Modulation Transfer Function Cutoff Research Articles

Compound electrolyte intraocular irrigating solution produces better effects on vision recovery of cataract patients after surgery than Ringer lactate solution.

Intraocular irrigating solution is extensively applied in cataract surgery. This paper explored the difference and relationship between optical coherence tomography (OCT) and optical quality analysis system (OQAS) parameters induced by compound electrolyte intraocular irrigating solution (CEIIS) or Ringer lactate (RL) solution during uncomplicated cataract surgery. Totally 200 senior cataract patients were randomly divided into the CEIIS and RL groups (N = 100 patients/group). The anterior chamber was irrigated by CEIIS or RL during phacoemulsification. Patients were subdivided into diabetes mellitus (DM)+ and DM- groups. The central macular thickness (CMT), hyper reflective foci (HF), modulation transfer function cutoff frequency (MTF cutoff), Strehl ratio (SR), objective scatter index (OSI), and OQAS values (OVs) at 100%, 20%, and 9% contrast levels were measured preoperatively and 1day and 1week after operation using spectral-domain optical coherence tomography and OQAS II, respectively. Best-corrected visual acuity (BCVA) was assessed using the Snellen scale, followed by statistical analysis of its logarithm of the minimal angle of resolution. There were no significant differences in clinical characteristics between the CEIIS and RL groups. Both groups exhibited notably increased postoperative CMT, MTF cutoff, SR, OV at 100%, 20%, and 9% contrast levels, and reduced OSI, indicating CEIIS and RL improved postoperative visual quality. CEIIS surpassed RL solution in improving postoperative visual quality, decelerating the increase of macular HF numbers and CMT in DM+ patients and postoperative BCVA. There was no difference between CEIIS and RL in long-term vision improvement. CEIIS surpasses RL in postoperative visual recovery and retards increases of macular HF numbers and CMT in senior DM+ cataract patients.

Corneal densitometry in Chinese adults with healthy corneas: associations with sex, age, ocular metrics, and optical characteristics

BackgroundStandardized corneal densitometry (CD) values in large samples of healthy Chinese individuals are scarce. Therefore, we aimed to determine the standard CD values using a Scheimpflug camera in healthy corneas, investigate the correlations of sex, age, and ocular parameters with corneal density, and explore the impact of corneal density on the forward scattering and optical quality of the eye.MethodsThis retrospective observational study involved 990 healthy Chinese individuals, including 494 males and 496 females (mean age: 23.88 ± 6.90 years). The CD values at various depths and radial areas of 0–12 mm were measured using a Scheimpflug camera. Densitometric measurements were expressed in standardized grayscale units (GSU). The optical scatter index (OSI), modulation transfer function cutoff values (MTFcutoff), and Strehl’s ratio (SR) were also determined using an optical quality analysis system.ResultsThe average CD within a 12 mm diameter area was 16.26 ± 1.35 GSU. The highest and lowest optical densities at different depths were observed in the anterior (21.41 ± 2.16 GSU) and posterior (12.00 ± 1.01 GSU) layers, respectively (P < 0.001). Similarly, the maximum and minimum optical densities at different radial areas were observed in the 10–12 mm (14.09 ± 0.93 GSU) and 2–6 mm (25.93 ± 4.77 GSU) circles, respectively (P < 0.001). There was no significant difference in the average CD within a 12 mm diameter area between males and females (P > 0.05). However, upon adjusting for age, central corneal thickness (CCT), corneal curvature, white-to-white (WTW) corneal diameter, and axial length, females exhibited a greater average CD within the 12 mm diameter and in the 6–10 mm and 10–12 mm circles than males. Age-related changes in CD were evident, except in the 2–6 mm circle. CCT, corneal curvature, WTW corneal diameter, and partial depth correlated with CD in the radial area, and CD in different areas correlated with the OSI, MTFcutoff, and SR (P < 0.05).ConclusionsThis study provides the normative CD measurement data of Chinese adults with healthy corneas, emphasizing the significance of sex, age, CCT, corneal curvature, and WTW corneal diameter in CD evaluation. Notably, elevated CD can lead to increased forward scattering within the eye, thereby affecting the optical quality.

