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Myopia is the most common cause of refractive error worldwide. High myopia is a severe type of myopia, which usually accompanies pathological changes in the fundus. To identify high myopia susceptibility genes, DNA-pooling based genome-wide association analysis was used to search for a correlation between single nucleotide polymorphisms and high myopia in a Han Chinese cohort (cases vs. controls in discovery stage: 507 vs. 294; replication stage 1: 991 vs. 1,025; replication stage 2: 1,021 vs. 52,708). Three variants (rs10889602T/G, rs2193015T/C, rs9676191A/C) were identified as being significantly associated with high myopia in the discovery, and replication stage. rs10889602T/G is located at the third intron of phosphodiesterase 4B (PDE4B), whose functional assays were performed by comparing the effects of rs10889602T/T deletion of this risk allele on PDE4B and COL1A1 gene and protein expression levels in the rs10889602T/Tdel/del, rs10889602T/Tdel/wt, and normal control A549 cell lines. The declines in the PDE4B and COL1A1 gene expression levels were larger in the rs10889602T/T deleted A549 cells than in the normal control A549 cells (one-way ANOVA, p < 0.001). The knockdown of PDE4B by siRNA in human scleral fibroblasts led to downregulation of COL1A1. This correspondence between the declines in rs10889602 of the PDE4B gene, PDE4B knockdown, and COL1A1 protein expression levels suggest that PDE4B may be a novel high myopia susceptibility gene, which regulates myopia progression through controlling scleral collagen I expression levels. More studies are needed to determine if there is a correlation between PDE4B and high myopia in other larger sample sized cohorts. [ABSTRACT FROM AUTHOR]

Purpose: Photoreceptor loss plays a role in visual impairment in pathological myopia. As the nutrition and oxygen demands of photoreceptors are mainly supported by the choroidal vessels, we aimed to investigate changes in the choroidal vasculature and their correlations with visual acuity in pathological myopia., Methods: The cohort was composed of 136 eyes from 80 participants, including 42 eyes from 21 participants with emmetropia/low myopia, 48 eyes from 26 participants with simple high myopia, and 46 eyes from 33 participants with pathological myopia. Swept-source optical coherence tomography (OCT) was used to image the eyes with a 12-mm radial line scan protocol. The parameters for 6-mm diameters of macula area centered on the fovea were analyzed. A custom deep learning algorithm based on a modified residual U-Net architecture was used to segment the choroidal boundaries. Then, the distance between the two boundaries was determined and choroidal thickness (CT), luminal area (LA), and stromal area (SA) were demarcated based on Niblack's auto-local threshold algorithm after binarization of the OCT images. Finally, the ratio of LA and total choroidal area was defined as the choroidal vascularity index (CVI). The choroidal parameters in three groups were compared, and correlations of the choroidal parameters with age, gender, axial length, and best-corrected visual acuity (BCVA) were analyzed., Results: The CVI, CT, LA, and SA values were lower in pathological myopia than in emmetropia/low myopia and simple high myopia (P < 0.05). The CT, LA, and SA values were lower in simple high myopia than in emmetropia/low myopia (P < 0.05), whereas there was no difference between the CVIs in the emmetropia/low myopia and high myopia groups (P > 0.05). The CVI was nonlinear with increases in axial length (AL), and there was a critical AL flexion point, approximately 27.26 mm; however, the CT, LA, and SA were negatively correlated with AL. Further analysis showed that only younger subjects (40 years old or less) showed significant AL flexion points. Simple and multiple regression models showed that the CVI was correlated with BCVA (P < 0.05)., Conclusions: Choroidal vascular alterations, especially decreased CVI, occurred in patients with pathological myopia. The CVI decreased with axial elongation beyond the flexion point and was correlated with visual impairment, indicating that the CVI might be a reliable imaging biomarker to monitor the progression of pathological myopia.

