Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “refractive error”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed1999

Intraocular lens tilt and decentration, anterior chamber depth, and refractive error after trans-scleral suture fixation surgery.

OBJECTIVES: To compare the extent of intraocular lens (IOL) tilt and decentration, as well as the anterior chamber depth after trans-scleral suture IOL fixation after either secondary out-of-the-bag or primary in-the-bag IOL implantation. DESIGN: Retrospective, comparative, nonrandomized, interventional study. PARTICIPANTS: Fifty-two eyes that underwent scleral suture fixation were compared with 51 eyes that underwent secondary out-of-the-bag implantation and 50 eyes that underwent in-the-bag implantation. INTERVENTION: One-piece polymethyl methacrylate IOL implantation by three different techniques. MAIN OUTCOME MEASURES: The tilt angle and decentration length of the IOL, as well as the anterior chamber depth, were measured by the Scheimpflug videophotography system. The spherical equivalent error from the predicted value was also examined. RESULTS: The mean tilt angle in the scleral suture fixation group was significantly greater than that in either the out-of-the-bag or the in-the-bag implantation group (P<0.0001). The mean decentration length was also largest in the suture group, followed by the out-of-the-bag group and the in-the-bag group (P<0.0001). The anterior chamber depth in the suture group and the out-of-the-bag group was significantly smaller than that in the in-the-bag group (P<0.0001). The spherical equivalent error in the suture group and the out-of-the-bag group was also greater than that in the in-the-bag group (P<0.0001). CONCLUSIONS: The extent of both tilt and decentration after scleral suture fixation was greater than that observed after either out-of-the-bag or in-the-bag implantation. The anterior chamber depth with the sutured or out-of-the-bag fixated IOL was shallower than that with the in-the-bag fixated IOL, which resulted in a significant myopic shift.

Adolescent↗
PubMed2002

Myopia and models and mechanisms of refractive error control.

Myopia represents a failure of the normal process of emmetropization, which is essentially endogenous to the eye. Emmetropization involves defocus detection at the level of the amacrine and bipolar cells of the outer retina, diffusion of a signal or signals across the retinal pigment epithelium and choroid, and alteration of the scleral matrix, likely through modulation of proteoglycan synthesis. Elucidating and effectively bolstering the deficient steps in this regulatory pathway would mark a significant advance given myopia's tremendous impact. Clinical experience, longitudinal studies, epidemiological data and numerous animal experiments have enhanced our understanding of myopia. Interpretation of the epidemiological data is often complicated by the difficulties of distinguishing environmental from genetic influences, especially those pertaining to slow developmental changes. Likewise, it is important that the animal models be interpreted with an appreciation that the human eye varies structurally and developmentally from that of other species. Studies of the chick eye have formed the basis for several hypotheses of myopic development, but the chick does not possess a fovea or retinal blood supply. It is unclear whether these differences alter the pathways of emmetropization. Even closely related primate species can exhibit different responses to form deprivation conditions, suggesting differing mechanisms of eye growth control. Monocular occlusion of the rhesus macaque, for instance, results in myopia when the ciliary muscle is paralyzed or the optic nerve cut, but does not in the stumptailed macaque, suggesting a role of excessive accommodation in the development of myopia in the stumptail but not the rhesus [36]. Given such variability in the models a persisting element of continued myopia research must be an evaluation of the relevance of any given model to the human condition. In this regard, the study of changing patterns of gene expression within and among species during emmetropization and myopic progression may offer a productive avenue for future research.

Disease Models, Animal↗
PubMed2005

Refractive errors in infancy predict reduced performance on the movement assessment battery for children at 3 1/2 and 5 1/2 years.

We have previously reported that significant hyperopia at 9 months predicts mild deficits on visuocognitive and visuomotor measures between 2 years and 5 years 6 months. Here we compare the motor skills of children who had been hyperopic in infancy (hyperopic group) with those who had been emmetropic (control group), using the Movement Assessment Battery for Children (Movement ABC). Children were tested at 3 years 6 months (hyperopic group: 47 males, 63 females, mean age 3 y 7 mo, SD 1.6 mo; control group: 61 males, 70 females, mean age 3 y 7 mo, SD 1.2 mo) and at 5 years 6 months (hyperopic group: 43 males, 56 females, mean age 5 y 4 mo, SD 1.7 mo; control group: 51 males, 62 females, mean age 5 y 3 mo, SD 1.6 mo). The hyperopic group performed significantly worse at both ages, overall and on at least one test from each category of motor skill (manual dexterity, balance, and ball skills). Distributions of scores showed that these differences were not due to poor performance by a minority but to a widespread mild deficit in the hyperopic group. This study also provides the first normative data on the Movement ABC for children below 4 years of age, and shows that it provides a useful measure of motor development at this young age.

Age Factors↗
PubMedDate not supplied

Astigmatic refractive errors associated with limbal dermoids.

A retrospective review of 17 patients with limbal dermoids revealed that 13 (76%) had astigmatism of 1.00 diopter or greater in the involved eye. In all but one patient, the minus cylinder axis of the astigmatism coincided with the location of the dermoid. Thirteen patients had surgery to remove the dermoids at ages ranging from 8 months to 15 years. The preoperative astigmatism persisted postoperatively with little change in its orientation or amount regardless of age at the time of surgery.

Adolescent↗
PubMed2005

Myopia: more than a refractive error--LASIK and retinal dystrophies.

Three patients who had undergone laser in situ keratomileusis (LASIK) correction for myopia were first seen because of suboptimal visual acuity (VA) and night blindness and/or photophobia. After a comprehensive examination including psychophysical and electrophysiological tests, two of the three patients were shown to suffer from a progressive conerod dystrophy. The third patient had retinitis pigmentosa. These cases illustrate the need for in depth preoperative evaluation in myopic patients about to undergo LASIK when signs or problems of night blindness and/or photophobia are present.

Adult↗
PubMed1991

Visual discomfort and astigmatic refractive errors in VDT use.

The purpose of this study was to evaluate the effects of small amounts of uncorrected astigmatism on the visual comfort of video display terminal (VDT) users. We hypothesized that these small errors produce visual discomfort in the use of these devices even though visual acuity is relatively unaffected. Eight subjects (ages 23-35 years) with corrected visual acuities of 20/20 participated. Our double-masked cross-over experiment included two 25-minute periods during which the subject read from a VDT. The subjects were randomly assigned to wear either the test lens pair (+0.50 D x 090) or a control lens pair (+0.12 DS) over their best correction during the first period and the alternative pair during the second period. A questionnaire was used to obtain ratings of visual discomfort. Our analysis of the data indicated greater reported eyestrain for the test lens pair (Wilcoxon signed-rank test, p = 0.01). These results suggest careful consideration be given to the correction of small amounts of astigmatic errors for VDT users.

Adult↗