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PubMed2000

[Clinical outcome after in situ laser keratomileusis (LASIK) for myopia: a series of 390 eyes].

PURPOSE: We report our personal experience with LASIK for myopia to study its efficacy, safety, predictability and stability for low, moderate and high myopia. PATIENTS AND METHODS: Between January 1996 and December 1997, 390 eyes were treated. Follow-up was 6 months for 254 and one year for 136. Initial myopia ranged from -1.5 to -16 diopters with a spherical equivalent of -8.49D. The surgical procedure with topical anesthesia used the Chiron ALK-E automated corneal shaper for the initial flap of 160 microns thick, and the Chiron Excimer Laser Keracor 117 Technolas with an active eye tracking system for the stromal photoablation. Preoperative refraction, uncorrected (UVA) and best corrected visual acuity (BCVA) were compared to postoperative results. RESULTS: They are reported overall and for sub-groups of myopia. (A<=-5 D, -5 D =20/40 at 6 months. Average UVA was 0.65 D at one year and was as better as preoperative myopia was lower (group A 0.65D, group B0.5 at 6 months). Mean spherical equivalent was +0.08 D at J1 and -1.02 D at one year (group A -0.8 D, group B -0.67 D, and group C -3.92 D). Safety was correct and only a few per and postoperative complications were observed with only two patients losing more than two lines of BCVA. Mean BCVA was 0.72 at one year. Predictability demonstrated that 90% of group A eyes were at +/-1 D from emmetropia and 74% in group B at 6 months. More than 95% of eyes were stable at 6 months and 90% at one year. CONCLUSION: LASIK is a safe and efficient surgical treatment for low, moderate and high myopia, and should be improved with new software and new corneal shapers.

Female↗
PubMed2000

Cross-sectional study of near-work and myopia in kindergarten children in Singapore.

INTRODUCTION: In view of the high and increasing myopia rates amongst young Singaporean children, we aimed to assess the relationship between near-work and myopia in 414 pre-school children aged 4 to 6 years. MATERIALS AND METHODS: We measured near-work indices such as tuition classes outside school and other possible risk factors via a questionnaire. We then measured myopia with a hand-held autorefractor. RESULTS: Children who had 3 or more hours per week of near-work classes outside school had a higher rate [odds ratio 1.39 (95% confidence interval 1.02, 2.53)] of myopia. CONCLUSIONS: This suggests that there may be an association between near-work and myopia, even at such a young age. Given the increasing emphasis on near-work in Singapore, it may be important to call for increased visual health awareness, although further studies will be needed to establish if near-work causes myopia.

Age Distribution↗
PubMed2001

Effect of myopia on frequency-doubling perimetry.

PURPOSE: To examine the effect of myopia, occasionally associated with glaucomatous eyes, on the results obtained by frequency-doubling perimetry (FDP). METHODS: Sixty emmetropic or myopic normal volunteers (mean age, 26.2 +/- 0.35 years, mean +/- SEM; range, 19-34) with good visual acuity and without glaucoma were divided into three groups. The groups were emmetropia to low-myopia (mean refractive error, -1.16 +/- 0.23 D), intermediate-myopia (-4.95 +/- 0.17 D), and high-myopia (-8.12 +/- 0.36 D; n = 20 each). All subjects were tested on the FDP full-threshold C-20 program and the Humphrey Field Analyzer (HFA; Humphrey, Dublin, CA) full-threshold program on one randomly selected eye. FDP and the HFA test were conducted with the subjects wearing their full distance correction and with their distance correction with appropriate additional correction for near, respectively. The calculated mean sensitivity (MS), mean deviation (MD), pattern standard deviation (PSD), and test durations for FDP and the HFA test for the three groups were compared using one-way analysis of variance. The relationship between the refractive error and MS, MD, or PSD was also analyzed by simple regression analysis. RESULTS: The MS and MD for the fields determined by the HFA decreased significantly as the refractive errors increased, but there were no significant differences in the MS, MD, and PSD for FDP between the three groups. There were no significant differences in the test durations between the three groups for both FDP and HFA testing. The refractive error was correlated with both MS and MD only for the fields determined by the HFA. CONCLUSIONS: The results showed that lens-corrected myopia does not alter the visual fields obtained by FDP, and FDP can therefore be used regardless of the presence of myopia.

