(n.) A defect of the eye or of a lens, in consequence of which the rays derived from one point are not brought to a single focal point, thus causing imperfect images or indistinctness of vision.
Example Sentences:
(1) The authors have presented in two previous articles the graphic solutions resembling Tscherning ellipses, for spherical as well as for aspherical ophthalmic lenses free of astigmatism or power error.
(2) The high incidence of infant astigmatism has implications for critical periods in human visual development and for infant acuity.
(3) The most frequently occurring signs were: tilting of the disc (89%), oblique direction of the vessels (89%) and myopic astigmatism (96%).
(4) There was no evidence of glaucoma in any of the patients although two patients exhibited keratoconus and another one manifested moderate to high astigmatism.
(5) Of 809 eyes that underwent the Kelman phacoemulsification and aspiration (KPE) procedure, we report on 4 patients (0.49%) who developed sudden against-the-rule (AR) astigmatism after intraocular lens implantation.
(6) The two last methods are used for correction of astigmatism.
(7) The eyes were compared to 105 control eyes in which no astigmatic incisions were performed to assess the estimated effect of the TAK incisions.
(8) The choice of the method depends on the kind and degree of astigmatism and the degree of the spherical ametropia of the operated eye.
(9) The change in refractive astigmatism was as high as 1.50DC (diopter cylinder).
(10) The endpoint for the procedure is corneal astigmatism that will allow either spectacle or contact lens correction, depending on the patient's visual needs.
(11) A total of 527 astigmatic patients were examined for their axial distribution.
(12) Astigmatism greater than +1.25 diopters (as high as +5.50 diopters) was most commonly associated with dacryoceles (eight of 12 eyes) and with hemangiomas (14 of 17 eyes).
(13) In terms of the various keratometry values compared, mean K (corneal refractive power), flattest K, steepest K, astigmatism and the axis of astigmatism, 65% to 75% of the cases on automated keratometry were within 0.26 dioptres or 11 degrees of manually determined values; the difference was statistically significant (p < 0.001).
(14) Young adulthood myopia progression also appeared to be accompanied by a slight tendency toward a with-the-rule astigmatic shift.
(15) Forty-nine cases of primary keratophakia and 13 cases of secondary keratophakia were analyzed for postoperative astigmatism.
(16) A numerical example reveals some lesser known properties of the circle of least confusion of astigmatic pencils.
(17) Group II includes 10 patients with astigmatism due to circumscribed peripheral limbal corneal dystrophy.
(18) Amblyopia was due to anisometropia in 24 cases (50%), strabismus in 9 cases (18.7%), high astigmatism (meridional) in 7 cases (14.5%) and other causes or a combination of factors in 8 cases (16.7%).
(19) The differences between the 2 eyes were not statistically significant so far as the amount of astigmatism, final visual acuity, and peripheral anterior synechiae were concerned.
(20) Results showed that the wearing of spherical soft contact lenses, such as those used in this study, cannot be expected to predictably mask astigmatism.
Hyperopia
Definition:
(n.) Hypermetropia.
Example Sentences:
(1) Hyperopia was more common in younger persons, but senile cataract, macular degeneration and palpebral dermatochalasis or blepharochalasis were more common in older persons.
(2) Special education students had a higher incidence of uncorrected hyperopia and binocular dysfunction.
(3) We investigated a nonsurgical means of reshaping the cornea to correct hyperopia, keratoconus, or myopia.
(4) Relative hyperopia may persist, in spite of complete removal of the tumor.
(5) We conclude that the causes of the ESR elevation are more significant risk factors for CRVO, and systemic hypertension and hyperopia continue to be the main risk factors for BRVO.
(6) Ametropias showed a prevalence of 51.9%; the most common refractive defect was myopia followed by astigmatism and hyperopia.
(7) Complete optical constants and physical dimensions are presented for eight ametropic rhesus eyes in the range from -11.00 diopters of myopia to +8.00 diopters of hyperopia and compared with the same measurements from 40 essentially emmetropic normal control eyes.
(8) Significant differences between the younger and older normals existed for all types of refractive error except hyperopia in only one eye.
(9) The patient and his family had many congenital anomalies including hereditary brachydactyly, syndactyly, and hyperopia.
(10) 5 esotropias, 1 exotropia, 1 straight-eyed hypermetropic anisometropia of 4 diopters; 1 false positive high hyperopia (of +2.5 diopters) of both eyes.
(11) Usually soft lenses are well tolerated, so that patients suffering from aphakia as well as hyperopia should always use this type of lense.
(12) At the time of entry into the USAF, refractive error data were clustered around emmetropia with a definite skew toward hyperopia.
(13) Phakic eyes develop 5-7 diopters of hyperopia when the vitreous cavity is filled with silicone oil, and this puts them in the same range as the silicone oil filled aphakic eyes.
(14) This experiment showed that in every instance the cycloplegic estimate was equal to or greater in hyperopia or less in myopia than when performed without drugs.
(15) Contrary to previous reports, we do not find consistent high hyperopia in the rat, but rather refractions that range from near emmetropia (-0.12 D) to extreme hyperopia (+18.95 D).
(16) A new approach to surgical correction of hyperopia (including aphakia) is advanced.
(17) Although the latter is possible, the hyperopia may be coincidental and masking an underlying mechanism.
(18) We reduced the enlarged blind spot in a patient with focal peripapillary hyperopia, without papilledema, to near normal size by using progressively stronger plus lenses.
(19) Over 30% of the high hyperopes developed strabismus by age 3 years, but none of the infants in the moderate hyperopia or family history groups developed strabismus.
(20) The authors handled 75 such cases by first prescribing spectacles for full correction of hyperopia, and surgical operations were performed to the residual esotropia after wearing the spectacles for 6 months.