Cup Depth Research Articles

Heidelberg retina tomography II parameters in evaluating high- and normal-pressure glaucoma progression

Heidelberg retina tomography II (HRT II) haves been employed to quantitatively assess the topography of optic discs in eyes with high-pressure glaucoma (HPG) and normal-pressure glaucoma (NPG), in order to determine which of global and segmental optic disc parameters will prove to be most suitable for monitoring the progression of these two conditions. The results of 73 eyes of 73 patients with HPG and NPG were analyzed in relation to age, refractive error, quality of HRT images and stereometric parameters. A statistically significant difference (p < 0.05) between the global baseline and follow-up results was found in: rim volume, maximum cup depth and cup shape measure (in the HPG group), and C/D ratio, cup volume, rim volume and cup shape measure (in the NPG group). The baseline and follow-up results of the retinal nerve fiber layer in the temporal and inferotemporal sectors show a significant difference in both groups. Several HRT stereometric parameters are useful for monitoring the progression of changes of the optic disc and local retina in eyes with HPG and NPG. Both segmental and global scanning is of importance in glaucoma progression analysis.

Influence of anisotropy parameter on deep drawing of tailor welded blanks of low-carbon steels

The influence of difference in thickness, material properties and the weld zone on deep drawing and stretch forming behavior of tailor welded blanks is a critical laboratory scale study before implementation in car body design. Mostly, various low-carbon steel sheets are used for fabrication of tailor welded blanks due to their excellent weldability and formability, and these steel sheets have high normal and planar anisotropy from preprocessing stage due to large deformation cold rolling. In this study, two different tailor welded blanks and one laser welded blank of similar material combination were fabricated by laser welding of interstitial-free, interstitial-free high-strength and high-strength low-alloy steels. Transverse tensile testing of the laser welded blanks of similar material combination (interstitial free–interstitial free) and two tailor welded blank specimens (interstitial free–interstitial free high strength and interstitial free–high strength low alloy) were conducted to evaluate the weld quality in terms of strength and failure location. The effect of anisotropy on formability of tailor welded blanks was investigated in terms of cup depth and fracture location in cylindrical deep drawing process. Finite element simulations of the deep drawing process were conducted using the commercial available nonlinear solver, RADIOSS. It was observed that the Lankford anisotropy parameter, R-value, influences the thickness distribution, weldline movement and failure location in tailor welded blanks.

Correlation Between Optic Nerve Head Parameters, RNFL, and CCT in Patients with Bilateral Pseudoexfoliation Using HRT-III

Background: It is well-established that eyes with pseudoexfoliation syndrome (PXS) have higher intraocular pressure (IOP). Early diagnosis of preperimetric glaucoma will assist with better management of these patients. The aim of this study is to evaluate the optic nerve head (ONH) parameters and retinal nerve fiber layer (RNFL) thickness in subjects with bilateral PXS, bilateral pseudoexfoliative glaucoma (PXG) and normal, correlating these results with central corneal thickness (CCT). Design: This is a cross-sectional, case control study. All participants were from the Department of Ophthalmology, Athens University Medical School. Participants: A total of 55 eyes from 55 patients with PXS (27 eyes from 27 patients with PXG and 28 eyes from 28 normal subjects) were studied. Methods: Topographic measurements of the ONH and peripapillary RNFL thickness were performed using a confocal scanning laser ophthalmoscope (the Heidelberg Retina Tomograph-III). The outcomes were correlated with the CCT of the subjects. Main Outcome Measures: PXS subjects and age-matched normal subjects did not differ significantly in ONH parameters. RNFL thickness was significantly lower in the PXS group compared with the normal group, but there was not a statistically significant difference with the PXG patients. Regarding the correlation with CCT, the PXG group showed negative correlation with mean (p = 0.027) and max cup depth (p = 0.031), while PXS subjects revealed a positive correlation with RNFL thickness (p = 0.032). Conclusions: Our study showed that PXS subjects may be at greater risk of RNFL thinning, presenting a statistically significant positive association of the latter parameter with the CCT.

