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At least 145 records · Page 8Linked to original sources

PubMed2006

Novel locus for X linked recessive high myopia maps to Xq23-q25 but outside MYP1.

BACKGROUND: High myopia is a common genetic variation in most cases, affecting 1-2% of people, and is the fourth most common disorder causing blindness worldwide. Six autosomal dominant loci and one X-linked recessive locus have been reported, but no genes responsible for high myopia have been identified. OBJECTIVE: To report a Chinese family in which six males presented with high myopia consistent with an X linked recessive trait. RESULTS: Affected individuals shared three common features: high myopia, reduced visual acuity, and fundal changes of high myopia. Protan and deutan were observed in the family, but they did not co-segregate with the high myopia phenotype. X-chromosome-wide linkage analysis mapped the high myopia locus to a 25 cM (14.9 Mb) region on Xq23-q25 between DXS1210 and DXS8057, with maximum two point lod scores at theta = 0 of 2.75 and 2.29 for DXS1001 and DXS8059, respectively. CONCLUSIONS: This new myopia locus is outside the linked region of the first high myopia locus (MYP1). Refinement of the linkage region with additional families and screening candidate genes for mutation may lead to the identification of the defect gene.

Adult↗

PubMed2003

A randomized clinical trial of progressive addition lenses versus single vision lenses on the progression of myopia in children.

PURPOSE: The purpose of the Correction of Myopia Evaluation Trial (COMET) was to evaluate the effect of progressive addition lenses (PALs) compared with single vision lenses (SVLs) on the progression of juvenile-onset myopia. METHODS: COMET enrolled 469 children (ages 6-11 years) with myopia between -1.25 and -4.50 D spherical equivalent. The children were recruited at four colleges of optometry in the United States and were ethnically diverse. They were randomly assigned to receive either PALs with a +2.00 addition (n = 235) or SVLs (n = 234), the conventional spectacle treatment for myopia, and were followed for 3 years. The primary outcome measure was progression of myopia, as determined by autorefraction after cycloplegia with 2 drops of 1% tropicamide at each annual visit. The secondary outcome measure was change in axial length of the eyes, as assessed by A-scan ultrasonography. Child-based analyses (i.e., the mean of the two eyes) were used. Results were adjusted for important covariates, by using multiple linear regression. RESULTS: Of the 469 children (mean age at baseline, 9.3 +/- 1.3 years), 462 (98.5%) completed the 3-year visit. Mean (+/-SE) 3-year increases in myopia (spherical equivalent) were -1.28 +/- 0.06 D in the PAL group and -1.48 +/- 0.06 D in the SVL group. The 3-year difference in progression of 0.20 +/- 0.08 D between the two groups was statistically significant (P = 0.004). The treatment effect was observed primarily in the first year. The number of prescription changes differed significantly by treatment group only in the first year. At 6 months, 17% of the PAL group versus 30% of the SVL group needed a prescription change (P = 0.0007), and, at 1 year, 43% of the PAL group versus 59% of the SVL group required a prescription change (P = 0.002). Interaction analyses identified a significantly larger treatment effect of PALs in children with lower versus higher baseline accommodative response at near (P = 0.03) and with lower versus higher baseline myopia (P = 0.04). Mean (+/- SE) increases in the axial length of eyes of children in the PAL and SVL groups, respectively, were: 0.64 +/- 0.02 mm and 0.75 +/- 0.02 mm, with a statistically significant 3-year mean difference of 0.11 +/- 0.03 mm (P = 0.0002). Mean changes in axial length correlated with those in refractive error (r = 0.86 for PAL and 0.89 for SVL). CONCLUSIONS: Use of PALs compared with SVLs slowed the progression of myopia in COMET children by a small, statistically significant amount only during the first year. The size of the treatment effect remained similar and significant for the next 2 years. The results provide some support for the COMET rationale-that is, a role for defocus in progression of myopia. The small magnitude of the effect does not warrant a change in clinical practice.

Child↗

PubMed2006

Accommodative lag before and after the onset of myopia.

