Understanding of the biomechanics of the accommodative apparatus in the eyes with different refraction is important for solving the problems of theoretical and practical ophthalmology. Purpose: To determine the change...Understanding of the biomechanics of the accommodative apparatus in the eyes with different refraction is important for solving the problems of theoretical and practical ophthalmology. Purpose: To determine the changes of anterior eye segment dimensions during accommodation response in normal eyes and in patients with myopia, hypermetropia. Methods and Material: 116 eyes (56 patients aged from 18 to 30 years, refraction from -2.0 to + 2.0 D) were examined. All the patients underwent a full ophthalmological examination. The ocular anterior segment was imaged using a rotational Scheimpflug camera Pentacam HR (Oculus, Wetzlar, Germany) under non- and 3.0 D of accommodative demands. The statistical data were represented as the mean value ± standard deviation (M ± SD). The Shapiro-Wilk test was used to assess the normality distribution. Wilcoxon test was used for comparison. Results: Results showed an increase in the optical density of the crystalline lens, a pupil diameter decrease and changing of the iris profile during accommodation in all patients. An increase in the total corneal aberrations and decrease in the corneal spherical aberration were revealed only in emmetropic eyes. Conclusions: The accommodative response is a multicomponent process. Scheimpflug visualization revealed the differences in the accommodative response in normal and ametropic eyes.展开更多
AIM： To analyze the correlations between ocular biomechanical and biometric data of the eye,measured by Scheimpflug-based devices on healthy subjects.METHODS： Three consecutive measurements were carried out using th...AIM： To analyze the correlations between ocular biomechanical and biometric data of the eye,measured by Scheimpflug-based devices on healthy subjects.METHODS： Three consecutive measurements were carried out using the corneal visualization Scheimpflug technology（Cor Vis ST） device on healthy eyes and the 10 device-specific parameters were recorded.Pentacam HR-derived parameters（corneal curvature radii on the anterior and posterior surfaces;apical pachymetry;corneal volume;corneal aberration data;depth,volume and angle of the anterior chamber） and axial length（AL） from IOLMaster were correlated with the 10 specific CorV is ST parameters.RESULTS： Measurements were conducted in 43 eyes of 43 volunteers（age 61.24±15.72y）.The 10 specific Cor Vis ST data showed significant relationships with corneal curvature radii both on the anterior and posterior surface,pachymetric data,root mean square（RMS） data of lower-order aberrations,and posterior RMS of higher-order aberrations and spherical aberration of the posterior cornea.Anterior chamber depth showed a significant relationship,but there were no significant correlations between corneal volume,anterior chamber volume,mean chamber angle or AL and the 10 specific CorV is ST parameters.CONCLUSION： Cor Vis ST-generated parameters are influenced by corneal curvature radii,some corneal RMS data,but corneal volume,anterior chamber volume,chamber angle and AL have no correlation with the biomechan-ical parameters.The parameters measured by CorV is ST seem to refer mostly to corneal properties of the eye.展开更多
AIM: To compare the anterior segment measurements obtained by rotating Scheimpflug camera(Pentacam) and Scanning-slit topography(Orbscan IIz) in keratoconic eyes.METHODS: A total of 121 patients, 71 males(58.7%)and 50...AIM: To compare the anterior segment measurements obtained by rotating Scheimpflug camera(Pentacam) and Scanning-slit topography(Orbscan IIz) in keratoconic eyes.METHODS: A total of 121 patients, 71 males(58.7%)and 50 females(41.3%)(214 eyes) with the diagnosis of keratoconus(KC) were enrolled in this study. Following diagnosis of KC by slit-lamp biomicroscopic examination, central corneal thickness(CCT), thinnest corneal thickness(TCT), anterior chamber depth(ACD),and pupil diameter(PD) were measured by a single examiner using successive instrumentation by Pentacam and Orbscan.RESULTS: There was no significant difference between the two instruments for the measurement of CCT and TCT. In contrast, scanning-slit topography measured ACD(3.46±0.40 mm vs 3.38±0.33 mm, P =0.019) and PD(4.97 ±1.26 mm vs 4.08 ±1.19 mm, P 【0.001) significantly larger than rotating Scheimpflug camera.The two devices made similar measurements for CCT(95% CI:-2.94 to5.06, P =0.602). However, the mean difference for TCT was-6.28(95% CI:-10.51 to-2.06, P =0.004) showing a thinner measurement by Orbscan than by Pentacam. In terms of the ACD, the mean difference was 0.08 mm(95%CI: 0.04 to 0.12, P 【0.001) with Orbscan giving a slightly larger value than Pentacam. Similarly, Orbscan measurement for PD was longer than Pentacam(95% CI:0.68 to 1.08, P 【0.001).CONCLUSION: A good agreement was found between Pentacam and Orbscan concerning CCT measurement while comparing scanning-slit topography and rotatingScheimpflug camera there was an underestimation for TCT and overestimation for ACD and PD.展开更多
