Imbalance Between Oxidative Stress and Growth Factors in Human High Myopia

The role of the KEAP1-NRF2 signaling pathway in form deprivation myopia guinea pigs

In recent years, the global prevalence of myopia has reached an unprecedented level, especially‌ in East Asia. Multitude of studies has shown that the etiology of myopia is complex. Some researchers have suggested that oxidative stress (OS) may contribute to myopia, although there are limited reports on the alterations of related signaling pathways. Notably, the Kelch-like ECH-associated protein 1 (KEAP1) -nuclear factor erythroid 2-related factor 2 (NRF2), which plays a significant role in regulating OS and the mechanism, has not been explored in myopia. To investigate the modulation of KEAP1-NRF2 signaling pathway and its downstream superoxide dismutase (SOD) during the development of form-deprivation myopia, three-week-old guinea pigs were randomly assigned to four groups: negative control (NC), self-control (SC), form-deprivation myopia (FDM), and FDM group treated with tert-butylhydroquinone (TBHQ). Spherical equivalent (SE) and axial length (AL) were measured by retinoscopy and A-scan ultrasound, respectively. The results revealed that TBHQ treatment decelerated the progression in SE and AL changes. Immunohistochemistry (IHC) assessed the distribution and expression of KEAP1, NRF2, and SOD. The results shown that they located in the retinal ganglion cells (RGC). Subsequently, retinal mRNA and protein expression levels of KEAP1, NRF2, and SOD were quantified using real-time polymerase chain reaction (RT-PCR) and Western blot (WB) analysis. The RT-PCR and WB results demonstrated that TBHQ could activate NRF2, induce KEAP1 degradation, and enhance the expression of the antioxidant SOD. In summary, the modulation of KEAP1-NRF2 and it downstream SOD expression could alter the retinal antioxidant capacity and influence the development of myopia.

Systemic Oxidative Stress Level as a Pathological and Prognostic Factor in Myopic Choroidal Neovascularization

Purpose

To investigate the association of systemic oxidative stress level with myopic choroidal neovascularization (mCNV) and its clinical outcomes.

Design

Retrospective case-control study.

Participants

This retrospective study included 52 eyes of 52 healthy participants (mean age: 62.5 years), 30 eyes of 30 patients (mean age: 59.6 years) with high myopia (HM) but without mCNV, and 23 eyes of 23 patients (mean age: 61.8 years) with HM and mCNV who received intravitreal anti-VEGF antibody injections (IVIs) using a pro re nata regimen during the 6-month follow-up after the first IVI.

Methods

Clinical findings, including oxidative stress parameters, such as diacron reactive oxygen metabolites (dROMs), biological antioxidant potential (BAP), and the BAP/dROM ratio (B/d ratio), were analyzed.

Main Outcome Measures

Clinical features and oxidative stress parameters.

Results

Both BAP and the B/d ratio were significantly lower in the HM/mCNV group than in the HM/no mCNV group (P = 0.002 and P = 0.012, respectively) and than in the control group (P = 0.001 and P = 0.026, respectively). In a multiple logistic regression analysis, axial length (odds ratio 1.878, P = 0.042) and the B/d ratio (odds ratio 0.470, P = 0.026) were significantly associated with mCNV. Dividing the patients into high and low B/d ratio groups (with a cutoff of 5.2) showed that subfoveal choroidal thickness (SFCT) was lower (P = 0.002) and the number of IVI treatments was higher (P = 0.029) in the low B/d ratio group than in the high B/d ratio group. In multiple regression analyses, only the B/d ratio was significantly associated with SFCT (β = 0.684, P = 0.006).