Topographic Optic Disc Changes After Successful Trabeculectomy Evaluated Using Spectral Domain Optical Coherence Tomography

To investigate topographic optic disc changes after surgical intraocular pressure (IOP) reduction in adults with open angle glaucoma (OAG). Optic discs of patients with advanced primary open angle or exfoliation glaucoma were imaged using optical coherence tomography within 1 week before trabeculectomy. Patients were rescanned 1 week, 1 month, and 1 year after surgery. Maximum cup depth (MCD), and average cup depth (ACD) were calculated. Twenty-two eyes from 20 patients (age, 70.5 ± 10.6 years; average mean defect of visual field, -15.0 ± 9.8 dB) were followed up for 1 year. The IOP decreased from 22.1 ± 2.8 mmHg at baseline to 11.5±2.6 mmHg 1 year following surgery (P<0.001). One-week and 1-month postoperative IOPs were 11.2 ± 2.8 and 11.2 ± 3.5 mmHg, respectively (P<0.001). Compared to the baseline values (356 ± 172 μm), postoperative ACD showed a significant decrease at 1 week (312 ± 164 μm; P<0.001) and 1 month (338 ± 175 μm; P=0.007) after surgery, but not at 1 year (339 ± 176 μm; P=0.354). Similarly, MCD significantly decreased from baseline (477 ± 190 μm) 1 week (431 ± 203 μm; P=0.029) and 1 month (448 ± 198 μm; P=0.047) after the surgery, but not after 1 year (479 ± 188 μm; P=1.0). Trabeculectomy reduces IOP in eyes with advanced OAG, which induces topographic optic disc changes. Such optic disc changes became less pronounced over time and were no longer detectable 1 year after surgery.

Measurement and analysis of optic disc parameters in Mongolian and Han healthy subjects with or without family history of glaucoma

Objective To measure optic disc parameters in Mongolian and Han healthy subjects with or without family history of glaucoma,to explore the causes of the differences and their significance in the diagnosis of early glaucoma.Methods Fifteen healthy Mongolian individuals (30 eyes),30 healthy Han individuals (60 eyes) with a family history of open-angle (30 eyes) or angle-closure (30 eyes) glaucoma,and 45 healthy Han individuals (90 eyes) without a family history of glaucoma were enrolled in this study.The 45 healthy Han individuals without a family history of glaucoma included three age-groups:20 to 29 years old group,30 to 39 years old group and 40 to 49 years old group,each group have 15 subjects (30 eyes).Thirteen parameters were measured by Heidelberg retina tomography (HRT) for all subjects,including disc area,cup area,rim area,cup volume,rim volume,cup/disc area ratio,linear cup/disc ratio,mean cup depth,maximum cup depth,cup shape,disc height variation contour,mean retinal nerve fiber layer (RNFL) thickness and optic nerve fiber layer cross-sectional area.The results were analyzed and compared between the above groups.Results There was no statistically significant (t=0.791,P=0.132) of the height variation contour between Mongolian and Han without a family history of glaucoma (20 to 29 years old) group.The other parameters of Mongolian were smaller than Han without a family history of glaucoma (20 to 29 years old) group,but the difference was not statistically significant (t=-1.039,-0.799,-0.840,-1.108,-0.956,-0.695,-0.931,-1.099,-1.074,-0.580,-0.204,-1.425; P＞ 0.05).The parameters in Han with a family history of open-angle glaucoma group were bigger than Han without a family history of glaucoma (30 to 39 years old) group.The differences were statistically significant for disc area,cup area,rim area,cup volume,rim volume,cup area ratio,linear cup/disc ratio,mean cup depth,cup shape measure,nerve fiber layer cross-sectional area (t =4.758,3.187,2.544,2.674,1.798,3.676,2.721,2.715,2.510,2.373; P＜0.05),but were not statistically significant for maximum cup depth,disc height variation contour and mean RNFL thickness (t=1.649,1.565,0.767; P＞0.05).Most parameters in Han with a family history of angle-closure glaucoma group were the same as that in Han without a family history of glaucoma (40 to 49 years old) group,including cup area,rim area,cup volume,rim volume,cup/disc area ratio,linear cup/disc ratio,mean optic cup depth,maximum cup depth,cup shape,disc height variation contour,mean RNFL thickness,optic nerve fiber layer cross-section (t=1.201,1.697,1.000,0.516,0.740,-0.172,-0.070,-0.972,1.530,-0.390,-0.091,0.659; P＞ 0.05) ; but the difference of disc area between these 2 groups was statistically significant (t=2.224,P＜0.05).Conclusions The family history of glaucoma can change the optic disc parameters of healthy individuals,especially those with a family history of open-angle glaucoma.There is no difference of optic disc parameters between healthy Mongolian and Han subjects. Key words: Optic disk/anatomy & histology; Optic disk/physiopathology; Glaucoma/diagnosis