Purpose: To characterize biomechanical properties of genipin-crosslinked human dura mater as reinforcing material for posterior scleral reinforcement (PSR) and to compare it with crosslinked human sclera., Methods: Donor dura mater and sclera were crosslinked in the same optimized genipin solution. Resistance to enzyme degradation for both materials were investigated by exposing the materials to accelerated enzyme degrading. Elastic modulus and tensile strength were measured by biomechanics testing equipment. Crosslinked human dura mater was used as reinforcing patch in PSR on 57 adult pathologic myopic eyes. The patients were followed up for an average 3 years. The main outcome was eye globe axial length change and safety profile of the reinforcing material., Results: Crosslinked dura mater demonstrated similar percentage weight loss to crosslinked sclera when exposed to enzymatic solution. Dura mater has higher density than sclera. The retaining elastic modulus after enzyme exposure was 72.02 MPa for crosslinked dura mater while 53.88 MPa for crosslinked sclera, 34% greater for crosslinked dura mater, P = 0.0186). At the end of 3 years follow-up, the mean globe axis of the surgery eyes was reduced by 1.29 mm (from 30.81 to 29.51 mm, P < 0.0001, paired t -test). Visual acuity (BCVA logMar) improved by 0.10 logMar unit which is an improvement of five letters ( P = 0.0184, paired t -test). No material specific complication was noted., Conclusion: Crosslinked human dura mater may be superior to crosslinked human sclera as reinforcing material for PSR to manage progression of high myopia. This material was well tolerated on human eye., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ma, Wu, Liu, Fang, Chu, Zheng, Xue, Nan, Qu and Cheng.)

Objective: We aimed to evaluate anatomical and functional outcomes and determine posterior scleral contraction (PSC) timing in treating myopic traction maculopathy (MTM)., Methods: This is a retrospective study of MTM patients undergoing PSC with genipin cross-linked strip at a single hospital site. Differences in demographic and clinical characteristics were compared among three groups defined by the MTM staging system. All patients were followed up for at least one year postoperatively. The best-corrected visual acuity (BCVA), macular hole diameter, axial length (AL), optical coherence tomography findings, and the complications were evaluated. Additionally, regression analyses were performed to account for confounders., Results: Sixty-one MTM patients (24 eyes at stage 2, 22 eyes at stage 3, and 18 eyes at stage 4) were included. The macular holes were closed in 16 eyes (66.7%), 13 eyes (59.0%), and 11 eyes (61.1%) at stage 2, stage 3, and stage 4, respectively. PSC improved the BCVA in patients at each stage (all P < 0.05). Postoperative BCVA at stage 2 was significantly better than that at stage 4 ( P = 0.0069). Preoperative BCVA was associated with postoperative BCVA ( P < 0.001). Preoperative AL (OR 0.676, 95% CI 0.480 to 0.951, P = 0.025), AL shortening amount (OR 5.129, 95% CI 1.974 to 13.327, P = 0.001) and macular hole diameter (OR 1.003, 95% CI 1.000 to 1.006, P = 0.030) were associated with macular hole closure., Conclusions: PSC is safe and effective in treating MTM at different stages. Early PSC intervention will have more significant visual benefits., Competing Interests: None., (AJTR Copyright © 2022.)