AIM：To evaluate corneal parameters measured with a dual Scheimpflug analyzer in keratoconus patients implanted with intrastromal corneal ring segments（ICRS）.METHODS：Fifty eyes of 40 keratoconus patients had Ferrar...AIM：To evaluate corneal parameters measured with a dual Scheimpflug analyzer in keratoconus patients implanted with intrastromal corneal ring segments（ICRS）.METHODS：Fifty eyes of 40 keratoconus patients had Ferrara ICRS implantation from November 2010 to April2014.Uncorrected visual acuity（UCVA）,best corrected visual acuity（BCVA）,refraction,keratometry,asphericity,elevation,pachymetry,root mean square（RMS）,spherical aberration and coma were studied.All patients were evaluated using a dual Scheimpflug system.RESULTS：The mean follow-up time after the procedure was 12.7mo.The mean UCVA improved from0.82 to 0.31（P〈0.001）;the mean BCVA improved from0.42 to 0.05（P〈0.0001）,the mean spherical refraction changed from-3.06 ±3.80 D to-0.80 ±2.5 D（P〈0.0001）and the mean refraction astigmatism reduced from-4.51 ±2.08 D to-2.26±1.18 D（P〈0.0001）.The changes from preoperative to postoperative,in parameters of the anterior and posterior surface of the cornea,were statistically significant except the elevation posterior at the apex of the cornea and posterior asphericity.CONCLUSION：The implantation of Ferrara ICRS induces changes in both anterior and posterior surfaces of the cornea.展开更多
AIM：To compare the repeatability/reproducibility of measurement by high-resolution Placido disk-based topography with that of a high-resolution rotating Scheimpflug camera and assess the agreement between the two ins...AIM：To compare the repeatability/reproducibility of measurement by high-resolution Placido disk-based topography with that of a high-resolution rotating Scheimpflug camera and assess the agreement between the two instruments in measuring corneal power in eyes with keratoconus and post-laser in situ keratomileusis（LASIK）. METHODS：One eye each of 36 keratoconic patients and 20 subjects who had undergone LASIK was included in this prospective observational study. Two independent examiners worked in a random order to take three measurements of each eye with both instruments. Four parameters were measured on the anterior cornea：steep keratometry（Ks）,flat keratometry（Kf）,mean keratometry（Km）,and astigmatism（Ks-Kf）. Intra-examiner repeatability and inter-examiner reproducibility were evaluated by calculating the within-subject standard deviation（Sw）the coefficient of repeatability（R）,the coefficient of variation（Co V）,and the intraclass correlation coefficient（ICC）. Agreement between instruments was tested with the BlandAltman method by calculating the 95% limits of agreement（95% Lo A）.RESULTS：In keratoconic eyes,the intra-examiner and inter-examiner ICC were 〉0.95. As compared with measurement by high-resolution Placido disk-based topography,the intra-examiner R of the high-resolution rotating Scheimpflug camera was lower for Kf（0.32 vs 0.88）,Ks（0.61 vs 0.88）,and Km（0.32 vs 0.84）but higher for Ks-Kf（0.70 vs 0.57）. Inter-examiner R values were lower for all parameters measured using the high-resolution rotating Scheimpflug camera. The 95% Lo A were-1.28 to ＋0.55 for Kf,-1.36 to ＋0.99 for Ks,-1.08 to ＋0.50 for Km,and-1.11 to ＋1.48 for Ks-Kf. In the post-LASIK eyes,the intra-examiner andinter-examiner ICC were 〉0.87 for all parameters. The intra-examiner and inter-examiner R were lower for all parameters measured using the high-resolution rotating Scheimpflug camera. The intra-examiner R was 0.17 vs 0.88 for Kf,0.21 vs 0.88 for Ks,0.17 vs 0.86 for Km,and 0.28 vs 0.33 for Ks-Kf. The inter-examiner R was 0.09 vs 0.64 for Kf,0.15 vs 0.56 for Ks,0.09 vs 0.59 for Km,and 0.18 vs 0.23 for Ks-Kf. The 95% Lo A were-0.54 to ＋0.58 for Kf,-0.51 to ＋0.53 for Ks and Km,and-0.28 to ＋0.27 for Ks-Kf. CONCLUSION：As compared with Placido disk-based topography,the high-resolution rotating Scheimpflug camera provides more repeatable and reproducible measurements of Ks,Kf and Ks in keratoconic and post-LASIK eyes. Agreement between instruments is fair in keratoconus and very good in post-LASIK eyes.展开更多
AIMTo measure central corneal thickness (CCT) and pre-corneal tear film thickness using the Galilei dual-Scheimpflug analyzer (GSA) in New Zealand white rabbits.