Adult↗
PubMed2001

[Myopia: frequency of lattice degeneration and axial length].

OBJECTIVE: To evaluate the relationship between lattice retinal degeneration and axial length of the eye in different grades of myopia. MATERIAL AND METHODS: A sample of 200 eyes from 124 myopic patients was collected by chance. The average age was 34.8 years (20-50 years) and the myopia was between 0.5 and 20 diopters (D). The eyes were grouped according to the degree of refraction defect, the mean axial length of each group (Scan A) and the frequency of lattice retinal degeneration and the relationship between these variables was studied. The possible influence of age on our results was also considered. For the statistical analysis, the SAS 6.07 program with the variance analysis for quantitative variables, and chi(2) test for qualitative variables with a 5% significance were used. A multivariable linear regression model was also adjusted. RESULTS: The highest frequency of lattice retinal degeneration occurred in those myopia patients having more than 15 D, and also in the group of myopia patients between 3 and 6 D, but this did not show statistical significance when compared with the other myopic groups. If the axial length is assessed, a greater frequency of lattice retinal degeneration is also found when the axial length is 25-27 mm and 29-30 mm, which correspond, respectively, to myopias between 3-10 D and more than 15 D. When the multivariable linear regression model was adjusted, the axial length showed the existence of lattice retinal degeneration (beta 0.41 mm; p=0.08) adjusted by the number of diopters (beta 0.38 mm; p<0.001). The determination coefficient (r(2)) was also 0.86. CONCLUSIONS: The highest number of cases of lattice retinal degeneration was found for myopias with axial eye length between 29-30 mm (more than 15 D), and 25-27 mm (between 3-10 D).

Adult↗
PubMed2001

Structural and ultrastructural changes to the sclera in a mammalian model of high myopia.

PURPOSE: The development of high myopia is associated with scleral thinning and changes in the diameter of scleral collagen fibrils in humans. In the present study, the association between these scleral changes and the losses in scleral tissue that have previously been reported in animal models were investigated to determine the relationship between changes in collagen fibril architecture and thinning of the sclera in high myopia. METHODS: Myopia was induced in young tree shrews by monocular deprivation of pattern vision for short-term (12 days) or long-term (3-20 months) periods. Scleral tissue from normal animals over a wide age range (birth to 21 months) was also collected to provide data on the normal development of the sclera. Light and electron microscopy were used to measure scleral thickness and to determine the frequency distribution of collagen fibril diameters in the sclera. Tissue loss was monitored through measures of scleral dry weight. RESULTS: Significant scleral thinning and tissue loss, particularly at the posterior pole of the eye, were associated with ocular enlargement and myopia development after both short- and long-term treatments. However, collagen fibril diameter distribution was not significantly altered after short-term myopia treatment, whereas, from 3 months of monocular deprivation onward, significant reductions in the median collagen fibril diameter were noted, particularly at the posterior pole. CONCLUSIONS: The results of this study demonstrated that loss of scleral tissue and subsequent scleral thinning occurred rapidly during development of axial myopia. However, this initial tissue loss progressed in a way that did not result in significant alterations to the collagen fibril diameter distribution. In the longer term, there was an increased number of small diameter collagen fibrils in the sclera of highly myopic eyes, which is consistent with findings in humans and is likely to contribute to the weakened biomechanical properties of the sclera that have previously been reported.

Animals↗
PubMed1998

[The choice of intraocular lens before cataract extraction for cases with high myopia].

OBJECTIVE: To study the choice of diopter and size of optical portion of intraocular lens (IOL) before cataract extraction for cases with high myopia. METHODS: Extracapsular cataract extraction (ECCE) or phacoemulsification with IOL implantation was performed on 60 cases (94 eyes) with high myopia (axial length > 26mm). The posterior chamber IOL selected and inserted was the one with the diopter and size of the optical portion suitable for the recipient to have a postoperative low myopia and easy to be examined with an ophthalmoscope. RESULTS: The postoperative eyes were of low myopia, -2.07 +/- 1.95 D. The larger size of optical portion was more suitable for ocular fundus examination. Great care was taken for phacoemulsification for cataractous nucleus below III grade. CONCLUSIONS: For patients with axial myopia, the IOL implanted should create low myopia postoperatively. Larger optic size is better for fundus examination. Phacoemulsification can produce less astigmatism and damage, but the indication must be controlled strictly.

