Ocular Higher-order Aberrations Research Articles

Association of myopia and astigmatism with postoperative ocular high order aberration after small incision lenticule extraction

ObjectiveTo investigate the correlation between higher-order aberrations (HOA) after small incision lenticule extraction (SMILE) and the severity of myopia and astigmatism, along with the relevant factors. These findings will provide valuable insights for decreasing the occurrence of HOA after SMILE and enhancing visual quality.MethodsA total of 75 patients (150 eyes) with myopia and astigmatism who underwent SMILE were categorized into four groups based on the severity of myopia and astigmatism: Myopia Group 1 (Group M1, spherical diopter ranged from -1.00 D to -4.00 D), Myopia Group 2 (Group M2, spherical diopter ranged from -4.10 D to -10.00 D), Astigmatism Group 1 (Group A1, cylindrical diopter ranged from 0 D to -1.00 D), and Astigmatism Group 2 (Group A2, cylindrical diopter ranged from -1.10 D to -3.00 D). A comprehensive assessment was performed to examine the association between HOA and various relevant factors, including a detailed analysis of the subgroups.ResultsGroup M1 had significantly lower levels of total eye coma aberration (CA), corneal total HOA (tHOA), internal tHOA, and vertical CA (Z3-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{Z}}}_{3}^{-1}$$\\end{document}) after SMILE than Group M2 (P < 0.05). Similarly, Group A1 had significantly lower levels of total eye tHOA, CA, trefoil aberration (TA), corneal tHOA, TA, and vertical TA (Z3-3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{Z}}}_{3}^{-3}$$\\end{document}) after SMILE than Group A2 (P < 0.05). Pearson correlation analysis indicated a statistically significant positive relationship between the severity of myopia/astigmatism and most HOA (P < 0.05). Subgroup evaluations demonstrated a notable increase in postoperative HOA associated with myopia and astigmatism in Groups M2 and A2 compared with the control group. Lenticule thickness, postoperative central corneal thickness (CCT), postoperative uncorrected distance visual acuity (UDVA), and postoperative corneal Km and Cyl were strongly correlated with most HOA. Age, eyes, and postoperative intraocular pressure (IOP) were only associated with specific HOA.ConclusionHOA positively correlated with the severity of myopia and astigmatism after SMILE. However, this relationship was not linear. HOA after SMILE was influenced by various factors, and additional specialized investigations are required to establish its clinical importance.

Possible risk factors of opaque bubble layer and its effect on high-order aberrations after small incision Lenticule extraction.

To evaluate the possible risk factors of opaque bubble layer (OBL) formation in small incision lenticule extraction (SMILE) surgery and its effects on visual quality. Fifty-six eyes from 28 patients were included in this study. The preoperative parameters and intraoperative designs were recorded. Corneal high-order aberrations (HOAs), point spread function (PSF), and modulation transfer function (MTF) were measured using iTrace at pre-operation, 1 week, 1 month, and 3 months after SMILE. Generalized Estimating Equation and Linear Mixed Effects Model were employed for statistical analysis. The mean OBL area in SMILE surgery was 2.75% ± 1.25%. The patients were divided into groups based on whether the OBL was greater than the mean group or less than the mean group. Compared to the group with a smaller OBL area, the group with the larger OBL area had steeper corneal curvature and thinner cap thickness, the OBL area was positively correlated with the preoperative keratometry (r = 0.21, p = 0.04) and preoperative spherical value (r = 0.47, p = 0.01). The group with the larger OBL area induced more corneal SA and trefoil at 1 week postoperatively, but the difference was not significant at 1 month and 3 months postoperatively. A steep corneal curvature, thin cap thickness, and high preoperative spherical value are possible risk factors for OBL formation in SMILE surgery. The OBL increased the ocular and corneal HOAs postoperatively for a short period (1 week), while it did not affect the long-term outcomes.

Changes in pupil size, ocular wavefront aberrations, and accommodation in healthcare workers using FFP3 masks.

