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Indian Journal of Ophthalmology Feb 2022To primarily compare surgically induced astigmatism (SIA), total and posterior corneal curvature, pachymetry, and their stabilization after 2.2 and 2.8 mm clear corneal... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
To primarily compare surgically induced astigmatism (SIA), total and posterior corneal curvature, pachymetry, and their stabilization after 2.2 and 2.8 mm clear corneal incision in phacoemulsification.
METHODS
A randomized, prospective interventional study of 130 patients (130 eyes) of either sex having senile cataract (>40 years) divided randomly into two groups. The patients underwent uncomplicated phacoemulsification surgery with foldable intraocular lens implantation using 2.2 mm (group 1) and 2.8 mm incisions (group 2). The patients were evaluated preoperatively and followed-up at first, third, and sixth weeks.
RESULTS
Mean SIA was less in group 1 at all the follow-up visits which was not statistically significant (P value - 0.507 (at week 1), 0.626 (at week 3), and 0.312 (at week 6). Mean SIA decreased from week 1 to week 6 in both the groups. Both the groups showed an increase in SIA with the increase in the hardness of cataract. Posterior keratometry (k1 and k2) showed statistically significant steepening in the first postoperative week, followed by gradual flattening which continued till the sixth week postoperatively. Posterior astigmatism increased in both the groups at week 1 (not statistically significant). Thereafter, it decreases and does not change significantly after 3 weeks. Pachymetry increased significantly (P value < 0.001 in both the groups) in the first week in both the groups and thereafter stabilizing at 3 weeks.
CONCLUSION
Reducing the incision size does not result in any significant reduction in SIA. We observed that the posterior corneal curvature majorly stabilized by 3 weeks, but some stabilization continued till 6 weeks.
Topics: Astigmatism; Cornea; Corneal Topography; Humans; Lens Implantation, Intraocular; Phacoemulsification; Prospective Studies
PubMed: 35086206
DOI: 10.4103/ijo.IJO_882_21 -
Scientific Reports Oct 2022Bullous keratopathy (BK) is known to present with corneal edema and Descemet's folds, which can cause corneal astigmatism. However, no report quantitatively evaluated BK...
Bullous keratopathy (BK) is known to present with corneal edema and Descemet's folds, which can cause corneal astigmatism. However, no report quantitatively evaluated BK astigmatism by separating it into regular and irregular astigmatism. This study investigated the regular and irregular astigmatism of the anterior and posterior corneal surface with Fourier harmonic analysis and anterior segment optical coherence tomography. Preoperative data from 43 eyes of 41 BK patients who received corneal endothelial transplantation were compared with the data from 43 eyes of 43 subjects without corneal disease. Anterior and posterior cylinder power, central corneal thickness (CCT) and thinnest corneal thickness were significantly greater in BK. With Fourier harmonic analysis, BK eyes were found to have significantly larger anterior and posterior regular astigmatism, asymmetry component and higher-order irregularity. Asymmetry component and higher-order irregularity that accounted for the posterior irregular astigmatism increased as CCT increased in BK. Higher-order irregularity in the posterior cornea also positively correlated with worsening best corrected visual acuity. Subgroup analysis found significant correlations between CCT and posterior higher-order irregularity for intraocular surgery and laser iridotomy, but not Fuchs endothelial corneal dystrophy. This study has significance in that it revealed the characteristics of the corneal posterior irregular astigmatism of BK.
Topics: Humans; Astigmatism; Corneal Topography; Tomography, Optical Coherence; Corneal Edema; Cornea; Corneal Diseases; Fourier Analysis
PubMed: 36284222
DOI: 10.1038/s41598-022-22144-w -
Scientific Reports Jun 2021The aim of the study is to explore the distribution patterns and internal correlations of the morphological parameters of the cornea in patients with age-related... (Clinical Trial)
Clinical Trial
The aim of the study is to explore the distribution patterns and internal correlations of the morphological parameters of the cornea in patients with age-related cataract. The Pentacam HR was used to measure anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA), total corneal astigmatism (TCA) and keratometric corneal astigmatism (KCA). With age, the proportion of with-the-rule (WTR) ACA decreased from 65.31% to 23.63%, while the against-the-rule (ATR) ACA increased from 26.53% to 56.20%. PCA exceeded 0.50 D in 9.14% of eyes, while 76.35% of them were ATR. The magnitude of ACA was positively correlated with PCA in the whole sample, with a more significant correlation in WTR eyes (s = 0.349, P < 0.001). The vector summation effect of PCA to ACA changed from compensation to augmentation with aging. In 57.53% of WTR eyes, KCA was overestimated by an average of 0.21 ± 0.17 D, while it was underestimated by 0.38 ± 0.27 D in 87.62% of ATR eyes. In conclusion, among age-related cataract patients, ACA and TCA gradually shifted from WTR to ATR with aging, while most PCA remained as ATR. Ignoring the age-related changes and real PCA might cause overestimation of WTR astigmatism and underestimation of ATR astigmatism.
