Double-pass Optical Quality Analysis System Research Articles

A comparative study of visual quality between implantable collamer lens implantation and femtosecond LASIK for myopia

Background The incidence of myopia is gradually increasing, and how to choose a better corrective method of myopia for the best visual demand is very important. Objective This study was to compare visual quality of implantable collamer lens (ICL) implantation with femtosecond laser in situ keratomileusis (FS-LASIK) for moderate and high myopia using double-pass optical quality analysis system (OQAS). Methods A non-randomized controlled clinical trail was performed.Fifty-two eyes with -4.00 to -9.00 D of 26 consecutive patients were included in NO.1 Hospital of Xi'an from January 2015 to January 2016.Twenty-four eyes of 12 patients with the corneal thickness 0.05). All the patients were followed-up for 3 months after surgery.The preoperative best corrected distance visual acuity (BCDVA), spherical equivalent (SE), postoperative uncorrected distance visual acuity (UCDVA), BCDVA and SE were examined and compared between two groups.The parameters from OQAS were evaluated and intergrouply compared, including the objective scattering inders (OSI), modulation transfer function (MTF) cut off frequency, Strehl ratio and OQAS values under the contrast of 100%, 20% and 9%(OV100, OV20, OV9). Results The postoperative BCDVA was not significantly different from preoperative UCDVA in both ICL group and FS-LASIK group (-0.04±0.10 vs. 0.05±0.12; -0.07±0.12 vs.0.00±0.12) (t=3.128, 2.358, both at P>0.05). No statistically significant differnces were found in SE, UCDVA and BCDVA after operation between ICL group and FS-LASIK group (t=1.292, 0.900, -0.653, all at P>0.05). OQAS examination showed that MTF cut off, OSI, Strehl ratio, OV100 were not significantly different after operation between ICL group and FS-LASIK group (t=-2.032, -1.440, -0.224, all at P>0.05). The postoperative OV20 and OV9 were 0.82±0.14 and 0.80±0.21 in the ICL group, which were significantly higher than those in the FS-LASIK group(0.59±0.15 and 0.47±0.13)(t=4.105, 4.702, both at P<0.05). Conclusions Both ICL implantation and FS-LASIK provide good optical and visual quality for moderate to high myopic eyes, and ICL appears to have a better visual quality in comparison with FS-LASIK under the contrasts of 20% and 9%. Key words: Myopia/surgery; Refractive surgical procedure; Phakic intraocular lenses; Keratomileusis, laser in situ; Visual quality; Implantable collamer lens; Double-pass optical quality analysis system

Objective quantitative assessment of visual quality with a double-pass instrument for myopic foveoschisis patients

Objective To objectively quantitative assess the visual quality in patients with myopic foveoschisis (MF) using a double-pass optical quality analysis system (OQASⅡ). Methods Sixty-two subjects participated in this cross-sectional, observational study, who were divided into three groups based on the pathologic conditions including myopic foveoschisis group (MFG), myopic control group (MCG) and normal control group (NCG). Measurements with OQAS Ⅱ were performed for the modulation transfer function cut off frequency (MTF cut-off), the Strehl ratio (SR) and the objective scatter index (OSI). Visual data were analyzed using ANOVA and Pearson's correlation accompanied by logMAR BCVA and axial length (AL). Results The mean values for MTF cut-off, SR and OSI of MFG, MCG and NCG were 18.18±4.81, 0.13±0.03, 3.50±0.44; 22.87±2.66, 0.14±0.02, 2.42±0.29; 33.68±4.70, 0.23±0.02, 1.68±0.20 respectively, and statistical difference were proved except SR between MFG and MCG, or BCVA between MCG and NCG (P<0.05=. LogMAR BCVA and AL have negative correlations to MTF cut-off (r=-0.928, -0.658; P<0.05= and SR (r=-0.577, -0.893; P<0.05= with high coefficients in MFG. Log MAR BCVA has negative correlations to MTF cut-off and SR (r=-0.659, -0.806; P<0.05= in MCG. Log MAR BCVA has negative correlations to MTF cut-off and SR (r=-0.606, -0.602; P<0.05= and positively correlated to OSI (r=0.561, P<0.05= in NCG. Conclusions The mean value of BCVA, MTF cut-off, SR, OSI of myopic foveoschisis patients were lower than those myopic patients without foveoschisis and normal people. There exists a significant negative correlation between Log MAR BCVA, AL to MTF cut-off and SR. Compared with myopic and normal subjects, myopic foveoschisis have lower BCVA, MTF cut-off, SR but higher OSI. Key words: Vision, ocular; Vision tests; Retinoschisis; Myopia, degenerative/complications

Evaluation of double-pass optical quality analysis system between SMILE and femtosecond LASIK for myopia

Evaluation of double-pass optical quality analysis system between SMILE and femtosecond LASIK for myopia

Objective assessment of nuclear cataract: Comparison of double-pass and Scheimpflug systems

To compare the objective assessment of lens density by 2 systems (double-pass Optical Quality Analysis System and Pentacam Scheimpflug) in eyes with age-related nuclear cataract. Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea. Cross-sectional study. In eyes with age-related nuclear cataract, the objective lens density (0 to 100 points) was determined using the Scheimpflug system while subjective grading was achieved using the Lens Opacities Classification System III (LOCS III). The objective scatter index (OSI) (0 to 25) was assessed using the double-pass system. This study enrolled 47 patients (70 eyes). The mean OSI was 4.08 ± 2.22 (SD), and the mean Scheimpflug-measured lens density was 16.44 ± 4.36; the 2 parameters were correlated (r = 0.764, P<.01). There was a positive linear correlation between the OSI and LOCS III grading scores for nuclear opalescence and nuclear color (r = 0.772 and r = 0.752, respectively; P<.01). The cumulated dissipated energy (CDE) was strongly correlated with the OSI (r = 0.768) and Scheimpflug-measured lens density (r = 0.753). The OSI based on the double-pass system was correlated with the Scheimpflug-measured lens density, subjective lens grading, and CDE. The OSI may improve the preoperative evaluation of nuclear cataract and help predict phacodynamics in cataract surgery.

Evaluation of image quality after implantation of 2 diffractive multifocal intraocular lens models

To compare the visual quality after implantation of multifocal intraocular lenses (IOLs). Departments of Ophthalmology, Hospital Quirón and Hospital Clínico San Carlos, Madrid, Spain. In a prospective nonrandomized consecutive trial, patients had bilateral implantation of Acri.LISA 366D (Group A) or Tecnis ZM900 (Group B) multifocal IOLs. One eye of each patient was included in the study. Three months postoperatively, uncorrected and corrected distance and near visual acuities, pupil diameter, and refraction were assessed. The modulation transfer function (MTF), point-spread function (PSF), and light scattering were calculated using the double-pass Optical Quality Analysis System for distance vision with a 4.0 mm pupil diameter. Each IOL group comprised 20 patients. No statistically significant differences were found between the 2 groups in postoperative mean spherical equivalent or mean monocular corrected distance or near visual acuity. The PSF variables were slightly lower in Group B, although the difference between groups was not statistically significant. The MTF parameters (double-pass value at 100%, 20%, and 9% contrast) were slightly higher in Group A (P = .07, P = .04, and P = .09, respectively). The mean objective scatter index was 1.83 +/- 0.91 (SD) in Group A and 2.00 +/- 0.74 in Group B (P = .43). Both diffractive multifocal IOLs improved functional visual capacity at distance and near. Although the visual quality variables were slightly better in Group A than in Group B, the differences were not statistically significant.