Home About us Contact
|
Home About us Contact | ||
|
|
||
Myopic Subjects (myopic + subject)
Selected AbstractsA novel genetic variant of BMP2K contributes to high myopiaJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 6 2009Hsin-Ping Liu Abstract Loss of eye growth regulation may cause myopia, because modulation of optic globe size is essential for the generation of normal optic power. Evidence has implied variations of BMP2 gene expression mediate ocular development and retinal tissue remodeling. Given BMP2 as a potential regulator involved in myopia development, we investigate whether gene BMP2-inducible kinase (BMP2K, BIKe), whose expression is up-regulated during BMP2-induced osteoblast differentiation, contributes to susceptibility of high myopia. Participants grouped into high myopia had a spherical equivalent greater than ,6.00 D, compared with a control group of spherical equivalent less than ,0.5 D. Genotyping of polymorphisms 1379 G/A (rs2288255) and 3171 C/G (rs12507099), corresponding with 405 Gly/Ser and 1002 Thr/Ser variation in the BMP2K gene were determined by PCR-restriction fragment length polymorphism and associative study performed by comparing high myopic subjects and healthy controls. The frequency of A allele in the BMP2K gene 1379 G/A polymorphism showed a significant difference between cases and controls (P<0.001, OR=2.99, 95% CI=1.62,5.54) and subjects with either AA or AG genotype show higher risk than GG genotype (P<0.001, OR=3.07, 95% CI=1.59,5.92), while 3171 C/G polymorphism was not significant from this survey. These data suggest that BMP2K gene 1379 G/A variant is strongly correlated with high myopia and may contribute to a genetic risk factor for high degrees of myopic pathogenesis. J. Clin. Lab. Anal. 23:362,367, 2009. © 2009 Wiley-Liss, Inc. [source] A pilot study on the differences in wavefront aberrations between two ethnic groups of young generally myopic subjectsOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2008Alejandro Cerviño Abstract A comparative population-based cross-sectional study design was used to examine the prevalence of wavefront patterns in two different ethnic groups, and the relationship of these patterns with ocular biometrics and gender. The Shin,Nippon SRW5000 open field autorefractor, the Wavefront Analysis Supported Customized Ablation (WASCA) wavefront analyser and the IOLMaster were used to determine wavefront aberrations, mean spherical equivalent (SE) refractive error and axial length (AL). Seventy-four eyes from 74 young healthy subjects (44 British Asians, 30 Caucasians; 36 men, 38 women; mean age 22.51 ± 3.89 years) with mean SE averaging ,1.90 ± 2.76 D (range ,10.88 to +2.19 D) were examined. Relationships between ethnicity, gender, AL and SE, against the wavefront high-order root mean square, and aberration components up to the fifth order, were assessed by using multiple regression and correlation analysis. AL on its own accounted for 4.7% of the variance in trefoil component (F1,72 = 4.602; p = 0.035), 13.7% of coma component (F1,72 = 12.536; p = 0.001), 6.1% of trefoil component (F1,72 = 5.705; p = 0.020) and 9.8% of coefficient (F1,72 = 8.908; p = 0.004). A significant model emerged (F2,71 = 6.164; p = 0.003) for ethnicity and axial length, accounting for 12.4% of variance in primary spherical aberration with ethnicity accounting for 8.4% of that variance. For Caucasian subjects, a significant correlation was found between axial length and (Pearson's correlation coefficient ,0.500; p = 0.005) and (Pearson's correlation coefficient ,0.423; p = 0.020). For British Asian subjects, AL was only correlated with coefficient (Pearson's correlation coefficient ,0.358; p = 0.017). Ethnicity is a factor to be considered in the variability of wavefront aberration, particularly spherical aberration. Relationship between AL and wavefront aberrations seems to vary between ethnicities. If higher order aberrations play a role in the emmetropization process, this may be different for different populations. [source] Refractive group differences in accommodation microfluctuations with changing accommodation stimulusOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2006Mhairi Day Abstract Purpose:, Microfluctuations of accommodation are known to increase in magnitude with increasing accommodation stimulus. Reduced sensitivity to blur in myopic subjects could also lead to increases in the magnitude of the microfluctuations. The aim of this study is to examine the effect of variations in accommodation stimulus upon the microfluctuations in different refractive groups. Methods:, Thirty-six subjects were divided into three groups depending upon their refractive error and age of onset of their myopia; 12 emmetropes (EMMs), 12 early onset myopes (EOMs) and 12 late-onset myopes (LOMs). Steady-state