Modulation Transfer Function Cutoff Frequency Research Articles

Objective optical quality and visual outcomes after the PresbyMAX monocular ablation profile.

To assess objective visual quality after presbyopia correction using the PresbyMAX monocular mode. This prospective, nonrandomized study included 28 eyes from 18 patients (mean age 50.4±5.6y) who underwent presbyopia correction with the PresbyMAX monocular mode. Monocular and binocular visual acuities were evaluated preoperatively, 1d, 1wk, 1, 3mo, and 1y after surgery. Optical quality was analyzed by Hartmann-Shack wavefront aberration supported cornea ablation. Modulation transfer function (MTF) cutoff frequency, Strehl ratio, and objective scattering index (OSI) were analyzed using an optical quality analysis system. One year after surgery, 100% and 94.4% of patients achieved binocular uncorrected distance and near visual acuity of 20/25, respectively. At the last visit Spherical aberration and total higher aberration were higher than the corresponding preoperative levels (P<0.001); however, no significant difference was found in MTF, OSI, or Strehl ratio. Transient decreases in OSI and MTF mainly occurred in the nondominant eyes. There was no significant difference in optical quality between the dominant and nondominant eyes, except for spherical aberration and horizontal coma (P<0.05). The PresbyMAX monocular mode is safe and effective for presbyopia correction. It has little effect on optical quality, though short-term degraded optical quality occurred mainly in the bi-aspheric ablated eyes.

Short-time evaluation on intraocular scattering after implantable collamer lens implantation for correcting high myopia

BackgroundTo compare the intraocular scattering before and after implantation of implantable collamer lens (ICL) V4c for correction of high myopia in a short term.MethodsIn this study, 38 eyes of 19 patients who underwent the implantation of ICL V4c were followed up for 3 months. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), objective scattering index (OSI), modulation transfer function cutoff frequency (MTF cutoff), strehl ratio (S/R), OV100%, OV20% and OV9% were measured pre- and postoperatively. Meantime, the Pseudophakic Dysphotopsia Questionnaire (PDQ) was scored to evaluate the subjective satisfaction of intraocular scattering pre- and postoperatively.ResultsThe UCVA were − 0.02 ± 0.06, − 0.03 ± 0.07 and − 0.04 ± 0.07 logMAR at 1 week, 1 month and 3 months postoperatively which were significantly better than those preoperatively (P < 0.05). The BCVA were − 0.09 ± 0.09, − 0.09 ± 0.1 and − 0.1 ± 0.11 logMAR at 1 week, 1 month and 3 months after surgery, which were better than those before surgery significantly (t = 15.64, P < 0.05). The mean OSI were 2.37 ± 1.6, 1.63 ± 0.94, 1.5 ± 0.86 and 1.43 ± 1.05 preoperatively, 1 week, 1 month and 3 months postoperatively which was found significant difference (F = 12.92 P < 0.05). No significant differences were found in MTF cut off (F = 0.61, P = 0.62), S/R (F = 0.58, P = 0.36), OV100% (F = 0.966, P = 0.65), OV20% (F = 0.121, P = 0.96) and OV9% (F = 1.01, P = 0.30) between pre- and postoperatively. The PDQ results indicated that intraocular scattering reduced at 3 months after surgery significantly (P < 0.05).ConclusionsThe ICL V4c implantation for correcting high myopia induced less intraocular scattering and visual disorder than spectacle correction.

Optical Quality of Highly Myopic Eyes under Different Lighting Conditions and Other Relevant Parameters

