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Chamber Depth (chamber + depth)
Kinds of Chamber Depth Selected AbstractsRefractive error and ocular biometry in Jordanian adultsOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 4 2005Edward A. H. Mallen Abstract The aim of this study was to establish the prevalence of refractive errors in Jordanian adults of working age, and to study the ocular biometric correlates of refractive error in this population. Refractive error and ocular biometry were measured in 1093 Jordanian adult subjects aged 17,40 years to determine the prevalence of refractive error, and explore structural correlations of ametropia. Refractive error was measured using a Grand-Seiko GR-3100K closed-view infrared autorefractor. Ocular component measurements were made using A-scan ultrasonography and autokeratometry. The prevalence of myopia [spherical equivalent refraction (SER) less than ,0.50 DS] and hyperopia (SER greater than +0.50 DS) was 53.71 and 5.67% respectively; 40.62% of the sample was emmetropic (refraction between +0.50 D and ,0.50 D inclusive in both principal meridians). The distribution of SER was found to show marked leptokurtosis, exhibiting a peak between plano and 1 D of myopia. Corneal radius, anterior chamber depth, crystalline lens thickness, vitreous chamber depth and axial length (AL) parameters were normally distributed in the population studied. AL to corneal curvature ratio was not normally distributed, and showed marked leptokurtosis. Linear regression analysis showed that AL correlated most closely with spherical equivalent refractive error. This study has established a database of refractive error prevalence and ocular biometric correlates of ametropia in a Middle Eastern population of working age. [source] Cling film as a barrier against CJD in corneal contact A-scan ultrasonographyOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2003Asha Rani Abstract Purpose: To determine the validity of covering a corneal contact transducer probe with cling film as protection against the transmission of Creutzfeldt,Jakob disease (CJD). Methods: The anterior chamber depth, lens thickness and vitreous chamber depth of the right eyes of 10 subjects was recorded, under cycloplegia, with and without cling film covering over the transducer probe of a Storz Omega Compu-scan Biometric Ruler. Measurements were repeated on two occasions. Results: Cling film covering did not influence bias or repeatability. Although the 95% limits of agreement between measurements made with and without cling film covering tended to exceed the intrasessional repeatability, they did not exceed the intersessional repeatability of measurements taken without cling film. Conclusions: The results support the use of cling film as a disposable covering for corneal contact A-scan ultrasonography to avoid the risk of spreading CJD from one subject to another. [source] Relative Axial Myopia Induced by Prolonged Light Exposure in C57BL/6 MicePHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2010Xiangtian Zhou Ambient lighting is essential for ocular development in many species, however, disruption in diurnal lighting cycle can affect the development in refraction and axial growth of the eye. This study investigated the effects of prolonged daily lighting on refraction and various optical components of the eye by raising C57BL/6 mice under three different light/dark cycles (18/6, 12/12 and 6/18). Egr-1 mRNA expression, apoptosis and histology of the retina and size of the scleral fibrils were evaluated in these three lighting cycles. Results showed that there was a trend of myopic development, increasing vitreous chamber depth and thinning of the retina in eyes from 6/18 to 18/6 groups. Retinal Egr-1 mRNA expression and diameter of scleral fibrils were reduced with the prolongation of daily lighting from 6/18 to 18/6. However, retinal apoptosis was not detected in all the groups. These results suggest that prolonged lighting can induce axial myopia in inbred mice. This model, which uses mice with similar genetic backgrounds, provides an alternative to the currently available models and therefore is useful for evaluation of refractive errors caused by changes in environmental illumination. [source] Implantable Imaging System for Visual ProsthesisARTIFICIAL ORGANS, Issue 6 2010Chuanqing Zhou Abstract In order to propose a method of intraocular imaging system for the visual prosthesis, an implantable microcamera was developed and evaluated in vivo. The microcamera was specially developed and shaped to fit the rabbit's lens capsule and encapsulated with the biocompatible silicone. To evaluate the feasibility of this novel approach, the custom-built device was implanted following the surgical extraction of rabbit's lens. And clinical examinations were performed 1 day, 3 days, 1 week, 2 week, and 1 month postoperatively, including slit-lamp examination, intraocular pressure, wound status, anterior chamber depth, the presence of the iris fibrosi of neovascularization, and the position of the implant. Real-time imaging was performed in vivo 1 month after the operation, and the acquired images were processed with the software and hardware that were specially developed for generating the stimulating pulses. Short-term results showed the novel approach is promising. [source] Effect of age on anterior chamber angle configuration in Asians determined by anterior segment optical coherence tomography; clinic-based studyACTA OPHTHALMOLOGICA, Issue 6 2010Mi Hyun Cheon Acta Ophthalmol. 