Cup Depth Research Articles

Diagnostic accuracy of Heidelberg Retina Tomograph III classifications in a Turkish primary open-angle glaucoma population

This study aimed to evaluate the diagnostic accuracy of Moorfields regression analysis (MRA) and the glaucoma probability score (GPS) in primary open-angle glaucoma (POAG) and to measure the level of agreement between the two algorithms in classifying eyes as normal or abnormal in a Turkish population. We prospectively selected 184 healthy subjects and 158 subjects with POAG, who underwent an ophthalmological examination, visual field analysis and imaging with the Heidelberg Retina Tomograph II, using HRT III software, Version 3.0. The diagnostic accuracies of the two classifications were measured when the borderline was taken as either normal (highest specificity criteria) or abnormal (highest sensitivity criteria). The agreement between them was calculated using the unweighted kappa (kappa) coefficient. Optic nerve head topographic parameters showed statistically significant differences between the control and POAG groups (p < 0.001). The parameters with the highest area under the receiver operating characteristic curves were global GPS (0.86), cup : disc area (0.85), rim : disc area (0.85) and vertical cup : disc (0.85). According to the highest specificity criteria, MRA had a sensitivity of 67.7% and a specificity of 95.1%, whereas the GPS had a sensitivity of 70.9% and a specificity of 88.0%. According to the highest sensitivity criteria, MRA had a sensitivity of 81.0% and a specificity of 75.0%, whereas the GPS had a sensitivity of 89.2% and a specificity of 57.6%. A moderate agreement of 68% (233 eyes) with a kappa coefficient of 0.51 was found between MRA and the GPS. The GPS automated classification showed similar sensitivity to MRA, but considerably lower specificity, when applied in a Turkish population.

Tele-transmission of Stereoscopic Images of the Optic Nerve Head in Glaucoma via Internet

The objective was to describe an inexpensive system to visualize stereoscopic photographs of the optic nerve head on computer displays and to transmit such images via the Internet for collaborative research or remote clinical diagnosis in glaucoma. Stereoscopic images of glaucoma patients were digitized and stored in a file format (joint photographic stereoimage [jps]) containing all three-dimensional information for both eyes on an Internet Web site (www.trizax.com). The size of jps files was between 0.4 to 1.4 MB (corresponding to a diagonal stereo image size between 900 and 1400 pixels) suitable for Internet protocols. A conventional personal computer system equipped with wireless stereoscopic LCD shutter glasses and a CRT-monitor with high refresh rate (120 Hz) can be used to obtain flicker-free stereo visualization of true-color images with high resolution. Modern thin-film transistor-LCD displays in combination with inexpensive red-cyan goggles achieve stereoscopic visualization with the same resolution but reduced color quality and contrast. The primary aim of our study was met to transmit stereoscopic images via the Internet. Additionally, we found that with both stereoscopic visualization techniques, cup depth, neuroretinal rim shape, and slope of the inner wall of the optic nerve head, can be qualitatively better perceived and interpreted than with monoscopic images. This study demonstrates high-quality and low-cost Internet transmission of stereoscopic images of the optic nerve head from glaucoma patients. The technique allows exchange of stereoscopic images and can be applied to tele-diagnostic and glaucoma research.

Early Outcomes of Pyrolytic Carbon Hemiarthroplasty for the Treatment of Trapezial-Metacarpal Arthritis

