-
Clinical Ophthalmology (Auckland, N.Z.) 2024To evaluate and compare the effect of femtosecond laser-assisted cataract surgery on corneal astigmatism in post-LASIK eyes and virgin eyes.
PURPOSE
To evaluate and compare the effect of femtosecond laser-assisted cataract surgery on corneal astigmatism in post-LASIK eyes and virgin eyes.
PATIENTS AND METHODS
Patients who underwent femtosecond laser-assisted cataract surgery were included in the study and categorized into two groups: Group A, consisting of patients with post-LASIK eyes, and Group B, consisting of patients with virgin eyes. Visual acuity, corneal astigmatism, and surgically induced astigmatism (SIA) were evaluated. Additionally, the correlation between SIA and preoperative corneal astigmatism, mean corneal curvature, and central corneal thickness was also analyzed.
RESULTS
A total of 168 eyes were enrolled in this study, with 62 eyes in Group A and 106 eyes in Group B. Significant differences in corneal astigmatism and SIA were observed between the two groups in the early postoperative period following cataract surgery (P<0.05). However, there was no significant difference at 6 months postoperatively (P>0.05). Corneal astigmatism demonstrated an against-The-rule shift in both groups postoperatively. No significant correlation was identified between SIA and preoperative corneal astigmatism, corneal curvature or corneal thickness. Additionally, there was no significant difference observed between the two groups in terms of uncorrected distance visual acuity (UDVA) at 6 months postoperatively.
CONCLUSION
The effect of femtosecond laser-assisted cataract surgery on corneal astigmatism in post-LASIK eyes and virgin eyes was different in the early postoperative period. However, there was no significant difference at 6 months postoperatively. The post-LASIK eyes exhibited a delayed recovery compared to the virgin eyes.
PubMed: 38863679
DOI: 10.2147/OPTH.S466201 -
Clinical Ophthalmology (Auckland, N.Z.) 2024Uncorrected refractive errors (REs) and amblyopia can lead to visual impairment with deleterious effects on quality of life and academic performance. Early detection and...
PURPOSE
Uncorrected refractive errors (REs) and amblyopia can lead to visual impairment with deleterious effects on quality of life and academic performance. Early detection and treatment by community vision care programs, such as the UCI EyeMobile for Children, can aid in addressing preventable vision loss.
METHODS
A total of 5074 children between the ages of 3 and 10 years were screened at 153 locations, including preschools, head start programs, and elementary schools within Orange County (OC), California (CA). Subsequently, 1024 children presented for comprehensive eye examinations. A retrospective analysis of all examined children was conducted, determining the frequency and severity of REs and amblyopia and the spectacle prescription rate by age. Propensity score matching analysis evaluated the effect of median household income on RE and amblyopia frequency.
RESULTS
Among those who failed initial screening and were subsequently examined, significant rates of REs and amblyopia were detected: myopia (24.4%), hyperopia (35.4%), astigmatism (71.8%), anisometropia (8.9%), amblyopia (7.0%), and amblyopia risk (14.4%). A majority (65.0%) of those examined received prescription spectacles from UCI EyeMobile, with around a third requiring a new or updated prescription. The frequency of REs and amblyopia and the spectacle prescription rate were uniform across OC congressional districts. Myopia and amblyopia risk was positively and negatively associated with household income, respectively.
CONCLUSION
The UCI EyeMobile for Children serves as a vital vision care program, providing free vision screening, comprehensive eye examinations, and spectacles. A significant number of children required examination, and a high frequency of REs and amblyopia were detected in examined children, with subsequent provision of prescription spectacles to most children.
PubMed: 38860118
DOI: 10.2147/OPTH.S460879 -
Optics Express Apr 2024Focus stabilisation is vital for long-term fluorescence imaging, particularly in the case of high-resolution imaging techniques. Current stabilisation solutions either...
Focus stabilisation is vital for long-term fluorescence imaging, particularly in the case of high-resolution imaging techniques. Current stabilisation solutions either rely on fiducial markers that can be perturbative, or on beam reflection monitoring that is limited to high-numerical aperture objective lenses, making multimodal and large-scale imaging challenging. We introduce a beam-based method that relies on astigmatism, which offers advantages in terms of precision and the range over which focus stabilisation is effective. This approach is shown to be compatible with a wide range of objective lenses (10x-100x), typically achieving <10 nm precision with >10 μm operating range. Notably, our technique is largely unaffected by pointing stability errors, which in combination with implementation through a standalone Raspberry Pi architecture, offers a versatile focus stabilisation unit that can be added onto most existing microscope setups.
PubMed: 38859306
DOI: 10.1364/OE.520845 -
Clinical Ophthalmology (Auckland, N.Z.) 2024To determine if factors pertaining to corneal thickness and elevation were linked to the prescribed back optic zone radius and overall diameter in keratoconus (group I),...
