Postoperative Astigmatism in the Second Eye Undergoing Cataract Surgery

PurposeTo investigate the relationship between measured anterior, posterior, and total keratometric astigmatism and post-operative refractive astigmatism (RA) after cataract surgery.Patients and MethodsThis was a retrospective analysis of eyes that consecutively underwent pre-operative measurements of keratometric astigmatism with a swept-source optical coherence tomography (SS-OCT)-based optical biometer and dual-Scheimpflug/Placido disc corneal topographer, cataract surgery with implantation of a monofocal intraocular lens, and post-operative manifest refraction. The difference between post-operative refractive astigmatism and keratometric astigmatism measured using four different ways [Keratometry (K), Simulated Keratometry (SimK), Total Keratometry (TK), and Total Corneal Power (TCP)] was calculated.ResultsFor all 118 eyes, a smaller mean vector difference between post-operative refractive astigmatism and measured keratometric astigmatism was realized with TK (0.08 @ 151) vs TCP2 (0.30 @ 174; p < 0.0006), as well as with K (0.26 @ 173) vs SimK (0.52 @ 177; p = 0.036). The mean vector difference between post-operative refractive astigmatism and TK astigmatism was 0.31 @ 097, 0.21 @ 163, and 0.69 @ 179 in eyes with against-the rule (ATR), oblique, and with-the-rule (WTR) anterior corneal astigmatism, respectively (p < 0.0006). On the other hand, posterior corneal astigmatism did not significantly change with the orientation of anterior corneal astigmatism [0.10 @ 180 for ATR, 0.22 @ 180 for oblique, and 0.28 @ 180 for WTR (p = 0.58)].ConclusionCompared with the other measures of corneal astigmatism, total keratometric astigmatism from the SS-OCT device most closely correlated with post-operative RA. The difference between anterior corneal astigmatism and refractive astigmatism is not completely explained by the contribution from the posterior cornea. Other contributors, such as lens tilt or neuro-adaptation, may be at play.

BackgroundTo examine the influence of posterior corneal astigmatism on postoperative refractive astigmatism in pseudophakic eyes after cataract surgery.MethodsThe study enrolled 64 pseudophakic eyes of 50 patients (71.8 ± 9.9 years old, mean ± standard deviation) who had undergone phacoemulsification with non-toric IOL implantation. Refractive astigmatism was measured using an auto ref-keratometer with a 0.01- diopter (D) scale. Two types of corneal astigmatism were calculated using anterior segment optical coherence tomography; keratometric and total corneal astigmatism. Keratometric astigmatism was obtained based on anterior corneal curvature alone and total corneal astigmatism was calculated using both anterior and posterior corneal curvatures. The difference between refractive and corneal astigmatism was computed as the vector difference using 1) refractive and keratometric astigmatism and 2) refractive and total corneal astigmatism.ResultsThe mean refractive, keratometric, and total corneal astigmatism was 0.92 ± 0.48 D, 0.87 ± 0.44 D, and 0.94 ± 0.46 D, respectively. The difference between refractive and keratometric astigmatism (0.70 ± 0.40 D, mean vector of 0.30 D axis 164°) was significantly larger than the difference between refractive and total corneal astigmatism (0.63 ± 0.38 D, mean vector of 0.12 D axis 137°) (P = .019).ConclusionsThe difference between refractive and total corneal astigmatism, calculated using both anterior and posterior corneal curvatures, was significantly smaller than the difference between refractive and keratometric astigmatism using anterior corneal astigmatism alone, implying that the latter overestimates the true postoperative refractive astigmatism and can cause cylindrical inaccuracy after cataract surgery.

Flattening effect is the key parameter for toric calculator

To evaluate safety, efficacy, ergonomy, and refractive and keratometric stability in high myopia LASIK procedures using a novel femtosecond and excimer laser surgery platform. One hundred sixteen eyes in consecutive cases of high myopic LASIK ( ≥ -6.00 diopters [D]) with the Alcon-WaveLight FS200 femtosecond and EX500 excimer lasers (Alcon Laboratories, Fort Worth, TX) were evaluated preoperatively and postoperatively for the following parameters: refractive error, corrected distance visual acuity, uncorrected distance visual acuity, spherical equivalent correction, keratometry (with Placido topography and Scheimpflug tomography), and refractive astigmatism. Average follow-up time was 6.2 months (range: 3 to 12 months). Postoperative average refractive error was -0.37, -0.43, and -0.25 D for the 3-, 6-, and 12-month period, compared to -7.67 ± 1.55 D preoperatively. At 3, 6, and 12 months postoperatively 94%, 96.3%, and 100% of eyes, respectively, were within 1.0 D defocus equivalent. Postoperative refractive astigmatism was -0.21, -0.21, -0.13 D for the 3-, 6-, and 12-month period compared to -1.07 ± 1.91 D preoperatively. The proportion of eyes with postoperative astigmatism within 0.25 D was 85.3%, 81.5%, and 100%, for the 3-, 6-, and 12-month visit, respectively. Keratometric stability was within 0.22 D after the 12-month visit. There was no epithelial ingrowth or diffuse lamellar keratitis in any case. Clinical outcomes with this technique and technology appear to be promising in high level uncorrected visual rehabilitation of high myopia. There was small regression potential in the sample evaluated.

