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At least 1,675 records · Page 93Linked to original sources
PubMed1979

Prevalence of monocular amblyopia among anisometropes.

Some 167 subjects showing anisometropia of at least 2 D, were selected from the records of the eye clinic of the Ramathibodi hospital in Bangkok, Thailand and 472 subjects showing anisometropia of at least 1 D were selected from the clinic records of the Indiana University, School of Optometry. The incidence of amblyopia (20/30 or less) was found to be 100% among least meridional hyperopic anisometropes of 3.5 D and greater, and among myopic anisometropes of 6.5 D and greater. Lower levels of anisometropia showed a smaller proportion of amblyopia. Comparable results were obtained for anisometropes computed in terms of mean spherical refractive error. Significant difference was not apparent for the Thai and American groups.

Adolescent↗
PubMed1981

Effect of ametropia on peripheral refraction.

Peripheral refraction was measured in 62 eyes along the horizontal meridian from 60 degrees nasally to 60 degrees temporally, using a Topcon refractometer. The amount of astigmatism was found to increase progressively, although less than predicted theoretically, toward the periphery in 91% of the eyes. Dividing the sample into myopes, hyperopes, and near-emmetropes showed that the type of astigmatism differed significantly with each group of eyes and that this factor played a most important role.

Adolescent↗
PubMed1981

Differences among myopes, emmetropes, and hyperopes.

One hundred fifty-two military recruits were classified as myopes, emmetropes, or hyperopes based on their measured farpoint. Height, weight, education, personality scores from the three scales of the Eysenck Personality Inventory, heart rate variability, autonomic nervous system indices, nearpoint, and dark focus were recorded for each subject. These were compared among groups using one-way analyses of variance and four discriminant analyses. Reliable differences were found among groups in each area referred to above: myopes weight less, completed more grades, had higher heart rate variability, and nearer nearpoints than hyperopes. Furthermore, myopes wee more consistent in their responses on the Eysenck Personality Inventory than emmetropes.

Adolescent↗
PubMed1981

Ocular component analysis by vergence contribution to the back vertex power of the anterior segment.

Refractive errors are essentially the expression of a dysfunction in a dynamic system of light vergences. It follows that the nature of the dysfunction can be studied by reference to the light vergences. However, the usual analysis deals with surface powers and their separations within the eye. These two dimensions do not express the actual functional conditions taking place within the optical system. Assessment of the optical elements and path lengths in terms of the actual vergence they produce does so. Hence, this paper presents a method using vergence to illustrate the value of such an assessment.

Adolescent↗
PubMed1982

The AC/A ratio and convergence in hypermetropia corrected with spectacles or contact lenses.

Some hypermetropes, when corrected with contact lenses, appear to have a much smaller AC/A ratio than when corrected with spectacle lenses. Ocular convergence measured with contact lenses is greater than that measured with spectacles. Studies were carried out to establish the cause of these effects. Theoretical considerations are compared with the experimental results obtained. This study emphasizes the importance of the different amounts of magnification induced by contact lenses as compared with spectacles.

Adolescent↗
PubMed1983

Ocular accommodation, personality, and autonomic balance.

The autonomic nervous system is made up of two subsystems: the parasympathetic (PNS) and the sympathetic (SNS). The balance between these systems regulates bodily functions during routine (PNS-dominant) and crisis (SNS-dominant) situations. It may also control visual accommodation: PNS activation for inward focus, and SNS activation for outward focus. Near- and far-sighted persons have been characterized as introverted and extraverted, respectively. These personality characteristics have been linked to autonomic balance: introversion and PNS-dominance, extraversion and SNS-dominance. Because autonomic balance may influence accommodation, the introversion of near-sighted and the extraversion of far-sighted persons may be related to the more general PNS-SNS balance rather than only to the difference in visual functioning. Research relevant to this hypothesis is reviewed.

Accommodation, Ocular↗
PubMed1984

Eyelid closure effects on the refractive error of the eye in dark- and in light-reared kittens.

Kittens reared in the dark with their eyelids sutured postnatally on one side have developed hypermetropia in the closed eye (average: +2.75 D for the horizontal meridian). This was significantly different (0.01 greater than p greater than 0.005) from the results of the open eye (+1.67 D; 180 degrees). The closed eye of light-reared kittens had similar refractive error (+0.33 D) to that of their open eye (+0.50 D), and to that of kittens light-reared with both eyes open (+0.75 D). Axial length of the closed eye in the dark-reared kittens and its corneal refractive power were smaller in comparison to the results for the open eye. It was concluded that in kittens lid closure during development in the dark induces hypermetropia.

Animals↗
PubMed1984

Visually related headache in a preschooler.

A female patient, age 4, presented with the chief complaint of severe headaches. Onset was within the past year. A neurological evaluation was conducted with negative results. Our testing revealed a moderate hyperopic refractive error, a marked lag of accommodation, and reduced stereopsis. The refractive error was corrected and a 6 week follow-up evaluation was performed. Correction of the refractive error resulted in abatement of the headache complaint, improved visual function, and improved preschool performance.

Accommodation, Ocular↗
PubMed1984

Static retinoscopy results with and without a fogging lens over the non-tested eye.