Adolescent↗
PubMed2000

[Analysis of refractive state after excimer laser photorefractive keratectomy in myopia].

OBJECTIVE: To evaluate refractive state after excimer laser photorefractive keratectomy (PRK) in patients with myopia. METHODS: 234 cases(391 eyes) followed up for two years were divided into two groups, group I: mild and moderate myopia(< or = -6.00 D), 228 eyes; group II: High myopia(> -6.00 D), 163 eyes. The refractive state of patients at three, six, twelve and twenty-four months postoperatively were monitored. RESULTS: At two years after photorefractive keratectomy (PRK), refractive regression (> -0.5 D), overcorrection(> 1.00 D), undercorrection(> 1.00 D), postoperative residual astigmatism postoperative astigmatism and hyperopia shift in group I were 1.7%, 4.4%, 5.7%, 12.8%, 7.4% and 7.5% respectively, while in high myopia group were 15.9%, 4.9%, 23.3%, 29.7%, 31.1% and 6.7% respectively. CONCLUSION: The results prove that photorefractive keratectomy is an effective, precise, stable and safe method for correction of mild and moderate myopia, but insufficient for high myopia.

Adolescent↗
PubMed2002

[Effect of TLT absorptive eyeglasses on progression of myopia in children].

The incidence of myopia is increasing worldwide. At the last VIIIth international conference on myopia held in June 2000 in Boston attention was aroused by the work of Quin et al. on the influence of noctural illumination in rooms where children slept on their subsequent development of myopia. Our working hypothesis presented in Hakone in 1996 presumes also a negative effect of light and heat which initiate the development of myopia but on eyes with an inborn disposition. We considered as a solution wearing spectacles with glass which allow to penetrate only visible light and absorb the other wavelengths. These glasses were supplied by Karel Kubĕna-TL Technologies. The authors followed up for four years two groups of children with progressive myopia. The progression of myopia during the first two years of the follow up was almost identical in the two groups: in the group with the absorption glasses 0.75 D/year and in the control group 0.77 D/year. After two years of wearing the absorption glasses the progression in the group with the absorption glasses was 0.34 D/year and in the control group 0.59 D/year.

Adolescent↗
PubMed2003

[Implantation of the Starr Surgical intraocular posterior chamber lenses for phakic eyes in medium and higher levels of myopia and hyperopia].

Implantation of an Intraocular Posterior-chamber Lens for a Phacik Eye from STAAR Surgical Co. in Medium and Higher Grades of Myopia and Hyperopia Implantation of an intraocular Collamer lens for a phacic eye produced by STAAR Surgical (ICL) co. is a modern method of correction of medium and high-grade refractive defects--myopia and hyperopia. The authors evaluate the results of implantation of ICL Staar Surgical in 20 eyes of 13 patients (1 man and 12 women). Their mean age was 31.36 +/- 9.21 years and the follow-up period 1-54 months (mean 28.8 months +/- 12.42). The group was divided into two sub-groups--hyperopia (8 eyes) and myopia (12 eyes). The mean value of refraction before surgery was 28 D +/- 2.03 and +0.25 Dcyl manifest (in cycloplegia +7.6 +/- 2.28 D) (from 3.75 D to 10.0 D) in the group of hyperopia and -14.25 D +/- 5.68 and -1.81 Dcyl (from -5.5 D to -25.0 D) in the myopic group. The required postoperative refraction was in 17 eyes emmetropia and in 3 eyes residual myopia up to -3.0 D with regard to incipient presbyopia. The authors evaluate the resultant best corrected visual acuity (BCVA), the resultant postoperative refraction, the incidence of postoperative complications and changed density of endothelial cells in the centre of the cornea in the course of time. In the group of hyperopia improvement of the BCVA as compared with the preoperative value occurred by one line in two eyes (25%), in 5 eyes (62.5%) BCVA remained unchanged. In one instance deterioration by one line occurred due to a diminution of endothelial cells in the centre of the cornea after surgery. In the group of myopia in 7 eyes (58.3%) improvement by 1 line occurred, in 2 eyes (16.7%) by 2 lines and in 3 cases (25%) BCVA remained unchanged. The mean value of postoperative refraction in the myopic group in required emmetropia (9 eyes) was -0.77 +/- 1.62 D and in required residual myopia (3 eyes) -1.5 +/- 1.32 D. The mean value of postoperative refraction in the group of hyperopia was +0.57 +/- 0.5 D for far sight and +1.28 +/- 0.58 D for near sight. The most frequent early postoperative complications included keratitis striata in 5, epithelopathy in 3 and residues of viscoelastic material behind the ICL in 3 eyes. As to late postoperative complications, in 2 eyes a change in endothelial cell density was involved, in 12 eyes the syndrome of pigment dispersal and in one eye late decentration of ICL occurred with subsequent anterior subcapsular cataract. The change in density of endothelial cells was most markedly expressed 3 months after surgery in the hyperopic group. The advantage of ICL implantation is rapid postoperative visual rehabilitation, reversibility of the operation, preserved accommodation and satisfactory stability of the postoperative refraction.