2010: 88: e205,e210 Abstract. Purpose:, To evaluate the distribution of anterior chamber angle (ACA) parameters and to assess association of these parameters with age in Asian subjects. Methods:, Four hundred and thirty-nine consecutive Korean subjects aged from 30 to 89 were enrolled from a university clinic. All participants were scanned using anterior segment optical coherence tomography (AS-OCT, Visante, version 2.0). We measured ACA parameters such as anterior chamber depth (ACD), angle opening distance at 500 and 750 ,m (AOD500,750), angle recess area at 500 and 750 ,m (ARA500,750), trabecular iris space area at 500 and 750 ,m (TISA500,750), and determined age-related changes in these parameters with use of a linear mixed effect model that adjusted for gender, axial length, intraocular pressure, and keratometry data. Slopes of ACA parameters as a function of age were determined. For various AS-OCT parameters, the normalized slope was calculated by dividing the slope by the mean value. Results:, All analysed ACA parameters decreased with age in both nasal and temporal quadrants. Axial length and keratometry data were significant covariates for ACA changes. The slopes of ACD were ,0.02396 mm/year, AOD500, ARA500, and TISA500 measured at the temporal angle were ,0.00634 mm/year, ,0.0019 mm2/year, and ,0.00177 mm2/year, respectively. There was no age-dependent difference in central corneal thickness (p value; 0.4597) Based on the normalized slopes, the AOD showed the steepest slope at both temporal and nasal sectors. Conclusion:, All ACA parameters assessed by AS-OCT, which accounted for other ocular biometric parameters, showed significant negative slopes with increasing age. These results should be considered when assessing changes in the anterior chamber over time. [source] 4333: How does scleral buckling affect the anterior segment of the eye?ACTA OPHTHALMOLOGICA, Issue 2010FJ ASCASO Purpose To describe the modifications produced in the anterior segment of the eye after placing an encircling scleral buckling (SB) in terms of corneal morphology, biomechanics and intraocular pressure. Methods A prospective study of 15 eyes with rhegmatogenous retinal detachment who underwent pars plana vitrectomy combined with a scleral buckle (PPV/SB), and 12 eyes with vitreous hemorrhage treated with PPV alone. We measured preoperatively and 1-month after surgery the corneal biomechanical properties using the Ocular Response Analyzer (ORA), including corneal hysteresis (CH), corneal resistance factor (CRF), intraocular pressure (IOPg), and corneal compensated IOP (IOPcc). Moreover, we defined the corneal morphology by 4 parameters provided by the topographer Orbscan IIz: mean corneal power (dioptres), standard deviation, thinnest point (µm), and anterior chamber depth (ACD) (mm). Results Mean CH values were significantly diminished following PPV/SB (p=0.003). We found no significant changes in CRF. IOPg and IOPcc mean values were significantly increased only in the PPV/SB group (p=0.019 and p=0.010, respectively) but not in PPV group (p=0.715 and p=0.273, respectively). In PPV/SB group, IOPcc mean values were significantly higher than IOPg before (p=0.001) and after surgery (p=0.003), but not in the other group. None of the morphological parameters were modified after surgery in any of the two study groups (p>0.05) Conclusion Anterior segment morphology was not modified after placing a SB. Corneal biomechanical properties showed a reduction in CH, probably due to a vascular constriction and reduction of the eye compliance. PPV might be considered a less invasive approach for the repair of noncomplex retinal detachments than PPV/SB. [source] Evaluation of anterior segment parameter changes using the Pentacam after uneventful phacoemulsificationACTA OPHTHALMOLOGICA, Issue 5 2010Selim Doganay Abstract. Purpose:, This study set out to evaluate the influences of uneventful phacoemulsification on the anterior segment parameters obtained with the Pentacam rotating Scheimpflug camera and intraocular pressure (IOP). Methods:, A total of 42 eyes of 34 patients (26 men, eight women) were evaluated preoperatively, and at 1, 3 and 6 months postoperatively with the Pentacam. Intraocular pressure was measured with the Goldmann applanation tonometer. The non-parametric paired t -test was used to compare preoperative and 1-, 3- and 6-month postoperative measurements of anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA) width, central corneal thickness (CCT), the central 3-, 5- and 7-mm corneal volume (CV), pupil size, and IOP. Pearson's correlation test was used to evaluate the relationships between IOP and ACD, ACV and ACA width. Results:, The differences between ACD, ACV, ACA and IOP values taken preoperatively and