AIM： To assess central corneal thickness （CCT） changes measured with Scheimpflug device following instillation of 2% fluorescein in normal subjects. ~ METHODS： This was a prospective randomized study of 60 hospita...AIM： To assess central corneal thickness （CCT） changes measured with Scheimpflug device following instillation of 2% fluorescein in normal subjects. ~ METHODS： This was a prospective randomized study of 60 hospital volunteers. After baseline CCT measurements of both eyes of 40 subjects were obtained using Scheimpflug system, a drop of preservative-free 2% fluorescein, was instilled in one eye and in other eye, one drop of normal saline （control）. Measurements were repeated after 1, 2, 5, 10, 20, 30, 40, 50 and 60min （continuous assessment group）. Twenty subjects had baseline CCT taken, then fluorescein was instilled in one eye and measurements were taken at lmin. Ten eyes had saline rinse after lmin and 10 other eyes did not, measurements were repeated at 2min （eye rinse group）. RESULTS： The mean baseline CCT for continuous assessment group was 546.2±32.1um （range, 489.0-606.0）, control eyes was 546.6~±30.7 um （range, 489.0-602.0）. At lmin after fluorescein instillation, CCT significantly increased by 37.0±34.0um （P〈0.001）, then decreased gradually, reaching baseline at 60min. CCT variations were not significant in control group （P〉0.05）. For eye rinse group, CCT mean differences between baseline and 2min were 18.2um （95 % Ch -54.7 to 18.3） with rinse and 26.5um （95% CI： -62.9 to 9.9） without rinse; paired sample tests were not significant （P〉0.05）. CONCLUSION： The presence of fluorescein increased CCT value to a clinically relevant level of 6.8%. Eye rinse did not significantly reduce the effect at 2min post fluorescein timepoint.展开更多
AIM:To evaluate the clinical use of Fourier analysis of videokeratography data in the diagnosis and follow-up of keratoconus(KC).METHODS:We conducted a chart review of consecutive patients presented to our cornea clin...AIM:To evaluate the clinical use of Fourier analysis of videokeratography data in the diagnosis and follow-up of keratoconus(KC).METHODS:We conducted a chart review of consecutive patients presented to our cornea clinic.A team of two experienced cornea specialists divided the patients into three groups:normal cornea,forme fruste KC(FFKC),and clinical KC.The exclusion criteria were a history of previous ocular surgery,any accompanying corneal pathology other than KC,high myopia(>6.00 diopters),amblyopia,pregnancy,breastfeeding,or any current autoimmune disease.The data of Fourier series harmonic analysis were evaluated for their diagnostic capacity using the receiver operating characteristic(ROC)curve.A binary logistic regression analysis was also conducted to construct a diagnostic model.A total of 259 eyes showed progression in the clinical KC group and underwent a combination of accelerated corneal collagen cross-linking and topographyguided customized treatment with an excimer laser.RESULTS:The study included 1262 eyes(618 normal,530 KC,and 114 FFKC)of 1262 patients.We observed that maximum decentration(MaxDec)was almost as good as maximum keratometry(Kmax)in detecting progressive KC.The area under the curve(AUC)was 0.95 for KC[95%confidence interval(CI):0.93-0.96]and 0.84 for FFKC(95%CI:0.79-0.88).Higher predictive accuracy was obtained using a model combining the spherical component,MaxDec,irregularity,and regular astigmatism in the center of the cornea(AUC:0.97;sensitivity:89%,and specificity:96%).CONCLUSION:Decentration,Kmax,and posterior radii of curvatures from a 3.0-mm optical zone centered on the thinnest point of the cornea provide the highest accuracy with low reproducibility of Kmax.展开更多
AIM:To explore the possibility of deploying three contactless devices(static and rotating Scheimpflug technology,spectral domain optical coherence tomography)for measuring central corneal thickness(CCT)in preoperative...AIM:To explore the possibility of deploying three contactless devices(static and rotating Scheimpflug technology,spectral domain optical coherence tomography)for measuring central corneal thickness(CCT)in preoperative and postoperative examinations of cataract patients.METHODS:Totally 72 patients who had undergone surgery without complications were selected.The CCT was measured prior to the operation,as well as on the first,5th-7th and 28th day following the operation using the Nidek NT 530-P,Sirius?,and Topcon OCT-2000 devices.RESULTS:A significant postoperative increase and subsequent decrease in CCT was identified with all three devices.The correlations were highly significant and thus reflect a very good degree of comparability at all times with the exception of the rotating Scheimpflug camera.The postoperative results from the latter differed significantly from the other devices.The correlations were Sirius/Topcon(P=0.010)and Sirius/Nidek(P<0.0005).No statistically significant difference could be identified in the comparison between Topcon and Nidek(P=0.056).CONCLUSION:All three devices are suitable for postoperative monitoring of CCT.The measurement results are only comparable to a limited extent and not interchangeable in the course of treating a single patient.This is due to the different imaging technology used in the devices and the resulting modalities for conducting the measurements.展开更多
