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PubMed1997

[Methodological approaches to correcting myopia in flight personnel].

Myopia as the main reason of disqualification of the pilots meets in 2.7% of cases from number of all certificates and in 17% serves the main reason of restriction in flying work. The authors offer a new technique of correction of myopia in pilots, based on principles of the complex approach: the primary visual status at choice of a method of correction; the estimation of efficiency of correction is founded on the professional visual testing; the adverse conditions of activity of a pilot influence on a choice of a method of correction. The authors estimate efficiency of three methods of correction of myopia in the pilots: anterior dosed radial keratotomy, direct electrical ophthalmostimulation (DEOS) and contact correction, formulate an experts' report about efficiency of application of DEOS and contact lenses, prove a conducting role of contact correction in system of medical and professional rehabilitation of flying personnel with myopia.

Aerospace Medicine↗
PubMed1997

[The significance of myopia and birth weight in prematurity].

AIM: The relation between myopia and birth weight of premature newborns was assessed in this study. MATERIAL AND METHODS: There were 90 children (180 eyes) involved in the study, their birth weight ranged between 580 and 2450 g (mean 1698), and myopia ranged from -1.5 to -22.5 D (mean -9.8 D). Children were divided into two groups: group I: 38 children (76 eyes) with birth weight from 580 to 1500 g (mean 1158 g), group II: 52 children (104 eyes) with birth weight from 1501 to 2450 g (mean 2093 g). Mean value of myopia in group I was -10.4 D and -9.4 D in group II. RESULTS: The results were assessed with Statgraphics software. The analysis of mean values regression showed no relation between myopia and birth weight in group I (regression coefficient b = 0.003, p = 0.24) and no relation in group II (regression coefficient b = 0.008, p = 0.016) at significance level alpha = 0.01.

Adolescent↗
PubMed1997

[Why and how to correct myopia?].

The myopia and its aggravation depend on genetic and environmental factors. Experiences performed on monkeys and chickens indicate that the quality of the image affects the growth on the ocular globe in the young animal by modifying biochemical conditions at the retinal level. If near work seems to be a factor associated to the myopia, the role of sustained accommodation on the evolution of the former is not evident. The correction of the myopia by glasses can be made with the help of different materials that will be chosen according to the importance of the myopia, the morphology of the face, the priority of the esthetics or the security.

Accommodation, Ocular↗
PubMed1996

Relationship between myopia and optical components--a study among Chinese Hong Kong student population.

PURPOSE: To establish the prevalence and severity of myopia among the Chinese Hong Kong students and to study the relationship between myopia and optical components. METHODS: One thousand and seventy-five freshmen of the 1993-1994 academic year in the Chinese University of Hong Kong underwent the eye examination including evaluation of refractive error, keratometry, and A-scan ultrasonic biometry. The data were analyzed with the SPSS/PC+4.01 statistical package. RESULTS: The prevalence of myopia was 91.7% with the mean refraction being -4.00 +/- 2.64D in this young adult population. The statistical analyses demonstrated a significant correlation between refractive value and axial length of the globe (r = -0.78), vitreous length (r = -0.76), anterior chamber depth (r = -0.33), lens thickness (r = 0.13) and corneal curvature (r = 0.19). CONCLUSION: The refractive status is mainly dependent on the axial length. In general, the higher the myopia was, the longer the eyeball, the deeper the anterior chamber, the steeper the cornea, and the thinner the lens would be.

Adolescent↗
PubMed1996

Corneal topography research of myopia in Chinese.

PURPOSE: To determine corneal topography parameters of myopia in Chinese and help for studies of causes of myopia, distingiush other corneal diseases (such as early keratoconus), further explore the accurateness and safeness of the clinical effects of radil keratotomy (RK) or photorefractive keratectomy (PRK). METHODS: Fifty-eight eyes with mild or moderate myopia were examined by computer-assisted photokeratography. (TMS-1 Computed Anatomy Inc. New York. NY) RESULTS: The corneal topography of most (68%) of the examined eyes showed symmetric bowtie pattern: the corneal surface of most (75%) of the examined eyes showed positive aspheric shape (steeper centrally, flatter peripherally); the refractive power of central cornea is at mean 44.165 +/- 1.429 D; the refractive difference between 1 to 25 ring in keratoscpe was at mean 1.655 +/- 0.785D; the mean SRI was 0.558 +/- 0.768, the mean SAI was 0.296 +/- 0.149; the mean Smik was 44.209 +/- 1.515D. The apex and visual axis were dislocation in all the cornea examined. CONCLUSIONS: The corneal surface refractive characterization of myopia might be relative to the clinical effects of RK or PRK.

Adolescent↗
PubMed1997

[Laser scanning laser ophthalmoscopy in diagnosis of juvenile glaucoma cases with myopia].

