Accuracy and precision of OCT derived net corneal astigmatism in pseudophakic eyes with nontoric intraocular lens
0
Citation
0
Reference
20
Related Paper
Keywords:
Astigmatism
Cite
Objective:To investigate the preoperative corneal astigmatic nature and extent of postoperative corneal astigmatism,tendency and strength in order to take the best of corneal incision and implantation of toric intraocular lens,maximumly reduce corneal astigmatism,allow patients to obtain better uncorrected vision. Methods: 110 patients were chosen from in line with the conditions of the 170 eyes including 90 eyes in male,80 in female eyes, aged from 50 to 89 years, with IOLMater measurements for each patient's corneal curvature.Corneal curvature, corneal astigmatism and axial were drew from average corneal curvature in measured three times in which the corneal astigmatism axis and corneal astigmatism value differences were statistically analyzed in order to guide the operation selection of corneal incision direction and crystal selection. Results: With the increase of age,the corneal astigmatism axial was tendency from with-the-rule aptitude against the rule of change (P0.001).Understanding the axis of astigmatism and the degree of astigmatism can better guide the choice of operation incision direction and choice of intraocular lens astigmatism. Conclusion: Preoperative accurate measurement of corneal curvature,understanding of astigmatism axis and astigmatism have the guide significance in cataract operation.
Astigmatism
Cite
Citations (0)
We report the case of a 49-year-old patient with megalocornea and coexisting corneal astigmatism. The corneal diameter in the right eye was 15.0 mm and in the left eye, 14.9 mm. In both eyes, a nuclear sclerotic cataract developed, with the tendency toward cortical mass swelling in the right eye. The aim of surgical treatment was to remove the cataract with simultaneous correction of corneal astigmatism by implanting an Acrysof toric intraocular lens (IOL). Intraocular lens stabilization was obtained by suturing it to an capsular tension ring (CTR) in the anterior chamber. The IOL-CTR complex was rotated into the lens capsule and aligned with the steep meridian of corneal astigmatism. The surgical technique provides a stable refractive and functional effect in patients with megalocornea and coexisting cataract and corneal astigmatism.
Astigmatism
Intraocular lenses
Cite
Citations (15)
Astigmatism
Cite
Citations (7)
To evaluate the accuracy of preoperative keratometers used in cataract surgery with toric intraocular lens (IOL).Twenty-five eyes received an AcrySof toric IOL implantation. Four different keratometric methods, a manual keratometer, an IOL master, a Pentacam and an auto keratometer, were performed preoperatively in order to evaluate preexisting corneal astigmatism. Differences between the true residual astigmatism and the anticipated residual astigmatism (keratometric error) were compared at one and three months after surgery by using a separate vector analysis to identify the keratometric method that provided the highest accuracy for astigmatism control.The mean keratomeric error was 0.52 diopters (0.17-1.17) for the manual keratometer, 0.62 (0-1.31) for the IOL master, 0.69 (0.08-1.92) for the Pentacam, and 0.59 (0.08-0.94) for the auto keratometer. The manual keratometer was the most accurate, although there was no significant difference between the keratometers (p > 0.05). All of the keratometers achieved an average keratometric error of less than one diopter.Manual keratometry was the most accurate of the four methods evaluated, although the other techniques were equally satisfactory in determining corneal astigmatism.
Astigmatism
Cite
Citations (40)
PURPOSE: To evaluate the influencing factors on remaining astigmatism after implanting a toric intraocular lens during cataract surgery. METHODS: In this observational study, consecutive patients with cataract from three different centers who received toric intraocular lenses were included. Keratometry was performed with an optical biometry device preoperatively. The IOLMaster 500 (Carl Zeiss Meditec AG, Jena, Germany) was used in Vienna, Lenstar (Haag-Streit, Köniz, Switzerland) in Castrop-Rauxel, and IOLMaster (Carl Zeiss Meditec AG) in London. Partial least squares regression was used to detect the influence of different parameters on remaining astigmatism. RESULTS: In total, 235 eyes of 200 patients were included. Mean corneal astigmatism measured preoperatively with the optical biometry device was −2.24 ± 0.87 diopters (D) (range: −5.75 to −1.00 D). Mean absolute and vector difference between the aimed for and the postoperatively measured astigmatism were 0.48 ± 0.37 D (range: 0.00 to 2.05 D) and 0.73 ± 0.46 D (range: 0.031 to −2.20 D), respectively ( P = .576). Partial least squares regression showed a significant effect of preoperatively measured corneal astigmatism and deviation between preoperative measurements of the cornea on the postoperative (unintended) remaining astigmatism. CONCLUSIONS: The main source of error when using toric intraocular lenses is the preoperative measurement of corneal astigmatism, especially in eyes with low astigmatism. The influence of the postoperative anterior chamber depth on the cylindrical power of toric intraocular lenses and the effect of misalignment on the reduction of the astigmatism-reducing effect can be easily calculated. [ J Refract Surg. 2014;30(6):394–400.]
