Effect of anterior capsule polishing on the visual quality after cataract surgery / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the effect of anterior capsule polishing on visual quality after phacoemulsification.METHODS: Prospective randomized control study. A total of 65 patients(73 eyes)with age-related cataract who underwent phacoemulsification combined with intraocular lens(IOL)implantation in the Emergency General Hospital between November 2021 and June 2022 were included. These patients were randomly assigned to two groups, with one group(anterior polishing group)underwent anterior and posterior capsule polishing(30 cases, 35 eyes), while the other(control group)receive routine posterior capsule polishing(35 cases, 38 eyes). Best corrected visual acuity was observed at 1wk, 1, 3 and 6mo after operation. Area of anterior capsule orifice was measured at 3 and 6mo after operation. Meanwhile, posterior capsular opacification(P score), IOL tilt and decentration were recorded by Pentacam Scheimpflug system. In addition, wavefront aberration, Strehl ratio(SR)of point spread function(PSF)and modulation transfer function(MTF)were evaluated by OPD-Scan Ⅲ.RESULTS: At 1wk, 1, 3 and 6mo after operation, best corrected visual acuity in anterior polishing group is significantly better than that of control group(P<0.05). There were no significant differences in area of anterior capsule opening, P score, IOL decentration, SR of PSF and MTF between two groups at 3 and 6mo after operation(P>0.05). At 3mo follow-up, no significant differences in IOL tilt and wavefront aberration were measured between two groups either(P>0.05). However, IOL tilt [(1.65±0.60)° vs.(2.34±0.43)°, P<0.001] and wavefront aberration(0.03±0.01μm vs. 0.06±0.03μm, P<0.001)in anterior polishing group were significant lower compared to control group at 6mo after operation.CONCLUSION: 360° polishing of anterior and posterior capsule during phacoemulsification can improve best corrected visual quality, with reduced IOL tilt, lower wavefront aberration and better visual quality.

Clinical efficacy of femtosecond laser-assisted cataract surgery combined with PanOptix trifocal intraocular lens implantation / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the clinical efficacy of femtosecond laser-assisted cataract surgery combined with PanOptix trifocal intraocular lens implantation.METHODS:The retrospective study enrolled 22 cases(26 eyes)of cataract patients who underwent femtosecond laser-assisted cataract surgery combined with PanOptix trifocal intraocular lens implantation from August 2020 to August 2021. Follow-up to 3mo after surgery, the changes of far, intermediate and near visual acuity, aberration, Strehl ratio(SR)and modulation transfer function cutoff(MTF-cutoff)frequency were compared. Defocus curve at 1mo postoperatively was made, and the visual quality and satisfaction were evaluated after 3mo of surgery.RESULTS: The visual acuity of all patients was better than 0.1(LogMAR)at the far, intermediate and near distance at 1d, 1wk, 1 and 3mo postoperatively, and it was significantly improved compared with those before surgery(all P<0.01). The defocus curve transitioned smoothly between +0.5 and -3.0D at 1mo after surgery, and visual acuity was better than 0.63. The total aberration and spherical aberration in the whole eye were significantly lower after surgery than before, and the SR and MTF-cutoff were significantly improved at 1d and 1wk after surgery(all P<0.05). With high satisfaction and good visual quality, patients could watch at far, intermediate and near distance without wearing glasses at 3mo after surgery.CONCLUSION: Femtosecond laser-assisted cataract surgery combined with PanOptix trifocal intraocular lens implantation gave patients a comfortable and satisfactory full-course vision.

Research progress of visual quality after SMILE / 国际眼科杂志(Guoji Yanke Zazhi)

Femtosecond laser small incision lenticule extraction(SMILE)is one of the most advanced corneal refractive operations at present. Different from other traditional corneal refractive operations, SMILE achieves minimally invasive and valveless operation. Therefore, the evaluation of postoperative visual quality of SMILE also has its own characteristics, at present, the latest research at home and abroad has confirmed that the naked eye vision can be significantly improved and the refractive status is stable after SMILE. However, there are different understandings of the objective visual quality indexes and their influencing factors, such as higher-order aberration, modulation transfer function cut off(MTF cut off)and objective scatter index(OSI)after SMILE. This paper reviews the postoperative visual quality and its influencing factors after SMILE to provide clinical help.

