摘要 :
PURPOSE: To measure the upper and lower tear menisci in patients with aqueous tear deficiency (ATD) dry eye by real-time optical coherence tomography (OCT) and to determine the most effective meniscus variables for the diagnosis o...
展开
PURPOSE: To measure the upper and lower tear menisci in patients with aqueous tear deficiency (ATD) dry eye by real-time optical coherence tomography (OCT) and to determine the most effective meniscus variables for the diagnosis of dry eye. METHODS: Eyes of 48 pre-screened ATD patients were compared with those of 47 healthy subjects. Upper and lower tear menisci were imaged simultaneously by real-time OCT immediately after blinking. The height, radius, and cross-sectional area of upper and lower tear menisci were obtained. RESULTS: The tear meniscus radius, height, and cross-sectional area were significantly smaller in patients with dry eye than in healthy subjects (P < 0.01). The lower tear meniscus variables were higher than the upper menisci (P < 0.01) in normal subjects; however, no significant differences between menisci were found in ATD patients. In both groups, the upper and lower tear meniscus variables were strongly correlated with each other. Good dry eye diagnostic accuracies were obtained with cutoff values for an abnormal lower tear meniscus radius (LTMR) of 182 microm and a lower tear meniscus height (LTMH) of 164 microm. The LTMR diagnostic sensitivity and specificity were 0.92 and 0.87, respectively. The LTMH diagnostic sensitivity and specificity were 0.92 and 0.90. CONCLUSIONS: Upper tear meniscus variables in ATD patients were assessed by real-time OCT. The tear meniscus was smaller in ATD patients than in healthy subjects. LTMR and LTMH may have potential in the diagnosis of ATD.
收起
摘要 :
PURPOSE: To measure the upper and lower tear menisci in patients with aqueous tear deficiency (ATD) dry eye by real-time optical coherence tomography (OCT) and to determine the most effective meniscus variables for the diagnosis o...
展开
PURPOSE: To measure the upper and lower tear menisci in patients with aqueous tear deficiency (ATD) dry eye by real-time optical coherence tomography (OCT) and to determine the most effective meniscus variables for the diagnosis of dry eye. METHODS: Eyes of 48 pre-screened ATD patients were compared with those of 47 healthy subjects. Upper and lower tear menisci were imaged simultaneously by real-time OCT immediately after blinking. The height, radius, and cross-sectional area of upper and lower tear menisci were obtained. RESULTS: The tear meniscus radius, height, and cross-sectional area were significantly smaller in patients with dry eye than in healthy subjects (P < 0.01). The lower tear meniscus variables were higher than the upper menisci (P < 0.01) in normal subjects; however, no significant differences between menisci were found in ATD patients. In both groups, the upper and lower tear meniscus variables were strongly correlated with each other. Good dry eye diagnostic accuracies were obtained with cutoff values for an abnormal lower tear meniscus radius (LTMR) of 182 microm and a lower tear meniscus height (LTMH) of 164 microm. The LTMR diagnostic sensitivity and specificity were 0.92 and 0.87, respectively. The LTMH diagnostic sensitivity and specificity were 0.92 and 0.90. CONCLUSIONS: Upper tear meniscus variables in ATD patients were assessed by real-time OCT. The tear meniscus was smaller in ATD patients than in healthy subjects. LTMR and LTMH may have potential in the diagnosis of ATD.
收起
摘要 :
Purpose. To investigate the effect of intraocular pressure (IOP) on wavefront aberrations in the anterior cornea, the internal optics, and the whole eye for myopic patients undergoing laser-assisted in situ keratomileusis (LASIK) ...
