ABSTRACT
Background Cornea astigmatism can be effectively corrected by implanting Toric intraocular lens (IOL) during cataract surgery and therefore improve visual acuity of patients.However,the decentration and rotation position errors were inevitable sometime.What's the difference of effect of position errors on quality of image between spherical IOL and Toric IOL needs further research.Objective This study was to evaluate the optical performance and wavefront with rotation and decentration of Toric IOL.Methods Different decentration for SN60AT IOL(spherical IOL) and Toric IOL in Hwey-Lan Lion model eyes was set with the role as follows:decentration 0.25 mm to 0.75 mm in a 5°-interval from 0° to 90°.Furthermore,Toric IOL was rotated at 5° and 10°,respectively.Then the image performances of SN60AT IOL and Toric IOL at different decentration distances and rotated degrees were evaluated with modulation transfer function (MTF) and value of wavefront aberration under all conditions.Results At the centration,the MTF curves of spherical IOL and Toric IOL were similar under 3,4 and 5 mm pupil diameter at each spatial frequency.Under the condition of 4 mm pupil diameter,when the decentration was 0.25 mm,the MTF values of SN60AT IOL at 6 c/d and 12 c/d were 0.581 087 and 0.411 960,respectively.T3 IOL were 0.454 259 and 0.382 313,T4 IOL were 0.426 020 and 0.360 490,T5 IOL were 0.425 606 and 0.359 877.When the decentration was 0.50 mm,the MTF values of SN60AT at 6 c/d and 12 c/d were 0.573 073 and 0.412 787,respectively.T3 IOL were 0.450943 and 0.379481,T4 IOL were 0.423 153 and 0.356 664,T5 IOL were 0.422 881 and 0.356 230.When the decentration was 0.75 mm,the MTF values of SN60AT at 6 c/d and 12 c/d were 0.560 038 and 0.413 624,respectively.T3 IOL were 0.445 597 and 0.374 322,T4 IOL were 0.418 522 and 0.350 087,T5 IOL were 0.418 468 and 0.349 976.When the IOL decentralized along 0°,5°,10°,90°meridian line,the MTF values were almostly same.The root mean square (RMS) of spherical IOL and Toric IOL was increased when the IOL decentralized from 0 mm to 0.75 mm,with the most increasing level in coma aberration and slight increase in trefoil aberration.When the T4 IOL decentralized from centre to 0.75 mm,the coma increased from 0 to C(3,-1)-0.049 79 μm,C (3,1)-0.037 59 μm and the trefoil aberration increased from 0 to C (3,3) 0.005 72 μm,C (3,-3) 0.004 64 μm.With the increase of rotation degrees (from 5°to 10°) of Toric IOL,the MTF was worse at high spatial frequency.Toric IOL rotation caused the increase of astigmatism and residual astigmatism and spherical error,but not high order aberration.Conclusions The tolerance of Toric IOL to decentration is very close to the spherical IOL,and optical performance is only associated with the amount of decentration but not direction.The aberration caused by Toric IOL decentration is mainly coma.The rotation of Toric IOL causes astigmatism error but not high order aberrations.
ABSTRACT
Background The residual astigmatism following Toric intraocular lens (IOL) rotation have received much attention.However,the variation of the optical performance and the wavefront abrrveation with Toric IOL rotation are unclear.Objective The aim of this study was to evaluate the optical performance,wavefront abrrveation and residual diopter spherical and cylinder lens with Toric IOL rotation.Methods T3,T4 and T5 Toric IOLs of +22.0 D were placed in Hwey-Lan Liou model eye respectively,with the posterior surface flat on the X axis and steep on the Y axis.Corneal astigmatism model was established by mimicing the model eye with Toric IOL using Zemax optical software.Then the Toric IOLs were rotated 5° to 10° individually under the 4 mm pupil diameter and 550 nm monochromatic light,and the image performance and wavefront abrrveation were recorded with all conditions,including modulation transfer function (MTF),out-of-focus aberration,astigmatism aberration,coma,trefoil aberration and spherical aberration.The refractive error of spherical power and cylinder power were calculated.Results Corneal astigmatism was fully corrected when Toric IOLs in the middle,and the MTF curves were near in T3,T4,T5 Toric IOLs.The image performance was worse under the high spatial frequency with the increase of rotation degrees of Toric IOLs,showing the gradually low of MTF curves,especially T5 Toric IOL.No obvious changes was seen in coma,trefoil aberration and spherical aberration after rotation of Toric IOLs,while out-of-focus aberration,astigmatism aberration were obviously increased.In addition,residual astigmatism and spherical error increase with the rotation of Toric IOLs.Conclusions Toricl IOL rotation leads to increase of astigmatism and spherical refractive error but not high order aberration.