Analysis of changes of visual quality and vault height under different pupil diameters after ICL / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To observe the changes of the vault height and the correlation analysis of visual quality under different pupil diameters after ICL surgery.<p>METHODS: Retrospective case study. Selected 43 patients(86 eyes)who implanted V4c ICL surgery successfully at Shanghai Aier Eye Hospital and followed up regularly to meet the measurement requirements from January 2018 to January 2019, Routine parameters and iTrace were checked before and 1wk, 1mo, and 3mo after surgery. Visante-OCT was used to measure the vault height under the pupils of 3mm and 5mm. <p>RESULTS: The vault height under the 3mm pupil at 1wk, 1mo and 3mo after surgery were(586.06±24.49, 560.16±21.31, 508.19±21.17)μm, the values under the 5mm pupil were(698.13±20.98, 667.69±20.16, 613.28±19.79)μm(<i>F</i>_Time=40.160,<i>P</i>_Time<0.001; <i>F</i>_Groups=56.835,<i>P</i>_Groups<0.001). The wave of vaule under the different pupils was(112.06±8.91, 107.53±6.94,101.01±10.64)μm(<i>F</i>=16.875, <i>P</i>>0.05). The total high-order aberration(HOA)and RMS of the whole eye after ICL were significantly reduced(<i>F</i>=29.847, 85.019; <i>P</i><0.001). The MTF and SR value were significantly higher than before surgery(<i>F</i>=47.653, 33.264; <i>P</i><0.001), and there was no statistical difference after ICL. At 3mo after surgery, the RMS and MTF values at 3mm and 5mm pupils were compared. The RMS value of the total HOA under the pupil of 5mm is significantly higher than that at 3mm, and the increase of spherical and trefoil aberration is significant(<i>t</i>=21.812, 17.136; <i>P</i><0.001). No significant difference in coma value(<i>t</i>=2.028, <i>P</i>>0.05). The MTF at 5mm pupils were significantly lower than those at 3mm at spatial frequencies of 5, 10, 15, 20, 25, 30c/d(<i>t</i>=15.138, 9.147, 7.018, 4.693, 3.814 and 3.075, all <i>P</i><0.05).<p>CONCLUSION: The impact of pupil movement on vault height fluctuation is about 110μm. It is recommended that the minimum vault height should be above 300μm. It can significantly reduce the root mean square value of total high-order aberration and aberration of the whole eye, and significantly increase the MTF and SR values after ICL surgery. The pupil size has a significant effect on visual quality after ICL. The spherical aberration and trefoil aberration increase under the condition of large pupil, and the MTF value generally decreases.

Comparison of modulation transfer function between the eyes after small-incision lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis / 中华实验眼科杂志

Objective:To investigate and compare the changes of modulation transfer function (MTF) after small-incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK).Methods:A cohort study was conducted.One hundred and two myopic patients (102 eyes) who underwent SMILE and FS-LASIK in Tianjin Eye Hospital from December 2015 to June 2016 were enrolled and divided into SMILE group with 53 eyes and FS-LASIK group with 49 eyes according to different surgical methods.The ocular aberrations and corneal morphology of all patients were measured by the Hartman-Shack wave-front analyzer and Pentacam topography before surgery and 1, 3 and 6 months postoperatively.MTF of optic system was calculated and analyzed.The changes of MTF values were compared between the two groups at different time points under different spatial frequencies, after removal of low-order aberrations at postoperative 6 months, and after removal of vertical coma aberration, horizontal coma aberration and spherical aberration in the SMILE group at postoperative 6 months.The study protocol complied with the Declaration of Helsinki and was approved by an Ethics Committee of Tianjin Eye Hospital (No.TJYYLL-2014-17). Written informed consent was obtained from each patient before surgery.Results:Compared with the preoperative MTF, there were significant increases in postoperative 1-, 3- and 6-month MTF at all spatial frequencies in the SMILE group and FS-LASIK group (all at P<0.05). MTF values at all spatial frequencies in the SMILE group were significantly higher than those in the FS-LASIK group at 1, 3, and 6 months after surgery (all at P<0.05), except at 55 c/d and 60 c/d at 6 months postoperatively.The postoperative 6-month MTF values at all spatial frequencies without low-order aberration were higher in the SMILE group than those in the FS-LASIK group, showing significant differences between the two groups (all at P<0.05). In the SMILE group, the postoperative 6-month MTF values at 1 c/d spatial frequency without the horizontal coma aberration and spherical aberration were significantly higher than the preoperative MTF values (both at P<0.01); the postoperative 6-month MTF values at 1 c/d and 3 c/d spatial frequency without vertical coma aberration were significantly higher than the preoperative MTF values (both at P<0.05), and there were no statistically significant differences between the postoperative 6-month MTF values at the other spatial frequencies with and without single high-order aberrations (all at P>0.05). Conclusions:Optic quality has been obviously improved after SMILE and FS-LASIK, and the SMILE is superior to FS-LASIK in the MTF value.

