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BMC Ophthalmology Jul 2023To evaluate the influence of decentration of plate-haptic toric intraocular lens (IOLs) on visual quality.
BACKGROUND
To evaluate the influence of decentration of plate-haptic toric intraocular lens (IOLs) on visual quality.
METHODS
This 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.
RESULTS
There 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.
CONCLUSION
The 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.
Topics: Humans; Lens Implantation, Intraocular; Astigmatism; Coma; Haptic Technology; Phacoemulsification; Lenses, Intraocular
PubMed: 37474888
DOI: 10.1186/s12886-023-03061-6 -
Clinical Ophthalmology (Auckland, N.Z.) 2023Upper tarsal mechanical forces influence corneal epithelial thickness profile, which could modulate corneal astigmatism. Upper eyelid blepharoplasty reduces upper tarsal...
INTRODUCTION
Upper tarsal mechanical forces influence corneal epithelial thickness profile, which could modulate corneal astigmatism. Upper eyelid blepharoplasty reduces upper tarsal strength and may have an impact on ocular surface. The aim of this study is to evaluate the effect of upper eyelid blepharoplasty on corneal epithelial thickness profile, astigmatism and aberrations.
METHODS
Patients with dermatochalasis underwent bilateral upper eyelid blepharoplasty. Anterior segment optical coherence tomography (AS-OCT) (Zeiss Cirrus 5000 HD-OCT) and Pentacam (Oculus, Wetzlar Germany) were performed before surgery and in the 8th postoperative week. Corneal epithelial thickness, keratometry, aberrations and asphericity were considered for statistical purposes. Only right eyes were considered. A p-value lower than 0.05 was considered significant.
RESULTS
Thirty eyes of 30 patients were included. The degree of astigmatism did not change after surgery (0.95D vs 0.83D, p=0.23). The difference between preoperative and postoperative steepest axis was 3.1° (p=0.04) with a tendency to change toward the vertical meridian. Mean epithelial thickness was higher in the inferior region both pre- and postoperatively and did not change. ET in the superior octant was lower (42 µm vs 45 µm, p<0.01) and the difference between inferior and superior octants (I-S) was higher (7 µm vs 3 µm, p<0.001) before surgery. There were no statistically significant changes in corneal aberrations (p=0.52) and asphericity (p=0.41) after surgery.
CONCLUSION
Our results support that upper tarsus pressure influences epithelial thickness profile and, consequently, the corneal steepest keratometry. These results lead us to postulate that upper eyelid blepharoplasty may influence biometric and keratometric measurements.
PubMed: 38105910
DOI: 10.2147/OPTH.S426034 -
Clinical Ophthalmology (Auckland, N.Z.) 2023To analyze different tomographic and refractive parameters for predicting successful visual outcome following femtosecond laser-assisted arcuate keratotomy (FSAK) for...
PURPOSE
To analyze different tomographic and refractive parameters for predicting successful visual outcome following femtosecond laser-assisted arcuate keratotomy (FSAK) for post-keratoplasty astigmatism.
DESIGN
Retrospective.
METHODS
Retrospective study evaluating patients with astigmatism following penetrating keratoplasty (PKP) or deep anterior lamellar keratoplasty (DALK) who underwent FSAK. Vector analysis using the Alpins method was done to calculate surgically induced astigmatism (SIA). An improvement of 3 lines of Early Treatment Diabetic Retinopathy Study (ETDRS) lines was used for successful outcome. Outcome was measured at 3 months and 17 months.
RESULTS
This study included 106 eyes from 104 patients (65 males and 39 females). Mean age was 31.8±8.6 years, and 89.4% (=93) of cases were keratoconus (KC), 3.8% (=4) scar, 3.8% (=4) granular dystrophy, 1.9% (=2) post-LASIK ectasia, and 1.0% (=1) macular dystrophy. Uncorrected visual acuity (UCVA) improved from 1.02±0.53 logarithm minimal angle of resolution (logMAR) to 0.87±0.49 logMAR (=0.01) at 3 months and to 0.92±1.08 logMAR (=0.57) at 17 months. Best spectacle-corrected visual acuity (BSCVA) improved from 0.41±0.30 logMAR to 0.31±0.19 logMAR (<0.01) at 3 months and to 0.23±0.27 logMAR (<0.01) at 17 months. Success was achieved in 50% (=53) and 49% (=52) at 3 and 17 months follow-up, respectively. Success group showed worse preoperative UCVA (1.21±0.56 vs 0.83±0.44 logMAR; <0.01), worse preoperative BSCVA (0.50±0.36 vs 0.33±0.19 logMAR; =0.01). Preoperative UCVA had an area under the curve of 0.721 (95% CI: 0.622-0.820; < 0.01). The Youden's optimal cutoff point was 0.90 logMAR (equivalent Snellen 20/159) with 76.9% sensitivity and 35.2% specificity. Flattening index (FI) was 87% in DALK and 73% in PKP (=0.14). Correction index (CI) was 99% and 86% (=0.18) for DALK and PKP, respectively. Success of the astigmatic surgery for DALK and PKP was 44% vs 42% (=0.29), respectively.
