Modulation Transfer Function Cutoff Frequency Research Articles

Comparatively analysing the postoperative optical performance of different intraocular lenses: a prospective observational study

BackgroundPostoperative performance, including best corrected distance visual acuity (BCDVA) and optical metrics (from the OQAS and iTrace devices), was compared among 4 different intraocular lenses (IOLs).MethodsThis prospective observational study included 104 eyes from 104 subjects who underwent cataract surgery combined with implantation of 4 different IOLs: monofocal (Mon) IOLs, segmental refractive (SegRef) IOLs, diffractive (Dif) IOLs and extended depth of focus (EDoF) IOLs. Postoperative BCDVA and optical metrics were collected at the 6th month. The OQAS optical metrics included the objective scattering index (OSI), Strehl ratio (SR), modulation transfer function (MTF) cut-off frequency, and predicted visual acuity (PVA); the iTrace optical metrics included blur/double vision, glare/halo, starburst, mixed focus, night myopia, and night hyperopia.ResultsThere was no significant difference in BCDVA among the 4 groups (P = 0.059; power = 70.3%). Differences were observed in all OQAS optical metrics among the groups (all P < 0.001). Overall, Mon IOLs and EDoF IOLs exhibited better performance than Dif IOLs and SegRef IOLs. Starburst was the only iTrace optical metric that differed among the groups (P < 0.001): SegRef IOLs caused more starbursts than Mon IOLs (P = 0.001), Dif IOLs (P = 0.006) and EDoF IOLs (P < 0.001). Spearman rank correlation analysis was used to determine the relationships among the iTrace optical metrics, OQAS optical metrics and BCDVA: starburst was negatively correlated with BCDVA, PVA at contrasts of 100% and 20%, OSI, and MTF cut-off frequency (all P ≤ 0.001); mixed focus was positively correlated with BCDVA, PVA at contrasts of 100% and 20%, OSI, and MTF cut-off frequency (all P ≤ 0.001).ConclusionsPostoperative BCDVA and optical metrics varied among the different IOLs, which should be taken into account in the selection and management of IOLs for cataract patients.Trial registrationThis study was approved by the First Affiliated Hospital of Guangzhou Medical University Ethical Review Board (No. 50 2022).

The impact of dry eye disease on retinal image quality in children

Background and ObjectivesDry eye disease (DED) is increasingly prevalent, resultinginhigher morbidityamong children. This study evaluates the impact of DED severity on visual quality using double-pass technology, focusing on dynamic observation of the ocular light scatter in pediatric DED cases. MethodIn this non-interventional, cross-sectional study, a mild DED group (37 cases, 37 eyes), a moderate DED group (40 cases, 40 eyes), and a control group of healthy children (35 cases, 35 eyes) were examined. Measurements included the Schirmer I test, tear film break-up time (BUT), and vision-related quality of life assessments using the Modified Ocular Surface Disease Index (OSDI) questionnaires. Participants underwent visual quality analysis using double-pass technology, which measured the modulation transfer function cut-off frequency value (MTF cutoff), Strehl ratio (SR), objective scatter index (OSI), and OQAS-II value (OQAS-II value OV100%, OQAS-II value OV 20%, and OQAS-II value OV 9%) under natural conditions. Additionally, dynamic changes in OSI post-blinking, Tear film mean-OSI (TFM-OSI), and the corresponding standard deviation OSI (SD-OSI) were recorded. ResultsStatistically significant differences were observed among the groups in modulation transfer function cutoff, Strehl ratio, OSI, OQAS-II value OV 100 %, OQAs-II value OV 20 %, OQAs-II value OV 9 %, tear film mean OSI, and standard deviation OSI (P < 0.05). As DED severity increased, tear film mean OSI significantly rose, while modulation transfer function cutoff, strehl ratio, OQAS-II value OV 100 %, OQAS-II value OV 20 %, OQAS-II value OV 9 % notably declined. All optical quality parameters were correlated with BUT, with no association observed with age, sex, or Schirmer I test. ConclusionDual-channel technology objectively assesses visual quality in pediatric DED, demonstrating that tear film scattering significantly affects retinal imaging and visual quality in children with DED.

Therapeutic effect of a new implantation method of rotationally asymmetric multifocal intraocular lenses on visual quality.