PURPOSE: To evaluate accommodative lag before, during the year of, and after the onset of myopia in children who became myopic, compared with emmetropes. METHODS: The subjects were 568 children who became myopic (at least -0.75 D in each meridian) and 539 children who were emmetropic (between -0.25 D and +1.00 D in each meridian at all visits) participating between 1995 and 2003 in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study. Accommodative lag was measured annually with either a Canon R-1 (Canon USA., Lake Success, NY; no longer manufactured) or a Grand Seiko WR 5100-K (Grand Seiko Co., Hiroshima, Japan) autorefractor. Subjects wore their habitual refractive corrections while viewing a letter target accommodative stimulus of 4 D (either in a Badal system or at 25 cm from the subject, designated Badal and near, respectively) or of 2 D (Badal only). Refractive error was measured with the same autorefractor in subjects under cycloplegia. Accommodative lag in children who became myopic was compared to age-, gender-, and ethnicity-matched model estimates of emmetropic values for each annual visit from 5 years before, through 5 years after, the onset of myopia. RESULTS: In the sample as a whole, accommodative lag was not significantly different in children who became myopic compared with model estimates in emmetropes in any year before onset of myopia for either the 4-D or 2-D Badal stimulus. For the 4-D near target, there was only a greater amount of accommodative lag in children who became myopic compared with emmetropes 4 years before onset (difference, 0.22 D; P = 0.0002). Accommodative lag was not significantly elevated during the year of onset of myopia in any of the three measurement conditions (P < 0.82 for all three). A consistently higher lag was seen in children after the onset of their myopia (range, 0.13-0.56 D; P < 0.004 for all comparisons). These patterns were generally followed by each ethnic group, with Asian children typically showing the most, African-American and white children showing the least, and Hispanic children having intermediate accommodative lag. CONCLUSIONS: Substantive and consistent elevations in accommodative lag relative to model estimates of lag in emmetropes did not occur in children who became myopic before the onset of myopia or during the year of onset. Increased accommodative lag occurred in children after the onset of myopia. Elevated accommodative lag is unlikely to be a useful predictive factor for the onset of myopia. Increased hyperopic defocus from accommodative lag may be a consequence rather than a cause of myopia.

Accommodation, Ocular↗

PubMedDate not supplied

Influence of patient age on photorefractive keratectomy for myopia.

BACKGROUND: To determine whether the outcomes of photorefractive keratectomy (PRK) for myopia are age-dependent. METHODS: The influence of age on PRK outcomes was analyzed for one eye of each of 72 patients divided into two groups: 39 patients (18 to 26 years) and 33 patients (35 to 54 years). The influence of the amount of preoperative myopia (low myopia less than -4.00 diopters (D); moderate to high myopia -4.00 or more D) was also evaluated. All patients were followed for at least 1 year, and all underwent cycloplegic refractions. RESULTS: One year after PRK, the average refraction was -0.15 D in the younger group and +0.38 D in the older group. The achieved refraction was higher than the attempted by +1.00 D or more only in eyes with moderate to high myopia (-4.00 to -10.00 D); 11.54% (3 eyes) of the younger group and in 34.78% (8 eyes) of the older group. CONCLUSIONS: After PRK for myopia, patients between the ages of 35 and 54, with moderate to high myopia, obtained more refractive change with the same intended dioptric correction compared to younger patients with moderate to high myopia. Attempted correction should be adjusted according to age and amount of myopia.

Accommodation, Ocular↗

PubMed2005

[Prevalence rate and factors of myopia in preschool children].

PURPOSE: This study was aimed at providing basic data for developing a nursing intervention program which enables systematic and correct visual acuity care by discovering out visual acuity conditions, prevalence rate of myopia, and the factors related to myopia with Preschool children. METHOD: The subjects of this study consisted of 519 children between 3 and 6 years of age from 12 kindergartens in Seoul which were selected through multiple cluster sampling. Myopia was defined as the spherical equivalent (SE) of more than -0.5 diopters (D) in the right eye. The data was analyzed by t-test, chi(2)-test, ANOVA, and logistic regression by using the SAS program. RESULT: The prevalence rate of myopia was 8.7%. the odds ratio of child myopia when one parent had myopia was 2.2 times higher than when neither parent had myopia. The odds ratio of child myopia when reading more than three books per week was 0.27 times higher than reading less than three books. CONCLUSION: Myopia should be continuously and intensively managed from the age of 3.