Conclusions

The oxidative stress level in eyes with HM differed according to mCNV, SFCT, and the number of IVI treatments. Measuring oxidative stress parameters might be useful in eyes with HM both for assessing the risk of developing mCNV and determining disease activity.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Molecular changes in intraocular fluid: implications for myopia

Myopia is the most common eye disease in the world which is caused by a mismatch between the optical power of the eye and its excessive axial length. Scleral remodeling, oxidative stress, inflammation, pathological states of angiogenesis and fibrosis and metabolism are closely associated with the onset and progression of myopia and the pathological changes that may ultimately result. Intraocular fluid is a collective term for the fluid within the eye, and changes in its composition can reflect the physiological and pathological status within the eye, with aqueous humor and vitreous being the commonly tested specimens. Recent studies have revealed potential changes in a variety of molecules in intraocular fluid during myopia progression. Abnormal expression of these molecules may reflect different stages of myopia and provide new perspectives for disease monitoring and treatment. Therefore, in this review, we systematically review the molecular changes in intraocular fluid associated with myopia, as well as the possible mechanisms, with a view to informing basic myopia research and clinical work.

Lactylome analysis reveals potential target modified proteins in the retina of form-deprivation myopia

The biological mechanisms underlying the development of myopia have not yet been completely elucidated. The retina is critical for visual signal processing, which primarily utilizes aerobic glycolysis to produce lactate as a metabolic end product. Lactate facilitates lysine lactylation (Kla), a posttranslational modification essential for transcriptional regulation. This study found increased glycolytic flux and lactate accumulation in the retinas of form-deprived myopic guinea pigs. Subsequently, a comprehensive analysis of Kla levels in retinal proteins revealed that Kla was upregulated at 124 sites in 92 proteins and downregulated at three sites in three proteins. Functional enrichment and protein interaction analyses showed significant enrichment in pathways related to energy metabolism, including glutathione metabolism, glycolysis, and the hypoxia-inducible factor-1 signaling pathway. Parallel-reaction monitoring confirmed data reliability. These findings suggest a connection between myopia and retinal energy metabolism imbalance, providing new insights into the pathogenesis of myopia.

Reduced retinol (vitamin A) and α-tocopherol (vitamin E) blood levels and increased myeloperoxidase (MPO) activity in children with high myopia

The study assessed selected parameters of redox status in the plasma of patients suffering from high myopia (HM). Thirty-five children with mean age 13.7 ± 2.7 years with HM and 40 healthy children were included. Plasma redox status parameters were determined using colorimetric kits. The levels of retinol, α-tocopherol and coenzyme Q10 were determined with a high-performance liquid chromatograph. Negative correlations were observed between the concentrations of retinol and the axial length of the eye (r = - 0.514 p < 0.001). Increased myeloperoxidase (MPO) activity (p < 0.018), and decreased concentrations of retinol (p < 0.001) and α-tocopherol (p < 0.023) in patients with HM and the axial length of the eye > 26 mm compared to controls were established. Significantly lower retinol and α-tocopherol concentrations were found in patients with the axial length of the eye > 26 mm compared to those with the axial length of the eye ≤ 26 mm (p < 0.001, p < 0.021, respectively). Increased MPO activity in advanced stages of HM may confirm an inflammatory process in HM patients. Reduced retinol and α-tocopherol concentrations and their link to disease progression indicate a need for monitoring their levels and supplementation in children with HM.

Correlation analysis of myopia and dietary factors among primary and secondary school students in Shenyang, China

Currently, the global prevalence of myopia is high and on the rise, seriously affecting the health of students. Studies have suggested that dietary factors may be associated with the occurrence and development of myopia, but the results are inconsistent. This survey aims to analyze the correlation between dietary factors and myopia while controlling for more confounding factors. A multi-stage stratified cluster sampling method was performed to select 10,619 primary and secondary school students in Shenyang for visual examination, and questionnaires were administered to 6974 of them. Logistic regression was performed with myopia as the dependent variable and the variables with p < 0.1 in the univariate analysis as independent variables. Sensitivity analysis was conducted using propensity score matching. The results showed that the overall prevalence of myopia among primary and secondary school students in Shenyang was 59.1%, with mild myopia predominating. Students who ate fresh fruits two or more times a day had a 0.69 times lower risk of myopia compared to those who did not eat fruits (95% CI 0.50-0.97). However, subgroup analysis demonstrated that this protective effect was only significant for male students, with an OR of 0.59 (95% CI 0.38-0.91). Moreover, female students who consumed sugary beverages once or more a day had a 1.8 times higher risk of myopia compared to those who did not consume sugary beverages (95% CI 1.03-3.15). Vegetable consumption, intake of fried foods, and breakfast habits were not significantly associated with myopia. In summary, excessive consumption of sugary beverages could increase the risk of myopia, especially in female students, whereas fruit intake contributed to reducing the risk of myopia, particularly in male students.