To assess the visual quality after implantation of a rotationally asymmetric multifocal intraocular lens (IOL) using a new method according to the angle kappa. Qingdao Eye Hospital, Qingdao, China. Prospective case series. Patients with the implantation of SBL-3 IOLs for age-related cataract from September to December 2019 had the distance-horizontal zone of the IOL placed at the center of the optic axis using the Callisto Eye System. Postoperative visual acuities and defocus curves were recorded. Modulation transfer function cutoff frequency, Strehl ratio, and objective scatter index were measured using the Optical Quality Analysis System. The decentration and tilt of IOLs were analyzed by iTrace aberrometry and anterior segment optical coherence tomography. A questionnaire of patient satisfaction was also collected. Thirty patients (60 eyes) were involved, with a balanced sex ratio. Their average age was 56.04 ± 10.83 years. The average angle kappa distance was 0.23 ± 0.121 mm. At 3 months after surgery, the mean uncorrected and corrected distance visual acuities were 0.01 ± 0.07 logMAR and 0.01 ± 0.06 logMAR. The uncorrected intermediate and near visual acuities were 0.09 ± 0.11 logMAR and 0.09 ± 0.11 logMAR. The mean horizontal and vertical tilts of IOLs were 0.67 ± 0.52 degrees and 0.47 ± 0.32 degrees. The mean decentration of IOLs was 0.17 ± 0.08 mm. Most patients were satisfied with their distance, intermediate, and near vision. There was mild glare in 58.3% of the eyes. Locating the center of the optic axis in the distance-horizontal zone during the implantation of SBL-3 IOLs could provide satisfactory visual acuity and quality.

Higher-order aberrations and visual quality after incision lenticule extraction surgery with intraoperative angle kappa adjustments between small and large kappa patients: A 2-year follow-up.

To evaluate the postoperative visual outcomes, that is, corneal higher-order aberrations (HOAs) and visual quality, of patients with an angle kappa greater than 0.30 mm who underwent angle kappa adjustment during small-incision lenticule extraction (SMILE) 2 years after surgery compared to eyes with an angle kappa less than 0.30 mm. This was a retrospective study and included 12 patients from October 2019 to December 2019 who underwent the SMILE procedure for correction of myopia and myopic astigmatism and had one eye with a large kappa angle and another eye with a small kappa angle. Twenty-four months after surgery, an optical quality analysis system (OQAS II; Visiometrics, Terrassa, Spain) was used to measure the modulation transfer function cutoff frequency (MTFcutoff), Strehl2D ratio, and objective scatter index (OSI). HOAs were measured with a Tracey iTrace Visual Function Analyzer (Tracey version 6.1.0; Tracey Technologies, Houston, TX, USA). Assessment of subjective visual quality was achieved using the quality of vision (QOV) questionnaire. At 24 months postoperatively, the mean spherical equivalent (SE) refraction was - 0.32 ± 0.40 and - 0.31 ± 0.35 in the S-kappa group (kappa <0.3 mm) and the L-kappa group (kappa ≥0.3 mm), respectively (P > 0.05). The mean OSI was 0.73 ± 0.32 and 0.81 ± 0.47, respectively (P > 0.05). There was no significant difference in MTFcutoff and Strehl2D ratio between the two groups (P > 0.05). Total HOA, coma, spherical, trefoil, and secondary astigmatism were not significantly different (P > 0.05) between the two groups. Adjustment of angle kappa during SMILE helps reduce the decentration, results in less HOAs, and promotes visual quality. It provides a reliable method to optimize the treatment concentration in SMILE.

Postoperative efficacy, safety, predictability, and visual quality of implantable collamer lens implantation versus small incision lenticule extraction in myopic eyes: a Meta-analysis.