Evaluation of the relationship between visual quality and optical modulation transfer function after SMILE / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the characteristics of optical modulation transfer function(MTF)of the eyes after femtosecond laser small incision lenticule extraction(SMILE), and to evaluate the relationship between visual acuity(VA), contrast sensitivity(CSF)and MTF. <p>METHODS: From June to November, 2015, 34 myopia patients(68 eyes)who underwent SMILE surgery in Tianjin Eye Hospital were selected in cross-section. The postoperative eye condition was stable for more than 3mo after surgery. The residual diopter of the eyes after SMILE was less than ±0.50D. Under bright vision, measured VA by International standard visual acuity chart and CSF by CSV-1000E. The wavefront aberration of the whole eyes were measured by WaveScan, and MTF of the eyes were obtained by using aberration formula conversion and Matlab programming. The MTF of(3, 6, 12, 18)c/d frequency region were counted. <p>RESULTS: CSF values in 3, 6, 12, 18 c/d frequency range were 63.19±3.18, 110.25±5.22, 57.65±3.76, 16.15±1.04; MTF values in 3, 6, 12, 18 c/d frequency range were 0.80±0.02, 0.56±0.03, 0.30±0.02, 0.19±0.02. In 6, 12, 18 c/d frequency range, visual acuity was significantly correlated with CSF(<i>r</i>=0.548, 0.337, 0.324,<i> P</i><0.01,=0.005, 0.007). In 18c/d frequency range, CSF was significantly correlated with MTF(<i>r</i>=0.241,<i> P</i>=0.048). <p>CONCLUSION: The change of optical quality(MTF)after SMILE was different from that of visual quality(visual acuity and contrast sensitivity). Although the aberration of refractive system changed, the SMILE surgery had no effect on CSF, which indicated that neuro-brain had a compensatory effect on visual quality. Computational MTF has certain theoretical and clinical value in evaluating the optical quality after refractive surgery.

Long-term clinical effect of aspheric multifocal intraocular lens implantation for developmental cataracts in childhood / 中华实验眼科杂志

Objective To observe the long-term visual quality and clinical effect of aspheric diffractive multifocal intraocular lens (IOL) implantation for congenital and developmental cataracts in childhood.Methods A retrospective cohort study on multifocal IOL implantation for congenital and developmental cataracts in childhood (aged 8 to 14 years) was performed in the First Affiliated Hospital of Zhengzhou University from August 2013 to January 2015.The clinical data of 67 eyes from 46 congenital cataract patients who received phacoemulsification with IOL implantation were collected.The AMO (ZMB00) IOL was implanted in 34 eyes of 24 patients in the multifocal IOL group,and Bausch & Lomb (MI60) IOL was implanted in 33 eyes of 22 patients in the monofocal IOL group.The distance,intermediate and near vision acuity were analyzed in 3,6 and 12 months after surgery,including uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA).The wavefront aberrations,modulation transfer functions (MTF) and stereopsis were obtained with iTrace Analysis System,Optec-6500 Visual Functional Analyzer and Titmus Stereo Test Chart,respectively in 12 months after surgery.The near additional degree,removing glasses rate and myopic shift were compared between the two groups in postoperative 12 months.Results The intermediate and near UCVA in the multifocal IOL group were obviously better than those in the monofocal IOL group 3,6 and 12 months after surgery (intermediate:Z=-3.74,-4.36,-3.66;all at P=0.00.near:Z=-2.67,-2.50,-2.33;all at P＜0.05).There were no significant differences between the two groups in total aberration,high and low order total aberrations,comatic aberration,trefoil aberration,spherical aberration and secondary astigmatism under the 5.0 mm optical zone in 12 months after surgery (all at P＞0.05).The MTFs under the 5.0 mm optical zone and 5,10,15,20,25,30 c/d in the multifocal IOL group were insignificantly lower than those in the monofocal IOL group (all at P＞0.05).In addition,the near stereopsis,near additional degree and myopic shift (AD) were reduced in the multifocal IOL group compared with monofocal IOL group (both at P＜0.05).The glasses removing rate was 93.3％ in the multifocal IOL group,which was significantly higher than 33.3％ in the monofocal IOL group (x2 =23.25,P =0.00).No significant difference in the incidence of posterior capsular opacification was found between the two groups (P＞0.05).The myopic shifting rates were 16.7％ and 83.3％ in the multifocal IOL group and monofocal IOL group,with a significant difference between the two groups (x2=15.02,P=0.00).Conclusions The aspheric multifical IOL implantation can achieve good and stable distance,intermediate and near visual acuities,provide better near stereopsis,reduce postoperative dependence on spectacles and decrease the incidence of myopic shift in child cataract patients.

