EyeWorld India March 2013 Issue

11 March 2013 EWAP FEATURE automated keratometry, there’s often greater ability to duplicate results. For looking at the direction of the astigmatism, however, topography tends to be best. “If there is a lot of disagreement typically what I’ll do is use automated or manual keratometry to determine magnitude and then use the topography to look at the direction of the cylinder,” he said. Going forward, Dr. Holladay believes that intraoperative aberrometry will become the standard of care in the future enabling practitioners to better achieve the target of emmetropia without astigmatism and possibly other higher aberrations such as spherical aberration and coma. Ultimately this will enable practitioners to put patients within 1/8 of a diopter of spheroequivalent target, the limit of IOLs available in 0.50 D increments, without any residual astigmatism or higher- order aberrations. “When we do that we’ll have a large number of patients, more than 70%, that are much better than 20/20 because the studies show that approximately 90% of the cataract age group has the neurological and retinal function that is as good as the vision as when they were 19 years old,” he said. EWAP Editors’ note: Dr. Holladay has financial interests with Alcon, AMO, WaveTec, and Oculus. Dr. Lane has financial interests with Alcon and WaveTec. Dr. Trattler has financial interests with AMO and Oculus. Contact information Holladay: 713-669-8977, holladay@docholladay.com Lane: 651-275-3000, sslane@associatedeyecare.com Trattler: 305-598-2020, wtrattler@gmail.com OCULUS Asia Ltd. Hong Kong Tel. +852 2987 1050 • Fax +852 2987 1090 www.oculus.de • info@oculus.hk OCULUS Pentacam ® HR The new Belin / Ambrosio Display III: Unique for Keratoconus and Ectasia Detection Based on Corneal Tomography Combination of 5 corneal elevation and pachy- metry parameters into one final overall index for quick visual inspection for quick decision making comprehensive but intuitive ONLY available for Pentacam ® ! database for hyperopic patients novel pachymetric parameter ARTmax • • • • • Views from Asia-Pacific Yi LU, MD Director, Department of Ophthalmology, Eye & ENT Hospital of Fudan University 83 Fenyang Road, Shanghai 200031, China Tel. no. +86-21-64377134-407 Fax no. +86-21-64318258 Luyi0705@yahoo.com.cn N owadays, I agree that attention should be paid to astigmatism correction for cataract surgery in a more comprehensive way, such as taking the posterior surface of the cornea into consideration. Actually, for the eye as a whole, astigmatism, as a lower-order aberration, has a much greater impact on the visual function than higher-order aberrations such as spherical aberration, so that the correction of spherical aberration should be based on the full correction of astigmatism. To correct astigmatism accurately, precise measurement is the prerequisite. However, regarding the selection of instruments, there is no gold standard for the evaluation of preoperative astigmatism in cataract patients at this moment. Since each instrument possesses its pros and cons, establishing the optimal measuring approach still requires the support of rigorous randomized controlled trials. And these approaches will constantly be improved in subsequent practice. In fact, if simply considering correcting corneal astigmatism in cataract surgery, Pentacam is better than either the OPDscan or IOLMaster because it measures more corneal points, and it can measure both anterior and posterior corneal surfaces, as well as recognize irregular astigmatism and keratoconus; if both astigmatism and spherical aberration are aimed to be corrected during the surgery, devices that can analyze a combination of topography and wavefront measurements at the same time might be a better choice, such as OPDscan. However, as for those intraoperative measuring equipment mentioned in this article, such as the ORA or Clarity, I am worried that although they can provide timely monitoring of astigmatism, they neglect the importance of surgically induced astigmatism (SIA). If the surgical design is based on these data, one would expect error in the final result due to postoperative corneal incision reconstruction. Therefore, before the gold standard is established, I suggest that every practitioner evaluate his or her personal SIA precisely, and assess preoperative astigmatism carefully using advanced equipment such as the Pentacam in order to establish a rational surgical plan. Editors’ note: Dr. Lu has no financial interests related to his comments.