eficaz para estudiar la profundidad de la cámara anterior ocular en los sujetos sanos. Sin embargo, son necesarias nuevas investigaciones para detectar su validez al realizar estudios morfométricos en ojos patológicos (AU)

Consolidating the anatomical relationship between ocular axial length and spherical equivalent refraction / Consolidando la relación anatómica entre la longitud axial ocular y el equivalente esférico refractivo

The basis of refractive error is ocular axial length since this will indicate the presence of either a myopic eye or a hyperopic one, Today, ultrasonic biometry can be used to study the anatomical differences between the ocular myopic and the hyperopic globe. Following on from this, we analysed the anatomical relationship between ocular axial length, refraction and the degree of refractive error. To this end, we measured the ocular axial length with the Compuscan A-B Storz ultrasonic biometer (San Louis, MO, USA) in 100 patients with myopia (n=100; mean age 33.53±8.15; 51.0% women and 49.0% men) and 100 with hyperopia (n=100; mean age 30.90±7.73; 56.0% women and 44.0% men). We established three groups of myopic patients (group M1: -6.50 to -12.00 diopters; group M2: -12.50 to -18.00 diopters; group M3: -18.25 to -24.00 diopters) and two groups of hyperopic patients (group H1: +1.75 to +4.00 diopters; group H2: +4.50 to +9.50 diopters). Mean ocular axial length was 27.11±1.55 mm in M1, 28.70±1.55 in M2, 29.78±1.10 in M3, 21.66±0.83 in H1 and 21.31±0.92 in H2 (p < 0.001). Among the myopic groups (p < 0.001) and between the hyperopic groups (p=0.025), differences in mean ocular axial length were significant. Women had an ocular axial length, which was significantly less in the hyperopic groups and in M1 (p=0.020 in H1, p=0.046 in H2 and p=0.027 in M1). In M2 and M3, no significant differences were found (p=0.742 and p=0.104, respectively). Our study confirms the involvement of ocular axial length in the refractive state and reveals a major difference in the way mean ocular axial length behaves between the sexes as a function of the degree of myopic error presented (AU)

La base de los errores refractivos es la longitud axial ocular puesto que nos indicará la presencia de un ojo miope o un ojo hipermétrope. Hoy, la biometría ultrasónica puede usarse para estudiar las diferencias anatómicas entre el globo ocular miope y el hipermétrope. Por este motivo, hemos analizado la relación anatómica entre la longitud axial ocular, la refracción y el grado de defecto refractivo. Para este fin hemos medido la longitud axial ocular con el biómetro ultrasónico Compuscan A-B Storz (San Louis, MO, USA) en 100 pacientes con miopía (n=100; edad media 33.53?8.15; 51.0 por ciento mujeres y 49.0 por ciento hombres) y 100 con hipermetropía (n=100; edad media 30.90?7.73; 56.0 por ciento mujeres y 44.0 por ciento hombres). Establecimos tres grupos de pacientes miopes (grupo M1: -6.50 a -12.00 dioptrías; grupo M2: -12.50 a -18.00 dioptrías; grupo M3: -18.25 a -24.00 dioptrías) y dos grupos de pacientes hipermétropes (grupo H1: +1.75 a +4.00 dioptrías; grupo H2: + 4.50 a +9.50 dioptrías).La longitud axial ocular era 27.11?1.55 mm en M1, 28.70?1.55 en M2, 29.78?1.10 en M3, 21.66?0.83 en H1 y 21.31?0.92 en H2 (p<0.001). Entre los grupos miópicos (p<0.001) y entre los grupos hipermétropes (p=0.025), las diferencias en la longitud axial ocular fueron significativas. La mujeres tuvieron una longitud axial ocular que fue significativamente inferior en los grupos hipermétropes y en el grupo M1 (p=0.020 en H1, p=0.046 en H2 y p=0.027 en M1). En M2 y M3 no se encontraron diferencias significativas (p=0.742 y p=0.104 respectivamente).Nuestro estudio confirma la implicación de la longitud axial ocular en el estado refractivo y revela una diferencia importante en el modo en que la longitud axial ocular es diferente entre los sexos en función del grado de error miópico presentado (AU)

Morphometric study of the hyperopic central cornea / Estudio morfométrico de la córnea central hipermétrope

Refractive surgery by means of excimer laser results in thinner postoperative corneas following corneal photoablation. This implies the need to previously measure the central corneal thickness in order to avoid the risk of keratectasia. In recent years and after the introduction of excimer laser refractive surgery, several studies have focused on corneal morphometry in myopic eyes. However, we have not found any references to hyperopic eyes. Following on from this, we have studied central corneal thickness in 100 healthy hyperopic eyes by using ultrasonic pachymetry. Patients were subdivided by refractive errors into group 1 (manifesting spherical equivalent refraction ? +4.00 diopters) and group 2 (manifesting spherical equivalent refraction > +4.00 diopters). In group 1, central corneal thickness was 555.20±33.31 ?m (mean ± standard deviation) and in group 2 it was 548.95±31.87. No significant differences were found between group 1 and group 2 (p= 0.346). In group 1 there were significant differences in mean central corneal thickness between females and males (p= 0.012) but not in group 2 (p= 0.947). No significant differences in the mean values of central corneal thickness as a function of age for the members of group 1 and group 2 were noted (p= 0.198 and p= 0.628, respectively). Central corneal anatomy in healthy hyperopic eyes is similar to that seen in myopic eyes (AU)

La cirugía refractiva con láser excimer da como resultado córneas postoperatorias adelgazadas tras la fotoablación corneal. Esto implica la necesidad de medir previamente el espesor corneal central para evitar el riesgo de queratectasias. En años recientes y tras la introducción de la cirugía refractiva con láser excimer, diversos estudios se han centrado en la morfometría corneal de los ojos miopes.Sin embargo, no hemos encontrado referencias a los ojos hipermétropes. Debido a esto, hemos estudiado el espesor corneal central en 100 ojos hipermétropes sanos empleando la paquimetría ultrasónica. Los pacientes fueron subdivididos según el error refractivo dentro del grupo 1 (equivalente esférico refractivo manifiesto ? + 4.00 dioptrías) y grupo 2 (equivalente esférico refractivo manifiesto > + 4.00 dioptrías).En el grupo 1, el espesor corneal central fue de 555.20?33.31 µm (media ? desviación estándar) y en el grupo 2 fue 548.95?31.87. No se encontraron diferencias significativas entre el grupo 1 y el grupo 2 (p=0.346). En el grupo 1 se encontraron diferencias significativas en el espesor corneal central entre las mujeres y los varones (p=0.012) pero no en el grupo 2 (p=0.947).No se encontraron diferencias significativas en los valores medios del espesor corneal central en función de la edad para los miembros del grupo 1 y del grupo 2 (p=0.198 y p=0.628, respectivamente).La anatomía corneal central en los ojos hipermétropes sanos es similar a la observada en los ojos miopes (AU)