PURPOSE
To determine if factors pertaining to corneal thickness and elevation were linked to the prescribed back optic zone radius and overall diameter in keratoconus (group I), and cross-linked keratoconus (group II), cases successfully fitted with rigid contact lenses.
PATIENTS AND METHODS
A review of cases adapted to contact lens wear (Rose K™) and assessed using Pentacam™ (for corneal anterior surface topography, astigmatism, elevation, and topographic thickness variation) was undertaken to determine the significance of any correlation with comfort, lens usage, grading of keratoconus, corrected distance visual acuity (with glasses and contacts), refractive error, prescribed lens powers, back optic zone radius and overall diameter values were assessed.
RESULTS
Chief findings were, comfort was rated highly, lenses were worn for more than 10 hours/day in 75% of cases. RCL corrected distance logMAR acuities (median, mode, inter-quartile ranges) were 0.11, 0.12 (0.08-0.13) and 0.08, 0.08 (0.06-0.11) in groups I and II, respectively. Multiple linear regression revealed significant correlations (p<0.01) between the [A] back optic zone radius, the thinnest value of corneal thickness (x1) and anterior corneal surface elevation (x2). The respective r values were 0.471 in group I and 0.512 in group II. [B] overall diameter, x1 and x2. The respective r values were 0.282 in group I and 0.505 in group II.
CONCLUSION
RCLs were well-tolerated in both groups. The r values imply there is a 50% chance of correctly predicting the suitable back optic zone radius in both groups, a 50% chance of correctly predicting the overall diameter in group II and 28% in group I cases using just x1 and x2. The thinnest value of corneal thickness and anterior corneal surface elevation could be used to quickly select the BOZR and OD during RCL fitting. This has the potential to reduce chair-time, waste and improve efficiency.
PubMed: 38855010
DOI: 10.2147/OPTH.S463305 -
Turkish Journal of Ophthalmology Jun 2024To investigate the clinical efficacy and safety of the modified Cretan protocol in patients with post-laser in situ keratomileusis ectasia (PLE).
OBJECTIVES
To investigate the clinical efficacy and safety of the modified Cretan protocol in patients with post-laser in situ keratomileusis ectasia (PLE).
MATERIALS AND METHODS
In this retrospective study, 26 eyes of 16 patients with PLE were treated with the modified Cretan protocol (combined transepithelial phototherapeutic keratectomy and accelerated corneal collagen cross-linking). Visual, refractive, tomographic, and aberrometric outcomes and point spread function (PSF) were recorded preoperatively and at 6, 12, and 24 months after treatment.
RESULTS
Both uncorrected and best corrected visual acuity were stable at 24 months postoperatively compared to baseline (from 0.89±0.36 to 0.79±0.33 logarithm of the minimum angle of resolution [LogMAR] and 0.31±0.25 to 0.24±0.19 LogMAR, respectively, p>0.05 for all values). The mean K1, K2, Kmean, thinnest corneal thickness, and spherical aberration at baseline were 45.76±5.75 diopters (D), 48.62±6.17 D, 47.13±5.89 D, 433.16±56.86 μm, and -0.21±0.63 μm respectively. These values were reduced to 42.86±6.34 D, 45.92±6.74 D, 44.21±6.4 D, 391.07±54.76 μm, and -0.51±0.58 μm at 24 months postoperatively (p<0.001, p=0.002, p<0.001, p=0.001, and p=0.02, respectively). The mean spherical equivalent, manifest cylinder, Kmax, central corneal thickness, other corneal aberrations (root mean square, trefoil, coma, quatrefoil, astigmatism), and PSF remained stable (p>0.05 for all variables), while anterior and posterior elevation were significantly improved at 24 months postoperatively (p<0.001 and p=0.02, respectively). No surgical complications occurred during the 24-month follow-up.
CONCLUSION
The modified Cretan protocol is a safe and effective treatment option for PLE patients that provides visual stabilization and significant improvement in topographic parameters during the 24-month follow-up. Further studies are needed to support our results.
Topics: Humans; Retrospective Studies; Keratomileusis, Laser In Situ; Male; Female; Visual Acuity; Adult; Dilatation, Pathologic; Corneal Topography; Refraction, Ocular; Cross-Linking Reagents; Treatment Outcome; Photosensitizing Agents; Young Adult; Collagen; Lasers, Excimer; Follow-Up Studies; Riboflavin; Photochemotherapy; Corneal Diseases; Cornea; Postoperative Complications; Myopia; Ultraviolet Rays
PubMed: 38853628
DOI: 10.4274/tjo.galenos.2024.82342 -
Ophthalmology Jun 2024To assess the effectiveness and safety of repeated low-level red light (RLRL), which is a newly available treatment for myopia control in children and adolescents with...