Adult↗
PubMed2003

[Corneal radius of curvature among people with myopia].

PURPOSE: To determine the behaviour of the radius of corneal curvature among people with myopia. MATERIAL AND METHODS: A total of 167 people with myopia (117 women and 50 men) aged 12 and 51, were examined. The average of age was 24. Routine ophthalmological examinations as well as keratometry were carried out. The data was analysed using the coefficient of rang Spearman's correlation and the coefficient of linear Pearson's correlation. RESULTS: A positive correlation was found between the length of an average of corneal curvature radius and myopia progress (P < 0.007). Any correlation between the age of the people with low, medium, and high myopia and the corneal curvature radius length was not observed. CONCLUSIONS: (1) In the course of myopia the average of corneal curvature radius is reduced. (2) The length of the average of corneal curvature radius does not depend on the age of people with myopia.

Adolescent↗
PubMed2004

Myopia progression among preschool Chinese children in Hong Kong.

INTRODUCTION: Myopia is the most common eye disorder especially in Asia. However, the information on myopic progression and ocular growth among preschool children, who undergo rapid changes, is limited. The aim of this study was to determine the prevalence, incidence of myopia and myopic progression among preschool children in Hong Kong. MATERIALS AND METHODS: A kindergarten was randomly chosen in Hong Kong, China. Preschool children aged 2 to 6 years attending the selected kindergarten were invited to participate. One hundred and eight children completed the 5-year cohort study. Refractive error and axial ocular dimensions were the main outcome measures. RESULTS: A total of 255 preschool children with a mean age of 4.96 (SD, 0.90) years were examined in the initial examination. Only 4.6% children had myopia of at least -0.50 D. The prevalence of myopia increased almost 10-fold to 43.5% after 5 years in the final examination. The annual incidence of myopia was 8.2%. The mean increase in axial length was 1.72 mm (SD, 0.80 mm) over the 5-year period (P < 0.001). The lens thickness decreased significantly from 3.80 mm (SD, 0.37 mm) to 3.74 mm (SD, 0.51 mm) whereas the vitreous chamber depth increased significantly from 15.01 mm (SD, 0.68 mm) to 16.42 mm (SD, 0.88 mm) (both P < 0.001). Children who were younger or were less hypermetropic at the initial examination was having greater myopic progression (P = 0.015, P < 0.001 respectively). CONCLUSION: This is the first prospective study to investigate the myopic progression and ocular growth among preschool children. Hong Kong has a high prevalence of myopia even in preschool children. They also experience a significant myopic shift and ocular growth. Further studies on the prevention of myopic development or progression should be targeted on this population.

Biometry↗
PubMedDate not supplied

[Prognostication of a complicated course of myopia in children].

