Incidence and analysis of intraoperative complications in femtosecond laser-assisted cataract surgery: a large-scale cohort study to establish the learning curve

AIMS

To assess the safety of femtosecond laser-assisted cataract surgery (FLACS) based on surgical parameters and intraoperative complications analysis and to determine the length of the learning curve for FLACS.

METHODS

A prospective consecutive cohort study was conducted on Chinese patients who underwent either FLACS (3289 cases) or contemporaneous conventional phacoemulsification cataract surgery (2130 cases). The laser group was divided into four subgroups in chronological order. We recorded intraoperative complication incidences and compared with surgical parameters between groups. Subgroup analysis was conducted to explore the learning curve of FLACS.

RESULTS

The laser group had a 4.93% incidence of incomplete capsulotomies and a 1.22% incidence of anterior capsule tears. Subgroup analysis showed significant differences in 8 aspects between the first 250 cases (50 cases per surgeon) and the last 2539 cases, but only 2 aspects differed between the second 250 cases (50 cases per surgeon) and the last 2539 cases. There were no significant differences between the third 250 cases (50 cases per surgeon) and the last 2539 cases.

CONCLUSIONS

The intraoperative complications of FLACS were reported, and the learning curve is associated with a significant reduction in the incidence of intraoperative complications. The length of the basic learning curve of FLACS is 100 cases, and the length of the advanced learning curve was 150 cases. This study demonstrated that FLACS is characterised by a relatively straightforward and secure operative technique.

Targeted dexamethasone nano-prodrug for corneal neovascularization management

BACKGROUND

To overcome the drawbacks of traditional therapy for corneal neovascularization (CNV), we evaluated the efficacy of polyethylene glycol (PEG)-conjugated Ala-Pro-Arg-Pro-Gly (APRPG) peptide modified dexamethasone (Dex), a novel nano-prodrug (Dex-PEG-APRPG, DPA).

METHODS

Characterization of DPA nano-prodrug were measured with transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses. Cytotoxicity and effects on cell migration and tube formation of DPA were evaluated in vitro. A murine CNV model was established by cornea alkali burn. The injured corneas were given eye drops of DPA (0.2 mM), Dex solution (0.2 mM), Dexp (2 mM), or normal saline three times a day. After two weeks, eyes were obtained for the analysis of histopathology, immunostaining, and mRNA expression.

RESULTS

DPA with an average diameter of 30 nm, presented little cytotoxicity and had good ocular biocompatibility. More importantly, DPA showed specific targeting to vascular endothelial cells with efficient inhibition on cell migration and tube formation. In a mouse CNV model, clinical, histological, and immunohistochemical examination results revealed DPA had a much stronger angiogenesis suppression than Dex, resembling a clinical drug with an order of magnitude higher concentration. This was ascribed to the significant downregulations in the expression of pro-angiogenic and pro-inflammatory factors in the corneas. In vivo imaging results also demonstrated that APRPG could prolong ocular retention time.

CONCLUSIONS

This study suggests that DPA nano-prodrug occupies advantages of specific targeting ability and improved bioavailability over conventional therapy, and holds great potential for safe and efficient CNV therapy.

Clinical significance of CTGF and Cry61 protein in extraocular muscles of strabismic patients

PURPOSE

To investigate the relationship between clinical features and protein amounts of Cysteine-rich 61 (Cyr61/CCN1) and connective tissue growth factor (CTGF/CCN2), which are vital components and regulators of the extracellular matrix in resected muscles from strabismus surgery.

METHODS

Strabismus patients who were diagnosed with horizontal concomitant strabismus or inferior oblique overaction (IOOA) and required extraocular muscles (EOMs) resection to correct eye position were included in this study. The protein amounts were measured by enzyme-linked immunosorbent assay (ELISA) in resected EOMs. Multivariable linear regression was used to investigate the associations, adjusting for gender, age (continuous), amblyopia, and disease duration.

RESULTS

A total of 141 muscles (including 38 lateral, 81 medial rectus, and 22 inferior oblique muscles) from 128 patients were collected in this study. The amount of Cry61 and CTGF per millimeter was significantly negatively associated with deviation angle in intermittent exotropia patients (Cry61: β, - 1.44; 95%CI, - 2.79 to - 0.10, p = 0.035; CTGF: β, - 3.14; 95%CI, - 5.06 to - 1.22, p = 0.002). The same relationship was also detected in the partially accommodative and non-accommodative esotropia patients, although it was not statistically significant (Cry61: β, - 2.40; 95%CI, - 5.05 to 0.24; p = 0.073; CTGF: β, - 3.47; 95%CI, - 9.18 to 2.87; p = 0.269). The amount of Cry61 and CTGF per millimeter showed significant associations with the degree of IOOA (p < 0.05).

CONCLUSIONS

Taken together, our results demonstrated a significant relationship between deviation angle and protein amount of Cry61 and CTGF and implied that Cry61 and CTGF may play important roles in modulation of EOM contractility, which provide new insights into strabismus pathogenesis.

Glycolysis Aids in Human Lens Epithelial Cells' Adaptation to Hypoxia

Hypoxic environments are known to trigger pathological damage in multiple cellular subtypes. Interestingly, the lens is a naturally hypoxic tissue, with glycolysis serving as its main source of energy. Hypoxia is essential for maintaining the long-term transparency of the lens in addition to avoiding nuclear cataracts. Herein, we explore the complex mechanisms by which lens epithelial cells adapt to hypoxic conditions while maintaining their normal growth and metabolic activity. Our data show that the glycolysis pathway is significantly upregulated during human lens epithelial (HLE) cells exposure to hypoxia. The inhibition of glycolysis under hypoxic conditions incited endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) production in HLE cells, leading to cellular apoptosis. After ATP was replenished, the damage to the cells was not completely recovered, and ER stress, ROS production, and cell apoptosis still occurred. These results suggest that glycolysis not only performs energy metabolism in the process of HLE cells adapting to hypoxia, but also helps them continuously resist cell apoptosis caused by ER stress and ROS production. Furthermore, our proteomic atlas provides possible rescue mechanisms for cellular damage caused by hypoxia.

Insight into Pathogenic Mechanism Underlying the Hereditary Cataract Caused by βB2-G149V Mutation

Congenital cataracts account for approximately 5-20% of childhood blindness worldwide and 22-30% of childhood blindness in developing countries. Genetic disorders are the primary cause of congenital cataracts. In this work, we investigated the underlying molecular mechanism of G149V point missense mutation in βB2-crystallin, which was first identified in a three-generation Chinese family with two affected members diagnosed with congenital cataracts. Spectroscopic experiments were performed to determine the structural differences between the wild type (WT) and the G149V mutant of βB2-crystallin. The results showed that the G149V mutation significantly changed the secondary and tertiary structure of βB2-crystallin. The polarity of the tryptophan microenvironment and the hydrophobicity of the mutant protein increased. The G149V mutation made the protein structure loose and the interaction between oligomers was reduced, which decreased the stability of the protein. Furthermore, we compared βB2-crystallin WT and the G149V mutant with their biophysical properties under environmental stress. We found that the G149V mutation makes βB2-crystallin more sensitive to environmental stresses (oxidative stress, UV irradiation, and heat shock) and more likely to aggregate and form precipitation. These features might be important to the pathogenesis of βB2-crystallin G149V mutant related to congenital cataracts.

Znf469 Plays a Critical Role in Regulating Synthesis of ECM: A Zebrafish Model of Brittle Cornea Syndrome

Purpose

Brittle cornea syndrome (BCS) is a rare autosomal recessive disorder characterized by extreme thinning and fragility of the cornea, and mutations in ZNF469 cause BCS-1. We aimed to establish a znf469 mutant zebrafish line to explore its roles and possible pathogenic mechanism in cornea development and disorder.

Methods

znf4694del/4del mutant zebrafish was generated using the CRISPR/Cas9 technology. Transmission electron microscopy (TEM) was performed to examine the phenotype of the cornea in different developmental stages. RNA sequencing and quantitative real-time polymerase chain reaction were used to reveal the molecular mechanism.

Results

Macroscopically, homozygous znf469 mutant zebrafish larvae exhibited a curved body from 72 hours postfertilization, similar to kyphoscoliosis, and a noninflated swimbladder at 7 days postfertilization (dpf). TEM revealed an extreme reduction of corneal stroma thickness in homozygous znf469 mutant zebrafish in both the central and peripheral cornea from the early development stage. RNA-sequencing analysis demonstrated that the znf469 mutation leads to the decreased synthesis of various extracellular matrix (ECM) components, such as collagens and proteoglycans, but increased synthesis of 26S proteasome family members.

