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Myopia is the second leading cause of visual impairment globally. Myopia can induce sight-threatening retinal degeneration and the underlying mechanism remains poorly defined. We generated a model of myopia-induced early-stage retinal degeneration in guinea pigs and investigated the mechanism of action. Methods: The form-deprivation-induced myopia (FDM) was induced in the right eyes of 2~3-week-old guinea pigs using a translucent balloon for 15 weeks. The left eye remained untreated and served as a self-control. Another group of untreated age-matched animals was used as naïve controls. The refractive error and ocular biometrics were measured at 3, 7, 9, 12 and 15 weeks post-FDM induction. Visual function was evaluated by electroretinography. Retinal neurons and synaptic structures were examined by confocal microscopy of immunolabelled retinal sections. The total RNAs were extracted from the retinas and processed for RNA sequencing analysis. Results: The FDM eyes presented a progressive axial length elongation and refractive error development. After 15 weeks of intervention, the average refractive power was −3.40 ± 1.85 D in the FDM eyes, +2.94 ± 0.59 D and +2.69 ± 0.56 D in the self-control and naïve control eyes, respectively. The a-wave amplitude was significantly lower in FDM eyes and these eyes had a significantly lower number of rods, secretagogin+ bipolar cells, and GABAergic amacrine cells in selected retinal areas. RNA-seq analysis showed that 288 genes were upregulated and 119 genes were downregulated in FDM retinas compared to naïve control retinas. In addition, 152 genes were upregulated and 12 were downregulated in FDM retinas compared to self-control retinas. The KEGG enrichment analysis showed that tyrosine metabolism, ABC transporters and inflammatory pathways were upregulated, whereas tight junction, lipid and glycosaminoglycan biosynthesis were downregulated in FDM eyes. Conclusions: The long-term (15-week) FDM in the guinea pig models induced an early-stage retinal degeneration. The dysregulation of the tyrosine metabolism and inflammatory pathways may contribute to the pathogenesis of myopia-induced retinal degeneration.

To introduce and validate the real axial length (RAL)—the distance from the corneal vertex to the posterior choroidal surface measured by swept-source OCT angiography (OCTA). RAL aims to reduce the influence of choroidal thickness on conventional axial length (AL) measurements. The study also compared OCTA-derived parameters with those from the IOL Master 700 to confirm measurement accuracy and established age-specific RAL references in children and adolescents without myopia. This cross-sectional study enrolled Chinese children with normal uncorrected vision. VG 200D and IOL Master700 were used to measure AL, central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth (AQD), and lens thickness (LT). VG 200D additionally provided new AL parameter - RAL. The intraclass correlation coefficient (ICC) and Bland–Altman analysis were applied to assess device concordance in general parameter. Subsequently, VG 200D-derived RAL values were analyzed across age groups. Of 1833 participants aged 5–17 years (909 males, 924 females) were enrolled. The mean RAL was 24.04 mm and the mean AL was 23.52 mm, showing a statistically significant difference ( p  < 0.001), measured by VG 200D. AL were 23.49 ± 0.99 mm and 23.52 ± 1.02 mm respectively in Master 700 and VG 200D, showed good agreement (ICC = 0.956). At age 5, boys exhibited a significantly shorter RAL than girls, with median values of 23.55 mm (interquartile range, IQR: 22.91–23.76 mm) and 22.32 mm (IQR: 21.99–23.15 mm), respectively ( p  = 0.04). By age 17, the RAL increased to 25.26 mm (IQR: 24.75།25.64 mm) in boys and 25.24 mm (IQR: 24.49།25.81 mm) in girls, showing no significant sex difference ( p  = 0.73). RAL exceeded AL by approximately 0.5 mm. The VG 200D demonstrated strong agreement with IOL Master 700 for standard biometric parameters. The difference in RAL length between boys and girls may progressively narrow with increasing age. RAL may offer a valuable tool for objectively evaluating true ocular growth and myopia control efficacy.