ABSTRACT
Background Pentacam anterior segment analysis system (Pentacam) is more accurate in the quantitative evaluation of ocular anterior segment in primary angle-closure glaucoma (PACG) eyes than slit lamp microscope and ultrasound biomicroscope (UBM).However,its accuracy in the earlier stage of PACG before and after YAG laser peripheral iridotomy (LPI) is not fully elucidated.Objective This study was to assess the effect of YAG LPI in PACG patients with Pentacam.Methods A prospective self-controlled study was performed.Thirtyfive fellow eyes (pre-clinical stage of PACG) of acute PACG and 35 fellow eyes of chronic PACG were included in the Second Hospital of Hebei Medical University from July,2012 to December,2013.YAG LPI was performed on the eyes,and the parameters of ocular anterior segment including central anterior chamber depth (ACD),anterior chamber volume (ACV) and peripheral anterior chamber angle (ACA) were measured and compared by Pentacam before and 1 day,7 days,28 days after operation.This study was approved by the Ethic Committee of the Second Hospital of Hebei Medical University and informed consent was obtained from all subjects.Results In pre-clinical stage of PACG eyes,the postoperative ACD and ACV values were increased in comparison with preoperation,showing significant differences among various time points (ACD:F =6.783,P =0.004;ACV:F =19.090,P =0.000),and no significant difference was found in ACA among different time points (F =0.153,P =0.928).In the fellow eyes of chronic PACG,the postoperative ACD and ACV values were larger than those of preoperation,with significant differences among various time points (ACD:F =21.576,P =0.000;ACV:F =47.506,P =0.000),and no significant difference was found in ACA among different time points (F=0.581,P=0.629).The change values of ACD and ACV were (0.064±0.022) mm and (27.840±4.963) mm3 in the eyes of pre-clinical stage of PACG,and those in the fellow eyes of chronic PACG were (0.047-± 0.020) mm and (21.000 ± 3.278) mm3,showing significant differences between the two groups (ACD:t=2.783,P=0.008;ACV:t=5.749,P=0.000).Conclusions Pentacam allows easy,fast,automatic and non-contact quantification and three-dimension image of the anterior chamber parameters before and after YAG LPI in pre-clinical stage of PACG eyes and fellow eyes of chronic PACG.The ACD deepens and ACV increases after LPI in glaucomous eyes,especially in the pre-clinical stage of PACG eyes.
ABSTRACT
Background The optic quality of Toric intraocular lens (IOL)-implanted eye is affected by the residual astigmatism and individual difference of corneal spherical aberration and different magnification from steep and flat axis refraction.Whether correcting Toric IOL spherical aberration can effectively improve the image quality of individual patient is a question to be studied.Objective This study attempted to collect eye parameters of cataract patients to reconstruct the customized vision model by using Zemax optical software,and to evaluate the image performance with different Toric IOL spherical aberration.Methods A prospective study was performed.Forty-five eyes of 45 cataract patients were included in Second Hospital of Hebei Medical University from August 2012 to October 2013.Several relevant parameters were measured by Pentacam,including anterior and posterior surface height of cornea,corneal thickness,curvature radius of flat and steep meridians of anterior surface astigmatism,refractive diopter and curvature radius of posterior surface.The astigmatism of anterior and posterior corneal surface was described by Matlab 4.5 software.Corneal astigmatism model were set as aspheric state,and the effective position of Toric IOL was calculated using Holladay Ⅰ formula.Customized individual model eyes were constructed by Zemax software.The contrast sensitivity function (CSF) of different spherical Toric IOLs at different spatial frequencies were calculated and compared between 300 Td light environment with 3 mm pupil diameter (photopia light) and 0.3-1.0 Td light environment with 5 mm pupil diameter (mesopia light).This study was approved by Second Hospital of Hebei Medical University ethics committee,all the patients signed the informed consent.Results The mean astigmatism power was (1.51 ± 0.36) D and (1.49 ± 0.37) D,and the mean astigmatism meridian was (101.5 ± 59.8) ° and (101.9±58.5) ° in the model eyes and cataract eyes,respectively,without significant differences between them (t=0.886,0.652;both at P＞0.05).Bland-Altman test showed a good agreement in astigmatism power and astigmatism meridian between model eyes and cataract eyes.The LogCSF values at 1.5,3.0,6.0,12.0 and 18.0 c/d spatial frequencies were significantly higher in the aspherical Toric IOL model eyes than those in the spherical Toric IOL model eyes,and the LogCSF values at various spatial frequencies were significantly higher in the Toric IOLs with spherical aberrations of-0.13 μm and-0.26 μm than those in the zero spherical aberrations in both photopia light and mesopia light (all at P＜0.05).Conclusions A precise corneal astigmatism model based on cornea high data of cataract eyes was successfully constructed through special formulas with Zemax software.Aspherical Toric IOL can compensate for spherical aberration of cornea and enhance the optic quality in individual model eye.
