Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Hyperopia”

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 1,783 records · Page 99Linked to original sources
PubMed1986

Critical evaluation of the NR-1000F Auto Refractometer.

The manifest (dry) refractions of 165 eyes of 86 patients, aged 6 to 75 years, were studied on the Nikon Auto Refractometer NR-1000F. The results obtained were compared with the clinical refractive data, and they were analysed for degree of agreement of various refractive components in different types and grades of refractive errors in the separate age groups. On the NR-1000F the spherical and cylindrical components and spherical equivalents skewed towards more minus (or less plus), especially so in emmetropes, low hypermetropes, and low myopes. This error declined with increasing age over 40 years and was also significantly lower in aphakia and mixed astigmatism. Determination of cylinder axis was found to be reliable on the NR-1000F. In spite of the obvious utility of the device its inbuilt automatic fogging system does not seem adequately to neutralise the patient's accommodative efforts, as the fixation target probably induces instrument myopia.

Adolescent↗
PubMed1987

An evaluation of the NR-1000F Auto Refractometer in high refractive errors.

The manifest refractions of 37 high myopic and 16 high hypermetropic eyes in a total of 28 patients, aged 5 to 42 years, were determined on the Nikon NR-1000F Auto Refractometer. The data obtained were compared with the final clinical prescriptions for these eyes and analysed for degree of agreement for the spherical equivalents, sphere components, and cylinder powers and axes. The Auto Refractometer recordings for all the different refractive components were observed to skew towards more minus in the high myopic eyes but more plus in the high hypermetropes. The possible significance of these skewing patterns is discussed with reference to our earlier studies.

Adolescent↗
PubMed1988

Changes in astigmatism between the ages of 1 and 4 years: a longitudinal study.

Changes in astigmatism during development were studied in 299 infants with astigmatism as they grew from 1 to 4 years of age. All consecutive cases of 1-year-old infants with an astigmatism of 1.0 D or more in at least one eye found at an ophthalmic screening survey were selected for follow-up. The cycloplegic refraction was longitudinally followed at yearly intervals. During development there was no decrease in the degree of hypermetropia, but there was a significant decrease in the incidence and amount of astigmatism during the test period. The most pronounced decrease in magnitude and incidence of astigmatism occurred between the first and second year of life. The majority of astigmatic eyes of the 1-year-old infants had a horizontal curvature greater than the vertical (plus cylinder axis of 180 degrees), and no changes of the axis of the astigmatism were noted during the following years.

Aging↗
PubMed1990

The association of Fuchs's corneal endothelial dystrophy with axial hypermetropia, shallow anterior chamber, and angle closure glaucoma.

A series of 24 patients with Fuchs's dystrophy are presented in whom detailed clinical measurement showed an association with axial hypermetropia and shallow anterior chamber. In 14 of these patients one cornea had developed oedema, of which 11 had required penetrating keratoplasty. Comparison of these eyes with the fellow eyes without corneal oedema revealed that the anomalies in measurement were not due to the process of decompensation. These 14 patients were then compared with the remaining 10 patients without corneal oedema in either eye, and a similar profile of anomalous measurements was observed. The whole group of 24 patients were then compared with three separate control groups, and in each case a significant trend towards hypermetropia, short axial length, and shallow anterior chamber was noted. The mean spherical equivalent refractive error in the patients with Fuchs's dystrophy was +2.48 D compared with -0.31 D for controls; corresponding means for axial length were 22.1 mm compared with 23.4 mm; and for anterior chamber depth were 2.2 mm compared with 2.7 mm. Each of these differences was statistically significant, but there was no significant difference for the keratometry measurements between patients and controls. Five of 24 (21%) of the patients had problems related to shallow anterior chambers of whom 3 (12%) had manifest angle closure glaucoma requiring surgical peripheral iridectomy. The aetiology of Fuchs's dystrophy and of ametropia is discussed and possible modes of association outlined. This previously unrecognised association gives a rational basis for the widely accepted practice of combining penetrating keratoplasty with lens extraction and has several other practical implications which are important in the differential diagnosis and treatment of Fuchs's dystrophy and angle closure glaucoma.

Adult↗
PubMed1990

Factors relating to visual acuity in children who have been treated for convergent squint.