Conclusions

The results of our work indicate that znf469 is a critical gene that, as a widely considered transcription factor, may regulate the synthesis and degradation of a large number of ECM components that play an important role in corneal development.

Role of Rapamycin and 3-MA in oxidative damage of HLECs caused by two doses of UVB radiation

Background

This study compared the role of autophagy regulators Rapamycin and 3-MA in oxidative damage and apoptosis of human lens epithelial cells (HLECs) caused by two doses of Ultraviolet Radiation B (UVB).

Methods

HLECs were irradiated with UVB, and two doses of UVB damage models were constructed. After treatment with autophagy regulators, cell damage tests such as CCK-8, LDH activity, and Ros detection were performed. Western blotting was used to detect the levels of autophagy-related proteins and apoptosis-related proteins. Quantitative real-time PCR (RT-qPCR) was used to detect the mRNA leve of secondary antioxidant enzymes.Flow cytometry was used to examine cell viability and apoptosis. Finally, the proportion of autophagy and apoptosis was observed by electron microscope.

Results

Autophagy inhibitor 3-MA promoted oxidative damage and apoptosis of HLECs at low doses of UVB (5 mJ/cm2), which corresponds to 1.3 ​h of exposure to sunlight in human eyes. Under the high dose of UVB (50mJ/cm2), which is equivalent to 13 ​h of exposure to sunlight in human eyes, the autophagy inducer Rapamycin caused more extensive oxidative damage and apoptosis of HLECs. 3-MA was able to reduce this damage, indicating that moderate autophagy is necessary for HLECs to cope with mild oxidative stress. For high dose UVB-induced oxidative stress, the use of 3-MA inhibiting autophagy is more beneficial to reduce cell damage and apoptosis. The mechanisms include degradation of damaged organelles, regulation of the expression of antioxidant enzymes HO-1, NQO1, GCS and regulation of apoptosis-related proteins.

Conclusions

Autophagy played different roles in HLECs oxidative stress induced by two doses of UVB. It provides new ideas for reducing oxidative damage and apoptosis of HLECs to prevent or delay the progression of age-related cataract (ARC).

TP53INP2 Contributes to TGF-β2-Induced Autophagy during the Epithelial–Mesenchymal Transition in Posterior Capsular Opacification Development

Background: Posterior capsule opacification (PCO) is the most common complication after cataract surgery, in which increased levels of transforming growth factor-beta 2 (TGF-β2) accelerate PCO formation; however, the pathological mechanisms are not fully understood. This study aims to explore the regulation mechanism of TGF-β2 in PCO formation via its autophagic functions. Methods: The autophagic effect of TGF-β2 was detected by transmission electron microscopy (TEM), Western blotting, and immunofluorescence analysis. The association between autophagy and the epithelial–mesenchymal transition (EMT) was evaluated by qPCR and Western blotting. The transcriptome analysis was used to uncover the molecular mechanism of TGF-β2-induced PCO formation. Results: TGF-β2 specifically promotes autophagy flux in human lens epithelial cells. The activation of autophagy by rapamycin can promote EMT marker synthesis and improve cell migration. However, the inhibition of autophagy by 3-MA attenuates EMT. To uncover the molecular mechanisms, we performed RNA sequencing and found that TGF-β2 elevated tumor protein p53-inducible nuclear protein2 (TP53INP2) expression, which was accompanied by a nuclear-to-cytoplasm translocation. Moreover, the knockdown of TP53INP2 blocked the TGF-β2-induced autophagy and EMT processes, revealing that TP53INP2 plays an important role in TGF-β2-induced autophagy during EMT. Conclusions: Taken together, the results of this study suggested that TP53INP2 was a novel regulator of PCO development by TGF-β2, and notably, TP53INP2, may be a potential target for the pharmacological treatment of PCO.

Anti-Oxidative and Anti-Inflammatory Micelles: Break the Dry Eye Vicious Cycle

Dry eye disease (DED) impacts ≈30% of the world's population and causes serious ocular discomfort and even visual impairment. Inflammation is one core cause of the DED vicious cycle, a multifactorial deterioration in DED process. However, there are also reactive oxygen species (ROS) regulating inflammation and other points in the cycle from the upstream, leading to treatment failure of current therapies merely targeting inflammation. Accordingly, the authors develop micelle-based eye drops (more specifically p38 mitogen-activated protein kinases (MAPK) inhibitor Losmapimod (Los)-loaded and ROS scavenger Tempo (Tem)-conjugated cationic polypeptide micelles, designated as MTem/Los) for safe and efficient DED management. Cationic MTem/Los improve ocular retention of conjugated water-soluble Tem and loaded water-insoluble Los via electrostatic interaction with negatively charged mucin on the cornea, enabling an increase in therapeutic efficiency and a decrease in dosing frequency. Mechanistically, MTem/Los effectively decrease ROS over-production, reduce the expression of proinflammatory cytokines and chemokines, restrain macrophage proinflammatory phenotypic transformation, and inhibit cell apoptosis. Therapeutically, the dual-functional MTem/Los suppress the inflammatory response, reverse corneal epithelial defect, save goblet cell dysfunction, and recover tear secretion, thus breaking the vicious cycle and alleviating the DED. Moreover, MTem/Los exhibit excellent biocompatibility and tolerability for potential application as a simple and rapid treatment of oxidative stress- and inflammation-induced disorders, including DED.

Necroptosis Contributes to Airborne Particulate Matter-Induced Ocular Surface Injury

In this study, we explored the role of necroptosis in the pathogenesis of ocular surface injury caused by airborne particulate matter (PM). Human corneal epithelial (HCE) cells and mouse ocular surface were treated with PM exposure and compared with non-exposed groups. The expression of necroptosis-related proteins was measured by immunoblotting in HCE cell groups. Cell damages were detected using CCK-8, flow cytometry, and immunofluorescence staining. In the mouse model, hematoxylin and eosin (H&E) staining and corneal fluorescein sodium staining were assessed. In addition, the expression of inflammatory cytokines and mucin were examined via Enzyme-linked immunosorbent assay (ELISA), immunofluorescence staining and/or quantitative RT -PCR (qRT-PCR), both in vitro and in vivo. Our research showed that PM exposure may trigger HCE cell damage via necroptosis. Necrostatin-1(Nec-1), one of the specific inhibitors of necroptosis, can markedly reduce PM-induced HCE cell damage. HCE cell damage markers included decreased cell viability, increased intracellular reactive oxygen species (ROS) levels, and loss of mitochondrial membrane potential. At the same time, Nec-1 inhibited the increased inflammatory cytokines and the decreased mucin expression caused by PM exposure in HCE cells. Nec-1 also reduced corneal inflammation and mucin underproduction in mouse ocular surface after PM exposure. Our study demonstrated that necroptosis is involved in the pathogenesis of PM exposure-related ocular surface injury, including inflammation and insufficient mucin production in the cornea, which can be rescued by inhibitor Nec-1. This suggests Nec-1 could be a novel therapeutic target for ocular surface disorders, especially dry eye disease, which is caused by the exacerbation of airborne PM pollution.

Cataract-causing mutation R48C increases γA-crystallin susceptibility to oxidative stress and ultraviolet radiation

Among all congenital cataracts caused by genetic mutations, approximately half are caused by a mutation in crystallin genes, and accounts the leading cause of blindness in children globally. In this study, we investigated the underlying molecular mechanism of R48C mutation (c.142C > T; p.[Arg48Cys]) of γA-crystallin in a Mexican-Mestizo descent family causing congenital cataracts. We purified γA-crystallin wild-type (WT) and R48C mutant and compared their structural characteristics and biophysical properties by Spectroscopic experiments and environmental stress (oxidative stress, ultraviolet irradiation, pH disorders, thermal shock, or chemical denaturation). The R48C mutant did not affect the secondary and tertiary structure of monomer γA-crystallin, nor did it affect its stability to heat shock and chemicals. However, the R48C mutant destroys the oxidative stability of γA-crystallin, which makes the protein more prone to aggregation and precipitation under oxidative conditions. These might be the pathogenesis of γA-crystallin R48C mutant related to congenital cataract and help to develop anti-cataract strategies from the perspective of γA-crystallin.