Pyrolytic carbon implants have been successfully used in the treatment of osteoarthritis of the metacarpophalangeal and proximal interphalangeal joints. Recently, pyrolytic carbon hemiarthroplasties have been proposed for the treatment of osteoarthritis of the trapezial-metacarpal (TM) joint of the thumb. We wished to review our short-term outcomes for this device in the treatment of TM arthritis. Fifty-four arthritic TM joints in 49 patients, with a mean age of 59 years, were treated with use of a pyrolytic carbon hemiarthroplasty procedure. Underlying diagnoses included osteoarthritis in 44 thumbs, rheumatoid arthritis in 8 thumbs, psoriatic arthritis in 1 thumb, and juvenile rheumatoid arthritis in 1 thumb. The patients were followed up clinically as well as radiologically for an average of 22 months postoperatively. The overall 22-month survival rate excluding scaphotrapezio-trapezoidal joint arthritis was 80% according to a Kaplan-Meier analysis. Ten metacarpal subluxations were observed. Seven of these cases were salvaged by increasing the depth of the trapezial cup. A total of 15 reoperations were required in this cohort. No complications were seen in the patients with inflammatory arthritis. Thirty-five patients were pain free at the latest follow-up, and 6 reported mild to occasional pain with repetitive activities. The overall satisfaction rate was 40 of 49 patients (81%). Grip strength recovered to 86% of that of the contralateral side. Apposition key and opposition pinch strength improved to 92% and 95%, respectively, of those of the contralateral hand. Pyrolytic carbon thumb arthroplasty may prove to be an acceptable option for the treatment of TM, although a high complication rate was observed in this early cohort, with many cases of subluxation attributed to the creation of a too shallow trapezial cup. Further comparative studies are warranted. Therapeutic IV.

Analyse de la tête du nerf optique par microscope confocal à balayage laser (CSLO) de larges excavations papillaires comparée aux normales

To comparatively evaluate the optic nerve head (ONH) using the confocal scanning laser ophthalmoscope (CSLO) in normal eye subjects (NE) versus big cup (BC) patients. A total of 83 NEs (43 subjects) and 44 BC eyes (22 patients) were evaluated in this prospective study. The ONH was imaged using the CSLO (HRT-II; Heidelberg Engineering, Heidelberg, Germany). Disc area, cup area, rim area, rim volume (horizontal integrated rim volume), cup/disc ratio, and cup volume were evaluated. Additionally, cup depth and retinal nerve fiber layer thickness (RNFL th) and csa (RNFL csa) of the ONH were also measured. These ONH parameters were compared between normal subjects and eyes with a big cup. We used the t test for statistical analysis. The mean age was 46 and 44 years in the NE and BC groups, with a sex ratio of 1.26 and 0.69 (p=0.381), respectively. There was a significant difference in disc area (2.07+/-0.38, 2.73+/-0.45, p<0.01), cup area (0.52+/-0.8, 1.26+/-0.3, p<0.01), cup volume (0.14+/-0.14, 0.44+/-0.16, p<0.01), cup/disc ratio (0.24+/-0.1, 0.69+/-0.1, 0.46+/-0.06, p<0.01), Me cup disc (0.24+/-0.1, 0.37+/-0.1, p<0.01), rim volume (0.44+/-0.1, 0.34+/-0.09, p<0.01), rim area (1.56+/-0.27, 1.45+/-0.27, p=0.345), RNFL th (0.28+/-0.05, 0.23+/-0.05, p<0.001) and CSM-0.19+/-0.14,-0.08+/-0.06, p<0.001), RNFL csa (1.43+/-0.25, 1.37+/-0.29, p=0.849) in normal vs big cup eyes, respectively. There is correlation between the cup and disc areas. Parameters evaluating the retinal nerve fiber were comparable in the two groups, except the RNFL thickness, which was lower in the BC group. This may be explained by the larger surface of the optic disc in this group. HRT parameters might be part of the criteria favoring the physiologic character of big cups.