Child↗

PubMed1999

Ocular predictors of the onset of juvenile myopia.

PURPOSE: The purpose of this study was to identify reliable predictors of the onset of juvenile myopia. METHODS: The data from 554 children enrolled in the Orinda Longitudinal Study of Myopia (OLSM) as nonmyopes with baseline data from the third grade were evaluated to develop a predictive profile for later onset of juvenile myopia. Myopia was defined as at least -0.75 D of myopia in the vertical and horizontal meridians of the right eye as measured by cycloplegic autorefraction (n = 45 children). Chosen predictors were refractive error and the ocular components: corneal power, Gullstrand crystalline lens power, and axial length. Sensitivity and specificity were calculated. Receiver operating characteristic (ROC) curves were generated to evaluate and compare these predictors singly and combined. RESULTS: Refractive error, axial length, Gullstrand lens and pod corneal power were all significant predictive factors for the onset of juvenile myopia. The best single predictor of future myopia onset in the right eye was the right eye's cycloplegic autorefraction spherical refractive error value (mean sphere across 10 readings) at baseline. For a cut point of less than +0.75 D hyperopia in the third grade, sensitivity was 86.7% and specificity was 73.3%. The area under the ROC curve for this mean sphere was 0.880. Producing a logistic model combining mean sphere, corneal power, Gullstrand lens power, and axial length results in a slight improvement in predictive ability (area under the ROC curve = 0.893). CONCLUSIONS: Onset of juvenile myopia can be predicted with moderate accuracy using the mean cycloplegic, spherical refractive error in the third grade. Measurement of other ocular components at this age improves predictive ability, albeit incrementally. Further improvements in the prediction of myopia onset will require the use of longitudinal data in addition to one-time measurement of refractive error and the ocular components.

Adolescent↗

PubMed2000

[Evaluation of selected parameters of collagen metabolism in patients with myopia].

INTRODUCTION: Myopia is a common condition of vision deprivation characterized by the excessive lengthening of the eye axis. There are hypotheses that the elongation of the eye is connected with the connective tissue disorder in which the scleral collagens are inappropriately remodelled. The most common type of collagen and the first to be discovered is type I and it is the dominating one in cornea and sclera. Type III is always found in coexistence with type I. AIMS: The aim of the study was to evaluate the serum concentration of carboxyterminal propeptyde of procollagen type I (P I CP), aminoterminal propeptyde of procollagen type III (P III NP) (markers of collagen synthesis) and carboxyterminal telopeptyde of collagen type I (I CTP) (marker of collagen disintegration) as markers of the connective tissue metabolism in patients with myopia. MATERIAL AND METHODS: Serum concentration of P I CP, P III NP and I CTP were studied in 25 (15 female and 10 male) patients with myopia and in 15 emmetropic subjects using the RIA method (Orion Diagnostica). RESULTS: The serum concentration of P I CP and P III NP increased significantly in patients with myopia when compared with the control group. There was no significant difference in the concentration of both of them among patients with various degrees of myopia, although the concentration of P I CP and P III NP increased with the increase of myopia. The was no statistical difference in the concentration of I CTP in low and medium myopia but we found increased concentration of I CTP in high myopia comparing with control group. CONCLUSION: The mechanical properties as well as the increased remodelling of the collagen could be some of the factors involved in myopia pathogenesis. Changes in the collagen metabolism concern not only the eye tissue, but probably also disorders of the systemic connective tissue turnover.

Adult↗

PubMed2001

Posterior scleroplasty in children with severe myopia.