To evaluate changes in pupil size, ocular wavefront aberrations (WA), and accommodation in healthcare workers after 4-h usage of Filtering Facepiece class 3 (FFP3) masks. This prospective study included 22 healthy healthcare workers. Pupil size, ocular WA, and accommodation changes before and after FFP3 mask usage were evaluated using a Hartmann Schack aberrometer. Accommodative responses to stimulus ranging from 0 to 5 diopters (D) in increments of 0.5 D were assessed. Ocular high-order aberrations (HOAs) were recorded at baseline and at every accommodative stimulus. Oxygen saturation (SpO2) was measured by pulse oximetry before and after the mask usage. The mean age was 36.6 ± 8.5 years. The SpO2 significantly decreased from 98.95 to 97.95% after usage of the FFP3 mask (p < 0.001). The mean pupil size did not significantly differ before (6.22 ± 0.75 mm) and after (6.38 ± 0.83 mm) the 4-h mask usage (p = 0.093). The mean total RMS of the total HOAs was 0.36 ± 0.17 before and 0.39 ± 0.15 after the mask usage (p = 0.071). Post-mask accommodation showed a significant decrease at the 2 D (p = 0.041), 2.5D (p = 0.022), and 3 D (p = 0.025) stimuli. The present study shows that after 4 h-usage of FFP3 mask, both SpO2 and accommodative response to increasing stimuli might be significantly decreased.

Analysis of the relationship between lens morphology and aberrations in patients with myopia: a cross-sectional study.

To investigate the relationship between lens morphology and aberrations in patients with myopia. This cross-sectional study included 155 patients with myopia in their right eyes. Spherical power and cylindrical power were achieved by cycloplegic autorefraction. The eyes were divided into three groups for analysis based on their spherical equivalent (SE) values. The 4mm and 6mm ocular and internal aberrations were measured using the OPD-scan III. Lens parameters were measured using CASIA2, including lens thickness (LT), radius of anterior/posterior lens surface curvature (RAL/RPL), lens decentration (DEC), and lens tilt (TILT). The differences of lenticular parameters and aberration parameters among the three groups analyzed with ANOVA or Kruskal Wallis test. Pearson correlation or Spearman correlation analysis was performed to evaluate the relationships between the lens parameters and aberrations. A p value < 0.05 indicated statistical significance. The difference in LT, RAL, DEC and TITL among the three groups was statistically significant (p < 0.05). And there were differences among differences in internal high-order aberrations, spherical aberration, and coma aberration(p < 0.05).Spherical power was positively correlated with LT and TITL (p < 0.05) and negatively correlated with DEC, RAL, and RPL (p < 0.05). Cylindrical power was positively correlated with LT (p < 0.05) and negatively correlated DEC (p < 0.05); The lenticular parameters (LT, RAL, DEC, and TILT) were mainly correlated with the ocular and internal spherical aberration. LT and DEC were correlated with ocular and internal higher-order aberrations and comaaberration. DEC and LT were the main factors affecting aberrations in patients with myopia.

A Comprehensive Wavefront Assessment of Keratoconus Using an Integrated Scheimpflug Corneal Tomographer/Hartmann-Shack Wavefront Aberrometer.

To characterize higher-order aberrations (HOAs) in different severities of keratoconus (KC) from the anterior and posterior corneal surfaces and whole eye using an integrated Scheimpflug corneal tomographer/Hartmann-Shack wavefront aberrometer. This study included eyes with clinical KC, topographic KC (no clinical signs), fellow eyes with very asymmetric ectasia with normal topography and no clinical signs (VAE-NT), and control eyes. Corneal and ocular wavefront aberrations were obtained using an integrated Scheimpflug tomographer/Hartmann-Shack wavefront aberrometer. The diagnostic capability of distinguishing VAE-NT from the control was also tested. This study included 68 eyes with clinical KC, 44 with topographic KC, 26 with VAE-NT, and 45 controls. Clinical KC had significantly greater total HOAs and coma from the anterior and posterior corneal surfaces and whole eye than the other groups ( P <0.05). Although topographic KC had significantly greater values in all wavefront parameters than the control ( P <0.05), ocular and corneal HOAs did not differ between the VAE-NT and control groups. The coma from the anterior cornea in topographic KC was significantly greater than that in VAE-NT ( P <0.05); the coma from the posterior cornea and whole eye did not differ. Total HOAs from the anterior corneal surface exhibited the highest area under the receiver operating characteristic curve value of 0.774 (sensitivity, 73%; specificity, 78%). A comprehensive wavefront assessment can be used to quantitatively evaluate corneal and ocular HOAs across various severity of KC. Total HOAs from the anterior corneal surface exhibited the potential ability in distinguishing VAE-NT from the control eyes.

Optical Quality and Visual Performance With Different Toric Contact Lens Designs.