Optical imaging quality change of multifocal intraocular lens following Nd∶YAG laser damage / 中华实验眼科杂志

Objective To study the optical imaging quality of multifocal intraocular lens (IOL) following Nd∶YAG laser damage.Methods Three hydrophobic acrylate discs used to make multifocal IOL were placed in line,and the Nd∶YAG laser was used to emit the posterior surface,mid-plane and anterior surface of the discs by gradually increasing the emitting energy to determine the damaged threshold energy of various planes.Eight multifocal IOLs were divided into 2 groups.IOL damage models were established by emitting 12 points along 12 clocks on circle of 3.0 mm in diameter in the group 1 (IOLs NO.1,2,3,4) and 6 points with 1-clock interval on circle of 1.0 mm in diameter in the group 2 (IOLs NO.5,6,7,8) with Nd∶YAG laser.The modulation transfer function (MTF),line spread function (LSF) and United States air force (USAF) test target images of the IOLs were tested under the optical aperture at 2.0,3.0 and 4.5 mm.Results The damage thresholds of laser power were not significantly different among three hydrophobic acrylate discs (Fgroup =1.100,P =0.337),and the thresholds were significantly different among different planes in the discs (Fposition =195.279,P=0.000),with the highest damage threshold in the anterior surface and the lowest damage threshold in the mid-plane of the discs(all at P＜0.01).The shifts of far focus and near focus MTF curves,LSF curves and USAF target images of the IOLs under the 2.0,3.0 and 4.5 mm optical aperture after laser damage were in coincidence with those before laser damage both in group 1 and group 2.The glare phenomenon of the USAF target image was observed at near focus under the 4.5 mm optical aperture both before and after laser damage.Conclusions Multifocal IOL is vulnerable to injury when the laser beam focuses on the midplane,and the anterior surface of IOL can tolerate certain degree of damage.In standard model eye,the MTF curves,LSF curves and USAF target images of multifocal IOL was not impacted by laser induced spots injuries under different pupil diameters.

Application of Deconvolution Algorithm of Point Spread Function in Improving Image Quality: An Observer Preference Study on Chest Radiography

OBJECTIVE: To evaluate the preference of observers for image quality of chest radiography using the deconvolution algorithm of point spread function (PSF) (TRUVIEW ART algorithm, DRTECH Corp.) compared with that of original chest radiography for visualization of anatomic regions of the chest. MATERIALS AND METHODS: Prospectively enrolled 50 pairs of posteroanterior chest radiographs collected with standard protocol and with additional TRUVIEW ART algorithm were compared by four chest radiologists. This algorithm corrects scattered signals generated by a scintillator. Readers independently evaluated the visibility of 10 anatomical regions and overall image quality with a 5-point scale of preference. The significance of the differences in reader's preference was tested with a Wilcoxon's signed rank test. RESULTS: All four readers preferred the images applied with the algorithm to those without algorithm for all 10 anatomical regions (mean, 3.6; range, 3.2–4.0; p < 0.001) and for the overall image quality (mean, 3.8; range, 3.3–4.0; p < 0.001). The most preferred anatomical regions were the azygoesophageal recess, thoracic spine, and unobscured lung. CONCLUSION: The visibility of chest anatomical structures applied with the deconvolution algorithm of PSF was superior to the original chest radiography.