Agreement between optical coherence tomography and digital stereophotography in vertical cup-to-disc ratio measurement

Given the increasing popularity of optical coherence tomography in the diagnosis of glaucoma, we aimed to assess agreement between StratusOCT and stereophotography in measuring the vertical cup-to-disc ratio (VCDR) and examine whether it can be improved by changing the StratusOCT cup-offset. In group 1 (79 eyes), VCDR measurements obtained by StratusOCT (using the default cup-offset of 150 microm above the retinal pigment epithelium) and stereophotography were compared. For each eye, the cup-offset was moved upward or downward until the difference disappeared and an adjusted cup-offset was identified. In group 2 (41 eyes), the stereophotography VCDR was compared to the StratusOCT value obtained by using the mean adjusted cup-offset. StratusOCT was used to classify optic disc cups as shallow or deep. In group 1, StratusOCT overestimated VCDR in optic discs with deep cups and underestimated it in those with shallow cups (p < 0.0001). Mean adjusted cup-offsets were 72.8 +/- 92 microm and 191.6 +/- 70 microm for eyes with deep and shallow cups. The 95% limits of agreement (LOA) ranged from -0.21 to 0.17. In group 2, the adjusted cup-offsets enabled us to eliminate the statistical differences in VCDR measurements and improve the 95% LOA (from -0.13 to 0.14). Adjusting the StratusOCT cup-offset according to the cup depth improves agreement between StratusOCT and stereophotography in measuring the VCDR.

Morphologic Study of Mandibular Outer Cortex Osteotomy

The purpose of this study was to illustrate the morphologic changes of the mandible after outer cortex osteotomy. Ten patients had undergone mandibular outer cortex osteotomy. By using the true-up and dissection techniques based on three-dimensional spiral computed tomography, variables of effect and bone regeneration were evaluated 6 months postoperatively. Concavity could be seen in the area from which the mandibular outer cortex had been removed 6 months postoperatively, especially at the external oblique line region. The average cup depth was 3.64 +/- 1.67 mm postoperatively. Diminution of bone volume was 1.7 +/- 0.5 percent for the entire mandible and 55 +/- 9 percent for the local area 6 months postoperatively. Bone regeneration could be seen in the area from which the mandibular outer cortex had been removed. Compared with immediately postoperatively, the ratio of neoformative bone was 84.6 +/- 7.3 percent 6 months postoperatively. The main region of bone regeneration was the mandibular angle. Mandibular outer cortex osteotomy is an effective technique for reducing the width of the lower face. Masseter muscular movement should be restricted postoperatively to prevent hyperostosis at the angle area.

Relationships between central corneal thickness and optic disc topography in eyes with glaucoma, suspicion of glaucoma, or ocular hypertension

To identify relationships between central corneal thickness (CCT) and optic disc topography, as determined by scanning laser ophthalmoscopy (SLO), for patients seen in a specialist glaucoma service. 272 eyes of 144 patients with primary open angle glaucoma (POAG; n = 71), normal tension glaucoma (NTG; n = 50), ocular hypertension (OH; n = 48) and those considered to be suspicious for glaucoma (GS; n = 103) underwent ultrasonic pachymetry and optic disc topography by SLO. Correlations between CCT and SLO parameter values were identified. A Bonferroni correction for multiple comparisons was performed and a p value of <0.0042 was considered significant. Mean CCT values were 533 mum (POAG), 530 mum (NTG), 550 mum (GS), and 565 mum (OH). As a group the GS and OH eyes had significantly thicker CCT values than eyes with POAG. In addition, the NTG eyes had significantly thinner CCT values than GS and OH eyes. Overall multiple SLO parameters correlated with CCT even after accounting for co-variance with age, refraction and inclusion of both eyes. Sub-group analysis indicated that 'optic disc rim area' positively correlated with CCT (r = 0.378) and 'cup to disc area ratio' negatively correlated with CCT (r = -0.370) in the POAG group. In the GS group the parameter 'area below reference' (a measure of cup volume) and 'mean cup depth' had negative correlations with CCT (r = -0.297 and -0.323) indicating that eyes with thinner than average corneal thickness measurements had larger and deeper cups. Thinner corneas appear to be associated with larger and deeper optic disc cups in the eyes of patients seen in a specialist glaucoma service.