CONCLUSION
Improvement of at least three lines was achieved in 49% of patients who underwent FSAK following PKP or DALK; this improvement was achieved in patients who had a worse preoperative UCVA.
PubMed: 38089650
DOI: 10.2147/OPTH.S429264 -
Clinical Ophthalmology (Auckland, N.Z.) 2024More than 2 million implantable collamer lenses (ICLs) have been implanted worldwide. With a central port to improve aqueous flow through the ICL, the latest iteration... (Review)
Review
More than 2 million implantable collamer lenses (ICLs) have been implanted worldwide. With a central port to improve aqueous flow through the ICL, the latest iteration of this phakic intraocular lens (pIOL) has been shown to have stable outcomes with very low rates of adverse events. However, correct planning and ICL size selection continue to be important to achieve an optimal vault. Shallow or excessive vaults are not complications in and of themselves but may increase the risk of complications. Historically, surgeons have relied on measurements of anterior chamber depth (ACD) and manual, caliper-measured white-to-white (WTW) distance to select the ICL size. New diagnostic and imaging technologies such as optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM) provide additional opportunities for visualization and measurement of the intraocular dimensions involved in phakic intraocular lens implantation, including sulcus-to-sulcus (STS) and angle-to-angle (ATA) diameters. This paper reviews various approaches to ICL planning and sizing that have been published in the peer-reviewed literature, all of which produce acceptable results for predicting vault and size selection. Surgeons may also want to identify a methodology for patient evaluation and ICL size selection that best aligns with their personal preferences, diagnostic technology, and familiarity with analytical optimization tools.
PubMed: 38601168
DOI: 10.2147/OPTH.S456397 -
American Journal of Ophthalmology Apr 2024This study aimed to explore the concept of total keratometry (TK) by analyzing extensive international datasets representing diverse ethnic backgrounds. The primary...
PURPOSE
This study aimed to explore the concept of total keratometry (TK) by analyzing extensive international datasets representing diverse ethnic backgrounds. The primary objective was to quantify the disparities between traditional keratometry (K) and TK values in normal eyes and assess their impact on intraocular lens (IOL) power calculations using various formulas.
DESIGN
Retrospective multicenter intra-instrument reliability analysis.
METHODS
The study involved the analysis of biometry data collected from ten international centers across Europe, the United States, and Asia. Corneal power was expressed as equivalent power and astigmatic vector components for both K and TK values. The study assessed the influence of these differences on IOL power calculations using different formulas. The results were analyzed and plotted using Bland-Altman and double angle plots.
RESULTS
The study encompassed a total of 116,982 measurements from 57,862 right eyes and 59,120 left eyes. The analysis revealed a high level of agreement between K and TK values, with 93.98% of eyes exhibiting an absolute difference of 0.25 D or less. Astigmatism vector differences exceeding 0.25 D and 0.50 D were observed in 39.43% and 1.08% of eyes, respectively.
CONCLUSIONS
This large-scale study underscores the similarity between mean K and TK values in healthy eyes, with rare clinical implications for IOL power calculation. Noteworthy differences were observed in astigmatism values between K and TK. Future investigations should delve into the practicality of TK values for astigmatism correction and their implications for surgical outcomes.
Topics: Humans; Lenses, Intraocular; Tomography, Optical Coherence; Astigmatism; Reproducibility of Results; Cornea; Biometry; Retrospective Studies; Phacoemulsification; Refraction, Ocular
PubMed: 38092314
DOI: 10.1016/j.ajo.2023.12.003 -
Arquivos Brasileiros de Oftalmologia 2023Postoperative refraction in modern mi-croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK)...
PURPOSE
Postoperative refraction in modern mi-croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK) surgery. The surgically induced astigmatic changes in those eyes may differ not only in magnitude but also in direction compared to virgin corneas. This study aimed to compare the surgically induced astigmatic changes after microscopic cataract surgery between post-LASIK corneas and virgin eyes.
METHODS
Cases that underwent microincision cataract surgery in eyes with and without previous LASIK surgery were reviewed. The demographics, the axial length at cataract surgery, the central corneal thickness, spheric and cylindric values, keratometry readings, and postoperative posterior corneal astigmatism were retrospectively evaluated. A modified Alpins method was used for astigmatic vector analysis, and baseline astigmatism, surgically induced astigmatism, difference vector, flattening effect, and torque were assessed.
RESULTS
A total of 42 eyes from 24 subjects was evaluated. Group I consisted of 14 eyes with the previous LASIK, and Group II included 28 eyes without any refractive surgery. Preoperative mean central corneal thickness in Group I was significantly thinner (p=0.012). There was no significant difference in baseline astigmatism between the groups regarding magnitude and power vectors. After microincision cataract surgery, there were no significant differences in mean spheric and cylindric values and mean keratometry readings (all p>0.05). However, surgically induced astigmatism and difference vector were significantly higher on J45 vector component in post-LASIK eyes and microincision cataract surgery steepening effect on post-LASIK corneas was significantly higher than those in virgin eyes (p=0.001, p=0.002 and p=0.018, respectively).