Structural, blood flow and functional changes in the macular area and the expression of aqueous humor factors in myopia

Objective

To compare the macular area parameters and aqueous humor factors between myopia and emmetropia.

Methods

Convenience sampling was used to select patients who visited the Changzhi Aier Eye Hospital's department of ophthalmology from December 2018 to December 2022 as the study participants. They were divided into three groups according to whether they were diagnosed as mild myopia myopic, highly myopic or not as follows: the mild myopia group (60 cases, 108 eyes), the high myopia group (46 cases, 78 eyes) and the healthy emmetropia group (40 cases, 65 eyes). The differences in the macular integrity (MI) assessment, optical coherence tomography and optical coherence tomography angiography parameters and aqueous humor factors were compared between the three groups.

Results

AL in high myopia group was the highest, and that in emmetropia group was the lowest. The BCVA of mild myopia group was the highest. The RS in the high myopia group were significantly lowest in the three groups (26.42 ± 1.04 vs. 28.34 ± 0.76 vs. 31.92 ± 0.77) (F = 5.374, p = 0.013). The 63% BCEA, 95% BCEA and MI in the high myopia group were significantly highest (p < 0.05). The mean RPE thickness, mean CT and mean RT in the high myopia group were lowest (p < 0.05). The blood flow density were lowest in the superficial fovea, paracentral fovea and different subdivisions of the paracentral fovea in the high myopia group (p < 0.05). The VEGF concentration in the aqueous humor of the high myopia group was lowest (25.62 ± 17.43 vs. 32.45 ± 24.67 vs. 64.37 ± 21.14) (F = 9.237, p < 0.001). The MMP-2 concentration was highest (483 ± 201.48 vs. 410 ± 142.37 vs. 386 ± 154.34) (F = 5.542, p = 0.018). The VEGF concentration in the aqueous humor factor was negatively correlated with the AL in the myopia group (r = -0.438, p = 0.002), the MMP-2 concentration was positively correlated with the AL (r = 0.484, p = 0.010).

Conclusion

Patients with high myopia showed decreased retinal light sensitivity, fixation stability, superficial blood flow density and retinal thickness compared with people with emmetropia. A decreased VEGF concentration and increased MMP-2 concentration in the aqueous humor factor have potential associations with the development of high myopia.

Glutathione and a Pool of Metabolites Partly Related to Oxidative Stress Are Associated with Low and High Myopia in an Altered Bioenergetic Environment

Oxidative stress forms part of the molecular basis contributing to the development and manifestation of myopia, a refractive error with associated pathology that is increasingly prevalent worldwide and that subsequently leads to an upsurge in degenerative visual impairment due to conditions that are especially associated with high myopia. The purpose of our study was to examine the interrelation of potential oxidative-stress-related metabolites found in the aqueous humor of high-myopic, low-myopic, and non-myopic patients within a clinical study. We conducted a cross-sectional study, selecting two sets of patients undergoing cataract surgery. The first set, which was used to analyze metabolites through an NMR assay, comprised 116 patients. A total of 59 metabolites were assigned and quantified. The PLS-DA score plot clearly showed a separation with minimal overlap between the HM and control samples. The PLS-DA model allowed us to determine 31 major metabolite differences in the aqueous humor of the study groups. Complementary statistical analysis of the data allowed us to determine six metabolites that presented significant differences among the experimental groups (p < 005). A significant number of these metabolites were discovered to have a direct or indirect connection to oxidative stress linked with conditions of myopic eyes. Notably, we identified metabolites associated with bioenergetic pathways and metabolites that have undergone methylation, along with choline and its derivatives. The second set consisted of 73 patients who underwent a glutathione assay. Here, we showed significant variations in both reduced and oxidized glutathione in aqueous humor among all patient groups (p < 0.01) for the first time. Axial length, refractive status, and complete ophthalmologic examination were also recorded, and interrelations among metabolic and clinical parameters were evaluated.