Rapamycin relieves the cataract caused by ablation of Gja8b through stimulating autophagy in zebrafish

Macroautophagy/autophagy is known to be important for intracellular quality control in the lens. GJA8 is a major gap junction protein in vertebrate lenses. Mutations in GJA8 cause cataracts in humans. The well-known cataractogenesis mechanism is that mutated GJA8 leads to abnormal assembly of gap junctions, resulting in defects in intercellular communication among lens cells. In this study, we observed that ablation of Gja8b (a homolog of mammalian GJA8) in zebrafish led to severe defects in organelle degradation, an important cause of cataractogenesis in developing lens. The role of autophagy in organelle degradation in lens remains disputable. Intriguingly, we also observed that ablation of Gja8b induced deficient autophagy in the lens. More importantly, in vivo treatment of zebrafish with rapamycin, an autophagy activator that inhibits MAPK/JNK and MTORC1 signaling, stimulated autophagy in the lens and relieved the defects in organelle degradation, resulting in the mitigation of cataracts in gja8b mutant zebrafish. Conversely, inhibition of autophagy by treatment with the chemical reagent 3-MA blocked these recovery effects, suggesting the important roles of autophagy in organelle degradation in the lens in gja8b mutant zebrafish. Further studies in HLE cells revealed that GJA8 interacted with ATG proteins. Overexpression of GJA8 stimulated autophagy in HLE cells. These data suggest an unrecognized cataractogenesis mechanism caused by ablation of Gja8b and a potential treatment for cataracts by stimulating autophagy in the lens.Abbreviations: 3-MA: 3-methyladenine; ATG: autophagy related; AV: autophagic vacuoles; Dpf: days post fertilization; GJA1: gap junction protein alpha 1; GJA3: gap junction protein alpha 3; GJA8: gap junction protein alpha 8; Hpf: hours post fertilization; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PtdIns3K: class III phosphatidylinositol 3-kinase; WT: wild type.

Integrated Transcriptomic and Proteomic Analysis Reveals Up-Regulation of Apoptosis and Small Heat Shock Proteins in Lens of Rats Under Low Temperature

Cold cataract is the reversible opacification of the lens when the temperature decreases. However, we observed that when temperature of the rats’ lens was maintained at a lower temperature for a prolonged time, the opacification of lens was only partly reversible. To review the potential molecular mechanism of the irreversible part of opacification under cold stimulation, we applied comparative transcriptomic and proteomic analysis to systematically investigate the molecular changes that occurred in the lens capsules of rats under low temperature treatments. The RNA sequencing based transcriptomic analysis showed a significant up-regulation of genes related to the lens structure and development in the Hypothermia Group. Hub genes were small heat shock proteins (sHSPs). Besides the same findings as the transcriptomic results, the liquid chromatography-tandem mass spectrometry based proteomic analysis also revealed the up-regulation of the apoptotic process. To further analyze the regulatory mechanism in this process, we subsequently performed integrated analysis and identified the down-regulation of Notch3/Hes1 and PI3K/Akt/Xiap signaling axis. Our research revealed the activation of the apoptotic process in rats’ lens under cold stimulation, and the sHSP related heat shock response as a potential protective factor through our transcriptomic and proteomic data.

Optical Coherence Tomography Angiography-Based Quantitative Assessment of Morphologic Changes in Active Myopic Choroidal Neovascularization During Anti-vascular Endothelial Growth Factor Therapy

Purpose: To establish quantitative profile of the morphologic changes among patients with active myopic choroidal neovascularization (mCNV) before and after anti-vascular endothelial growth factor (VEGF) therapy using optical coherence tomography angiography (OCTA) to assess the therapeutic response.

Methods: Patients with active mCNV who received anti-VEGF injections between February 2017 to October 2020 and fit the study criteria were retrospectively reviewed. Quantitative analysis of their OCTA images were carried out to evaluate the morphologic features and vascular changes of mCNV lesions in response to anti-VEGF therapy. For further quantitative profiling, mCNV area, fractal dimension, vessel area, vessel density, vessel diameter, vessel length, vessel junction, junction density, and vessel tortuosity were obtained by means of advanced skeletonization postprocessing analyses.

Results: Thirty-one eyes of 29 consecutive patients with OCTA-positive mCNV lesions (mean spherical equivalent: −12.55 ± 3.24 diopters) were included. The 31 cases were divided into two phenotypes at baseline: organized interlacing pattern (83.87%) and disorganized vascular loops pattern (16.13%). The values of mCNV area, fractal dimension, vessel area, vessel length, vessel junction, and junction density decreased remarkably 1 month after the initial anti-VEGF injection (p < 0.001). Although, vessel density, vessel diameter, and vessel tortuosity increased meanwhile, only vessel diameter displayed statistical significance (p = 0.027). Of note, relative ratio analysis showed that vessel junction was the most sensitive biomarker in response to anti-VEGF therapy, reflecting a mean decrease of 50.36%. Sensitivity lowered successively in biomarkers of vessel length, vessel area, junction density, mCNV area, and fractal dimension. In addition, percent change of mCNV area (r = 0.552, p = 0.002), fractal dimension (r = 0.446, p = 0.017), vessel area (r = 0.518, p = 0.005), and vessel length (r = 0.440, p = 0.019) were moderately associated with that of central retinal thickness.

Conclusions: The study showed morphological as well as quantitative changes on OCTA responding to anti-VEGF treatment in mCNV patients, among which vessel junctions might be the most predictive biomarker. OCTA-based analysis, providing intuitive images and a large spectrum of quantitative data at the same time, could promote new insights into the therapeutic response assessment in mCNV patients.

KPNA4 is involved in cataract formation via the nuclear import of p53

KPNA4 (also called importin-α3) belongs to the importin α adaptor proteins family, which orchestrates classical nuclear transport processes, importin-α/importin-β1 pathway, and involves in cellular homeostasis. Disruption of balanced transport pathways may result in ectopic nuclear proteins and eventually cause diseases, mainly under the situation of cellular stress, such as oxidative stress. Little evidence is available on its cellular functions for high specific expression in lens. We firstly studied the role of KPNA4 in cataract formation. Lens defects were observed at an early age in kpna4 gene knockout zebrafish, generated by the CRISPR/Cas9 system. Those phenotype, including cloudy center part of the lens, via bright field microscopy, and the thinning of the LE layer, wider space between the adjacent LE and LF cells, irregular cells morphology and the increased number of holes inside the LE cells, which were detected by transmission electron microscopy, recapitulate the clinical features of cataract patients. As the p53-specific adaptor of the nuclear import, KPNA4 upregulated with the same pattern of p53 in hydrogen peroxide-induced apoptosis in human lens epithelia cells. Furthermore, the loss of Kpna4 resulted in the accumulation of p53 in the center of lens. Taken together, we showed that KPNA4 was involved in the formation of cataract, likely by mediating p53 nuclear transport.

Parameters of Capsulorrhexis and Intraocular Lens Decentration After Femtosecond and Manual Capsulotomies in High Myopic Patients With Cataracts

Purpose: To compare the parameters of capsulorrhexis and intraocular lens decentration after femtosecond laser capsulotomy and manual continuous curvilinear capsulorrhexis in high myopic patients with cataracts. Methods: This is a prospective consecutive non-randomized comparative cohort study. Selected patients with axial length > 26.0 mm were divided into femtosecond laser capsulotomy (FS) group and manual continuous curvilinear capsulorrhexis (CCC) group. Five experienced phacoemulsification surgeons conducted all surgeries. Intraoperative complications and post-operative anterior segment photography were recorded. Intraocular lens decentration, area of capsulorrhexis, circularity, and capsule overlap were measured at 1 week, 1 month, and 2 years after surgery. Between group differences of parameters were determined with independent-sample t-test or the Mann-Whitney U-test, analysis of variance test, Pearson chi-square test, and Spearman rank correlation test. Results: The study included 142 eyes (108 patients), 68 eyes in the FS group, and 74 eyes in the CCC group. At 1 week, 1 month, and 2 years after surgery, the area of capsulorrhexis in the CCC group was significantly larger than in the FS group (P < 0.05), while no significant difference was noted in circularity values. The complete overlap ratio in the FS group was significantly higher than that in the CCC group (P < 0.05) at each measured timepoint. Significant correlations were noted between the anterior chamber depth and the area of capsulorrhexis in the CCC group (R = 0.25, P = 0.04), but did not correlate in the FS group (P > 0.05). In patients with an anterior chamber depth >3 mm, the capsule-intraocular lens (IOL) overlap of the CCC group was less than that of the FS group at all measured timepoints after surgery (P < 0.05). Meanwhile, the IOL decentration in the CCC group was significantly greater than that of the FS group in those patients at 2 years after surgery (P < 0.05). Conclusion: In high myopic patients with cataracts, with anterior chamber depth more than 3 mm, femtosecond laser capsulotomy can achieve better capsulorrhexis sizing and centering. Due to more precise capsulotomy and a better capsule-IOL overlap in the FS group, femtosecond laser capsulotomy resulted in better long-term centration of the IOL.