Evaluation of long-term optical quality after laser in situ keratomileusis for myopia / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To evaluate the stabilization of long-term optical quality after laser <i>in situ</i> keratomileusis(LASIK)for myopia by Optical Quality Analysis System.<p>METHODS: Totally 70 eyes from 35 student volunteers after LASIK and 140 eyes from 70 normal student volunteers were recruited from the Fourth Military Medical University. The volunteers after LASIK were divided into recent observation group(2～4a after LASIK)and long-term observation group(5～10a after LASIK). The normal volunteers were divided into recent control group and long-term control group,to analysis the influence of confounding factors such as age and eyes-using habit on the optical quality. The observation groups and the control groups were compared respectively. The objective scattering index(OSI), modulation transfer function cutoff frequency(MTF cutoff), Strehl ratio(SR),OQAS value in 100% contrast(OV100%), OQAS value in 20% contrast(OV20%), OQAS value in 9% contrast(OV9%)were analyzed. <p>RESULTS: The OSI of observation group improved significantly but the MTF cutoff, SR, OV100%, OV20% and OV9% decreased significantly in several years after LASIK(<i>P</i><0.05). The optical quality is generally stable after LASIK. The OSI had a tendency to reduce and the MTF cutoff, SR, OV100%, OV20% and OV9% had a tendency to improve, but showed no significant difference.<p>CONCLUSION: LASIK, one of the most frequent operation methods for myopia correction, can reduce the optical quality in a certain extent. The optical quality has a tendency to recover in several years after LASIK, but not completely. OQAS is a feasible method in assessing the long-term optical quality after LASIK.

A quantitative evaluation of quality control image for on-board imaging system of medical linear accelerator / 中华放射肿瘤学杂志

Objective To establish a quantitative evaluation of quality control image for the onboard imaging system of medical linear accelerator.Methods An MV planar image of electronic portal imaging device (EPID) is acquired by both Elekta iViewGT and Varian aS1000,and a kV planar image and cone-beam computed tomography (CBCT) images of CBCT are acquired by both Elekta X-ray volume imaging (XVI) and Varian On-board Imager (OBI).Phantoms used here included Las Vegas,TOR18FG,and Catphan504.A series of image quality indicators were evaluated by analyzing the images mentioned above using a quantitative method.Results A quantitative value was calculated to represent the contrast resolution of EPID.A modulation transfer function (MTF) to describe spatial resolution and a quantitative value representing contrast resolution were calculated for the kV planar image.As for the CBCT system,a series of quantitative results of noise,uniformity,CT value accuracy,and contrast resolution and a MTF were calculated to represent the performance of CBCT system.Conclusions Based on common phantoms,a complete set of quantitative methods to evaluate the image quality of EPID and CBCT has been developed,which could provide a very good reference for the establishment of quality control system for image-guided radiotherapy.

Effects of astigmatism values of children on wavefront aberration / 眼科新进展

Objective To investigate the effects of the astigmatism values of children on wavefront aberration.Methods The children aged from 7 years to 10 years were dilated the pupils for 3 days,and the optometry examination was performed.Fifty-nine children who met the inclusion criteria were divided into three groups according to the degree of astigmatism:1.00 D ≤ astigmatism ＜2.00 D,2.00 D ≤ astigmatism ＜ 3.00 D,3.00 D ≤ astigmatism ＜ 4.00 D.In the meantime,OPD-SCAN-Ⅲ aberrometer was used to measure corneal topography,point spread function (PSF),modulation transfer function(MTF) and other optical images.Total higher order aberrations,total coma aberration,total spherical aberration,total trefoil aberration corresponding to the root mean square (RMS) value and the area ratio (AR) value of MTF,the strehl ratio (SR) value of PSF with a 4 mm pupil diameter were assessed.Three groups of higher order aberrations corresponding to the RMS value and the AR value of MTF,the SR value of PSF were respectively compared by one-way ANOVA.Results The RMS of total high-er order aberrations,coma aberrations and trefoil aberrations with a 4 mm pupil diameter of three groups significantly increased with the degree of astigmatism increase,and there were significant differences among three groups (all P ＜ 0.05).The RMS of total spherical aberrations of three groups significantly increased with the degree of astigmatism increase,and there was no significant difference among three groups (P ＞ 0.05).The AR and SR values decreased with the degree of astigmatism increase,and there were significant differences among three groups (all P ＜ 0.05).Conclusion Astigmatism has a significant influence on the higher-order aberrations,MTF and PSF in the children with the rule astigmatism.The rule astigmatism mainly has an effect on the asymmetric components of higher order aberrations.