This study addressed the question: "Should both eyes be fogged during static retinoscopy?" Static retinoscopy measures were taken on young patients. (N = 50; mean age = 9 years, 4 months). Outcomes revealed no differences except with hyperopic patients, where the lack of a fogging lens over the partner eye resulted in a significant underestimate (p less than .001) of the refractive status. This argues against the use of a lens bar for retinoscopy especially in vision screening programs involving young children.

Adolescent↗
PubMed1985

An unusual case of antimetropia.

Antimetropia is a condition in which one eye is myopic and the fellow eye is hyperopic. This report describes functional and optical characteristics of a patient with a substantial degree of antimetropia.

Amblyopia↗
PubMed1985

Differences in the perceptual skills development of young myopes and hyperopes.

The purpose of this study was to compare the visual perceptual skills of young myopes and hyperopes. The case records of over 700 young University of Houston College of Optometry clinic patients revealed significant differences between the two groups (p less than 0.001), suggesting that myopes are, indeed, more analytical than hyperopes. Comparisons are also made with emmetropes. Implications of these data are discussed.

Age Factors↗
PubMed1986

Blink vergence in an antimetropic patient.

A patient with uncorrected antimetropia was found to attain motor fusion through blinking. Although this patient was also able to attain motor fusion through saccadic vergence and slow fusional vergence, he usually relied on blink vergence. In this patient, blink vergence was an efficient alternative to slow fusional vergence.

Adult↗
PubMed1987

Plus acceptance in hard contact lens wearers.

Hyperopes fitted with contact lenses often exhibit more plus acceptance compared to full spectacle correction beyond that accounted for by vertex distance considerations. The objective of this investigation was to attempt to identify the possible factors involved with this phenomenon. Eight hyperopes, one myope, and one control hyperope between 20 and 30 years of age were fitted with polymethyl methacrylate lenses, and over-refractions performed on different days with and without corneal anesthesia. The result was that every test hyperope accepted more plus without anesthetic than with anesthetic, by an average of 0.725 D, which was significant (p = 0.0000). One possible mechanism appears to be neurosensory feedback between corneal sensation and the level of accommodative tonus of the ciliary body.

Adult↗
PubMed1987

Tonic accommodation, accommodative hysteresis, and refractive error.

Accommodative hysteresis was compared in high myopes, low myopes, emmetropes, and hyperopes. Subjects consisted of 48 visually normal young adults who were fully corrected for their ametropia and equally distributed among the four refractive categories. Baseline measures of tonic accommodation, nearpoint, and farpoint were followed by a 10 min period of monocular fixation on a target which provided a stimulus equal to the subject's accommodative amplitude. The tonic measures were repeated immediately after fixation and were followed by either reassessment of the nearpoint and farpoint, or a 20 min period in darkness with reassessment of the tonic level at 5-min intervals. The period of sustained maximal focus produced significant increases in both tonic accommodation and the accommodative nearpoint in each refractive group. Although the magnitude of change was statistically equivalent across groups, a tendency to greater increases in tonic accommodation was noted for the high myopes. Although the farpoint remained relatively stable in the individual refractive groups, a slight inward shift was found in the combined sample. The tonic change diminished primarily during the first 5 min in darkness, with no significant difference in either the rate or degree of decay in the various refractive groups. The results indicate no clear association between susceptibility to accommodative hysteresis and refractive category.

Accommodation, Ocular↗
PubMed1989

Relation between clinically measured tonic accommodation and refractive status in 6- to 14-year-old children.

Previous studies have shown a relation between refractive status and tonic accommodation (TA), with corrected hyperopes displaying a significantly higher TA than corrected myopes. TA measurements in those studies were made on adult subjects, under laboratory conditions with an infrared or laser optometer. The study reported here used a different measurement method and younger subjects. The TA of 113 (19 hyperopic, 61 emmetropic, 33 myopic) children, ages 6 to 14 years, was measured by a clinical method described earlier. Analysis of variance indicated significant (p less than 0.25) between-group mean differences similar to the adult-subject data cited above. Clinical implications of the data and the measurement method are discussed.

Accommodation, Ocular↗
PubMed1989

Relation between tonic accommodation and visual perceptual skills development in 6- to 12-year-old children.

Refractive status has been shown to be related to both tonic accommodation (TA) and visual perceptual skills (VPS) development in children. The purpose of this study was to investigate possible direct links between TA and VPS development, independent of refractive status. The TA and VPS of 162 children (29 hyperopic, 81 emmetropic, 52 myopic) were assessed clinically. Analysis of the data corroborated the aforementioned relation between refractive status and TA, and between refractive status and VPS, but also revealed substantial within-refractive-group variability in TA and a highly significant relation between TA and VPS. The evidence indicates that children with high TA are much more likely to have delays in VPS development than are children with low TA, regardless of their refractive status.

Accommodation, Ocular↗
PubMed1990

Comparison of two clinical methods for measuring tonic accommodation in children.

Two methods have been described for measuring tonic accommodation (TA) under clinical conditions. One is the near retinoscopy (NEAR) method; the other uses Nott retinoscopy as the patient views a low spatial frequency difference of Gaussian (DOG) target. The purpose of this study was to compare the TA measures made by these two procedures on a group of 6- to 14-year-old children. The data indicate that the procedures yield significantly different information.

Accommodation, Ocular↗