ABSTRACT
Objective To investigate the surgical selection of retinal detachment with myopic macular holes. Methods Management strategies were adopted according to the ocular symptoms of patients with high myopia involved in posterior chorioretinal atrophy, the colour showed by the bottom of macular holes and the shape of posterior staphyloma. Seventy-five eyes of 72 patients fulfilled the study criteria. The patients were followed up in an average of eight-month-observation and were divided into three groups: single 16% C2F6 gas tamponade (26 eyes of 26 patients) as group A,vitrectomy combined with 16% C2F6 gas tamponade (26 eyes of 23 patients) as group B and vitrectomy with silicon oil tamponade (23 eyes of 23 patients) as group C. Results 69.2%(18/26) of the macular holes were closed in group A, 73.1%(19/26)in group B and 87.0% (20/23) in group C after the primary surgery. Comparison of postoperative outcomes,macular hole closure rate was not significantly different among three groups (P= 0.3184). Conclusions It suggests that good anatomic retinal reattachment be achieved using any approach. However, the optimal surgical choice regarding of the personality case offered less surgical burden and more rapid visual rehabilitation to patients.
ABSTRACT
OBJECTIVE@#To study the relationship between genetic polymorphisms of GSTM1 GSTT1 and the susceptibility of laryngeal and hypopharyngeal carcinomas (LHC).@*METHOD@#The GSTM1 and GSTT1 genotypes were determined by multiplex PCR analysis in 76 LHC patients and 76 population controls. The association between the genotypes and LHC risk was measured by odds ratios (ORs) and 95% confidence intervals (95% CIs).@*RESULT@#The frequency of GSTM1 null genotype was 59.2% in the LHC patients and 42.1% in controls (OR=1.935, 95% CI=1.069-3.510), the difference was significant (P0.05). In smokers, the risk of the LHC increased in subjects of GSTM1 null genotype (OR=5.545, 95% CI=2.158-13.528).@*CONCLUSION@#GSTM1 polymorphisms are associated with susceptibility to the LHC. It has the synergistic effects with smoking in the development of the LHC. GSTT1 genotypes might have no association with risk of the LHC in urban Linyi.
Subject(s)
Female , Humans , Male , Carcinoma, Squamous Cell , Genetics , Case-Control Studies , Disease Susceptibility , Gene Frequency , Genotype , Glutathione Transferase , Genetics , Hypopharyngeal Neoplasms , Genetics , Laryngeal Neoplasms , Genetics , Polymorphism, GeneticABSTRACT
Objective:To study the relationship between genetic polymorphisms of GSTM1 GSTT1 and the susceptibility of laryngeal and hypopharyngeal carcinomas(LHC).Method:The GSTM1 an GSTT1 genotypes were determined by multiplex PCR analysis in 76 LHC patients and 76 population controls.The association be tween the genotypes and LHC risk was measured by odds ratios(ORs)and 95% confidence intervals(95%Cls).Resuit:The frequency of GSTM1 null genotype was 59.2% in the LHC patients and 42.1% in controls(OR=1.935,95%CI=1.069-3.510),the difference was significant(P＜0.01).The frequency of GSTT1 null genotype was 57.9% in the LHC patients and 51.3% in controls.The difference was not significant(P＞0.05).In smokers,the risk of the LHC increased in subjects of GSTM1 null genotype(OR=5.545,95%CI=2.158-13.528).Conclusion:GSTM1 polymorphisms are associated with susceptibility to the LHC.It has the synergistic effects with smoking in the development of the LHC.GSTT1 genotypes might have no association with risk of the LHC in urban Linyi.