Ultrastructural and immunofluorescence analysis of anterior lens capsules in autosomal recessive Alport syndrome

Background: To first report and study the ultrastructural and immunofluorescence abnormalities of the lens anterior capsules in a patient with autosomal recessive Alport syndrome.Methods: Two anterior lens capsules were collected in femtosecond laser-assisted cataract surgeries from a 29-year-old male patient with bilateral lenticonus caused by autosomal recessive Alport syndrome. The left capsule was examined by transmission electron microscopy and the right capsule was serial sectioned and stained with antibodies against the α2, α3, and α4 chains of type Ⅳ collagen. Anterior lens capsules of another two uncomplicated age-related cataract patients were collected and treated in the same way as the control.Results: The novel findings are that the mitochondria in lens epithelial cells in autosomal recessive Alport syndrome patients increased, twisted, and exhibited high electron density. Characteristic ultrastructure changes of capsule thinning, vertical dehiscence, and irregular-shaped lens epithelial cells were also observed in the left anterior lens capsule. Normal reactivity against the α2 chain and decreased reactivity against the α3 and α4 chains were observed in the right anterior lens capsule.Conclusions: The homozygous c.4599 T > G mutation of COL4A4 not only affects the formation of type Ⅳ collagen networks in the extracellular matrix, but also affects the morphology and survival of the lens epithelial cells in the patient with autosomal recessive Alport syndrome. This study is the first report of the ultrastructural and immunofluorescence changes of anterior lens capsules in autosomal recessive Alport syndrome.

Cytoprotective role of humanin in lens epithelial cell oxidative stress‑induced injury

Oxidative stress-induced injury and apoptosis of human lens epithelial cells (HLECs) are early events in the development of age-related cataracts (ARCs). Humanin (HN) is a mitochondrial-related peptide that serves a cytoprotective role in various cell types and animal models. Following HN knockdown or overexpression, the level of reactive oxygen species (ROS), mitochondrial membrane potential and mitochondrial DNA copy number, cell viability, LDH activity and apoptosis of HLECs under oxidative stress were detected, and apoptosis and autophagy were detected via transmission electron microscopy. The results suggested that HN may be involved in the response of HLECs to oxidative stress, and that HN expression was significantly upregulated under oxidative stress conditions. Furthermore, exogenous HN reduced intracellular ROS content and mitochondrial damage, and enhanced mitochondrial biosynthesis; however, this protection was lost in an endogenous HN knockdown cell model. In addition, to the best of our knowledge, the present study was the first to identify that HN increased mitochondrial autophagy, which was involved in reducing ROS production under oxidative stress. The present study indicated a potential mechanism underlying the anti-oxidative damage and apoptotic effects of HN under oxidative stress. In conclusion, HN may be a potential therapeutic target for ARCs as it has a significant cellular protective effect on HLECs under oxidative stress; therefore, further study is required to investigate its role in the occurrence and development of ARCs.

Development of mucoadhesive cationic polypeptide micelles for sustained cabozantinib release and inhibition of corneal neovascularization

Corneal neovascularization (CNV) is one of the leading risk factors for vision loss. Anti-angiogenic drugs can theoretically be extended to the treatment of CNV. However, the application of these drugs is often hindered by traditional administration methods, e.g., eye drops, which is ascribed to the unique structure of the cornea and tear film. In this study, cationic polypeptide nanoparticles with mucoadhesive ability that carry lipophilic cabozantinib (a tyrosine kinase inhibitor), called Cabo-NPs, were developed for sustained cabozantinib release and inhibition of CNV. The polypeptides were synthesized via N-carboxyanhydride ring-opening polymerization and could self-assemble into micelles with cabozantinib in aqueous solution. The Cabo-NPs possessed good biocompatibility both in corneal epithelial cells and mouse corneas. More importantly, in vitro angiogenesis assays demonstrated the strong inhibitory effect of Cabo-NPs on cell migration and tube formation. Furthermore, the Cabo-NPs exerted superior anti-angiogenic effects with remarkable reductions in the neovascular area, which were as effective as the clinical dexamethasone but without apparent side effects. The therapeutic mechanism of the Cabo-NPs is closely related to the significant decrease in proangiogenic and proinflammatory factors, suppressing neovascularization and inflammation. Overall, cationic Cabo-NPs offer a new prospect for safe and effective CNV treatment via enhancing the bioavailability of lipophilic cabozantinib.

Three novel variants identified within ECM-related genes in Chinese Han keratoconus patients

As the primary indication for corneal transplantation, the pathogenesis of keratoconus remains elusive. Aiming to identify whether any mutation from extracellular-matrix (ECM)-related genes contributes to the patients with sporadic cases of keratoconus (KC) from Chinese Han population, one hundred and fifty-three participants in total were enrolled in our study, including fifty-three KC patients and one hundred healthy controls. Mutational analysis of three ECM-related genes (LOX, COL5A1 and TIMP3) with next-generation sequencing and Sanger sequencing was performed. To further confirm the function of three ECM-related genes in the pathogenesis of keratoconus, we performed Real-time Quantitative PCR in vitro. Results showed that three new sequence variants (c.95 G > A in LOX, c.1372 C > T in COL5A1 and c.476 C > T in TIMP3) were identified in aforementioned ECM-related genes in KC patients without being detected among the healthy controls. According to the results of QPCR, we found that the expression levels of LOX and TIMP3 were decreased in the KC patients, while COL5A1 showed no significant difference of expression. This is the first time to screen so many ECM-related genes in Chinese keratoconus patients using next-generation sequencing. We find numerous underlying causal variants, enlarging lots of mutation spectrums and thus providing new sites for other investigators to replicate and for further research.

Regional differences in the global burden of age-related macular degeneration

Background

Age-related Macular Degeneration (AMD) is the leading cause of blindness. This study aims to analyze regional differences on the global burden of AMD and help direct related policy making.

Methods

Disability-adjusted life years (DALY) data were collected from the Global Burden of Disease Study (GBD) 2017 to estimate the AMD burden. Mean education years, human development index (HDI) and Public Health Expenditure were extracted from the Human Development Report 2018, and latitude data were obtained from the Google Earth. These four factors were analyzed to see their importance in regional differences of AMD burden, using Kruskal-Wallis test, Dunn’s multiple comparisons test as well as regression analysis.

Results

Global age-standardized DALY rates have decreased since 2011. Based on the WHO region system, age-standardized DALY rates in African and Eastern Mediterranean region were significantly lower than those of other four regions. Linear regression analysis indicated that age-standardized DALY rates were inversely related to HDI and mean education years.

Conclusions

The age-standardized AMD burden had a decreasing tendency recently. Lower socioeconomic status and fewer education years were associated with higher AMD burden. The finding of this study may highlight the importance of national development and education on relieving AMD burden.

Morphologic features and surgically induced astigmatism of femtosecond laser versus manual clear corneal incisions

PURPOSE

To compare the morphologic features and surgically induced astigmatism (SIA) between laser and manual clear corneal incisions (CCIs) after femtosecond laser-assisted cataract surgery.

SETTING

Eye Center, 2nd Affiliated Hospital, Medical College of Zhejiang University, Hangzhou, China.

DESIGN

Prospective case series.

METHODS

Patients had femtosecond laser-assisted cataract surgery with a CCI created with the laser or manually after random allocation. The corrected distance visual acuity, corneal topography, and anterior segment optical coherence tomography were assessed at the 1-day, 1-week, 1-month, and 3-month follow-ups.

RESULTS

The laser CCI group comprised 45 eyes and the manual CCI group, 48 eyes. The SIA was significantly lower in the manual CCI group than the laser CCI group at all visits (P < .05). At the 1-day and 1-week follow-ups, the mean CCI thickness was significantly smaller in the manual CCI group (P < .05). In the laser CCI group, the perpendicular linear distance between the external wound opening and the corneal vertex central line was statistically shorter than in the manual CCI group (P < .05). At 3 months, the SIA was correlated with the perpendicular linear distance with a Pearson correlation coefficient of -0.341 (P = .001).