Heidelberg retina tomograph parameters of the optic disc in eyes with progressive retinal nerve fibre layer defects

To determine the Heidelberg retina tomograph (HRT) parameters that identify glaucomatous changes in optic nerve head (ONH) topography associated with progression of retinal nerve fibre layer (RNFL) defects. A total of 68 eyes with open-angle glaucoma were included in this retrospective study: 34 eyes showed progression of an RNFL defect during the follow-up period and 34 eyes did not. Successful RNFL photographs and scanning laser tomography examinations with the HRT were taken in all patients at each of three visits. The change in HRT parameter values during follow-up was calculated. Progression of the RNFL defect was statistically significantly correlated (p = 0.049) with only one topographic ONH parameter, the cup shape measure. The best combination of two parameters (p = 0.009) included the maximum cup depth and the linear cup : disc area ratio; the best combination of three parameters (p = 0.007) included the maximum cup depth, the linear cup : disc area ratio and the horizontal cup : disc area ratio. Sensitivity and specificity values were 52.9% and 73.5%, respectively, for the cup shape measure, 70.6% and 73.5%, respectively, for the two-parameter combination, and 76.5% and 79.4%, respectively, for the three-parameter combination. The areas under the receiver operating characteristic curve were 0.617, 0.724 and 0.753, respectively. The results indicate that the HRT parameters may be used to detect small ONH changes associated with progression of the RNFL defect. With the exception of the cup shape measure, the parameters which provide the best correlation with progression differ from those considered optimal for recognizing the presence or absence of glaucoma.

Estudio de los parámetros de la cabeza del nervio óptico en sujetos normales, hipertensos oculares y glaucomatosos obtenidos mediante láser confocal de barrido (Heidelberg Retina Tomograph II)

To compare the optic nerve parameters measured by confocal scanning laser in normal, ocular hypertensive and glaucomatous eyes; and in groups of ocular hypertensive eyes, classification of these according to the optic nerve appearance and to short-wavelength automated perimetry (SWAP) results. 101 eyes of 101 normal subjects, 247 eyes of 247 ocular hypertensive subjects and 102 eyes of 102 glaucomatous subjects were studied. Subjects were classified based on intraocular pressure and standard automated perimetry (AP) performance. Hypertensive subjects were classified into ocular hypertensive and preperimetric glaucoma, and into ocular hypertensive with normal SWAP and hypertensive with pathological SWAP findings. Every patient underwent evaluation of the optic nerve, AP, SWAP and confocal scanning laser ophthalmoscopy (HRT II), resulting in the acquisition of topographic parameters of the optic nerve, which were then compared between the different groups. Significant differences (p<0.05) were found between normal subjects and glaucomatous eyes in all optic nerve parameters except disc area (2.23/2.1), height variation contour (0.41/0.39) and average variability (0.05/0.04). Ocular hypertensive eyes showed an overlap when compared with normal and glaucoma groups. No differences were found between normal subjects and those with ocular hypertension in mean retinal nerve fiber layer thickness (0.24/0.24) or between those with ocular hypertension and glaucoma in mean cup depth (0.28/0.3). Nevertheless, when those with ocular hypertension were segregated based on clinical evaluation of optic nerve or SWAP performance, the ability to define the presence of structural glaucoma damage improved significantly. HRT enables moderate discrimination between normal, ocular hypertensive and glaucoma subjects. The use of diagnostic tests to detect early glaucomatous damage (such as short-wavelength automated perimetry) in ocular hypertensive eyes improves the ability of HRT to discriminate glaucoma.

Finite element analysis of sheet Hydromechanical forming of circular cup

Sheet hydroforming is a process of converting flat sheet into desired component geometry by using water pressure in a controlled manner. This paper dealt with sheet Hydromechanical forming (SHMF) of circular cup. In this process, blank is first placed on the lower die (a fluid chamber combined with draw ring) and then after sealing the blank between blank holder and draw ring, punch progresses to deform the blank. Pressure of the fluid chamber is also increased simultaneously with the punch progression. The present work endeavours to understand the effect of strain hardening exponent, anisotropy ratio and interfacial friction between blank and tools surfaces for different modes of deformation––stretching to drawing mode on sheet Hydromechanical forming of circular cups. A finite element (FE) model was developed for simulating the SHMF process using dynamic explicit, commercial code, LsDyna. The model after experimental validation used for studying the effect of above parameters on the process. The analysis reveals that higher cup depth with minimum thinning for forming dominated by stretching mode can be achieved with material of higher anisotropy ratio, strain hardening exponent by using a rough punch and effective lubrication at blank-die–blank holder interfaces. On the other hand in case of drawing as mode of deformation, thinning is influenced mainly by interfacial friction condition between blank and tool surfaces as compared to material properties.