Topics: Adult; Aged; Aged, 80 and over; Aging; Astigmatism; Cataract; Corneal Topography; Female; Humans; Male; Middle Aged
PubMed: 34075156
DOI: 10.1038/s41598-021-91028-2 -
Journal of Refractive Surgery... Nov 2022
Topics: Humans; Astigmatism; Refraction, Ocular; Keratomileusis, Laser In Situ
PubMed: 36367270
DOI: 10.3928/1081597X-20221025-01 -
Journal of Cataract and Refractive... Mar 2022To assess the repeatability and accuracy of corneal astigmatism measurement with a spectral-domain optical coherence tomography (OCT) system (Avanti, Optovue) and... (Observational Study)
Observational Study
PURPOSE
To assess the repeatability and accuracy of corneal astigmatism measurement with a spectral-domain optical coherence tomography (OCT) system (Avanti, Optovue) and compare them with Scheimpflug imaging (Pentacam HR, Oculus) and swept-source optical biometry (IOLMaster 700, Carl Zeiss Meditec AG).
SETTING
Casey Eye Institute, Oregon Health & Science University, Portland, Oregon.
DESIGN
Prospective cross-sectional observational study.
METHODS
60 pseudophakic eyes with monofocal nontoric intraocular lens that previously had refractive surgery were analyzed. To assess accuracy, simulated keratometry (SimK) and net corneal astigmatism, obtained from each device, were compared with subjective manifest refraction astigmatism. Repeatability for corneal astigmatism was assessed for OCT and Pentacam HR by the coefficient of repeatability from 3 repeated measures.
RESULTS
Compared with manifest refraction, SimK readings produced with-the-rule astigmatic bias that was reduced for net astigmatism for the 3 devices. Except for OCT net astigmatism, all instruments significantly overestimated the magnitude of the astigmatism (linear mixed-effects model [LMM], P < .05). OCT net astigmatism showed the highest accuracy for manifest astigmatism prediction with the smaller 95% confidence ellipse for the mean difference vector. OCT net mean absolute difference was 0.57 diopters (D), significantly smaller than that of the other modalities (LMM, P < .05). Net corneal astigmatism measured with OCT showed the best repeatability (coefficient of repeatability = 0.29 D).
CONCLUSIONS
OCT has the capability to measure net corneal astigmatism with higher precision and accuracy than Pentacam HR Scheimpflug imaging and IOLMaster 700 swept-source optical biometry in postrefractive subjects.
Topics: Astigmatism; Biometry; Cornea; Corneal Topography; Cross-Sectional Studies; Humans; Prospective Studies; Reproducibility of Results; Tomography, Optical Coherence
PubMed: 34326282
DOI: 10.1097/j.jcrs.0000000000000766 -
PloS One 2021In this study, we aimed to evaluate the characteristics of astigmatism preoperatively and 1 month postoperatively in patients with age-related ptosis (AP) and contact...
In this study, we aimed to evaluate the characteristics of astigmatism preoperatively and 1 month postoperatively in patients with age-related ptosis (AP) and contact lens-related ptosis (CLP), and investigate surgery-induced astigmatism (SIA) using the Jaffe vector analysis and the Cravy method. Consecutive patients who underwent blepharoptosis surgery between January 2019 and December 2019 were included. The patients were divided into AP and CLP groups. Computerized corneal topography was used to assess the magnitude and axis of corneal astigmatism. Astigmatism was classified as with-the-rule (WTR), against-the-rule (ATR), or oblique astigmatism (OA) pre- and postoperatively. SIA was calculated by vector analysis using the Cravy and Jaffe methods. The correlation between SIA and margin reflex distance (MRD) was calculated. One hundred and eight eyes from 58 patients (AP group: 85 eyes from 45 patients, CLP group: 23 eyes from 13 patients) were included. The AP group (73.8±7.6 years) was significantly older than the CLP group (47.7±6.6 years). The MRD increased significantly after treatment in both groups. The proportions of WTR, ATR, and OA were 52%, 22%, and 25%, and 86%, 9%, and 4% in the AP and CLP groups, respectively. A shift in astigmatism type was observed in 41% and 13% of patients in the AP and CLP groups, respectively. The average SIA measured using the Cravy method was 0.11±1.22 D in the AP group and -0.28±1.07 D in the CLP group (WTR astigmatism). The SIA calculated using the Jaffe method was 0.78±0.70 D in the AP group and 0.82±0.88 D in the CLP group. There was no significant correlation between SIA calculated using the Cravy and Jaffe methods and MRD. ATR was most common in age-related ptosis and WTR was most common in contact lens-related ptosis. Upper eyelid re-positioning may affect visual functions due to astigmatic changes in the short term postoperatively.