To analyze the effectiveness and safety of corneal relaxing incisions (CRI) in correcting keratometric astigmatism during cataract surgery. A prospective study of two groups: control group and treatment group. A treatment group included 25 eyes of 25 patients who had combined clear corneal phacoemulsification, IOL implantation and CRI. A control group included 25 eyes of 25 patients who had clear corneal phacoemulsification and IOL implantation. Postoperative keratometric astigmatism was measured at 1 week, 1 month, 3 months and 6 months. CRI significantly decreased keratometric astigmatism in patients with preexisting astigmatism compared with astigmatic changes in the control group. In eyes with CRI, the mean keratometric astigmatism was 0.29+/-0.17 D (range 0 to 0.5 D) at 1 week, 0.41+/-0.21 D (range 0 to 0.82 D) at 1 month, respectively reduced by 2.42 D and 2.30 D at 1 week and 1 month postoperatively (P=0.000, P=0.000), and postoperative astigmatism was stable until 6 months follow-up. The keratometric astigmatism of all patients decreased to less than 1.00 D postoperatively. CRI is a practical, simple, safe and effective method to reduce preexisting astigmatism during cataract surgery. A modified nomogram is proposed. The long-term effect of CRI should be investigated.

To compare the prediction accuracy of toric intraocular lens calculations using estimated vs measured posterior corneal astigmatism (PCA). Retrospective case series. A total of 110 eyes of 110 patients with uncomplicated toric intraocular lens implantation were included in this study. Predicted postoperative refractive astigmatism was calculated with the Barrett Toric Calculator using the estimated PCA (E-PCA), the measured IOLMaster 700 PCA (I-PCA), and the measured Pentacam PCA (P-PCA). Refractive astigmatism prediction errors (RA-PEs), including their trimmed (tr-) centroid (mean vector), spread (precision), tr-mean absolute RA-PE (accuracy), and percentage within a certain threshold, were determined using vector analysis and compared between groups. University Eye Clinic, Maastricht University Medical Center+, the Netherlands. The tr-centroid RA-PEs of the E-PCA (0.02 diopter [D] at 82.2°), the I-PCA (0.08 D at 35.5°), and the P-PCA (0.09 D at 69.1°) were significantly different from each other (P < .01), but not significantly different from zero (P = .75, P = .05, and P = .05, respectively). The E-PCA had the best precision (tr-mean 0.40 D), which was not significantly lower than the I-PCA (0.42 D, P = .53) and P-PCA (0.43 D, P = .06). The E-PCA also had the best accuracy (0.40 D), which was not significantly different from the I-PCA (0.42 D, P = .26) and significantly better than the P-PCA (0.44 D, P < .01). The precision and accuracy of the I-PCA did not significantly differ from those of the P-PCA. There were no statistically significant differences in the percentage of eyes within a certain absolute RA-PE threshold. The Barrett Toric Calculator using the E-PCA, I-PCA, or P-PCA showed a comparable prediction of postoperative refractive astigmatism in standard clinical practice.

To report the clinical outcomes of patients who underwent cataract surgery with implantation of Ankoris monofocal toric intraocular lens (IOL) (PhysIOL SA, Liège, Belgium) using the Zeiss Callisto Eye (Carl Zeiss AG, Dublin, CA). We conducted a retrospective case series of patients who underwent routine cataract extraction and implantation of Ankoris toric IOL using the Zeiss Callisto eye between January 2018 and December 2018 by four senior surgeons. Patients' medical records were reviewed, and clinical outcomes including postoperative refraction, visual acuity outcomes, IOL position and deviation from planned axis were collected. Fifty-six eyes of 56 patients were included, 48% were female, and the mean age was 70 ± 8years. Patients with pseudoexfoliation syndrome, glaucoma or keratoconus were excluded from the study. Pre-operative mean corneal astigmatism was 2.38 ± 0.78 diopters (D), and mean implanted IOL cylindrical power was 3.06 ± 1.07 D. IOL rotation 30days postoperatively was within 5° in 82% of eyes and between 6° and 10° in 10.8% of eyes. Mean postoperative refractive astigmatism 30days postoperatively was 0.22 ± 0.36D; in 84% of eyes the postoperative refractive astigmatism was ≤ 0.50D. IOL rotation significantly increased between day 1 to day 7 postoperatively (1.91 ± 3.15° to 3.18 ± 3.3°, P = 0.001). However, no significant rotation had occurred between day 7 and day 30 postoperatively (P = 0.093). Cataract surgery with implantation of Ankoris monofocal toric IOL using the Zeiss Callisto Eye marking system is predictable and effective in reducing refractive astigmatism.