Effect of tear film stability on visual quality after femtosecond laser-assisted LASIK / 中华实验眼科杂志

Background The instability of tear film in dry eye often affects the visual quality after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK).The prediction for visual quality following FS-LASIK was difficult in the past because of the limiting of examination method.OQAS-Ⅱ is a quantitative checking system of visual quality,which is helpful for the evaluation of the relationship between tear stability and visual quality following FS-LASIK.Objective This study was to investigate the predicting effects of the quality of tear film on visual quality after LASIK.Methods A prospective cohort study was performed.One hundred and twenty eyes of 120 myopic patients who wanted to receive FS-LASIK were enrolled in Nanjing First Hospital from August to December 2015 after informed consent.The objective scattering index (OSI) was 1.2 in the patients.The patients were divided into mild dry eye group (71 eyes) and non-dry eye group (49 eyes) based on the Expert Consensus on Clinical Diagnosis and Treatment of Dry Eye(2013).FS-LASIK was performed in the non-dry eye group,and 0.1％ sodium hyaluronate eye drops was topically administered for 1 month firstly and then the operation was carried out in the same way in the mild dry eye group.Slit lamp microscope,uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),spherical equivalent (SE) were examined,and the safety index and availability index were assessed.OQASTM Ⅱ analysis system was employed for the defection of Schirmer Ⅰ test (S Ⅰ t),breakup time of tear film (BUT),modulation transfer function cut-off frequency (MTF cut off) and mean OSI before and after surgery.Results The safety index was 1.05 ±0.11 and 1.03 ±0.09,and the availability index was 1.02±0.14 and 1.01 ± 0.12 in the non-dry eye group and mild dry eye group,respectively,showing significant differences between the two groups (t =0.391,0.147,both at P＞0.05).The BUT was evidently shortened 1 month and 3 months after surgery in comparison with before surgery in both non-dry eye group and mild dry eye group,and BUT in the mild dry eye group was shorter than that in the non-dry eye group in postoperative 3 months,with a significant differences between them (P＜0.05).The mean OSI was increased and MTF cutoff was reduced 1 month,3 months and 6 months after surgery in comparison with before surgery in both mild dry eye group and none-dry eye group,and mean OSI was higher and MTF cutoff was lower in the mild dry eye group than that in the non-dry eye group,with significant differences between them (all at P＜0.05).In postoperative 12 months,BUT,mean OSI and MTF cutoff were near normal in both groups.Conclusions FS-LASIK can improve objective visual quality,and preoperative tear film quality is associated with objective visual quality after FS-LASIK.The unstable tear film affects visual quality after FS-LASIK.OQASTM Ⅱ system can diagnose and monitor tear change of dry eyes,which is helpful for the screening of indicator of FS-LASIK and rational prediction of postoperative visual quality.

Assessment of corneal optical quality following small incision lenticule extraction for myopia / 中华实验眼科杂志

Background The current evaluation of corneal optical quality after small incision lenticule extraction (SMILE) is based on the single factor,such as scattering,diffraction or aberration,and all of them are not comprehensive and objective methods.Modulation transfer function (MTF) and Strehl ratio (ST) are novel parameters of corneal optical quality,which can be used to assess the optical quality comprehensively.Objective This study was to evaluate the change of MTF and SR under the photopic and scotopic environment (3 mm and 6 mm pupil size,respectively) after SMILE procedure.Methods The study protocol was approved by Ethic Committee of Tianjin Eye Hospital,and written informed consent was obtained from each patient before any medical procedure.A series cases-observational study with self-control design was carried out.Sixty-three eyes of 32 myopia or myopic astigmatism patients who underwent SMILE surgery in Tianjin Eye Hospital were included from December 2013 to March 2014.The uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA) (LogMAR),the effective index (postoperative UCVA/preoperative BCVA) and refractive diopter were examined,and the MTF,SR and root mean square (RMS) on the anterior corneal surface were measured under the 3 mm and 6 mm pupil size at different spatial frequencies (10,20,30,40,50 and 60 c/d) by Sirius anterior analyzer before surgery and 1 week,1 month and 3 months after surgery,respectively.Results UCVA was ≥0.8 in 59,62 and 63 eyes in 1 week,1 month and 3 months after SMILE,with the percentage of 93.65％,98.41％ and 100％,and the effective index was 1.104± 0.128,1.126±0.145 and 1.158±0.208,respectively.The refractive diopter was normal in the eyes at postoperative 3 months.The MTFs of various spatial frequencies on the vertical and horizontal meridian under the 3 mm pupil size after SMILE were significantly higher than those before SMILE,while under the 6 mm pupil size,the MTFs were higher only on vertical meridian and 10,20,30 and 40 e/d,and there were not significant differences on the horizontal meridian (all at P＜0.05).The SRs under the 3 mm and 6 mm pupil size showed increasing softly after surgery in comparison with before surgery,and the SRs were higher under the 3 mm pupil size than those under the 6 mm pupil size at various time points (all at P＜0.05).There were not significant differences in RMS among different time points under both 3 mm pupil size and 6 mm pupil size (3 mm pupil size:F =1.348,P =0.184;6 mm pupil size:F=1.990,P=0.137).Conclusions SMILE provides a great improvement in corneal optical quality for myopia or myopic astigmatism patients,which is more distinct in photopic condition than that in scotopic condition.