Retrospective analysis of a selected sample of children who presented with convergent squint has shown that abnormal meridional hypermetropia (3.5 D or more) at age 1 was the principal factor associated with severe amblyopia (6/24 or less) remaining after conventional treatment. Neither the reported age of onset nor delay in presentation influenced the final visual outcome.

Amblyopia↗
PubMed1990

Results of a randomised trial of treating abnormal hypermetropia from the age of 6 months.

Children who were abnormally hypermetropic at the age of 6 months were randomly allocated treatment with spectacles or no treatment. The eventual incidence of squint was the same in both groups (approximately 24%). The last known visual acuity of the two groups was not significantly different either. Therefore there is no indication to screen infants with a view to preventing squint/amblyopia by optical correction of hypermetropia. If, however, the children allocated treatment are divided into two subgroups--those who wore glasses consistently and those who probably or certainly did not do so--the incidence of squint was the same, but the last known acuities of those who consistently wore glasses may be better than those who did not do so. This suggests that it may yet prove possible to prevent severe amblyopia.

Eyeglasses↗
PubMed1991

Emmetropisation, squint, and reduced visual acuity after treatment.

In a sample of children used to assess the value of optical correction of hypermetropia from the age of 6 months the refraction of the most hypermetropic meridian frequently became less than 3.5 D as the children grew. When this occurred, the incidence of squint was significantly less (p less than 0.001) and the last known acuity after treatment was significantly better (p less than 0.001) than when it did not. This process of emmetropisation appears to have been impeded by the consistent wearing of hypermetropic spectacle correction from the age of 6 months.

Eyeglasses↗
PubMed1992

Refraction changes in children developing convergent or divergent strabismus.

Strabismus and amblyopia were studied in a cohort of children born in 1979 or 1980 in the area of Västerås, Sweden. Forty percent of the children had participated in a voluntary eye examination at 1 year of age. All children diagnosed as strabismic and/or amblyopic between 1979 and 1988 at any of the three eye clinics in the area were included in this study. Strabismic cases were mostly detected by the parents while microstrabismus and straight eye amblyopia were found at the general 4 years of age screening at children's health centres. In 57 cases with (n = 31) and without amblyopia (n = 41) it was possible to obtain several refraction values between 1 and 6 years of age. In this study we concentrated on manifest esotropia and exotropia. The aim of the study was to describe changes of refraction before and after onset of strabismus and to establish risk indicators that identified populations at risk of developing strabismus. We found that patients with esotropia show a more pronounced hypermetropia than exotropic cases at the time of detection of strabismus. This difference becomes more definite over time, since hypermetropia increased in the deviating eye in the esotropic cases while refractive errors remained stationary in most of the exotropic eyes. It was also apparent that anisometropia frequently developed after onset of strabismus in esotropic cases in contrast to exotropic cases. An increasing refractive error in the deviating esotropic eye could be combined with an emmetropisation of the fixating eye.

Anisometropia↗
PubMed1995

Aland island eye disease: clinical and electrophysiological studies of a Welsh family.

Clinical and molecular genetic studies were performed on a single, large, white family, in which congenital nystagmus and moderate to high refractive error segregated as a sex linked trait with manifestation in some female carriers. In this family, affected males demonstrate myopia, but a high proportion of female carriers, and some of the possibly affected males, show hypermetropia. Clinical ophthalmic examination and electrodiagnostic studies of retinal function were fully compatible with a diagnosis of either incomplete congenital stationary night blindness or of Aland island eye disease. Previous studies have mapped both disorders to the proximal short arm of the X chromosome: our molecular studies support this localisation. Incomplete congenital stationary nightblindness and Aland Island eye disease could be considered as a single entity.

Adult↗
PubMed1998

Long-term effect of hypermetropic anisometropia on the visual acuity of treated amblyopic eyes.