OBJECTIVE
To assess the effectiveness and safety of repeated low-level red light (RLRL), which is a newly available treatment for myopia control in children and adolescents with high myopia.
DESIGN
Multicenter, randomized, parallel-group, single-blind clinical trial (RCT; NCT05184621).
PARTICIPANTS
Between February 2021 and April 2022, 192 children aged 6 to 16 years were enrolled. Each child had at least one eye with myopia of cycloplegic spherical equivalent refraction (SER) at least -4.0 diopters, astigmatism of 2.0 diopters or less, anisometropia of 3.0 diopters or less, and best-corrected visual acuity of 0.2 logarithm of the minimum angle of resolution or better. Follow-up was completed by April 2023.
METHODS
Participants were randomly assigned at a 1:1 ratio to intervention (RLRL treatment plus single-vision spectacles) or control (single-vision spectacles) groups. The RLRL treatment was administered for 3 minutes per session, twice daily with a minimum interval of 4 hours, 7 days per week.
MEAN OUTCOMES AND MEASURES
The primary outcome and key secondary outcome were changes in axial length and cycloplegic SER measured at baseline and the 12-month follow-up visit. Participants who had at least 1 post randomization follow-up visit were analyzed for treatment efficacy.
RESULTS
Among 192 randomized participants, 188 (97.91%) were included in the analyses (97 in the RLRL group and 95 in the control group). After 12 months, the adjusted mean change in axial length was -0.06 mm (95% confidence interval [CI]: -0.10 to -0.02 mm) and 0.34 mm (95% CI: 0.30 to 0.39 mm) in the intervention and control groups, respectively. There were 48 participants (50.3%) of the intervention group were still experiencing axial shortening more than 0.05mm at 12-month follow-up. Furthermore, the mean spherical equivalent refraction change after 12 months was 0.11 D (95% CI: 0.02 to 0.19 D) and -0.75 D (95% CI: -0.88 to -0.62 D) in the intervention and control groups, respectively.
CONCLUSIONS
RLRL demonstrates much stronger treatment efficacy among high myopia, with 50.3% experience substantial axial shortening. RLRL provides an excellent solution for the management of high myopia progression, a significant challenge in ophthalmology practice.
PubMed: 38849054
DOI: 10.1016/j.ophtha.2024.05.023 -
Journal of Refractive Surgery... May 2024To discuss factors influencing corneal aberrations that might influence the optical quality after intraocular lens (IOL) implantation. (Review)
Review
PURPOSE
To discuss factors influencing corneal aberrations that might influence the optical quality after intraocular lens (IOL) implantation.
METHODS
PubMed and Scopus were the main resources used to search the medical literature. An extensive search was performed to identify relevant articles concerning factors influencing the level of corneal aberrations as of August 27, 2023. The following keywords were used in various combinations: corneal, aberrations, defocus, astigmatism, spherical aberration, coma, trefoil, quadrafoil, intraocular lens, and IOL.
RESULTS
Conclusive evidence is lacking regarding the correlation between age and changes in corneal aberrations. Patients with astigmatism have greater corneal higher-order aberrations than those with minimal astigmatism, particularly concerning trefoil and coma. Increased levels of corneal higher-order aberrations are noted following contact lens wear, in patients with dry eye disease, and with pterygium. Increased higher-order aberrations have been reported following corneal refractive surgery and for 3 months following trabeculectomy; regarding intraocular lens surgery, the results remain controversial.
CONCLUSIONS
Several factors influence the level of corneal higher-order aberrations. Multifocal and extended depth-of-focus IOLs can share similarities in their optical properties, and the main difference arises in their design and performance with respect to spherical aberration. Preoperative evaluation is critical for proper IOL choice, particularly in corneas with risk of high levels of aberrations. .
Topics: Humans; Corneal Wavefront Aberration; Risk Factors; Lens Implantation, Intraocular; Visual Acuity; Refraction, Ocular; Multifocal Intraocular Lenses; Depth Perception; Corneal Topography; Cornea
PubMed: 38848055
DOI: 10.3928/1081597X-20240416-01 -
Heliyon Jun 2024To identify the biometric factors associated with postoperative visual performance after uneventful phacoemulsification with multifocal intraocular lens (MIOL)...
PURPOSE
To identify the biometric factors associated with postoperative visual performance after uneventful phacoemulsification with multifocal intraocular lens (MIOL) implantation.