Background: Myopia is the leading cause of refractive errors. As its pathogenesis is poorly understood, we determined if the retinal VIP-VIPR2 signalling pathway axis has a role in controlling signalling output that affects myopia development in mice., Methods: Association analysis meta-study, single-cell transcriptome, bulk RNA sequencing, pharmacological manipulation and VIPR2 gene knockout studies were used to clarify if changes in the VIP-VIPR2 signalling pathway affect refractive development in mice., Results: The SNP rs6979985 of the VIPR2 gene was associated with high myopia in a Chinese Han cohort (randomceffect model: p=0.013). After either 1 or 2 days' form deprivation (FD) retinal VIP mRNA expression was downregulated. Retinal single-cell transcriptome sequencing showed that VIPR2 was expressed mainly by bipolar cells. Furthermore, the cAMP signalling pathway axis was inhibited in some VIPR2 + clusters after 2 days of FD. The selective VIPR2 antagonist PG99-465 induced relative myopia, whereas the selective VIPR2 agonist Ro25-1553 inhibited this response. In Vipr2 knockout ( Vipr2 -KO) mice, refraction was significantly shifted towards myopia (p<0.05). The amplitudes of the bipolar cell derived b-waves in 7-week-old Vipr2 -KO mice were significantly larger than those in their WT littermates (p<0.05)., Conclusions: Loss of VIPR2 function likely compromises bipolar cell function based on presumed changes in signal transduction due to altered signature electrical wave activity output in these mice. As these effects correspond with increases in form deprivation myopia (FDM), the VIP-VIPR2 signalling pathway axis is a viable novel target to control the development of this condition., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Myopia is a good model for understanding the interaction between genetics and environmental stimuli. Here we dissect the biological processes affecting myopia progression., Methods: Human Genetic Analyses: (1) gene set analysis (GSA) of new genome wide association study (GWAS) data for 593 individuals with high myopia (refraction ≤ -6 diopters [D]); (2) over-representation analysis (ORA) of 196 genes with de novo mutations, identified by whole genome sequencing of 45 high-myopia trio families, and (3) ORA of 284 previously reported myopia risk genes. Contributions of the enriched signaling pathways in mediating the genetic and environmental interactions during myopia development were investigated in vivo and in vitro., Results: All three genetic analyses showed significant enrichment of four KEGG signaling pathways, including amphetamine addiction, extracellular matrix (ECM) receptor interaction, neuroactive ligand-receptor interaction, and regulation of actin cytoskeleton pathways. In individuals with extremely high myopia (refraction ≤ -10 D), the GSA of GWAS data revealed significant enrichment of the HIF-1α signaling pathway. Using human scleral fibroblasts, silencing the key nodal genes within protein-protein interaction networks for the enriched pathways antagonized the hypoxia-induced increase in myofibroblast transdifferentiation. In mice, scleral HIF-1α downregulation led to hyperopia, whereas upregulation resulted in myopia. In human subjects, near work, a risk factor for myopia, significantly decreased choroidal blood perfusion, which might cause scleral hypoxia., Interpretation: Our study implicated the HIF-1α signaling pathway in promoting human myopia through mediating interactions between genetic and environmental factors., Funding: National Natural Science Foundation of China grants; Natural Science Foundation of Zhejiang Province., (Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)

Purpose: The purpose of this study was to measure alterations of inner retinal microvascular density and outer retinal sublayer thicknesses in pathological myopia, and to correlate the measured parameters with best corrected visual acuity (BCVA)., Methods: Optical coherence tomography (OCT) and OCT angiography (OCTA) images of 21 control, 48 simple high myopia, and 22 pathological myopia eyes were analyzed to quantify the thicknesses of the outer retinal sublayers and the density of the inner retinal microvascular network that includes the superficial retinal capillary plexus (SRCP) and deep retinal capillary plexus (DRCP). Retinal sublayer thicknesses and microvascular densities were compared among the three groups, and correlations of sublayer thicknesses and microvascular densities with BCVA were determined., Results: In pathological myopia, density of the DRCP, thicknesses of myoid and ellipsoid zone (MEZ), interdigitation zone and retinal pigment epithelium/Bruch complex (IZ + RPE), and choroid were lower than in simple high myopia (P < 0.05). The decreased DRCP density was correlated with thinner MEZ and IZ+RPE in pathological myopia (P < 0.05), but not in simple high myopia (P > 0.05). Simple linear regression showed that axial length, female, thicknesses of outer plexiform layer (OPL), MEZ, IZ + RPE, choroid, and density of the SRCP and DRCP were correlated with BCVA. In multiple regression analysis, worse BCVA was associated only with thinner MEZ, thinner choroid, and decreased DRCP (P < 0.05)., Conclusions: Alteration of inner retinal microvascular density and outer retinal sublayer thicknesses occurred in pathological myopia, especially decreased DRCP and thinner MEZ, which were significantly associated with worse BCVA.