To evaluate the optical quality of different toric contact lens (CL) designs and compare their on-eye visual correction performance. Twenty soft CL wearers aged 20 to 39 years were enrolled. Two daily disposable silicone-hydrogel toric CLs were tested: the "Eyelid Stabilized Design" (ESD-CL) and prism-ballast design (PB-CL); a spherical daily disposable silicone hydrogel CL (spherical CL) was used as a control. On-eye performance was compared for corrected distance visual acuity (CDVA), astigmatism, and ocular higher-order aberrations (HOAs); astigmatism and ocular HOAs were measured with a wavefront sensor. The subjective quality of vision, rated for "blurred vision" and "double vision," lens rotation, and fitting were also compared. The ESD-CLs, PB-CL, and no-CL provided better CDVA than spherical CL ( P <0.05). Compared with spherical CL and no CL, PB-CL and ESD-CLs caused significantly lesser astigmatism ( P <0.05). Coma was significantly lesser with ESD-CLs than that with PB-CL ( P <0.05); total HOAs did not differ among the four conditions. The subjective ratings for blurred and double vision were significantly lower with ESD-CLs than those with spherical CL ( P <0.05). Toric CLs provide a better CDVA than spherical CLs. However, differences in coma and subjective symptoms may occur because of the design of toric CLs.

Quality of Vision and Ocular Higher Order Aberrations after SMILE for Myopia and Myopic Astigmatism

Background Previous studies have shown considerable amounts of higher order aberrations following SMILE. In our study we aim at accurately quantifying the higher order aberrations following SMILE in myopia and myopic astigmatism. Objective To detect the effect of SMILE on quality of vision and the incidence of higher order aberrations following SMILE. Patients and Methods This is a prospective study that included 30 eyes of 18 patients presented in the outpatient clinic seeking advice for myopic refractive surgical correction. The study was conducted in accordance with the ethical standards stated by the ethical committee of Ain shams university hospitals with informed consents obtained from all participants. Results On studying the post-operative corneal third order aberrations we detected increase in post-operative vertical and horizontal coma, and spherical aberrations with non-significant change in vertical and horizontal trefoil. According to our study results, SMILE is an effective refractive surgery that improves visual acuity. That causes decrease in quality of vision through modulation transfer ratio and increase in ocular higher order aberrations. Conclusion SMILE (small incision lenticule extraction) is an efficient modality for refractive surgical correction of myopia and myopic astigmatism, with significant post-operative improvement in unaided visual acuity detected post-operative increase in the ocular HOAs. Total coma, trefoil and sphere increase significantly in mesopic more than photopic pupil. The degree of myopia didn’t affect the ocular higher order aberrations except for modulation transfer ratio.

Comparison of visual performance and image quality between a myopia-control contact lens and a single-vision contact lens

ObjectiveThis study aimed to evaluate the visual performance and image quality of concentric dual-focus-designed contact lenses (CLs) compared with single-vision CLs in myopic Chinese people. MethodsTwenty myopic volunteers aged between 18 and 26 years were recruited at a university eye hospital to wear both defocus-incorporated soft contact (DISC) lenses and single-vision CLs for 1 week in random order. High- and low-contrast visual acuity (VA), contrast sensitivity (CS), ocular higher-order aberrations (HOA), Strehl ratio and the Quality of Vision (QoV) questionnaire were assessed with each type of CL at weekly follow-up. ResultsDistance VA was not affected by DISC lenses compared to single-vision CLs in either high (p = 0.414) or low contrast (p = 0.431). However, there was a significant reduction in low-contrast near VA with DISC lenses compared with single-vision CLs (p = 0.011). The differences of CS between DISC lenses and single-vision CLs were significantly associated with lighting conditions and spatial frequencies (F = 128.81, P < 0.001). Compared with single-vision CLs, wavefront aberrations of DISC lenses were significantly increased in total HOA, trefoil, and spherical aberrations for either 3.0 mm or 6.0 mm pupil size. The Strehl ratio wearing DISC lenses reduced significantly compared to the single-vision CLs (p < 0.001) at a pupil diameter of 6.0 mm. QoV scores were higher overall (p = 0.026) and frequency (p = 0.019) with DISC lenses than with single-vision CLs, indicating poorer visual performance. ConclusionDISC lenses provide satisfactory distance VA. However, the higher scores of the QoV questionnaire with DISC lenses may be related to decreased CS at medium or high spatial frequencies and increased higher-order aberrations.