To examine postoperative positional stability of myopic phakic intraocular len ses (IOLs). Prospective, nonrandomized clinical study. The study included 46 eye s which received an anterior chamber angle supported (Bau...To examine postoperative positional stability of myopic phakic intraocular len ses (IOLs). Prospective, nonrandomized clinical study. The study included 46 eye s which received an anterior chamber angle supported (Bausch &Lomb NuVita; 10 eyes) , anterior chamber iris fixated (Ophtec Artisan; 20 eyes) or ciliary sulc us implanted phakic IOL (Staar ICL; 16 eyes). The distance between the phakic I OL and the crystalline lens and the cornea as well as rotation around the optica l axis was evaluated using Scheimpflug photography at 1, 3 to 6, and 12 months p ostsurgery. The anterior chamber phakic IOLs showed no significant movement in a nteroposterior direction. The posterior chamber phakic IOL showed a significant movement toward the crystalline lens between postoperative months 3 and 12. The median amount of rotation around the optical axis between the 3 and the 12 mon th evaluation was 1.9 degrees (range= 0.0-33.5 degrees) for the NuVita, 0.6 deg rees (range=0.0 3.5 degrees) for the Artisan, and 0.9 degrees (range=0.2-2.3 d egrees) for the ICL. Four NuVita IOLs rotated more than 10 degrees. The angle s upported anterior chamber phakic IOLs showed a generally stable position regardi ng distance to cornea and natural lens, but rotation was observed in four IOLs. The iris fixated phakic IOL showed the highest overall stability. The posterior chamber phakic IOL was stable in terms of rotation but had a tendency to decrea se in distance toward the crystalline lens. Intraocular lenses implanted in phak ic eyes followed for 12 months demonstrate stable IOL position overall.展开更多
Background:We compared the human lens documented,using the Scheimpflug densitometry,with the light microscopic changes in the epithelium of the anterior central lens in patients with age-related cataract and diabetes ...Background:We compared the human lens documented,using the Scheimpflug densitometry,with the light microscopic changes in the epithelium of the anterior central lens in patients with age-related cataract and diabetes mellitus type II and verified the findings on the control tissue of the clear eye lens.We wanted to determine the relevance of the lens epithelium in cataract formation in type II diabetics compared to non-diabetics.Materials and methods:One hundred fifty central lens capsules(138 cataract and 12 clear lenses)of type II diabetics(n=77,45 female,32 male)and non-diabetics(n=73,41 female,32 male)were examined by light microscope,regarding defined histomorphological parameters.Further criteria were duration of diabetes,diabetic retinopathy,cataract(PENTACAM,scheimpflug densitometric definition),protein content in the aqueous humour(laser flare meter 500 KOWA,tyndallometry),different blood parameters and glucose content in the aqueous humour.Results:The mean cell density in the cataractous lens in type II diabetics was 3,951± 528 cells/mm2 and in nondiabetics 4,329± 580 cells/mm2(P< 0.001);in the clear lens it corresponded to 4,593± 409 cells/mm2(type II diabetics)and 4,894± 333 cells/mm2(non-diabetics,P=0.207).The cell density of the cataractous lens in type II diabetics(P=0.005)and in non-diabetics(P=0.035)is smaller than that of the clear lens.The cell area of the lens epithelium in the cataractous diabetic lens is larger(P< 0.001)and the nucleus-plasma ratio is lower(P< 0.001)than those of the clear non-diabetic lens.The increase in damage of the lens epithelium correlates with the decrease of cell density(P< 0.001),the increase of nucleus area and volume(P< 0.001),and the decrease of nucleus-plasma ratio(P< 0.001).Risk factors for the decrease of cell density are advanced age(P=0.015),type II diabetes(P=0.01),increase in glucose content in the aqueous humour(P=0.014),increase in blood sugar(P=0.003)and increase in glycosylated haemoglobin(P=0.039).Conclusions:The lens epithelium is primarily damaged in type II diabetics who develop age-related cataract.This might play an important role in cataract formation.展开更多
