Carlos Emiliano Rodriguez Lopez, Guadalupe Fernando Mora González, Jorge Rendón Félix, Gerardo Daniel Jáuregui García, Miguel Angel Ibañez Hernández Pan Am J Ophthalmol 2020, 2:23 (19 August 2020) DOI:10.4103/PAJO.PAJO_28_20
Background: More than 50% of patients undergoing cataract surgery have corneal astigmatism ≥ 0.75 diopters (D). A fundamental factor for the calculation of the intraocular lens (IOL) is the power of corneal refraction, which can be calculated with different methods and incorporated into different mathematical prediction models. Little information has been written comparing new formulas that take into account posterior keratometry.
Aims and Objectives: Compare the prediction of the ideal IOL with different formulas that use anterior keratometry and posterior keratometry measured by different devices.
Setting: Private practice, Guadalajara, Jalisco, Mexico.
Materials and Methods: A descriptive, observational and retrospective study was carried out where 50 healthy eyes with cataract and a degree of corneal astigmatism >1 D were evaluated, IOL calculation was compared using the anterior and total keratometries measured with the Zeiss IOL master 700 and the total corneal refractive power (TCRP) keratometries of the Oculus Pentacam. The results were also compared with the Haigis Suite, Barrett TK and Z Calc formulas. The IOL used for the analysis was the Zeiss AT TORBI 709M/MP.
Results: It was found that the different formulas can generate different predictions in the cylinder power but no significant differences in the sphere power. Measurement of the posterior cornea did not significantly change the selection of the ideal IOL for implantation. Calculations with Haigis Suite and Z Calc are very similar. Barrett TK-Toric uses less cylindrical power than Haigis Suite and Z calc, regardless of the method chosen to measure corneal power.
Conclusion: Our results contribute to clarify the current scenario where the great variety of options for the calculation of IOL generates uncertainty about which method generates better results of postoperative refraction.
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Natalia Espinosa, Ivon Pinto, Alejandro Arias, Laura Toro, Juan DiazGranados, Adriana Solano Pan Am J Ophthalmol 2020, 2:21 (19 August 2020) DOI:10.4103/PAJO.PAJO_4_20
Purpose: The purpose was to describe the changes in the visual function of patients with cataract, optic neuritis, amblyopia, and retinopathies evaluated at the Hospital de San José, Bogotá, Colombia, between August 2015 and May 2019.
Materials and Methods: This is a descriptive cross-sectional study. One hundred and ninety-six patients with a diagnosis of cataract, retinopathies, optic neuritis, and amblyopia were evaluated; the tests were performed to determine the visual function (visual acuity, stereopsis, contrast sensitivity, and color tests). Qualitative and quantitative characteristics were described.
Results: Of the 196 patients, 17.3% had amblyopia of any cause, 16.8% optic neuritis, 40.8% cataract, and 25% retinopathies of multiple etiologies. Amblyopic patients presented less deterioration of the stereopsis (160 arc seconds), whereas patients with retinopathy presented more significant compromise (400 arc seconds). Patients with optic neuritis showed severe deterioration in contrast sensitivity; in the other pathologies, the decline was moderate. Nearly 42.4% of the patients with optic neuritis and 38% of the amblyopic patients did not present color vision disorders, whereas 32.6% and 31.2% of the patients with retinopathy and cataract showed tritanomaly.
Conclusion: Visual acuity is not equivalent to visual function. Stereopsis, contrast sensitivity, and color vision are affected by pathologies such as amblyopia, optic neuritis, cataract, and retinopathies. These assumptions of visual function could be considered for studies that take into account all the factors that may compromise the visual performance and, accordingly, define early diagnosis strategies, in addition to therapeutic behaviors such as performing early cataract surgery and visual rehabilitation.
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