The effect of age on aqueous humor of humans with high myopia

Background

High myopia is a common cause of vision loss. Age is an important factor in the development of high myopia. However, the effect of age on aqueous humor proteins in the context of high myopia is unknown. This study explored the effect of age on the aqueous humor protein of humans with high myopia.

Methods

The aqueous humor of high myopia patients of different ages with implantable collamer lens implantation (ICL) was collected. Data-independent acquisition proteomic analysis was employed to explore differentially expressed proteins (DEPs). Two different bioinformatics analysis methods were used to interpret the proteomic results. Furthermore, three proteins were confirmed by enzyme-linked immunosorbent assay (ELISA).

Results

The study showed 18 upregulated and 20 downregulated proteins. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the upregulated DEPs were highly enriched in coagulation and complement cascades. Weighted gene coexpression network analysis showed that the blue module was identified as a key module for high myopia and that the plasminogen (PLG) protein is a hub protein. ELISA confirmed that the expression levels of Alpha-1-antitrypsin were significantly upregulated in the aqueous humor of older patients presenting with high myopia.

Conclusions

This is the first study to investigate the effect of age on the level of aqueous humor protein in high myopia. Our study provided a comprehensive data set on the overall protein changes of different ages of human high myopia, shedding light on its potential molecular mechanism in high myopia damage to the eyeball.

Analysis and validation of potential ICD-related biomarkers in development of myopia using machine learning

PURPOSE

We aimed to identify and verify potential biomarkers in the development of myopia associated with immunogenic cell death (ICD).

METHODS

We download high myopia (HM) dataset GSE136701 from Gene Expression Omnibus. Differentially expressed genes in HM were identified to overlapped with ICD-related genes. Least absolute shrinkage and selection operator were used to select the Hub genes. Furthermore, the correlation between the hub genes and immune infiltration, immune response activities, and hub genes Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis was investigated using Spearman's rank correlation. Prediction of the miRNAs upstream of the Hub genes was based on the TargetScan database. We used guinea pig lens-induced myopia model's scleral tissues performed quantitative real-time polymerase chain reaction.

RESULTS

We identified overlapped with ICD-related genes (LY96, IL1A, IL33, and AGER) and two genes (LY96 and AGER) as hub genes. Single sample gene set enrichment analysis and Spearman's rank correlation revealed that hub gene expression levels in HM were significantly correlated with the infiltration percentages of CD56dim natural killer cells, macrophages, immature B cells, and the immune response activities of APC co-stimulation and Kyoto Encyclopedia of Genes and Genomes pathways, such as terpenoid backbone biosynthesis, aminoacyl-trna biosynthesis, Huntington's disease, oxidative phosphorylation; there were a few additional signaling pathways compared to normal samples. Additionally, several miRNA were predicted as upstream regulators of LY96 and AGER. LY96 was identified as a significantly differentially expressed biomarker in myopia guinea pig's scleral tissues, as verified by qPCR.

CONCLUSION

LY96 was identified and verified as a ICD-related potential myopia biomarker. Molecular mechanisms or pathways involved in myopia development by LY96 requires further research.

Aqueous humor protein markers in myopia: a review

PURPOSE

Myopia is one of the most common forms of refractive error. Most myopia manifests itself as a relative growth of the eye axis, resulting in a state in which light is projected in front of the retina after being refracted by the refractive system of the eyeball. So far, the specific pathogenesis of myopia is still not well explained, through the results of animal experiments, researchers have proposed various possible scenarios, but all these are based on animal models, and there may still be a certain gap with the mechanism of true myopia in humans. The most readily available in clinical work is aqueous humor obtained during cataract surgery, for which we reviewed these studies of aqueous humor samples from myopic patients.

METHODS

A systematic literature search was done on PubMed using key words including "myopia," "aqueous humor," and "protein."