To compare the postoperative efficacy, safety, predictability, and visual quality of implantable collamer lens (ICL) implantation versus small incision lenticule extraction (SMILE) in myopia eyes. PubMed, EMBASE, Web of Science, Cochrane Library and several Chinese databases were searched at May 2021 to select relevant studies in comparison of clinical outcomes between ICL implantation and SMILE for myopia. The primary outcomes were efficacy, safety, and predictability. And the secondary outcomes were postoperative higher-order ocular aberrations (HOAs), modulation transfer function cutoff frequency (MTF), objective scatter index (OSI), contrast sensitivity and a quality of vision (QoV) questionnaire. A total of 1036 eyes from 10 studies, of which 503 eyes underwent ICL implantation and 533 eyes underwent SMILE, were enrolled in this Meta-analysis. Pooled results revealed that ICL group had a better safety index and post-corrected distance visual acuity (CDVA) (P=0.007, <0.00001, respectively), and a lower percentage of eyes with a postoperative CDVA lost 1 line (P=0.007) than the SMILE group. No significant differences were found in comparison of the other primary outcomes. In the long-term follow-up (>6mo), ICL group had a lower total HOA, coma, and spherical aberration than SMILE group (P=0.003, <0.00001, 0.04). Yet higher trefoil was found in ICL group at 6mo after surgery (P=0.003). Additionally, ICL group also had a higher MTF value (P=0.02), and a higher contrast sensitivity score for spatial frequencies of 1.5, 6, and 12 cpds (P=0.02, 0.005, 0.02, respectively). And it also had a lower score of bothersome in QoV questionnaire than SMILE group (P=0.003). ICL implantation and SMILE have similar and comparable outcomes in term of the efficacy and predictability for correcting high myopia. However, ICL group is relatively safer and also has better visual quality in comparison of SMILE group.

Effect of larger corneal spherical aberration in improving the near visual acuity of eyes implanted with the TECNIS Symfony.

To explore the effect of corneal spherical aberration on the visual acuity and visual quality of eyes implanted with the TECNIS Symfony intraocular lens (IOL). A total of 43 patients with age-related cataract (60 eyes) undergoing phacoemulsification and TECNIS Symfony IOL implantation were enrolled in this study. The uncorrected distance (UDVA), intermediate (UIVA), near visual acuity (UNVA), corrected distance visual acuity (CDVA), contrast sensitivity, and ocular spherical aberration were recorded 3 months after surgery. Preoperative and postoperative corneal spherical aberration were also measured using the iTrace device. Objective scattering index (OSI), modulation transfer function cut-off frequency (MTF cut-off), and Strehl ratio (SR) were measured by the Optical Quality Analyzing System. Catquest-9SF questionnaire were applied too. Spearman's correlation analysis was used to evaluate the relationship between spherical aberration and visual quality parameters. Patients were satisfied with their postoperatively visual quality. And the postoperative logMAR UDVA, UIVA, UNVA, and CDVA was 0.05 ± 0.07, 0.04 ± 0.06, 0.15 ± 0.07, and 0.03 ± 0.05, respectively. The mean preoperative corneal spherical aberration was 0.24 ± 0.10 μm, which is the only factor influencing postoperatively UNVA, and it was negatively correlated with UNVA and glare contrast sensitivity under 18 cpd (cycle/degree, cpd) spatial frequency (r = -0.403, -0.300, -0.360; all P < 0.05). Additionally, the greater the residual spherical aberration of the cornea, the better the near vision after operation. The mean postoperative ocular spherical aberration was -0.03 ± 0.07 μm, it was not correlated with visual acuity, contrast sensitivity, and visual quality (all P > 0.05). Preoperative positive spherical aberration can benefit near vision while decrease contrast sensitivities at high spatial frequencies when implanted with the TECNIS Symfony IOL.

Long-term observation on safety and visual quality of implantable collamer lens V4c implantation for myopia correction: a 5-year follow-up.