ABSTRACT Purpose: To evaluate the optical quality of highly myopic eyes under light and dark conditions and correlate it with other relevant parameters. Materials and Methods: A cross-sectional, observational study was performed on 180 eyes of 90 highly myopic patients (29 males and 61 females; mean age: 27.833 ± 0.364 years [range: 18–45 years]). The modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scattering index (OSI), and predicted visual acuity (PVA; 100%, 20%, and 9%) under different lighting conditions were measured to evaluate the optical quality, which was correlated with probable relevant factors, including, axis length, spherical equivalent (SE), uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (BDVA), astigmatism, and corneal curvature. The relationship between these visual parameters and optical quality was analyzed using a generalized linear model. Results: The OSIs were 1.241 ± 0.068 and 1.515 ± 0.076; the MTF cutoff frequencies were 37.725 ± 0.559 and 30.238 ± 0.550 cpd; the Strehl ratios were 0.219 ± 0.004 and 0.175 ± 0.003; and the PVAs at 100%, 20%, and 9% were 1.257 ± 0.019 and 1.001 ± 0.018, 0.949 ± 0.017 and 0.719 ± 0.015, and 0.579 ± 0.011 and 0.439 ± 0.010, under bright and dark conditions respectively. The optical quality parameters were correlated with age, SE, BDVA, corneal astigmatism, and curvature to different degrees under different lighting conditions. Conclusions: The optical quality declined in highly myopic eyes under both bright and dark lighting conditions. SE, BDVA, corneal astigmatism, and curvature were correlated with optical quality to different degrees under different lighting conditions.

Optical Quality Assessed by Optical Quality Analysis System in Chinese Primary Open-Angle Glaucoma Patients and Its Correlations with Psychological Disturbances and Vision-Related Quality of Life

Purpose: To investigate if optical quality assessed by Optical Quality Analysis System (OQAS) is a new factor for psychological disturbance and vision-related quality of life (QoL) in Chinese patients with primary open-angle glaucoma (POAG). Methods: This is a cross-sectional study. OQAS, automated static perimetry, the Hospital Anxiety and Depression Scale (HADS) Questionnaire, and the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) were used to assess optical quality, visual field, psychological health, and QoL in 64 POAG patients. Correlation between the OQAS parameters and QoL or psychological health was analyzed by linear regression model. Results: OQAS parameters, the modulation transfer function cutoff frequency (MTF cutoff) and the mean OQAS values (mean OV) were significantly related to mean deviation (MD). Statistically significant correlation was also found between MTF cutoff, the mean OV, and QoL in more than half of the NEI VFQ-25 subscale scores and the composite. The correlation coefficients between OQAS parameters and QoL were similar to those between MD and QoL in most of the subscale scores. HADS-Depression and HADS-Anxiety scores significantly correlated with MD in the worse eye, the composite and 3 subscales of NEI VFQ-25, general health, social function, and mental health, but were not correlated with optical quality parameters measured by OQAS. Conclusions: OQAS-assessed optical quality is negatively related to MD and is a valid indicator for vision-related QoL, but not for psychological health in our study group. OQAS might be an alternative or supplement to perimeter in POAG patients.

Optical quality after posterior chamber Phakic implantation of an intraocular Lens with a central hole (V4c implantable Collamer Lens) under different lighting conditions

BackgroundThe current study compared optical quality before and after implantation of a posterior chamber phakic intraocular lens with a central hole [V4c implantable collamer lens (ICL)] under bright and dark lighting conditions by means of the Optical Quality Analysis System™ (OQAS; Visiometrics, Terrassa, Spain).MethodsThis prospective study involved 91 eyes of 46 consecutive high myopia patients (15 males and 31 females, average spherical equivalent − 10.50 ± 0.33D) undergoing implantation of a V4c ICL. The modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scattering index (OSI), and predicted visual acuities (PVAs; 100, 20, and 9%), under different lighting conditions, were measured before and 1 week, 1 month, and 3 months after surgery.ResultsAll optical parameters showed significant improvements, at all time points, under dark condition after surgery. We observed no significant changes in PVA 9% at 1 week (mean value 0.539, P = 0.12) or 1 month after surgery (mean value 0.573, P = 0.08) under bright condition; but all other postoperative parameters improved significantly. Comparing the two lighting conditions, the OSI decreased more under dark conditions at 1 week (P = 0.02), 1 month (P = 0.004), and 3 months (P = 0.002), but there was no significant difference in any other parameter. In addition, patients were divided into super high myopia (group S, spherical equivalent greater than − 10 D) and high myopia (group H, spherical equivalent from − 6 D to − 10 D), the group S improved significantly more than group H in all parameters, under both bright and dark conditions.ConclusionsV4c ICL implantation improved optical quality under both bright and dark lighting conditions, and had a better ability to reduce the extent of scattering in the dark. Furthermore, group S achieved greater improvement in visual quality, which should be considered by physicians before surgery.

