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At least 1,207 records · Page 67Linked to original sources
PubMed1989

The current and future status of refractive surgery.

Kerato-refractive surgery has developed rapidly over the past decade. Many surgical procedures have been described for the correction of myopia, hyperopia, and aphakia. For the treatment of myopia, radial keratotomy has been utilized extensively. Most investigators agree that radial keratotomy results seem to be better in patients with 3 diopters or less of myopia. Keratomileusis is a complicated procedure which can correct high degrees of myopia, however, this technically difficult procedure is performed by very few surgeons in North America. Epikeratophakia for the treatment of aphakia is promising especially in the treatment of pediatric patients. The Excimer laser is evolving from a research tool to clinical reality with the coupling of the laser to computer controlled programs to reshape the cornea. The use of synthetic material inlays and intrastromal corneal ring implants are also being developed to modify the refractive status of the cornea.

Aphakia↗
PubMed1988

Refractive error and preferential looking visual acuity in infants 12-24 months of age: year 2 of a longitudinal study.

This paper presents data from year 2 of a study assessing changes in visual acuity and refractive error in normal, healthy infants between birth and 24 months of age. Visual acuity and refractive error measurements were taken at 2-month intervals on 18 infants, 12-24 months of age. The acuity card preferential looking procedure and Mohindra's near retinoscopy were used for acuity and refractive error measurement. Response to the Stereo Fly was also observed. Mean acuity improved from 6.4 cycles per degree (cpd) (20/93) at 12 months to 20.5 cpd (20/29) at 24 months (SD = 0.5 octave). Refractive error remained in low hyperopia (X = 0.4D, SD = 0.5D). Amount and frequency of astigmatism showed little change. Response to the Stereo Fly improved from 0% at 12 months to 87% at 24 months. The acuity card procedure was easily accomplished, but more difficult with these children at 12-24 months of age than when previously tested between 0-12 months of age.

Analysis of Variance↗
PubMed1988

Vision anomalies and reading skill: a meta-analysis of the literature.

We report a meta-analysis of studies of the relation of vision anomalies to reading skill. Meta-analysis is a quantitative technique for combining the results of multiple studies that reduces the subjectivity of literature reviews. The results of the analysis of 34 studies of vision anomalies and reading skill that met the criteria for inclusion in the meta-analysis showed that hyperopia, exophoria at near, vertical phoria, anisometropia, and aniseikonia are associated with below average reading performance. Myopia and esophoria and esophoria at far are associated with average and above average reading performance. Reduced visual acuity, astigmatism, esophoria at near, fusional convergence and divergence, strabismus, nearpoint of convergence, and stereopsis were not found to be associated with reading performance.

Depth Perception↗
PubMed1987

Different visual deprivations produce different ametropias and different eye shapes.

To compare the effects on the postnatal development of the eye of both total and partial form deprivation in diurnally reared chicks and of dark-rearing, chicks were reared with occluders covering one eye from hatching for up to 6 weeks. In diurnally reared birds, both total and partial form deprivation resulted in severe axial myopia and increased eye size. These effects were greatest for the eyes of chicks raised with total form deprivation; they had highly curved corneas and very deep anterior and vitreous chambers. In addition, the amount of myopia produced in eyes with total form deprivation was the same at 2 and 6 weeks, whereas eyes with partial form deprivation showed substantial remission even with the occluders left on. The partially deprived eyes developed a striking shape asymmetry: the posterior globe only became enlarged in the deprived region of the retina. The eyes of dark-reared chicks, regardless of whether or not an occluder was worn, also were enlarged but were hyperopic owing to a severe flattening of the cornea. This hyperopia was slow to develop compared to the myopia produced in the diurnally reared visually restricted eyes. Finally, the shape of the posterior globe of these hyperopic eyes was no different from that of normal eyes.

Animals↗
PubMed1978

Refractive keratoplasty: keratophakia and keratomileusis.

We have presented our early experience with the refractive keratoplasty techniques of Doctor Jose Barraquer--keratophakia and hypermetropic keratomileusis. In contradistinction to the alloplastic lens substitutes currently being employed for the integral correction of aphakia, his techniques would seem to offer a more permanent, more physiologic, full-time optical correction of the aphakic state. Their use is limited only by the condition of the patient's corneaa and, in fact, may be applied not only in aphakia but also in phakic eyes with higher degrees of hyperopia or myopia. In the opinion of the authors, the refractive keratoplasty techniques of Barraquer can be perfored by any well-instructed ophthalmic surgeon. These techniques offer to many patients a satisfactory and potentially a physiologically superior alternative to alloplastic lens substitute for aphakic correction.

