On the calculation of power from curvature of the cornea.
نویسنده
چکیده
The theoretical basis for the calculation of corneal refractive power from anterior curvature is considered. It is shown that the power can be calculated with sufficient accuracy from one simple formula provided the refractive index of the 'cornea' is 1.3315. It is suggested that keratometer readings should be calibrated with this value in order to increase the accuracy in intraocular lens calculation.
منابع مشابه
Use of the Posterior/Anterior Corneal Curvature Radii Ratio to Improve the Accuracy of Intraocular Lens Power Calculation: Eom's Adjustment Method.
Purpose To evaluate the accuracy of IOL power calculation using adjusted corneal power according to the posterior/anterior corneal curvature radii ratio. Methods Nine hundred twenty-eight eyes from 928 reference subjects and 158 eyes from 158 cataract patients who underwent phacoemulsification surgery were enrolled. Adjusted corneal power of cataract patients was calculated using the fictitio...
متن کاملبررسی اثر قطره هوماتروپین 2% بر روی توپوگرافی قرنیه
ABSTRACT The purpose of this study was the evaluation of cycloplegic effect of homatropine 2% on central corneal curvature and power. 43 volunteers who participated in the study were examined. Thirty-nine of them (28 men and 11 women) which had normal eyes with visual acuity of 20/20 and a mean age of 29.6 ± 6.7 years were selected. Then corneal topography was performed on both eyes. After per...
متن کاملThe Research on the Biggest Borehole Curvature that Allowed through for the Rotating Casing (RESEARCH NOTE)
With the development of highly-deviated well cementing techniques, rotating casing cementing technology has got more and more attention. The rotating casing technique can improve the displacement efficiency of cement paste, and then enhance the quality of well cementation. In the stuck section, the rotating casing can redress the well to make the casing run sequentially. The casing endures shea...
متن کاملBack-calculation of mechanical parameters of shell and balls materials from discrete element method simulations
Discrete Element Method (DEM) is extensively used for mathematical modeling and simulating the behavior of discrete discs and discrete spheres in two and three dimensional space, respectively. Prediction of particles flow regime, power draw and kinetic energy for a laboratory or an industrial mill is possible by DEM simulation. In this article, a new approach was used to assess the main paramet...
متن کاملMagneto-electro-mechanical size-dependent vibration analysis of three-layered nanobeam with initial curvature considering thickness stretching
Thickness stretching effect based on shear and normal deformation theory is used in this paper for magneto-electro-elastic vibration analysis of a three-layered curved nanobeam including a nano core and two piezo-magnetic layers. Size-dependency is included in derivation of governing equations of motion based Eringen's nonlocal elasticity theory. The initial curvature is accounted in calculatio...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The British journal of ophthalmology
دوره 70 2 شماره
صفحات -
تاریخ انتشار 1986