Optic Disc and Peripapillary Morphology in Unilateral Nonarteritic Anterior Ischemic Optic Neuropathy and Age- and Refraction-Matched Normals

To compare optic disc morphologic features and peripapillary retinal nerve fiber layer (RNFL) thickness between the unaffected eyes of patients with unilateral nonarteritic anterior ischemic optic neuropathy (NAION) and their affected eyes and the eyes of age- and refraction-matched normal control subjects. Cross-sectional comparative study. Thirty-one patients with unilateral NAION and 62 age- and refraction-matched normal control subjects. Optic disc morphologic features and peripapillary RNFL thickness were evaluated in both eyes of patients with unilateral NAION and in one randomly chosen eye of the normal control subjects. Optic disc and cup parameters were measured using the Heidelberg Retina Tomograph II (Heidelberg Engineering GmbH, Dossenheim, Germany), and RNFL thickness was measured by scanning laser polarimetry with variable corneal compensation (GDx VCC; Carl Zeiss Meditec, Dublin, CA). There was no significant difference in the disc area between the NAION affected eyes and the unaffected fellow eyes. The cup area, cup-to-disc area ratio, cup volume, and cup shape measure were greater, whereas the peripapillary RNFL thickness was smaller in the former than the latter (P = 0.001 to approximately 0.043). When the unaffected eyes of patients with NAION and the age- and refraction-matched normal control eyes were compared, the disc area, cup area, cup-to-disc area ratio, cup volume, mean cup depth, and cup shape measure were smaller in the former (P = 0.0006 to approximately 0.03); there was no significant difference in the RNFL thickness between the two (P>0.06). A comparison of the eyes with NAION and the fellow eyes indicated that the cup was slightly larger in the former than in the latter, suggesting the acquired enlargement of the cupping after NAION develops. A comparison of the unaffected fellow eyes in patients with NAION and the age- and refraction-matched normal control eyes suggested that a smaller disc area and smaller cupping were predisposing risk factors for the development of NAION.

Corneal Hysteresis but Not Corneal Thickness Correlates with Optic Nerve Surface Compliance in Glaucoma Patients

To investigate relationships between acute intraocular pressure (IOP)-induced optic nerve head surface deformation and corneal hysteresis and thickness in glaucomatous and nonglaucomatous human eyes. This was a prospective experimental study of 100 subjects (38 with glaucoma, 62 without glaucoma). Data collected included spherical equivalent, optic disc diameter, central corneal thickness (CCT), axial length, cylinder, Goldmann IOP, Pascal IOP, and ocular pulse amplitude and ocular response analyzer (ORA) measurements of corneal hysteresis (CH). Elevation of IOP was induced in the right eye of each subject with a modified LASIK suction ring to an average of 64 mm Hg for less than 30 seconds. Heidelberg Retina Tomography II (HRT) was used to map the optic nerve surface before and during IOP elevation. Mean cup depth was calculated using built-in HRT data analysis software. Change in optic disc depth during IOP elevation was calculated for all right eyes, and tests for correlation with the parameters listed were performed. Both CH and CCT were lower in the glaucoma group (8.8 mm Hg and 532 microm) than in the control group (9.6 mm Hg, P = 0.012; 551 microm, P = 0.011, respectively). There were no statistically significant differences in spherical equivalent, cylinder, axial length, optic disc size, or ocular pulse amplitude between the glaucoma and the control groups. There was no difference between the amount of IOP elevation between the two groups (P = 0.41), and the average difference in mean cup depth between baseline (mean cup depth, 247 microm) and during IOP elevation was 33 microm (29.8 microm in glaucoma and 36.1 microm in control; P = 0.5). Multiple variable analysis, controlling for age and sex, showed that CH was correlated with mean cup depth increase (P = 0.032). This relationship persisted (P = 0.032) after controlling for glaucoma status in addition to age and sex. Other factors, including CCT (P = 0.3), axial length (P = 0.9), ocular pulse amplitude (P = 0.22), and spherical equivalent (P = 0.38), were not significant in this model. In the glaucoma patients but not the control patients, CH but not CCT or other anterior segment parameters was associated with increased deformation of the optic nerve surface during transient elevations of IOP. (ClinicalTrials.gov number, NCT00328835.).