The aim of the case study was to define the earliest criteria of the transformation of myopia into its aggravated form. Two related risk factors were isolated on the basis of a comprehensive examination of 135 children and teenagers with uncomplicated myopia of 0.5-16 d and with myopia complicated by different-type peripheral vitreochorioretinal dystrophies (PVCRD). They are primarily a reduced acoustic sclera density in the excavation zone and in the region of the posterior eye pole, diminished antioxidant reserve of the lachrymal fluid and heredity (presence of PVCRD in close relatives). Besides, a mild relationship was established between the eye fundus status in children and teenagers with myopia, on the one hand, and myopia progression rate, linear blood-flow velocity in the ciliary body, relative accommodation reserve and a value of the anterior-posterior eye axis, on the other hand. No reliable correlation was found between the eye fundus status and the below parameters: volumetric and linear blood flows in the ocular artery and in the posterior ciliary arteries, volumetric blood flow velocity in the ciliary body, intraocular pressure values, elastic elevation and rigidity factor. The most significant differences between the complicated and uncomplicated types of myopia in children were registered in its mild degree.

Adolescent↗
PubMed2004

Exclusion of lumican and fibromodulin as candidate genes in MYP3 linked high grade myopia.

PURPOSE: The proteoglycans lumican and fibromodulin regulate collagen fibril assembly and show expression in ocular tissues. A recent mouse knockout study implicates lumican and fibromodulin as functional candidate genes for high myopia. Lumican maps within the chromosome 12q21-q23 autosomal dominant high grade myopia-3 (MYP3) interval, and fibromodulin maps to chromosome 1q32. We screened individuals for lumican and fibromodulin sequence alterations from the original MYP3 family, and from a second high grade myopia pedigree that showed suggestive linkage to both the MYP3 interval and to chromosome 1q32. METHODS: A total of 10 affected (average spherical refractive error was -16.13 D) and 5 unaffected individuals from the 2 families were screened by direct DNA sequencing. Six primer pairs spanning intron-exon boundaries and coding regions were designed for the 3-exon 1804 base pair (bp) lumican gene. Two primer pairs for the 2-exon 2863 bp fibromodulin gene were designed. Polymerase chain reaction products were sequenced and analyzed using standard fluorescent methods. Sequences were quality scored and aligned for polymorphic analysis. RESULTS: Direct DNA sequencing of lumican amplicons yielded the expected sequence with no evidence of polymorphism or pathologic mutation. Sequencing of fibromodulin amplicons revealed 6 polymorphisms, 1 of which was novel. One polymorphism was a silent mutation, and five were in the 3' untranslated region. No polymorphism segregated with high myopia. CONCLUSIONS: Although null and double null Lum and Fmod mouse models have been developed for high myopia, our human cohort did not show affected status association with these genes. Sequencing of the human lumican and fibromodulin genes has excluded them as candidate genes for MYP3 associated high grade myopia.

Child↗
PubMed2005

Effect of pirenzepine ophthalmic solution on form-deprivation myopia in the guinea pigs.

BACKGROUND: Nonselective muscarinic receptor antagonist, atropine, was believed to inhibit myopic progression. The purpose of this study was to determine the efficacy, through topical administration, of the M1-selective muscarinic antagonist pirenzepine in preventing experimentally induced form-deprivation myopia in guinea pigs. METHODS: Fifty-three guinea pigs, which underwent monocular deprivation with their eyelids sutured, were divided into 6 groups. Three groups were treated with 1%, 2% or 4% pirenzepine ophthalmic solutions; the fourth group with atropine; the fifth with saline and the last group left untreated. Ocular refraction, in vivo biometric measurements and wet eye weight were collected before and after the experiment. All the eyes were finally enucleated for histopathological examination to evaluate the possible toxic effects on ocular structures. RESULTS: Animals untreated or treated with saline produced (-2.31+/-1.47) D and (-2.25+/-0.88) D of axial myopia respectively. Those treated with 1% pirenzepine ophthalmic solution produced relative myopia of (-1.63+/-0.48) D, and those under the treatment of 2% and 4% pirenzepine ophthalmic solution only developed a relative myopia of (-0.89+/-0.42) D and (-0.70+/-0.41) D (F=9.56, P<0.05). The significant reduction in myopia in 2% and 4% pirenzepine treated animals was caused by significantly less vitreous chamber elongation and axial elongation of the deprived eyes [2% group: (0.009+/-0.052) mm, 4% group: (0.006+/-0.078) mm] when compared with untreated, saline treated or 1% pirenzepine treated guinea pigs (0.057+/-0.056) mm, (0.064+/-0.053) mm and (0.033+/-0.035) mm, respectively]. Histological examinations revealed no obviously toxic effects on the eyes treated with pirenzepine. CONCLUSION: Topical administration of the M1-selective muscarinic antagonist, pirenzepine, can prevent induced form-deprivation myopia in guinea pigs by inhibiting axial elongation without obvious damage to ocular tissues.