Refractive surprise after phacoemulsification in a post-laser in situ keratomileusis case: December consultation #1

The effects of surgical factors on postoperative astigmatism in patients enrolled in the Infant Aphakia Treatment Study (IATS)

The purpose of this review is to evaluate the prediction of postoperative residual astigmatism and to determine the best prediction method for astigmatism correction. In recent findings for residual astigmatism in non-toric monofocal intraocular lens (IOL) implanted eyes, vector analysis can be used to correctly evaluate residual astigmatism by decomposing it. In predicting residual astigmatism, the with-the-rule (WTR) and against-the-rule (ATR) astigmatism components can now be almost predicted. This may be due to advances in inspection equipment and surgical technique. However, there are still issues with the oblique astigmatism component. In addition, corneal astigmatism is the most important predictor of postoperative residual astigmatism, and other predictors, such as refractive astigmatism, age, and lens thickness, have also been mentioned. However, all but corneal astigmatism are questionable because of the possibility of confounding variables. Total corneal astigmatism is more accurate in predicting residual astigmatism than anterior corneal astigmatism. Several predictions of residual astigmatism have been reported, but complete prediction has not been possible. Further research is needed, especially in predicting oblique astigmatism. However, I emphasize that the accuracy of predicting WTR and ATR astigmatism has improved considerably and can be predicted using regression equations with total corneal astigmatism.

this small study relates our early experiences with the Limbal Relaxing Incision (LRI) for management of astigmatism in patients undergoing cataract surgery. to evaluate the efficacy of LRI in the management of primary astigmatism when combined with phacoemulsification. limbal relaxing incisions were performed to correct primary astigmatism in 12 eyes of 12 cataract patients who underwent phacoemulsification as the primary procedure. The length and number of incisions were determined using the AMO LRI calculator software programme using Donnenfield and NAPA nomograms. Keratometric astigmatism was measured preoperatively and postoperatively on day 1 and after 3 weeks or more. Surgically-induced astigmatism (SIA) and the intended angle of error were evaluated by the vector analysis method. Preoperative and postoperative uncorrected visual acuity (UCVA) and best spectacle corrected visual acuity (BSCVA) were evaluated in each visit. The mean age of patients was 52.92 +/- 10.91 years. There were 75 % male and 25 % female patients. The mean keratometric preoperative astigmatism was 2.08 +/- 1.05 diopter. The mean 1st postoperative day keratometric astigmatism was 1.74 +/- 1.32 diopter and the mean final keratometric astigmatism at 3 weeks postoperatively was 1.05 +/- 0.68 diopter. The mean SIA on the 1st postoperative day was 2.97 +/- 1.72 diopter at 103.25 +/- 56.57 degree with intended angle of error 6.53 +/- 9.61 degree. The mean SIA on the 3rd postoperative week was 2.26 +/- 0.87 Diopter at 107.08 +/- 49.96 degrees with intended angle of error 2.90 +/- 7.87 degrees. limbal relaxing incisions are effective method to reduce postoperative astigmatism with good predictability of intended angle.