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, Strehl ratio, objective scatter index (OSI), and OQAS-II value (OQAS-II value 100%, OQAS-II value 20%, and OQAS-II value 9%) under natural conditions. Additionally, dynamic changes in OSI post-blinking, Tear film mean-OSI , and the corresponding standard deviation OSI were recorded. ResultsStatistically significant differences were observed among the groups in modulation transfer function cutoff, Strehl ratio, OSI, OQAS-II value 100 %, OQAs-II value 20 %, OQAs-II value 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 100 %, OQAS-II value 20 %, OQAS-II value 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.

Degradation of Photopic and Mesopic Contrast Sensitivity Function in High Myopes With Partial Posterior Vitreous Detachment.

The purpose of this study was to evaluate the effects of posterior vitreous detachment (PVD) on visual quality in patients with high myopia, as well as investigate the associated factors of photopic and mesopic contrast sensitivity function (CSF) in high myopia. Visual quality was comprehensively assessed in patients with high myopia. Visual acuity, contrast sensitivity (CS) at four spatial frequencies (3, 6, 12, and 18 cycles per degree [c.p.d.]) under photopic and mesopic conditions, as well as the modulation transfer function cutoff value (MTFcutoff), the objective scatter index (OSI), the Strehl ratio (SR), and internal aberrations, were measured in this cross-sectional study. This study included 94 eyes from 47 subjects with bilateral high myopia, including 23 eyes with complete PVD (cPVD), 21 eyes with partial PVD (pPVD), and 50 eyes without PVD (nPVD). There was no significant difference in visual quality between the cPVD group and the nPVD group. Whereas in eyes with pPVD, there was a degradation of overall photopic CSF (versus nPVD, P = 0.048), photopic CS at 3 c.p.d. (versus cPVD, P = 0.009 and versus nPVD, P = 0.032), photopic CS at 18 c.p.d. (versus nPVD, P = 0.033), overall mesopic CSF (versus nPVD, P = 0.033), and secondary astigmatism (versus cPVD, P = 0.044). Under photopic conditions, the factors affecting CSF were pPVD and SR, whereas the factors affecting mesopic CSF were pPVD, OSI, and ganglion cell-inner plexiform layer thickness. The pPVD impaired visual quality in patients with high myopia compared to nPVD or cPVD, and pPVD could be a factor explaining CSF at both photopic and mesopic illumination. Clinicians need to closely monitor patients with high myopia with pPVD due to the potential decline in visual quality and the development of vitreoretinal disorders.

Analysis of visual quality improvement after implantation of PanOptix trifocal intraocular lens in cataract patients with different axial lengths.