It is controversial that retina and photoreceptors are involved in amblyopic development. Lack of imaging devices for quantitative assessment of photoreceptors in vivo impedes further investigation. In this study we investigated the differences of macular thickness, outer nuclear layer (ONL) thickness and cone density among eyes with unilateral anisometropic amblyopia, amblyopic fellow eyes, and normal control eyes using high-definition spectral-domain optical coherence tomography and adaptive optics imaging system. Thicker fovea and parafovea with characteristic quantitative retinal changes in unilateral amblyopic patients indicated that the amblyopic process might involve the retina. Cones tended to be homogeneously distributed at 1.5° from the foveal center in all participants. However, we did not detect any significant differences in cone density and ONL thickness at 1.5° from the foveal center in patients with unilateral amblyopia when compared with the fellow eyes and the normal control eyes. This is the first study to explore whether photoreceptors are involved in amblyopic development in vivo that would help for understanding the underlying mechanisms of amblyopia. Whether macular changes relate to cone photoreceptors migration of the amblyopic eyes remains to be determined., Competing Interests: None.

Purpose: To investigate structural changes in the retinal outer layers and choroid using adaptive optics (AO) and optical coherence tomography (OCT) in eyes with myopia, and to correlate the changes with decreased macular light sensitivity (MLS)., Methods: This prospective study included 27 subjects with emmetropia and low myopia (EM/LM), 25 with moderate myopia (MM), and 25 with high myopia (HM). Microperimetry was used to quantify MLS in each subject, while AO and OCT images of fundus were analyzed to quantify cone density and regularity and thickness of outer retinal sublayers and choroid. Differences of MLS, cone distribution, and chorioretinal thicknesses were compared among the three groups, and the associations among photoreceptor morphological alterations, MLS, and other parameters were analyzed., Results: In HM, the MLS, cone density and regularity, and thicknesses of the myoid and ellipsoid zone (MEZ), Henle fiber layer and outer nuclear layer, interdigitation zone and RPE/Bruch complex, and choroid were lower than in EM/LM. Decreased MLS was correlated with lower cone density and regularity, and thinner MEZ and choroid in the inner region, and with lower cone density, thinner MEZ and choroid, and longer axial length in the outer region. Multivariate regression showed that better MLS was correlated with thicker MEZ in the inner region and with higher cone density in the outer region., Conclusions: Altered cone distribution and outer retinal thickness, especially cone density and MEZ thickness, were significantly correlated with decline of MLS in HM, which may help to evaluate and monitor visual impairment in HM.

Purpose: To determine the efficacy of posterior scleral contraction (PSC) to treat recurrent or persistent macular detachment after previous vitrectomy in highly myopic eyes., Methods: We reviewed the medical records of patients with high myopia and recurrent or persistent macular detachment after previous vitrectomy treated with PSC at our hospital between April 2013 and March 2017. Fourteen eyes (14 patients; mean age, 58.93 ± 11.08 years) were included. Sclera cross-linked with genipin was used for PSC. The desired axial length decrease was 0.1-fold. The reattachment rate, best-corrected visual acuity, and axial length changes were evaluated., Results: The macular reattachment rate was 100%. In seven eyes with a silicone oil tamponade, the oil was successfully removed 2 weeks to 4 months after surgery. The best-corrected visual acuity improved significantly postoperatively (Snellen acuity improved from 20/1,000-20/400) (1.75 ± 0.90 vs. 1.34 ± 0.58 logarithm of the minimal angle of resolution; P < 0.05). Eight eyes (57.14%) improved; six eyes (43.86%) remained stable. The axial length decreased significantly postoperatively (31.32 ± 3.04 vs. 29.08 ± 3.05 mm; P < 0.05)., Conclusion: Posterior scleral contraction is safe and effective for recurrent and persistent macular detachment after previous vitrectomy in highly myopic eyes. The silicone oil is removed after PSC, and vision can be preserved in these refractory cases.