Valsalva manoeuver, intra‐ocular pressure, cerebrospinal fluid pressure, optic disc topography: Beijing intracranial and intra‐ocular pressure study

To assess whether a Valsalva manoeuver influences intra-ocular pressure (IOP), cerebrospinal fluid pressure (CSF-P) and, by a change in the trans-laminar cribrosa pressure difference, optic nerve head morphology. In the first part of the study, 20 neurological patients (study group 'A') underwent measurement of IOP and lumbar CSF-P measurement in a lying position before and during a Valsalva manoeuver. In the second study part, 20 healthy subjects (study group 'B') underwent ocular tonometry and confocal scanning laser tomography of the optic nerve head before and during a Valsalva manoeuver. During the Valsalva manoeuver in study group 'A', the increase in CSF-P by 10.5±2.7mmHg was significantly (p<0.001) higher than the increase in IOP by 1.9±2.4mmHg. The change in CSF-P was not significantly (p=0.61) correlated with the change in IOP. During the Valsalva manoeuver in study group 'B', IOP increased by 4.5±4.2mmHg and optic cup volume (p<0.001), cup/disc area ratio (p=0.02), cup/disc diameter ratio (p=0.03) and maximum optic cup depth (p=0.01) significantly decreased, while neuroretinal rim volume (p=0.005) and mean retinal nerve fibre layer thickness (p=0.02) significantly increased. The Valsalva manoeuver-associated short-term increase in CSF-P was significantly larger than a simultaneous short-term increase in IOP. It led to a Valsalva manoeuver-associated decrease or reversal of the trans-laminar cribrosa pressure difference, which was associated with a change in the three-dimensional optic nerve head morphology: optic cup-related parameters decreased and neuroretinal rim-related parameters enlarged. These findings may be of interest for the pathogenesis of glaucomatous optic neuropathy.

Evaluation of the Optic Nerve Head in Glaucoma.

ABSTRACTGlaucoma is an optic neuropathy leading to changes in the intrapaillary and parapaillary regions of the optic disk. Despite technological advances, clinical identification of optic nerve head characteristics remains the first step in diagnosis.Careful examination of the disk parameters including size, shape, neuroretinal rim shape and pallor; size of the optic cup in relation to the area of the disk; configuration and depth of the optic cup; ratios of cup-to-disk diameter and cup-to-disk area; presence and location of splinter-shaped hemorrhages; occurrence, size, configuration, and location of parapapillary chorioretinal atrophy; and visibility of the retinal nerve fiber layer (RNFL) is important to differentiate between the glaucomatous and nonglaucomatous optic neuropathy.How to cite this article: Gandhi M, Dubey S. Evaluation of the Optic Nerve Head in Glaucoma. J Current Glau Prac 2013;7(3):106-114.

Tomographic characteristics of optic nerve head on Heidelberg retina tomograph III in healthy Chinese subjects

Background Normal adult optic disc rim width follows inferior ≥ superior ≥ nasal ≥ temporal (ISNT) rule.Analysis of the optic disc structural parameters with Heidelberg retina tomograph (HRT) can understand whether ISNT principle is suitable to other optic disc structure parameters.Objective This study was to investigate the characteristics of optic nerve head structure parameters in normal Chinese adults.Methods The parents of twins who participated Guangzhou Twin Eye Study were enrolled in Zhongshan Ophthalmic Center from 2006 June to 2011 August.All subjects received the routine eye examinations,including visual acuity,slit lamp microscope,direct ophthalmoscope examination,auto-refraction examination and HRT Ⅲ examination.All data from the right eyes were collected and analyzed.HRT values from different quadrants of optical nerve head were compared with one-way analysis of variance,and the multiple comparison between quadrants was carried out by Bonferroni test.The differences of optical nerve head parameters in different gender were analyzed using independent sample t test and Bland-Altman test.Results In this study,1672 eyes of 1672 subjects were included,with the 759 male and 913 female persons and average age of (41.8±5.3)years.No significant differences were seen in the disc area (DA)between the superior and inferior,as well as the nasal and temporal quadrants among the subjects (P＞0.05).In addition,there were not significantly different in the rim area (RA) between the superior and nasal disc as well as the rim volume (RV) among the inferior,superior and nasal disc (P＞O.05).However,significant differences were found in the cup area (CA),cup/disk area ratio (C/DAR),cup volume (CV),mean cupdepth (MCD),maximum cup depth (MxCD),height variation contour (HVC),cup shape measure (CSM),mean retinal nerve fiber layer thickness (mRNFLT) and retinal nerve fiber layer cross section area (RNFLcsa) among the different quadrants (P＜0.001).The local differences from only DA and RA complied with an ordination of the ISNT rule.The values of DA,CA,C/DAR,CV,MCD,MxCD from male individuals were higher,but those of the RV,HVC,mRNFLT RNFLcsa were lower in comparison with female individuals.Nevertheless,all the differences were ＜ 0.1 with a maximal mean difference in DA and CA (both 0.07 mm2).Conclusions The optical nerve head configurations measured by HRT have different distributing characteristics in four quadrants in normal adults.Most parameters show the higher values in the inferior and superior than those in nasal and temporal of disc,but DA and RA meet ISNT rule.The differences of most parameters between male and female subjects can be ignored. Key words: Bio-metrics; Optic nerve head/parameter, structure; Tomography/method; Heidelberg retinal tomograph; Adult; Gender