PURPOSE: To assess the influence of scleral reinforcement on the evolution of severe myopia in children. MATERIAL AND METHODS: Scleral reinforcement after Thompson was performed on 251 eyes of 154 children with high myopia from 2 to 18 years of age. The main indication criteria for surgery during the period 1992-2000 included: severe myopia more than -7 Diopters and the increase in refraction more than -1 D(per year. Zenoderm (porcin skin) was the main alloplastic material used during surgery. No serious complications were observed. The following main indicators of myopia advancement were investigated on a long-term basis and evaluated: axial length, refraction, visual acuity, fundus findings and perimetry. RESULTS: The positive influence of surgery on myopia advancement was observed in 100% of patients. In about 53% of operated eyes, myopia was absolutely stopped, and in about 47% of operated eyes, its advancement was considerably reduced. During 10 years of postsurgical check-up, stabilisation of myopia was achieved, the following in individual indicators: axial length--53.8% of eyes, refraction--52.9% of eyes, visual acuity--85% of eyes, fundus findings--58.6% of eyes, perimetry--59.1% of eyes. The advancement of myopia in other 47% of patients has been decreased from 1.1 D/per year before surgery to 0.1 D till 10 years after surgery. CONCLUSION: Scleral reinforcement is an effective and safe surgery that can stabilise the progression of severe myopia in children. (Tab. 6, Fig. 7, Ref. 12.).

Adolescent↗

PubMed2004

Evidence for an "epidemic" of myopia.

INTRODUCTION: It has been widely suggested that the prevalence of myopia is growing worldwide, and that the increases observed in East Asia, in particular, are sufficiently severe as to warrant the term "epidemic". Data in favour of a cohort effect in myopia prevalence are reviewed, with attention to significant shortcomings in the quality of available evidence. Additional factors contributing to myopia prevalence, including near work, genetics and socioeconomic status, are detailed. MATERIALS AND METHODS: Medline search of articles regarding myopia prevalence, trends and mechanisms. RESULTS: Age-related changes in myopia prevalence (increase during childhood, and regression in the fifth and sixth decades) are discussed as an alternative explanation for cross-sectional patterns in myopia prevalence. There have only been a handful of studies that have examined the relative contribution of longitudinal changes in refraction over life and birth cohort differences on age-specific myopia prevalence as measured in cross-sectional studies. Available data suggest that both longitudinal changes and cohort effects may be present, and that their relative contribution may differ in different racial groups. CONCLUSIONS: In view of the relatively weak evidence in favour of a large cohort effect for myopia in East Asia, and the even greater lack of evidence for increased prevalence of secondary ocular pathology, there appears to be inadequate support for large-scale interventions to prevent or delay myopia at the present time.

Asia, Eastern↗

PubMed2006

Methodologies for interventional myopia studies.

Myopia studies are notoriously difficult to carry out. Past studies on intervention in myopia progression have given conflicting results. Beside inaccurate and inadequate measurements, the most important cause for this is the very variable nature of myopia, which makes it difficult to achieve baseline comparability between the control and the study group. Although there were inclusion criteria in these studies, for age, sex, race, degree of myopia and stigmatism, the most important variate-- the rate of myopia progression-- was not included. Randomisation can achieve baseline comparability of the myopia progression rate, provided the sample sizes are large enough. Unfortunately, past studies have been limited to 100 to 200 children only. Studies on twins are more reliable than random groups because myopia progression rates are more likely to be the same in a pair of twins. Studies on the same subject, comparing the right eye and the left eye would be even better, but this method is practicable for some studies only (e.g., we cannot have a spectacle lens for one eye and a contact lens on the fellow eye). There is another method of doing an interventional study on myopia. Because myopia progression is linear in its early stage until the early teenage years, it is possible to observe what happens to the linear progression upon intervention. In this way, we avoid the problem of trying to compare "apples with apples" but use the "same apple" instead.

Contact Lenses↗

PubMed2006

[Influence of diameter of optical zone ablation on LASIK-induced higher order optical aberrations in myopia].