To elucidate the safety and visual quality of implantable collamer lens with central hole (ICL V4c) implantation for correcting moderate and high myopia for at least 5y. This retrospective study was conducted on 58 patients (114 eyes) who were followed up for at least 5y after ICL V4c implantation. The observation was done before and on 1d, 1mo, 1 and 5y or more after the surgical procedure. The visual acuity, subjective refraction, intraocular pressure, vault, axial length, central hole position, pupil diameter, visual quality, and adverse events were analyzed. The visual quality includes aberration, the modulation transfer function cutoff frequency (MTF cutoff), objective scattering index (OSI), Stroller's ratio (SR), and visual quality questionnaire. The average follow-up period was 69.25±3.80mo (range 60-82mo) and the preoperative spherical equivalent (SE) was -8.66±1.97 D. At 5y after operation, the safety index was 1.01±0.02 and the efficacy index was 0.99±0.42 and SE was -0.65±0.63 D. The 59.6% of the eyes achieved an uncorrected distance visual acuity of 20/20, 76.3% of the eyes had SE within ±1.0 D at the last visit. The axial length increased by 0.29±0.71 mm 5y after the surgery (t=-3.843, P<0.001). The mean vault at the last follow-up was 510.59±245.61 µm. The central hole was on the temporal side in 80 eyes (84.2%). The visual quality questionnaire showed that 98.2% patients were satisfied with the surgical procedure. Adverse events occurred in 4 eyes (3.5%), including the posttraumatic toric ICL rotation (2 eyes), iris incarceration (1 eye), and posttraumatic ICL displacement (1 eye) at the last follow-up. Long-term ICL V4c implantation is safe, effective, and stable for correcting moderate and to high myopia, and the visual quality with patients is excellent and satisfactory, but the progression of axial length still needs attention after surgery.

Evaluation value of subjective visual quality examination on surgical indications of the early cataracts based on objective scatter index values.

To evaluate the subjective visual functions of early cataracts patients and assess their surgical indications. Eyes were separated into a control group (Group A without cataract) and two early cataracts groups (Group B with 2.0 ≤ OSI < 3.0 and Group C with 3.0 ≤ OSI < 4.0). The objective scatter index (OSI), modulation transfer function cut-off frequency (MTF cut-off), and Strehl ratio (SR) values were applied to measure objective visual functions. The contrast sensitivity (CS) and scores of the questionnaires (QOL and VF-14) characterized subjective visual functions. Above visual functions were compared among three groups. Postoperative visual functions in Group B and C were analyzed to assess the outcome of surgery. Ninety two subjects (126 eyes) were included in the study. All objective visual function in Group B were significantly better than Group C (all P < 0.01), but worse than Group A (all P < 0.01). Except for 1.5 c/d CS, subjective visual function in Group A were significantly better than Group B and C (all P < 0.05), but there was no significant differences between Group B and C. As for eyes that underwent surgery in Group B and C, all visual functions significantly improved after surgery (P < 0.05), except for 1.5 c/d CS in Group C. There were no significant differences among the three groups after surgery. The subjective visual function can be impaired in early cataracts patients with OSI < 3.0, whose objective visual functions were statistically better than patients with OSI ≥ 3.0. These patients can benefit equally from surgery as patients with OSI ≥ 3.0. Subjective visual functions can be used as surgical indications for these patients.

Comparison of Visual Outcomes and Optical Quality of Femtosecond Laser-Assisted SMILE and Visian Implantable Collamer Lens (ICL V4c) Implantation for Moderate to High Myopia: A Meta-analysis.

To compare visual outcomes and optical quality of femtosecond laser-assisted small incision lenticule extraction (SMILE) and Visian Implantable Collamer Lens (ICL V4c; STAAR Surgical) implantation for moderate to high myopia. For this systematic review and meta-analysis, the Cochrane, PubMed, Embase, and Chinese databases (Wan-fang data and CNKI) were comprehensively searched to identify studies comparing SMILE and ICL V4c implantation. Data of interest were extracted and analyzed by Stata V.16.0 software (StataCorp). The weighted mean differences and their 95% confidence intervals were used to assess the strength of the association. Twelve studies incorporating 1,390 eyes of 822 patients were included. The analysis revealed ICL V4c implantation had a significantly higher safety index and lower high order aberrations, coma, and spherical aberration than SMILE in treating moderate to high myopia (P < .05). Subgroup analysis revealed such differences were more prominent in patients with high myopia who had shorter follow-up duration. When follow-up was longer than 6 months, the differences in safety index and total HOAs became nonsignificant (P > .05). The two procedures had no difference in efficacy index, postoperative visual acuity, spherical equivalent, trefoil, Objective Scatter Index, or modulation transfer function cut-off frequency (P > .05). Both SMILE and ICL V4c implantation were safe and efficient for moderate to high myopia. Compared with SMILE, ICL V4c implantation might provide better postoperative visual quality in patients with high myopia in the early postoperative period. [J Refract Surg. 2022;38(6):332-338.].