CONCLUSIONS

Femtosecond laser-created CCIs for cataract surgery caused more SIA than manually created CCIs, which could have resulted from inaccurate or uncertain corneal incision positioning of the femtosecond machine. Manual creation of CCIs is recommended in femtosecond laser-assisted cataract surgery until the locating system for the femtosecond laser incision is updated.

Lens capsule-related complications of femtosecond laser-assisted capsulotomy versus manual capsulorhexis for white cataracts

PURPOSE

Comparison of lens capsule-related complications resulting from femtosecond laser-assisted capsulotomy and manual capsulorhexis in patients with white cataracts.

SETTING

Eye Center, Second Affiliated Hospital, Zhejiang Medical School, Hangzhou, China.

DESIGN

Prospective consecutive nonrandomized comparative cohort study.

METHODS

Selected patients were divided into a femtosecond laser-assisted cataract surgery group (FLACS group) and a conventional phacoemulsification cataract surgery group (CPCS group). Each case was recorded as either a type I or type II white cataract. Here, type I was characterized by the presence of a liquefied cortex, whereas type II had a solid cortex. Five experienced phacoemulsification surgeons conducted all surgeries. Lens capsule-related events, including anterior capsule tears, posterior capsule ruptures (PCRs), incomplete capsulotomies, and irregular capsulorhexes were recorded; surgical parameters, postoperative visual acuities, and intraocular lens (IOL) decentrations were evaluated.

RESULTS

The study comprised 132 eyes of 132 patients (66 in each group). Anterior capsule tears were significantly more common in the CPCS group than the FLACS group (12.1% versus 0%). All 8 cases of anterior capsule tears were type I cases. Six FLACS cases developed incomplete capsulotomies, four of which were type I cases. The incidences of PCRs and vitreous loss were the same. Capsulotomy produced better circularity index and diameter stability than capsulorhexis. IOLs were better centered in the FLACS group than the CPCS group. The mean ultrasound power, absolute phaco time, effective phaco time, and postoperative visual acuities were similar in both groups.

CONCLUSIONS

Compared with CPCS, FLACS decreased the risk for anterior capsule tears in white cataracts, especially in type I cases. However, it did not reduce the incidence of PCR. Incomplete capsulotomy during FLACS could happen in white cataracts. Using FLACS on white cataracts enabled more precise capsulotomies and better-centered IOLs.

The impact of GJA8 SNPs on susceptibility to age-related cataract

The gap junction protein alpha 8 (GJA8) gene has been widely studied in human congenital cataracts. However, little is known about its relationship with age-related cataract (ARC). In this study, three GJA8-tagged single nucleotide polymorphisms related to an increased ARC risk were identified: rs2132397 for general ARC under both dominant and additive models; rs7541950 for general ARC under both recessive and additive models; and rs6657114 for cortical cataract under the recessive model. To uncover the underlying mechanisms, this study also sought to explore whether GJA8 is involved in the autophagy process in human lens epithelial cells. The results showed that GJA8 may participate in autophagy to maintain the intracellular environment, which may be a novel mechanism for cataract formation induced by GJA8. In conclusion, this study identified the genetic susceptibility of GJA8 polymorphisms on ARC and provides new clues for fully understanding the pathological mechanism of GJA8 variants in affecting lens opacity.

Ptosis induced by topical steroid eye drops: Two cases reports

RATIONALE

Ptosis is a rare complication of periocular steroid use. Studies report that local injections of steroids produce ptosis. We describe the first 2 cases of ptosis because of long-term treatment with topical steroid eye drops.

PATIENT CONCERNS

Two cases admitted to our hospital because of ptosis of their right eye after long-term treatment with topical steroid eye drops. Both of them had uncontrolled Posner-Schlossman syndrome.

DIAGNOSIS

Two cases were diagnosed as steroid-related ptosis.

INTERVENTIONS

Regulatory anti-inflammation therapy was prescribed for case 1, and after inflammation control, phacoemulsification was done for her. Six months after steroid withdrawal, the levator resection of the right eye was performed. Case 2 refused our advice of steroid reduction and ptosis surgery.

OUTCOMES

After surgery, case 1 retained a symmetrical appearance during a 1-year follow-up. In the surgery, we found thin levator muscles and slack levator palpebrae superioris aponeurosis (LPSA) in the affected eye. Postoperative transmission electron microscopy revealed typical signs of apoptosis in levator muscle cells.

LESSONS

We suggest topical application of steroids induces levator muscle apoptosis and LPSA weakness, and results in ptosis.

Identification of seven novel ZNF469 mutations in keratoconus patients in a Han Chinese population

PURPOSE

To test for the potential presence of novel mutations in the zinc finger protein (ZNF469) gene in patients with sporadic keratoconus (KC) from a Han Chinese population.

METHODS

Fifty-three patients with primary KC, 30 patients with high myopia (HM), and 100 unrelated population-matched healthy controls without any ocular or systemic disorders, all of Han Chinese ethnicity, were recruited. Blood samples were donated, and genomic DNA was isolated from peripheral blood leukocytes. Sequence variations in ZNF469 were initially identified in patients with KC with next-generation sequencing and subsequently confirmed using Sanger sequencing. Sequence variants identified in patients with KC were subsequently screened in 30 patients with HM and 100 healthy control subjects. Other genes that were reported to be related to KC were also screened in the patients with KC who carried the mutations in ZNF469. The Sorting Intolerant Form Tolerant (SIFT) program was used to predict the effect of amino acid substitution on the ZNF469 protein.

RESULTS

Sixteen sequence variants in the coding regions of ZNF469 were identified in this Chinese KC cohort. After five known single nucleotide polymorphisms (SNPs), one false-positive result, and three mutations that were also detected in the results of the whole-exome sequencing (WES) data performed in 220 Han Chinese individuals without ocular abnormalities were removed, seven novel mutations in ZNF469 (c.2059G>A, c.2137C>A, c.3466G>A, c.3749C>T, c.4300G>A, c.4684G>A, and c.7262G>A) that were predicted to be potentially damaging were identified. The patient with KC with the c.3466G>A mutation was also shown to carry one dedicator of cytokinesis 9 (DOCK9) mutation (c.1940C>T). None of the mutations were detected in the patients with HM or the healthy controls. All of the seven mutations in the patients with KC were heterozygote.

CONCLUSIONS

The results suggested for the first time that ZNF469 has a pathogenic role in Chinese patients with KC and have widened the mutation spectrum of KC in the Han Chinese population.

Identification and Functional Analysis of a Novel MIP Gene Mutation Associated with Congenital Cataract in a Chinese Family

Congenital cataracts are major cause of visual impairment and blindness in children and previous studies have shown about 1/3 of non-syndromic congenital cataracts are inherited. Major intrinsic protein of the lens (MIP), also known as AQP0, plays a critical role in transparency and development of the lens. To date, more than 10 mutations in MIP have been linked to hereditary cataracts in humans. In this study, we investigated the genetic and functional defects underlying a four-generation Chinese family affected with congenital progressive cortical punctate cataract. Mutation screening of the candidate genes revealed a missense mutation at position 448 (c.448G>C) of MIP, which resulted in the substitution of a conserved aspartic acid with histidine at codon 150 (p.D150H). By linkage and haplotype analysis, we obtained positive multipoint logarithm of odds (LOD) scores at microsatellite markers D12S1632 (Z_max = 1.804 at α = 1.000) and D12S1691 (Z_max = 1.806 at α = 1.000), which flanked the candidate locus. The prediction results of PolyPhen-2 and SIFT indicated that the p.D150H mutation was likely to damage to the structure and function of AQP0. The wild type and p.D150H mutant AQP0 were expressed in HeLa cells separately and the immunofluorescence results showed that the WT-AQP0 distributed at the plasma membrane and in cytoplasm, while AQP0-D150H failed to reach the plasma membrane and was mainly retained in the Golgi apparatus. Moreover, protein levels of AQP0-D150H were significantly lower than those of wide type AQP0 in membrane-enriched lysates when the HEK-293T cells were transfected with the same amount of wild type and mutant plasmids individually. Taken together, our data suggest the p.D150H mutation is a novel disease-causing mutation in MIP, which leads to congenital progressive cortical punctate cataract by impairing the trafficking mechanism of AQP0.

The incidence of postoperative endophthalmitis after cataract surgery in China: a multicenter investigation of 2006-2011

AIMS

To estimate the cumulative incidence of postoperative endophthalmitis, identify risk factors and determine clinical outcomes in China.