Dynamic assessment of tear-film stability-associated objective vision in mild or moderate dry eyes based on Optical Quality Analysis System parameters / 中华实验眼科杂志

Background The progenesis and development of dry eye is closely associated with the stability of tear-film.Dry eyes often show the visual disturbance.Therefore,to evaluate the stability of tear-film based on visual quality and explore the relevant dynamic vision change in dry eyes is of important significance.Objective The aim of this study was to evaluate the dynamic changes of objective scattering index (OSI),modulation transfer function cut off (MTF cut off),objective visual acuity (OVA) with tear-film in the patients with mild or moderate dry eye disease using Optical Quality Analysis System.Methods A clinical diagnosis test was performed.Forty-two eyes of 42 consecutive patients with mild or moderate dry eyes were included in Tianjin Eye Hospital from December 2013 to May 2014 based on ‘ The Clinical Diagnosis and Treatment Recommendations for Dry Eye from Consensus of Expert Advice in 2013’,and 29 normal eyes of age-and gender-matched 29 healthy volunteers were simultaneously included as the healthy control group.The dynamic retinal images under non-blinking condition during 15 seconds were recorded by OQAS-Ⅱ system,and the OSI,MTF cut off and OVA values at 0,5,10 and 15 seconds were obtained,and the differences of OSI,MTF cut off and OVA between 0 second and 15 seconds were calculated (△OSI,△MTF cut off,△OVA).The dynamic changes of △OSI,△MTF cut off and △OVA with time were evaluated.The sensitivity and specificity of △OSI,△MTF cut off and △OVA for the differential diagnosis of dry eyes were analyzed by receiver operating characteristic curve (ROC curve).Results The OSI values at 5,10 and 15 seconds in the mild or moderate dry eye group were significantly higher than those at 0 second or those in the healthy control group (all at P＜0.05),and the MTF cut off values and OVA values at 5,10 and 15 seconds in the mild or moderate dry eye group were significantly lower than those at 0 second or those in the healthy control group (all at P＜0.05).The △OSI,△MTF cut off and △OVA values were 1.03±1.53,(-8.37±9.64)c/d and-0.30±0.32 in the mild or moderate dry eye group,which were significantly higher than 0.06± 0.16,(-0.37 ± 5.27) c/d and-0.03 ± 0.18 in the healthy control group (t=4.10,-5.19,-5.28,all at P＜0.05).The area under ROC curve was 0.90,0.79 and 0.78 in △OSI,△MTF cut off and △OVA,respectively.The sensitivity and specificity of △OSI was 78.6％ and 93.1％ respectively at the diagnostic cut off of 0.3.Conclusions The optical quality parameters related with tear-film stability are gradually reduced with extending of time in mild or moderate dry eyes,but they are stable in healthy eyes.The detecting outcomes by OQAS-Ⅱ system can reflect the dynamic status of tear-film,and this method is of important clinical value for the differential diagnosis and optical quality evaluation in dry eyes.

Optical performance of Toric intraocular lens rotation in Hwey-Lan Liou model eye / 中华实验眼科杂志

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.

Changes of visual quality after Nd:YAG laser posterior capsular dissection to the patient with after-cataract / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To observe and analyze visual quality changes of the patients with posterior capsule opacification ( PCO ) Nd:YAG laser posterior capsular dissection, including the change of the best corrected vision acuity ( BCVA ) , total high- order aberration ( tHOA ) , and the modulation transfer function ( MTF) . METHODS:In this prospective observational study, 100 cases of patients ( 100 eyes ) with posterior cataract underwent Nd:YAG laser posterior capsular dissection ( posterior capsular diameter dissected was 5mm or higher). The mean age was 65. 52±7. 01 years old. The change of the BCVA was collected. The tHOA and MTF under the 3mm and 5mm pupil diameter were assessed by iTrace respectively before and after Nd:YAG laser posterior capsular dissection. RESULTS:All the surgery went well without obvious intraoperative and postoperative complications happened. The preoperative BCVA was 0. 451 ± 0. 023 while the postoperative BCVA was 0. 763±0. 025. The difference of BCVA before and after Nd: YAG laser surgery was statistically significant (PCONCLUSION: Patients with posterior capsule opacification ( PCO ) Nd:YAG laser posterior capsular dissection can help improve BCVA, reduce tHOA, increase MTF tHOA values, and significantly improve visual quality of patients.