This retrospective study investigated circulating immune cell alteration in patients with myopic retinopathy. Blood test results and demographic and ocular information of 392 myopic patients and 129 emmetropia controls who attended Changsha Aier Eye Hospital from May 2017 to April 2022 were used in this study. Compared with emmetropia, the percentages of neutrophils and basophils and neutrophil/lymphocyte ratio were significantly higher in myopic patients, whereas the percentages of monocytes and lymphocytes and the counts of lymphocytes and eosinophils were significantly lower in myopic patients. After adjusting for age and hypertension/diabetes, the difference remained. Interestingly, the platelet counts were significantly lower in myopic patients after the adjustments. Further subgroup analysis using multivariable linear regression showed that higher levels of neutrophils, neutrophil/lymphocyte ratio, and platelet/lymphocyte ratio, lower levels of monocytes, eosinophils, lymphocytes, and platelets, were related to myopic peripheral retinal degeneration (mPRD) and posterior staphyloma (PS). A higher level of basophils was linked to myopic choroidal neovascularization (mCNV). Our results suggest that higher levels of circulating neutrophils and neutrophil/lymphocyte ratio, lower monocytes, eosinophils, lymphocytes, and platelets are related to mild myopic retinopathy. A higher level of circulating basophils is related to the severe form of myopic retinopathy, such as mCNV.

This study aims to explore the role of GABAB receptors in the development of deprivation myopia (DM), lens-induced myopia (LIM) and lens-induced hyperopia (LIH). Chicks were intravitreally injected with 25 µg baclofen (GABABR agonist) in one eye and saline into the fellow eye. Choroidal thickness (ChT) was measured via OCT before and 2, 4, 6, 8, 24 h after injection. ChT decreased strongly at 6 and 8 h after baclofen injection and returned back to baseline level after 24 h. Moreover, chicks were monocularly treated with translucent diffusers, −7D or +7D lenses and randomly assigned to baclofen or saline treatment. DM chicks were injected daily into both eyes, while LIM and LIH chicks were monocularly injected into the lens-wearing eyes, for 4 days. Refractive error, axial length and ChT were measured before and after treatment. Dopamine and its metabolites were analyzed via HPLC. Baclofen significantly reduced the myopic shift and eye growth in DM and LIM eyes. However, it did not change ChT compared to respective saline-injected eyes. On the other hand, baclofen inhibited the hyperopic shift and choroidal thickening in LIH eyes. All the baclofen-injected eyes showed significantly lower vitreal DOPAC content. Since GABA is an inhibitory ubiquitous neurotransmitter, interfering with its signaling affects spatial retinal processing and therefore refractive error development with both diffusers and lenses.

To examine the prevalence of refractive errors in children aged 3-6 years in China. Children were recruited for a trial of a home-based amblyopia screening kit in Guangzhou preschools, during which cycloplegic refractions were measured in both eyes of 2480 children. Cycloplegic refraction (from 3 to 4 drops of 1% cyclopentolate to ensure abolition of the light reflex) was measured by both autorefraction and retinoscopy. Refractive errors were defined as followed: myopia (at least -0.50 D in the worse eye), hyperopia (at least +2.00 D in the worse eye) and astigmatism (at least 1.50 D in the worse eye). Different definitions, as specified in the text, were also used to facilitate comparison with other studies. The mean spherical equivalent refractive error was at least +1.22 D for all ages and both genders. The prevalence of myopia for any definition at any age was at most 2.5%, and lower in most cases. In contrast, the prevalence of hyperopia was generally over 20%, and declined slightly with age. The prevalence of astigmatism was between 6% and 11%. There was very little change in refractive error with age over this age range. Previous reports of less hyperopic mean spherical equivalent refractive error, and more myopia and less hyperopia in children of this age may be due to problems with achieving adequate cycloplegia in children with dark irises. Using up to 4 drops of 1% cyclopentolate may be necessary to accurately measure refractive error in paediatric studies of such children. Our results suggest that children from all ethnic groups may follow a similar pattern of early refractive development, with little myopia and a hyperopic mean spherical equivalent over +1.00 D up to the age of 5-6 years in most conditions.