RESULTS

The results of existing aqueous humor studies have shown that the difference in substances in the aqueous humor of myopia is related to the degradation of the scleral matrix, chronic inflammation of the eye, pro-fibrosis, blood vessel production, and inhibition. There may be more than one reason associated with myopia progression.

CONCLUSION

The specific mechanism of myopia has not been fully elucidated. Therefore, the means of preventing and treating myopia should focus on inhibiting the degradation of the scleral matrix, promoting the proliferation of scleral collagen fibers, and alleviating chronic inflammation of the eyes. Further research into myopic aqueous humor may provide us with new insights.

Nutritional intake, environmental factors, and their impact on myopia prevalence in Korean children aged 5-12 years

BACKGROUND

Myopia is a complex condition influenced by numerous factors, including genetic predisposition, environmental factors, and lifestyle choices. Although evidence indicates that certain dietary factors may influence the development of myopia, this relationship is still not completely understood and is a topic of ongoing research.

METHODS

This study analyzed the relationship between dietary habits, environmental factors, and the prevalence of myopia in a sample of 24,345 children aged 5-12 years from the seventh Korea National Health and Nutrition Examination Survey (KNHANES VII). The average daily intake of dietary nutrients associated with the refractive error status of the participants was analyzed using analysis of variance (GLM) and the Scheffe method for post-hoc comparison. Multiple logistic regression analysis was conducted between the participant's refractive error status and daily dietary nutrient intake, while taking into consideration the age, sex, BMI, parental myopia, and near-work hours.

RESULTS

The risk of myopia increased with age, especially notable between ages 11 and 12, and was higher in children with both parents having myopia. Dietary factors played a crucial role; children with myopia had significantly lower intake of fat, omega-3 fatty acids, and retinol but higher intake of other nutrients compared to emmetropic and hyperopic counterparts. High consumption of carbohydrates, protein, phosphorus, iron, potassium, and sodium was associated with increased myopia risk. High sodium intake was particularly associated with a 2.05-fold increased myopia risk.

CONCLUSIONS

This study highlights the significant role of diet and lifestyle choices in the development of myopia in children. Our findings suggest the importance of considering these specific factors in the management and prevention strategies for myopia, underscoring the need for targeted interventions in children's health and vision care.

Differences in change of post-operative antioxidant levels between laser-assisted lenticule extraction and femtosecond laser in situ keratomileusis

To evaluate the change of total antioxidant capacity (TAC) and ascorbic acid (AA) between femtosecond laser in situ keratomileusis (FS-LASIK) and laser-assisted lenticule extraction (LALEX). A prospective non-randomized study was conducted, and 33 and 75 eyes that had undergone FS-LASIK or LALEX surgeries were enrolled, respectively. The tear films near corneal incisions were collected, and the concentrations of TAC and AA were determined. The generalized linear mixed model was adopted to calculate the adjusted odds ratio (aOR) with 95% confidence interval (CI) of TAC and AA between the two groups. The AA reduction was significant 1 month after the LALEX and FS-LASIK procedures (both p < 0.05), and the decrement in AA level was significantly larger in the FS-LASIK group compared to the LALEX group (p = 0.0002). In the subgroup analysis, the LALEX group demonstrated a lower decrement in TAC level in the individuals with dry eye disease (DED) than the FS-LASIK group (p = 0.0424), and the LALEX group demonstrated a significantly lower AA decrement in the participants with high myopia (p = 0.0165) and DED (p = 0.0043). The LALEX surgery causes lesser AA decrement compared to FS-LASIK surgery especially for the patients with DED.