Topics: Aged; Astigmatism; Blepharoptosis; Contact Lenses; Female; Humans; Male; Middle Aged; Postoperative Complications; Visual Acuity
PubMed: 34710107
DOI: 10.1371/journal.pone.0258688 -
The Israel Medical Association Journal... Jan 2000Previous work has suggested an association between increasing size of pterygium and increasing degrees of induced corneal astigmatism.
BACKGROUND
Previous work has suggested an association between increasing size of pterygium and increasing degrees of induced corneal astigmatism.
OBJECTIVES
To assess the quantitative relation between pterygium size and induced corneal astigmatism using a computerized corneal analysis system (TMS II) and slit-lamp beam evaluation of pterygium size, and to conclude whether corneal astigmatism is an early indication for surgical intervention.
METHODS
We evaluated 94 eyes of 94 patients with unilateral primary pterygium of different sizes, using TMS II and slit-lamp beam measurements of the size of the pterygium (in millimeters) from the limbus to assess parameters of pterygium size with induced corneal astigmatism. Best corrected visual Snellen acuity was performed.
RESULTS
Primary pterygium induced with-the-rule astigmatism. Pterygium extending > 16% of the corneal radius or 1.1 mm or less from the limbus produced increasing degrees of induced astigmatism of more than 1.0 diopter. Significant astigmatism was found in 16.16% of 24 eyes with pterygium of 0.2 up to 1.0 mm in size, in 45.45% of 22 eyes with pterygium of 1.1 up to 3.0 mm in size (P < or = 0.0004), and in 100% of 3 eyes with pterygium of 5.1 up to 6.7 mm in size (P = 0.0005). We found that visual acuity was decreased when topographic astigmatism was increased.
CONCLUSIONS
When primary pterygium reaches more than 1.0 mm in size from the limbus it induces with-the-rule significant astigmatism (> or = 1.0 diopter). This significant astigmatism tends to increase with the increasing size of the lesion. Topographic astigmatism tends to be improved by successful removal of the pterygium. These findings suggest that early surgical intervention in the pterygium may be indicated when the lesion is more than 1.0 mm in size from the limbus.
Topics: Astigmatism; Case-Control Studies; Corneal Topography; Humans; Pterygium
PubMed: 10892364
DOI: No ID Found -
Investigative Ophthalmology & Visual... Aug 2021To quantify astigmatism-related meridional anisotropy in visual resolution at central, nasal, and inferior visual fields.
PURPOSE
To quantify astigmatism-related meridional anisotropy in visual resolution at central, nasal, and inferior visual fields.
METHODS
Three groups of young adults (range, 18-30 years) with corrected-to-normal visual acuity (logMAR 0) were recruited: (1) myopic astigmats (MA): spherical-equivalent error (SE) < -0.75D, with-the-rule astigmatism ≥ 2.00D, n = 19; (2) simple myopes (SM): SE < -0.75D, astigmatism ≤ 0.50D, n = 20; and (3) emmetropes (EM): SE ± 0.50D, astigmatism ≤ 0.50D, n = 14. Resolution acuity was measured for the horizontal and vertical gratings at central and peripheral visual fields (eccentricity: 15°) using a 3-down 1-up staircase paradigm. On- and off-axis refractive errors were corrected by ophthalmic lenses.
RESULTS
The MA group exhibited meridional anisotropy preferring vertical gratings. At the central field, the MA group had better resolution acuity for vertical than horizontal gratings, and their resolution acuity for horizontal gratings was significantly worse than the SM and EM groups. At peripheral visual fields, both the SM and EM groups showed better resolution acuity for the radial (i.e., nasal field: horizontal gratings; inferior field: vertical gratings) than tangential orientation. However, the MA group tended to have better resolution acuity for the tangential orientation (i.e., vertical gratings), and their resolution acuity for horizontal gratings was significantly lower than the SM and EM groups at the nasal field. No significant differences were found in the inferior field among the three groups.
CONCLUSIONS
This study provided evidence of astigmatism-related meridional anisotropy at the fovea and nasal visual fields, underscoring the significant impact of astigmatism on orientation-dependent visual functions.
Topics: Adolescent; Adult; Anisotropy; Astigmatism; Emmetropia; Female; Fovea Centralis; Humans; Male; Myopia; Refraction, Ocular; Visual Acuity; Visual Fields; Young Adult
PubMed: 34379095
DOI: 10.1167/iovs.62.10.11 -
Indian Journal of Ophthalmology Feb 2022To compare the accuracy in astigmatism reduction by using IOLM 700 steep total keratometry (TK) axis, Berdahl and Hardten astigmatism fix, and Barrett Rx formula...
