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PubMed1990

[Focal macular electroretinogram in high myopia].

To investigate early changes of the macula in eyes with myopia, we compared 66 eyes with high myopia with 76 normal eyes by recording focal macular electroretinogram (ERG). The eyes with high myopia were divided into two groups; eyes showing only tigroid fundus (group 1) and those associated with posterior staphyloma involving the macula (group 2). The visual acuity of groups 1 and 2 was 1, 0 or better and 0.8 or better, respectively. The amplitude of the a-wave, b-wave in group 1 was significantly smaller than that of normal eyes, however the peak latency was within the normal range. The amplitude of a-wave, b-wave and oscillatory potentials in group 2 was significantly smaller and the peak latency was significantly longer than those in group 1. The abnormal amplitude with normal peak latency in group 1 suggests some reduction of numbers of cones, which is considered to be an early pathologic change in the macula with high myopia. The more reduced amplitude with delayed peak latency in group 2 suggests that, in the advanced stage, the macular pathologic finding includes some quantitative damage as well as further reduction of macular cones.

Adolescent↗
PubMedDate not supplied

[The characteristics of the course of diabetic retinopathy in myopia].

A total of 220 diabetics (428 eyes) aged 16 to 79, 144 females and 76 males, have been examined to define the incidence rate and the clinical manifestations of diabetic involvement of the retina. There were 88 eyes with myopia, 142 with hypermetropia, and 198 with emmetropia. Diabetic changes of the retina were detected in 40.9% of myopic refraction cases, in 65.2% of emmetropia and in 70.4% of hypermetropia cases. The severity of the involvement was lesser in myopia than in other types of refraction. In medium-severity myopia no proliferative stages of diabetic retinopathy were observed, and in high myopia (10 eyes) no diabetic involvements of the fundus oculi were revealed. In anisometropia diabetic symptoms on the myopic side were either absent or poorly manifest. These findings point to the role of intraocular status in the pathogenesis of diabetic involvement of the retina and their progress.

Adolescent↗
PubMed1990

[Role of heredity in myopia].

Analysis of genealogic data of 100 patients addressed on occasion of myopia in 1987-1988 has shown that in 85% of the subjects myopia was of a clearly hereditary character (in 35%--a dominant and in 50%--a recessive hereditary). The author compares his own results with literature data and draws attention to Steiger's views about formation of myopic refraction and the role of hereditary factor in this process. In the light of the mentioned data, the author considers it expedient to work out a programme of special researches for development of a method of prognosticating initial myopia and a correction of several ways for approbation of existing methods of prevention of progressive myopia.

Adolescent↗
PubMed1990

[The relationship of structure in vivo of low tension glaucoma and myopia].

The structure in vivo and incidence of myopia on thirty patients with low tension glaucoma were studied in this paper. Results showed that the incidence of high myopia of patients with low tension glaucoma was higher than normal. All of the mean values of the thickness of lens, the length of vitreous and axis, and the area of optic disc were larger than normal too. These indicate that patients with low tension glaucoma may often be associated with high myopia, and their structure of eye in vivo differs from normal. These may be related to pathogenesis of disease with low tension glaucoma. The relationship of myopia and structure of optic disc with glaucoma were briefly summarized.

Adult↗
PubMed1989

[Accommodative hyperemia of the ciliary body as one of the pathogenetic factors in myopia].

Thermometry of 40 eyes before and after visual work at near with different correction of ametropia and tonography of 20 eyes with progressive myopia and 20 eyes with stationary myopia conducted before and after 15-minute reading load under full correction have revealed that visual work at near is accompanied by working hyperemia of ciliary body (rise of temperature in the anterior segment of the eye ball) and hyperproduction of intraocular fluid. In eyes with stationary myopia, hyperproduction is fully compensated by improvement of aqueous outflow from the eye. In eyes with progressive myopia, ophthalmic hypertension takes place because of insufficient improvement of the outflow facility coefficient. It is likely that working hyperemia of the ciliary body and hyperproduction of intraocular fluid under conditions of visual work at near can be realized as a factor of myopization of the human eye in case of a certain predisposition: in eyes with a not fully formed angle of the anterior chamber or in eyes with anomalous development of the angle.

Accommodation, Ocular↗
PubMed1989

Refractive and structural measures of lid-suture myopia in tree shrew.

