Effect of examination stress on intraocular pressure in university students

Effects of Phenylcapsaicin on Intraocular and Ocular Perfusion Pressure During a 30-Min Cycling Task: A Placebo-Controlled, Triple-Blind, Balanced Crossover Study

The main objective of this placebo-controlled, triple-blind, balanced crossover study was to assess the acute effects of phenylcapsaicin (PC) intake (2.5 mg) on intraocular pressure (IOP), ocular perfusion pressure (OPP), and heart rate (HR) during a 30-min cycling task performed at 15% of the individual maximal power. Twenty-two healthy young adults performed the cycling task 45 min after ingesting PC or placebo. IOP was measured with a rebound tonometer before exercise, during cycling (every 6 min), and after 5 and 10 min of recovery. OPP was assessed before and after exercise. HR was monitored throughout the cycling task. We found an acute increase of IOP levels related to PC consumption while cycling (mean difference = 1.91 ± 2.24 mmHg; p = .007, ηp2=.30), whereas no differences were observed for OPP levels between the PC and placebo conditions (mean difference = 1.33 ± 8.70 mmHg; p = .608). Mean HR values were higher after PC in comparison with placebo intake (mean difference = 3.11 ± 15.87 bpm, p = .019, ηp2=.24), whereas maximum HR did not differ between both experimental conditions (p = .199). These findings suggest that PC intake before exercise should be avoided when reducing IOP levels is desired (e.g., glaucoma patients or those at risk). Future studies should determine the effects of different ergogenic aids on IOP and OPP levels with other exercise configurations and in the long term.

Increased incidence of acute primary angle closure during the COVID-19 outbreak in China: A retrospective analysis

This study aimed to investigate the incidence and clinical characteristics of acute primary angle closure (APAC) during the Coronavirus Disease 2019 (COVID-19) pandemic in China. This was a retrospective study of patients diagnosed with APAC in a glaucoma clinic over a 5-year period. We compared the number of APAC cases during the COVID-19 outbreak (December 7, 2022 to January 7, 2023) with those during the same period in previous years and 2 months prior to the outbreak. We also collected data on the demographic and clinical features of APAC patients, such as age, sex, disease course, visual acuity, intraocular pressure (IOP), and lens opacity. We included 95 eyes of 88 patients with APAC were included. Of these, 65 were female and 23 were male. The mean age was 68.0 ± 8.1 years. The median disease course was 10.8 ± 9.5 days. There was a significant increase in the number of APAC cases during the COVID-19 outbreak compared with the same months over a 5-year period (44 vs 51, P < .001). A higher proportion of women developed APAC during the outbreak period than during the non-outbreak period (P < .001). Eyes with APAC in the outbreak period had a lower mean IOP than those in the preceding 6 months (40.5 ± 8.8 mm Hg vs 46.1 ± 10.1 mm Hg; P = .043). No significant differences were observed in disease duration, lens opacity, or bilateral or unilateral onset between the 2 groups. Our study suggests a potential correlation between APAC and COVID-19, marked by a significant surge in APAC cases concurrent with the COVID-19 outbreak. However, the underlying mechanisms and preventive strategies remain to be elucidated.

Association Between Days of the Week and Intraocular Pressure: Japan Ningen Dock Study

PRCIS

The analysis of intraocular pressure (IOP) by day of the week using the mega database showed a periodic weekly pattern with the highest value on Monday.

PURPOSE

To evaluate IOP by the day of the week.

PATIENTS AND METHODS

Annual health checkup examinees between April 2014 and March 2015 were cross-sectionally evaluated. As a result, 655,818 participants [51.5±10.5 (range: 20-96) years, 40.1% women] from 103 medical centers were included. IOP was measured using a noncontact tonometer. The mean IOPs of each day of the week were compared using multiple comparison test and multiple linear regression analysis. Wednesday was set as the reference. Moreover, weekly IOP variations stratified by sex and age were also evaluated.