Optical quality assessment in branch retinal vein occlusion after monthly intravitreal ranibizumab injection: a prospective, case-control study

ABSTRACT Purpose To evaluate optical quality and intraocular scattering using the Optical Quality Analysis System (OQAS) II in branch retinal vein occlusion (BRVO) and to investigate the influences of retinal changes on optical quality. Materials and methods Sixty-two patients with diagnosis of BRVO were enrolled in this prospective, case–control study. The control group consisted of the patients’ fellow eyes. Initial logMAR visual acuity, central macular thickness, and optical quality parameters including modulation transfer function cutoff frequency (MTF cut off), Strehl ratio (SR), objective scatter index (OSI) and OQAS values (OVs) at 100%, 20%, and 9% contrast levels were measured. Every BRVO-affected eye was treated with monthly intravitreal ranibizumab injection. We investigated the differences between clinical parameters of the BRVO-affected eye and those of the control eye and changes in those parameters on the basis of the clinical course of BRVO over 3 months. Results All the OQAS parameters measured except objective refraction error differed statistically significantly between the two groups. As macular thickness decreased and visual acuity improved, all the optical quality parameters except for objective refraction error and OV at 100% contrast gradually recovered with time after treatment but did not return to normal compared with the control eye. Only visual acuity was found to be significantly related to central macular thickness change (p = .027). Conclusions BRVO resulted in declined visual acuity and optical quality. It is suggested that the optical quality parameters are affected by the inner layers of the retina in BRVO.

Early outcomes of vision and objective visual quality analysis after cataract surgery with trifocal intraocular lens implantation.

To investigate the early outcomes of vision, objective visual quality and their correlation after cataract surgery with trifocal intraocular lens implantation. The visual examination and objective visual quality analysis using Optical Quality Analysis System (OQAS) at 1mo and 3mo, and defocus curve examination at 3mo were performed in 20 patients (27 eyes) after phacoemulsification combined with trifocal intraocular lens implantation surgery. The uncorrected distant (UD), intermediate and near visual acuity (VA) were significantly improved after surgery (P<0.001). UDVA at 1mo after the surgery was slightly better than that after 3mo (P=0.026). The defocus curve after 3mo indicated that the peak of distant vision was close to 0 logMAR, and UDVA was lower than 0.3 logMAR in the range of -1.5 D to -3.0 D. The modulation transfer function (MTF) cutoff frequency, strehl ratio (SR), Optical Quality Analysis System values (OVs), includes OV100, OV20 and OV9 after the surgery were significantly better than before surgery (P<0.001), but the objective scattering index (OSI) was significantly decreased (P<0.001). UDVA at 3mo after the surgery had correlations with MTF cutoff, OSI, OV100 and OV20 (r=-0.400, 0.431, -0.437, -0.411, P=0.039, 0.025, 0.023, 0.033). The uncorrected intermediate VA after 3mo of the surgery had correlations with OSI and OV100 (r=0.478, -0.411, P=0.012, 0.033). Trifocal intraocular lens implantation can provide good distant, intermediate and near VA, and the vision shows a well correlation with objective visual quality during early surgery.

Influence of angle kappa and angle alpha on visual quality after implantation of multifocal intraocular lenses

To assess the influence of angle kappa (κ) and angle alpha (α) on visual quality after multifocal intraocular lens (IOL) implantation. Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China. Prospective case series. Patients with cataract had phacoemulsification with TECNIS Symfony IOL implantation. The preoperative angle κ and angle α were measured using the iTrace device. Distance, intermediate, and near visual acuities were recorded 3months postoperatively. The Optical Quality Analyzing System was used to measure the objective scatter index (OSI), modulation transfer function (MTF) cutoff frequency, and Strehl ratio. A patient questionnaire was also administered. The study comprised 29 patients (57 eyes). Monocularly, the mean postoperative logarithm of the minimum angle of resolution (logMAR) uncorrected distance, intermediate, and near visual acuities were 0.03±0.09 (SD), 0.05±0.11, and 0.11±0.09, respectively. The mean postoperative logMAR corrected distance, distance-corrected intermediate, and distance-corrected near visual acuities were -0.01±0.05, 0.04±0.09, and 0.11±0.08, respectively. The mean OSI, MTF cutoff, and Strehl ratio were 1.27±0.84, 32.03±10.80 cycles per degree, and 0.17±0.05, respectively. The OSI (r=0.398, P=.005), MTF (r=-0.437, P=.002), and Strehl ratio (r=-0.419, P=.003) values were significantly correlated with angle κ. There was no correlation with angle α. Angle κ affected the objective visual quality multifocal after IOL implantation. The decision to implant a multifocal IOL should be carefully considered for patients with a large angle κ.

