Corneal nerve changes by anti-glaucoma medications examined by in vivo confocal microscopy.

AIM: To evaluate the effects of antiglaucoma eye drops on corneal nerves by in vivo confocal microscopy (IVCM). METHODS: This study comprised 79 patients diagnosed with glaucoma and 16 healthy control individuals. Among the glaucoma patients, 54 were treated with medication, while 25 remained untreated. Central corneal images were evaluated by IVCM, and then ACCMetrics was used to calculate the following parameters: corneal nerve fiber density (CNFD), branch density (CNBD), fiber length (CNFL), total branch density (CTBD), fiber area (CNFA), fiber width (CNFW), and fractal dimension (CNFrD). The correlation between IVCM parameters and drugs was evaluated using non-parametric measurements of Spearman's rank correlation coefficient. RESULTS: The CNFD was reduced in glaucoma groups compared to healthy subjects (P<0.01). Patients using anti-glaucoma medications exhibited poorer confocal parameters compared to untreated patients. As the number of medications and usage count increased, CNFD, CNBD, CNFL, CTBD, CNFA, and CNFrD experienced a decline, while CNFW increased (all P<0.01). For the brinzolamide-therapy group, there was a significant decrease in CNFD and CNFL compared to the other monotherapy groups (P<0.001). In the absence of medication, CNFD in males was lower than that in females (P<0.05). Among patients under medication therapy, CNFD remained consistent between males and females. CONCLUSION: Antiglaucoma eye drops affect the microstructure of corneal nerves. IVCM and ACCMetrics are useful tools that could be used to evaluate the corneal nerve changes.

Targeting mechanics-induced trabecular meshwork dysfunction through YAP-TGFß Ameliorates high myopia-induced ocular hypertension.

High myopia is a risk factor for primary open angle glaucoma (POAG). The pathological mechanism of high myopia induced POAG occurrence is not fully understood. In this study, we successfully established the guinea pig model of ocular hypertension with high myopia, and demonstrated the susceptibility of high myopia for the occurrence of microbead-induced glaucoma compared with non-myopia group and the effect of YAP/TGF-ß signaling pathway in TM pathogenesis induced by high myopia. Moreover, we performed stretching treatment on primary trabecular meshwork (TM) cells to simulate the mechanical environment of high myopia. It was found that stretching treatment disrupted the cytoskeleton, decreased phagocytic function, enhanced ECM remodeling, and promoted cell apoptosis. The experiments of mechanics-induced human TM cell lines appeared the similar trend. Mechanically, the differential expressed genes of TM cells caused by stretch treatment enriched YAP/TGF-ß signaling pathway. To inhibit YAP/TGF-ß signaling pathway effectively reversed mechanics-induced TM damage. Together, this study enriches mechanistic insights of high myopia induced POAG susceptibility and provides a potential target for the prevention of POAG with high myopia.

Assessment of iris volume in glaucoma patients with type 2 diabetes mellitus by AS-OCT.

AIM: To examine the change of iris volume measured by CASIA2 anterior segment optical coherence tomography (AS-OCT) in glaucoma patients with or without type 2 diabetes mellitus (T2DM) and explore if there is a correlation between hemoglobin A1c (HbA1c) level and iris volume. METHODS: In a cross-sectional study, 72 patients (115 eyes) were divided into two groups: primary open angle glaucoma (POAG) group (55 eyes) and primary angle-closure glaucoma (PACG) group (60 eyes). Patients in each group were separately classified into patients with or without T2DM. Iris volume and glycosylated HbA1c level were measured and analyzed. RESULTS: In the PACG group, diabetic patients' iris volume was significantly lower than those of non-diabetics (P=0.02), and there was a significant correlation between iris volume and HbA1c level in the PACG group (r=-0.26, P=0.04). However, diabetic POAG patients' iris volume was noticeably higher than those of non-diabetics (P=0.01), and there was a significant correlation between HbA1c level and iris volume (r=0.32, P=0.02). CONCLUSION: Diabetes mellitus impact iris volume size, as seen by increased iris volume in the POAG group and decreased iris volume in the PACG group. In addition, iris volume is significantly correlated with HbA1c level in glaucoma patients. These findings imply that T2DM may compromise iris ultrastructure in glaucoma patients.

Quantifying Nasotemporal Asymmetry of Interocular Suppression in Alternating Strabismus After Correction.

Purpose: This study identifies and characterizes the nasotemporal hemifield difference of interocular suppression in subjects who have been successfully treated for strabismus. Methods: Interocular suppression in the nasal and temporal hemifields were measured using two methods, namely, binocular phase combination and dichoptic motion coherence, both entailed suprathreshold stimuli. We tested 29 clinical subjects, who had strabismus (19 with exotropia and 10 with esotropia) but regained good ocular alignment (within 10 prism diopters) after surgical or refractive correction, and 10 control subjects. Results: Both the hemifield binocular phase combination and the hemifield dichoptic motion coherence tests revealed similar nasotemporal asymmetry of interocular suppression. Subjects with previous exotropia showed deeper suppression in the nasal hemifield, and those with previous esotropia showed deeper suppression in the temporal hemifield. This finding was consistent with the hemifield suppression theory. Furthermore, there was deeper suppression but less imbalance of nasotemporal asymmetry in the hemifield dichoptic motion coherence test. Finally, clinical stereopsis and the nasotemporal asymmetry of suppression (P < 0.05 in both tests) were negatively correlated in subjects with previous exotropia and measurable stereopsis. Conclusions: Hemifield asymmetry of interocular suppression in corrected strabismus can be measured by using static and dynamic suprathreshold stimuli. Thus, the evaluation of binocular vision in strabismus should focus on both the magnitude and the pattern of interocular suppression.