To investigate whether the magnitude of posterior corneal astigmatism (PCA) impacts refractive and visual outcomes of primary topography-guided laser in situ keratomileusis (LASIK) and to provide guidance on treating eyes with high PCA. Comparative retrospective analysis of 4,541 consecutive eyes treated with Contoura (Alcon Laboratories, Inc) on the manifest refractive astigmatism. Standard outcomes of the 1,514 eyes with the lowest PCA (first tercile; low PCA group) were compared to the 1,514 eyes with the highest PCA (last tercile; high PCA group). Pearson correlation coefficient was used to assess relationships between variables. Preoperatively, 20.9% of eyes presented with PCA of 0.50 diopters (D) or greater. The mean PCA was 0.18 ± 0.07 D in eyes with low PCA, and 0.50 ± 0.11 D in eyes with high PCA. An equivalent number of eyes achieved a cumulative postoperative unilateral uncorrected distance visual acuity of 20/20 in both the low PCA and high PCA groups (95.3% vs 94.7%; P = .4489). The efficacy index of both low and high PCA eyes was identical (0.99 ± 0.06 vs 0.99 ± 0.08; P = .3192), as was the safety index (1.00 ± 0.02 vs 1.00 ± 0.03; P = .0110). The magnitude of preoperative PCA was weakly correlated with postoperative refractive astigmatism (R = 0.1323), but not with postoperative defocus equivalent (R = -0.0414) or spherical equivalent (R = -0.0128). PCA does not negatively impact the outcomes of topography-guided LASIK targeting the manifest refraction, having identical accuracy, efficacy, and safety in eyes with both low and high PCA. There is no scientific basis to measure and consider PCA in topography-guided LASIK planning software or nomograms if the excimer laser treatment input targets the manifest refraction. [J Refract Surg. 2022;38(12):780-790.].

To evaluate the preliminary visual results of femtosecond laser-assisted Descemet stripping endothelial keratoplasty (FS-DSEK). We prospectively analyzed results of 20 consecutive patients with Fuchs endothelial dystrophy or aphakic/pseudophakic bullous keratopathy who underwent FS-DSEK. Best spectacle-corrected visual acuity (BSCVA), refraction, corneal topography, and endothelial cell density were measured preoperatively and 3 and 6 months after FS-DSEK. Corneal thickness was measured using an optical coherence tomography technique. The average BSCVA of 11 eyes with normal visual potential significantly improved from 20/110 +/- 4 lines to 20/57 +/- 1 line at 6 months (P < .007). At 6 months, the mean (SD) hyperopic shift was 2.24 (2.3) diopters (D). Preoperative and 6 months postoperative refractive astigmatism were -0.75 (0.9) D and -1.58 (1.1) D (P = .01), but the topographic astigmatism did not change postoperatively (P = .95). Mean (SD) endothelial cell density at 6 months was 1368 (425) cells/mm(2). There was a persistent deswelling of the graft up to 3 months postoperatively. Complications included graft dislocations requiring repositioning (20%), pupillary block glaucoma (5%), epithelial ingrowth (5%), and primary graft failure (5%). Femtosecond laser-assisted Descemet stripping endothelial keratoplasty was effective in treating endothelial failure with minimal induced refractive astigmatism, limited improvement of BSCVA, and induction of a hyperopic shift. Endothelial cell count and dislocation rate were significant, which may be related to the surgical technique.

Comparison of refractive and keratometric astigmatism after microincision cataract surgery

Introduction Blindness due to cataract presents an enormous problem especially in developing countries like India, not only in terms of human morbidity but also in terms of economic loss and social burden. The cataract surgeon of today is challenged to control the sphere as well as the cylinder of the refraction after surgery. Small incision cataract surgery (SICS) is now the method of choice in many parts of the world. This present study has been carried out with the aim to compare the postoperative corneal astigmatism between the two groups of patients undergoing SICS with posterior chamber intraocular lens (PCIOL) implantation with two difference types of incisions, i.e., frown and straight. Material and methods A prospective study was carried out in 60 patients enrolled from the Department of Ophthalmology of Pondicherry Institute of Medical Sciences who underwent SICS with superiorly placed straight and frown incision with PCIOL (each group consisting of 30 patients) during the period from May 2005 to October 2006. Results In this study, 60 patients having senile cataract in the age group of 50 to 75 years were studied. Out of these, the majority were in the age group of 60 to 64 (28.33%) years and only 26.66% were more than 70 years. The male:female ratio was 1:1. In our study, we found that frown incision had significantly better (p &lt; 0.001) mean net astigmatism as compared with the straight incision. Conclusion We conclude that small incision size and absence of suture are the most important factors that contribute to less astigmatism and faster stabilization of SICS, where phacoemulsification cannot be performed. The duration for stabilization of postoperative astigmatism in straight incision group is 6 weeks, whereas it is 3 weeks in frown incision. Frown superior incision has got added advantage of early wound stabilization than straight incision, allowing the patient to resume their daily activities at an early stage. Superior incision group (both frown and straight) had increased amount of with-the-rule (WTR) astigmatism which later shifted to against-the-rule. There was a significant difference in net astigmatism between frown and straight. Postoperative astigmatism also depends on preoperative astigmatism. Patients with preoperative WTR benefited from superior incision cataract surgery. How to cite this article Tripathi S, Srinivasan M, Gupta S. Astigmatism in Straight and Frown Incision in Small Incision Cataract Surgery: A Comparative Study. Int J Adv Integ Med Sci 2017;2(3):111-116.