Visual Function in Children With Posterior Lens Opacities Before and After Surgery

To evaluate the visual function before and after cataract surgery in children with congenital posterior lens opacities as well as the factors associated with a good visual outcome. Perspective case-series study. Pediatric patients with posterior lens opacities who underwent cataract surgery were recruited in this study. The cataract type, location, area of opacities, and strabismus were examined perioperatively. Moreover, visual acuity, modulation transfer function (MTF), ocular aberrations, and stereopsis were measured before and after cataract surgery. Sixty-nine eyes of 63 patients were studied. The mean age of patients at surgery was 6.5 ± 2.9 years. Visual function including corrected distance visual acuity (CDVA), MTF cutoff frequency, and ocular aberrations were significantly affected in eyes with posterior lens opacities. Postoperatively, CDVA was significantly improved from 0.81 ± 0.53 logMAR to 0.40 ± 0.40 logarithm of the minimum angle of resolution (logMAR) (P < .001). Thirty-nine patients (56.5%) achieved a final VA of 20/40 or better. Moreover, MTF cutoff values were significantly improved, and total ocular aberrations were decreased after cataract removal (both P < .001). The stereopsis was also improved postoperatively (P < .001). The multivariate analysis of the risk factors for postoperative CDVA showed that worse preoperative CDVA, larger size of lens opacities, and mean keratometry were the risk factors (all P < .05). Visual function can be significantly decreased in children with posterior lens opacities, and surgery was effective in improving visual function. Patients with a CDVA of 0.52 logMAR or better, a size of lens opacity <6.5 mm2 and smaller mean keratometry had a greater CDVA postoperatively.

A meta-analysis of visual outcomes and optical quality after small incision lenticule extraction versus implantable collamer lens for myopia.

To evaluate possible differences in visual outcome and optical quality when small incision lenticule extraction (SMILE) versus implantable collamer lens (ICL) is used to correct myopia. PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched up to August 2021 to identify relevant studies. The PRISMA guidelines were followed. Primary outcomes were postoperative efficacy, safety, and predictability at the end of follow-up. Secondary outcomes were changes in modulation transfer function cutoff frequency (MTF cut-off), objective scatter index (OSI) values, total higher-order aberrations (HOAs), spherical aberrations, and coma aberrations. Seven studies with a total of 1296 eyes (SMILE: 731 eyes; TECXL: 565 eyes) were included. The ICL group had a better MTF cut-off (P = 0.007) and less change in the proportion of HOAs (P < 0.001), spherical aberrations (P = 0.009), and coma (P = 0.006) than the SMILE group. For the other outcomes, there were no statistically significant differences. SMILE and ICL implantation are comparable in efficacy, safety, and predictability for correcting myopia. Larger studies with longer follow-up times are warranted to provide a better understanding of the benefits of SMILE and ICL implantation.

Refractive Lens Exchange Surgery in Early-Onset High Myopia Patients With Partial Cataract.

PurposeBy reporting clinical characteristics and retinal image quality before and after refractive lens replacement surgery in early-onset high myopia (eoHM) patients presenting with partial cataract, we emphasized the need for an objective way to grade the severity of partial cataracts.MethodsThis retrospective, consecutive case series included six Chinese patients (nine eyes). Analysis of previous medical records, visual acuity, optometry, retinal image quality, and axial length (AXL) before surgery and after surgery was performed.ResultsFive females and one male (nine eyes) with a mean (± SD) age of 11.6 ± 7.9 years (range: 4–25 years) were included in this study. The preoperative spherical power ranged from −7.5 to −42 D. The mean follow-up time was 36 months (range: 24–48 months). Phacoemulsification was followed by in-the-bag implantation of intraocular lens. For patients who were under 6 years old, posterior capsulotomy + anterior vitrectomy were performed simultaneously. All surgeries were uneventful and no postoperative complications occurred during the entire follow-up period. All patients’ uncorrected visual acuity improved by ≥2 lines postoperatively(Snellen acuity). LogMAR best-corrected visual acuity was improved at 24-month (P = 0.042) and endpoint (P = 0.046) follow-ups. Modulation transfer function cutoff frequency (MTFcutoff) and objective scatter index (OSI) was significantly improved at 12-month (P = 0.025, P = 0.038), 24-month (P = 0.005, P = 0.007) and endpoint (P = 0.005, P = 0.008) follow-ups. Postoperative AXL remained stable during 2–4 year follow-ups (P > 0.05).ConclusionRefractive lens replacement surgery is safe and effective for improving functional vision in eoHM patients presenting with partial cataract. Retinal image quality could provide a useful and objective way to facilitate partial cataract severity evaluation and surgery decision making.

