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 865 records · Page 48Linked to original sources
PubMed1986

The effect of anticholinergic drugs on the inner eye muscles.

Using 12 healthy volunteers, we tested the para-sympatholytic effects on the eye. In a randomized crossover double-blind trial, hyoscine-N-butylbromide was tested against saline. Before (20 or 40 mg IV) and up to 45 min after the injection, pupillar light reaction, accommodation, visual acuity, and nyctometer values were measured. The range of accommodation diminishes according to dosage: 9-15 min after the injection, the inhibition is maximum; 45 min after the injection, only a small effect remains, even using the 40 mg dosage. Pupillary reaction is little affected by either dosage, and the pupil diameters at the end of the reaction are only slightly greater after the injection of either dosage than after placebo injection. The time constant of the reaction remains unchanged. Visual acuity and nyctometer values remain unchanged under the influence of hyoscine-N-butylbromide. The results are discussed with respect to the potential ability of a patient to meet the requirements of modern traffic. According to our findings, there are no ophthalmologically-based reasons for an emmetropic person to assume impaired driving abilities after a single injection of hyoscine-N-butylbromide of up to 40 mg. If the accommodative capacity of a patient is impaired whose hyperopia is not fully corrected, the ability to drive in modern traffic may be impaired. After a single dose of 20 mg hyoscine-N-butylbromide (i.e., 1 ampule Buscopan), the impairment of even these patients does not last longer than about 45 min.

Accommodation, Ocular↗
PubMed2003

[Examination of preschool children for refractive errors. First experience using a handheld autorefractor].

BACKGROUND: Since ametropia is a leading cause of amblyopia refractive screening of preschool children is recommended. Measurement of refraction using tabletop autorefractors can be difficult or impossible due to lack of cooperation in this age group. The intention of the present study is to evaluate the use of a new handheld autorefractor for screening in kindergartens. METHODS: A total of 216 children aged 3.5-4.5 years were examined without cycloplegia using the handheld autorefractor (SureSight, Welch Allyn) in their kindergartens. RESULTS: Using the test device the majority of the examined eyes showed mild hyperopia (on average +1.18+/-0.87 dpt spherical equivalent) and mild astigmatism (on average 0.60+/-0.46 dpt cylinder power). The reproducibility of repeated autorefractor readings was higher for cylinder power and axis than for the spherical equivalent. Autorefractor readings of 55 eyes could be compared with the results of cycloplegic retinoscopy. The results were similar between the two measurements with differences of no more than 0.5 dpt in 18.2% for the spherical equivalent, in 82.1% for cylinder power, and in 66.6% for axis (weighted axis difference). There was adequate cooperation in 99.5% of the children. CONCLUSION: The handheld autorefractor proved an accuracy of measurement comparable to that of conventional tabletop autorefractors for cylinder power and axis with limitations in accuracy for the spherical equivalent. Validity and threshold values for relevant abnormalities are to be evaluated in further studies. By the high cooperation rate the instrument proved useful for screening examinations in preschool children.

Child, Preschool↗
PubMed2005

[Microbial keratitis following laser in situ keratomileusis. Prevention, differential diagnosis, and therapy].

Laser in situ keratomileusis (LASIK) is an effective option and currently one of the most commonly applied surgical techniques in the correction of refractive errors such as myopia, hyperopia, and astigmatism. In contrast to photorefractive keratectomy, it maintains the integrity of Bowman's membrane and the epithelium leading to faster visual rehabilitation as well as less pain and discomfort. Nevertheless, following LASIK the stroma is exposed to infectious organisms. Sight-threatening complications after LASIK are reported to be as rare as 1 in 1000 procedures. However, any infectious keratitis remains potentially devastating. Reports about infectious keratitis following LASIK have increasingly surfaced in recent years. We present a review of the literature on microbial keratitis and present our own cases and recommendations for possible prophylaxis and therapy.