Enhancing Mechanical Properties and Formability of AISI 301LN Stainless Steel Sheet by Local Laser Heat Treatment

This study demonstrates applying local laser heat treatment to produce ultrafine-grained austenite (UFGA) structures in an AISI 301LN type commercial austenitic steel. Pieces of 50% cold-rolled sheets containing more than 90% strain-induced martensite were heated locally by a laser beam to various peak temperatures to obtain different degrees of martensite reversion to austenite. Mechanical properties and formability of grain-refined and coarse-grained structures were measured by tensile and Erichsen cup tests. In addition to standard Erichsen cup test, additional interrupted tests were carried out, where cups were first stretched close to the critical strain. Drawn cups were then heated locally by a laser beam to revitalize the structure and thereby enhance the formability in the following cupping test until failure. Results showed that local laser heat treatment is suitable for the reversion treatment to refine the austenite grain size. Various structures were produced: completely reverted microstructures (T &gt; 700 °C) with grain sizes 0.9 - 2 µm in addition to partially reverted structure (T &lt; 700 °C) containing nano- and ultrafine-grained austenite (0.6 µm) with some martensite. The grain refinement by local annealing improved the strength properties. The Erichsen cup tests showed that the formability was equal in the completely reverted ultrafine-grained structures to that of the coarse-grained sheets. It was demonstrated that the local laser treatment restored formability of the drawn cups, allowing stretching to be continued. The second forming step after the laser-treatment provided an enhancement of 19 and 14% in the cup depths in coarse-grained and ultrafine-grained steels, respectively, even though the laser-treatment parameters were not optimized yet.

Numerical and experimental investigation of pulsating blankholder effect on drawing of cylindrical part of aluminum alloy in deep drawing process

In this study, the effect of a new pulsating blankholder system has been investigated on improving the formability of aluminum 1050 alloy. By using this system, during each pulsating cycle, first, the metal was easily flowed into the die through removing the blankholder force, and then the blankholder force applied by springs was employed to prevent excessive metal flow and wrinkling. Deep drawing of cylindrical cup was simulated by ABAQUS6.7 software. Cup depth, tearing, and thickness distribution of the experimental and numerical analyses were then compared. The results indicated that by using the pulsating blankholder system coupled with proper frequency and gap, the cup depth can be increased and thickness distribution can be improved. Further, good agreement was observed between simulation and experimental results.

Analysis of peripapillary retinal nerve fiber layer thickness and papillary parameters in different degrees of myopic eyes