展开
Purpose. To investigate the effect of intraocular pressure (IOP) on wavefront aberrations in the anterior cornea, the internal optics, and the whole eye for myopic patients undergoing laser-assisted in situ keratomileusis (LASIK) surgery. Methods. Fifty-seven myopic subjects were tested for wavefront aberrations in the anterior corneal surface and the whole eye using a corneal topographer and a wavefront analyzer, respectively, pre and post-LASIK. The IOP and central corneal thickness (CCT) were measured with a noncontact tonometer and a pachymeter, respectively. Pre and postoperative wavefront aberrations were compared, and the correlation between changes in the Zernike aberrations and the IOP was statistically tested. Results. The mean root mean square (RMS) values of the higher-order aberrations (HOAs) were significantly increased in the anterior cornea, the internal optics, and the whole eye. The mean RMS values for a majority of Zernike terms were significantly increased, and systematic increases in the spherical aberrations were found in both the cornea and the whole eye. The spherical aberrations after LASIK were significantly correlated to the IOP (r = 0.59, P < 0.01, for oculus dexter [OD, right eye] and r = 0.49, P < 0.01, for oculus sinister [OS, left eye] in the cornea; r = 0.38, P < 0.01, for OD and r = 0.46, P < 0.01, for OS in the whole eye). Conclusions. IOP contributes to LASIK-induced HOAs, particularly spherical aberrations. To control the HOAs after LASIK, a new algorithm should include the IOP as a variable for laser surgery.
收起
摘要 :
Background: The objective of this study was to evaluate the retinal nerve fibre layer thickness (RNFLT) and retinal macular thickness (RMT) in esotropic amblyopic children. Methods: Twenty-one children diagnosed with esotropic amb...
展开
Background: The objective of this study was to evaluate the retinal nerve fibre layer thickness (RNFLT) and retinal macular thickness (RMT) in esotropic amblyopic children. Methods: Twenty-one children diagnosed with esotropic amblyopia at Strabismus and Amblyopia Department of Wenzhou Medical College Affiliated Eye Hospital, China, were enrolled in the study. Their fellow eyes were normal and were used as controls. RNFLT and RMT were measured by optical coherence tomography (OCT). Results: The fovea and the central sector of the retina in amblyopic eyes were slightly but not significantly thicker than those in the normal fellow eyes. There was no significant difference in any section of macular thickness between amblyopic and fellow eyes (p > 0.05). In addition, no significant differences in thickness were found between the retinal nerve fibre layers of amblyopic and normal fellow eyes (p > 0.05). Conclusion: There were no differences in the thickness of the foveal and the retinal nerve fibre layers found between eyes with esotropic amblyopia and the normal fellow eyes in children aged seven to 14 years.
收起
摘要 :
To investigate the effects of rigid-gas-permeable contact lens (RGP-CL) wear on Zernike astigmatism and visual performance in myopic eyes. Methods: A wavefront sensor was used to evaluate Zernike astigmatism for 21 eyes with minim...
展开
To investigate the effects of rigid-gas-permeable contact lens (RGP-CL) wear on Zernike astigmatism and visual performance in myopic eyes. Methods: A wavefront sensor was used to evaluate Zernike astigmatism for 21 eyes with minimum astigmatism and 18 eyes with moderate astigmatism under three different modes of refractive correction: the RGP-CL, spectacle lens correcting spherical equivalent (SL) and spectacle lens fully correcting spherical error and astigmatism (fSL). Contrast visual acuity was assessed with a VA tester at four contrast levels and two luminance backgrounds. Results: Compared to the SL wear, RGP-CL wear changed the main axis astigmatism (Z _2 ~2) from -0.09 ± 0.34 to 0.34 ± 0.22 for the minimum astigmatism group, while the contrast VA was improved about 0.05 LogMAR (F = 8.06, p < 0.01). For the group with moderate astigmatism, significant reduction in Z 2 2 was found for both fSL wear (t = 4.78, p < 0.001) and RGP-CL wear (t = 6.29, p < 0.0001). The changes in astigmatism were significantly correlated between the fSL and RGP-CL wears (r = 0.897, p < 0.0001 for Z _2~(-2); and r = 0.643, p = 0.004 for Z _2 ~2. Contrast VA was significantly improved for both fSL and RGP-CL wears and the improvements were significantly correlated between each other for all four contrast levels and two backgrounds. Conclusion: RGP-CL wear induces astigmatism for the eyes with minor astigmatism probably due to a correction of corneal astigmatism and thus a manifesting of the lens astigmatism. For the astigmatic eyes, RGP-CL wear has similar effect on correcting astigmatism as the spectacle lens wear with spherical-cylinder correction and also produces similar visual improvement.
收起
摘要 :
PURPOSE: To investigate the fluctuations of directly measured intraocular pressure (IOP) and induced diastolic ocular perfusion pressure (DOPP) during three simulated steps of phacoemulsification in vivo. METHODS: Twenty-five eyes...