To assess the visual quality, both subjective and objective, of cataract patients with varying axial lengths (AL) after PanOptix trifocal intraocular lens (IOL) implantation and investigated the lens tilt and its correlation with visual outcomes. From July 2020 to June 2022, 70 patients (140 eyes) diagnosed with age-related cataracts and undergoing PanOptix implantation at Chongqing Eye and Vision Care Hospital, Aier Eye Hospital Group, were included. Patients were assigned to either the observation group (35 cases, 70 eyes with PanOptix trifocal IOL) or the control group (35 cases, 70 eyes with bifocal IOL). Patients were further subdivided based on AL into AL < 24 mm (observation group: 23 eyes; control group: 26 eyes) and AL ≥ 24 mm (observation group: 47 eyes; control group: 44 eyes). Postoperative follow-up lasted three months. Visual acuity (distant, intermediate, near), objective visual quality (Strehl ratio: SR, total eye modulation transfer function (MTF)), and visual aberrations were measured preoperatively and at 3 months post-operation. Postoperatively, all groups saw significant improvements in uncorrected distance visual acuity (UCDVA), uncorrected intermediate visual acuity (UCIVA), and uncorrected near visual acuity (UCNVA) compared to preoperative values (T0) (all P < 0.05). Notably, UCIVA was significantly better in the observation group than in the control group (P < 0.05). At three months (T1), reductions in total high-order aberration (tHOA), internal high-order aberration (iHOA), coma, and trefoil aberrations were observed in both groups compared to baseline, with more significant decreases in the observation group (all P < 0.05). Both SR and MTF cutoff showed marked improvement from T0 to T1, with the observation group experiencing greater enhancements (both P < 0.05). The defocus curve of the observation group showed a gentle slope between +0.5 D and -3.0 D, maintaining superior visual acuity compared to the control group (P < 0.05). Subjective visual quality scores at T1 were significantly higher than at T0 for both groups (P < 0.05), with patients in the observation group scoring higher than those in the control group across all AL categories (P < 0.05). Spearman correlation analysis indicated that the tilt after PanOptix trifocal IOL implantation was associated with tHOA (r = 0.273, P = 0.022), iHOA (r = 0.433, P < 0.001), Trefoil (r = 0.360, P = 0.002) and coma (r = 0.688, P < 0.001). PanOptix trifocal IOL implantation in cataract patients across different AL significantly enhances visual quality compared to bifocal IOLs, suggesting a strong case for its clinical adoption.

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.

Influence of decentration of plate-haptic toric intraocular lens on postoperative visual quality

BackgroundTo evaluate the influence of decentration of plate-haptic toric intraocular lens (IOLs) on visual quality.MethodsThis study enrolled 78 eyes of 78 patients. Patients in group A were implanted with toric IOLs, and patients in group B were implanted with monofocal IOLs. All patients were divided into group A1 and B1 (decentration below 0.3 mm) and group A2 and B2 (decentration above 0.3 mm). The uncorrected distance visual acuity (UDVA), best corrected visual acuity (BCVA), modulation transfer function cutoff (MTF cutoff), objective scatter index (OSI), strehl ratio (SR), optical interference and patients’ satisfaction were measured in different pupils at three months postoperatively. The associations between decentration and visual quality were analyzed by Spearman correlation.ResultsThere were no significant differences in UDVA, BCVA, MTF cutoff, OSI, SR, optical interference and patients’ satisfaction among subgroups. The differences in decentration between groups A and B were not statistically significant. In group A2, the total higher order aberrations (tHOAs) at pupil sizes of 3 mm (P = 0.046), 5 mm (P = 0.014), spherical aberrations at pupil sizes of 3 mm (P = 0.011), 4 mm (P = 0.014), 5 mm (P = 0.000), secondary astigmatism at pupil sizes of 3 mm (P = 0.002), 4 mm (P = 0.005) were higher than in group B2. Compared to group A1, group A2 had higher spherical aberrations at pupil sizes of 4 mm (P = 0.042), 5 mm (P = 0.001), 6 mm (P = 0.038), secondary astigmatism at pupil sizes of 3 mm (P = 0.013), 4 mm (P = 0.005), 6 mm (P = 0.013). Group B2 has higher coma and secondary astigmatism than group B1 at 6-mm pupil (P = 0.014, P = 0.045). Significant positive correlations were found between spherical aberrations and the decentration of group A1 and A2 at 6-mm pupils.ConclusionThe decentration above 0.3 mm negatively affected visual quality due to increased tHOAs, spherical aberrations, coma and secondary astigmatism aberrations, the influence become larger with increasing pupil diameter. And toric IOLs are more affected by decentration than monofocal IOLs.

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.

Tear film dynamics of a new soft contact lens.