those taken postoperatively at 1, 3 and 6 months were statistically significant (p < 0.05). The differences between CCT, central 3-, 5- and 7-mm CV, and pupil size measurements taken preoperatively and those taken postoperatively at 1, 3 and 6 months were not statistically significant (p > 0.05). The decrease in IOP was not correlated with the changes in ACD, ACV and ACA (p > 0.05). Conclusions:, Uneventful phacoemulsification significantly reduced IOP, increased ACD and ACV, and widened the ACA. However, alterations in CV, CCT and pupil size values were not statistically significant. Alterations in ACD, ACV, ACA and IOP remain stable after the first month of surgery. [source] From epidemiology to lysyl oxidase like one (LOXL1) polymorphisms discovery: phenotyping and genotyping exfoliation syndrome and exfoliation glaucoma in IcelandACTA OPHTHALMOLOGICA, Issue 5 2009Fridbert Jonasson Abstract. The first Icelandic articles on exfoliation syndrome (XFS) and exfoliation glaucoma (XFG) appeared some 35 years ago in 1974. Articles since then have included epidemiology, pedigree-based and twin-studies as well as investigations into XFG response to medical therapy and XFS/XFG genetics. All studies found XFS/XFG to be common in Iceland and to be age-related. The Reykjavik Eye Study (RES), a population-based epidemiological study, was first conducted in 1996. The RES found that XFS and XFG prevalence in patients aged 50 years and older was 11% and that XFS/XFG was more common in women than in men. These results were confirmed in 5- and 12-year incidence studies that also suggested that detailed characterization of the phenotype is important, including pupil dilation. In the RES, eyes with XFS were found to be clinically unilateral in about half of cases and to have higher mean intraocular pressure (IOP) than non-XFS eyes. However, XFS was not found to be associated with central corneal thickness, corneal curvature, anterior chamber depth, lens thickness, lens opacification or optic disc morphology. About 15% of persons with XFS had XFG, and XFG eyes had higher risk of developing visual impairment and blindness than eyes with primary open-angle glaucoma. The first genetic studies on Icelanders, conducted about 12 years ago, were linkage studies and were unsuccessful in discovering the genetics behind XFS/XFG. However, in 2007 a genome-wide association study in Iceland using more than 300 000 markers [single nucleotide polymorphisms (SNPs)] on a relatively small number of patients did discover that lysyl oxidase like 1 (LOXL1) on chromosome 15q24 is a major gene for XFS/XFG. These results have now largely been replicated world-wide. [source] Anterior chamber parameters measured by the Pentacam CES after uneventful phacoemulsification in normotensive eyesACTA OPHTHALMOLOGICA, Issue 5 2009Özlenen Ö. Uçakhan Abstract. Purpose:, We set out to quantify changes in the anterior chamber volume (ACV), anterior chamber depth (ACD) and anterior chamber angle (ACA) measurements obtained by the Pentacam rotating Scheimpflug camera following uneventful phacoemulsification surgery in normotensive eyes with open iridocorneal angles. Methods:, We enrolled 44 eyes of 44 consecutive patients undergoing cataract extraction in this prospective study. Patients with a history of glaucoma, angle-closure glaucoma or any other concurrent ocular disease were excluded. A detailed eye examination including intraocular pressure (IOP) measurement was performed and ACV, ACD and inferior, superior, temporal and nasal ACA measurements were obtained in each patient eye using the Pentacam Comprehensive Eye Scanner (Pentacam CES) before and 3 months after phacoemulsification and intraocular lens (IOL) implantation with temporal clear corneal incision. Data were compared using paired t -test and one-way anova. Results:, Mean preoperative ACV, ACD, ACA and IOP measurements were 164.7 ± 49.8 mm3, 3.0 ± 0.8 mm, 35.7 ± 10.2 ° and 15.8 ± 3.7 mmHg, respectively. Three months postoperatively, mean ACV, ACD, ACA and IOP measurements were 200.9 ± 33.3 mm3, 3.9 ± 0.9 mm, 41.5 ± 6.5 ° and 13.2 ± 3.9 mmHg, respectively. Postoperative mean ACV, ACD and ACA values in all four quadrants were significantly increased (p < 0.0001, p < 0.0001, p < 0.0001, respectively), whereas IOP was significantly reduced (p < 0.0001). Conclusions:, The Pentacam CES allowed very easy, fast, automatic and non-contact quantification of the anterior chamber parameters pre- and postoperatively in all patient eyes. Measurements obtained confirm that in normotensive eyes with open iridocorneal angles, the ACV and ACD increase and the ACA widens in all quadrants 3 months after uneventful phacoemulsification and IOL implantation. These changes are accompanied by a significant fall in IOP in the short term. [source] Comparison of anterior chamber depth measurements taken with the Pentacam, Orbscan IIz and IOLMaster in myopic and emmetropic eyesACTA OPHTHALMOLOGICA, Issue 4 2009Canan Asli Utine Abstract. Purpose:, This study determined to assess the degree of agreement between anterior chamber depth (ACD) measurements obtained using three different devices and to analyse the