UNLABELLED: The diagnosis of the open angle glaucoma in myopic eyes remains one of the major problems, as the changes of the optic head in myopia may be similar to glaucomatous changes. The aim of the study was to analyse biomorphometric parameters of the optic nerve head in myopic eyes with glaucoma with scanning laser ophthalmoscope from Laser Diagnostic Technologies Inc. There was 29 children examined and among them 12 children with glaucoma and myopia as a study group (I) and 17 children with myopia as a control group (II). RESULTS: TCA means values; group I: 1.994 +/- 0.158, group II:2.028 +/- 0.200 CD means values; group I; 0.315 +/- 0.072, group II: 0.247 +/- 0.057 Rim means values; group I: 1.366 +/- 0.164, group II: 1.511 +/- 0.136 Vol. A mean values; group I: +0.205 +/- 0.03, group II: +0.83 +/- 0.03 Vol. B mean values; group I: -0.159 +/- 1.608, group II: -0.117 +/- 0.08. Average values of the biomorphometric parameters of the optic nerve head were worse in group I than in group II, but there was not statistical significance between the differences. Scanning laser ophthalmoscopy may be used as very important additional examination in juvenile glaucoma cases with myopia.

Adolescent↗
PubMed1998

[Scleroplasty surgery in the treatment of progressive myopia in children].

The authors evaluate the results of 257 scleroplastic operations performed in 145 children with progressive myopia in 1989-1995. The age range of the operated children was 5-17 years. The mean age at the time of operation was 10.4 +/- 3.9 years. The children were followed up for at least two years before and two years after operation. All children met the condition of progressive myopia, minimal refraction -6.0 D and progression of at least 1 D per year during the last two years before surgery. The authors investigated the axial length of the bulbus by biometry, objective and subjective refraction, the best corrected visual acuity before and after surgery. The mean progression of myopia two years after the scleroplastic operation declined to a mean value of 0.29/year. No serious complications were recorded. Scleroplasty can be considered a safe surgical method which can help to improve the unfavourable development of progressive myopia.

Adolescent↗
PubMed1998

Two-year results of photorefractive keratectomy with scanning spot ablation for myopia of less than -6.0 diopters.

BACKGROUND AND OBJECTIVE: To investigate the efficacy, predictability, stability, and safety of photorefractive keratectomy (PRK) with scanning spot ablation for the treatment of myopia of less than -6.0 D. PATIENTS AND METHODS: Twenty eyes of 20 patients (11 men, 9 women) were enrolled into the study. The mean age was 26.2 +/- 5.4 years. Mean spherical equivalent myopia was -3.53 +/- 1.13 D, ranging from -2.25 to -6.00 D. Patients underwent excimer laser PRK for the treatment of myopia. Follow-up time was at least 24 months in all patients. RESULTS: Mean spherical equivalent refraction was +0.84 +/- 0.99 D at 1 month, +0.19 +/- 0.54 at 3 months, -0.01 +/- 0.53 at 12 months, and -0.13 +/- 0.50 at 24 months. There was a mean regression of 0.65 D between 1 and 3 months. At 24 months, 16 (80%) of the eyes remained within +0.50 D of emmetropia and 18 (90%) of the eyes remained within +/- 1.0 D of emmetropia. Nineteen (95%) of the eyes had uncorrected visual acuity of 20/40 or better. The mean corneal haze score was maximum at 3 months (0.88 +/- 0.22). There was no clinically significant corneal haze (greater than 2+). One eye (5%) lost 2 or more lines of best-corrected visual acuity. CONCLUSION: Excimer laser PRK with the scanning spot ablation technique is effective, predictable, stable, and safe for the treatment of myopia of less than -6.0 D.

Adult↗
PubMedDate not supplied

[Sclera-fortifying treatment of myopia in children at high risk of its progression].

The paper deals with progress of myopia during active growth of children. The strategy of treatment is developed and efficacy of surgical fortification of the sclera in children with an unfavorable course of myopia (early acquired myopia, rapid progress of the condition) is assessed. The proposed method stabilizes myopia for 3 years sclera fortification carried out in several stages in the patients with the most grave condition. Practical recommendations are offered concerning a certain order of exposures and indications for them.

Adolescent↗
PubMed1986

Instrument myopia conceptions, misconceptions, and influencing factors.

The literature on instrument myopia is reviewed, with the review organized around three principal objectives. One is to describe and discuss various factors that may influence the degree to which instrument myopia is manifested, including monocular vs. binocular viewing, age, direction of focus, illumination level, fatigue, magnification, astigmatic variations, optical decentration, perceived proximity of the target and peripheral surround, and experience. The second objective is to discuss the intermediate resting state conception of accommodation, its application to instrument myopia, and its strengths and weaknesses as applied to the available literature. The third objective is to summarize the salient problems in the instrument myopia literature, and to present a set of recommendations for guiding future work.