Study of three-dimensional spacer fabrics: Molding properties for intimate apparel application

Three-dimensional spacer fabrics are used for sports textiles and foundation garments such as bra cups and pads for swimwear. Very often these spacer fabrics are molded into a desirable shape in order to fit with consumers’ body contour. Thermal–mechanical properties of the spacer fabric are greatly affecting the molding properties and shape conformity of the molded spacer product. In this study, five different spacer fabrics were molded to a desirable bra cup shape with 6 cm cup depth (equivalent to a size 38B's bra). The optimal molding conditions including molding temperature and molding time for each spacer fabric were found. It was shown that not all spacer fabrics can be molded to a desired cup shape. The thermal–mechanical properties determined by TMA revealed that the optimal molding conditions and compressive strain of molded spacer fabrics are closely related to the material used as spacer yarn, the density of spacer yarn, and the elongation and recovery of the spacer fabric. This experimental work provides the industry with a greater insight into the behavior of these environmentally friendly spacer fabrics, and useful information for selecting a suitable spacer fabric for the molding purpose.

Caractéristiques cliniques et épidémiologiques du glaucome chronique à angle ouvert

This retrospective study examined the files of patients who consulted at the Women's and Children's Hospital of Yaoundé in Cameroon from March 2003 through December 2006. The main objective was to determine the epidemiological and clinical characteristics of patients diagnosed with chronic open-angle glaucoma (COAG). Of 8,123 files reviewed, 184 patients (54.3% women) were diagnosed with COAG, all but one binocular. Their mean age was 62.2+/-13.01 years. According to the WHO definition of blindness, the rate of bilateral blindness was 34.2%, that of unilateral blindness 21% and low vision 17.4%. Significant statistic correlations were observed between the cup depth of the optic disc and visual acuity on one hand, and between the level of intraocular pressure and cup depth on the other, p=0.0001. Approximately 90.67% of the eyes with glaucoma had high pressure and 9.23% normal pressure. COAG is a major cause of visual disability in Cameroon. Intraocular pressure is an important risk factor, but its positive predictive value for the impairment of optic disc fibres is low (R=0.29); other factors (apoptosis and ischemia of the optic disc) are associated with it. Advanced strategies for early diagnosis of COAG are essential, for this disease is an important cause of blindness. Such programmes would significantly delay the onset of visual disabilities.

Relationship between Central Corneal Thickness and Parameters of Optic Nerve Head Topography in Healthy Subjects