Objective: To investigate the clinical effectiveness and safety of posterior scleral contraction (PSC) surgery in controlling high myopia in young people., Methods: Twenty patients with high myopia (30 eyes) were treated with PSC. The average age for the patients was 11.45 ± 5.17 years old (range 3-22). A genipin cross-linked sclera was implanted to the posterior sclera in PSC surgery. Axial length and myopia progression rates were measured at least two years before and after PSC surgery., Results: Prior to surgery, the mean AL progression was 0.73 ± 0.33 mm, compared to -0.08 ± 0.31 mm (P=0.00) post-surgery; the degree of myopia increased was -1.40 ± 0.95 D, compared to 0.18 ± 1.10 D post-surgery (P=0.00). The best corrected visual acuity (BCVA, in LogMAR) improved from 0.21 ± 0.16 preoperatively to 0.13 ± 0.13 two years after PSC (P=0.014)., Conclusions: PSC can restrict AL extension and safely control high myopia progression in young people., Competing Interests: None.

Purpose: Myopia has become a global public health problem, particularly in East Asia where myopic retinopathy has become one of the leading causes of blindness and visual impairment in the elderly population. The purpose of this study was to evaluate the efficacy of posterior scleral contraction/reinforcement (PSCR) surgery on controlling the progressive elongation of axial length of highly myopic eyes in young patients., Methods: This is a prospective self-controlled interventional case series. Forty young patients (<18-years old) with progressive high myopia received PSCR with a genipin-crosslinked donor scleral strip for one eye and the fellow eye served as concurrent control without surgery. The main outcome measurement was the change of axial length over 2 to 3 years of follow-up., Results: Immediately after the surgery, axial length was shortened and subsequently increased by 0.32 mm over the follow-up period. In contrast, axial length of the fellow eyes increased by 0.82 mm over the same period (P < 0.001, paired t-test). PSCR delayed axial elongation in eyes with or without staphyloma. No significant change of visual acuity, cornea refractive power, or retina thickness was noted between the surgery and fellow eyes. None of the patients lost visual acuity compared with the baseline. The procedure was well tolerated with only temporary corneal refractive axis shifts that recovered by the 6-month postsurgical visit., Conclusions: PSCR with genipin-crosslinked sclera is safe and effective to restrain eye globe elongation in young patients within a 2- to 3-year follow-up period.

Objective: To study the effects of posterior chamber phakic intraocular lens (IOL) on axial length (AL) measurements and whether a correction factor for later IOL power calculation before cataract surgery is necessary., Methods: Twenty-two high myopic patients (39 eyes) with mean spherical equivalent -19.00 +/- 4.03 D received phakic refractive lens (PRL) implantation, and 24 patients (40 eyes) with mean spherical equivalent (-13.10 +/- 2.53) D received implantable Collamer lens (ICL) implantation. Pre-and postoperative AL measurements with the IOLMaster were compared. Results The pre-and postoperative ALs were (30.87 +/- 2.18) mm and (30.94 +/- 2.16) mm, respectively (t = -2.635, P = 0.012) in the PRL group, and (28.35 +/- 1.20) mm and (28.45 +/- 1.22) mm, respectively ( t = -3.97, P < 0.001) in the ICL group. Linear regression analysis showed: in the PRL group, preoperative AL = 1.01 x postoperative AL-0.24 (R2 = 0.99, P < 0.001), or postoperative AL--preoperative AL = 0.24-0.0055 x postoperative AL; in the ICL group, preoperative AL = 0.96 x postoperative AL +1.17 (R2 = 0.99, P < 0.001), or postoperative AL--preoperative AL = 0.0154 x postoperative AL -0.3763. The mean differences between pre-and postoperative ALs in the PRL and, ICL groups were 0.075 mm and 0.054 mm, respectively., Conclusions: Based on the SRK formula, a < 0.1 mm AL difference would result in a <0.25 D change in the calculated IOL power, possibly a < 0.20 D change in manifest refraction. Furthermore, for PRL, the longer the AL, the smaller the difference between pre-and postoperative ALs. These differences are so small that it is unnecessary to correct IOL power calculation.