To present the objective metrics from a study that evaluated the clinical performance of a senofilcon A contact lens, both with and without a new manufacturing technique. This was a single-site, five-visit, controlled, randomised, subject-masked, 2 × 2 crossover study (May-August 2021) with a 2-week lens dispensing period (bilateral wear) and weekly follow-up visits. Healthy adult (18-39 years), habitual spherical silicone hydrogel contact lens wearers were included. The High-definition (HD) Analyzer™ was used to objectively measure the lens-on-eye optical system resulting from the study lenses at 1-week follow-up. Measurements assessed were vision break-up time (VBUT), modulation transfer function (MTF) cutoff, Strehl ratio (SR), potential visual acuity (PVA) for 100% contrast and objective scatter index (OSI). Of the 50 enrolled participants, 47 (94.0%) were randomly assigned to one of the two possible lens wear sequences (test/control or control/test) and dispensed at least one study lens. The estimated odds ratio of VBUT > 10 s was 1.582 (95% confidence interval [CI]: 1.009 to 2.482) in test versus control lens. The least squares mean difference estimates of MTF cutoff, SR and PVA for 100% contrast between test versus control lens were 2.243 (95% CI: 0.012 to 4.475), 0.011 (95% CI: -0.002 to 0.023) and 0.073 (95% CI: -0.001 to 0.147), respectively. The estimated ratio of median OSI between test versus control lens was 0.887 (95% CI: 0.727 to 1.081). The test lens demonstrated superiority over the control lens with respect to VBUT and MTF cutoff. No serious adverse events were reported; eight adverse events (three ocular, five non-ocular) were indicated by six participants during the study. The test lens demonstrated an increased probability of having a longer VBUT (>10 s). Future studies may be designed to assess the efficacy and long-term use of the test lens in a larger population.

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.

The effect of orthokeratology lenses on optical quality and visual function in children.

To assess changes in optical quality and visual function in children after 3 months of wearing orthokeratology (OK) lenses. A total of 25 myopic children aged 8-12 years were recruited and completed the follow-up study. Optical quality, visual function and corneal morphology were assessed at baseline and at follow-ups 1 and 3 months after wearing OK lenses. Optical quality parameters mainly included the modulation transfer function (MTF) cutoff, objective scattering index (OSI), Strehl ratio (SR) and the predicted visual acuities (PVAs). Visual function was assessed by visual acuity, monocular contrast sensitivity function (CSF) across five spatial frequencies and the area under the log contrast sensitivity function (AULCSF) that was also computed as an index for overall CSF. The MTF cutoff and SR values both increased after 1 month of wearing the OK lenses (baseline vs. 1 month: P MTF = 0.008 and P SR = 0.049); this improvement plateaued after 3 months of lens wear (1 month vs. 3 months: P MTF = 0.626, P SR = 0.428). The corneal morphology also showed the similar change trend. The OSI showed the opposite change trend (baseline vs. 1 month: P OSI < 0.001; 1 month vs. 3 months: P OSI = 0.720). The mean CSF at 1.5 cpd decreased significantly after 1 month of wearing the lenses (baseline vs. 1 month: p = 0.001) and recovered after 3 months of lens wear (baseline vs. 3 months: p = 0.076). CSF at spatial frequencies of 3, 6, 12 and 18 cpd as well as the AULCSF did not significantly differ between any two timepoints (all Ps > 0.05). After 3 months of wearing OK lenses, the subjects exhibited a decrease in optical quality, similar to corneal morphology, whereas their visual function remained largely unchanged. Thus, the optical quality was more susceptible to OK lenses than visual function in children. The initial month of OK treatment of children is a key period to be paid close attention to deterioration of optical quality and visual function.

Differences in retinal images quality between normal and subclinical keratoconus and its association to posterior corneal asymmetry.