AIM: To evaluate the effect of the extent of hypermetropic anisometropia on the long term visual acuity results in amblyopic eyes following their treatment by occlusion. METHODS: The visual acuity of 86 patients, who had been treated for unilateral amblyopia by occlusion of the fellow eye and followed up at least to the age of 9 years, was examined 6.4 years, on average, after cessation of treatment. Patients were divided into two groups--those with a small amount of hypermetropic anisometropia, where the spherical equivalent difference between the eyes ranged between 0 and +1.50 dioptres, and those with a large amount of hypermetropic anisometropia, where the difference was +1.75 dioptres or greater. RESULTS: Deterioration of visual acuity after cessation of occlusion treatment occurred in 51% of the patients in the group with a small amount of anisometropia and in 75% of the patients in the group with a large amount. At cessation of treatment, the average visual acuity in both groups was 20/40+. At the long term follow up examination, however, the average visual acuity was 20/40- and 20/70, respectively. This difference was statistically significant. CONCLUSIONS: Hypermetropic anisometropia greater than 1.50 dioptres appears to be a risk factor for deterioration of visual acuity in the long term, following treatment of amblyopic eyes by occlusion of the fellow eye.

Adolescent↗
PubMed1998

Ophthalmological long-term follow up of preterm infants: a population based, prospective study of the refraction and its development.

BACKGROUND: Numerous studies have reported an increased risk of refractive errors in prematurely born infants, but only few have been long-term and strictly population based. METHODS: A 3.5 year ophthalmological long term follow up of 248 preterm infants was performed. The infants had been included in a previous epidemiological study of retinopathy of prematurity (ROP) (birth weight < or = 1500 grams). The incidence of refractive errors and development of refraction were studied, based on retinoscopies at 6 and 30 months of corrected age. RESULTS: The overall incidence of myopia was 8% at 6 months, of which 35% was transient, and 10% at 30 months. Of the cryotreated infants, 30-40% were myopic at both retinoscopies. The incidence of astigmatism was 52% at 6 months and 26% at 30 months. Astigmatism was associated with ROP, but not with cryotreated ROP itself. Astigmatism "against the rule" was commoner than astigmatism "with the rule". Anisometropia occurred in 6.5% of the infants at 6 months and in 8.4% at 30 months. The incidence of anisometropia was higher in eyes with ROP, particularly in cryotreated eyes, which tended to have high and persistent anisometropia. CONCLUSION: The risk of refractive errors is higher in preterm infants than in infants born at term, and also prematurely born infants without ROP do run an increased risk of having myopia and anisometropia. We recommend follow up examinations with retinoscopy for all infants included in screening programmes for ROP.

Anisometropia↗
PubMed1999

Image quality in polypseudophakia for extremely short eyes.

AIM: To evaluate the image quality produced by polypseudophakia used for strongly hypermetropic and nanophthalmic eyes. METHODS: Primary aberration theory and ray tracing analysis were used to calculate the optimum lens shapes and power distribution between the two intraocular lenses for two example eyes: one a strongly hypermetropic eye, the other a nanophthalmic eye. Spherical aberration and oblique astigmatism were considered. Modulation transfer function (MTF) curves were computed using commercial optical design software (Sigma 2100, Kidger Optics Ltd) to assess axial image quality, and the sagittal and tangential image surfaces were computed to study image quality across the field. RESULTS: A significant improvement in the axial MTF was found for the eyes with double implants. However, results indicate that this may be realised as a better contrast sensitivity in the low to mid spatial frequency range rather than as a better Snellen acuity. The optimum lens shapes for minimum spherical aberration (best axial image quality) were approximately convex-plano for both lenses with the convex surface facing the cornea. Conversely, the optimum lens shapes for zero oblique astigmatism were strongly meniscus with the anterior surface concave. Correction of oblique astigmatism was only achieved with a loss in axial performance. CONCLUSIONS: Optimum estimated visual acuity exceeds 6/5 in both the hypermetropic and the nanophthalmic eyes studied (pupil size of 4 mm) with polypseudophakic correction. These results can be attained using convex-plano or biconvex lenses with the most convex surface facing the cornea. If the posterior surface of the posterior intraocular lens is convex, as is commonly used to help prevent migration of lens epithelial cells causing posterior capsular opacification (PCO), then it is still possible to achieve 6/4.5 in the hypermetropic eye and 6/5.3 in the nanophthalmic eye provided the anterior intraocular lens has an approximately convex-plano shape with the convex surface anterior. It was therefore concluded that consideration of optical image quality does not demand that additional intraocular lens shapes need to be manufactured for polypseudophakic correction of extremely short eyes and that implanting the posterior intraocular lens in the conventional orientation to help prevent PCO does not necessarily limit estimated visual acuity.