accommodation responses were recorded continuously for 2 min using the Shin-Nippon SRW-5000 autorefractor at a sampling rate of 52 Hz while viewing targets at accommodation stimuli levels of 0, 1, 2, 3 and 4 D in a Badal (+5 D) optical system. Results:, The EMMs and EOMs showed systematic increases in the root mean square (r.m.s.) value of the microfluctuations with increasing accommodation stimulus. In contrast, no systematic variation with accommodation stimulus was found for the LOMs. Power spectrum analysis demonstrated that increases in the size of the microfluctuations were mediated by increases in the power of the low frequency components of the accommodation response. Conclusions:, The magnitude of the microfluctuations in the EMMs and EOMs may be influenced primarily by accommodation response-induced zonular relaxation effects or to changes in the physical properties of the accommodation plant with increasing accommodation response. The LOMs may have an increased baseline neural blur threshold, which appears to modulate the magnitude of the accommodative microfluctuations for low accommodation levels. At higher accommodation demands, the changes in the physical properties of the accommodation plant or the zonular relaxation effects appear to exceed the blur threshold, and the known association between microfluctuations and accommodation stimulus level is restored. [source] Comparison of two partial coherence interferometers for corneal pachymetry in high myopia and after LASIKACTA OPHTHALMOLOGICA, Issue 4 2009Anders Ivarsen Abstract. Purpose:, We aimed to compare the Haag-Streit optical low-coherence reflectometry (OLCR) pachymeter and the Zeiss Anterior Chamber Master (ACMaster) for measuring central corneal thickness (CCT) in high myopes and after laser in situ keratomileusis (LASIK) for myopia. Methods:, Central corneal thickness was measured in 55 eyes of 30 myopic subjects (spherical equivalent refraction of , 5.25 D to , 10.75 D, maximal astigmatism of , 2 D), and in 37 eyes of 21 patients 3 months after LASIK for myopia (preoperative spherical equivalent refraction of , 6.0 D to , 10.75 D, maximal astigmatism of , 2 D). All measurements were performed with the Haag-Streit OLCR pachymeter and the Zeiss ACMaster, using group refractive indices of 1.376 and 1.3851, respectively. Thickness measurements were compared using paired t -tests, Pearson's correlation, linear regression and Bland,Altman plots. Results:, In myopic subjects, CCT measured 531 ± 28 ,m and 533 ± 27 ,m with the OLCR pachymeter and the ACMaster, respectively (p < 0.01); all measurements correlated closely (r = 0.99, p < 0.01). In LASIK-treated eyes, CCT measured 472 ± 24 ,m using the OLCR pachymeter and 475 ± 23 ,m using the ACMaster (p < 0.01), again with close correlation between the two instruments (r = 0.99, p < 0.01). Conclusions:, Measurements of CCT in high myopes and after myopic LASIK were very similar with the Haag-Streit OLCR pachymeter and the Zeiss ACMaster. Using the current group refractive indices, the observed difference between the two instruments of < 3 ,m is of little clinical importance. Thus, it would seem safe to use the OLCR pachymeter and the ACMaster interchangeably for CCT measurements in myopia as well as after myopic LASIK. [source] Family history of myopia is not related to the final amount of refractive error in low and moderate myopiaCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2005Rafael Iribarren MD Abstract Background:, Previous research has found an association between family history and presence of myopia. It is possible that family history also could be related to the final amount of refractive error developed. If that were true, then family history of myopia could have predictive value for the amount of refractive error a child or young adult would develop after first lens prescription. Methods:, Consecutive myopic adult outpatients were enrolled during the year 2003. They received a refractive examination and a questionnaire concerning age of onset of lens use, academic achievement, and parental history of myopia. Results:, In the group of 271 mild and moderate myopes (myopia lower than ,6 D) there were 157 subjects with at least one myopic parent and 114 subjects without family history. The presence or absence of a family history of myopia was not associated with either the final myopic refractive error (,3.2 ± 1.5 D and ,2.9 ± 1.3 D, respectively, P = 0.08) or the age of onset of lens use (17.0 ± 6.2 years vs 18.1 ± 6.7 years, respectively, P = 0.15). Conclusions:, In the present retrospective study of a clinical sample of mild and moderate myopic subjects, family history of myopia did not show predictive value for either the age of first prescription, or the final refractive error developed in adulthood. [source] | ||||||||||