OBJECTIVE: To analyze the effects of optical zone ablation diameter on LASIK-induced higher order optical aberrations in myopia. METHODS: Four hundred and sixty-one eyes of 236 patients treated with LASIK for myopia were divided into high, moderate and low myopia group according to preoperative spherical equivalent diopter. In each group, eyes were divided into four subgroups according to optic zone ablation diameter. Before and after surgery 6 months, monochromatic wavefront aberrations of each eye were objectively measured using WASCA Analyzer Aberrometer. F test and q test were used to analyze the difference of total high order, horizontal coma, vertical coma, and spherical aberrations among four subgroups in each group at 4, 5, and 6 mm pupil size. RESULTS: Before surgery no significant difference of higher order aberrations among four subgroups was found. After surgery, there was significant difference of total high order, and spherical aberrations among four subgroups. Total high order, and spherical aberrations in larger optical zone ablation diameter subgroup were significantly lower than that in smaller one. The difference was significant at 4, 5, and 6 mm pupil size in high myopia group, and 6 mm pupil size in low myopia group. At 6 mm pupil size, the difference was significant between each subgroup in high myopia group and subgroup I and subgroup IV in low myopia group. There was no significant difference of horizontal coma, and vertical coma aberrations among four subgroups. CONCLUSIONS: Optical zone ablation diameter has influence on LASIK-induced higher order optical aberrations. Larger optical zone can decrease total higher order and spherical aberrations after LASIK. The effects are more significant in high myopia group than in low myopia group.

Adolescent↗

PubMed1997

A longitudinal investigation of adult-onset and adult-progression of myopia in an occupational group. Refractive and biometric findings.

PURPOSE: To investigate the refractive and biometric changes associated with adult-onset and adult-progression of myopia in an occupational group. METHODS: The sample population consisted of 251 clinical microscopists aged 21 to 63 years. Subjects had their refraction and ocular dimensions measured on four occasions during a 2-year period, and a total of 166 subjects (332 eyes) completed the longitudinal aspect of the study. Refraction was measured objectively with a Canon R-1 autorefractor and subjectively by an optometrist using standard procedures. Corneal curvature and axial ocular dimensions were measured with a keratometer and A-scan ultrasonography, respectively. RESULTS: Of eyes emmetropic at the start of the study, a total of 39% underwent a myopic change in refraction greater than 0.37 diopter (D), with a mean change of -0.58 +/- 0.04 D (mean +/- standard error of the mean; n = 37). This was associated with an elongation of the vitreous chamber of 0.26 +/- 0.05 mm (P < 0.01). Eyes emmetropic at the start of the study that did not undergo a refractive change > 0.37 D (n = 58) during the 2-year study period had a mean change in refraction of 0.02 +/- 0.03 D (P = 0.69) associated with a change in vitreous chamber depth of 0.05 +/- 0.02 mm. Changes in corneal curvature, anterior chamber depth, or lens thickness between the initially emmetropic groups were not significant. The median age of onset of myopia in initially emmetropic eyes was 26.3 years. Of eyes that were myopic at the start of the study, 48% progressed further into myopia by 0.37 D or more during the 2-year period. The mean increase in myopia for the "myopia progressor" group was 0.77 +/- 0.03 D (n = 108 eyes) compared to -0.01 +/- 0.02 D (n = 115 eyes; P = 0.49) for myopes who did not undergo a refractive change > 0.37 D during the study period. The only significant difference in ocular component dimension changes during the study period for these two initially myopic groups was elongation of the vitreous chamber depth (0.24 +/- 0.04 mm versus 0.03 +/- 0.03 mm, P < 0.01). The average age of the myopes who progressed further into myopia during the study was 29.3 years. Axial length-corneal radius ratio at the start of the study was not significantly different between initially emmetropic eyes in which adult onset myopia developed or emmetropic eyes that remained refractively stable. The incidence of adult myopia development during a 2-year period in this occupational group was 45%. CONCLUSIONS: The structural cause of adult-onset and adult-progression of myopia is vitreous chamber elongation.

Adult↗

PubMedDate not supplied

Refractive errors and factors associated with myopia in an adult Japanese population.