To investigate the relationship between central corneal thickness (CCT) and topographic parameters of optic nerve head (ONH) in healthy eyes. Right eyes of 208 healthy subjects between 40 and 59 years of age with refractive error less than 1 D were enrolled in this cross-sectional study. Ultrasonic pachymeter was used to measure CCT, and the ONH parameters were obtained by using confocal scanning laser ophthalmoscope. Relationship of various topographic parameters to age and sex were also investigated. For statistical analysis Student t test, analysis of variance, Pearson and Spearman test, and partial correlation coefficients were used. Mean CCT of subjects was 540.71+/-35.53 micronm (462-621 micronm), and the mean disc area was 2.37+/- 0.44 mm2 (1.28-3.66 mm2). CCT showed negative correlations to disc area, rim area, rim volume, and retinal nerve fiber layer (RNFL) area. These correlations were found to be stronger in females. Negative correlations were demonstrated between age and the mean cup depth, maximum cup depth, RNFL thickness, and RNFL cross sectional area. Women had lesser rim volumes, but bigger cup to disk (C/D) area and linear C/D ratios compared to those of men. In addition to its effect in the accuracy of intraocular pressure measurements, CCT has a structural relationship with the ONH in healthy nonglaucomatous eyes. Therefore, its effect on disc area might be especially important to explain the structural strength of the ONH in the pathogenesis of glaucoma.

Quantitative depth analysis of optic nerve head using stereo retinal fundus image pair

Depth analysis of the optic nerve head (ONH) in the retinal fundus is important for the early detection of glaucoma. In this study, we investigate an automatic reconstruction method for the quantitative depth measurement of the ONH from a stereo retinal fundus image pair. We propose a technique to obtain the depth value from the stereo retinal fundus image pair, which mainly consists of five steps: 1. cutout of the ONH region from the stereo retinal fundus image pair, 2. registration of the stereo image pair, 3. disparity measurement, 4. noise reduction, and 5. quantitative depth calculation. Depth measurements of 12 normal eyes are performed using the stereo fundus camera and the Heidelberg Retina Tomograph (HRT), which is a confocal laser-scanning microscope. The depth values of the ONH obtained from the stereo retinal fundus image pair were in good accordance with the value obtained using HRT (r=0.80+/-0.15). These results indicate that our proposed method could be a useful and easy-to-handle tool for assessing the cup depth of the ONH in routine diagnosis as well as in glaucoma screening.

Topographic Comparison of the Visual Function on Multifocal Visual Evoked Potentials with Optic Nerve Structure on Heidelberg Retinal Tomography

The authors' objective was to compare the visual field obtained using multifocal visual evoked potential (mfVEP) testing with the optic nerve parameters of Heidelberg retinal tomography (HRT; Heidelberg Engineering, Heidelberg, Germany; software version 2.01) in primary open-angle glaucoma (POAG) patients and normal controls and to determine which parameters correlate with visual function. Cross-sectional study. Eighty-one eyes of 42 adult POAG patients and normal controls between the ages of 40 and 80 years, of which 35 patients (67 eyes; mean age+/-standard deviation [SD], 68+/-10 years) had POAG, and 7 individuals who served as normal controls (14 eyes; mean age+/-SD, 61+/-10 years) were included. A monocular mfVEP test, the AccuMap (Opera software version 2.0; ObjectiVision Pty. Ltd., Sydney, Australia), with a 58-sector pattern-reversal dart board array was recorded in both eyes per patient. These patients underwent the HRT 2 and mfVEP tests within 3 months of each other. Amplitudes in the superior hemisphere of the mfVEP trace were compared with the HRT parameters in the inferior hemisphere of the HRT and vice versa using mixed effects regression models. Amplitudes on the superior hemisphere of the mfVEP recordings showed a significant direct correlation with rim-to-disc area ratio (P = 0.0037), rim volume (P = 0.0421), and mean retinal nerve fiber layer (RNFL) thickness (P = 0.0016) and a significant inverse correlation with cup area (P = 0.0009) and cup-to-disc area ratio (P = 0.0037) in the inferior hemisphere of the HRT results. Amplitudes on the inferior hemisphere showed a significant direct correlation with rim-to-disc area ratio (P = 0.036) and a significant inverse correlation with cup area (P = 0.0007), cup-to-disc area ratio (P = 0.036), cup volume (P<0.0001), and mean cup depth (P = 0.0012) in the superior hemisphere of the HRT results. Results from mfVEP and HRT showed correlation between visual function and optic nerve structure.