文摘Understanding of the biomechanics of the accommodative apparatus in the eyes with different refraction is important for solving the problems of theoretical and practical ophthalmology. Purpose: To determine the changes of anterior eye segment dimensions during accommodation response in normal eyes and in patients with myopia, hypermetropia. Methods and Material: 116 eyes (56 patients aged from 18 to 30 years, refraction from -2.0 to + 2.0 D) were examined. All the patients underwent a full ophthalmological examination. The ocular anterior segment was imaged using a rotational Scheimpflug camera Pentacam HR (Oculus, Wetzlar, Germany) under non- and 3.0 D of accommodative demands. The statistical data were represented as the mean value ± standard deviation (M ± SD). The Shapiro-Wilk test was used to assess the normality distribution. Wilcoxon test was used for comparison. Results: Results showed an increase in the optical density of the crystalline lens, a pupil diameter decrease and changing of the iris profile during accommodation in all patients. An increase in the total corneal aberrations and decrease in the corneal spherical aberration were revealed only in emmetropic eyes. Conclusions: The accommodative response is a multicomponent process. Scheimpflug visualization revealed the differences in the accommodative response in normal and ametropic eyes.
文摘AIM： To analyze the correlations between ocular biomechanical and biometric data of the eye,measured by Scheimpflug-based devices on healthy subjects.METHODS： Three consecutive measurements were carried out using the corneal visualization Scheimpflug technology（Cor Vis ST） device on healthy eyes and the 10 device-specific parameters were recorded.Pentacam HR-derived parameters（corneal curvature radii on the anterior and posterior surfaces;apical pachymetry;corneal volume;corneal aberration data;depth,volume and angle of the anterior chamber） and axial length（AL） from IOLMaster were correlated with the 10 specific CorV is ST parameters.RESULTS： Measurements were conducted in 43 eyes of 43 volunteers（age 61.24±15.72y）.The 10 specific Cor Vis ST data showed significant relationships with corneal curvature radii both on the anterior and posterior surface,pachymetric data,root mean square（RMS） data of lower-order aberrations,and posterior RMS of higher-order aberrations and spherical aberration of the posterior cornea.Anterior chamber depth showed a significant relationship,but there were no significant correlations between corneal volume,anterior chamber volume,mean chamber angle or AL and the 10 specific CorV is ST parameters.CONCLUSION： Cor Vis ST-generated parameters are influenced by corneal curvature radii,some corneal RMS data,but corneal volume,anterior chamber volume,chamber angle and AL have no correlation with the biomechan-ical parameters.The parameters measured by CorV is ST seem to refer mostly to corneal properties of the eye.
文摘AIM: To compare the anterior segment measurements obtained by rotating Scheimpflug camera(Pentacam) and Scanning-slit topography(Orbscan IIz) in keratoconic eyes.METHODS: A total of 121 patients, 71 males(58.7%)and 50 females(41.3%)(214 eyes) with the diagnosis of keratoconus(KC) were enrolled in this study. Following diagnosis of KC by slit-lamp biomicroscopic examination, central corneal thickness(CCT), thinnest corneal thickness(TCT), anterior chamber depth(ACD),and pupil diameter(PD) were measured by a single examiner using successive instrumentation by Pentacam and Orbscan.RESULTS: There was no significant difference between the two instruments for the measurement of CCT and TCT. In contrast, scanning-slit topography measured ACD(3.46±0.40 mm vs 3.38±0.33 mm, P =0.019) and PD(4.97 ±1.26 mm vs 4.08 ±1.19 mm, P 【0.001) significantly larger than rotating Scheimpflug camera.The two devices made similar measurements for CCT(95% CI:-2.94 to5.06, P =0.602). However, the mean difference for TCT was-6.28(95% CI:-10.51 to-2.06, P =0.004) showing a thinner measurement by Orbscan than by Pentacam. In terms of the ACD, the mean difference was 0.08 mm(95%CI: 0.04 to 0.12, P 【0.001) with Orbscan giving a slightly larger value than Pentacam. Similarly, Orbscan measurement for PD was longer than Pentacam(95% CI:0.68 to 1.08, P 【0.001).CONCLUSION: A good agreement was found between Pentacam and Orbscan concerning CCT measurement while comparing scanning-slit topography and rotatingScheimpflug camera there was an underestimation for TCT and overestimation for ACD and PD.