Background Myopia is an important risk factor of glaucoma.Investigation of the characteristics of retinal nerve fiber layer thickness (RNFLT) and optical head morphology in myopia patients was helpful for differentiating myopic change and glaucomatous change in myopic eye.Objective This study was to investigate the peripapillary RNFLT and papillary parameters in different degrees of myopic eyes.Methods A 5-year case series study was retrospectively analyzed.Total 168 eyes of 168 myopic patients without visual field defect were recruited and divided into three age matched groups according to spherical equivalent (SE):low myopia group (SE:-0.25 ～-0.75 D) (57 eyes),moderate myopia group (SE:-3.0 ～-5.75 D) (57 eyes) and high myopia group (SE:-6.0～-12.0 D) (54 eyes).The RNFLT was measured with scanning laser polarmetry (GDxVCC) and papillary parameters measured with confocal scanning laser ophthalmoscope (HRT Ⅱ).Intergroup difference of parameters from GDxVCC and HRT Ⅱ were analyzed using one-way analysis of variance and SNK-q test.The correlations between spherical equivalent and RNFLT or papillary parameters was evaluated with multiple linear regression analysis.Results The global average,superior and inferior average,standard deviation,inter-eye symmetry of RNFLT were gradually reduced as the increase of SE with significant differences among the three groups (F=6.193,7.127,3.874,4.098,3.128,P ＜ 0.05).Global average,superior average,standard deviation,inter-eye symmetry of RNFLT were significantly lower in the high myopia group than those in the low myopia group (q =5.334,4.526,4.586,20.679,P＜0.05).An statistically significant reduce in inter-eye symmetry was seen between the high myopia group and the moderate myopia group (q =6.225,P＜0.05) as well as between the moderate myopia group and the low myopia group (q =10.035,P＜0.05).The multiple regression analysis showed that global average,superior average,inferior average,standard deviation,inter-eye symmetry of the R NFLT decreased with the increase of SE (β=0.441,t=6.329,P=0.000;β=0.471,t=6.880,P=0.000;β=0.339,t=4.641,P=0.000;β=0.389,t=5.445,P =0.000 ; β =0.338,t =4.621,P =0.000).Cup volume,linear cup/disk ratio,mean cup depth and maximum cup depth in the high myopia group were significantly lower than those of the moderate myopia groups (q =2.603,P =0.0l 1 ;q =2.105,P =0.037 ; q =2.825,P =0.006 ; q =2.495,P =0.014).Mean cup depth and height variation contour were significantly decreased in the high myopia group compared with the low myopia group (q =2.562,P =0.013 ;q =2.203,P =0.030).Rim area,rim volume,height variation contour were positively correlated with the degree of myopia (β=0.195,t=-2.565,P=0.011 ;β=0.199,t=-2.611,P=0.010;β=0.177,t =-2.311,P=0.022) ; while mean cup depth were negatively correlated with the degree of myopia (β =0.153,t =1.997,P =0.047).Conclusions As the increase of myopia degree,superior and inferior quadrants of RNFLT and cup depth are declined,but rim volume is elevated.Myopia is a confounding factor when RNFL data is interpreted by GDxVCC and papillary parameter by HRT Ⅱ. Key words: Biometry; Myopia; Retina nerve fiber layer thickness; Papillary contour

The Heidelberg retina tomograph ancillary study to the European glaucoma prevention study: study design and baseline factors

To describe the study design and baseline factors of the Heidelberg Retina Tomograph ancillary study within the EGPS. Furthermore, to examine the relationship between HRT optic disc topographic measurements and baseline demographic and ocular factors. Four hundred and eighty-nine ocular hypertensive participants were included. Each participant completed HRT imaging at least annually. The associations between HRT measurements and IOP, central corneal thickness (CCT), baseline photographic estimates of vertical CDR ratio (CDR), asymmetry between the two eyes in CDR ratio and baseline visual field indices were assessed using regression analysis. Associations between HRT measurements and vertical CDR by photographs were found for almost all stereometric optic disc parameters in both univariate and multivariate analysis. The strongest association was found between vertical CDR measurements and disc, cup and rim area; cup and rim volume, CDR area, linear CDR, mean and maximum cup depth and cup shape measure (all p < 0.0001). In multivariate analysis, pattern standard deviation (PSD) and HRT disc area had significant associations with several HRT optic disc measurements. Furthermore, CCT was significantly associated with reference height and the glaucoma probability score (GPS, outside normal limits). The EGPS is the first multicentre, placebo-controlled randomized clinical trial to use HRT for monitoring optic disc changes in participants with ocular hypertension. We found strong associations between stereophotographic vertical CDR estimates, HRT disc area, PSD and several HRT parameters. We found, furthermore, that the parameters reference height and GPS were significantly related to central corneal thickness.