Adult↗
PubMed2006

[Optical quality after refractive corneal surgery].

Correction of myopia, hyperopia and astigmatism within its indicated margin by means of refractive corneal surgical procedures such as LASIK and surface ablation (e.g. PRK) is one of the standard procedures in ophthalmology. Now that advances in the fields of surgical techniques and the technical devices employed have further progressed in terms of safety and predictability, research also focuses on optical quality. "Optical quality" is not a clearly defined parameter, but can be captured indirectly by means of directly measured data. One has to start with the anatomical properties of the eye, which determine the optical images on the retinal level. The quality of the retinal image influences the eye's function, i.e. acuity and contrast perception. Finally, there is the subjective perception of the image we receive. "Optical quality" as such is reflected by the patient's evaluation of this image perception. Three phenomena are especially responsible for deterioration of the quality of the retinal image: diffraction, aberrations and dispersion. Some of the methods for measuring optical quality are subjective questionnaires, functional testing procedures for measuring visual acuity and contrast sensitivity, optical measuring procedures for the determination of optical quality, as well as biomicroscopy, aberrometry and corneal topography for assessing anatomical changes.

Cornea↗
PubMed2006

[PresbyLASIK: treatment approaches with the excimer laser].

Presbyopia represents the most common refractive error. There is currently no surgical treatment for presbyopia, which is effective, reliable, and safe. Excimer laser surgery has become a routine procedure for the correction of myopia, hyperopia, and astigmatism for years. Various treatment strategies for presbyopia have been brought forward using the excimer lasers. Besides monovision, creation of a multifocal cornea represents an attractive option. This procedure is also called "PresbyLASIK." Different ablation profiles to form a multifocal cornea are reviewed here and first clinical results are summarized."PresbyLASIK" is a new, interesting treatment strategy, with a huge potential for the future. At the present it should be used in controlled studies only because of some unsolved questions.

Humans↗
PubMed1999

[Early and late occurring consecutive exotropia following a medial rectus faden operation].

UNLABELLED: The main advantage of the bilateral medial rectus faden operation (posterior fixation suture) for the treatment of essential infantile esotropia is the low occurrence of delayed consecutive exotropia. Nevertheless, this unwanted complication also occasionally occurs after a faden operation. PATIENTS: All patients operated on between 1988 and 1997 for subsequent exotropia following bimedial faden operations without recessions were included in this study. Surgery for exotropia consisted of uni- or bilateral lateral rectus muscle recession or in removing the faden with or without resection. RESULTS: Within the 10 years examined a bimedial faden operation (without recession) was performed in 1569 patients. In the same period 49 patients were operated on for a consecutive exotropia after a faden operation. Thirty-four (69.4%) of the consecutive exotrope patients showed exodeviation immediately following the surgery (group I). Fifteen (30.6%) patients developed manifest exotropia 1-53 months later (group II). The hyperopia at the time of the first operation was 2.5 D in group I and 2.3 D in group II (spherical equivalent). A bimedial faden operation with simultaneous shortening of the anterior muscle segment was performed in four patients in group II and only in two patients in group I. Cerebral palsy was evident in three patients in group II and also so in three patients in group I. CONCLUSION: Exotropia appearing immediately after surgery is most likely the result of an individually overdosed operation. This conclusion is not sufficient for delayed exotropia. Motor and sensory instabilities, such as those in patients needing a faden operation with simultaneous shortening of the anterior muscle segment for the treatment of convergence excess with no deviation at far or in patients showing cerebral palsy, seem to increase the risk of delayed consecutive exotropia. The mean interval between the initial surgery and the manifestation of consecutive exotropia is lower than is known from other surgical procedures.

Adolescent↗
PubMed2002

[Striae in the flap after laser in situ keratomileusis. Etiology, diagnosis and treatment].