文摘AIM：To evaluate corneal parameters measured with a dual Scheimpflug analyzer in keratoconus patients implanted with intrastromal corneal ring segments（ICRS）.METHODS：Fifty eyes of 40 keratoconus patients had Ferrara ICRS implantation from November 2010 to April2014.Uncorrected visual acuity（UCVA）,best corrected visual acuity（BCVA）,refraction,keratometry,asphericity,elevation,pachymetry,root mean square（RMS）,spherical aberration and coma were studied.All patients were evaluated using a dual Scheimpflug system.RESULTS：The mean follow-up time after the procedure was 12.7mo.The mean UCVA improved from0.82 to 0.31（P〈0.001）;the mean BCVA improved from0.42 to 0.05（P〈0.0001）,the mean spherical refraction changed from-3.06 ±3.80 D to-0.80 ±2.5 D（P〈0.0001）and the mean refraction astigmatism reduced from-4.51 ±2.08 D to-2.26±1.18 D（P〈0.0001）.The changes from preoperative to postoperative,in parameters of the anterior and posterior surface of the cornea,were statistically significant except the elevation posterior at the apex of the cornea and posterior asphericity.CONCLUSION：The implantation of Ferrara ICRS induces changes in both anterior and posterior surfaces of the cornea.
文摘AIM：To compare the repeatability/reproducibility of measurement by high-resolution Placido disk-based topography with that of a high-resolution rotating Scheimpflug camera and assess the agreement between the two instruments in measuring corneal power in eyes with keratoconus and post-laser in situ keratomileusis（LASIK）. METHODS：One eye each of 36 keratoconic patients and 20 subjects who had undergone LASIK was included in this prospective observational study. Two independent examiners worked in a random order to take three measurements of each eye with both instruments. Four parameters were measured on the anterior cornea：steep keratometry（Ks）,flat keratometry（Kf）,mean keratometry（Km）,and astigmatism（Ks-Kf）. Intra-examiner repeatability and inter-examiner reproducibility were evaluated by calculating the within-subject standard deviation（Sw）the coefficient of repeatability（R）,the coefficient of variation（Co V）,and the intraclass correlation coefficient（ICC）. Agreement between instruments was tested with the BlandAltman method by calculating the 95% limits of agreement（95% Lo A）.RESULTS：In keratoconic eyes,the intra-examiner and inter-examiner ICC were 〉0.95. As compared with measurement by high-resolution Placido disk-based topography,the intra-examiner R of the high-resolution rotating Scheimpflug camera was lower for Kf（0.32 vs 0.88）,Ks（0.61 vs 0.88）,and Km（0.32 vs 0.84）but higher for Ks-Kf（0.70 vs 0.57）. Inter-examiner R values were lower for all parameters measured using the high-resolution rotating Scheimpflug camera. The 95% Lo A were-1.28 to ＋0.55 for Kf,-1.36 to ＋0.99 for Ks,-1.08 to ＋0.50 for Km,and-1.11 to ＋1.48 for Ks-Kf. In the post-LASIK eyes,the intra-examiner andinter-examiner ICC were 〉0.87 for all parameters. The intra-examiner and inter-examiner R were lower for all parameters measured using the high-resolution rotating Scheimpflug camera. The intra-examiner R was 0.17 vs 0.88 for Kf,0.21 vs 0.88 for Ks,0.17 vs 0.86 for Km,and 0.28 vs 0.33 for Ks-Kf. The inter-examiner R was 0.09 vs 0.64 for Kf,0.15 vs 0.56 for Ks,0.09 vs 0.59 for Km,and 0.18 vs 0.23 for Ks-Kf. The 95% Lo A were-0.54 to ＋0.58 for Kf,-0.51 to ＋0.53 for Ks and Km,and-0.28 to ＋0.27 for Ks-Kf. CONCLUSION：As compared with Placido disk-based topography,the high-resolution rotating Scheimpflug camera provides more repeatable and reproducible measurements of Ks,Kf and Ks in keratoconic and post-LASIK eyes. Agreement between instruments is fair in keratoconus and very good in post-LASIK eyes.