Effects of culture media and stocking density on biofouling, shell shape, growth, and survival of the Pacific oyster (Crassostrea gigas) and the Manila clam (Venerupis philippinarum) in suspended culture

Suspended culture of bivalves offers a number of advantages over beach (intertidal) culture, but is often hindered by two issues: biofouling and suboptimal shell shape. This study assessed the efficacy of two novel culture media in Pacific oyster (Crassostrea gigas) grow-out and Manila clam (Venerupis philippinarum) nursery tray culture. We examined the combined effects of culture media type (expanded clay aggregate and lava rock), media volume (0, 15, 30, and 45Lm−2), and bivalve stocking density (226, 453, and 679indm−2 for oysters; 3019, 9057, and 15,094indm−2 for clams) on biofouling levels, shell characteristics, growth, condition, and survival of bivalves. Adding either media type to culture trays significantly reduced mussel fouling on oysters and effectively eliminated clam entanglement in mussel byssus. Clay aggregate was more effective at controlling tube worms and combined fouling on oysters than lava rock. Oyster shell shape index was not affected by either media type and decreased with increased stocking density. Oyster cup depth index decreased at higher media volumes and stocking densities, likely as a result of space restrictions. Reduced growth and condition were observed in both clams and oysters as media volume and stocking density increased. The presence of culture media slightly decreased oyster survival and improved clam survival. Oysters in all treatments exceeded minimum industry marketability standards. The benefits of culture media for biofouling control were realized at the lowest media volume (15Lm−2) suggesting that the efficacy of lower volumes of media should be assessed in the future.

Effect of surgery-lowing intraocular pressure on optic nerve head parameters and retinal nerve fiber layer thickness

Background Lowing intraocular pressure (IOP) is the only effective treating method in glaucoma.Making sure the change of optic disc parameters and retinal nerve fiber layer thickness(RNFLT) in primary open-angle glaucoma (POAG) patients after IOP reduced can provide objective evidence for evaluating the effect of lowing-IOP on the function of optic nerve.Objective The present study was to evaluate the change of optic disc parameters and RNFLT in POAG patients after trabeculectomy,and analyze the affecting factors of image parameters.Methods A serial case-observational study was adapted.Forty eyes of 39 patients with POAG underwent trabeculectomy were recruited in the study.IOP was examined and perimetry was performed before operation and 2 weeks,1 month,3 months,6 months and 1 year after surgery.Optical parameters and RNFLT were measured using Heidelberg retina tomography (HRT) and optical coherence tomography (OCT) in above-mentioned time points.The correlations between lowing-IOP range or disease severity and optical disc parameters or mean RNFLT (mRNFLT) were analyzed by Pearson linear correlation.Results Mean IOP of the 40 eyes was (32.77±8.64) mmHg before operation and (12.45 ±3.65) mmHg,(13.05±3.90) mmHg,(13.42± 3.33) mmHg,(14.22± 2.60) mmHg and (14.74±2.46)mmHg 2 weeks,1 month,3 months,6 months and 1 year after operation,with a significant difference among various time points (F=13.73,P =0.00).However,no significant difference was seen in the mean defect of perimetry among the different time points (F=1.02,P=0.41).The cup area (CA),cup/disc area ratio (C/DAR),cup volume (CV),mean cup depth (MCD),cup shape measurement (CSM),horizontal C/D,vertical C/D,rim area (RA),rim/disc area ratio (R/DAR),height variation contour (HVC),rim volume (RV),mRNFLT,RNFL cross sectional area (RNFLA) were gradually improved after operation in comparison with before operation.One year after operation,RV,CSM,mRNFLT,RNFLA were still increased,but vertical C/D was reduced after operation than that of before (P＜0.05).No significant differences were found in the whole mRNFLT and superior quadrant mRNFLT,inferior quadrant mRNFLT,nasal quadrant mRNFLT and temporal quadrant mRNFLT among before and after operation (F=1.63,P=0.16; F=0.51,P=0.77; F=1.44,P=0.20;F=1.02,P=0.32; F=1.31,P=0.30).Positive correlations were found between lowing-IOP range and the improvement of RV,CSM,vertical C/D (r =0.45,P =0.02; r=0.41,P=0.04; r=0.58,P=0.00),and negative correlations were seen between absolute value of MD and the improvement of RV,CSM 1 year after operation (r=-0.43,P=0.03; r=-0.62,P=0.00).Conclusions Reduction of IOP after trabeculectomy results in the reversal of optic disc parameters.The improvement of the optic disc parameters may be a protective factor for progression of glaucomatous optical nerve damage. Key words: Trabeculectomy; Glaucoma; Bio-measurement; Optic nerve head; Retinal nerve fiber layer

Optic nerve head morphology in young patients after antiglaucomatous filtering surgery