OBJECTIVE: Laser in situ keratomileusis (LASIK) has become the leading refractive option to correct myopia, hyperopia and astigmatism. In addition to the relative rapid visual recovery and the lack of postoperative pain, new flap-related complications are being added. The formation of striae can lead to a significant loss of corrected visual acuity if the central pupil zone is affected. Awareness of possible complications is important not only for the surgeon, but also for the ophthalmologist in practice for a rapid diagnosis and prompt management. CLINICAL COURSE AND THERAPY: Striae have a variety of appearances and are caused by misalignment/displacement of the corneal flap after replacement or are results of a slippage effect of the flap over the stromal bed after LASIK. Symptomatic striae ideally are treated on the first or second day after surgery by refloating the flap, irrigation with balanced salt solution or hypotonic saline solution, stroking and stretching the surface with moist and dry sponges. In more severe cases scraping away the epithelium and antitorque or interrupted sutures can be performed to treat persistent striae. CONCLUSION: Symptomatic deep striae should be diagnosed early and managed promptly within the first days. Any later intervention decreases the chance of successful elimination and visual outcome. Hints to prevent the development of striae formation are provided.

Corneal Diseases↗
PubMed2002

[Ocular involvement in nail-patella syndrome (#161200)].

PURPOSE: The "nail-patella syndrome" (NPS) is an autosomal dominant hereditary systemic disease. The underlying defect of the LMX1B gene is localised on chromosome 9q34 and causes various typical clinical signs such as onychodysplasia, patella hypoplasia, renal involvement and open angle glaucoma. PATIENTS: A 42-year-old mother and her 4-year-old son were examined in our hospital in order to exclude ocular involvement in a genetically confirmed "nail-patella syndrome". A clinical examination including corneal topography, gonioscopy as well as measurement of intraocular pressure and bulbus length was performed. RESULTS: The examination of both patients showed NPS-specific symptoms, however the boy revealed no indications of glaucoma. He suffered from marked amblyopia caused by excessive astigmatism of the left eye and a bilateral moderate hyperopia. CONCLUSION: Because of the co-segregation between the syndrome and open angle glaucoma, NPS patients should undergo regular ophthalmological controls including measurement of intraocular pressure. Experiments on mice have shown that mutations of the LMX1B gene result in alterations of several structures of the anterior segments. Thus, the described refraction abnormality could be the consequence of structural changes at the corneal level due to NPS.

Adult↗
PubMed2001

[Differentiation between dyslexia and ocular causes of reading disorders].

BACKGROUND: Dyslexia is defined as a reading and/or writing disability persisting after exclusion of organic causes. Studies show that ocular disorders, especially small refraction errors, hypoaccommodation and symptomatic heterophoria, are often not detected or treated in cases of reading and/or writing problems which were otherwise diagnosed as dyslexia. METHODS: We evaluated the data of patients referred to our department from December 1997 to March 2000 with the diagnosis of dyslexia. RESULTS: We found ocular disturbances in 28 (84.8%) out of 33 children, 26 (78.8%) showed improved reading after therapy. They had mostly accommodative problems: uncorrected hyperopia, hypoaccommodation and/or exophoria compensated by accommodative convergence (pathophoria). CONCLUSIONS: Our results underline the importance of the correction of even small refraction and/or motility errors in the presence of reading and writing difficulties.

Accommodation, Ocular↗
PubMed1979

Follow-up of intrauterine transfused surviving children.

The long-term effects of intrauterine transfusion (IUT) are still being assessed since the procedure was first reported in 1963. Therefore, we undertook a follow-up study on the survivors of 57 infants who received IUT's between 1966 and 1975. Forty-two infants were born alive, but 15 died in the neonatal period. Overall survival was 27/57 (48%). An extensive follow-up examination was carried out at age 22 months to 10 years in 21/27 survivors. Height was below the third percentile in one child and head circumference above the mean and 2 SD in another. Of 21 children, 19 had normal vision, one was slightly myopic, and one had hyperopia. One child had unilateral high-frequency hearing loss. All had normal EEG's and none have mental retardation but 2/21 have "major" and 6/21 have "minor" neurologic signs. No evidence of passive antibody transfer was found, but minor disturbances of immunoglobulin levels were present.