Accommodation, Ocular↗
PubMed2026

Association of long-term exposure to ambient air pollution and myopia in Chinese children.

Ambient air pollution is recognized as a major global health concern, but evidence on its association with childhood myopia remains limited, particularly under multi-pollutant exposure conditions. A school-based study was conducted in Tianjin, China, including 212,566 students in grades 4-6. The 3-yr mean concentrations of particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5), its major components (sulfate (SO42-), nitrate (NO3-), ammonium (NH4+), organic matter (OM), and black carbon (BC)), and ozone (O3) were estimated using machine-learning exposure models and linked to school locations. Restricted cubic splines and quartile-based modified Poisson models were used to assess single-pollutant exposure-response relationships, and quantile-based g-computation was applied to estimate joint pollutant associations. In single-pollutant models, the highest quartile of SO42- was associated with higher myopia prevalence compared with the lowest quartile (PR = 1.10; 95% CI, 1.07-1.13). O3 showed weaker and non-monotonic positive patterns (Q4 vs Q1: PR = 1.03; 95% CI, 1.00-1.05). In mixture analyses, a one-quartile increase in joint exposure was associated with higher myopia prevalence (PR = 1.017; 95% CI, 1.007-1.027). Sensitivity analyses generally supported the direction of the main findings. These findings suggest that long-term exposure to specific ambient air pollutants may be associated with myopia in school-aged children.

Chemical components↗
PubMed1982

[Accommodation as the primary cause of night myopia].

Night myopia can now be measured accurately with a laser optometer. An increasing number of reports, based on work with this optometer, have supported the hypothesis that night myopia is caused by accommodation. In this study subjects with one phakic and one aphakic eye were tested with respect to the magnitude of night myopia developed in each eye. The results appear to represent the first direct experimental evidence for the hypothesis that accommodation is the primary cause of night myopia.

Accommodation, Ocular↗
PubMed1999

Animal Models of Myopia: Learning How Vision Controls the Size of the Eye.

As they grow up, approximately 25% of children in the United States become myopic (nearsighted). A much smaller fraction become significantly hyperopic (farsighted), while the majority develop little or no refractive error and are emmetropic. The causes of refractive error, especially myopia, have been the subject of debate for more than a century. Some have held that myopia is primarily an inherited disorder, and others, that myopia is caused by protracted near work and, especially, by accommodation during protracted near work. It has not been possible, based solely on clinical observations, to resolve the relative roles of heredity versus environment in the development of refractive error. In the mid-1970s, several animal models were developed to study the mechanisms underlying refractive error. Using animal models, it was found that the visual environment exerts a powerful influence on refractive state by controlling the axial length of the eye during the postnatal developmental period. Although several species have been examined, three have emerged as primary models and have played complementary roles: tree shrews (mammals closely related to primates), chicks, and monkeys. Each has advantages and disadvantages. Collectively, research on animal models has provided evidence on three issues, namely that (1) the visual environment can produce refractive error; (2) an emmetropization mechanism normally guides eyes to low refractive error; and (3) under-accommodation, rather than excessive accommodation, may cause myopia. Two decades of research on animal models have provided criteria that may be used to evaluate the usefulness of additional species as models of emmetropization.

Journal Article↗
PubMed2003

Peripapillary detachment in pathologic myopia.

OBJECTIVE: To describe peripapillary detachment in pathologic myopia (PDPM), a newly recognized fundus lesion. DESIGN: Retrospective medical record review. METHODS: We evaluated a series of myopic eyes that had a yellow-orange elevation of the retina and retinal pigment epithelium at the inferior border of the myopic conus. RESULTS: Twenty eyes of 15 patients were identified during a 17-year period to have characteristic findings of PDPM. The mean age of the patients was 58 years. They were followed up for an average of 6 years. The mean spherical equivalent correction was -11.00 diopters (D) (range, -6.00 to -16.00 D). The mean axial length was 27.4 mm (range, 25.3-28.9 mm). In each case, ophthalmic coherence tomographic examination showed a localized detachment of the retinal pigment epithelium and retina corresponding to the PDPM lesion. During the follow-up period, the lesion remained stable in all cases except for 1. No apparent negative effect on visual function was noted. CONCLUSIONS: Peripapillary detachment in pathologic myopia is an asymptomatic, yellow-orange peripapillary detachment of the retinal pigment epithelium and retina in pathologic myopia. Recognition of this lesion is important to distinguish it from other fundus pathologic conditions, such as tumors or choroidal neovascularization, which require further investigation and treatment.