文摘AIMTo measure central corneal thickness (CCT) and pre-corneal tear film thickness using the Galilei dual-Scheimpflug analyzer (GSA) in New Zealand white rabbits.
基金Supported by Research Centre, College of Applied Medical Sciencesthe Deanship of Scientific Research at King Saud University
文摘AIM： To assess central corneal thickness （CCT） changes measured with Scheimpflug device following instillation of 2% fluorescein in normal subjects. ~ METHODS： This was a prospective randomized study of 60 hospital volunteers. After baseline CCT measurements of both eyes of 40 subjects were obtained using Scheimpflug system, a drop of preservative-free 2% fluorescein, was instilled in one eye and in other eye, one drop of normal saline （control）. Measurements were repeated after 1, 2, 5, 10, 20, 30, 40, 50 and 60min （continuous assessment group）. Twenty subjects had baseline CCT taken, then fluorescein was instilled in one eye and measurements were taken at lmin. Ten eyes had saline rinse after lmin and 10 other eyes did not, measurements were repeated at 2min （eye rinse group）. RESULTS： The mean baseline CCT for continuous assessment group was 546.2±32.1um （range, 489.0-606.0）, control eyes was 546.6~±30.7 um （range, 489.0-602.0）. At lmin after fluorescein instillation, CCT significantly increased by 37.0±34.0um （P〈0.001）, then decreased gradually, reaching baseline at 60min. CCT variations were not significant in control group （P〉0.05）. For eye rinse group, CCT mean differences between baseline and 2min were 18.2um （95 % Ch -54.7 to 18.3） with rinse and 26.5um （95% CI： -62.9 to 9.9） without rinse; paired sample tests were not significant （P〉0.05）. CONCLUSION： The presence of fluorescein increased CCT value to a clinically relevant level of 6.8%. Eye rinse did not significantly reduce the effect at 2min post fluorescein timepoint.
文摘AIM:To evaluate the clinical use of Fourier analysis of videokeratography data in the diagnosis and follow-up of keratoconus(KC).METHODS:We conducted a chart review of consecutive patients presented to our cornea clinic.A team of two experienced cornea specialists divided the patients into three groups:normal cornea,forme fruste KC(FFKC),and clinical KC.The exclusion criteria were a history of previous ocular surgery,any accompanying corneal pathology other than KC,high myopia(>6.00 diopters),amblyopia,pregnancy,breastfeeding,or any current autoimmune disease.The data of Fourier series harmonic analysis were evaluated for their diagnostic capacity using the receiver operating characteristic(ROC)curve.A binary logistic regression analysis was also conducted to construct a diagnostic model.A total of 259 eyes showed progression in the clinical KC group and underwent a combination of accelerated corneal collagen cross-linking and topographyguided customized treatment with an excimer laser.RESULTS:The study included 1262 eyes(618 normal,530 KC,and 114 FFKC)of 1262 patients.We observed that maximum decentration(MaxDec)was almost as good as maximum keratometry(Kmax)in detecting progressive KC.The area under the curve(AUC)was 0.95 for KC[95%confidence interval(CI):0.93-0.96]and 0.84 for FFKC(95%CI:0.79-0.88).Higher predictive accuracy was obtained using a model combining the spherical component,MaxDec,irregularity,and regular astigmatism in the center of the cornea(AUC:0.97;sensitivity:89%,and specificity:96%).CONCLUSION:Decentration,Kmax,and posterior radii of curvatures from a 3.0-mm optical zone centered on the thinnest point of the cornea provide the highest accuracy with low reproducibility of Kmax.
