東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Astigmatism and eye growth: A study ...

Kee, Chea-su.

Linked to FindBook

Google Book

Amazon

博客來

Astigmatism and eye growth: A study on primates.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Astigmatism and eye growth: A study on primates./
Author:	Kee, Chea-su.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2003,
Description:	181 p.
Notes:	Source: Dissertations Abstracts International, Volume: 65-10, Section: B.
Contained By:	Dissertations Abstracts International65-10B.
Subject:	Ophthalmology. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3114657
ISBN:	9780496621460

Astigmatism and eye growth: A study on primates.
Kee, Chea-su.

Astigmatism and eye growth: A study on primates. - Ann Arbor : ProQuest Dissertations & Theses, 2003 - 181 p.

Source: Dissertations Abstracts International, Volume: 65-10, Section: B.

Thesis (Ph.D.)--University of Houston, 2003.

This item must not be sold to any third party vendors.

Purpose. Visual experience is important for normal eye growth especially during early infancy. Although astigmatism is prevalent in human infants, little is known about its etiology or its influence on early refractive development. This series of studies was undertaken to determine: (1) the prevalence of astigmatism in normal infant macaque monkeys; (2) if developing monkeys eyes are capable of growing in a way to eliminate optically imposed astigmatism; (3) the effects of optically imposed astigmatism on emmetropization; and (4) the astigmatism associated with experimentally induced spherical ametropias in macaque monkeys. Methods. The subjects were rhesus monkeys ( Macaca mulatta) that were reared with either unrestricted vision/zero-powered lenses (control group) or altered early visual experience (treatment group). Results. Experiment 1: Unlike human infants, infant monkeys showed a low prevalence of astigmatic errors. Experiment 2 : Although cylinder-lens-reared monkeys exhibited a high prevalence of ocular astigmatism, the axis of the induced astigmatism was not appropriate to compensate for the astigmatic error imposed by the treatment lenses. The astigmatism was corneal in nature, bilaterally mirror-symmetric and oblique in axis, and reversible. Experiment 3: Emmetropization in the cylinder-lens-reared monkeys appeared to be directed to one of the two principal meridians associated with the treatment lenses. The shifts in refractive error were mainly axial in nature. Experiment 4: In contrast to control monkeys, the experimental monkeys that had axial ametropias frequently developed significant amounts of astigmatism especially when their eyes exhibited relative hyperopic shifts in refractive error. The characteristics of the accompanying astigmatism were very similar to those found in cylinder-lens-reared monkeys. Conclusions. The low prevalence of astigmatism during early development suggests that astigmatism does not provide an essential cue for vision-dependent eye growth in normal infant primates. There was no evidence that macaque monkeys have an active, visually regulated "sphericalization" mechanism. However, in the presence of significant amounts of astigmatism, there was clear evidence that emmetropization was directed toward one of the two focal planes associated with the astigmatic principal meridians and not the circle of least confusion. The similarities between the astigmatic errors in our experimental monkeys and some astigmatic errors in humans suggest that vision-dependent changes in eye growth may contribute to astigmatism in humans. (Abstract shortened by UMI.).

ISBN: 9780496621460Subjects--Topical Terms:

862704
Ophthalmology.
Subjects--Index Terms:

Astigmatism

Astigmatism and eye growth: A study on primates.
LDR:03816nmm a2200361 4500 001 2279325
005 20210817105808.5
008 220723s2003 ||||||||||||||||| ||eng d
020 $a 9780496621460
035 $a (MiAaPQ)AAI3114657
035 $a AAI3114657
040 $a MiAaPQ $c MiAaPQ
100 1 $a Kee, Chea-su. $3 3557770
245 1 0 $a Astigmatism and eye growth: A study on primates.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2003
300 $a 181 p.
500 $a Source: Dissertations Abstracts International, Volume: 65-10, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Smith, Earl L., III.
502 $a Thesis (Ph.D.)--University of Houston, 2003.
506 $a This item must not be sold to any third party vendors.
506 $a This item must not be added to any third party search indexes.
520 $a Purpose. Visual experience is important for normal eye growth especially during early infancy. Although astigmatism is prevalent in human infants, little is known about its etiology or its influence on early refractive development. This series of studies was undertaken to determine: (1) the prevalence of astigmatism in normal infant macaque monkeys; (2) if developing monkeys eyes are capable of growing in a way to eliminate optically imposed astigmatism; (3) the effects of optically imposed astigmatism on emmetropization; and (4) the astigmatism associated with experimentally induced spherical ametropias in macaque monkeys. Methods. The subjects were rhesus monkeys ( Macaca mulatta) that were reared with either unrestricted vision/zero-powered lenses (control group) or altered early visual experience (treatment group). Results. Experiment 1: Unlike human infants, infant monkeys showed a low prevalence of astigmatic errors. Experiment 2 : Although cylinder-lens-reared monkeys exhibited a high prevalence of ocular astigmatism, the axis of the induced astigmatism was not appropriate to compensate for the astigmatic error imposed by the treatment lenses. The astigmatism was corneal in nature, bilaterally mirror-symmetric and oblique in axis, and reversible. Experiment 3: Emmetropization in the cylinder-lens-reared monkeys appeared to be directed to one of the two principal meridians associated with the treatment lenses. The shifts in refractive error were mainly axial in nature. Experiment 4: In contrast to control monkeys, the experimental monkeys that had axial ametropias frequently developed significant amounts of astigmatism especially when their eyes exhibited relative hyperopic shifts in refractive error. The characteristics of the accompanying astigmatism were very similar to those found in cylinder-lens-reared monkeys. Conclusions. The low prevalence of astigmatism during early development suggests that astigmatism does not provide an essential cue for vision-dependent eye growth in normal infant primates. There was no evidence that macaque monkeys have an active, visually regulated "sphericalization" mechanism. However, in the presence of significant amounts of astigmatism, there was clear evidence that emmetropization was directed toward one of the two focal planes associated with the astigmatic principal meridians and not the circle of least confusion. The similarities between the astigmatic errors in our experimental monkeys and some astigmatic errors in humans suggest that vision-dependent changes in eye growth may contribute to astigmatism in humans. (Abstract shortened by UMI.).
590 $a School code: 0087.
650 4 $a Ophthalmology. $3 862704
653 $a Astigmatism
653 $a Emmetropization
653 $a Eye
653 $a Primates
690 $a 0381
710 2 $a University of Houston. $3 1019266
773 0 $t Dissertations Abstracts International $g 65-10B.
790 $a 0087
791 $a Ph.D.
792 $a 2003
793 $a English
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3114657