In order to study more thoroughly the refractive and structural changes associated with lid-suture myopia, five tree shrews were raised for approximately 16 weeks with monocular visual experience produced by lid closure. Four animals raised with normal laboratory visual experience served as a control group. Compared to the paired open eye, lid-sutured eyes were myopic (-12.1 +/- 6.3 diopters by retinoscopy), corneas were flatter (0.26 +/- 0.18 mm radius increase by photokeratometry) and axial lengths were greater (0.32 +/- 0.17 mm longer by A-scan ultrasonography). The axial length increase was due to elongation of the vitreous chamber (0.38 +/- 0.19 mm longer by A-scan ultrasonography). The open eyes of experimental animals were not significantly different than the normal eyes of control animals. Two of these treatment effects, namely, refractive state changes and axial length increases, were demonstrated with independent techniques: streak retinoscopy was compared to coincidence optometry, and A-scan ultrasound was compared to axial measurements of photographs of frozen, sectioned eyes. The three main ocular effects of eyelid closure were stable over three measurement sessions completed within a 4 week period. Additional refractive and A-scan measurements taken 7.5 months later showed no significant changes. Optical modelling showed that the observed myopia of the lid-sutured eye is consistent with the observed elongation of the vitreous chamber coupled with the flattened cornea although other changes could not be ruled out. We conclude that an axial myopia is produced reliably in tree shrews by raising them with eyelid closure and that the measurement techniques used in this study have sufficient resolution to study the development of myopia in this species.

Animals↗
PubMed1989

A review of the prevalence and causes of myopia.

In this study, we reviewed the prevalence of myopia by country. Different types of myopia are elaborated and the causes of myopia are presented. It appears that the origin of myopia is due to both environmental and genetic factors.

Animals↗
PubMed1989

[The surgical results in progressive myopia in children].

The paper analyses effectiveness of surgical treatment on occasion of progressive myopia in 96 children (180 eyes), aged from 5 to 14 years, depending on the patient's age, the form of myopia (congenital, acquired). Scleroplasty was made after the method of N. N. Pivovarov et al. Remote results, from 1 to 1.5 years, have shown stabilization of myopia in 90% of cases. Absolute and relative indications to surgical treatment of myopia are shown. The necessity of further studying of the mechanism and effectiveness of scleroplasty in children is substantiated.

Adolescent↗
PubMed1989

[An analysis of the late results of scleroplasty in progressive myopia].

Analysis of remote (to 9 years) results after 256 sclera-enhancing operations in patients with progressive myopia, aged from 7 to 48 years, revealed stabilization of the process in 72% of patients, the dependence of the effect on the form of myopia and the patient's age. As to prognosis, early acquired myopia and the children age are less favourable. The number of surgical failures increases in remote terms; in some patients the effect can be transitory. Therefore, surgical results should be judged about minimum 3 years after operation. Comparative examination of the state of a complex "graft-sclera" by means of computer tomography in satisfactory and unsatisfactory surgical results has shown that myopia continues to progress, as a rule, in case of reduced scleral density and the absence of roentgenologic signs of the graft. The action of scleroplasty on the appearance and course of central chorioretinal dystrophies has been studied.

Adolescent↗
PubMed1988

A metabolic analysis of high myopia and senile macular degeneration.

Abnormal zinc and copper metabolism have been described in several retinal disorders affecting the retinal pigment epithelium. An infrequent presentation of senile macular degeneration in high myopia is well known. We examined the blood for zinc and copper and the urine for copper of three groups of patients, one consisting of high myopia, another with high myopia and primary retinal detachment and the other a group of patients with senile macular degeneration. When comparing the above groups of patients, we found statistically elevated values of serum zinc (p = less than 0.005) in the group of patients with senile macular degeneration. The significance of these findings, and a correlation with the pathogeneses of high myopia and senile macular degeneration is discussed.

Adult↗
PubMed1987

Staphyloma and other risk factors in axial myopia.

Posterior staphyloma, associated exclusively with axial myopia, is progressive and often results in visual loss. Five types of primary staphyloma have been described anatomically and in terms of sequelae. Mechanical and physiological factors in axial myopia can lead to potentially sight-threatening abnormalities which affect central or peripheral vision. Some are easily detectable while others require a thorough evaluation of the peripheral retina. This report consists of a review of fundus changes associated with axial myopia, the types of staphyloma, and a case report. Emphasis is placed on identification and management of patients at risk from the sequelae of axial myopia.

Choroid↗
PubMed1985

The Houston myopia control study: a preliminary report by the patient care team.

The Houston Myopia Control Study is a 3-year randomized clinical trial designed to test the efficacy of bifocal lenses for the control of myopia. Each of 213 myopic subjects, between the ages of 6 and 15 years, was placed in either a single vision (standard treatment) group, a +1.00 D. add group, or a +2.00 D. add group, by means of a table of random numbers. Subjects in each of the 3 groups were matched on the basis of sex, age, and the amount of myopia. Subjects were accepted into the study during an 18-month period ending in September, 1982, so all subjects will have completed the study by September, 1985. The purpose of this preliminary report is to inform optometrists of the existence of the study and to discuss the factors that must be taken into consideration when designing a randomized clinical trial making use of bifocal lenses for the control of myopia.

Accommodation, Ocular↗
PubMed1985

Houston Myopia Control Study: a randomized clinical trial. Part I. Background and design of the study.

