Academic literature on the topic 'Cataract subtypes'

AbstractCataracts are mainly classified into three types: cortical cataracts, nuclear cataracts, and posterior subcapsular cataracts. In addition, retrodots and waterclefts are cataract subtypes that cause decreased visual function. To maintain an orderly and tightly packed arrangement to minimize light scattering, adhesion molecules such as connexins and aquaporin 0 (AQP0) are highly expressed in the lens. We hypothesized that some main and/or subcataract type(s) are correlated with adhesion molecule degradation. Lens samples were collected from cataract patients during cataract surgery, and mRNA and protein expression levels were measured by real-time RT-PCR and western blotting, respectively. The mRNA levels of adhesion molecules were not significantly different among any cataract types. Moreover, AQP0 and connexin 46 protein expressions were unchanged among patients. However, connexin 50 protein level was significantly decreased in the lens of patients with WC cataract subtype. P62 and LC3B proteins were detected in the WC patients’ lenses, but not in other patients’ lenses. These results suggest that more research is needed on the subtypes of cataracts besides the three major types of cataract for tailor-made cataract therapy.

Purpose Pterygium is an ocular surface disorder mainly caused by ultraviolet (UV) light exposure. This study explored the relationships between six cataract types with pterygium and UV exposure. Methods We have previously studied cataracts in residents of three regions in China and Taiwan with different UV intensities. From that study, we identified 1,547 subjects with information on the presence or absence of pterygium. Pterygium severity was graded by corneal progress rate. Cataracts were graded by classification systems as three main types (cortical, nuclear, posterior subcapsular) and three subtypes (retrodots, waterclefts, fiber folds) with high prevalence in middle-aged and elderly people. We calculated the cumulative ocular UV exposure (COUV) based on subject data and National Aeronautics and Space Administration data on UV intensities and used logistic regression to calculate odds ratios for the associations of COUV, cataract, and pterygium. Results We found an overall pterygium prevalence of 23.3%, with significant variation among the three regions. Four cataract types (cortical, nuclear, posterior subcapsular, and retrodots) were significantly associated with the presence of pterygium. Conclusions There was a significant association between COUV and pterygium, indicating that COUV is associated with the risk of pterygium development and that pterygium is useful as an index of UV exposure. Furthermore, the type of cataract in eyes with pterygium may indicate the level of UV exposure.

Even today, the leading cause of visual impairment is age related cataract. Among the risk factors for cataract, tobacco is one of the modifiable risk factors. Association between smoking and increased oxidative stress among cataract patients has been shown by some studies. But studies related to smokeless tobacco use are not done. The aim of the study was to estimate oxidative stress by markers like enzymatic antioxidant Superoxide Dismutase (SOD) and lipid peroxiation product Malondialdehyde (MDA) in tobacco user age related cataract (ARC) subjects and compare them with tobacco nonuser age related cataract (ARC) subjects. This cross sectional study was performed in 120 subjects divided into 2 groups – 60 tobacco nonuser age related cataract subjects and 60 tobacco user age related cataract subjects. 60 tobacco user cataract subjects divided into 5 groups - tobacco smokers, tobacco chewers, tobacco mishri users, dual tobacco chewers with mishri users and dual smokers with smokeless tobacco users. Oxidative stress was assessed by estimation of erythrocytic SOD and serum MDA. The study showed that in tobacco user group age of cataract patients was significantly less than tobacco nonuser cataract patients (P<0.05). Serum MDA levels were significantly high and erythrocytic SOD levels were significantly low in tobacco user cataract patients than tobacco nonuser cataract patients (P<0.001). Nuclear cataract was significantly more in tobacco user group (P<0.05). On comparison of subtypes of cataract in tobacco user subgroup, no significant difference was found. These results suggested that age related Cataract occurs at an earlier age in tobacco users due to increased oxidative stress. Also nuclear cataract was significantly associated with tobacco use.

Background: the safety and efficacy of cataract surgery in eyes with exudative neovascular age-related macular degeneration (nAMD), receiving active treatment, remain unclear. We evaluated the long-term outcomes and associated predictive factors of cataract surgery in eyes with exudative nAMD. Methods: this retrospective cohort study included 65 eyes (61 patients) treated with anti-vascular endothelial growth factor (VEGF) injections within six months preoperatively. Changes in best-corrected visual acuity (BCVA) and anti-VEGF treatment patterns from before to up to four years after surgery were assessed. Predictive factors were identified in association with one-year surgical outcomes. Results: the BCVA improved at six months (p < 0.001) and was maintained for three years postoperatively. The interval between anti-VEGF injections increased 3.4 times postoperatively (p = 0.001). Risk factors for poor BCVA were low preoperative BCVA (p < 0.001) and prolonged nAMD duration (p = 0.003). Prolonged nAMD duration and short exudation-free period were associated with more frequent postoperative anti-VEGF treatments (p = 0.028 and p = 0.003, respectively). AMD subtypes were not associated with both vision and injection pattern outcomes. Conclusions: patients with cataracts receiving nAMD treatment can safely undergo surgery with favorable long-term visual benefits. The preoperative BCVA, nAMD duration, and exudation-free period are potential predictors of surgery outcomes.