CONCLUSIONS
Cataract surgery has steepened the corneas in both groups with a significantly higher steepening effect in post-LASIK eyes. Certainly, corneal topography cataract surgery is particularly helpful to provide more precise surgically induced astigmatism interpretations.
Topics: Humans; Keratomileusis, Laser In Situ; Astigmatism; Visual Acuity; Retrospective Studies; Cornea; Refraction, Ocular; Corneal Topography; Cataract
PubMed: 35544940
DOI: 10.5935/0004-2749.20230070 -
International Journal of Ophthalmology 2024To evaluate the effect of low-degree astigmatism on objective visual quality through the Optical Quality Analysis System (OQAS).
AIM
To evaluate the effect of low-degree astigmatism on objective visual quality through the Optical Quality Analysis System (OQAS).
METHODS
This study enrolled 46 participants (aged 23 to 30y, 90 eyes) with normal or corrected-to-normal vision. The cylindrical lenses (0, 0.5, 0.75, 1.0, and 1.25 D) were placed at the axial direction (180°, 45°, 90°, and 135°) in front of the eyes with the best correction to form 16 types of regular low-degree astigmatism. OQAS was used to detect the objective visual quality, recorded as the objective scattering index (OSI), OQAS values at contrasts of 100%, 20%, and 9% predictive visual acuity (OV100%, OV20%, and OV9%), modulation transfer function cut-off (MTF) and Strehl ratio (SR). The mixed effect linear model was used to compare objective visual quality differences between groups and examine associations between astigmatic magnitude and objective visual quality parameters.
RESULTS
Apparent negative relationships between the magnitude of low astigmatism and objective visual quality were observed. The increase of OSI per degree of astigmatism at 180°, 45°, 90°, and 135° axis were 0.38 (95%CI: 0.35, 0.42), 0.50 (95%CI: 0.46, 0.53), 0.49 (95%CI: 0.45, 0.54) and 0.37 (95%CI: 0.34, 0.41), respectively. The decrease of MTF per degree of astigmatism at 180°, 45°, 90°, and 135° axis were -10.30 (95%CI: -11.43, -9.16), -12.73 (95%CI: -13.62, -11.86), -12.75 (95%CI: -13.79, -11.70), and -9.97 (95%CI: -10.92, -9.03), respectively. At the same astigmatism degree, OSI at 45° and 90° axis were higher than that at 0° and 135° axis, while MTF were lower.
CONCLUSION
Low astigmatism of only 0.50 D can significantly reduce the objective visual quality.
PubMed: 38895689
DOI: 10.18240/ijo.2024.06.14 -
Journal of Refractive Surgery... May 2024To assess and compare the visual acuity and refractive outcomes of topography-guided laser in situ keratomileusis (LASIK) based on the fitting-shape-based refractive... (Randomized Controlled Trial)
Randomized Controlled Trial Comparative Study
PURPOSE
To assess and compare the visual acuity and refractive outcomes of topography-guided laser in situ keratomileusis (LASIK) based on the fitting-shape-based refractive compensated and Phorcides software strategies.
METHODS
Consecutive patients who underwent topography-guided LASIK were included in this study. Through double-masked simple randomization, patients were assigned to the Zhang & Zheng Auto-compensate Refraction (ZZ AR) group (the fitting-shape-based refractive compensated strategy using the ZZ AR calculator was used) or the Phorcides group (the topography analysis algorithm in Phorcides software [Phorcides LLC] was used). Only one eye per patient with binocular correction was randomly enrolled. The preoperative and postoperative visual acuities and refraction were analyzed at the 6-month follow-up visit.
RESULTS
The ZZ AR and Phorcides groups comprised 156 and 147 eyes, respectively. At the 6-month postoperative follow-up visit, the median (range) absolute residual cylindrical refraction was 0.35 (1.01) and 0.47 (1.63) diopters (D) for the ZZ AR and Phorcides groups, respectively ( < .001). The percentages of patients with residual cylindrical power within 0.25 D were 29.49% and 13.61% for the ZZ AR and Phorcides groups, respectively ( = .001). Based on the percentages of patients with residual cylindrical powers within 0.50 and 1.00 D, the ZZ AR group showed better outcomes ( = .02 and .01). The percentage of patients with visual acuity better than 20/16 was significantly higher for the ZZ AR group than for the Phorcides group ( = .03).
CONCLUSIONS
The fitting-shape-based refractive compensated strategy for topography-guided LASIK procedures can better optimize the visual acuity and astigmatic refraction than the Phorcides software strategy. .
Topics: Humans; Keratomileusis, Laser In Situ; Visual Acuity; Prospective Studies; Refraction, Ocular; Adult; Male; Female; Corneal Topography; Lasers, Excimer; Double-Blind Method; Myopia; Young Adult; Surgery, Computer-Assisted; Middle Aged; Cornea; Follow-Up Studies
PubMed: 38717081
DOI: 10.3928/1081597X-20240415-01