31 results about "Spherical equivalent" patented technology

The invention discloses a subjective optometry instrument which comprises an imaging lens and a marker, wherein the front surface of the cornea of a testee is located at a focal point of the imaging lens, the marker and the eye of the testee are respectively located on the two sides of the imaging lens along the optical axis of the imaging lens, the marker can move forward and backward along the optical axis of the imaging lens after being set, the subjective optometry instrument marks a value D1 used for distinguishing the spherical equivalent along the moving path of the marker, a moving position x is obtained by subtracting the focal distance f0 from the object distance of the marker, and when the eye of the testee sees clearly the marker, the spherical equivalent of glasses to be worn on the eyes of the testee is the corresponding spherical equivalent D1 at the moving position x of the marker. The invention further discloses a subjective optometry method. Different from the traditional scheme, the positions of an eye lens and the human eye are needed to be moved to implement refraction compensation in the traditional scheme, the optometry method and the optometry instrument are not required to move the human eye and the lens, but only the marker is moved. When the optometry instrument and the optometry method are adopted in optometry, simplicity and convenience can be achieved, and the cost is low.

The present invention relates to a spectacle lens and a method for designing the spectacle lens. The invention provides spectacle lenses that allow the wearer to comfortably view a near object in binocular vision by using near regions of the spectacle lenses irrespective of the horizontal position of a target portion of the object. The spectacle lens is set that: compared with the spherical equivalent power at the near dioptric power measuring point on the main visual line in the near dioptric area of the spectacle lens, the spherical equivalent power at a point away from the near dioptric power measuring point NP horizontally toward the nose with reference to the spectacle wearer is set to decrease continuously, whereas the spherical equivalent power at a point away from the near dioptric power measuring point NP horizontally toward the ear is set to increase continuously.

A method for estimating and tracking refractive error progression of an individual includes estimating a percentile of Spherical Equivalent Refraction (SPHEQ) as a function of at least the individual's age by comparison to a reference population; estimating an expected SPHEQ trajectory over a future predetermined period of time; comparing the expected SPHEQ trajectory with the reference population; and comparing the expected SPHEQ trajectory with an expected SPHEQ trajectory using an ametropia control treatment, thereby showing a possible treatment benefit over the predetermined period of time.

An interactive fit tool and methodology which may be utilized by an eye care professional to improve the efficiency and final outcome in selecting a pair of contact lenses targeted towards a specific patient visual need in the treatment of presbyopia. The interactive fit tool comprises an application which includes images that would allow a patient to decide if he or she desires balanced visual acuity, near biased visual acuity, or distance biased visual acuity. In addition, the interactive fit tool comprises fit guide tables and performs the calculations for vertex distance and spherical equivalent.

The invention relates to a method for estimating spherical equivalent change degree before and after cycloplegia. The spherical equivalent change degree is estimated by measuring and adjusting an accuracy numerical value; in order to further improve the prediction accuracy, the eye axis length and the subject age can be increased to serve as reference factors, and a prediction result is obtained through a calculation model. The beneficial effects of the invention are that the method can achieve the effective estimation of the spherical equivalent change degree before and after cycloplegia; themethod is higher in predictability and can provide a new clinical standard for clinical ophthalmologists to evaluate whether children patients need to use a cycloplegia agent or not, so the diagnosisand treatment efficiency is improved, medical resources are saved, and related drug side effects borne by the patients due to unnecessary cycloplegia are reduced.

Properties of a porous solid sample 19, which may be a core of rock taken from below ground are carried out using apparatus which performs both nuclear magnetic resonance (NMR) and porosimetry measurements. The apparatus has a magnet 11,12 providing a magnetic field and a radio frequency coil 20 for transmitting and / or receiving electromagnetic radiation so as to bring about NMR in the magnetic field, a pressure vessel 14, 15 to hold a sample 19 within the magnetic field, a supply of a non-wetting liquid connected to the vessel, means to apply pressure to the non-wetting liquid to force liquid into pores of the sample 19 means to measure applied pressure of the non-wetting liquid and means to measure volume thereof taken up by the sample. The pressure of non-wetting liquid may be increased in steps, using intruded liquid volume at each step to give a measurement of pore throat size using NMR at each step to give a measure of pore size such as diameter of equivalent sphere. The non-wetting liquid may be mercury and NMR may observe the Knight shift of 99 Hg.

The invention discloses a method for converting equivalent grain size of a non-spherical bubble. The method comprises the following steps: calculating a coordinate of the center of mass for each bubble contour, establishing a plane right angle coordinate system with the center of mass as an origin of coordinates, separately calculating the numbers of pixels corresponding to radiuses in an X-axis direction and a Y-axis direction of the bubble contour and separately marking as rx, ry; separately selecting the rx and ry as the number of pixels rz corresponding to a radius in a Z-axis direction of a spatial right angle coordinate system of the bubble contour, calculating the volumes of two ellipsoids in accordance with an ellipsoid calculation formula, and solving a mean value of the volumes of the two ellipsoids as the volume of the non-spherical bubble; calculating the equivalent grain size of the non-spherical bubble by using a spherical volume formula. According to the invention, the method can implement 3D equivalent volume calculation of a 2D micro non-spherical bubble image, and can reduce errors in the course of equivalent conversion, increase precision of volume calculation, and further increase precision of equivalent spherical bubble grain size.

The invention discloses a method for measuring bubbles in a water body. The method comprises a bubble image identification process, a non-spherical bubble equivalent particle size conversion process and a bubble particle size inversion calculation process. By use of the bubble image identification process, bubble images and suspension images in the water body can be accurately distinguished from each other, and accurate bubble contours are obtained. By use of the non-spherical bubble equivalent particle size conversion process, errors in an equivalent conversion process can be reduced, and the calculation precision of equivalent spherical bubble particle sizes is improved. By use of the bubble particle size inversion calculation process, physical dimensions of bubble particle sizes are generated through combination of image calibration and inversion calculation. The precision is high, the real-time performance is good, original-position real-time measurement of physical parameters of the bubbles can be realized, and the method is suitable for wide application in such fields as scientific research, teaching, seawater monitoring and the like.

The invention relates to a preparation method of a nano-CaCO3-coated brucite composite material, which firmly and uniformly coats nano CaCO3 on the brucite particle surface by the following steps: carrying out wet-process ultrafine grinding to refine brucite particles used as the core, and carrying out depolymerization dispersion on the nano CaCO3 particles used as the coating until the brucite particles and nano CaCO3 particles are respectively refined to the matched particle size range, wherein the ratio of the brucite diameter (spherical equivalent diameter) to the CaCO3 particle diameter is about (8-10):1. The brucite particles subjected to ultrafine grinding generate the mechanical force surface activation effect, thereby promoting the interface combination between the brucite particles and nano CaCO3; and the brucite particles are subjected to ultrafine grinding and activation to form more structural hydroxy groups on the surface, the nano CaCO3 forms secondary hydroxy groups under the hydration actions of Ca<2+> and CO3<2->, and the reaction between the brucite particles and nano CaCO3 particles is implemented by chemical linkage among the surface hydroxy groups.