A psychometric evaluation of the Chinese Impact of Vision Impairment (C-IVI) questionnaire in an adult cohort with high myopia using Rasch Analysis and determination of the relationship between vision-related quality-of-life (VRQoL) and myopia macular degeneration (MMD). We used the baseline visit data of the AIER-Singapore Eye Research Institute (SERI) High Myopia Adult Cohort Study. VRQoL was assessed using the 28-item C-IVI. Rasch analysis was conducted to evaluate the overall C-IVI and domain scores ('Mobility and independence'-MB, 'Reading and accessing information'-RD, and 'Emotional well-being'-EWB), including response category functioning, precision, unidimensionality, targeting, and differential item functioning (DIF). The criterion validity, C-IVI's ability to distinguish participants based on severity of vision impairment (VI), spherical equivalent (SER), and the presence of MMD were analyzed using ANOVA and pairwise t-tests. There were 431 participants, with mean (SD) age of 42.2 (7.1) years, SER of -8.3 (3.8) D, and visual acuity of 0.1 (0.2) LogMAR. Of these, 15.8% presented MMD, 79.4%, 13.5%, 7.0%, and 0.2% had no, mild, moderate, and severe VI, respectively. Response thresholds were ordered for the overall and three domains. The overall range-based precision was 0.94, and 0.80 for each domain. The three domains demonstrated unidimensionality. DIF was uniform in overall and EWB, but not the MB and RD domains. Person estimates decreased with increasing VI severity, worsening SER, and presenting MMD (all p < 0.05) for the overall and domain scores. The C-IVI questionnaire is a valid and reliable tool for assessing VRQoL in adults with high myopia in China.

Total refractive astigmatism is usually the first consideration that guides the selection of contact lens type (e.g., spherical or toric), while the ocular source of the astigmatism is a second, but more important consideration, for the final clinical decision. This study was conducted to provide detailed data on this topic by evaluating astigmatic components in Chinese adolescents. Participants were recruited from healthy high school students undergoing an annual ocular examination at a local hospital. Total astigmatism (TA), corneal astigmatism (CA), and ocular residual astigmatism (ORA) were determined by a Hartmann-Shack wavefront analyzer system (KR-1W, Topcon) with the natural pupil. The axis relationship between CA and ORA was placed into three categories: on-axis, defined as an axis with a difference of 0 ± 10°; opposite-axis, a difference of 90 ± 10°; and the rest defined as oblique-axis. The study consisted of 1,466 students (57.84% girls, age: 16.49 ± 1.05 years). ORA was present in 83.97%, 66.64%, and 45.23% of participants, according to the various criteria for astigmatism (≥ 0.50 D, ≥ 0.75 D, and ≥ 1.00 D, respectively). While with-the-rule was the most common axis orientation for both TA (76.28%) and CA (89.94%), against-the-rule predominated in ORA (93.82%; χ2 = 1688.544, p < 0.001). Opposite-axis was the major type of axis difference (90.96%) of clinical significance (i.e., ≥ 1.00 D) between CA and ORA, which also prevailed in all levels of TA (range: 56.25-82.26%). ORA is common in high school students and usually demonstrates a compensation relationship with CA, which should be taken into consideration when determining the design of contact lenses to correct refractive error.

Ling Zeng,1–3 Zhikuan Yang,1–3 Xiaoning Li,1–3 Heping Xu1–51Aier Academy of Ophthalmology, Central South University, Changsha, People’s Republic of China; 2Changsha Aier Eye Hospital, Changsha, People’s Republic of China; 3Aier Institute of Optometry and Vision Science, Aier Eye Hospital Group, Changsha, People’s Republic of China; 4Aier Eye Institute, Aier Eye Hospital Group, Changsha, People’s Republic of China; 5The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, BT9 7BL, UKCorrespondence: Heping Xu, Email [email protected] Xiaoning Li, Email [email protected]View the original paper by Dr Zeng and colleaguesThis is in response to the Letter to the Editor