Optical Quality and Intraocular Scattering in the Diabetic Eye without Diabetic Retinopathy.

SIGNIFICANCEThis study suggests that despite having comparable best-corrected visual acuity and normal fundus appearance, objective measurements of optical quality showed that patients with diabetes but without overt retinopathy may have impaired visual function. Screening using the Optical Quality Analysis System might help identify those patients.PURPOSEVisual impairments are common in diabetes, but the status of the problem is unclear before the development of diabetic retinopathy. The aim of this pilot study was to investigate the optical quality and intraocular scattering in the diabetic eye without diabetic retinopathy.METHODSTwenty-seven patients with diabetes without diabetic retinopathy were enrolled. Twenty-seven age- and sex-matched healthy volunteers served as a control group. Optical quality parameters included modulation transfer function cutoff frequency, Strehl (two-dimensional) ratio, and Optical Quality Analysis System values at 100, 20, and 9 contrast levels. The objective scatter index was assessed using the Optical Quality Analysis System. Correlations were analyzed between the modulation transfer function cutoff, Strehl ratio, objective scatter index, and Optical Quality Analysis System value, and the age of the patient and the duration of diabetes mellitus.RESULTSThe diabetic group exhibited lower modulation transfer function cutoff, Strehl ratio, and Optical Quality Analysis System values at 100, 20, and 9% contrast levels and higher objective scatter index than did the controls (all, P < .01). There were no associations between the optical quality parameters and age or the duration of diabetes mellitus in the diabetic participants (all, P > .05). Moderate associations were found between all parameters obtained from the Optical Quality Analysis System and age in the control group (all, P < .01).CONCLUSIONSThis pilot study suggests that optical quality was reduced, and intraocular scattering increased in the diabetic eye without diabetic retinopathy compared with controls.

Objective evaluation of vision quality in pseudophakic patients with posterior capsular opacification using double-pass retinal imaging.

The purpose of this study was to objectively assess the optical vision quality of patients before and after Nd:YAG capsulotomy for posterior capsular opacification using a double-pass retinal imaging system. We retrospectively analyzed the data from 26 pseudophakic eyes with posterior capsular opacification that underwent Nd:YAG capsulotomy. The objective scatter indices, modulation transfer function cutoff frequencies, Strehl ratios, and logMAR corrected distance visual acuities were assessed before and after YAG capsulotomy with a double-pass retinal imaging system (OQAS II, Visiometrics, Spain). We also analyzed data from a subgroup of 10 patients with pre-YAG corrected distance visual acuity of 0.10 logMAR (20/25) or better. Vision quality indices improved in all 26 eyes, resulting in a statistically significant improvement in the corrected distance visual acuity (p=0.007), objective scatter index (p=0.001), modulation transfer function cutoff frequency (p=0.001), and Strehl ratio (p=0.020). The overall mean improvements included 0.12 ± 0.04 logMAR for corrected distance visual acuity, 2.84 ± 0.76 for objective scatter index, 12.29 ± 2.77 for modulation transfer function cutoff frequency, and 0.06 ± 0.03 for Strehl ratio. Our sub-analysis of 10 eyes with 0.10 logMAR (20/25) corrected distance visual acuity or better also showed a statistically significant improvement in the mean objective scatter index (0.76 ± 16; p=0.001), resulting in approximately 35% decrease in intraocular light scatter. The objective vision quality measurements as assessed by the double-pass retinal imaging system showed a significant improvement after YAG capsulotomy. This suggests that the objective scatter index improves after YAG capsulotomy, even in eyes with pre-YAG 0.10 logMAR (Snellen 20/25) corrected distance visual acuity or better.

Corneal Cap Thickness and Its Effect on Visual Acuity and Corneal Biomechanics in Eyes Undergoing Small Incision Lenticule Extraction.