Comparing Clinical Results after Intraocular Lens Implantation Surgery Using Three Other Aspheric Lenses

PURPOSE: We compared the clinical results after implantation of the newly-developed aspheric intraocular lens iSert 250 NC60 (Hoya Corporation Ltd., Tokyo, Japan) with 2 other types of widely used intraocular lenses, AcrySof IQ SN60WF (Alcon Laboratories, INC., Fort Worth, TX, USA) and TECNIS 1-piece ZCB00 (AMO Inc., Santa Ana, CA, USA). METHODS: Seventy cataract eyes were implanted with 1 of 3 aspheric intraocular lenses (Hoya iSert 250 NC60, TECNIS 1-piece ZCB00 or AcrySof IQ SN60WF) by the same surgeon. Uncorrected vision, best corrected vision, spherical equivalent, higher order aberrations, and modulation transfer function were measured 1 and 3 months after the cataract surgery. RESULTS: Uncorrected vision and best corrected vision were not significantly different among the 3 groups; however, eyes implanted with iSert250 NC60 showed more hyperopic-shifted postoperative spherical equivalents than expected compared to the other 2 groups. Total ocular aberrations and internal optics aberrations were similar among the 3 groups while the root mean square of the corneal aberrations showed differences. Eyes implanted with iSert 250 NC60 showed superior results in modulation transfer function compared with the other 2 groups in a majority of spatial frequencies 3 months postoperatively. CONCLUSIONS: The newly developed aspheric intraocular lens iSert 250 NC60 showed clinically equal results compared with 2 other verified intraocular lenses AcrySof IQ SN60WF and TECNIS 1-piece ZCB00 in vision, higher-order aberrations, and modulation transfer functions.

Analysis of the point spread function in total corneal of normal population / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To explore relationship between the normal strehl ratio ( SR ) values of total aberrations/SR values of total higher-order aberrations and modulation transfer function ( MTF ) at total corneal at different pupil diameters in normal population. METHODS: To exam the SR values of total aberrations and SR values of total higher-order aberrations of total corneals in 200 people ( 400 eyes ) using SIRIUS 3D topography system and analysis the corresponding root-mean-square ( RMS) . RESULTS: The subjects with different pupil diameters (3. 0, 5. 0, 6. 0, 7. 0mm)'s exam results of total corneal were as following:SR value of total aberrations 100’(0. 45±0. 12), (0. 25±0. 06), (0. 17±0. 05), (0. 13±0. 04); SR value of total higher order ab cerrations 100’(0. 69±0. 14), (0. 34±0. 07), (0. 24±0. 05), (0. 16±0. 04);SR value of total aberrations 200’(0. 45±0. 12), (0. 24±0. 06), (0. 20±0. 04), (0. 16±0. 03); SR value of total higher order aberrations 200’(0.70±0. 13), (0. 35±0. 07), (0. 27±0. 06), (0. 20±0.04 ) . The SR values of each group decreases with the increases of pupil diameters. The SR values of total aberrations and SR values of total higher - order aberrations at total corneals are negatively correlated with corresponding RMS value. When the pupil diameter is small, the SR value of total aberrations is more related to higher frequency region of MTF. When the pupil diameter is big, the SR value of total aberrations is more related to lower frequency region of MTF. CONCLUSION: The visual performance of normal people can be well reflected by SR values of total aberrations and SR values of total higher - order aberrations at total corneal.

Spatial resolution evaluation of 64-slice helical computed tomography / 医疗卫生装备

To put forward spatial resolution detection requirements of 64-slice helical CT based on analyzing the present situation of CT spatial resolution detection. The requirements for spatial resolution in the existing industrial standards were analyzed, and some test data were used to prove the deficiency of the standards. Spatial resolu-tion detection requirements were proposed for 64-slice helical CT, and the factors affecting spatial resolution were ex-plored. The deficiencies in the original standards were eliminated. The proposed requirements may facilitate the spatial resolution detection of 64-slice CT, and thus can enhance image quality for clinical diagnosis and treatment.