METHODS

Medical records were reviewed for all patients with acute-onset endophthalmitis after cataract surgery from January 2006 to December 2011 at eight eye centres of tertiary care hospitals in China.

RESULTS

Sixty-six cases of presumed endophthalmitis occurred after 201 757 cataract surgeries, yielding a cumulative incidence of 0.033% (95% CI 0.025 to 0.041). Logistic regression analysis revealed that the risk of endophthalmitis increased with intraoperative communication with vitreous (multivariate OR 9.96; 95% CI 4.54 to 21.84; p<0.001). After a median follow-up of 153 days, best-corrected visual acuity in the affected eye was more than 20/70 in 29/65 (44.6%) patients, and more than 20/40 in 20/65 (30.8%). A predictor of good visual acuity was baseline acuity of counting fingers or better (OR 6.25; 95% CI 2.13 to 18.33). Of 64 cases, 25 (39.1%) were culture positive. Coagulase-negative Staphylococcus and Pseudomonas species were the most common organisms isolated, accounting for 72.0% of the culture-positive cases (18/25). Two eye centres that used a combination of a high concentration vancomycin (1 mg/0.1 mL intracameral vancomycin injection or 100 µg/mL vancomycin in irrigating solution) and tobramycin as infection prophylaxis achieved a lower incidence of endophthalmitis than other centres (p<0.001).

CONCLUSIONS

The incidence of acute postoperative endophthalmitis after cataract surgery in tertiary care hospitals of China was 0.033%. Intraoperative communication with vitreous was a major risk factor for developing endophthalmitis. Prophylactic use of a high-concentration vancomycin and tobramycin may play a positive role in the prevention of postoperative endophthalmitis after cataract surgery.

A recurrent PAX6 mutation is associated with aniridia and congenital progressive cataract in a Chinese family

PURPOSE

Aniridia is phenotyically and genetically heterogeneous. This study is to summarize the phenotypes and identify the genetic defect responsible for aniridia and congenital progressive cataract in a three generation Chinese family.

METHODS

A detailed family history and clinical data from patients were collected by ophthalmologic examination, including visual acuity, slit-lamp examination, tonometer, keratometry, corneal topography, optical coherence tomography, and ultrasonic A/B scan. All exons and flanking intronic sequences of the paired box 6 (PAX6) gene were amplified by polymerase chain reaction (PCR) and screened for mutation by direct DNA sequencing. Structure and function of the mutant PAX6 were analyzed by bioinformatics analysis.

RESULTS

All the six patients shared common manifestations of complete aniridia, congenital cataract and thickened cornea, and broad phenotypic variability was observed in nystagmus, ptosis, strabismus, glaucoma, corneal pannus, corneal curvature, corneal vascularization, cataract subtype, ectopia lentis, axial length, and optic disc anomalies. Sequencing of the candidate gene detected a heterozygous c.307C>T transition in the coding region of PAX6, resulting in the substitution of a highly conserved arginine codon for a termination codon (p.R103X). The p.P103X mutation co-segregated with the affected individuals in the family. The change was supposed to cause structural and functional changes based on computational analysis.

CONCLUSIONS

We identified a recurrent PAX6 c.307C>T mutation in an aniridia and congenital progressive cataract family, and summarized the variable phenotypes among the patients, which expanded the phenotypic spectrum of aniridia in a different ethnic background.

A novel GJA3 mutation associated with congenital nuclear pulverulent and posterior polar cataract in a Chinese family

Congenital cataract (CC) is the leading cause of visual disability in children. To date, mutations in many genes have been linked to CC. In a four-generation Chinese family with congenital nuclear pulverulent and posterior polar cataracts, we detected a heterozygous c.5G>A transition in the second exon of GJA3, resulting in the substitution of a highly conserved glycine with aspartic acid (p.G2D) at the N-terminus of the connexin46 (Cx46) protein. Wild type (wt) and mutant Cx46 plasmids were transfected into HeLa cells to examine the molecular basis of cataract formation. Unlike wt Cx46, Cx46G2D mutant formed gap junction plaques inefficiently, changed hemichannel permeability, and caused apoptosis. These results suggest that the glycine residue at the second position of the N-terminus is important for gap junction plaque formation and hemichannel function.

Closure of a persistent cyclodialysis cleft using the haptics of a normal-sized intraocular lens

A 50-year-old man suffering from hypotony in the right eye caused by a traumatic cyclodialysis and complicated by a choroidal detachment and cataract was treated in our clinic. After an unsuccessful direct cyclopexy, phacoemulsification was performed and a normal-sized single-piece polymethyl methacrylate posterior chamber intraocular lens (PMMA PCIOL) was inserted into the ciliary sulcus, with the haptic rotated toward the cyclodialysis cleft. Postoperatively, the corrected visual acuity improved to 20/20, and the intraocular pressure returned to normal. Ultrasound biomicroscopy showed the closure of the cleft. Phacoemulsification with a normal-sized PMMA PCIOL inserted into the ciliary sulcus is a safe, effective and technically simple surgical treatment for small cyclodialysis induced hypotony complicated by cataract. Internal compression of the cleft by the haptic of a normal sized IOL along with postoperative inflammation led to scarring and closure of the cleft.

The TGFBI R555W mutation induces a new granular corneal dystrophy type I phenotype

PURPOSE

To report the clinical and molecular features of a distinct form of transforming growth factor-β-induced (TGFBI) gene-linked corneal dystrophy exhibiting a new granular corneal dystrophy type I (CDGG1) phenotype.

METHODS

A complete ophthalmologic examination was performed in all individuals of a Chinese family in which autosomal dominant transmission of the disease had been observed. DNA was obtained from the peripheral blood leukocytes of each participating subject. Genetic analyses included keratin 3 (KRT3), keratin 12 (KRT12), and TGFBI polymerase chain reaction (PCR) amplification and automated nucleotide sequencing of exons from the genomic DNA.

RESULTS

The corneal phenotype in this pedigree was characterized by multiple bilateral dot-like, circular opacities at different corneal depths, with some of the affected individuals only having opacities in the epithelium, which is different from the typical CDGG1 phenotype. TGFBI analysis revealed a heterozygous point mutation at exon 12 (c.1663C>T) in all of the affected individuals, predicting a p.R555W missense mutation.

CONCLUSIONS

The phenotype which resulted from the TGFBI R555W mutation in this family is distinct from that observed in the typical case of CDGG1. We propose this disorder should be classified as a new phenotype of CDGG1, and this finding demonstrates the importance of gene diagnosis in the corneal dystrophies.

Characterization of a novel mutation in the CRYBB2 gene associated with autosomal dominant congenital posterior subcapsular cataract in a Chinese family

PURPOSE

To identify the underlying genetic defect in four generations of a Chinese family affected with bilateral congenital posterior subcapsular cataracts.

METHODS

Clinical data from patients in the family were recorded by slit-lamp photography. Genomic DNA samples were extracted from peripheral blood of the pedigree members. Mutation screening was performed in the candidate gene by bidirectional sequencing of the amplified products. The mutation was verified by restriction fragment length polymorphism (RFLP) analysis.

RESULTS

The congenital cataract phenotype of the pedigree was identified as posterior subcapsular by slit-lamp photography. Sequencing of the candidate genes detected a heterozygous c.5C→T change in the coding region of the βB2-crystallin gene (CRYBB2), resulting in the substitution of a highly conserved alanine to valine (p. A2V). All nine family members affected with cataracts were positive for this change, but it was not observed in any of the unaffected members of the family. The transition resulted in the loss of a HaeIII restriction site in the affected members of the pedigree, which was present in the unaffected family members and in all of the 100 unrelated individuals tested.

CONCLUSIONS

This study has identified a novel CRYBB2 gene mutation, resulting in the amino substitution p. A2V in a Chinese family with posterior subcapsular congenital cataracts. This mutation is probably the causative lesion for the observed phenotype in this family.

A Chinese family with progressive childhood cataracts and IVS3+1G>A CRYBA3/A1 mutations

PURPOSE

To characterize the disease-causing mutations in a Chinese family with progressive childhood cataracts.

METHODS

Family history and clinical data were recorded. Direct gene sequencing together with multi-point linkage analysis using microsatellite markers flanking the gene was applied to identify the disease-causing mutation.