Effects of low-concentration atropine eye drops on the optical quality of the eyes in myopic children.

Purpose:The present study was performed to compare the optical quality of the eyes of myopic children before and after treatment with atropine eye drops of different concentrations.Methods:In the study population of 71 patients (131 eyes), 34 patients (63 eyes) were given 0.01% atropine eye drops and 37 patients (68 eyes) were given 0.05% atropine eye drops. 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 after two weeks of atropine treatment.Results:After using 0.05% atropine eye drops for two weeks, the Strehl ratio decreased from 0.27 ± 0.07 to 0.23 ± 0.07 (P = 0.0026), PVA 20% decreased from 1.15 ± 0.32 to 1.03 ± 0.36 (P = 0.0344), and PVA 9% decreased from 0.74 ± 0.23 to 0.64 ± 0.23 (P = 0.0073). The OSI was significantly higher after using 0.05% than 0.01% atropine eye drops (P = 0.0396), while both the Strehl ratio and PVA 20% were lower after using 0.05% than 0.01% atropine eye drops (P = 0.0087 and P = 0.0492, respectively).Conclusion:The children’s optical quality did not change significantly after using 0.01% atropine eye drops, whereas it decreased after using 0.05% atropine eye drops.

Five-Year Follow-Up of Visual Outcomes and Optical Quality After Small Incision Lenticule Extraction for Moderate and High Myopia.

IntroductionThis study investigated the long-term visual and optical quality changes after small incision lenticule extraction (SMILE) for the correction of moderate to high myopia.MethodsForty-one eyes of 41 patients with a mean spherical equivalent (SE) of − 6.74 ± 1.45 D undergoing SMILE were enrolled. Preoperative and 1-month, 3-month, 1-year and 5-year postoperative follow-up examinations were performed including visual acuity, manifest refraction, corneal aberrations and contrast sensitivity. An optical quality analysis system was used to measure objective scatter index (OSI), Strehl ratio (SR) and modulation transfer function cutoff frequency (MTFcutoff).ResultsThe safety and efficacy indices were 1.09 ± 0.12 and 1.03 ± 0.17, respectively, at the 5-year follow-up. No significant changes in SE from 1 month to 5 years postoperatively were found. The OSI significantly increased at 1 and 3 months postoperatively (p < 0.01 and p < 0.01) and declined at 1 and 5 years (p = 0.81 and p = 0.87). MTFcutoff and SR showed similar trends. Coma, spherical aberration and total higher-order aberration significantly increased after SMILE (p < 0.01) and remained stable from 1 month to 5 years after surgery (p > 0.05). Contrast sensitivity in the photopic and mesopic condition showed no significant changes during 5-year follow-up (p > 0.05).ConclusionThe SMILE procedure is satisfactory in terms of optical quality for correcting moderate and high myopia in the long-term period.Trial RegistrationChiCTR-ONRC-13003114.

Pure ICL Implantation: A Novel Ophthalmic Viscosurgical Device-Free Method.