Association between inflammatory cytokines and oxidative stress levels in aqueous humor with axial length in human myopia

This study investigated the content of inflammatory cytokines and oxidative stress levels in the aqueous humor (AH) of patients with high myopia (HM) and explored the relationship between these factors and the axial length (AL) of the eye, to explore the roles of mild intraocular inflammation and oxidative stress imbalance in the occurrence and development of myopia. AH samples from 40 patients (70 eyes) were collected during implantable collamer lens (ICL-V4c) surgery. The subjects were divided into three groups according to AL: group A (AL ≤ 26 mm), group B (26 < AL ≤ 28 mm), and group C (AL ≥ 28 mm). The concentrations of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), matrix metalloproteinase-2 (MMP-2), and interleukin-1β (IL-1β) in the AH of the three groups were measured using the Luminex system. Oxidative stress levels were measured using reagent kits targeting total antioxidant capacity (T-AOC), catalase (CAT), and nitric oxide (NO) and malonaldehyde (MDA) content. The results showed compared with group A, IL-1β, MMP-2, and IL-6 concentrations were significantly higher and T-AOC levels were significantly lower in group C. There were no significant differences in CAT, NO, MDA, or TNF-α levels among the groups. The concentrations of IL-6 (r = 0.379, p = 0.016), MMP-2 (r = 0.469, p = 0.002), and MDA (r = 0.354, p = 0.025) in AH were positively correlated with the AL, whereas T-AOC (r = -0.678, p = 0.000) was negatively correlated with AL. These results suggest that mild intraocular inflammation and oxidative stress imbalance may be associated with myopia. Further experiments are needed to confirm the role of mild intraocular inflammation and oxidative stress imbalance in the occurrence and development of myopia.

Copper/Zinc Ratio in Childhood and Adolescence: A Review

Both copper (Cu) and zinc (Zn) are crucial micronutrients for human growth and development. This literature review covered the last five years of available evidence on the Cu/Zn ratio in children and adolescents. We searched PubMed, Web of Science, Google Scholar, Cochrane Library, and Science Direct for publications between 2017 and 2022, especially in English, although publications in other languages with abstracts in English were included. The main terms used were "copper", "zinc", "copper-zinc", and "zinc-copper" ratios. Cu and Zn determinations made in blood, plasma, or serum were included. This review comprises several cross-sectional and case-control studies with substantial results. The bibliographic search generated a compilation of 19 articles, in which 63.2% of the studies mostly reported a significantly higher Cu/Zn ratio, and 57.9% of them informed significantly lower levels of Zn. We conclude that children and adolescents with acute and chronic conditions are at greater risk of developing elevated Cu/Zn ratios, related to altered nutritional, infectious, and inflammatory status.

Assessment of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio in patients with high myopia

BACKGROUND

Previous reports have suggested that inflammation levels play a crucial role in the pathogenesis of high myopia (HM). This study aimed to investigate the relationship between HM and systemic inflammation using the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR).

METHODS

Overall, 100 age- and sex-matched participants were recruited for the study, including 50 participants each in the non-HM (NHM) and HM groups. Ocular examinations and blood tests were performed. The NLR and PLR values were calculated from complete blood counts. Receiver operating characteristic (ROC) curves and optimal cut-off values were used to determine the optimal values of the NLR and PLR to distinguish between the HM and NHM groups.

RESULTS

The values of NLR and PLR were significantly elevated in the HM group compared with those in the NHM group (P < 0.001 and P = 0.010, respectively). Axial length (AL) was significantly correlated with the NLR (r = 0.367, P < 0.001) and PLR (r = 0.262, P = 0.009). In the ROC analysis, the NLR value to distinguish between the HM and NHM groups was 0.728; the best cut-off value was 2.68, with 76% sensitivity and 62% specificity. The PLR value to distinguish between the HM and NHM groups was 0.650; the best cut-off value was 139.69, with 52% sensitivity and 76% specificity.

CONCLUSION

The findings of this study indicate that the development of HM may be associated with systemic inflammation measured using the NLR and PLR.

TRIAL REGISTRATION

The study was registered on December 28, 2021 ( http://www.chictr.org.cn ; ChiCTR2100054834).