Effect of the blank holder force on drawing of aluminum alloy square cup: Theoretical and experimental investigation

In this study, the influence of AA5754-O material, an aluminum alloy, in forming the blank holder force (BHF) in deep drawing process has been investigated. For this purpose, a new experimental system has been prepared. By means of this system, deep drawing process can be implemented through applying variable forces in computer-controlled manner on the blank holder and sheet plate. The numerical model of forming with deep drawing process has been built up and analyzed via the LS-DYNA software. Cup depths, tearing and wall thickness variations of the experimental and numerical results have been compared. It has been observed that no earing and wrinkling have occurred in BHF's between 1.3 and 8 MPa in square deep drawing process, and that tears have occurred in forces exceeding 18 MPa. It has further been observed that the best forming has occurred at 5 MPa, and that the numerical and experimental model developed is in harmony with one another at a rate of 85%.

Heidelberg Retinal Tomography of Optic Disc and Nerve Fiber Layer in Singapore Children: Variations with Disc Tilt and Refractive Error

To evaluate the relationships in Singapore school children between optic nerve head parameters and retinal nerve fiber layer thickness images by using the Heidelberg Retinal Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany) and determining optic disc tilt and refractive error. This was a cross-sectional study involving 316 children 11 and 12 years of age (163 girls and 153 boys) selected randomly from one of the three schools in the Singapore Cohort study of Myopia. A total of 13 optic disc parameters were obtained from HRT images acquired before cycloplegia. Refractive errors were measured by cycloplegic autorefraction. The presence of optic disc tilt or otherwise was determined by two independent assessors using stereoscopic viewing of retinal photographs. Of the 316 children, 142 had tilted discs. The tilting of optic discs was associated with a smaller disc, rim or cup area measurements, cup-to-disc area ratios, cup volumes or cup depths, but with a larger measured rim volume, rim-to-disc area ratios, height variation of the contour, retinal nerve fiber layer thicknesses or volumes, and a more negative cup shape measure (all P < 0.001). Decreased maximum cup depths were significantly associated with longer axial lengths (P < 0.001), but were not associated with spherical equivalent (P = 0.693). These associations remained only in children without tilted discs, but were no longer significant in those with tilted discs. Other HRT parameters were not associated with axial lengths or myopic status. Optic nerve head parameters and retinal nerve fiber layer thickness measured by the current HRT algorithms are strongly influenced by the tilting of the optic nerve head, but not by refractive errors or axial length.

The Acute Morphologic Changes That Occur at the Optic Nerve Head Induced by Medical Reduction of Intraocular Pressure

The mechanical theory of glaucoma postulates that raised intraocular pressure (IOP) causes laminar distortion resulting in damage to axons at the optic nerve head. There is some evidence that the change in morphology may occur over a short time course. The aim of this paper was to detail the acute morphologic changes at the optic nerve head when IOP was lowered with medical therapy in a clinical population. Subjects referred to the glaucoma clinic that had a documented IOP of over 28 mm Hg, on no treatment, in one or both eyes were included. Tonometry, pachymetry, and scanning laser ophthalmoscopy were performed before and after lowering IOP with topical apraclonidine and oral acetazolamide. The significance of change in outcome variables was assessed using a paired t test allowing for dependence within subjects and, for sensitivity, with a nonparametric Wilcoxon signed-rank test. Data were obtained from 38 eyes of 19 patients with a mean age of 67 years. After lowering IOP for only 1 hour, there was a significant decrease in mean cup volume (mean change in volume below surface 26.8 microm3, P< or =0.001) and mean cup depth (13.8 microm, P<0.01), there being a corresponding increase in mean rim area (37.3 microm2, P<0.034). There was no statistically significant change in central corneal thickness after administration of the IOP lowering medications. In the present study, it was shown that acute and statistically significant alterations in optic disc morphology occur when IOP is lowered medically with a combination of topical apraclonidine and systemic acetazolamide. The technique, therefore, may be useful to further investigate subgroups of glaucomatous eyes and test etiologic hypotheses.