Astigmatism↗
PubMed2000

Effect of spectacles on changes of spherical hypermetropia in infants who did, and did not, have strabismus.

AIM: To explore why emmetropisation fails in children who have strabismus. METHODS: 289 hypermetropic infants were randomly allocated spectacles and followed. Changes in spherical hypermetropia were compared in those who had strabismus and those who did not. The effect of wearing glasses on these changes was assessed using t tests and regression analysis. RESULTS: Mean spherical hypermetropia decreased in both eyes of "normal" children (p<0.001). The consistent wearing of glasses impeded this process in both eyes (p<0.007). In the children with strabismus, there were no significant changes in either eye, irrespective of treatment (p>0. 05). CONCLUSIONS: In contrast with normal infants, neither eye of those who had strabismus emmetropised, irrespective of whether the incoming vision was clear or blurred. It is suggested that these eyes did not "recognise" the signal of blurred vision, and that they remained long sighted because they were destined to squint. Hence, the children did not squint because they were long sighted, and glasses did not prevent them squinting.

Eyeglasses↗
PubMed2001

Primary polypseudophakia for cataract surgery in hypermetropic eyes: refractive results and long term stability of the implants within the capsular bag.

AIM: To determine the long term visual and refractive results, and stability and complications of primary polypseudophakia using poly(methylmethacrylate) (PMMA) intraocular lenses (IOLs) for cataract surgery in hypermetropic eyes. METHODS: Prospective study of 15 short or hypermetropic eyes undergoing phacoemulsification with primary polypseudophakia with two PMMA IOLs implanted within the capsular bag. RESULTS: The spherical equivalent was reduced from a mean +4.87 (SD 3.00) dioptres (D) to -0.12 (1.40 D), and the deviation from the intended refraction was +0.005 (1.30) D, 23.6 (12.36) months post-implantation. The deviation from intended refraction was not statistically significant (p = 0.989; paired t test). Postoperative best corrected visual acuity (BCVA) was 6/12 or better in all eyes without macular or optic nerve co-morbidity. Interlenticular opacification (ILO) in the form of peripheral Elschnig pearls was seen in four (26.67%) eyes. A new type of ILO in the form of usually pigmented deposits in the central interface developed in five (33.33%) eyes and resulted in the appearance of Newton's rings in three. None of the eyes with ILO had any loss of BCVA or hyperopic shift. Six (40%) eyes were within 1 D from the intended refraction and 14 (93.33%) within 2 D. There was no statistically significant difference in the accuracy of the two intraocular lens calculation formulas used (SRK II and SRK/T). CONCLUSION: Peripheral Elschnig pearl-type ILO can occur as a late complication of primary in the bag implantation of two PMMA IOLs. A new type of ILO is described. Both types of ILO have not to date resulted in deterioration of visual acuity in our cohort. Use of appropriate biometry techniques and IOL calculation formulas may yield more accurate refractive results.

Aged↗
PubMed2001

Correction of refractive error in the Victorian population: the feasibility of "off the shelf" spectacles.

AIMS: To assess the feasibility of providing a stock of ready made spectacles for correction of refractive error in the general population. METHODS: Data were collected in the Visual Impairment Project, a population based survey of Victorian residents aged 40 years or older in randomly selected urban and rural sample areas. This included a refractive eye examination and the proportion of subjects with hypermetropia, emmetropia (defined as -1.0 to +1.0D spherical equivalent), and myopia documented in the 40-60 year age group. RESULTS: 2595 (54.8%) participants were aged between 40 and 60 years. Those with a best corrected visual acuity of less than 6/12, astigmatism of more than 1.25D, and anisometropia of more than 0.5D were excluded. 516 participants had refractive error which was deemed suitable for correction by "off the shelf" spectacles. This represents 19.9% of all participants between 40 and 60 years of age. Provision of spectacles in 0.5D increments would provide suitable stock spectacles for 85.5% of a -3.0 to +3.0D range or 89.2% of a -3.50 to +3.50D range. CONCLUSIONS: Ready made "off the shelf" spectacles could significantly alleviate visual morbidity due to refractive error in up to 20% of an urban population in Australia. This approach may also be useful in developing countries with poor access to optometric services.

Adult↗