METHODS
In this retrospective cohort study, 72 eyes of 72 patients implanted with the HumanOptics Diff-aAY MIOL were included. Preoperative examination data including the white-to-white distance (WTW), anterior chamber depth (ACD), axial length and corneal astigmatism were gathered through the electronic medical records. One month postoperatively, the pupil parameters, corneal aberrations, corneal astigmatism, IOL tilts and IOL decentrations were measured using an OPD-Scan III aberrometer. Postoperative visual performance parameters were recorded as the visual acuity, depth of focus, modulation transfer function (MTF) and point spread function (PSF) values, area under log contrast sensitivity function (AULCSF), retinal straylight and visual function questionnaire scores. Univariate and multivariate linear regression analyses were then performed to evaluate the associations between the potential biometric factors and postoperative visual outcomes.
RESULTS
Younger age predicted greater MTF and PSF values, better AULCSF and better retinal straylight (P < 0.05). A lower corneal trefoil predicted better MTF and PSF values (P < 0.05). Smaller IOL decentration predicted better distance-corrected near visual acuity, greater AULCSF and better retinal straylight (P < 0.05). A less negative spherical equivalent (SE) predicted better MTF values (P = 0.017), while a more negative SE predicted better Visual Function Index-14 (VF-14) questionnaire scores and satisfaction scores (P < 0.05). A higher IOL power predicted better best corrected distance visual acuity (P = 0.005). Lower preoperative corneal astigmatism predicted greater MTF values (P = 0.020). Lower postoperative corneal astigmatism, smaller corneal high-order aberrations (HOAs), smaller photopic pupil size, larger WTW and deeper ACD predicted a better AULCSF (P < 0.05).
CONCLUSIONS
IOL decentration, IOL power, age, preoperative and postoperative corneal astigmatism, SE, photopic pupil size, corneal trefoil, WTW, ACD and corneal HOAs were significantly associated with postoperative visual performance. These findings might aid in patient selection prior to MIOL implantation.
PubMed: 38845945
DOI: 10.1016/j.heliyon.2024.e31867 -
Frontiers in Bioengineering and... 2024This study aims to investigate the differences in binocular corneal parameters and their interrelation with binocular biometric parameters asymmetry in patients with...
PURPOSE
This study aims to investigate the differences in binocular corneal parameters and their interrelation with binocular biometric parameters asymmetry in patients with simple myopic anisometropia, thereby elucidating the influence of myopia process on various corneal parameters.
METHODS
In this cross-sectional study, 65 patients with anisometropia in monocular myopia were included. They were divided into low anisometropia group: 3.00D<Δ spherical equivalent (SE)≤-1.00D (Δ represents the difference between the two eyes, i.e., myopic data minus emmetropic data) and high anisometropia group: ΔSE ≤ -3.00D. Corneal and ocular biometric parameters were measured using Pentacam, Corvis ST, and IOL Master 700. Statistical analyses focused on the binocular corneal parameters asymmetry, using the contralateral emmetropia as a control.
RESULTS
The mean age of participants was 18.5 ± 1.3 years, with the average SE for myopia and emmetropia being -2.93 ± 1.09D and -0.16 ± 0.41D, respectively. The central corneal thickness (CCT), flat keratometry (Kf), keratometry astigmatism (Ka), total corneal aberration (6 mm) (TOA), surface variance index (ISV), vertical asymmetry index (IVA), stress-strain index (SSI), and first applanation stiffness parameter (SPA1) and ambrosia relational thickness-horizontal (ARTh) showed significant differences between anisometropic fellow eyes ( < 0.05). There were significant differences in ΔIVA, Δ the difference between the mean refractive power of the inferior and superior corneas (I-S), Δ deviation value of Belin/Ambrósio enhanced ectasia display (BAD-D), Δ deformation amplitude ratio max (2 mm) (DAR)and Δ tomographic biomechanical index (TBI) ( < 0.05) in two groups. Asymmetry of corneal parameters was correlated with asymmetry of ocular biometric parameters. Anisometropia (ΔSE) was positively correlated with ΔIVA (r = 0.255, = 0.040), ΔBAD-D (r = 0.360, = 0.006), and ΔSSI (r = 0.276, = 0.039) and negatively correlated with ΔDAR (r = -0.329, = 0.013) in multiple regression analysis. Δ mean keratometry (Km), Δ anterior chamber depth (ACD), and Δ biomechanically corrected intraocular pressure (bIOP) were also associated with binocular corneal differences.
CONCLUSION
Compared to contralateral emmetropia, myopic eyes have thinner corneas and smaller corneal astigmatism. Myopic corneas exhibit relatively more regular surface morphology but are more susceptible to deformation and possess marginally inferior biomechanical properties. In addition, there is a certain correlation between anisometropia and corneal parameter asymmetry, which would be instrumental in predicting the development of myopia.
PubMed: 38840667
DOI: 10.3389/fbioe.2024.1366408