Aged↗
PubMed1979

Dominantly inherited cystoid macular edema.

Four patients of Greek ancestry had dominantly inherited cystoid macular edema. Characteristics of this syndrome include the following: an early onset and prolonged course of cystoid changes in the macula, followed by atrophy of the macula in later stages. Some patients also show leakage of fluorescein from the optic disc capillaries, subnormal EOG Lp/Dt ratios, elevated rod dark adaptation thresholds, red-green and blue-yellow color deficiencies, normal ERG findings, hyperopia, peripheral pigmentary retinopathy, and vitreous opacities. Dominantly inherited cystoid macular edema is a distinct genetic trait among the dominantly inherited macular dystrophies.

Adult↗
PubMed1979

[Variations in the muscular insertion, the course and elasticity of the muscles in people suffering from squint (author's transl)].

Variations in the area of the insertions of the rectus muscles are quite often observed. We have been paying more attention to these changes during the past year, and therefore we measured the distance of insertion from the corneal limbus during 310 squint operations. Furthermore we noted the width of the tendon at the insertion, atypical forms of insertions and finally we tried to evaluate the factor of muscular elasticity. The findings are as follows: 1. The arithmetical mean of the distance of insertion from the limbus was slightly less than cited in literature on this subject. It was not unusual to find variations of up to 4mm, even between the same muscles of both eyes. This seems to have little influence on the primary position and on the success of surgical interventions; when they do not exceed the measures cited in our paper. The relatively great area of contact will balance these variations. 2. We could not find a correlation between anomalies of refraction and the distance of insertions of the limbus. The insertions of higher degree hyperopia was not closer to the limbus. 3. The arithmetical mean of the width of tendon conformed to the values as shown in the literature. A range up to 8 mm for the medial rectus, up to 5,5 mm for the lateral rectus and up to 2,5 mm for the vertical rectus were observed. 4. We could see variations of the insertions: upward and downward and furthermore different lines of insertions: arched and step-like. These anomalies were found 52 times among the 310 muscles measured. 5. An increased muscular rigidity was felt in 56 medial rectus and in 13 lateral rectus muscels. In 21 cases the course of the horizontal muscles was atypical, i.e., they ran from below diagonally out of the orbita.

Child, Preschool↗
PubMed1979

Symposium: Clinical management of physiologic myopia. Introduction.

Myopia is not a cause of serious disease, although the two are sometimes associated. In contrast to hyperopia, it is a symptom and is easily understood. Myopia can have social as well as physical effects. Myopic patients often fear that they have increased their refractive error by their own behavior. This belief is enhanced by practitioners who subscribe to environmental theories and therapies.

Adolescent↗
PubMed1983

Comparison of atropine and tropicamide in esotropia.

Forty-one patients with esodeviation (82 eyes) were subjected first to 1% tropicamide and retinoscopy and then to retinoscopy after the use of 0.5% to 1% atropine sulfate in children with esodeviation up to the age of 5 years. The ages ranged from 2 months to 5 years, and the esodeviation ranged from 5 to 50 diopters (D). There were 20 male and 21 female patients. The average difference in the cycloplegia showed +.80 D more hyperopia with atropine than with tropicamide therapy. This was believed to be important, particularly in the young age group with esodeviation.

Atropine↗
PubMed1982

Refractive keratoplasty. Keratophakia and keratomileusis.

Early experience with the refractive keratoplasty techniques of José Barraquer--keratophakia and hypermetropic keratomileusis is presented. In contradistinction to the alloplastic lens substitutes currently being employed for the integral correction of aphakia, Barraquer's techniques would seem to offer a more permanent, more physiologic, full-time optical correction of the aphakic state. Their use is limited only by the condition of the patient's cornea and, in fact, may be applied not only in aphakia but also in phakic eyes with higher degrees of hyperopia or myopia. In the opinion of the authors, the refractive keratoplasty techniques of Barraquer can be performed by any well-instructed ophthalmic surgeon. These techniques offer to many patients a satisfactory, and potentially a physiologically superior alternative to alloplastic lens substitute for aphakic correction.

Aged↗
PubMed1983

[Congenital malformation of the pigment epithelium and retina].