High myopia, which is extremely prevalent in the Chinese population, is one of the leading causes of blindness in the world. Genetic factors play a critical role in the development of the condition. To identify the genetic variants associated with high myopia in the Han Chinese, we conducted a genome-wide association study (GWAS) of 493,947 SNPs in 1088 individuals (419 cases and 669 controls) from a Han Chinese cohort and followed up on signals that were associated with p < 1.0 × 10(-4) in three independent cohorts (combined, 2803 cases and 5642 controls). We identified a significant association between high myopia and a variant at 13q12.12 (rs9318086, combined p = 1.91 × 10(-16), heterozygous odds ratio = 1.32, and homozygous odds ratio = 1.64). Furthermore, five additional SNPs (rs9510902, rs3794338, rs1886970, rs7325450, and rs7331047) in the same linkage disequilibrium (LD) block with rs9318086 also proved to be significantly associated with high myopia in the Han Chinese population; p values ranged from 5.46 × 10(-11) to 6.16 × 10(-16). This associated locus contains three genes-MIPEP, C1QTNF9B-AS1, and C1QTNF9B. MIPEP and C1QTNF9B were found to be expressed in the retina and retinal pigment epithelium (RPE) and are more likely than C1QTNF9B-AS1 to be associated with high myopia given the evidence of retinal signaling that controls eye growth. Our results suggest that the variants at 13q12.12 are associated with high myopia., (Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Purpose: The adenosine A(2A) receptor (A(2A)R) modulates collagen synthesis and extracellular matrix production in ocular tissues that contribute to eye growth and the development of myopia. We aimed to determine if single nucleotide polymorphisms (SNPs) in A(2A)R exons associates with high myopia found in Chinese subjects., Methods: DNA samples were prepared from venous lymphocytes of 175 Chinese subjects with high myopia of less than -8.00 diopters (D) correction and 101 ethnically similar controls with between -1.00 D and +1.00 D correction. The coding region sequences of A(2A)R were amplified by PCR and analyzed by Sanger sequencing. The detected variations were confirmed by reverse sequencing. Allelic frequencies of all detected common SNPs were assessed for Hardy-Weinberg equilibrium., Results: Five variations in A(2A)R exons, 5675 A>G, 5765 C>T, 13325 G>A, 13448 C>T, and 14000 T>A, were detected in controls at a low frequency (<1%). However, one SNP, 13772 T>C (rs5751876), showed its polymorphism in 53.3% of the total study population. The rs5751876 is a synonymous substitution located in a tyrosine codon of exon 2. Despite no significant difference in genotype distribution between cases and controls, the frequency of heterozygotes with the rs5751876 genotype was significantly lower in subjects with high myopia., Conclusions: The reduced frequency of the heterozygote rs5751876 genotype in subjects suggests a possible association of A(2A)R with high myopia in a Chinese population.

Purpose: BH3-like motif containing, cell death inducer (BLID) and LOC399959 are two genes associated with the single nucleotide polymorphism (SNP) rs577948, which is a susceptibility locus for high myopia in Japanese subjects. The purpose of this study was to determine if BLID and LOC399959 are associated with high myopia in Chinese Han subjects., Methods: High myopia subjects (n=476) had a spherical refractive error of less than -6.00 D in at least one eye and/or an axial length greater than 26 mm. Genomic DNA was extracted and genotyped from peripheral blood leukocytes of high myopes and controls (n=275). Using a case-control association study of candidate regions, linkage disequilibrium blocks for 19 tag SNPs (tSNPs), including rs577948, harbored within and surrounding the BLID and LOC399959 genes were analyzed on a MassArray platform using iPlex chemistry. Each of the tSNPs had an r(2)>0.8 and minor allele frequency >10% in the Chinese Han population. Haplotype association analysis was performed on Haploview 4.1 using Chi-square (χ(2)) tests., Results: None of the 19 tSNPs were statistically associated with high myopia., Conclusions: While rs577948 may be associated with high myopia in Japanese subjects, it and the other tSNPs near the BLID and LOC399959 genes are not susceptibility loci for high myopia in the Chinese Han population. Thus, associations of SNPs with high myopia as determined by Genome-Wide Association Study (GWAS) may be restricted to certain ethnic or genetically distinct populations. Without systematic replication in other populations, the results of GWAS associations should be interpreted with great caution.