The Houston Myopia Control Study is a 3-year randomized clinical trial in which each of 213 myopic children was placed in either a single vision (standard treatment) group, a +1.00 D add treatment group, or a +2.00 D add treatment group, on the basis of a randomized procedure. Subjects for the three treatment groups were matched on the basis of sex, age, and the initial amount of myopia. The study involves two groups of investigators: an evaluation team, whose task has been to evaluate candidates before entering the study and to reevaluate each subject on a yearly basis for the 3-year period, and a patient care team, whose task has been to prescribe glasses for each subject as well as to counsel subjects and their parents in the correct use of the glasses and to provide a follow-up examination every six months for the duration of the study. Once the glasses had been prescribed, members of the evaluation team were not permitted to know which subjects wore single vision lenses and which wore bifocals. In the interest of good patient care, members of the patient care team knew which subjects wore single vision lenses and which wore +1.00 D add or +2.00 D add bifocals. In this report, the authors discuss theories concerning the etiology of myopia, methods that have been used in an attempt to control the progression of myopia, and the design of the current study. Further reports will present the results of the study on the basis of the data collected by each of the two study teams.

Adolescent↗
PubMed1983

Transient myopia following isosorbide dinitrate.

A 38-year-old white woman consistently developed transient myopia following the administration of isosorbide dinitrate (Isordil). The myopia was associated with a decreased amplitude of accommodation, a reduction of the AC/A ratio and was eliminated by cycloplegia. Ciliary spasm secondary to the ingestion of this medication is proposed as a possible explanation for the transient myopia. To our knowledge, this case represents the first case of transient myopia following isosorbide dinitrate administration.

Accommodation, Ocular↗
PubMedDate not supplied

Retreatment of undercorrected photorefractive keratectomy for myopia.

Fourteen eyes treated by photorefractive keratectomy (PRK) for myopia required retreatment because of undercorrection. The mean preoperative refraction of these eyes had been -9.82 D (range 5.25 to 17.13). No eyes before photorefractive keratectomy had low myopia, three eyes had myopia between -3.10 and -6.00 D, four were between -6.10 and -10.00 D, and seven had more than -10.00 D of myopia. Retreatment was required for manifest scars in association with regression, unresponsive to topical corticosteroids. The retreatments were performed using a Summit ExciMed UV200LA excimer laser with a dual ablation technique utilizing a phototherapeutic keratectomy followed by a photorefractive keratectomy. Follow-up ranged from 1 to 9 months. Eight eyes followed more than 3 months had a mean spherical equivalent refraction of -0.58 D (range -7.35 to +1.25).

Cornea↗
PubMedDate not supplied

Photorefractive keratectomy for myopia: one-year follow-up in 97 eyes.

We made a comprehensive study of 97 eyes that received photorefractive keratectomy (PRK) for myopia and followed them for one year. In 95 eyes, uncorrected visual acuity improved and best-corrected acuity remained unchanged. In eyes with myopia of more than -3.0 diopters (D), the postoperative refraction was within -1.0 D of attempted correction. Predictability decreased with higher myopia. We also examined the changes of both epithelium and endothelium with the specular microscope and found no significant changes after photorefractive keratectomy. Videokeratography showed an average of inferior decentration in most eyes by 0.51 mm +/- 0.31 (n = 60); only one clinical problem was noted--one eye experienced monocular diplopia for seven months. Pachometry showed a small percentage had corneal thinning--the amount depended on the degree of myopia. A rise in intraocular pressure over 21 mm Hg was observed in 8.9% of eyes but it was controlled without surgery. Haze was observed in most eyes, but faded gradually without significant problems. Reduced contrast sensitivity in night vision was noted and some patients experienced glare. Day vision contrast sensitivity was related to corneal haze.

Adolescent↗
PubMed1994

[Pseudo-esotropia caused by nasal dislocation of the macula in patients with high infantile myopia].

Pseudostrabismus due to dislocation of the macula is a well-known clinical entity mostly reported in the outward, upward and downward directions. This heterotopia is thought to be caused by changes in the growth rate in different areas of the retina or mechanically by retinal traction due to abortive ROP, vascular abnormalities, chorioiditis or other peripheral retinal disorders. In this paper we demonstrate four cases of macular dislocation in the direction of the optic disc associated with high myopia in infants and toddlers without signs of other retinal abnormalities. These children had myopia had myopia ranging from -17 to -20 D and esotropia superimposed by pseudostrabismus. In all four cases, strabismus surgery was performed. Postoperatively, these children showed signs of some binocular interaction. This case report may indicate that in children with strabismus associated with high myopia macular dislocation should be considered as a further characteristic affecting diagnosis and therapy.

Child↗
PubMed1993

[Excimer laser photorefractive keratectomy for myopia].

We have used excimer laser during the past year to correct refractive errors (myopia and hypermetropia) and to remove superficial corneal scars. 714 eyes underwent excimer laser photorefractive keratectomy for correction of myopia and 81% of the patients achieved uncorrected visual acuity of 6/12 or better without glasses. 17 patients underwent a second treatment to correct residual myopia and all of them had uncorrected visual acuity of 6/12 or better 6 months later. The results show that excimer laser photorefractive keratectomy is a safe and efficient procedure to correct myopia. The possibility of various postoperative complications appearing over the long term suggests cautious optimism.

Cornea↗