To compare the optic nerve head appearance in glaucomatous eyes before and after marked reduction of intraocular pressure (IOP). The hospital-based observational case-series study included selected glaucoma patients for whom optic disc photographs taken before and 1 week to 5 months after surgical reduction of IOP were morphometrically examined. The study included 23 eyes of 16 patients (mean age: 28.7 ± 6.0 years). Mean preoperative IOP was 31.6 ± 7.7 mmHg (22-52 mmHg), and mean IOP drop was 21.5 ± 8.4 mmHg (11-45 mmHg). The horizontal disc diameter decreased significantly (p < 0.001) after surgery, while the vertical disc diameter did not change markedly (p = 0.54). The width of the neuroretinal rim increased significantly in all disc quadrants (all p-values ≤ 0.01), optic cup depth decreased (p < 0.001), and reflectivity of the inner retinal surface increased significantly (p < 0.001). Some eyes showed a pronounced reduction in beta zone of parapapillary atrophy parallel to an increase in horizontal disc diameter, and some eyes showed an enlargement of beta zone parallel to a reduction in horizontal disc diameter. After marked reduction of high IOP, some eyes of young adult patients with glaucoma can show a horizontal shrinkage of the optic nerve head, in addition to a partial restoration of the neuroretinal rim and a flattening of the optic cup. In addition, beta zone of parapapillary atrophy can decrease or increase, complementarily to changes in the horizontal disc diameter. These findings may be of interest for the biomechanics of the optic nerve head and the precision of imaging techniques.

Symmetry of Optic Nerve Head Parameters Measured by the Heidelberg Retina Tomograph 3 in Healthy Eyes: The Blue Mountains Eye Study

To assess the symmetry of optic nerve head parameters measured by the Heidelberg Retina Tomograph 3 (HRT 3) between fellow eyes in a normal elderly population. Cross-sectional population-based study. Participants of the Blue Mountains Eye Study 10-year follow-up who did not have optic disc disease, including glaucoma, were included. Optic nerve head parameters measured by HRT 3 were compared between fellow eyes. The normal range of interocular asymmetry (larger disc minus smaller disc) was determined by the 2.5th and 97.5th percentiles. A total of 1276 eligible participants had HRT scans of both eyes. HRT measurements in right eyes differed slightly in rim steepness and rim volume from those in left eyes (P < .05). The 2.5th and 97.5th percentile of interocular asymmetry limits were -0.41 and 0.45 for cup-to-disc ratio and -0.19 and 0.22 for cup-to-disc area ratio, respectively. The highest interocular correlation was found in disc area and cup area (r ranged from 0.74-0.76), whereas mean cup depth, cup volume, and retinal nerve fiber layer thickness had the poorest correlation (r ≤ 0.07). Greater optic disc area asymmetry was associated with a larger interocular difference in the other optic nerve head parameters. There was minimal interocular difference and substantial interocular correlation in optic nerve head parameters measured by HRT 3. Interocular asymmetry greater than 0.2 for cup-to-disc area ratio was considered outside the normal range.

Effects of design parameters of total hip components on the impingement angle and determination of the preferred liner skirt shape with an adequate oscillation angle

The oscillation angle (OsA), which is the sum of the impingement angles on the two sides when the prosthetic neck sways from the neutral axis of the acetabular cup to the liner rim, is one of the most important factors that can affect the range of motion of an artificial hip joint. The aim of this study was to determine the influence of total hip component design on the impingement angle. Our findings show that an increase in cup depth of the liner restricts the motion of the neck and results in a reduced impingement angle, while an increase in chamfer angle increases the impingement angle until it reaches a critical value when a further increase no longer results in an increase in impingement angle. The impingement angle is not only dependent on the head/neck ratio, but also on the head size itself. For most arbitrarily chosen cup depths and chamfer angles, the neck only impacts at one point on the liner. This study proposes a suitable combination of cup depth and chamfer angle and a preferred impact mode, which, if impingement does occur, enables the neck to impinge on the liner rim over a large area. Cup-neck combinations that have an adequate OsA with maximum femoral head coverage are presented.