Purpose To evaluate the effect of corneal cap thickness on visual acuity and corneal biomechanics in small incision lenticule extraction (SMILE) for the treatment of myopia. Methods Forty eyes of 20 patients undergoing SMILE for the treatment of myopia were enrolled in this prospective controlled study. The patients with 510 μm–560 μm central corneal thickness (CCT) and a refractive spherical equivalent of −3.00 D to −8.00 D were included. It was designed randomly to undergo SMILE with a 110 μm cap thickness in one eye and 150 μm cap thickness in the other. Ophthalmic examinations included best-corrected and uncorrected visual acuity (UCVA); refractive status, contrast sensitivity, and objective visual quality were evaluated at 2 h, 4 h, and 24 h postoperatively; while at 3 months after the procedure, corrected intraocular pressure (IOP), higher order aberrations (HOAs), and morphologic modifications of corneal architecture of both eyes were assessed. Results Compared with the 150 μm group, the incidence of OBL was significantly higher in the 110 μm cap thickness group (P=0.004), and UCVA, Strehl ratio (SR), objective scatter index (OSI), modulation transfer function (MTF) cutoff frequency, and photopic and scotopic contrast sensitivity at medium spatial frequency were all significantly better in 110 μm group at 2 h and 24 h postoperatively (P < 0.05). Corneal spherical aberration and corrected IOP by Corvis ST were significantly higher in the 110 μm group at 3 months postoperatively (P < 0.05). No statistically significant differences were found in manifest refraction, UCVA, SR, OSI, MTF cutoff, and mesopic and photopic contrast sensitivity at low frequency, photopic contrast sensitivity at high frequency, endothelial density, corneal coma, and total HOAs at 3 months after the procedure. No visual decline was found in the patients in this study. Conclusions Both 110 μm and 150 μm cap thickness in SMILE were safe and effective for treatment of myopia. A 110 μm cap thickness demonstrated better visual outcomes during early and late postoperative periods with higher corneal spherical aberration and corrected IOP at 3 months postoperatively. This trial is registered with ChiCTR-IOR-17013369.

Refractive outcomes and optical quality after implantation of posterior chamber phakic implantable collamer lens with a central hole (ICL V4c)

BackgroundTo investigate refractive outcomes and optical quality after implantation of posterior chamber phakic implantable collamer lens with a central hole (ICL V4c) to correct high myopia.MethodsSixty seven eyes of 38 patients who underwent ICL V4c implantation were enrolled. The mean preoperative spherical equivalent (SE) was − 12.44 ± 3.15 D (range: − 6.63 to − 20.50 D). The refractive outcomes and optical quality of the eyes at postoperative 1 and 3 months were evaluated and compared.ResultsAt 3 months postoperatively, the mean safety and efficacy indexes were 1.33 ± 0.22 and 1.14 ± 0.23, respectively. The mean SE was − 0.32 ± 0.52 D; no patient lost 1 or more lines of corrected distance visual acuity (CDVA), 13% remained unchanged, 45% gained 1 line and 42% gained 2 or more lines. The mean modulation transfer function cutoff frequency (MTFcutoff), Strehl in two dimensions ratio, and objective scatter index (OSI) were 38.20 ± 9.96 cycles per degree, 0.21 ± 0.06, and 1.00 ± 0.73, respectively. No significant difference was found in any of the above parameters (P > 0.05) between 1 and 3 months. The postoperative intraocular pressure (IOP) did not change when compared with preoperative values (P > 0.05).ConclusionsICL V4c implantation is a safe, effective, and stable solution for high myopia. Patients will acquire high and stable postoperative optical quality. ICL V4c implantation has little influence on IOP.

Comparison of optical quality after implantable collamer lens implantation and wavefront-guided laser in situ keratomileusis.