Four-year visual outcomes and optical quality of SMILE and implantable collamer lens V4c (EVO-ICL) implantation for high myopia: a retrospective study

BackgroundTo compare the 4-year visual outcomes of implantable collamer lens V4c (EVO-ICL) implantation and small incision lenticule extraction (SMILE) for high myopia and astigmatism.MethodsThis retrospective case study included 64 eyes of 40 patients. These patients with preoperative manifest refraction spherical equivalent (SE) between − 6.00 and − 10.00 diopters (D) were screened from the database of SMILE and EVO-ICL implantation procedures in 2015. The ICL group [32 eyes of 19 patients (mean age, 29.6 ± 6.3 years); mean SE, -8.71 ± 1.06 D] and SMILE group [32 eyes of 21 patients (mean age, 27.7 ± 5.6 years); mean SE, -8.35 ± 0.65D] were compared. All patients were then prospectively examined at a four-year follow-up for routine postoperative examinations, higher-order ocular aberrations, retinal image quality and a questionnaire.ResultsThe safety indexes were 1.15 ± 0.14 and 1.22 ± 0.21 (P = 0.36) for the SMILE and ICL groups, respectively. No eyes lost two or more lines of CDVA in either group. The efficacy indexes were 0.97 ± 0.16 and 0.96 ± 0.19 (P = 0.87), respectively. Twenty-three eyes (72%) in ICL and 26 eyes (81%) in SMILE groups were within ± 0.5 D of the attempted SE (P < 0.01). ICL-treated eyes had significantly less spherical aberration and coma (P < 0.01 and < 0.05, respectively) postoperatively. Halos were the prevalent visual disturbance in both groups.ConclusionSMILE and EVO-ICL implantation provided safe and effective correction of high myopia. SMILE showed slightly better long-term predictability. Mild postoperative visual disturbances were observed after ICL and SMILE at 4-year follow-up.

Five-year results of iontophoresis-assisted transepithelial corneal cross-linking for keratoconus

PurposeTo assess long-term efficacy and safety of iontophoresis-assisted transepithelial corneal cross-linking (I-CXL) for keratoconus.Patients and methodsTwenty-seven eyes of 21 patients (15 M, 6F) affected by progressive keratoconus were evaluated. All subjects were treated with iontophoresis-assisted transepithelial CXL. The patients were examined at baseline and each 6 months after the CXL procedure. Only subjects who completed the follow-up of 5 years were considered in this study. The main outcome measures were uncorrected visual acuity (UCVA), corrected visual acuity (CDVA), corneal transparency and corneal parameters such as K-max, central corneal thickness (CCT) and at the thinnest point, and high-order ocular aberrations (HOAs). The ABCD system was used to determine the progression and re-progression of ectasia.SettingOphthalmology Clinic, University Hospital of Messina, Messina, Italy.ResultsAt 5 years, significant improvements of UCVA from 0.53 ± 0.33 logMAR to 0.4 ± 0.33 logMAR (p = 0.001) and HOAs (p = 0.01) were registered. No significant changes of CDVA (p = 0.4), K-max (p = 0.75), CCT (p = 0.5) were observed at the end of follow-up period.The ABCD system showed re-progression in 25.9% of eyes after 5 years. No adverse events such as corneal opacities and infections were reported.ConclusionsIontophoresis-assisted transepithelial CXL resulted to be safe and effective to stabilize progressive keratoconus in adults at a long-term follow-up.