展开
PURPOSE: To investigate the fluctuations of directly measured intraocular pressure (IOP) and induced diastolic ocular perfusion pressure (DOPP) during three simulated steps of phacoemulsification in vivo. METHODS: Twenty-five eyes of 25 patients who underwent phacoemulsification were evaluated. A pressure transducer was inserted into the anterior chamber to measure IOP directly. The cortical cleanup and viscoelastic removal, nuclear disassembly, and anterior capsular polishing stages of phacoemulsification were simulated. Baseline, static, and dynamic IOP measurements at each stage were conducted before a routine phacoemulsification procedure was performed. DOPP was determined as the difference between diastolic blood pressure and IOP. RESULTS: The directly measured IOP fluctuated from 13 +/- 4.7 to 96 +/- 6.2 mm Hg during the simulated steps of phacoemulsification (repeated-measurement ANOVA, P < 0.001). It was elevated more than 39 mm Hg compared with the baseline in static and dynamic measurements (post hoc, P < 0.001). Static DOPPs were lower than 0 mm Hg in all cases during simulated cortical cleanup and viscoelastic removal and in 19 cases during simulated nuclear disassembly. Dynamic DOPPs were lower than 0 mm Hg in 14 cases during simulated cortical cleanup and viscoelastic removal. CONCLUSIONS: IOP and DOPP fluctuate widely during simulated steps of phacoemulsification. Further studies may be needed to establish the effect of the transient fluctuations in DOPP on visual function.
收起
摘要 :
PURPOSE: To investigate the fluctuations of directly measured intraocular pressure (IOP) and induced diastolic ocular perfusion pressure (DOPP) during three simulated steps of phacoemulsification in vivo. METHODS: Twenty-five eyes...
展开
PURPOSE: To investigate the fluctuations of directly measured intraocular pressure (IOP) and induced diastolic ocular perfusion pressure (DOPP) during three simulated steps of phacoemulsification in vivo. METHODS: Twenty-five eyes of 25 patients who underwent phacoemulsification were evaluated. A pressure transducer was inserted into the anterior chamber to measure IOP directly. The cortical cleanup and viscoelastic removal, nuclear disassembly, and anterior capsular polishing stages of phacoemulsification were simulated. Baseline, static, and dynamic IOP measurements at each stage were conducted before a routine phacoemulsification procedure was performed. DOPP was determined as the difference between diastolic blood pressure and IOP. RESULTS: The directly measured IOP fluctuated from 13 +/- 4.7 to 96 +/- 6.2 mm Hg during the simulated steps of phacoemulsification (repeated-measurement ANOVA, P < 0.001). It was elevated more than 39 mm Hg compared with the baseline in static and dynamic measurements (post hoc, P < 0.001). Static DOPPs were lower than 0 mm Hg in all cases during simulated cortical cleanup and viscoelastic removal and in 19 cases during simulated nuclear disassembly. Dynamic DOPPs were lower than 0 mm Hg in 14 cases during simulated cortical cleanup and viscoelastic removal. CONCLUSIONS: IOP and DOPP fluctuate widely during simulated steps of phacoemulsification. Further studies may be needed to establish the effect of the transient fluctuations in DOPP on visual function.
收起
摘要 :
PURPOSE. To investigate thickness profile changes of the corneal epithelium and Bowman's layer at the vertical and horizontal meridians with overnight myopia orthokeratology (OK) lenses. METHODS. Twenty subjects (age range: 19-33 ...