Association between corneal biomechanical properties and optic nerve head morphology in newly diagnosed glaucoma patients

To investigate the association between corneal biomechanics and optic nerve head morphology in newly diagnosed primary open-angle glaucoma patients. Hospital based prospective study. Forty-two untreated newly diagnosed primary open-angle glaucoma patients. Patients underwent corneal hysteresis measurement using the Ocular Response Analyzer and confocal scanning laser ophthalmoscopy for optic nerve head topography evaluation. One eye was selected randomly for analysis. Data collected included age, race, gender, intraocular pressure and central corneal thickness. Multiple regression analysis (controlling for baseline intraocular pressure and disc area) was used to investigate factors associated with the following optic nerve head topographic parameters: linear cup-to-disc ratio and mean cup depth. Mean age of participants was 66.7 ± 11.8 years. Corneal hysteresis was the only factor significantly associated with both mean cup depth (correlation coefficient [r] = -0.34, P = 0.03) and cup-to-disc ratio (r = -0.41, P = 0.01). Central corneal thickness was significantly associated with mean cup depth (r = -0.35, P = 0.02), but not with cup-to-disc ratio (r = -0.25, P = 0.13). Although a trend towards a positive association between age and cup-to-disc ratio was identified (r = 0.26, P = 0.08), age was not significantly associated with mean cup depth (r = 0.06, P = 0.72). When comparing fellow eyes of patients with bilateral glaucoma, the eye with higher corneal hysteresis had smaller cup-to-disc ratio in 75% of the cases. In untreated newly diagnosed primary open-angle glaucoma patients, those with thinner corneas and mainly lower corneal hysteresis values had a larger cup-to-disc ratio and deeper cup, independently of intraocular pressure values and disc size.

Comparison of Spectral-Domain Optical Coherence Tomography and Heidelberg Retina Tomograph III Optic Nerve Head Parameters in Glaucoma

Background: To evaluate the agreement between the optic nerve head (ONH) measurements obtained by spectral-domain optical coherence tomography/scanning laser ophthalmoscope (SD-OCT/SLO) and the Heidelberg retinal tomograph III (HRT-III), and to compare the ONH measurements of both devices in different glaucoma types. Methods: In a prospective study, 30 patients with primary open-angle glaucoma (POAG) and 30 patients with pseudoexfoliation glaucoma (PXG) were enrolled. All patients underwent SD-OCT/SLO and HRT-III evaluation of the ONH during the same visit. Agreement between measurements of SD-OCT/SLO and HRT-III were evaluated by determination of intraclass correlation coeficients. In addition, mean ONH measurements obtained with both devices were compared between POAG and PXG patient groups. Results: Mean SD-OCT/SLO measurements were greater than those of HRT-III, except for mean and maximum cup depth. Intraclass correlation coefficient values for disc area, rim area, cup area, cup/disc area ratio, mean cup depth and maximum cup depth were 0.367, 0.213, 0.632, 0.681, 0.775 and 0.661, respectively. No significant differences were found between ONH parameters of POAG and PXG patients as measured with both devices (p > 0.01). Conclusion: ONH measurements with SD-OCT/SLO and HRT-III did not show clinically acceptable agreement in glaucoma patients. This precludes interchangeable use of these measurements in clinical practice. PXG and POAG patient groups displayed similar ONH measurements with both devices.

Eggs in the Freezer: Energetic Consequences of Nest Site and Nest Design in Arctic Breeding Shorebirds

Birds construct nests for several reasons. For species that breed in the Arctic, the insulative properties of nests are very important. Incubation is costly there and due to an increasing surface to volume ratio, more so in smaller species. Small species are therefore more likely to place their nests in thermally favourable microhabitats and/or to invest more in nest insulation than large species. To test this hypothesis, we examined characteristics of nests of six Arctic breeding shorebird species. All species chose thermally favourable nesting sites in a higher proportion than expected on the basis of habitat availability. Site choice did not differ between species. Depth to frozen ground, measured near the nests, decreased in the course of the season at similar non-species-specific speeds, but this depth increased with species size. Nest cup depth and nest scrape depth (nest cup without the lining) were unrelated to body mass (we applied an exponent of 0.73, to account for metabolic activity of the differently sized species). Cup depth divided by diameter2 was used as a measure of nest cup shape. Small species had narrow and deep nests, while large species had wide shallow nests. The thickness of nest lining varied between 0.1 cm and 7.6 cm, and decreased significantly with body mass. We reconstruct the combined effect of different nest properties on the egg cooling coefficient using previously published quantitative relationships. The predicted effect of nest cup depth and lining depth on heat loss to the frozen ground did not correlate with body mass, but the sheltering effect of nest cup diameter against wind and the effects of lining material on the cooling coefficient increased with body mass. Our results suggest that small arctic shorebirds invest more in the insulation of their nests than large species.