Blood Cell Count↗
PubMed1976

Dominantly inherited cystoid macular edema.

An apparently autosomal-dominant macular dystrophy occurred in three pedigrees with the presenting signs of typical cystoid macular edema due to leaking perimacular capillaries. Other striking features were retinal capillary leakage all over the posterior pole of the eye, whitish punctate deposits in the vitreous body, a normal electroretinogram, a subnormal electro-oculogram, and moderate to high hyperopia. In later or more advanced stages the macula developed a central zone of "beaten bronze" atrophy. Strabismus occurred frequently.

Adolescent↗
PubMed1977

Dominant cystoid macular dystrophy.

Of 24 examined family members, 14 had an undescribed macular dystrophy. There is a clear autosomal-dominant heredity. Essential features of the disease are pigmentary disturbance, cystoid macular edema, wrinkling of the internal limiting membrane, and vitreous body changes. In this family there was an increased incidence of severe hyperopia (greater than or equal to 6 diopters). As the disease progressed color vision deteriorated (type 1 acquired red-green defect), disturbance of the electro-oculogram became more prevalent, and the electroretinogram was normal. These finding differentiate this dystrophy from other diseases with a bull's eye aspect or cystoid macular edema and from vitreoretinal syndromes.

Aged↗
PubMed1979

Congenital retino-pigment epithelial malformation, previously described as hamartoma.

Six patients with a congenital malformation of the retina and pigment epithelium had a slightly elevated greenish-blue or gray lesion in the macular area or fundus periphery composed of a flat, outer pigmented portion consisting of a layer of hyperpigmented, presumably hypertrophied retinal pigment epithelium and a prominent, unpigmented inner portion consisting of malformed thickened retina. Marked tortuosity of the retinal vessels was explained by an intraretinal disturbance of the retinal layering and the presence of preretinal membranes. Angiography revealed blockage of the background fluorescence caused by the abnormal retinal pigment epithelium and leakage from dilated, abnormal capillaries. Typically, the lesion was unilateral and was found in children or young adults who had monocular strabismus, reduced visual acuity, and often hyperopia. Most of the patients were males, and their cases were frequently misdiagnosed as tumors.

Adolescent↗
PubMed1983

Relationship between arterial pulsations and intraocular pressure.

A model of the eye is proposed in order to find a relationship between small changes in volume and the intraocular pressure in terms of the physical parameters of the globe. The results show that pulsations in pressure due to small variations in volume are directly proportional to the average intraocular pressure and inversely proportional to the radius of the globe. Comparisons are made between the results of this model and already existing experimental and clinical measurements. Further clinical and experimental studies are suggested to confirm the accuracy of the model. Conclusions are drawn connecting the findings to open angle glaucoma and to the effects of axial myopia and axial hyperopia.

Biometry↗
PubMed1983

Longitudinal chromatic aberration of the vertebrate eye.

A recent study involving Abbe and Pulfrich refractometry analyses the dispersion of the human lens and the ocular media of a number of vertebrates. In general, the lens and, to a lesser extent, the cornea, are more dispersive than expected at wavelengths below 500 nm. The dispersion findings of this study were used in conjunction with reduced eye parameters of a number of vertebrates to calculate the longitudinal chromatic aberration of rock bass, frog, chicken, rat, cat, pig, cow, and human eyes. The calculated chromatic aberration of the human eye is greater than values reported earlier, because of the exaggerated dispersion of the lens at short wavelengths. While the values calculated for the additional species studies may be larger in some instances than expected, presumably due to lens dispersion as well, chromatic aberration is not large enough to account for the hyperopia found by retinoscopic study of small eyes.

Animals↗
PubMed1991

The regulation of eye growth and refractive state: an experimental study of emmetropization.