PURPOSE
To compare the accuracy in astigmatism reduction by using IOLM 700 steep total keratometry (TK) axis, Berdahl and Hardten astigmatism fix, and Barrett Rx formula following misaligned toric intraocular lens (IOL).
METHODS
Ten patients with residual refractive astigmatism due to misalignment following toric IOL implantation were included in this retrospective study. They were analyzed at days 4, 7/8, and 10/11 following primary cataract surgery on the platform of Berdahl and Hardten astigmatism fix, Barrett Rx formula, and IOLM 700 to determine the optimum axis of repositioning, and underwent IOL realignment on the steep TK axis of IOLM 700 assisted by the Callisto eye. The final outcome parameters were subjective refraction and orientation of toric IOL assessed 22 ± 1 days following repositioning surgery. These parameters were fed in the Barrett Rx formula and its vector analysis graph was utilized to determine the predicted ideal axis with the least residual astigmatism and the estimated residual astigmatism if the toric IOL was realigned according to the axis suggested by Berdahl and Hardten astigmatism fix and Barrett Rx formula.
RESULTS
Realigning the toric IOL on IOLM 700 steep TK axis along with the Callisto eye reduces the residual refractive astigmatism significantly (P = 0.003) from 2.00 ± 0.78 D to 0.18 ± 0.12 D (90.5 ± 7.6%) in comparison to the estimated 0.57 ± 0.31 D (68.4 ± 21.9%) by Berdahl and Hardten astigmatism fix and 0.61 ± 0.33 D (66.4 ± 23.5%) by Barrett Rx formula.
CONCLUSION
Realigning the misaligned toric IOL on the IOLM 700 steep TK axis gives a better reduction in the residual refractive astigmatism in comparison to Berdahl and Hardten astigmatism fix and Barrett Rx formula.
Topics: Astigmatism; Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Phacoemulsification; Refraction, Ocular; Retrospective Studies; Visual Acuity
PubMed: 35086207
DOI: 10.4103/ijo.IJO_1760_21 -
Indian Journal of Ophthalmology Dec 2021To determine the significance of any association between either change in angle kappa (Κ°) or the rectilinear displacement (L, mm) of the first Purkinje image relative...
PURPOSE
To determine the significance of any association between either change in angle kappa (Κ°) or the rectilinear displacement (L, mm) of the first Purkinje image relative to the pupil center and unexpected changes in astigmatism after phacoemulsification.
METHODS
Orbscan II (Bausch and Lomb) measurements were taken at 1, 2, and 3 months after unremarkable phacoemulsification in patients implanted with spherical (group 1, SA60AT, Alcon) or aspheric (group 2, SN60WF, Alcon) nontoric IOLs. The outputs were used to calculate L. Astigmatism, measured by autorefractometry and subjective refraction, was subjected to vector analysis (polar and cartesian formats) to determine the actual change induced over the periods 1-2 and 2-3 months postop.
RESULTS
Chief findings were that the mean (n, ±SD, 95%CI) values for L over each period were as follows: Group 1, 0.407 (38, ±0.340, 0.299-0.521), 0.315 (23, ±0.184, 0.335-0.485); Group 2, 0.442 (45, ±0.423, 0.308-0.577), 0.372 (26, ±0.244, 0.335-0.485). Differences between groups were not significant. There was a significant linear relationship between (A) the change in Κ (ΔΚ = value at 1 month-value at 2 months) and Κ at 1 month (x), where ΔΚ =0.668-3.794X (r = 0.812, n = 38, P = <0.001) in group 1 and ΔΚ = 0.263x -1.462 (r = 0.494, n = 45, P = 0.002) in group 2, (B) L and the J vector describing the actual change in astigmatism between 1 and 2 months in group 2, where J (by autorefractometry) =0.287L-0.160 (r = 0.487, n = 38, P = 0.001) and J (by subjective refraction) =0.281L-0.102 (r = 0.490, n = 38, P = 0.002), and (C) J and ΔΚ between 2 and 3 months in group 2, where J (by subjective refraction) =0.086ΔΚ-0.063 (r = 0.378, n = 26, P = 0.020).
CONCLUSION
Changes in the location of the first Purkinje image relative to the pupil center after phacoemulsification contributes to changes in refractive astigmatism. However, the relationship between the induced change in astigmatism resulting from a change in L is not straightforward.
Topics: Astigmatism; Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Phacoemulsification; Refraction, Ocular; Visual Acuity
PubMed: 34826984
DOI: 10.4103/ijo.IJO_572_21