The Effects of Blue-Light Filtering Intraocular Implants on Glare Geometry

Purpose One common complaint with natural opacified lenses is the deleterious effects of higher-order ocular aberrations and intraocular scatter, such as halos and starbursts, which are not always remedied with surgery and intraocular lens (IOL) implantation. Blue-light filtering (BLF) IOL filter scatter-prone short-wave light. Here, we determine whether BLF IOL reduce halo and starburst size. Methods This study was a case-control design, between- and within-subjects (contralateral implantation). Sixty-nine participants with either the BLF IOL (n = 25; AlconSN60AT), clear IOL (n = 24; AlconSA60AT or WF), or both (n = 20) IOL participated. Participants were exposed to a point source of broadband simulated sunlight, which created the appearance of halos/starbursts. Dysphotopsia was measured as the diameter of broadband light-induced halos and starbursts. Results A case-control analysis. Halo size was significantly larger (t[35.05] = 2.98, p = 0.005) in participants with the clear control lens (M = 3°55′ ± 2°48′), compared to the BLF IOL (M = 1°84′ ± 1°34′). Starburst size was not significantly different between groups. Contralateral analysis. Halo size was significantly smaller (t = −3.89, p = .001) in test eyes with the BLF (M = 3°16′ ± 2°35′) compared to the fellow control eyes (M = 5°42′ ± 3°17′). Starburst size was also significantly smaller (t = −2.60, p < 0.018) in BLF test eyes (M = 9°57′ ± 4°25′) than the fellow eye with the clear IOL (M = 12°33′ ± 5°25′). Conclusions BLF IOL filter short-wave light and mimic retinal screening by the young, natural crystalline lens. Such filtering can reduce some deleterious effects of bright light by decreasing ocular diffusion/halos and starbursts.

Effect of Upper Lid Blepharoplasty Surgery on Corneal Topography and Corneal High-Order Aberrations.

The objective of this study was to prospectively investigate the effect of upper eyelid blepharoplasty surgery for dermatochalasis on corneal topographic data and high-order aberrations (HOAs). Fifty eyelids of 50 patients with dermatochalasis who underwent upper lid blepharoplasty surgery were prospectively studied. A Pentacam (Scheimpflug camera, Oculus) device was used to measure corneal topographic values, astigmatism degree, and HOAs before and at 2 months after upper eyelid blepharoplasty. The mean age of the patients included in the study was 55.96 ± 12.4 years, 40 (80%) were female and 10 (20%) were male. We found no statistically significant difference in the pre-and postoperative values of corneal topographic parameters (p > 0.05 for all). In addition, we observed no significant postoperative change in the root mean square values of low, high, and total aberration values. In HOAs, we detected no significant change in spherical aberration, horizontal and vertical coma, and vertical trefoil; we only found a statistically significant increase in horizontal trefoil values after surgery (p < 0.05). In our study, we found that upper eyelid blepharoplasty did not cause significant changes in corneal topography, astigmatism, and ocular HOAs. However, studies are reporting different results in the literature. For this reason, it is important for patients considering upper eyelid surgery to be warned about visual changes that may occur after surgery.

Pattern of increase in Spherical Aberration and Coma After Femtosecond Laser Assisted In-Situ Keratomileusis Using an Aspheric Ablation Profile

Purpose: To determine the contribution of spherical aberration and coma to the total ocular high order aberration before and after femto laser-assisted in-situ keratomileusis using an aspheric ablation profile. Methods: This is a prospective interventional study that was conducted on 34 eyes of 17 patients in the interval between January 2021 and June 2021. Patients did a preoperative aberrometry and corneal tomography. They underwent FS-LASIK surgery using an aspheric ablation profile. The total ocular aberrometry and corneal tomography were repeated one month postoperatively. Results: The mean preoperative contribution of coma to total ocular HOA was 52.16 % with SD of ± 25.59% which declined to 49.48 % with SD of ± 22.53 % postoperatively. The mean preoperative contribution of SA to total ocular HOA was 38.91 % with SD of ± 15.35 % which increased significantly to 51.25 % with SD of ± 16.55 % postoperatively. Conclusion: Post-operative contribution of corneal spherical aberrations to total ocular HOA showed a statistically significant increase compared to pre-operative. However, there was no significant change in coma contribution.

Higher order aberrations and visual function in a young Asian population of high myopes

PurposeTo examine the associations between higher order aberrations (HOAs), visual performance, demographics, and ocular characteristics in a young Asian population with high myopia. MethodsThis was a retrospective review of military pre-enlistees conducted between March 2014 to September 2018. Visual acuity and contrast sensitivity were tested under photopic, mesopic and simulated night conditions. Ocular, corneal and internal HOAs were measured with a Hartmann–Shack wavefront aberrometer (KR-1W, Topcon Co., Tokyo, Japan). Results522 eyes of 263 consecutive subjects with severe high myopia (defined as spherical equivalent refraction [SER] ≤ −10.00D) in at least one eye, and high myopia (SER ≤ −6.00D) in the fellow eye, [mean (SD) SER −11.85 (2.03D)] were analysed. The mean (SD) age of subjects was 18.5 (1.6) years. Chinese eyes had significantly greater internal total HOA root-mean-square (RMS) compared to Malay eyes [mean difference (SD) 0.0246 (0.007) μm, p < 0.001). More negative SER was associated with greater ocular total HOA (p = 0.038), primary coma (p = 0.003) and tetrafoil (p = 0.025) RMS, as well as more positive ocular (p = 0.003) and internal primary spherical aberration (p = 0.009). Greater ocular total HOAs was associated with reduced visual acuity in simulated night conditions and low contrast, decreased contrast sensitivity under mesopic and simulated night conditions (all p < 0.05). ConclusionsGreater HOAs were associated with Chinese ethnicity and more negative SER in a young Asian population with high myopia. Greater HOAs were associated with poorer visual performance in low luminance and reduced contrast conditions.