Purpose. Lanosterol synthase (LSS) abnormity contributes to lens opacity in rats, mice, dogs, and human congenital cataract development. This study examined whether LSS pathway has a role in different subtypes of age-related cataract (ARC). Methods. A total of 390 patients with ARC and 88 age-matched non-ARC patients were enrolled in this study. LSS expression was analyzed by western blot and enzyme-linked immunosorbent assay (ELISA). To further examine the function of LSS, we used U18666A, an LSS inhibitor in rat lens culture system. Results. In lens epithelial cells (LECs), LSS expression in LECs increased with opaque degree C II, while it decreased with opaque degree C IV and C V. While in the cortex of age-related cortical cataract (ARCC), LSS expression was negatively related to opaque degree, while lanosterol level was positively correlated to opaque degree. No obvious change in both LSS and lanosterol level was found in either LECs or the cortex of age-related nuclear cataract (ARNC) and age-related posterior subcapsular cataract (ARPSC). In vitro, inhibiting LSS activity induced rat lens opacity and lanosterol effectively delayed the occurrence of lens opacity. Conclusions. This study indicated that LSS and lanosterol were localized in the lens of human ARC, including ARCC, ARNC, and ARPSC. LSS and lanosterol level are only correlated with opaque degree of ARCC. Furthermore, activated LSS pathway in lens is protective for lens transparency in cortical cataract.

Magister Scientiae (Medical Bioscience) - MSc(MBS)
The present study describes molecular aspects of inherited congenital cataract in captive-bred Vervet monkeys. Congenital cataracts are lens opacities that are present at birth or soon after birth and include hereditary cataracts or cataracts caused by infectious agents. The MRC Primate Unit is housing a colony of captive-bred Vervet monkeys in which 7.5% is suffering from congenital cataract. However, the parents of the affected individuals were asymptomatic. Six families within the colony have been identified to be affected by two types of morphologies (Y-sutural and total cataract). Based on the evidence provided above, it was speculated that the colony was affected with autosomal recessive cataract. The main aim of this study was to facilitate a strategy for managing breeding programs by minimizing cataract occurrences in captive-bred Vervet monkeys. Integrated combination of clinical, molecular and bioinformatic strategies were used to identify and assess reciprocal candidate susceptibility genes for cataracts. The genes that are known to be responsible for most human congenital cataract cases were prioritized. The genes include Heat shock transcription factor 4 (HSF4), Crystalline Alpha A (CRYAA), glucosaminyl (N-acetyl) transferase 2 (GCNT2) and Lens intrinsic membrane protein 2 (LIM2). Twenty two subjects were selected based on their morphology (5 carriers, 5 controls and 12 cataracts). 2ml of blood was collected for Deoxyribonucleic acid (DNA) extraction. Coding exons and flanking regions were screened by polymerase chain reaction (PCR) amplification and sequenced. The CLC DNA workbench was used for results analysis. The screening of four genes revealed 20 sequence variants which were not present in the control individuals. Sequencing of HSF4 revealed three mutations: R116R, L245>L and P421>L in exon 5, 10 and 14, respectively. The coding exons for CRYAA showed two sequence variants: S134W and K166N in exon 3. Twelve mutations were identified in exon one of all three GCNT2 transcripts (A, B and C). These mutations include: G212G, H256>H, M258>V, N275>N, V16>I, Y122>F, S15>S, S24>N, S38>S, I118>I, D194>D and Y373>Y which was found in exon three of all transcripts. There were no mutations in LIM2, however, three single nucleotide polymorphisms (SNPs) were identified in exon 2 (P66>P) and 3 (I118>T and A127>T). The above mutations were conserved when aligned with other species. The sequence variations vary among the families and those individuals with the same or different cataract phenotype. Based on these findings, it can be concluded that the four candidate genes harbour mutations that are responsible for both phenotypes. The effect of these mutations in Vervet monkeys is not yet understood, however, their impact will be further investigated. For future studies, it will be of absolute importance to screen the entire family to verify that indeed cataract formation in this colony is inherited in an autosomal recessive manner.