To evaluate daily 0.05% atropine's effects on structural changes in the choroid and retina in myopic children. This prospective cohort study included 100 children aged 6-15 years, of whom 83 completed 6-month follow-up. Participants received either nightly 0.05% atropine eyedrops or no pharmacologic treatment (all wore single-vision spectacles). Spherical equivalent (SE) and axial length (AL) were measured, and swept-source OCT angiography was used to assess choroidal thickness (CT), retinal thickness (RT), outer retinal layer (ORL), ganglion cell layer plus inner plexiform layer (GCL+IPL), inner nuclear layer (INL), peripapillary retinal nerve fiber layer (RNFL), choroidal vascular volume (CVV), choroidal vascular index (CVI), superficial and deep vascular complexes (SVC/DVC), and nerve fiber layer vascular density (NFVD). Atropine reduced myopia progression compared to controls (ΔSE: 0.11 vs -0.30 D; ΔAL: 0.01 vs 0.17 mm; < 0.001). In the atropine group, 55.56% showed SE improvement and 42.22% exhibited AL shortening. Significant increases were observed in macular CT, CVV, RT, ORL, GCL+IPL, INL, and peripapillary RT, ORL, and RNFL, whereas CVI, SVC, DVC, and NFVD remained unchanged. Changes in macular CT, CVV, RT, and GCL+IPL were positively correlated with ΔSE and negatively with ΔAL. Increases in ORL and peripapillary RNFL were negatively correlated with ΔAL. Daily 0.05% atropine not only slowed myopia progression and axial elongation but also promoted thickening of choroidal and retinal layers. These structural changes suggest partial reversal of ocular growth, supporting the therapeutic role of atropine in myopia control. Chinese Clinical Trial Registry (ChiCTR2100043506, https://www.chictr.org.cn/showproj.html?proj=122214, registered 21 February 2021). This study represents a secondary analysis of the registered trial; the control group was drawn from an ethically approved observational cohort.

To investigate the relationship between the intraocular levels of complement proteins and myopia-related retinal neuronal and vascular degeneration. Aqueous humour from 147 myopic patients, including 60 low-myopia and 87 high-myopia were collected during Implantable Collamer Lens implantation surgery. All participants received comprehensive ophthalmic examinations, including logMAR best corrected visual acuity, axial length measurement, fundus photography and ocular B-scan ultrasonography. The myopic eyes were further classified into simple myopia (SM, = 78), myopic posterior staphyloma (PS, = 39) and PS with myopic chorioretinal atrophy (PS + CA, = 30). Retinal thickness and vascular density in the macula (6 mm × 6 mm) and optic nerve head (4.5 mm × 4.5 mm) were measured using Optical Coherence Tomography (OCT) and OCT angiography (OCTA). The levels of complement proteins including C1q, C3, C3b/iC3b, C4, CFB, CFH, C2, C4b, C5, C5a, CFD, MBL and CFI in the aqueous humour were measured using the Luminex Multiplexing system. The real-time RT-PCR was conducted to examine the expression of complement genes ( and ) in the guinea pig model of long-term form deprivation-induced myopic retinal degeneration. OCTA showed that retinal neuronal thickness and vascular density in superficial and deep layers of the macular zone as well as vascular density in the optic nerve head were progressively decreased from SM to PS and PS + CA ( < 0.05). The aqueous humour levels of C1q, C3, C3b/iC3b, C4, CFB, CFH, C2, C4b, C5 and CFI were significantly higher in high-myopic eyes compared to those in low-myopic eyes. Further subgroup analysis revealed the highest levels of complement components/fragments in the PS + CA group. The intraocular levels of complement factors particularly C3b/iC3b and C4 were negatively correlated with macular zone deep layer retinal thickness and vascular density and optic nerve head vascular density. The expression of and genes was significantly higher in guinea pig eyes with myopic retinal degeneration compared to control eyes. The intraocular classical pathway and alternative pathway of the complement system are partially activated in pathological myopia. Their activation is related to the degeneration of retinal neurons and the vasculature in the macula and the vasculature in the optic nerve head.