To compare the optical quality after implantation of implantable collamer lens (ICL) and wavefront-guided laser in situ keratomileusis (WG-LASIK). The study included 40 eyes of 22 patients with myopia who accepted ICL implantation and 40 eyes of 20 patients with myopia who received WG-LASIK. Before surgery and three months after surgery, the objective scattering index (OSI), the values of modulation transfer function (MTF) cutoff frequency, Strehl ratio, and the Optical Quality Analysis System (OQAS) values (OVs) were accessed. The higher order aberrations (HOAs) data including coma, trefoil, spherical, 2nd astigmatism and tetrafoil were also obtained. For patients with pupil size <6 mm, HOAs data were analyzed for 4 mm-pupil diameter. For patients with pupil size ≥6 mm, HOAs data were calculated for 6 mm-pupil diameter. Visual acuity, refraction, pupil size and intraocular pressures were also recorded. In both ICL and WG-LASIK group, significant improvements in visual acuities were found postoperatively, with a significant reduction in spherical equivalent (P< 0.001). After the ICL implantation, the OSI decreased slightly from 2.34±1.92 to 2.24±1.18 with no statistical significance (P=0.62). While in WG-LASIK group, the OSI significantly increased from 0.68±0.43 preoperatively to 0.91±0.53 postoperatively (Wilcoxon signed ranks test, P=0.000). None of the mean MTF cutoff frequency, Strehl ratio, OVs showed statistically significant changes in both ICL and WG-LASIK groups. In the ICL group, there were no statistical differences in the total HOAs for either 4 mm-pupil or 6 mm-pupil. In the WG-LASIK group, the HOA parameters increased significantly at 4 mm-pupil. The total ocular HOAs, coma, spherical and 2nd astigmatism were 0.12±0.06, 0.06±0.03, 0.00±0.03, 0.02±0.01, respectively. After the operation, these values were increased into 0.16±0.07, 0.08±0.05, -0.04±0.04, 0.03±0.01 respectively (Wilcoxon signed ranks test, all P<0.05). At 6 mm-pupil, the induction of total HOAs was not statistically significant in the WG-LASIK group. ICL implantation has a less disturbance to optical quality than WG-LASIK. The OQAS is a valuable complementary measurement to the wavefront aberrometers in evaluating the optical quality.

Visual quality assessment after presbyopic laser in-situ keratomileusis.

To assess visual quality after presbyopia correction using an aspheric ablation profile and a micro-monovision protocol. This is a retrospective interventional study. Fifty-four eyes of 27 patients (mean age, 50.2±7.5y) who underwent presbyopia correction with an aspheric micro-monovision protocol were enrolled. The values of modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scattering index (OSI) and accommodation range were quantitatively assessed using the HD analyzer. Preoperative and postoperative contrast sensitivity (CS) at far (2.5 m) and near (40 cm) distance and higher-order aberrations (HOAs) were analyzed. Subjective visual satisfaction was evaluated by self-reported questionnaire regarding optical visual symptoms. One year after presbyopia correction, no significant differences were found in the MTF cutoff frequency, Strehl ratio and OSI, however, the HD analyzer accommodation range significantly differed postoperatively (P=0.004). Postoperative CS at 12 and 18 cpd at near showed statistically significant improvement (P=0.020 and 0.008, respectively). Visual performance by self-reported questionnaire revealed satisfactory results in terms of subjective visual quality improvement. Objective optical quality parameters show good visual outcomes. Subjective visual quality assessed by self-reported questionnaire in the presbyopia correction group show satisfactory results.

Cap morphology after small-incision lenticule extraction and its effects on intraocular scattering.

To investigate cap morphology after small-incision lenticule extraction (SMILE) and its effects on intraocular scattering. Sixty-five eyes of 33 patients undergoing SMILE were enrolled. In addition to regular evaluation, Fourier-domain optical coherence tomography was used to investigate cap thickness at 1d, 1wk, 1 and 3mo postoperatively. The optical quality including modulation transfer function cutoff frequency, Strehl ratio, Optical Quality Analysis System (OQAS) values, and objective scattering index (OSI), were evaluated using OQAS™. Cap thickness decreased from 1d to 1wk (P<0.001), but remained higher than intended thickness of 120 µm after 3mo (P<0.001). Cap thickness in central area was thinner than that of in the paracentral and peripheral areas (P<0.0001). Total number of microdistortions decreased from 1d to 3mo (P<0.0001). Pearson analysis revealed a weak correlation between OSI and standard deviation of cap thickness at 1d and 1mo, as well as between range of cap thickness and OSI at 1mo. No correlation was found between microdistortion and OSI, but a negative correlation existed between microdistortion and range at 1d and 1moafter surgery. The corneal cap tends to be more accurate and regular with time lapse. Better cap morphology tends to contribute less intraocular scattering in the eyes undergoing SMILE.

Visual outcomes after balanced salt solution infiltration during lenticule separation in small-incision lenticule extraction for myopic astigmatism.