RESULTS

Lens examination in the affected members revealed childhood cataracts along with progressive developing fetal nuclear lactescent cataracts with 'Y' sutural opacities, and also progressive developing peripheral cortical opacities. Direct gene sequencing showed a G>A transition at the donor splice site of intron 3 (IVS3+1 G>A) of the βA1/A3-crystallin gene (CRYBA3/A1) in this Chinese autosomal dominant childhood cataract family, and the maximum heterogeneity logarithm of odds (HLOD) score obtained by multi-point analysis was detected at marker locus D17S1800 (HLOD=3.005; α=1.000).

CONCLUSIONS

To our knowledge, this is the first report of a phenotype of progressive nuclear and cortical cataracts related to the CRYBA3/A1 mutation IVS3+1 G>A. This finding expands the spectrum of cataract phenotypes caused by the IVS3+1 G>A mutation of CRYBA3/A1, confirms the phenotypic heterogeneity of this mutation and suggests the mechanism that influences the cataractogenesis in different ethnic backgrounds.

A novel mutation in the major intrinsic protein (MIP) associated with autosomal dominant congenital cataracts in a Chinese family

PURPOSE

To detect the underlying genetic defect in a Chinese family affected with bilateral congenital cataracts.

METHODS

A detailed family history and clinical data were recorded. Mutation screening was performed in the nuclear cataract-related gene by bidirectional sequencing of the amplified products. The mutation was verified by denaturing high-performance liquid chromatography (DHPLC).

RESULTS

Two cataract phenotypes were observed within this family: one eye exhibited Y-suture and nuclear pulverulent opacification of the lens, while the others exhibited complete opacification in the fetal nuclear region. Sequencing of the candidate genes detected a heterozygous c.319G>A change in the coding region of the major intrinsic protein (MIP), resulting in the substitution of a highly conserved Valine by Isoleucine (p.V107I).The mutation was confirmed by DHPLC.

CONCLUSIONS

This study has identified a novel MIP mutation, p.V107I in a Chinese family with congenital cataracts. To the best of our knowledge, this is the first reported case of cataracts caused by a mutation in the second extracellular loop domain of MIP.

Identification of a novel splice-site mutation in MIP in a Chinese congenital cataract family

PURPOSE

To map the locus and identify the gene causing autosomal dominant congenital cataract (ADCC) with "snail-like" phenotype in a large Chinese family.

METHODS

Clinical and ophthalmologic examinations were conducted on family members and documented by slit lamp photography. Linkage analysis was performed with an initial 41 microsatellite markers, then 3 additional markers flanking the major intrinsic protein (MIP) gene. Mutations were screened by DNA sequencing and verified by restriction fragment length polymorphism (RFLP) analysis.

RESULTS

Significant two-point LOD scores were obtained at 5 markers flanking MIP with the highest 3.08 (theta=0.00) at marker D12S1632. Mutation screening of MIP identified a heterozygous G>A transition at the acceptor splice site of intron 3 (IVS3 -1 G>A), abolishing a BstSF I restriction site in one allele of all the affected individuals.

CONCLUSIONS

We identified a novel splice-site mutation (IVS3 -1 G>A in MIP) in a Chinese ADCC family. To our knowledge, this is the first report on an acceptor splice-site mutation in human genes associated with ADCC.

A nonsense mutation in CRYGC associated with autosomal dominant congenital nuclear cataract in a Chinese family

PURPOSE

To identify the genetic defect associated with autosomal dominant congenital nuclear cataract in a Chinese family.

METHODS

Family history and phenotypic data were recorded, and the phenotypes were documented by slit lamp photography. The genomic DNA was extracted from peripheral blood leukocytes. All the exons and flanking intronic sequences of CRYGC and CRYGD were amplified by polymerase chain reaction (PCR) and screened for mutation by direct DNA sequencing. Structural models of the wild type and mutant gammaC-crystallin were generated and analyzed by SWISS-MODEL.

RESULTS

Sequencing of the coding regions of CRYGC and CRYGD showed the presence of a heterozygous C>A transversion at c.327 of the coding sequence in exon 3 of CRYGC (c.327C>A), which results in the substitution of a wild type cysteine to a nonsense codon (C109X). One and a half Greek key motifs at the COOH-terminus were found to be absent in the structural model of the mutant truncated gammaC-crystallin.

CONCLUSIONS

A novel nonsense mutation in CRYGC was detected in a Chinese family with consistent autosomal dominant congenital nuclear cataract, providing clear evidence of a relationship between the genotype and the corresponding cataract phenotype.

Novel FBN1 mutations associated with predominant ectopia lentis and marfanoid habitus in Chinese patients

PURPOSE

To identify mutations in the fibrillin-1 gene (FBN1) and provide further information about genotype-phenotype correlations in Chinese patients with predominant ectopia lentis (EL) and marfanoid habitus.

METHODS

Patients from seven Chinese families underwent complete physical, ophthalmic, and cardiovascular examination. Genomic DNA was extracted from leukocytes of peripheral blood from the patients. The 65 exons and flanking intronic sequences of FBN1 were amplified by polymerase chain reaction (PCR) and screened for mutation by direct DNA sequencing.

RESULTS

Three novel mutations, c.203G>T in exon 2, c.502T>C in exon 5, and c.2096G>C in exon 16 as well as four known mutations, c.364C>T in exon 4, c.1633C>T in exon 13, c.1879C>T in exon 15, and c.4588C>T in exon37, were identified in FBN1.

CONCLUSIONS

We identified three novel mutations and four known mutations in FBN1 and found cysteine substitution highly related to EL. These results expand the mutation spectrum in FBN1 and enrich our knowledge of genotype-phenotype correlations due to FBN1 mutations. To our knowledge, this is the first report of cysteine residue loss in the unique NH2-terminal domain of fibrillin-1.

Progressive polymorphic congenital cataract caused by a CRYBB2 mutation in a Chinese family

PURPOSE

To report and identify the genetic defect that causes progressive polymorphic congenital cataracts affecting a large five generation Chinese family.

METHODS

Family history and phenotypic data were recorded, and the phenotypes were documented by slit lamp photography. Genetic linkage analysis was performed on the known genetic loci for autosomal dominant congenital cataract (ADCC) with 41 short tandem repeat polymorphic markers. Mutations were screened by DNA sequencing and restriction fragment length analysis (RFLP).

RESULTS

A significant two point LOD score was generated at marker D22S420, D22S539 and D22S315 for 22q11.2. The highest observed LOD score was 6.26 (theta=0.00) with marker D22S315. Mutation screening of the CRYBB2 gene in this family revealed an C-->T transition at position 475 (Q155X) of the cDNA sequence, creating a novel SpeI restriction site that cosegregated with affected members of the pedigree, but was not present in unaffected members or any of the 100 unrelated individuals tested.

CONCLUSIONS

Our finding expands the spectrum of cataract phenotypes caused by the Q155X mutation of CRYBB2, confirms the phenotypic heterogeneity of this mutation and suggests the mechanism that influences the congenital cataract formation in different ethnic backgrounds.

Special fasciculiform cataract caused by a mutation in the gammaD-crystallin gene

PURPOSE

To identify ultrastructure changes and genetic defects associated with a special fasciculiform autosomal dominant congenital cataract (ADCC) affecting a large Chinese family.

METHODS

Members of the Chinese family affected by this special fasciculiform ADCC were studied. Clinical examinations, light and transmission electron microscopy of the removed lens tissue, linkage analyses using polymorphisms of microsatellite markers, and mutational analyses of candidate genes by direct sequencing were performed.

RESULTS

The thirteen affected individuals in the family showed no variability between one another. The lens fiber cells showed focal degeneration, dense globular intracellular deposits, and an enlarged intercellular space. This ADCC was associated with a locus on chromosome 2q33-35 (maximum lod score [Zmax]=3.34; theta=0.05). Mutational analyses of the candidate genes (gamma-crystallin; CRYG), identified a C->A heterozygous transversion at nucleotide position 70 in the gammaD-crystallin gene (CRYGD) exon2, which co-segregated with the presence of ADCCs and was not observed in 100 unrelated controls.

CONCLUSIONS

This study identified ultrastructure changes and genetic defects associated with a special fasciculiform ADCC affecting a large Chinese family. It appeared to be caused by a missense mutation in the CRYGD gene, further supporting the notion that alterations to CRYG play an important factor in human cataract formation.

Caspase-3 and its inhibitor Ac-DEVD-CHO in rat lens epithelial cell apoptosis induced by hydrogen in vitro

OBJECTIVE

To investigate the role of caspase-3 and its inhibitor Ac-DEVD-CHO in rat lens epithelial cell apoptosis induced by hydrogen peroxide (H(2)O(2)) in vitro.