Purpose To assess the clinical efficiency of a novel ophthalmic viscosurgical device-free (OVD-free) method for intraocular collamer lens (EVO-ICL) implantation in myopic eyes. Methods In this study, 40 patients underwent ICL implantation for both eyes: one eye underwent traditional ICL implantation, and the other eye underwent OVD-free (pure) ICL implantation. Preoperative and postoperative UDVA, BCVA, equivalent spherical degree (SE), IOP, visual quality index, subjective visual quality scale, corneal endothelial cell density (ECD), operation time, and complications were compared between and within the traditional and pure ICL implantation groups. Results Increased IOP >22 mmHg 2 h after surgery was noted in 8 eyes (20%) in the traditional group, but not in the pure group (0%, P < 0.001). Increased IOP relative to baseline was significantly higher at 2 h after surgery for the traditional group compared with the pure group (P < 0.001). UDVA, BCVA, and SE were significantly improved in the pure group compared with those in the traditional group 1 day (P < 0.001, P=0.003) after implantation, but not 1 week or 3 months after. Modulation transfer function cut-off frequency (MTF cut-off), Strehl ratio (SR), and OV20% were significantly better in the pure group than in the traditional group 1 day after implantation (P=0.013, P=0.009, and P=0.004). No significant difference in ECD changes within or between groups was observed (P > 0.05). The operation time for the pure group (2.897 ± 0.346 min) was significantly shorter than that for the traditional group (4.444 ± 0.656 min; P < 0.001). No complications were reported for either group during the observation period, except early IOP elevation in the traditional group. Conclusions The pure ICL implantation method was associated with faster visual acuity recovery, shorter operation time, and more stable intraocular pressure. Pure ICL represents a safe and convenient method for ICL implantation compared with the traditional method, completely eliminating OVD-related complications without causing additional complications.

Comparison of the optical quality after SMILE and FS-LASIK for high myopia by OQAS and iTrace analyzer: a one-year retrospective study

BackgroundTo compare the correction effect and optical quality after small-incision lenticule extraction (SMILE) and femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) for high myopia.Methods51 high myopia eyes after SMILE and 49 high myopia eyes after FS-LASIK were enrolled and divided into two groups retrospectively. The OQAS and iTrace analyzer were used for optical quality inspection. Between the two groups the spherical equivalent (SE), astigmatism, uncorrected distant visual acuity (UDVA), strehl ratio (SR), modulation transfer function cutoff frequency (MTF cutoff), objective scatter index (OSI) and wavefront aberrations were analyzed and compared before surgery and at 1, 6 and 12 months after surgery.ResultsAfter the operation: (1) SE and astigmatism declined and UDVA increased significantly in both groups, and UDVA was better after SMILE than FS-LASIK. (2) SR and MTF cutoff reduced and OSI increased significantly after SMILE and FS-LASIK. SR and MTF cutoff were significantly higher after SMILE than FS-LASIK. OSI was significantly lower after SMILE than FS-LASIK. (3) The total wavefront aberration, total low-order wavefront aberration, defocus and astigmatism aberration as well as trefoil aberration reduced significantly in both groups. The total high-order wavefront aberration increased significantly after FS-LASIK. The spherical and coma aberration increased significantly in both groups. The total high-order wavefront aberration and coma aberration at 1 month were higher after FS-LASIK than SMILE.ConclusionThe optical quality descended after SMILE and FS-LASIK. SMILE was superior to FS-LASIK at the correction effect and optical quality for high myopia. The combination of OQAS and iTrace analyzer is a valuable complementary measurement in evaluating the optical quality after the refractive surgery.Trial registrationThis is a retrospective study. This research was approved by the ethics committee of Xiangya Hospital and the IRB approval number is 201612074.

Optical and visual quality comparison of implantable collamer lens and femtosecond laser assisted laser in situ keratomileusis for high myopia correction.

To compare clinical outcomes and refractive stability of implantable collamer lens (ICL) implantation and femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) for high myopia correction. The Optical Quality Analysis System (OQAS) was used to evaluate clinical outcomes objectively after operation for high myopia correction. We compared the two procedures in terms of 1-year changes in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), safety index, efficacy index, spherical equivalent, modulation transfer function (MTF) cutoff frequency, strehl ratio (SR) and objective scatter index (OSI). At 1y postoperatively, the safety indices were 1.33±0.27 in ICL group, and 1.17±0.24 in FS-LASIK group. 39.58% in the ICL group and 27.59% in the FS-LASIK group gained CDVA in 2 lines or better than that in preoperative CDVA. The efficacy indices were 1.28±0.22 in ICL group, and 1.13±0.26 in FS-LASIK group. The changes of spherical equivalent from 1wk to 1y postoperatively was -0.12±0.37 D in ICL group, and -0.79±0.58 D in FS-LASIK group (P<0.05). Spherical equivalent within ±0.50 D was achieved in 97.92% in ICL group and 68.97% in FS-LASIK group. MTF cutoff frequency were higher with ICL as compared to FS-LASIK (P<0.05) at each postoperative follow-up stage; for postoperative 1mo later, SR was statistically significant difference between two groups (P<0.05); with no statistically significant difference in OSI between two groups (P>0.05) in postoperative 3mo later. ICL implantation and FS-LASIK procedures both provide good safety and predictability in high myopia correction. ICL implantation provides better clinical outcomes and refractive stability than FS-LASIK.

