Do Levels of Stress Markers Influence the Retinal Nerve Fiber Layer Thickness in Young Adults?

Impact of Physiological and Psychological Stress on Glaucoma Development and Progression: A Narrative Review

Glaucoma is a leading cause of irreversible blindness worldwide. Presently, elevated intraocular pressure (IOP) is the only approved modifiable risk factor. A consensus of the current literature suggests that both physiological and psychological stress may also impact the lifelong course of glaucoma. Specifically, stress is known to influence sympathetic nervous system activity. An increase in sympathetic nervous system activity may elevate a person's blood pressure (BP) and IOP, and both are strongly associated with glaucomatous disease. Anxiety and depression have more conflicting evidence in relation to glaucoma. Socioeconomic and environmental stress may worsen adherence to therapy and disease outcomes due to a lack of financial resources and related access to healthcare. Neighborhood quality and environmental conditions, particularly urban environments, have been associated with glaucoma risk factors, higher glaucoma prevalence, and delayed surgical interventions. Racial differences have also been identified, with Black patients being more stressed and likely to present with increased glaucoma severity and faster disease progression than White patients. Mindfulness, meditation, and other forms of psychological relaxation have been shown to reduce IOP and stress biomarkers and result in improved quality of life (QOL). Larger studies in more diverse populations are needed to clarify risk and identify the best therapeutic approaches to reduce stress as a method to improve clinical outcomes and QOL for glaucoma patients.

Exploring the Impact of Blood Draws on the Intraocular Pressure of Older Adults: A Focus on Physiological Responses

Background/Objectives: This study investigated intraocular pressure (IOP) changes after a blood draw in older adults considering sex, age, and baseline IOP. Methods: Fifty-three subjects (54.7% females; age: 68.50 ± 4.46 years; Visual Function Index [VF14]: 94.50 ± 7.50 points; mean contrast sensitivity function (CSF) for both eyes in each spatial frequency [cdp]: 1.5 cdp [1.41 ± 0.20 log], 3 cdp [1.57 ± 0.29 log], 6 cdp [1.45 ± 0.39 log], 12 cdp [1.04 ± 0.40 log], 18 cdp [0.63 ± 0.31 log]) voluntarily participated. Subjects fasted for at least 8 h before attending the laboratory. First, IOP was measured in a seated position using a portable rebound tonometer. Ten minutes after the initial measurement, two 10 mL tubes of blood were drawn. Five minutes after the blood draw IOP was measured again following the same procedure as the initial measurement. We evaluated the differences using an analysis of variance. Results: Significant, but not clinically relevant, decreases were found in the right eye, with small effect sizes (p = 0.013-0.079, d = 0.35). Only males and subjects older than 68 years showed trends toward IOP reduction in the right eye. Subjects with baseline IOP ≥ 14 mmHg experienced significant IOP reductions in both eyes, with moderate effect sizes (p = 0.001-0.002, d = 0.56-0.69). Conclusions: Our findings suggest that a blood draw of 20 mL is safe for the IOP levels of older adults with baseline IOP between 11 and 21 mmHg. Variations in IOP were observed based on baseline IOP, sex, and age, suggesting the importance of personalized clinical assessments. The primary factor influencing IOP changes appears to be the baseline IOP level.

Exploring the Effects of Age at Menarche and Pregnancy on Myopia

PURPOSE

Associations between age at menarche and myopia have been observed in studies that included older women. Furthermore, pregnancy-related hormone surges in young women are associated with short-term changes in refractive error, although the long-term effects are less known. This study explored associations of age at menarche and parity with refractive error and ocular biometry in young women, and the relationship between age at menarche and refractive error in middle-aged adults for comparison.

METHODS

Community-based young women underwent eye examinations at 20 and 28 years old. Information on age at menarche and parity were collected prospectively. The older cohort underwent an eye examination and information on age at menarche was self-reported retrospectively. Cross-sectional associations between age at menarche and myopia were explored in both cohorts. Associations between parity and 8-year longitudinal change in refractive error measures were explored in the young cohort.

RESULTS

The cross-sectional analyses comprised 429 young (age 18-22) and 1,818 older (age 46-69) women. No associations were found between age at menarche and myopia or ocular biometry measures in either cohort. The longitudinal analysis (n = 269 women) revealed that for each pregnancy carried to full term, there rate of lens thickening increased by 0.004 mm/year (95% CI = 0.002-0.007). No other associations between parity and refractive error or ocular biometry were found.

CONCLUSION

There is no association between age at menarche and myopia or its related measures. While pregnancy was associated with thicker lens in the long term, there is no lasting effect on refractive error.