relationship between ACD and spherical equivalent (SE) refraction. Methods:, In this cross-sectional study, 42 eyes of 42 patients with a mean SE of , 4.69 ± 4.61 D (range 0.00 D to , 14.88 D) were analysed. Measurements of ACD between the corneal epithelium and the anterior surface of the crystalline lens, obtained using the Pentacam, Orbscan IIz and IOLMaster, were compared. The relationships between SE and ACD measurements obtained with different devices were also investigated. The results were analysed using Bland,Altman analyses, single-sample t -test and Pearson's correlation test. Results:, Orbscan ACD measurements were an average of 0.05 mm less than Pentacam measurements (p = 0.01). IOLMaster measurements were an average of 0.06 mm less than Orbscan measurements (p < 0.001). None of the ACD values measured by any of the devices were correlated with increasing SE (p > 0.05 for all). There was a weak positive correlation between SE and the difference in ACD measurements with Pentacam and Orbscan (p = 0.04); however, the differences between Pentacam and IOLMaster ACD measurements and Orbscan and IOLMaster ACD measurements seemed to be independent of SE (p = 0.17 and p = 0.54, respectively). Conclusions:, The ACD in clinically normal eyes is measured differently by various non-ultrasonic devices. However, the observed mean error between these modalities is too small to create any noticeable difference in refractive outcome. No significant relationship was found between SE and ACD measurements obtained by Pentacam, Orbscan or IOLMaster. [source] Relationships between ocular dimensions and adult stature among participants in the Reykjavik Eye StudyACTA OPHTHALMOLOGICA, Issue 6 2005Thor Eysteinsson Abstract. Purpose:,To examine the relationships between adult stature, age and ocular dimensions in a large homogenous, white population. Methods:,We used the national population census for Reykjavik to select a random sample of adults aged 50 years or older. A total of 846 persons were examined. Scheimpflug images were used to measure anterior chamber depth. Ultrasound was used to measure axial length, lens thickness and vitreous chamber depth. An autorefracto-keratometer was used to measure autorefractive and keratometric values, including the radius of the corneal curvature. Stereo fundus photographs were taken of the optic disc and measurements of the disc diameters were made using computer software. Results:,Height correlated positively with axial length in the multivariate model (B = 0.020, 95% CI 0.006,0.034, p < 0.01). Both age and height showed significant correlations with vitreous chamber depth, where the correlation with age was negative (B = , 0.016, 95% CI , 0.006 to , 0.025, p < 0.005) and the correlation with height was positive (B = 0.019, 95% CI 0.005,0.034, p < 0.01). Height also showed a positive correlation with the radius of the corneal curvature (B = 0.008, 95% CI 0.004,0.011, p < 0.001). Anterior chamber depth had a negative correlation with age (B = , 0.013, 95% CI , 0.010 to , 0.016, p < 0.001), whereas lens thickness had a significant positive correlation with age (B = 0.019, 95% CI 0.016,0.023, p < 0.001). We found a significant negative correlation between axial length and refraction/spherical equivalent (r = , 0.595, p < 0.0001). Discussion:,Our results indicate that there is a significant relationship between height and several ocular dimensions in this adult population and confirms a negative correlation between axial length and refraction. [source] Association between stature, ocular biometry and refraction in an adult population in rural Myanmar: the Meiktila eye studyCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 9 2007Hui Min Wu MD PhD Abstract Purpose:, To study the association between adult stature and ocular biometric parameters and refraction. Methods:, In a population-based cross-sectional ophthalmic survey of 2418 adults (,40 years old) living in the rural villages in central Myanmar, height and weight were measured using a standardized protocol, and body mass index was calculated. Non-cycloplegic refraction and corneal curvature were determined by an autorefractor. Ultrasound pachymetry was performed and ocular biometry, including axial length, anterior chamber depth, lens thickness and vitreous chamber length were measured using A-mode ocular ultrasonography. Results:, Height and weight were significantly correlated with age, gender and all the ocular biometric parameters, except lens thickness. After adjusting for age and gender, taller and heavier persons had eyes with longer axial length, deeper anterior and vitreous chambers, and flatter and thicker corneas than shorter persons. Height was not significantly correlated with refraction, and heavier persons tended to be less myopic (P < 0.001). Multivariate linear regression models revealed consistent results with the findings for association between height, weight and ocular biometry and refractive error. Conclusions:, Adult stature is independently associated with vitreous chamber length and corneal radius in this Burmese population. Heavier persons were slightly hyperopic. [source] | ||||||||||