During growth the vertebrate eye achieves a close match between the power of its optics and its axial length with the result that images are focused on the retina without accommodative effort (emmetropia). The possibility that vision is required for the regulation of eye growth was studied experimentally in chicks made myopic or hyperopic by different visual manipulations. After discontinuing these visual manipulations, the eyes returned quickly to emmetropia mainly by adjusting the growth of their vitreous chambers; growth stopped in eyes recovering from myopia and continued in eyes recovering from hyperopia. Because both hyperopic and myopic eyes were already larger than normal controls, the difference in growth indicates that refractive error, rather than eye size per se, guides the eye toward emmetropia. Evidence is also presented for nonvisual shape-related control of eye growth, but this is slow-acting and cannot explain the emmetropization from induced refractive errors. Both the visually guided and shape-related mechanisms work even in eyes with the optic nerve cut, indicating that the two mechanisms are local to the eye. Although the optic-nerve-sectioned eye can sense the sign of a refractive error and initially adjust growth accordingly, it eventually overshoots emmetropia and reverses the sign of the initial refractive error. Whether this is due to loss of feedback from the central nervous system or retinal ganglion cells is unclear.

Aging↗
PubMed1992

Normal development of refractive state and ocular component dimensions in the tree shrew (Tupaia belangeri).

The normal development of refractive state, ocular components and simple visually-guided behaviors was examined in maternally-reared tree shrews. Six groups consisting of 5 animals each were anesthetized and examined after 0, 15, 30, 45, 60 and 75 days of normal binocular visual exposure. Measures in the 75-day group provided values for an improved schematic eye of the tree shrew. Cycloplegic refraction showed a marked hyperopia (+25 D) at eye opening which decreased rapidly during the first 15 days of visual exposure and stabilized near the value (+5 D) expected in an eye of this axial length (approx. 7.8 mm). Corneal radius increased slightly during development. Anterior segment depth, measured by A-scan ultrasonography, seemed to complete most of its development at an earlier age (15-30 days of visual exposure) than did other ocular parameters. Lens thickness increased steadily throughout development. Vitreous chamber depth increased rapidly until 15 days of visual exposure, and then decreased because the lens thickness increased more rapidly than axial length. Crude orienting to, and following of, large objects developed shortly after eye opening (median age at onset, 5 and 6 days, respectively). Triggered visual placing responses developed at about the same time that the refractive state completed the rapid drop from highly hyperopic values. The slowed rate of ocular development after 15 days of visual exposure may be related to increased retinal activity that is permitted by neural maturation and by the presence of a relatively well-focussed retinal image. The increased activity may influence the final dimensions of the eye to coordinate the axial length with the focal length of the eye.

Animals↗
PubMed1993

Ocular development and visual deprivation myopia in the common marmoset (Callithrix jacchus).

The normal postnatal ocular development of the common marmoset (Callithrix jacchus) and the effects of visual deprivation on eye growth and refractive state are described. The marmoset normally undergoes a developmental process of emmetropization from high hyperopia at birth. This emmetropization is easily disrupted by visual deprivation produced by lid-suture. Myopia and axial elongation of the vitreous chamber are induced by visual deprivations of 12, 5, and 3 weeks duration. The development of axial myopia after 3 weeks of visual deprivation differs from longer duration deprivations in that the experimental eyes are initially shorter than normal and hyperopic at the end of the visual deprivation period, but subsequently become longer than normal and myopic. Visual deprivation myopia in the marmoset persists even after the deprivation is discontinued and a visual signal is restored. In all experimental groups, the development of the eye in response to the cessation of visual deprivation shows no slowing of vitreous chamber enlargement; the axial enlargement relative to the control eye is either maintained or increases and produces significantly greater myopia. These results suggest that the visual control of postnatal eye growth in the marmoset may be unidirectional in its response to visual experience and able only to increase the growth rate of the vitreous chamber, possibly after an initial delay.

Animals↗