Purpose: High myopia or pathological myopia is a common refractive error. Individuals with high myopia are subject to increased risk of serious eye complications. Accumulating evidence has demonstrated the role for heritability in ocular growth and in the development of high myopia. Retinoic acid and retinoic acid receptors play important roles in ocular development and in experimentally induced myopia. The purpose of this study was to determine if high myopia is associated with single nucleotide polymorphism (SNP) variants in the retinoic acid receptor beta (RARbeta) gene in Chinese subjects., Methods: DNA samples were purified from venous lymphocytes of 175 unrelated Chinese patients with high myopia (less than -8.00 diopters) and 101 Chinese control subjects without high myopia (+/-1.00 diopters). Direct nucleotide sequence analysis in the RARbeta gene was performed, and the detected variations were further confirmed by reverse sequencing. Allelic frequencies of all detected SNPs were assessed for Hardy-Weinberg equilibrium., Results: Five variations in RARbeta were detected in Chinese subjects with high myopia, including 32574G>A, 32629G>A, 32645C>T, 32647T>G, and 151973C>T, of which only 32647T>G (NCBI notes as rs58244688 and rs2067964) had already been reported. The majority of SNP genotypes were heterozygous. While 32647T>G, 32629G>A, and 32645C>T were located in introns and 32574G>A and 151973C>T were located in coding regions, none of the SNPs affected the amino acid sequence. In the present study, no evidence of association was found between variations in the nucleotide sequence of RARbeta and high myopia., Conclusions: Five SNP variants in RARbeta were detected in Chinese subjects with high myopia, none of them were associated significantly with high myopia. Further studies are needed to identify which genes are responsible for high myopia.

Purpose: To investigate the relationship between myopia and changes in ocular biometry and macular thickness in young adults., Methods: Two hundred sixteen eyes from 108 adults (23.3 +/- 6.3 years old, mean +/- SD) were measured for refractive status, corneal curvature, and axial components of the eye. Macular thickness was measured in 118 eyes (59 subjects) by optical coherence tomography. All eyes were categorized into emmetropia, low, moderate, or high myopia based on the refractive status. Biometric results from right eyes of all subjects were compared between sub-groups with the linear correlation analyzed between refraction and other parameters for each group., Results: The vitreous chamber depth was longest in high myopia, followed by the moderate myopia group, the low myopia group and finally the emmetropic group (p < or = 0.004). Average thickness of the inner and outer ring macula in all the myopia groups was significantly thinner than in the emmetropia group (p < or = 0.021). Among different macular regions, the inferior quadrant of the outer ring was consistently the thinnest in myopia. Corneal curvature, anterior chamber depth, and lens thickness measures were not associated with myopia., Conclusions: Myopia in young adults is associated with an increase in vitreous length and a decrease in para-foveal thickness. The thinness in the retinal region inferior to the fovea appears to be more highly correlated with myopia than any other retinal region.

Purpose: To evaluate the effects of angle-supported, iris-fixated and posterior chamber phakic intraocular lens (PIOL) implantation on contrast sensitivity (CS)., Methods: This prospective study included 69 eyes of 41 consecutive cases of high myopia which received an angle-supported (Phakic-6H; 26 eyes), iris-fixated (Verisyse; 23 eyes) or posterior chamber PIOL [phakic refractive lens (PRL); 20 eyes]. Photopic, mesopic and mesopic with glare CS were evaluated preoperatively and at least 6 months postoperatively., Results: In the PRL group, the mean postoperative CS at all frequencies and across all lighting conditions increased. These changes were significant for 6, 12 and 18 cycles per degree (cpd) under both photopic and mesopic conditions (p < 0.01) and for all the tested frequencies under mesopic with glare condition (p < or = 0.01). The average CS was relatively low in the PRL group. These changes were significant for 6 and 12 cpd between the Verisyse and PRL group under photopic condition (p < 0.05), for 3 and 6 cpd under mesopic condition (p < 0.01, p = 0.01) and under mesopic with glare condition (p < 0.01, p < 0.05)., Conclusions: Improvements in postoperative CS confirm that PIOL implantation is a promising alternative for correction of high myopia. In comparison to posterior chamber PIOLs, angle-supported and iris-fixated PIOLs seem to produce a better visual quality in terms of CS, which needs to be warranted by further investigations., ((c) 2007 S. Karger AG, Basel.)