A case of congenital malformation of the retina and of the pigment epithelium is reported, the lesion presenting as a slightly elevated greenish-blue lesion in the macular area or retinal periphery. The outer portion was hyperpigmented, the nonpigmented inner portion consisting of malformed thickened retina. Marked vascular tortuosity resulted from disturbance of the retinal layers and the presence of preretinal membrane. The lesion was detected in a boy with strabismus, loss of visual acuity and hyperopia, and is often misdiagnosed as tumor.

Child↗
PubMed1980

Relaxing incision for control of postoperative astigmatism following keratoplasty.

A new technique has been presented which provides a second surgical approach to correct excessive residual astigmatism following keratoplasty. The relaxing incision procedure has advantages over wedge resection in that it can be performed at the slit lamp, it gives no initial overcorrection, and it has a much shorter postoperative course while giving rapid results without suturing. Since this technique does not appear to produce significant hyperopia and may produce a tendency toward myopia, the corneal surgeon would thus have alternative techniques from which to choose, depending, in part, on the spherical component of the refraction.

Astigmatism↗
PubMed1982

On the significance of heterophoria for stereoscopic vision.

This study was undertaken to explain the possible correlation between heterophoria and stereopsis because, in the literature, there are different opinions. The subjects were 806 recruits. They were trained as rangefinder men, of whom a perfect stereopsis is required. The permitted maximal limits of heterophoria were 1 prism diopter (PrD) vertically, of esophoria 5 PrD, and of exophoria 6 PrD. Soldiers wit abnormal stereopsis, myopia, hyperopia more than 1.75, or astigmatism over 0.50 diopters, were omitted. The heterophoria was tested with Herschel's prism to 5 m distance. The stereoscopic vision was investigated using Pulfrich's device and the so-called three-needle test. No statistically significant correlation could be demonstrated between heterophoria and the degree of stereopsis. Surprisingly, it could be noticed that persons with esopheria finshed Pulfrich's test more quickly than those with exophoria. This difference was statistically highly significant. In the three-needle test, the results had the same trend. This might have some importance to rangefinder men and to pilots if it can be confirmed in the military practice.

Adult↗
PubMed1995

A retrospective study of eye disease among first grade children in Los Angeles.

BACKGROUND: The prevalence of ocular disease among children in one school district in Los Angeles, California was studied to better understand the types of eye disorders among this population as well as to develop appropriate preventive programs. METHODS: A computer-assisted retrospective analysis of date was performed from charts of 2,204 first grade children examined in the UCLA Mobile Eye Clinic. RESULTS: One or more ocular disorders were observed in 22.3 percent of the subjects. Uncorrected best monocular visual acuity was 20/40 or worse in 3.4 percent of the children. Refractive errors were diagnosed in 15.7 percent of the subjects, astigmatism in 7.6 percent, hyperopia in 6.2 percent, and myopia in 6.0 percent. Color vision deficiencies (red-green) were found in 2.6 percent of boys. The prevalences of heterophorias and heterotropias were 1.2 percent and 1.3 percent, respectively. CONCLUSIONS: The variety of ocular disorders diagnosed in this demographic setting attests to the importance of performing early and effective screening eye examinations for children.

Child↗
PubMedDate not supplied

Noncontact laser photothermal keratoplasty. I: Biophysical principles and laser beam delivery system.

BACKGROUND: Thermal shrinkage of stromal collagen is known to produce changes in the corneal curvature. We designed a novel, noncontact laser beam delivery system to perform laser photothermal keratoplasty. MATERIALS AND METHODS: The instrument consisted of a pulsed holmium:YAG laser (2.10-micrometer wavelength, 250-microsecond pulse width, 5-hertz repetition rate) coupled via a monofilament fiber to a common slit-lamp microscope equipped with a polyprism, an adjustable mask, and a projection lens. The system projected an 8-spot annular pattern of infrared laser energy on the cornea to achieve a thermal profile within the stroma and to attain controlled, predictable collagen shrinkage. The system produced treatment patterns of 8 to 32 spots of 150 to 600 microns diameter in concentric rings, continuously adjustable between 3 and 7 mm. The versatility of the system in creating different treatment patterns was tested on thermal paper and human cadaver eyes. RESULTS: A uniform beam profile and different treatment patterns for myopia, hyperopia, and astigmatism were obtained. Myopic correction of 6.00 diopters was demonstrated on cadaver eyes. Corneal topography documented corneal flattening (> 6.00 D) with the following treatment parameters: each spot size on the cornea = 300 microns, radiant exposure of each spot = 18.0 J/cm2, number of pulses = 1, diameter of the treatment ring = 3 mm. CONCLUSIONS: Noncontact slit-lamp microscope laser delivery system for laser photothermal keratoplasty provides flexible and precise selection of laser treatment parameters. It may improve the efficacy of the procedure.