PURPOSE: To investigate the refractive status and factors associated with myopia by a population-based survey of Japanese adults. METHODS: A total of 2168 subjects aged 40 to 79 years, randomly selected from a local community, were assessed in a cross-sectional study. The spherical equivalent of the refractive error was calculated and used in a multiple logistic regression analysis to evaluate the relationships between myopia and possible related factors. RESULTS: The mean (+/- SD) of the spherical equivalent was -0.70 +/- 1.40 diopters (D) in men, and -0.50 +/- 1.44 D in women. Based on +/- 0.5 D cutoff points, the prevalence of myopia, emmetropia, and hypermetropia were 45.7%, 40.8%, and 13.5% in men, and 38.3%, 43.1%, and 18.6% in women, respectively. A 10-year increase in age was associated with reduced risk of myopia [men: odds ratio (OR) = 0.53, 95% confidence interval (CI): 0.44-0.62; women: OR = 0.65, 95% CI: 0.54-0.78]. In men, myopia was significantly associated with higher education (high school: OR = 1.6, 95% CI: 1.1-2.3; college: OR = 2.0, 95% CI: 1.3-3.1) and management occupations (OR = 1.6, 95% CI: 1.0-2.4). For women, high income (OR = 1.5, 95% CI: 1.1-2.2), and clerical (OR = 1.5, 95% CI: 1.0-2.4) and sales/service occupations (OR = 1.7, 95% CI: 1.1-2.6) were also associated with myopia. CONCLUSIONS: The prevalence of myopia in a Japanese population was similar to that in other Asian surveys but higher than in black or white populations. Our study confirmed a higher prevalence of myopia among younger vs. older populations, and a significant association with education levels and socioeconomic factors.

Adult↗

PubMed1998

A model of the contribution of oculomotor and optical factors to emmetropization and myopia.

The purpose of this work was to investigate quantitatively the interactions between accommodation, vergence and a mechanism of emmetropization driven by optical blur within the retinal image with a view to developing a model that provides an explanation of both normal emmetropization and near-work associated myopia. The simulations of the change in the refractive state of the eye over time that derive from this model indicate that optical regulation of eye growth can result in emmetropization, i.e. a progressive reduction in refractive errors over time leading towards emmetropia. This occurs when viewing conditions involve a preponderance of distance work. With increasing near work, the model predicts that the refraction of the eyes will converge towards myopia. In keeping with the previously reported associations of myopia with esophoria, poor accommodation function and high AC/A ratios, these conditions increase the amount of myopia produced under intensive near viewing conditions but do not lead to myopia during mainly distance viewing. This model provides quantitative validation of the hypothesis that the epidemiological association between myopia and increased nearwork may be caused by a disturbance of normal emmetropization by steady state errors of accommodation. The same model can explain normal emmetropization, increasing myopia with increasing nearwork demands and the currently recognised oculomotor associations that have been reported to precede the development of myopia.

Accommodation, Ocular↗

PubMed1993

Prevalence of posterior vitreous detachment in high myopia.

BACKGROUND: Posterior vitreous detachment is known to develop early in high myopia. However, the prevalence of posterior vitreous detachment in relation to patient age and degree of myopia has not been studied by modern vitreous examination methods. METHODS: The vitreous conditions of 224 eyes with high myopia (> -6 diopters [D]) were examined biomicroscopically with a +90-D present lens and a Goldmann three-mirror contact lens. The vitreous conditions of 220 eyes with emmetropia (between -1 and +1 D) also were studied and served as controls. RESULTS: In high myopia, no patients 29 years of age or younger had posterior vitreous detachment. Thereafter, the prevalence of posterior vitreous detachment increased with age (i.e., 23%, 29%, 44%, and 72% in the fourth through seventh decades, respectively, and 100% of patients 70 years or older). Moreover, posterior vitreous detachment developed earlier in severe high myopia (> -10 D) than in moderate high myopia (> -6 to -10 D). In emmetropia, no patients 39 years of age or younger had posterior vitreous detachment, and its prevalence also increased with age (i.e., 8%, 23%, 44%, 74%, and 86% in the fifth through ninth decades, respectively). CONCLUSION: In high myopia, posterior vitreous detachment develops increasingly with age and degree of myopia. Although the sample size in each age group was small, the results suggested that posterior vitreous detachment may develop nearly 10 years earlier in highly myopic than in emmetropic eyes.

Adolescent↗

PubMed1997

Predictability of excimer laser treatment of myopia and astigmatism by the VISX Twenty-Twenty. Melbourne Excimer Laser Group.