Next-Generation Sequencing Screening of 43 Families with Non-Syndromic Early-Onset High Myopia: A Clinical and Genetic Study

Early-onset high myopia (EoHM) is a disease that causes a spherical refraction error of ≥-6 diopters before 10 years of age, with potential multiple ocular complications. In this article, we report a clinical and genetic study of 43 families with EoHM recruited in our center. A complete ophthalmological evaluation was performed, and a sample of peripheral blood was obtained from proband and family members. DNA was analyzed using a customized next-generation sequencing panel that included 419 genes related to ophthalmological disorders with a suspected genetic cause, and genes related to EoHM pathogenesis. We detected pathogenic and likely pathogenic variants in 23.9% of the families and detected variants of unknown significance in 76.1%. Of these, 5.7% were found in genes related to non-syndromic EoHM, 48.6% in genes associated with inherited retinal dystrophies that can include a syndromic phenotype, and 45.7% in genes that are not directly related to EoHM or retinal dystrophy. We found no candidate genes in 23% of the patients, which suggests that further studies are needed. We propose a systematic genetic analysis for patients with EoHM because it helps with follow-up, prognosis and genetic counseling.

Refractive Error and Eye Health: An Umbrella Review of Meta-Analyses

Purpose: To explore the associations between refractive errors and multiple eye health outcomes. Methods: This is an umbrella review based on systematic reviews with meta-analyses. In our study, refractive errors included myopia, hyperopia, astigmatism, and anisometropia. We reconducted the meta-analyses whose primary data were available in sufficient detail by random effect model. Heterogeneity was assessed by I ². The main outcomes included myopic macular degeneration (MMD), retinal detachment (RD), cataract, open-angle glaucoma (OAG), strabismus, age-related macular degeneration (AMD), and diabetic retinopathy (DR). Results: Myopia was associated with increased risk of MMD (relative risk = 102.11, 95% CI 52.6-198.22), RD (3.45, 1.08-11.00), nuclear cataract (2.15, 1.53-3.03), posterior subcapsular (PSC) cataract (1.74, 1.41-2.15), OAG (1.95, 1.74-2.19), exotropia (5.23, 2.26-12.09), but decreased risk of DR (0.83, 0.66-1.04), and early AMD (0.80, 0.67-0.94). From mild-to-high myopia, the association strengthened for MMD, RD, nuclear cataract, PSC cataract, OAG, and DR. Hyperopia was associated with an increased risk of early AMD (1.09, 1.01-1.18) and esotropia (22.94, 10.20-51.62). Astigmatism and anisometropia were associated with increased risk of both exotropia and esotropia. Conclusions: Myopia, especially high myopia, demonstrated the highest risk for eye health outcomes, such as MMD, RD, OAG, nuclear and PSC cataracts, and exotropia. However, myopia was associated with a lower risk of early AMD and DR. Individuals with hyperopia are more likely to suffer early AMD and esotropia. Astigmatism and anisometropia predispose to strabismus. A lot of research studies on the mechanism of the associations are needed. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=239744; identifier: 239744.

High Myopia and the Complement System: Factor H in Myopic Maculopathy

High myopia (HM) is both a medical problem and refractive error of the eye owing to excessive eyeball length, which progressively makes eye tissue atrophic, and is one of the main causes for diminishing visual acuity in developed countries. Despite its high prevalence and many genetic and proteomic studies, no molecular pattern exists that explain the degenerative process underlying HM, which predisposes patients to other diseases like glaucoma, cataracts, retinal detachment and chorioretinal atrophy that affect the macular area. To determine the relation between complement Factors H (CFH) and D (CFD) and the maculopathy of patients with degenerative myopia, we studied aqueous humor samples that were collected by aspiration from 122 patients during cataract surgery. Eyes were classified according to eyeball axial length as high myopia (axial length > 26 mm), low myopia (axial length 23.5–25.9 mm) and control (axial length ˂ 23.4 mm). The degree of maculopathy was classified according to fundus oculi findings following IMI’s classification. Subfoveal choroid thickness was measured by optical coherence tomography. CFH and CFD measurements were taken by ELISA. CFH levels were significantly high in the high myopia group vs. the low myopia and control groups (p ˂ 0.05). Significantly high CFH values were found in those eyes with choroid atrophy and neovascularization (p ˂ 0.05). In parallel, the CFH concentration correlated inversely with choroid thickness (R = −0.624). CFD levels did not correlate with maculopathy. All the obtained data seem to suggest that CFH plays a key role in myopic pathology.