Animals↗
PubMed2005

[Measurement of retinal thickness using optical coherence tomography in patients with myopia].

PURPOSE: Measurement of retinal thickness using optical coherence tomography in patients with myopia. MATERIAL AND METHODS: 39 patients, 23 girls and 16 boys, aged 14-18 years, were included in the study. Control group consisted of 18 patients. Each patient was subjected to routine ophthalmic investigations, which included the assessment of visual acuity for near and distant objects, autorefractometer, intraocular pressure measurement, biometry, static visual field. The macular retinal thickness was measured using the optical coherence tomograph (OCT). RESULTS: The mean macular retinal thickness in the eyes with low myopia was 162.0 microm, with medium myopia 158.5 micro, while in high myopia 125.0 microm. A statistical correlation was found between the retinal thickness in high myopia patients and in the control group. CONCLUSIONS: Optical coherence tomography can be employed to assess the retinal thickness and thus facilitate the observation of the evolution of alterations in myopia.

Adolescent↗
PubMed2005

[The effect of the type of astigmatism on the incidence of myopia].

PURPOSE: To determine whether and how with-the-rule, against-the-rule or oblique astigmatism influence the creation of myopia. MATERIAL AND METHODS: A total of 167 people with myopia (117 women and 50 men) of the age between 12 and 51, were examined. The overall average age was 24. Routine ophthalmological examinations as well as autorefractometry were carried out. The data was analysed using the coefficients of rang Spearman's correlation. RESULTS: It was found that with the rise of with-the-rule astigmatism myopia increases (P < 0.000001). Any correlation between the people with low, medium, and high myopia and the against-the-rule as well as oblique astigmatism was not observed. CONCLUSIONS: (1) With-the-rule astigmatism predisposes the creation of myopia. (2) Against-the-rule as well as oblique astigmatism has no influence on the creation of myopia.

Adolescent↗
PubMedDate not supplied

[Prevention of myopia in children].

Eye diseases rank third in the structure of morbidity among children aged 0 to 17 years. Acquired myopathy is the leading abnormality in the structure of morbidity, with diminished vision being in 28% of preschool children and in every two school graduates. Myopia is attended by the signs of systemic connective tissue dysplasia and impaired circulation due to autonomic dysfunction. Early diagnosis and correction of autonomic dysfunction is the basic line of the prevention and treatment of school myopia. Treatment of children can be organized in the medical room of a school. Along with general health-improving measures, physiotherapetic procedures, such as lens exercises, curative gymnastics, massage, and gentle manual therapy procedures should be used in the multimodality treatment of children with myopia. Autonomic tone can be regulated through the visual analyzer by pulse photostimulation on a spectral ophthalmologic apparatus (an up-to-date ACO-05 software model ("DEST", Cheboksary). Moreover, circulation improves, eye muscles become stronger, visual reflexes restore, and vision improves. A school oculist's room may be used as a new health-improving form in children with myopia. It should be set up in every school since the high efficiency of treatment for accommodation spasm is an important argument of the prevention of myopia, promotes a greater coverage of children with early myopia by means of therapeutic measures, as well as timely and contemporary prevention of progressive myopathy.

Child↗
PubMedDate not supplied

Prevalence and risk indicators of myopia among schoolchildren in Amman, Jordan.

We aimed to identify the prevalence and risk factors of myopia among secondary-school students in Amman. Thus 1777 (1081 males and 696 females) students aged 12-17 years old were recruited from 8 schools randomly selected from 8 different geographic locations in Amman. Data were collected by questionnaire, and self-reported myopia was checked against school medical records. The prevalence of myopia was 17.6%, with no significant difference between males and females after adjusting for other possible variables. Myopia was significantly associated with age, family history of myopia, computer use, and reading and writing outside school. Playing sports was inversely associated with myopia but there was no association with watching television.

Adolescent↗