To evaluate the refractive outcomes of balanced salt solution infiltration during small-incision lenticule extraction (SMILE).This randomized prospective study enrolled 52 patients (104 eyes) with myopic astigmatism. Patients underwent SMILE to correct the myopic astigmatism in Daping Hospital of the Third Military Medical University between January and July 2013. One eye of each patient received traditional SMILE (control group) and the other received a modified SMILE procedure (liquid infiltration group). The corrected distance visual acuity (CDVA), postoperative uncorrected distance visual acuity (UDVA), refraction, wavefront aberration, intraocular pressure (IOP), modulation transfer function (MTF) cut-off frequency, and objective scattering index (OSI) were evaluated.UDVA in the liquid infiltration group was significantly higher than that in the control group at 1 day postoperatively, but not at 1 month after surgery. Moreover, OSI and MTF cut-off frequency in the liquid infiltration group were higher than those in the control group at early follow-up. However, no significant intergroup difference was observed in the OSI and MTF cut-off frequency at 3 months after surgery. In addition, the predictability was better in the liquid infiltration group than in the control group. The changes of horizontal coma in the liquid infiltration group were lesser than those in the control group. However, no intergroup difference was observed in the reduction of IOP at 1 month after surgery.The modified SMILE procedure results in better visual outcomes than did the traditional SMILE procedure when used for treating myopic astigmatism.

Effects of aging on optical quality and visual function

BackgroundWe assessed the effects of aging on visual function and optical quality in a healthy adult population and provide reference values for different age ranges.MethodsWe conducted a prospective study with 198 healthy volunteers from 31 to 70 years of age. The visual acuity (VA) and contrast sensitivity (CS) at 3, 6, 12 and 18 cycles per degree (cpd) frequencies were assessed, together with values of optical quality and intraocular scattering obtained with a double‐pass system (Optical Quality Analysis System – OQAS), specifically the modulation transfer function cutoff frequency (MTFcutoff), the Strehl ratio, the OQAS values (OV) at contrasts of 100, 20 and nine per cent and the objective scatter index (OSI). We studied the change of these variables with age and obtained standard values for optical quality and intraocular scattering parameters for four age groups: 31 to 40, 41 to 50, 51 to 60 and 61 to 70 years.ResultsWe found significant correlations between age and all variables analysed and significant differences among the age groups considered except for CS (3 cpd) (p = 0.067). Ageing particularly affected low‐contrast parameters, such as the OV nine per cent and the OSI, which decreased to 37 and 50 per cent of their original values, respectively. The OSI was found to provide high sensitivity and specificity values, when healthy and caratactous eyes were considered. The results suggest that optical deficits are compensated until 50 years of age with sensory and perceptual factors, as smaller changes were found for visual function than for objective measurements of optical quality and intraocular scattering.ConclusionsMeasures of optical quality assessed by subjective psychophysical and objective techniques varied differently with age. Values obtained for each age group can be used to determine normal limits of optical quality and intraocular scattering for diagnosis of ocular conditions.

Double-pass technique and compensation-comparison method in eyes with cataract

To clinically assess the objective scatter index (OSI) obtained from double-pass images and the log(s) parameter measured with the direct compensation-comparison psychophysical technique in eyes with cataract. Ophthalmology Service, Terrassa Hospital, Barcelona, Spain. Prospective observational case series. The analysis comprised eyes diagnosed with nuclear, cortical, or posterior subcapsular cataracts and healthy eyes (control group). Patient examinations included assessment of the manifest subjective refraction, corrected distance visual acuity, contrast sensitivity, and cataract grade using the Lens Opacities Classification System III (LOCS III) score. The protocol also included the straylight (log[s]) measured by the C-Quant device, measurement of the objective optical quality (Strehl ratio and modulation transfer function cutoff frequency), and the OSI (HD Analyzer). Significant correlations with LOCS III classification were found in terms of log(s) and OSI, although they were slightly stronger with OSI for all cataract types, which could be attributable to higher-order aberrations. The OSI and log(s) shared approximately 44% of the scattering estimation and to coincide on the visual function decline with scattering for the 3 cataract types evaluated. Limits to discriminate between healthy and cataractous eyes and sensitivity and specificity values were 1.15 (sensitivity 91%, specificity 100%) for log(s) and 1.18 (sensitivity 89%, specificity 100%) for OSI (P<.05). Both instruments provide complementary information to diagnose cataracts and follow patients. Although backscattered light from deeper retinal layers can have an effect on OSI, the double-pass image provides information to grade different types of cataract when assessing cataractous eyes for treatment. None of the authors has a financial or proprietary interest in any material or method mentioned.