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.

Central and Peripheral Ocular High-Order Aberrations and Their Relationship with Accommodation and Refractive Error: A Review.

High-order aberrations (HOAs) are optical defects that degrade the image quality. They change with factors such as pupil diameter, age, and accommodation. The changes in optical aberrations during accommodation are mainly due to lens shape and position changes. Primary spherical aberration (Z(4.0)) is closely related to accommodation and some studies suggested that it plays an important role in the control of accommodation. Furthermore, central and peripheral HOAs vary with refractive error and seem to influence eye growth and the onset and progression of myopia. The variations of central and peripheral HOAs during accommodation also appear to be different depending on the refractive error. Central and peripheral high-order aberrations are closely related to accommodation and influence the accuracy of the accommodative response and the progression of refractive errors, especially myopia.

Evaluating early-stage disk halo changes after small incision lenticule extraction.

To investigate early changes in the disk halo under different light conditions after myopic small incision lenticule extraction (SMILE). This prospective study included 70 eyes of 70 myopic patients aged 18-33 years, with a spherical equivalent (SE) of -5.87 ± 1.86 D, who underwent SMILE. The subjective refraction, higher-order aberrations (HOAs), pupillometry, and halo were measured preoperatively and postoperatively to analyse disk halo variations and correlated factors. At 5 cd/m2 and 1 cd/m2 luminance, the halo radius in the high myopia (HM) group reached a postoperative peak after 1 week (p = 0.000 and 0.019, respectively), and recovered to baseline after 3 months. In the low-to-moderate (LM) myopia group, the halo radius did not differ 1 week postoperatively compared to the preoperative level (p = 0.015), but significantly improved after 3 months (p = 0.000). The halo radius correlated with SE, uncorrected distance visual acuity (UDVA), ocular HOAs, coma, and the pupillary light reflex in the LM group at all time points, but there were no correlations in the HM group. Halo symptoms occurred early after SMILE, but recovered within 3 months. The recovery process was slower in the HM group than in the LM group, and the halo radius correlated with SE, UDVA, ocular HOAs, coma, and the pupillary light reflex.

Comparison of Postoperative Safety, Efficacy, and Visual Quality after SMILE for Myopic Patients with Different Corneal Thicknesses

Purpose To investigate the safety, efficacy, and visual quality of small incision lenticule extraction (SMILE) in different corneal thickness patients with myopia or myopic astigmatism. Methods This prospective cohort study included 191 right eyes of 191 patients. Eyes were divided into three groups according to preoperative central corneal thickness (CCT) (Preoperative central corneal thickness (CCT) was the group indicator.) There were 31 eyes in the thin cornea group (CCT ≤500 um (μm), TC), 94 eyes in the moderate corneal thickness group (CCT ≥501 um (μm) and ≤550 um (μm), MD) and 66 eyes in the thick cornea group (CCT ≥550 um (μm), TK). Comparisons in uncorrected (UDVA) and best-corrected distance visual acuity (BDVA), manifest refractive spherical equivalent (SE), preoperative mesopic/photopic contrast sensitivity (CS), ocular higher-order aberrations (HOAs) at a 6mm analytical pupil diameter, and visual quality questionnaires were made (performed) among the three groups during the postoperative six months. Subgroup analyses were made based on preoperative SE. Results The safety indices at six months were 1.15 ± 0.18, 1.14 ± 0.17, and 1.18 ± 0.17, respectively (p = 0.374), and the efficacy indices at six months were 1.07 ± 0.25, 1.12 ± 0.22, and 1.11 ± 0.21, respectively (p = 0.599). The postoperative SE was −0.07 ± 0.52D, −0.14 ± 0.38D, and −0.05 ± 0.46D after SMILE in the three groups, respectively (p = 0.376). No significant difference was found in mesopic/photopic CS, HOAs, and visual quality among different corneal thickness groups and SE groups. Postoperative SE and efficacy indices were the lowest in thin cornea eyes with ultra-high myopia (over −9.00 D). Conclusions SMILE provides comparable safety, efficacy, and visual quality results in different corneal thickness patients. Those with myopia higher than -9.00 D had less efficacy after surgery, especially in thin cornea patients.

