Occurrence of Oxidative Stress and Premature Senescence in the Anterior Segment of Acute Primary Angle-Closure Eyes

Aging, Cellular Senescence, and Glaucoma

Aging is one of the most serious risk factors for glaucoma, and according to age-standardized prevalence, glaucoma is the second leading cause of legal blindness worldwide. Cellular senescence is a hallmark of aging that is defined by a stable exit from the cell cycle in response to cellular damage and stress. The potential mechanisms underlying glaucomatous cellular senescence include oxidative stress, DNA damage, mitochondrial dysfunction, defective autophagy/mitophagy, and epigenetic modifications. These phenotypes interact and generate a sufficiently stable network to maintain the cell senescent state. Senescent trabecular meshwork (TM) cells, retinal ganglion cells (RGCs) and vascular endothelial cells reportedly accumulate with age and stress and may contribute to glaucoma pathologies. Therapies targeting the suppression or elimination of senescent cells have been found to ameliorate RGC death and improve vision in glaucoma models, suggesting the pivotal role of cellular senescence in the pathophysiology of glaucoma. In this review, we explore the biological links between aging and glaucoma, specifically delving into cellular senescence. Moreover, we summarize the current data on cellular senescence in key target cells associated with the development and clinical phenotypes of glaucoma. Finally, we discuss the therapeutic potential of targeting cellular senescence for the management of glaucoma.

Evaluation of Multimodal Biometric Parameters for Diagnosing Acute Angle Closure Secondary to Lens Subluxation

INTRODUCTION

To evaluate the clinical characteristics and multimodal biometric parameters from ultrasound biomicroscopy (UBM) and IOL Master biometry of patients with acute secondary angle-closure due to lens subluxation (ASAC-LS), acute primary angle-closure (APAC), and cataract.

METHODS

This retrospective study included 22 eyes with ASAC-LS, 27 eyes with APAC, and 39 eyes with cataract. Gender, age, affected eye, best corrected visual acuity, axial length, central corneal thickness, and anterior chamber depth (ACD) assessed by UBM and IOL Master were measured and compared between the three groups. In addition, we compared the ratio of ACD (ACD ratio) and the difference of ACD (ACD difference) measured by the two instruments. Logistic regression analysis was conducted to evaluate the predictive factors for lens subluxation. Receiver operating characteristic (ROC) curves were plotted to obtain a suitable cutoff value of biometric parameters to separate ASAC-LS cases from APAC and cataract cases.

RESULTS

In the ASAC-LS group, the median (interquartile range [IQR]) ACD measured by IOL Master was 2.47 (IQR 1.85-2.92) mm while the median ACD measured by UBM was 3.11 (IQR 2.60-3.76) mm. The difference of ACD measured by the two instruments was statistically significant in the ASAC-LS group (P < 0.001) whereas the differences were not statistically significant in the APAC group (P = 0.521) and cataract group (P = 0.204). Subsequent pairwise comparison revealed that only the ACD difference (0.40 [IQR 0.22-1.08] mm) and ACD ratio (1.18 [IQR 1.07-1.40]) in the ASAC-LS group were significantly different from those in the APAC group (ACD difference 0.02 [IQR 0.01-0.07] mm; ACD ratio 1.01 [IQR 1.00-1.04]) and cataract group (ACD difference 0.09 [IQR 0.01-0.14] mm; ACD ratio 1.03 [IQR 1.00-1.04]) (all P < 0.001). The ACD difference and ACD ratio were significantly associated with lens subluxation in the multivariate logistic regression analysis (P < 0.001 and P = 0.001, respectively). Additionally, the ROC curve analysis showed that the ACD difference at 0.235 mm and the ACD ratio at 1.080 were the respective cut-off values for lens subluxation, with a sensitivity of 77.3% and specificity of 100.0%.

CONCLUSION

Our findings provide a new option for identifying lens subluxation. Specifically, combining the ACD from UBM and IOL Master may be helpful for differential diagnosis of ASAC-LS.

Oxidative Stress-Induced Cellular Senescence in Aging Retina and Age-Related Macular Degeneration

Aging leads to a gradual decline of function in multiple organs. Cataract, glaucoma, diabetic retinopathy, and age-related macular degeneration (AMD) are age-related ocular diseases. Because their pathogenesis is unclear, it is challenging to combat age-related diseases. Cellular senescence is a cellular response characterized by cell cycle arrest. Cellular senescence is an important contributor to aging and age-related diseases through the alteration of cellular function and the secretion of senescence-associated secretory phenotypes. As a driver of stress-induced premature senescence, oxidative stress triggers cellular senescence and age-related diseases by inducing senescence markers via reactive oxygen species and mitochondrial dysfunction. In this review, we focused on the mechanism of oxidative stress-induced senescence in retinal cells and its role in the pathogenesis of AMD.