Journal ArticleDOI
Correcting astigmatism with toric intraocular lenses: Effect of posterior corneal astigmatism
TLDR
Corneal astigmatism was overestimated in WTR by all devices and underestimated in ATR by all except the Placido–dual Scheimpflug analyzer.Abstract:
Purpose To evaluate the impact of posterior corneal astigmatism on outcomes with toric intraocular lenses (IOLs). Setting Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. Design Case series. Methods Corneal astigmatism was measured using 5 devices before and 3 weeks after cataract surgery. Toric IOL alignment was recorded at surgery and at the slitlamp 3 weeks postoperatively. The actual corneal astigmatism was calculated based on refractive astigmatism 3 weeks postoperatively and the effective toric power calculated with the Holladay 2 formula. The prediction error was calculated as the difference between the astigmatism measured by each device and the actual corneal astigmatism. Vector analysis was used in all calculations. Results With the IOLMaster, Lenstar, Atlas, manual keratometer, and Galilei (combined Placido–dual Scheimpflug analyzer), the mean prediction errors (D) were, respectively, 0.59 @ 89.7, 0.48 @ 91.2, 0.51 @ 78.7, 0.62 @ 97.2, and 0.57 @ 93.9 for with-the-rule (WTR) astigmatism (60 to 120 degrees), and 0.17 @ 86.2, 0.23 @ 77.7, 0.23 @ 91.4, 0.41 @ 58.4, and 0.12 @ 7.3 for against-the-rule (ATR) astigmatism (0 to 30 degrees and 150 to 180 degrees). In the WTR eyes, there were significant WTR prediction errors (0.5 to 0.6 diopters [D]) by all devices. In ATR eyes, WTR prediction errors were 0.2 to 0.3 D by all devices except the Placido–dual Scheimpflug analyzer (all P Conclusions Corneal astigmatism was overestimated in WTR by all devices and underestimated in ATR by all except the Placido–dual Scheimpflug analyzer. A new toric IOL nomogram is proposed. Financial Disclosure Drs. Koch, Weikert, and Wang received research support from Ziemer USA, Inc. Dr. Koch has a financial interest with Alcon Laboratories, Inc., Abbott Medical Optics, Inc., Optimedica Corp., and Ziemer USA, Inc. No other author has a financial or proprietary interest in any material or method mentioned.read more
Citations
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Journal ArticleDOI
Posterior corneal astigmatism: a review article.
TL;DR: The shape and the toricity of the posterior corneal surface is reviewed and also the effect of age on it is evaluated and the accuracy of corNEal astigmatism estimation by neglecting the posterior Corneal Surface measurement is evaluated.
Book ChapterDOI
Anterior Segment OCT
TL;DR: OCT technology has been utilized successfully for anterior segment evaluation, offering several clinically relevant applications, and its capabilities allow for non-contact imaging, detailed visualization and analytics of anterior segment structures of the human eye on one device.
Journal ArticleDOI
Predictability of different calculators in the minimization of postoperative astigmatism after implantation of a toric intraocular lens.
TL;DR: The PhysIOL and the Barrett toric calculators taking into account the posterior corneal astigmatism by mathematical models, yielded lower astigmatic prediction errors compared to a standard toric calculator based on anterior keratometry data only.
Journal ArticleDOI
New algorithm for toric intraocular lens power calculation considering the posterior corneal astigmatism.
Carmen Canovas,Aixa Alarcon,Robert Rosén,Sanjeev Kasthurirangan,Joseph J.K. Ma,Douglas D. Koch,Patricia A Piers +6 more
TL;DR: The use of the new PCA algorithm decreased the error in the prediction of residual refractive astigmatism in eyes implanted with toric IOLs and led to an increased predictability of toric intraocular lens power.
Journal ArticleDOI
Toric intraocular lenses in eyes with with-the-rule, against-the-rule, and oblique astigmatism: One-year results
Yoshihiko Ninomiya,Keiichiro Minami,Kazunori Miyata,Shuichiro Eguchi,Rie Sato,Fumiki Okamoto,Tetsuro Oshika +6 more
TL;DR: Based on anterior corneal curvature alone, toric IOLs undercorrected ATR and oblique astigmatism; however, 1‐year clinical results of toric intraocular lenses were highly stable and satisfactory.
References
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Journal ArticleDOI
Contribution of posterior corneal astigmatism to total corneal astigmatism.
Douglas D. Koch,Shazia F. Ali,Mitchell P. Weikert,Mariko Shirayama,Richard B. Jenkins,Li Wang +5 more
TL;DR: Selecting toric intraocular lenses based on anterior corneal measurements could lead to overcor correction in eyes that have with‐the‐rule astigmatism and undercorrection in eyes which have against‐the-ruleAstigmatism.
Journal ArticleDOI
The shape of the anterior and posterior surface of the aging human cornea.
TL;DR: The shape of the anterior corneal surface provides no definitive basis for knowing the asphericity of the posterior surface and the results show the effective refractive index is 1.329, which is lower than values commonly used.
Journal ArticleDOI
Analysis of aggregate surgically induced refractive change, prediction error, and intraocular astigmatism
TL;DR: Analytical methods for evaluating the results of keratorefractive surgical procedures and emphasize the importance of intraocular astigmatism and the limitations of manual keratometry are demonstrated.
Journal ArticleDOI
Foldable toric intraocular lens for astigmatism correction in cataract patients.
TL;DR: The results indicate that phacoemulsification and posterior chamber AcrySof toric IOL implantation is an effective option to correct preexisting astigmatism in cataract surgery.