METHODS

Rat lenses were incubated in modified Eagle's medium containing 2 mmol/L H(2)O(2) to induce apoptosis in vitro. Apoptosis in lens epithelial cells was assessed by transmission electron microscopy and annexin V-propidium iodide (PI) double staining flow cytometry after 12, 24 and 48 h of incubation. The activity of caspase-3 was analyzed by western blotting.

RESULTS

Observations under transmission electron microscopy revealed that 2 mmol/L H(2)O(2) could effectively induce lens epithelial cell apoptosis in vitro. Caspase-3 activity increased during cell apoptosis and the peak measurement occurred at 24 h after treatment with H(2)O(2). Cell apoptosis was blocked by caspase-3 inhibitor Ac-DEVD-CHO.

CONCLUSIONS

The activation of caspase-3 plays an important role in executing apoptosis in H(2)O(2)-treated lens epithelial cells and in the formation of cataract. The caspase-3 inhibitor Ac-DEVD-CHO may effectively prevent lens epithelial cell apoptosis caused by oxidative injury.

[Influence of low molecular weight heparin on proliferation of bovine lens epithelial cells on the surface of intraocular lens]

OBJECTIVE

To investigate the anti-proliferation effect of low molecular weight heparin (LMWH) on bovine lens epithelial cells (BLEC) on the surface of polymethylmethacrylate (PMMA) intraocular lens (IOL).

METHODS

BLECs were incubated in vitro on the surface of PMMA IOLs. The cultural media contained LMWH (1 x 10(5) U/L) or normal heparin (1 x 10(5) U/L) or none of them (control). Cells were counted by flow cytometry.

RESULTS

The heparin or LMWH treated BLECs on the surface of PMMA IOLs showed immature appearance, while the BLECs in the control group showed a tendency of fibrosis. The numbers of BLECs (per ml) in the digested solution from the surface of IOLs were 878.2 +/- 107.8 (control), 545.5 +/- 58.2 (heparin) and 407.8 +/- 36.6 (LMWH). The comparisons among the three groups showed significant differences (P < 0.001).

CONCLUSION

Low molecular weight heparin inhibits proliferation of lens epithelial cells on the surface of intraocular lens, which could be used as a potential drug to prevent the occurrence of postoperative capsular opacification after IOL implantation.

[The expression of calpain II in rat lens epithelial cells of hydrogen peroxide-induced cataract]

OBJECTIVE

To study the expression and role of calpain II in rat lens epithelial cells (LECs) of hydrogen peroxide (H(2)O(2))-induced cataract.

METHODS

Rat lenses were cultured in vitro and cataract was induced by 2 mM H(2)O(2). The lenses were observed under microscope. Simultaneously, photographs and picture analyses were done in order to detect the variation of the opacity. The expression of calpain II in rat LECs was detected with immunohistochemical method and compared with a control group.

RESULTS

When the lenses were cultured in 2 mM H(2)O(2) for 3 hours (h), the expression of calpain II in rat LECs was increased obviously. There was significant difference between H(2)O(2)-induced and the control group (P = 0.006). After 6 h, vesicles appeared at the equator of the lenses. There was a significant difference between the result of picture analysis of H(2)O(2)-induced and control group (P = 0.013). So the expression of calpain II in rat LECs of H(2)O(2)-induced cataract was increased before cataract occurred. After induced with H(2)O(2) for 24 h, the opacity of lenses and the expression of LECs were both increased as compared with that at 6 h (P = 0.000, 0.000).

CONCLUSION

H(2)O(2) can enhance the expression of calpain II in rat LECs which may play a role in the mechanism of oxidative stress-induced cataract.

Phacofragmentation without perfluorocarbon liquid for dislocated crystalline lenses or lens fragments after phacoemulsification

PURPOSE

To evaluate the clinical outcome of vitrectomy with phacofragmentation without perfluorocarbon liquid (PFCL) in the management of dislocation of the crystalline lens, caused by trauma, hereditary disorders, or hypermature cataracts, and lens fragments due to phacoemulsification.

METHODS

A prospective study was conducted to evaluate 30 eyes of 29 patients who had undergone standard pars plana vitrectomy with phacofragmentation without PFCL in the vitreous cavity, for the removal of dislocated crystalline lenses or lens fragments, from January 1998 to July 2000. All cases were followed for more than six months.

RESULTS

Final best corrected visual acuity of 0.5 or better increased from 0% preoperatively to 36.7% postoperatively, and 0.2 or better rose to 76.7%. The mean IOP was significant reduced, from 26.35 mmHg to 12.75 mmHg. No intraoperative complications occurred. Although two eyes (6.7%) developed retinal detachment, one (3.3%) had cystoid macular edema (CME) and one (3.3%) had a transient intraocular pressure increase (to 25 mmHg) postoperatively, all others had a favorable outcome.

CONCLUSIONS

Standard pars plana vitrectomy with phacofragmentation without PFCL in the vitreous cavity is a safe, simple, and effective method for removing a dislocated crystalline lens or lens fragments, with good visual outcome.

Expression and effect of basic fibroblast growth factor on human cataract lens epithelial cells

OBJECTIVE

To detect the expression of basic fibroblast growth factor (bFGF) in human ocular tissues, and to assess the effect of bFGF on the proliferation of human cataract lens epithelial cells (LECs) and its correlation with age.

METHODS

Enucleated eyes were subjected to immunostaining for bFGF protein. Human cataract LECs were cultured in vitro, and treated with bFGF for 48 hr. Proliferation was estimated by the positive area ratio of proliferating cell nuclear antigen (PCNA) in immunohistochemistry.

RESULTS

bFGF protein was found in various human ocular tissues. bFGF stimulated human cataract LEC proliferation, and there was an age-related decrease in responsiveness of human cataract LECs to bFGF (P < 0.05).

CONCLUSION

bFGF might play an important role in the proliferation of residual human cataract LECs after cataract surgery.

[The comparison of two methods to predict the post-operative visual acuity of cataractous patients]

OBJECTIVE

To study the accurate methods to predict the post-operative visual acuity of cataractous patients with different degrees of opaque lenses.

METHODS

Visual electrophysiological methods and retinometer were used to evaluate the visual function after phacoemulsification and intraocular lens implantation in 152 cases (152 eyes). The regressive analyses between the post-operative best corrected visual acuity (BCVA) and each of the following results: the pre-operative flash electroretinogram (F-ERG), flash visual evoked potentials (F-VEP) and potential visual acuity (PVA) were performed, respectively.

RESULTS

More obvious linear-relationship was shown between PVA and BCVA (r = 0.654) than that between the combination of b wave's amplitude of F-ERG with wave's amplitude of F-VEP and BCVA (r = 0.528) in the patients with partial opaque lenses. Obvious linear-relationship between the combination of the F-ERG with F-VEP values and BCVA (r = 0.487) and no obvious relationship between the potential visual acuity and BCVA (r = 0.049) were shown in the patients with near complete/complete opaque lenses.

CONCLUSION

Both visual electrophysiological and retinometric detection, especially the latter one, can predict the post-operative visual acuity of the patients with partial opaque lenses accurately. Visual electrophysiological detection can predict the post-operative visual acuity of cataractous patients with near complete/complete opaque lenses accurately but retinometric detection can not.

[The age-related effect of basic fibroblast growth factor on the proliferation of lens epithelial cells]

OBJECTIVE

To detect the age-related effect of basic fibroblast growth factor (bFGF) on the proliferation of human lens epithelial cells (HLECs) in patients with cataract and discuss the mechanism.

METHODS

Human lens anterior capsules with attached HLECs were cultured in vitro, treated with 10 microg/L bFGF for 48hr, and then the positive area ratio of proliferating cell nuclear antigen (PCNA) in immunohistochemistry was estimated. Immunohistochemical analysis of bFGF receptor was also carried out.

RESULTS

The bFGF could enhance the HLEC proliferation in patients with cataract at various ages. The enhancement of the proliferation and the expression of bFGF receptor protein were negatively correlated to the age of the patients with cataract (P < 0.01).

CONCLUSIONS

The basic fibroblast growth factor might play an important role in the formation of posterior capsular opacity (PCO) after cataract surgery. With the decrease in the patient's age, the enhancement of HLEC proliferation is increased, indicating that the fact is related to the high incidence of PCO in children.