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Prentice's rule, named so after the optician Charles F. Prentice, is a formula used to determine the amount of induced prism in a lens: = where: P is the amount of prism correction (in prism dioptres) c is decentration (the distance between the pupil centre and the lens's optical centre, in millimetres)
Esophoria is an eye condition involving inward deviation of the eye, usually due to extra-ocular muscle imbalance. It is a type of heterophoria. Cause. Causes include: Refractive errors; Divergence insufficiency; Convergence excess; this can be due to nerve, muscle, congenital or mechanical anomalies.
Convergence Insufficiency. Other names. Convergence disorder. Specialty. Ophthalmology, optometry. Convergence insufficiency is a sensory and neuromuscular anomaly of the binocular vision system, characterized by a reduced ability of the eyes to turn towards each other, or sustain convergence .
Efforts must first be made to identify and treat the underlying cause of the problem. Treatment options include eye exercises, wearing an eye patch on alternative eyes, prism correction, and in more extreme situations, surgery or botulinum toxin.
The majority of esotropias are concomitant and begin early in childhood, typically between the ages of 2 and 4 years. Incomitant esotropias occur both in childhood and adulthood as a result of neurological, mechanical or myogenic problems affecting the muscles controlling eye movements.
Watterson estimator. In population genetics, the Watterson estimator is a method for describing the genetic diversity in a population. It was developed by Margaret Wu and G. A. Watterson in the 1970s. [1] [2] It is estimated by counting the number of polymorphic sites.
The second eye, with a −4.00 diopter prescription, is the weaker eye, needing moderate correction to sharpen the image formed, and hence a moderately thick spectacle lens—if the aniseikonia is ignored.
The models described on this page describe the evolution of a single site within a set of sequences. They are often used for analyzing the evolution of an entire locus by making the simplifying assumption that different sites evolve independently and are identically distributed.
Importantly, the formula can be re-written as a linear equation in terms of f: P = ( 5 10 q − 5 90 ( 1 − q ) ) f + 5 90 ( 1 − q ) . {\displaystyle P=\left({\frac {5}{10}}q-{\frac {5}{90}}(1-q)\right)f+{\frac {5}{90}}(1-q).}
CKD-EPI formula. The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) formula was published in May 2009. It was developed in an effort to create a formula more accurate than the MDRD formula, especially when actual GFR is greater than 60 mL/min per 1.73 m 2. This is the formula currently recommended by NICE in the UK.