Cadaver↗
PubMedDate not supplied

Noncontact laser photothermal keratoplasty. II: Refractive effects and treatment parameters in cadaver eyes.

BACKGROUND: Noncontact laser photothermal keratoplasty may provide a new alternative for the treatment of myopia, hyperopia, and astigmatism. The purpose of this article is to study the refractive effect that laser photoablation keratoplasty is capable of producing on a normal human cadaver cornea, including the relationship between the keratometric changes and laser treatment parameters. METHODS: The human cadaver eyes were treated with a holmium laser (pulsed Ho:YAG, 2.10 microns, 250 microseconds) coupled to a maskable, polyprismatic delivery system mounted on either an optical bench or a slit-lamp microscope. Using a topographic videokeratography system, we first investigated the refractive effect that noncontact laser photothermal keratoplasty would produce on a normal cadaver cornea. We then studied the keratometric changes produced by different radiant exposure levels at a fixed treatment pattern, as well as by different treatment patterns at a fixed radiant exposure level. Finally, we studied the possible therapeutic application of laser photothermal keratoplasty for correcting high postoperative astigmatism on a cadaver eye model. RESULTS: For the single-pulse 3-millimeter ring of eight-spot treatment, the keratometric power of the cornea initially increased with the radiant exposure and peaked at 26 J/cm2. The refractive effect was increased by projecting an additional set of eight spots equidistant between the first eight spots on the same diameter ring. Eighteen J/cm2 was the minimal radiant exposure required to produce consistent and predictable keratometric changes. The corneas were flattened using treatment patterns smaller than or equal to 3 mm in diameter and steepened using treatment patterns larger than or equal to 5 mm in diameter. A transition zone between 4 and 5 mm was observed in which minimal and unpredictable keratometric changes of the central cornea occurred. The surgically-induced astigmatism (> 10.00 D) was corrected by progressive laser photothermal keratoplasty treatments. CONCLUSIONS: Laser photothermal keratoplasty can acutely steepen and flatten the cornea in human cadaver eyes.

Astigmatism↗
PubMed1995

Results of reshaping with the 193-nm excimer laser.

We report herein our experience with reshaping following primary photorefractive keratectomy (PRK). Reshaping was performed on 7 of 116 myopic eyes (6 patients) 6-12 months subsequent to initial treatment. We carried out reshaping on 5 eyes (4 patients) for either undercorrection or regression. The mean preoperative refraction was -6.9 D, and at 1 year postsurgery it was -0.3 D. At 6 months following reshaping, the mean refraction was -0.15 D and the average uncorrected visual acuity (VA) was 20/25. In one patient, retreatment was performed 6 months after initial PRK due to marked regression and deterioration of VA. At 9 months subsequent to reshaping, the VA had improved to 20/25 with spherical correction of -1.0 D. In another patient, the best corrected VA deterioriated from 20/40 (-13.5 D) to 20/80, with hyperopia of +3.5 D being combined with marked scarring. At 6 months following phototherapeutic keratectomy (PTK), the VA had improved to 20/50, with spherical correction of +1.0 D. In conclusion, these observations demonstrate that reshaping is a satisfactory mode of treatment in certain indications.

Adult↗
PubMed1993

Refractive error and choroidal perfusion characteristics in patients with choroidal neovascularization and age-related macular degeneration.

The refractive error of 186 eyes with choroidal neovascularization (CNV) secondary to age-related macular degeneration (ARMD) was determined. It was found that the risk for the development of this form of ARMD increased with increasing degrees of hyperopia. The 96 patients afflicted with bilateral CNV were significantly older than the unilaterally affected patients (P = 0.027). Abnormal choroidal perfusion was identified in 66.4% of the fluorescein angiograms. These findings support the concept that hyperopic shortening in eyes afflicted with ARMD might cause secondary changes in the choroidal vasculature, predisposing them to choroidal neovascularization.

Aged↗