Optical quality and visual performance after cataract surgery with biaxial microincision intraocular lens implantation

To evaluate the time course of the optical quality and visual performance with a microincision monofocal intraocular lens (Incise). Hospital Torrecárdenas, Almería, Spain. Prospective study. The visual and refractive outcomes were evaluated in eyes with the microincision IOL preoperatively and 1, 3, and 6months postoperatively. The modulation transfer function (MTF) cutoff frequency, Strehl ratio, and objective scatter index (OSI) were used to measure optical quality. The contrast sensitivity function (CSF) and the visual disturbance index characterized visual performance. In the 32 study eyes, the mean values preoperatively and 6months postoperatively, respectively, were MTF cutoff frequency (11.40 cycles per degree [cpd]±8.39 [SD] and 23.33±11.68 cpd; P<.001), Strehl ratio (0.078±0.32 and 0.15±0.07; P<.05), and OSI (7.44±3.25 and 1.57±0.26; P<.001). At each spatial frequency, the CSF significantly differed between preoperatively and postoperatively (P<.001). The mean visual disturbance index changed from 0.70±0.28 to 0.31±0.17 (P<.001). For all parameters studied, statistically significant differences were found between the preoperative and postoperatively values, with no differences between the results 1, 3, and 6months after surgery (P>.05). Biaxial microincision cataract surgery provided optimum clinical outcomes. The optical quality and visual performance improved significantly 1month after surgery, with the results remaining stable at 6months. The postoperative visual function was similar to that in subjects of the same age with healthy eyes. None of the authors has a financial or proprietary interest in any material or method mentioned.

Objective assessment of comprehensive optical quality among adults at different ages

To objectively assess and compare comprehensive optical quality among adults at different ages. In this cross-sectional study, there were 432 subjects (432 eyes) aged from 20 to 70 years with best corrected visual acuity (BCVA) better than 4.9. If both eyes of a subject had equal BCVA, one eye was selected randomly. Otherwise, the eye with better BCVA was chosen. The patients were divided into 5 groups at an age interval of 10 years. The optical quality analysis system Ⅱ (OQASⅡ) was used to measure the following optical quality parameters: the modulation transfer function cutoff frequency (MTFcutoff), the Strehl ratio, three OQAS values (OV100%, OV20%, and OV9%), and the objective scatter index (OSI). Each optical quality parameter was compared among different groups by One-way ANOVA. In the groups of 20-29 years, 30-39 years, 40-49 years, 50-59 years, and 60-69 years, the MTFcutoff was (43.91±7.43), (40.93±9.92), (37.16±9.04), (36.69±7.87), and (28.52±8.31) cpd, respectively; the Strehl ratio was 0.26±0.06, 0.24±0.06, 0.20±0.05, 0.20±0.04, and 0.16±0.04, respectively; the OV100% was 1.47±0.24, 1.36±0.33, 1.24±0.30, 1.22±0.26, and 0.96±0.28, respectively; the OV20% was 1.51±0.33, 1.40±0.38, 1.22±0.36, 1.20±0.28, and 0.91±0.32, respectively; the OV9% was 1.14±0.26, 1.41±0.40, 1.20± 0.37, 1.18±0.28, and 0.89±0.28, respectively; the OSI was 0.42±0.24, 0.53±0.32, 0.54±0.34, 0.54±0.26, and 1.06±0.56, respectively. There were significant differences in the mean values of MTFcutoff, Strehl ratio, OV100%, and OV20% among groups (P<0.05), except for the groups of 40-49 years and 50-59 years (P>0.05). The OV9% was significantly different among groups (P<0.05), except for the groups of 20-29 years, 40-49 years, and 50-59 years (P>0.19). The OSI was also significantly different among groups (P<0.05), except for the groups of 30-39 years, 40-49 years, and 50-59 years (P>0.70). The comprehensive optical quality in the young healthy population is better than the old, except for a plateau in the middle-aged population.