BACKGROUND: To determine the predictability of excimer laser photorefractive keratectomy (PRK) to correct myopia, astigmatism, or both between -1.00 and -19.00 diopters (D). SETTING: Royal Victorian Eye and Ear Hospital, East Melbourne, Australia. METHODS: This study comprised 1218 consecutive eyes treated with a VISX Twenty-Twenty excimer laser and followed prospectively for 12 months. Low myopia was treated with one ablation zone (6.0 mm), high myopia with two ablation zones (5.0 and 6.0 mm), and extreme myopia with three ablation zones (4.5, 5.0, and 6.0 mm). Maximum spherical treatment was 15.00 D at the corneal plane. Data were analyzed to determine the predictability of the postoperative outcomes by preoperative refraction. RESULTS: Nine hundred eighty eyes (80.5%) were available for the 12 month follow-up. The predictability of refraction and uncorrected and best corrected visual acuities progressively decreased with increasing myopia, although a comparable percentage of spherical correction was achieved at each diopter of myopia. The likelihood of losing lines of best corrected visual acuity and corneal haze increased with increasing myopia. CONCLUSION: These data can be used to counsel patients of likely outcomes of excimer laser PRK to correct myopia.

Adult↗

PubMed2001

Associations of high myopia in childhood.

PURPOSE: High myopia in early childhood is a recognised association of ocular and systemic disease. The aim of this study was to describe the types, pattern and frequency of these associations. METHODS: All children presenting to two ophthalmology units over 3 years who were found to have high myopia were recruited. High myopia was defined as one or both eyes demonstrating 6 dioptres spherical equivalent or more of myopic refractive error on retinoscopy. We limited the age to less than 10 years old. A retrospective case review was undertaken of the 112 consecutive children who fulfilled the criteria above. The demographic data, source and indication for referral were recorded along with the ocular and systemic findings and diagnosis. RESULTS: Only 9 (8%) of the children had 'simple high myopia' with no associated ocular or systemic associations. In 54% there was an underlying systemic association with or without further ocular problems (e.g. developmental delay, prematurity, Marfan, Stickler, Noonan, Down syndrome) and in the remaining 38% there were further ocular problems associated with the high myopia (e.g. lens subluxation, coloboma, retinal dystrophy, anisometropic amblyopia). A family history of high myopia did not preclude associated abnormality: in 4 cases the diagnosis of a systemic condition in the child led to the identification of the disease in at least one myopic relative. Asian (p < 0.001) and male (p < 0.05) patients were overrepresented in the series. CONCLUSION: High myopia is strongly associated with systemic and ocular problems; it may be the reason for the child's initial medical referral and an important clue to an underlying systemic or ocular condition. Referrals infrequently originated from community optometrists despite prior attendance. We suggest that all children under 10 years of age with high myopia are referred to a paediatric ophthalmology clinic for review and we propose a structured clinical evaluation in the hospital eye clinic.

Child↗

PubMed2005

Relation between the axial length and lenticular progressive myopia.

PURPOSE: To investigate the possible risk factors associated with lenticular progressive myopia and to compare the differences between patients with lenticular progressive myopias and senile cataracts. METHODS: We retrospectively reviewed cases that had been diagnosed as lenticular progressive myopia with a discrete nuclear sclerotic cataract and progressive myopic changes in one hospital from January 1998 to February 2003. A total of 47 eyes of 35 patients were enrolled in this study. In all, 32 eyes of 29 cases of common senile cataract receiving cataract extraction surgery during the study period were randomly chosen (every four cases in time sequence within a 2-month period by two ophthalmologists' clinic in 2002) as the control group. We compared the preoperative refraction status, keratometry (K-values) and axial lengths between these two groups. The possible ocular or systemic associating diseases were also investigated in the study group. RESULTS: In the lenticular progressive myopia group, the mean age at surgery (52.9+/-9.2 years) is younger than that in the senile cataract group (68.1+/-7.3 years). The mean axial length in the study group (25.68+/-1.93 mm) is statistically significant longer than that in the control group (22.97+/-0.83 mm) (P<0.0001). Besides, patients with lenticular progressive myopia had significantly lower mean K-values (43.25+/-1.42 diopters) than patients with senile cataracts (44.25+/-1.28 diopters) (P<0.01). There were no other ocular or systemic diseases closely associated with lenticular progressive myopia. CONCLUSIONS: Patients with nuclear cataract combined with lenticular progressive myopia have longer axial length than patients with senile cataract. The longer axial length may be one of the important risk factors predisposing to lenticular progressive myopia.

Adult↗