Astigmatism
Cite
Citations (61)
Corneal astigmatism is a common refractive error observed in a significant percentage of cataract patients. Accurate measurements of the preexisting corneal astigmatism are essential in order to achieve the desired refractive outcome after toric intraocular lens (IOL) implantation. This article presents a comprehensive review of recent published literatures on methods for measuring preoperative corneal astigmatism for toric IOL implantation.A variety of instruments has been introduced and used to measure the magnitude and meridian of corneal astigmatism during preoperative assessments of cataract patients. Instruments that consider both the anterior and posterior corneal surfaces as critical factors for measuring total corneal astigmatism are expected to provide better accuracy. Although these instruments facilitate improved evaluations of corneal astigmatism and have helped minimize postoperative residual astigmatism, a perfect method to analyze preoperative corneal astigmatism has not yet been established.Perfect correction of astigmatism after toric IOL implantation by using accurate corneal astigmatism values is the goal of this surgical procedure. To achieve this, correct and precise measurements of corneal astigmatism to determine the magnitude and meridian should be obtained.
Meridian (astronomy)
Astigmatism
Cite
Citations (29)
Purpose: To report the clinical efficacy of astigmatism correction with toric intraocular lenses (IOLs) in patients undergoing the Descemet membrane endothelial keratoplasty (DMEK) triple procedure and to evaluate the accuracy of the correction. Methods: Fifteen eyes of 10 patients who received cataract extraction, toric IOL placement, and DMEK surgery for Fuchs corneal dystrophy and cataracts were evaluated. The cylinder power of toric IOLs was determined by an online toric calculator with keratoscopy measurements obtained using Scheimpflug corneal imaging. Prediction errors were assessed as a difference vector between the anticipated minus postoperative residual astigmatism. Results: At 10.1 ± 4.9 months postoperatively, 8/13 (61.5%) of eyes achieved uncorrected distance visual acuity better than 20/40. Mean best spectacle-corrected distance visual acuity (logMAR) improved from 0.21 ± 0.15 preoperatively to 0.08 ± 0.12 postoperatively ( P < 0.01). The magnitude of refractive astigmatism was also significantly decreased from 2.23 ± 1.10 D (range 0.75–4.25 D) preoperatively to 0.87 ± 0.75 D (range 0.00–3.00 D) postoperatively ( P < 0.01). In 1 eye with rotational misalignment by 43 degrees, we found no improvement of astigmatism. The prediction error of astigmatism at the corneal plane was 0.77 ± 0.54 D (range 0.10–1.77 D). Four eyes with preoperative “with-the-rule” corneal astigmatism had postoperative “against-the-rule” refractive astigmatism. Conclusions: For patients with Fuchs corneal dystrophy and cataracts, use of toric IOLs might be a valuable option in triple DMEK surgery. Additionally, care should be taken to prevent excessive IOL rotation.
Astigmatism
Scheimpflug principle
Cite
Citations (30)
Objective To evaluate the refractive and visual outcome of Toric IOL implantation for correction of pre-existing corneal astigmatism following cataract surgery.Methods 32 eyes of 23 patients were undergone implantation of Toric IOL following regular phacoemulsification.Pre-and post-operative corneal and refractive astigmatisms,and post-operative distance vision were investigated.Statistical analysis was carried out using the paired student t-test when necessary.Results No statistical difference was observed between pre-and post-operative corneal astigmatism(P0.05).Postoperative refractive astigmatism was significantly less(P0.05).The IOLs in 31 eyes rotated less than 5 degrees in 3 month postoperatively.Conclusion Toric IOL implantation is a viable and highly predictable method of correcting the corneal astigmatism.It allows correction without compromising the integrity of the cornea.
Astigmatism
Intraocular lenses
Cite
Citations (0)
Astigmatism
Cite
Citations (1)
Purpose: To assess the accuracy of toric intraocular lens (IOL) implantation by the location and size of the corneal incision.Methods: We retrospectively reviewed the medical records of 98 patients (98 eyes) who underwent phacoemulsification with toric IOL implantation from January 2014 to March 2017.The patients were divided into two groups: group 1 got an incision of the superior side of the cornea (n = 54) and group 2 received an incision on the temporal side of the eye (n = 44).For both groups, incisions were made at their steep corneal astigmatism axises.Each group was further divided into subgroups for whom different sized blades were employed (2.75 vs. 2.2 mm widths).We measured the refractive index and autokeratometric parameters.We postoperatively assessed residual astigmatism and any reduction thereof.Results: In both groups, uncorrected and best-corrected visual acuity, refraction cylinder astigmatism, and autokeratometric astigmatism improved statistically.Between two groups, corneal astigmatism decrease was not significant.Residual astigmatism also showed no significant differences between the two.Patients in both groups treated using 2.75 mm wide blades exhibited greater increases in corneal astigmatism.Conclusions: During cataract surgery, precise correction of astigmatism via toric IOL implantation is possible when surgically induced astigmatism is minimized by careful choice of the location and size of the corneal incision.
Astigmatism
Position (finance)
Cite
Citations (0)