Stress, Allostatic Load, and Neuroinflammation: Implications for Racial and Socioeconomic Health Disparities in Glaucoma

Glaucoma is the leading cause of irreversible blindness, and its pathophysiology includes neuroinflammatory changes. The present therapies for glaucoma target pressure-lowering mechanisms with limited success, making neuroinflammation a target for future interventions. This review summarizes the neuroinflammatory pathways seen in glaucoma and their interplay with stress. Glucocorticoids have been shown to activate proinflammatory glial cells, contributing to the neuroinflammation in glaucoma. Glucocorticoids have also been shown to increase the IOP directly. Stress-associated autonomic dysfunction can affect the vascular homeostasis in the retina and create oxidative stress. Diabetes, hyperglycemic-mediated endothelial damage, and vascular inflammation also play important roles in the neuroinflammation in glaucoma and diabetic retinopathy. Psychosocial stress has been implicated in an increased IOP and glaucoma outcomes. People who experience maladaptive chronic stress suffer from a condition known as allostatic load, which describes pathologic neuroendocrine dysregulation. The effects of allostatic load and chronic stress have been studied in patients affected by a lower socioeconomic status (SES) and marginalized racial identities. A lower SES is associated with higher rates of glaucoma and also affects the access to care and screening. Additionally, people of African ancestry are disproportionately affected by glaucoma for reasons that are multifactorial. In conclusion, this review explores neuroinflammation in glaucoma, highlighting opportunities for future investigation.

Childhood Social Isolation as a Predictor of Retinal Neuronal Thickness in Middle Age: A Lifecourse Birth Cohort Study

OBJECTIVE

We investigated whether childhood social isolation was associated with retinal neural layer changes in adulthood, and whether this association was independent of other childhood or adulthood risk factors, including adult social isolation.

METHODS

Participants were members of the Dunedin Multidisciplinary Health and Development Study, a longitudinal population-based birth cohort from Aotearoa New Zealand ( n = 1037), born 1972 to 1973 and followed until age 45 years, with 94% of the living cohort still participating. Social isolation was recorded prospectively at ages 5, 7, 9, and 11 years, from teacher and parent report. Retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer thicknesses were measured via optical coherence tomography at age 45 years.

RESULTS

Childhood social isolation was associated with thinner average RNFL ( B = -0.739, p = .02), nasal RNFL ( B = -1.118, p = .005), and inferior RNFL ( B = -1.524, p = .007), although only nasal RNFL remained significant after adjustment. These associations were not fully explained by other psychosocial or physical health risk factors in childhood or adulthood, nor were they mediated by adult loneliness or social support.

CONCLUSIONS

Childhood social isolation was an independent predictor of RNFL thickness in middle age. Highlighting prospective links between childhood psychosocial adversity and retinal neuronal measures will help to inform future research into the utility of retinal neuronal thickness as a biomarker for neurodegeneration.

Protein Biomarkers in Glaucoma: A Review

Glaucoma is a multifactorial disease. Early diagnosis of this disease can support treatment and reduce the effects of pathophysiological processes. A significant problem in the diagnosis of glaucoma is limited access to the tested material. Therefore, intensive research is underway to develop biomarkers for fast, noninvasive, and reliable testing. Biomarkers indicated in the formation of glaucoma include chemical compounds from different chemical groups, such as proteins, sugars, and lipids. This review summarizes our knowledge about protein and/or their protein-like derived biomarkers used for glaucoma diagnosis since 2000. The described possibilities resulting from a biomarker search may contribute to identifying a group of compounds strongly correlated with glaucoma development. Such a find would be of great importance in the diagnosis and treatment of this disorder, as current screening techniques have low sensitivity and are unable to diagnose early primary open-angle glaucoma.

Physical Activity and Cardiovascular Fitness During Childhood and Adolescence: Association With Retinal Nerve Fibre Layer Thickness in Young Adulthood

PRECIS

Higher physical working capacity (PWC) at age 17 was associated with thicker peripapillary retinal nerve fiber layer (pRNFL) at age 20, suggesting a mechanistic link between cardiovascular fitness and neuroretinal integrity.

PURPOSE

Physical activity and cardiovascular fitness have been linked with lower odds of developing glaucoma. We tested the hypothesis that early beneficial effects of physical activity and cardiovascular fitness can be observed by measuring the pRNFL thickness in young healthy adults.

METHODS

The Raine Study is a longitudinal study that has followed a cohort since before their births in 1989-1992. Parent-reported physical activity was collected between 8 and 17 years, and latent class analysis was used to identify the participants' physical activity trajectories. At the 20-year follow-up (participants' mean age=20.1±0.4 y), participants' metabolic equivalent of task-minutes/week was determined using self-reported physical activity data. Participants' PWC was assessed at the 14- and 17-year follow-ups to estimate their level of cardiovascular fitness. An eye examination, which included spectral-domain optical coherence tomography imaging, was conducted at the 20-year follow-up for 1344 participants.

RESULTS

Parent-reported or participant-reported physical activity was not associated with pRNFL thickness. However, higher PWC at 17 years was associated with thicker pRNFL globally [by 0.3 µm; 95% confidence interval (CI)=0.2-0.6; P<0.001], superotemporally (by 0.4 µm; 95% CI=0.1-0.7; P=0.013), inferonasally (by 0.7 µm; 95% CI=0.1-0.9; P=0.002), and nasally (by 0.4 µm; 95% CI=0.1-0.7; P=0.006) per 10 Watt increase in PWC.

CONCLUSIONS

The association between estimated cardiovascular fitness and pRNFL thickness suggests there may be overlapping mechanisms for cardiovascular health and retinal ganglion cell integrity. While the effect sizes were small, it is possible that larger effects and clinically significant associations may arise as we follow this cohort of participants through their later adulthood.