Implantable collamer lens with a central hole for residual refractive error correction after corneal refractive surgery.

The present study aimed to assess the visual and refractive outcomes of an implantable collamer lens with a central hole (ICL V4c) for residual refractive error correction after corneal refractive surgery in individuals with myopia. A total of 16 eyes of eight consecutive patients with myopia undergoing ICL V4c implantation after corneal refractive surgery were investigated. The uncorrected visual acuity (VA) and best-corrected VA were examined prior to surgery and at 1, 3 and 6 months after surgery. The post-operative values of the modulation transfer function (MTF) cutoff frequency, Strehl ratio (SR), objective scattering index (OSI) and Optical Quality Analysis System (OQAS) values (OVs) were quantitatively assessed using an OQAS. At 6 months after surgery, the mean uncorrected LogMAR VA was 0.06±0.10 and the values had improved in 100% of the eyes. The mean MTF cutoff frequency, SR, OSI, OV 100%, OV 20% and OV 9%, were 31.294±4.321 cycles/degree, 0.187±0.039, 1.399±0.274, 1.066±0.261, 0.748±0.287 and 0.509±0.229, respectively. In conclusion, ICL V4c implantation for the correction of residual refractive error after corneal refractive surgery appeared feasible and safe and also had an excellent optical performance. However, long-term changes in visual quality require further investigation.

Analysis of related factors of optical quality in healthy Chinese adults: a community-based population study.

Background:In recent years, visual quality has been extensively investigated in various conditions. In this community-based population study, we analyzed the effects of aging, refraction, and Lens Opacification Classification System III (LOCSIII) score on retinal imaging quality in healthy Chinese adults.Methods:This cross-sectional study was conducted on sub-group subjects from The Handan Eye Study between October 2012 and January 2013. Healthy subjects over 30-years-old with logarithm of the minimal angle of resolution (logMAR) best-corrected visual acuity (BCVA) less than 0 were included. Retinal image quality was measured by optical quality analysis system (OQAS) and recorded as modulation transfer function cutoff frequency (MTFcutoff), OQAS value (OV) 100%, OV20%, OV9%, Strehl ratio (SR), and objective scatter index (OSI). The correlation between age, spherical equivalent refraction (SE), LOCSIII score, and optical quality parameters were investigated by multivariate analysis.Results:Among 1108 verified subjects, 690 subjects (1380 eyes) met the inclusion criteria. Their age ranged from 30 to 76 years, SE ranged from −4.75 to 2.75 D. They were divided into five age groups (30–39, 40–49, 50–59, 60–69, and ≥70 years) for further analysis. After multivariate analysis by mixed-effect linear model, SR (t = −3.03, P = 0.002), OV20% (t = −2.39, P = 0.017), and OV9% (t = −3.16, P = 0.001) significantly decreased with the increasing age, whereas logMAR BCVA (t = 4.42, P < 0.001) and OSI (t = 4.46, P < 0.001) significantly increased with age. As SE increased, SR (t = 2.74, P = 0.01), OV20% (t = 2.31, P = 0.02), and OV9% (t = 2.79, P = 0.005) significantly elevated, and OSI (t = −3.38, P < 0.001) significantly decreased. With the increase in cortical opacity score, all optical quality parameters except for SR significantly decreased, including MTFcutoff (t = −2.78, P = 0.01), OV100% (t = −2.78, P = 0.005), OV20% (t = −2.60, P = 0.009), and OV9% (t = −2.05, P = 0.040). As posterior sub capsular opacity score increased, MTFcutoff (t = −2.40, P = 0.02) and OV100% (t = −2.40, P = 0.01) significantly decreased, while OSI (t = 7.56, P < 0.001) significantly increased.Conclusions:In healthy Chinese adult population, optical quality-related parameters significantly decrease with the increasing age, and OSI significantly increases with age. In normal BCVA subjects, optical quality is significantly impacted by cortical and posterior sub capsular opacity rather than by nuclear opacity.

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.