展开
PURPOSE. To investigate thickness profile changes of the corneal epithelium and Bowman's layer at the vertical and horizontal meridians with overnight myopia orthokeratology (OK) lenses. METHODS. Twenty subjects (age range: 19-33 years) wore reverse-geometry rigid gas-permeable OK lenses in both eyes for 30 days. Before lens wear and after 1, 7, and 30 days of overnight lens wear, evaluation of lens fitting, visual acuity examination, corneal topography, and ultra-high resolution optical coherence tomography (UHR-OCT) were performed. The central, midperipheral, and peripheral cornea were imaged in both the horizontal and vertical meridians. Custom software was produced to acquire the thickness profiles of the epithelium and Bowman's layer. RESULTS. Unaided visual acuity and refraction were improved significantly after OK lens wear. The central corneal epithelium thinned in the horizontal and vertical meridians after one night of lens wear (P < 0.05). In the horizontal meridian, the epithelium thickened at the temporal and nasal midperipheries (P < 0.05), while the superior midperipheral epithelium thinned in the vertical meridian. There were no changes in the thickness profile of Bowman's layer during the study period. CONCLUSIONS. Overnight wear of OK lenses caused the central corneal epithelium to thin in both the vertical and horizontal meridians, while the midperipheral nasal and temporal epithelium became thicker and the superior midperipheral epithelium became thinner. The thickness of the central or midperipheral Bowman's layer in either meridian did not change. Improved vision acuity after overnight OK lens wear can be attributed to changes in the corneal epithelium and not Bowman's layer.
收起
摘要 :
Aim: To investigate the correlation between corneal biomechanical properties, applanation tonometry and direct intracameral tonometry. Methods: Patients scheduled for phacoemulsification were enrolled in this prospective observer-...
展开
Aim: To investigate the correlation between corneal biomechanical properties, applanation tonometry and direct intracameral tonometry. Methods: Patients scheduled for phacoemulsification were enrolled in this prospective observer-masked study. Central corneal thickness (CCT) was obtained with ultrasound pachymetry. Corneal biomechanical properties including corneal hysteresis (CH) and corneal resistance factor (CRF) were measured with the ocular response analyser. Applanation intraocular pressure (IOP) (IOPappla) was measured in the supine position. Intracameral IOP (IOPintra) was measured with a pressure transducer connected to a cannula inserted into the anterior chamber. Results: Fifty-eight eyes of 58 patients were included. There was a significant difference between IOPappla and IOPintra (17.364.1 vs 13.864.7 mm Hg, p<0.001). CCT was significantly correlated with CH and CRF (p<0.01). Univariate regression analysis revealed IOPappla was significantly correlated with CCT and CRF (p<0.05). IOPintra had no significant association with the corneal properties (p>0.05). Multivariate regression analysis revealed IOPappla=10.43+2.69CRF-1.99CH (p<0.001) and the difference between IOPappla and IOPintra (ΔIOP)=-1.57+0.55CRF (p=0.032). Conclusion: The mean difference between IOPappla and IOPintra was 3.5 mm Hg. While IOPappla was correlated with the corneal biomechanical properties of CH and CRF, IOPintra was not. IOPappla was correlated more with the corneal biomechanical properties assessed by the ocular response analyser than with CCT alone. determined whether differences were correlated with the corneal biomechanical properties measured by the ORA.
收起
摘要 :
Objective: To test accuracy and repeatability of a software algorithm that performs automatic biometry of the anterior segment of the human eye imaged with long scan depth optical coherence tomography (OCT). Methods: The ocular an...
展开
Objective: To test accuracy and repeatability of a software algorithm that performs automatic biometry of the anterior segment of the human eye imaged with long scan depth optical coherence tomography (OCT). Methods: The ocular anterior segment imaging was performed with custom-built long scan depth OCT. An automatic software algorithm including boundary segmentation, image registration, and optical correction was developed for fast and reliable biometric measurements based on the OCT images. The boundary segmentation algorithm mainly used the gradient information of images and applied the shortest path search based on the dynamic programming to optimize the edge finding. The automatic algorithm was validated by comparison of the biometric dimensions between automatic and manual measurements and repeatability study. Results: Biometric dimensions of the anterior segment, including central corneal thickness, anterior chamber depth, pupil diameter, crystalline lens thickness, and radii of curvature of the anterior and posterior surfaces of lens, were obtained by the automatic algorithm successfully. There were no significant differences between the automatic and manual measurements for all biometric dimensions. The intraclass correlation coefficients (ICC) of agreement between automatic and manual measurements ranged from 0.85 to 0.98. The coefficients of repeatability and ICC for all automatic dimensions were satisfactory (1.1%-6.1% and 0.663-0.990, respectively). Conclusions: The high accuracy, good repeatability, and fast execution speed for automatic measurement of the anterior segment dimensions on the OCT images were demonstrated. The application of this automatic biometry is promising for investigating dynamic changes of human anterior segment during accommodation in real time.
收起
原文获取