Adult↗
PubMed2004

Safety and efficacy of 2% pirenzepine ophthalmic gel in children with myopia: a 1-year, multicenter, double-masked, placebo-controlled parallel study.

OBJECTIVE: To evaluate the safety and efficacy of the relatively selective M(1) antagonist pirenzepine hydrochloride in slowing the progression of myopia in school-aged children. METHODS: This was a parallel-group, placebo-controlled, double-masked study in healthy children, aged 8 to 12 years, with a spherical equivalent of -0.75 to -4.00 diopters (D) and astigmatism of 1.00 D or less. Patients underwent a baseline complete eye examination and regular examinations during a 1-year period. The setting was 13 US academic clinics and private practices. Patients were randomized in a 2:1 ratio to receive 2% pirenzepine ophthalmic gel or a placebo control twice daily for 1 year. RESULTS: At study entry, the spherical equivalent was mean +/- SD -2.098 +/- 0.903 D for the pirenzepine group (n = 117) and -1.933 +/- 0.825 D for the placebo group (n = 57, P = .22). At 1 year, there was a mean increase in myopia of 0.26 D in the pirenzepine group vs 0.53 D in the placebo group (P < .001). No patients in the placebo group and 13 (11%) of 117 patients in the pirenzepine group discontinued participation in the study because of adverse effects (5 [4%] of 117 due to excessive antimuscarinic effects). CONCLUSIONS: Pirenzepine is effective and relatively safe in slowing the progression of myopia during a 1-year treatment period.

Child↗
PubMed2004

A randomized trial of the effects of rigid contact lenses on myopia progression.

OBJECTIVE: To compare the effects of rigid gas-permeable contact lenses (RGPs) and soft contact lenses (SCLs) on myopia progression in children. METHODS: We randomly assigned 116 subjects to wear RGPs or SCLs. Subjects underwent cycloplegic autorefraction, keratometry, and A-scan ultrasonographic axial length measurements at each annual visit. All analyses were conducted according to the original randomization assignment. The primary outcome measure was the 3-year change in spherical equivalent cycloplegic autorefraction. RESULTS: The mean +/- SD spherical equivalent cycloplegic refractive error progressed -1.56 +/- 0.95 diopters (D) for RGP wearers and -2.19 +/- 0.89 D for the SCL wearers during the 3 years of the study (analysis of covariance [ANCOVA], P<.001). The axial growth of the eyes was not significantly different between treatment groups (ANCOVA, P = .57). The steep corneal meridian of the RGP wearers steepened 0.62 +/- 0.60 D, and that of the SCL wearers steepened 0.88 +/- 0.57 D during the 3 years (ANCOVA, P = .01). CONCLUSIONS: The RGP wearers' myopia progressed less than that of the SCL wearers. The corneal curvature of the SCL wearers steepened more than that of the RGP wearers, but the axial growth was not significantly different between the groups. Most refractive error treatment effect was limited to the first year of the trial. The results of the study provide information for eye care practitioners to share with their patients, but they do not indicate that RGPs should be prescribed primarily for myopia control.

Child↗
PubMed2006

Axial length, myopia, and the severity of lens opacity at the time of cataract surgery.

OBJECTIVE: To investigate the relationship between axial length, myopia of the eye, and the severity of lens opacity at the time of cataract surgery. METHODS: We retrospectively reviewed a consecutive series of 198 eyes of patients aged older than 50 years at Fukui University Hospital (Fukui, Japan) from June 2004 to December 2005. Patient age at the time of surgery, axial length, spherical equivalent, and the subtypes and severity of cataract (as classified according to the modification of the Lens Opacities Classification System, version III) were recorded. RESULTS: Axial length was significantly associated with age at the time of cataract surgery (P<.001). Regarding the severity of nuclear cataract, a significant correlation was seen between a higher score of nuclear cataract and longer axial length (P<.001). The relationship between the severity of nuclear cataract and spherical equivalent at the time of surgery showed a significant association between grading nuclear color and nuclear opalescence 4-6 and higher myopia (P<.001). CONCLUSION: An increase in axial length or myopia of the eye was associated with a lower mean age at the time of surgery and higher grade of nuclear cataract.

Aged↗
PubMed1983

Prevalence of myopia in the United States.

Data from the 1971 to 1972 National Health and Nutrition Examination Survey were used to estimate myopia prevalence rates for persons in the United States between the ages of 12 and 54 years. When persons were classified by the refractive status of their right eye, 25% were myopic. Significantly lower prevalence rates were found for male subjects than for female subjects and for blacks than for whites. Myopia prevalence rose with family income and educational level. The importance of income and educational level may result from their association with near work, a factor that has been implicated in the pathogenesis of myopia.

Adolescent↗