Characterization and prediction of the clinical result with a specific model of mini-scleral contact lens in corneas with keratoconus

BackgroundTo investigate which factors are correlated with the visual improvement achieved with a specific model of scleral contact lens (SCL) in keratoconus (KC) eyes and to define a model to predict such improvement according to the pre-fitting data. In addition, the changes occurred with the fitting of a specific model of SCL during a period of 3 months in corneas with KC have been investigated.MethodsLongitudinal retrospective study including 30 eyes of 18 patients (age, 14–65 years) with KC fitted with the SCL ICD16.50 (Paragon Vision Sciences). Visual, refractive, corneal tomographic and ocular aberrometric changes were evaluated during a 3-month follow-up. Likewise, the characterization of the post-lens meniscus was performed by optical coherence tomography (OCT) with the measurement of central, nasal and temporal vaults.ResultsThe visual acuity increased significantly from a mean pre-fitting value with spectacles of 0.23 ± 0.07 logarithm of minimal angle of resolution (logMAR) to a mean value of 0.10 ± 0.04 logMAR after 1 month of SCL wear (P < 0.001). An improvement of 1 or more lines of visual acuity with the SCL occurred in 62.1% of the eyes. A significant decrease in central, nasal, and temporal vault was observed after 1 month of SCL wear (P ≤ 0.046). Likewise, there was a significant difference between nasal and temporal vaults during the first month of SCL use (P = 0.008). Furthermore, a significant reduction of ocular high order (P = 0.028) and primary coma root mean square (P = 0.018) was found with the SCL. A predicting linear equation of the change in visual acuity achievable with the SCL was obtained (P < 0.001, R2 = 0.878) considering the pre-fitting spectacle corrected distance visual acuity, and the power and sagittal lens of SCL.ConclusionsThe scleral contact lens evaluated provides an efficacious visual rehabilitation in KC due to the improvement of visual acuity and the correction of low and high-order ocular aberrations. This visual acuity improvement can be predicted from some pre-fitting variables.

Influence of decentration and tilt of Tecnis ZCB00 on visual acuity and higher order aberrations.

To determine the influence of decentration and tilt of a pseudophakic aspheric intraocular lens (IOL) on visual acuity (VA) and higher-order aberrations (HOAs), and to analyze the agreement between pupil center/axis and iridocorneal angles center/axis when assessing IOL decentration and tilt. A prospective interventional case series study including thirty-three patients undergoing Tecnis ZCB00 (Abbott Medical Optics) implantation. IOL decentration and tilt with respect to two reference systems (pupil and iridocorneal angles centers/axes), in cartesian (X,Y) and polar (radius/tilt, polar angle/azimuth) coordinates, were assessed with optical coherence tomography. VA and internal and ocular HOAs were evaluated. Multiple linear regression models and intraclass correlation coefficient (ICC) were computed. IOL decentration only showed a significant effect on internal HOAs for [Formula: see text] (R2 = 0.20, P = 0.04). IOL decentration with respect to the pupil center showed a significant effect on ocular [Formula: see text] (R2 = 0.18, P = 0.05), [Formula: see text] (R2 = 0.36, P = 0.001) and [Formula: see text] (R2 = 0.24, P = 0.02); and with respect to the center of iridocorneal angles, on ocular [Formula: see text] (R2 = 0.21, P = 0.03), [Formula: see text] (R2 = 0.32, P = 0.003), primary coma (R2 = 0.41, P < 0.001), and coma-like (R2 = 0.40, P = 0.001). Poor agreement between both reference systems was found for IOL decentration measurements (ICC ≤ 0.41), except for the polar angle coordinate (ICC = 0.83). Tilt measurements showed good agreement (ICC ≥ 0.75). Tecnis ZCB00 decentration and tilt values after uneventful implantation appear not to have influence on VA, and their effect on HOAs are not high enough to clinically affect quality of vision. Pupil and iridocorneal angles used as reference systems may be interchangeable for IOL tilt measurements, but not for decentration.