To compare retinal image quality in subclinical keratoconus and normal eyes using a double-pass aberrometer and to correlate it with posterior surface deformation. Sixty normal corneas were compared to 20 subclinical keratoconus (SKC) corneas. Retinal image quality was assessed using a double-pass system in all the eyes. The objective scatter index (OSI) modulation transfer function (MTF) cutoff, Strehl ratio (SR), and Predicted Visual Acuity (PVA) values at 100%, 20%, and 9% were calculated and compared between the groups. Posterior corneal asymmetry was measured using a combined Placido Dual Scheimpflug Analyzer, and correlations were tested with all optical quality parameters. Significant decrease in optical quality parameters was observed in SKC eyes compared with that in normal eyes. Subclinical KC eyes expressed greater scattering (OSI = 0.66 ± 0.36 vs 0.47 ± 0.26) and reduced contrast images (MTF and SR) than normal eyes, with 38.82 ± 9.4 and 0.22 ± 0.04, and 44.35 ± 7.1 and 0.24 ± 0.04, respectively. The reduction in the image contrast parameters (MTF and SR) was strongly correlated to the level of posterior corneal asymmetry in SKC. The greater the posterior asymmetry, the more affected was the image contrast, with r = -0.63 and -0.59, respectively for MTF and SR. Retinal image quality was significantly more affected in eyes with subclinical keratoconus than in normal eyes. The reduction in optical quality observed in subclinical keratoconus was strongly associated with the increased asymmetry of the posterior cornea.

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.

Impact of Dry Eye Disease on Visual Function and Quality after Femtosecond LaserAssisted In-Situ Keratomileusis

Purpose: The purpose of this study was to determine how objective and subjective parameters of dry eye disease correlate with objective vision quality changes following femtosecond laser in-situ keratomileusis (FS-LASIK) surgery in low and high myopes. Methods and Materials: This prospective, observational case series recruited patients undergoing bilateral FS-LASIK. Patients were divided into low/moderate and high myopia groups based on pre-operative assessment. Objective and subjective measurements of dry eye, as well as measurements of vision quality were obtained pre-operatively, 1-week, 1 month, and 3 months post-operatively. Thirty patients were included. The low/moderate and high myopia groups each contained 15 patients. Results: Non-invasive keratography tear break up time (NIKBUT) decreased after FS-LASIK in both groups. Objective scatter index (OSI) improved in the L/M myopia group but worsened in the H myopia group post-operatively. Modulation transfer function (MTF) cutoff improved in both groups post-operatively. A negative correlation was identified between the NIKBUT and both the OSI and MTF results. Changes in ocular surface disease index (OSDI) scores support these objective findings. Conclusion: The results of our study provide evidence that ocular surface changes associated with dry eye contribute to reduced subjective vision quality after FS-LASIK. Refractive surgeons should address dry eye pre-operatively and manage its sequalae post-operatively

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.

Evaluation of the Effects of Vitrectomy with Primary Epiretinal Membrane Peel on Optical Quality Using Double-Pass Aberrometry

Introduction: We performed a prospective, single-center, cohort study in order to evaluate the effects of vitrectomy with epiretinal membrane (ERM) peel on optical quality in patients with primary ERM. Methods: Thirty patients treated for primary ERM by vitrectomy with ERM peel were included from our tertiary university hospital ophthalmology department. The main study outcome was a variation in optical quality parameters measured using the HD Analyzer™ between preoperative and 2-month postoperative evaluations in operated eyes. Optical quality parameters comprised point spread function (PSF) width at 10% and 50%, objective scatter index (OSI), and modulation transfer function (MTF) cutoff. Contralateral non-operated eyes were used as an internal control for measurement reproducibility. Results: Mean PSF width at 10% (42.22 vs. 27.37 arc/min; p = 0.0002) and mean OSI (3.32 vs. 2.32; p = 0.0003) were significantly improved between pre- versus postoperative evaluations. Mean PSF width at 50% and mean MTF cutoff showed no changes. Subgroup analysis according to crystalline lens status gave similar results, demonstrating that improvements in mean PSF width at 10% and OSI were not lens-related. Non-operated eyes showed no changes in any of the parameters analyzed. Conclusion: Reduced light scattering measured by OSI indicates improved optical quality following vitrectomy with ERM peel among patients with primary ERM. OSI measurement could thus be a new parameter of interest in the preoperative assessment of primary ERM and other pre-vitrectomy assessments.

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.