文摘AIM:To explore the possibility of deploying three contactless devices(static and rotating Scheimpflug technology,spectral domain optical coherence tomography)for measuring central corneal thickness(CCT)in preoperative and postoperative examinations of cataract patients.METHODS:Totally 72 patients who had undergone surgery without complications were selected.The CCT was measured prior to the operation,as well as on the first,5th-7th and 28th day following the operation using the Nidek NT 530-P,Sirius?,and Topcon OCT-2000 devices.RESULTS:A significant postoperative increase and subsequent decrease in CCT was identified with all three devices.The correlations were highly significant and thus reflect a very good degree of comparability at all times with the exception of the rotating Scheimpflug camera.The postoperative results from the latter differed significantly from the other devices.The correlations were Sirius/Topcon(P=0.010)and Sirius/Nidek(P<0.0005).No statistically significant difference could be identified in the comparison between Topcon and Nidek(P=0.056).CONCLUSION:All three devices are suitable for postoperative monitoring of CCT.The measurement results are only comparable to a limited extent and not interchangeable in the course of treating a single patient.This is due to the different imaging technology used in the devices and the resulting modalities for conducting the measurements.
文摘To examine postoperative positional stability of myopic phakic intraocular len ses (IOLs). Prospective, nonrandomized clinical study. The study included 46 eye s which received an anterior chamber angle supported (Bausch &Lomb NuVita; 10 eyes) , anterior chamber iris fixated (Ophtec Artisan; 20 eyes) or ciliary sulc us implanted phakic IOL (Staar ICL; 16 eyes). The distance between the phakic I OL and the crystalline lens and the cornea as well as rotation around the optica l axis was evaluated using Scheimpflug photography at 1, 3 to 6, and 12 months p ostsurgery. The anterior chamber phakic IOLs showed no significant movement in a nteroposterior direction. The posterior chamber phakic IOL showed a significant movement toward the crystalline lens between postoperative months 3 and 12. The median amount of rotation around the optical axis between the 3 and the 12 mon th evaluation was 1.9 degrees (range= 0.0-33.5 degrees) for the NuVita, 0.6 deg rees (range=0.0 3.5 degrees) for the Artisan, and 0.9 degrees (range=0.2-2.3 d egrees) for the ICL. Four NuVita IOLs rotated more than 10 degrees. The angle s upported anterior chamber phakic IOLs showed a generally stable position regardi ng distance to cornea and natural lens, but rotation was observed in four IOLs. The iris fixated phakic IOL showed the highest overall stability. The posterior chamber phakic IOL was stable in terms of rotation but had a tendency to decrea se in distance toward the crystalline lens. Intraocular lenses implanted in phak ic eyes followed for 12 months demonstrate stable IOL position overall.
文摘Background:We compared the human lens documented,using the Scheimpflug densitometry,with the light microscopic changes in the epithelium of the anterior central lens in patients with age-related cataract and diabetes mellitus type II and verified the findings on the control tissue of the clear eye lens.We wanted to determine the relevance of the lens epithelium in cataract formation in type II diabetics compared to non-diabetics.Materials and methods:One hundred fifty central lens capsules(138 cataract and 12 clear lenses)of type II diabetics(n=77,45 female,32 male)and non-diabetics(n=73,41 female,32 male)were examined by light microscope,regarding defined histomorphological parameters.Further criteria were duration of diabetes,diabetic retinopathy,cataract(PENTACAM,scheimpflug densitometric definition),protein content in the aqueous humour(laser flare meter 500 KOWA,tyndallometry),different blood parameters and glucose content in the aqueous humour.Results:The mean cell density in the cataractous lens in type II diabetics was 3,951± 528 cells/mm2 and in nondiabetics 4,329± 580 cells/mm2(P< 0.001);in the clear lens it corresponded to 4,593± 409 cells/mm2(type II diabetics)and 4,894± 333 cells/mm2(non-diabetics,P=0.207).The cell density of the cataractous lens in type II diabetics(P=0.005)and in non-diabetics(P=0.035)is smaller than that of the clear lens.The cell area of the lens epithelium in the cataractous diabetic lens is larger(P< 0.001)and the nucleus-plasma ratio is lower(P< 0.001)than those of the clear non-diabetic lens.The increase in damage of the lens epithelium correlates with the decrease of cell density(P< 0.001),the increase of nucleus area and volume(P< 0.001),and the decrease of nucleus-plasma ratio(P< 0.001).Risk factors for the decrease of cell density are advanced age(P=0.015),type II diabetes(P=0.01),increase in glucose content in the aqueous humour(P=0.014),increase in blood sugar(P=0.003)and increase in glycosylated haemoglobin(P=0.039).Conclusions:The lens epithelium is primarily damaged in type II diabetics who develop age-related cataract.This might play an important role in cataract formation.