RESULTS

Mean IOPs from Monday to Sunday were 13.19±2.97, 13.06±2.92, 13.05±2.91, 13.05±2.92, 13.12±2.94, 13.10±2.96, and 13.16±2.78 mm Hg. IOP was significantly higher on Monday, Friday, and Saturday than those on Wednesday ( P <0.001, <0.001, 0.002). After adjusting for factors affecting IOP, the IOPs on Monday and Saturday were higher than those on Wednesday [β=0.097 (95% CI: 0.074-0.121), P <0.001; β=0.032 (95% CI: 0.005-0.059), P =0.019]. Men had significantly higher IOPs on Monday and Saturday than on Wednesday [β=0.142 (95% CI: 0.110-0.173), P <0.001; β=0.053 (95% CI: 0.017-0.089), P =0.004], whereas women did not have a significant trend. Participants aged below 65 years had higher IOPs on Monday ( P <0.001 in under 60 years; P =0.003 in 60-64 years), while those aged 65 years or older did not ( P =0.856).

CONCLUSION

IOP values may have a periodic weekly pattern. The high IOP on Monday was more pronounced in men aged less than 65 years.

Comparing the effects of intraocular pressure and tear production measurements in horses in two different environments: Horse stable and medical barn

BACKGROUND

To date, there are no studies on the impact of two distinct environments-one familiar to the horse and another unfamiliar-on intraocular pressure (IOP) and tear production.

OBJECTIVES

To compare the measured IOP and tear production values in horses between a horse stable and a medical barn.

STUDY DESIGN

Cross-over.

METHODS

Thirty healthy male Arabian horses, aged 6.88 ± 3.34 years were used. IOP and tear production measurements were assessed in both the horse stable and the medical barn, with a paired Student's t-test and Bland-Altman analysis conducted for comparison and agreement, respectively.

RESULTS

A significant increase in IOP was observed in the medical barn (34.2 ± 6.8 mmHg) compared with the horse stable (29.5 ± 7.2 mmHg, p = 0.02). However, no statistically significant difference in tear production was found between horse stable (22.1 ± 2.8 mm/min) and medical barn (23.6 ± 3.4 mm/min) (p = 0.09). The standard error of the slope was 0.36 for the IOP measured in the medical barn, indicating a difference of -4.7 mmHg compared with the IOP measured in the horse stable (p = 0.02). The bias was fitted to y = -7.9350 + 0.1003x. The standard error of the slope was 0.39 for the tear production measured in the medical barn, indicating a difference of -1.5 mm/min compared with the tear production measured in the horse stable (p = 0.09). The bias was fitted to y = 6.1530 + -0.3367x.

MAIN LIMITATIONS

The absence of horses with ocular disorders and an assessment of the potential impact of transportation.

CONCLUSIONS

A notable increase in IOP was observed in the medical barn compared with the horse stable, while tear production exhibited no significant variance between the two environments. The Bland-Altman analysis highlighted a discrepancy in IOP measurements in the horse stable, emphasising the potential influence of the environment on ocular parameters in horses.

Intraocular pressure fluctuations assessment in professional wind instrument players

CLINICAL RELEVANCE

Due to the long-time that wind musicians spend playing their instruments, it is important to investigate if intraocular pressure could be affected by this activity.

BACKGROUND

To assess the intraocular pressure fluctuations and fluctuations affecting factors in professional wind musicians while playing different tones.

METHODS

Thirty professional wind musicians (23.0 ± 3.20 years) were recruited from the Professional Music College of A Coruña. A questionnaire about environmental/demographic factors was given to participants. Intraocular pressure was measured four times by ICare IC100 tonometer: before, during low and high-pitched tones, and immediately after stopping playing the wind instrument.

RESULTS

Pairwise comparison revealed statistical differences between measurement points (Sidak, all p ≤ 0.019), except between before playing and while playing low-pitched tones (Sidak, p = 1.000). Intraocular pressure increases during high pitch playing and decreases after stopping playing. No significant differences in intraocular pressure fluctuation were reported between physically active (>2 days/week) and non-physically active participants (Unpaired t-test, p = 0.680). All intraocular pressure values were positively correlated (Pearson's correlation, all r ≥ 0.505, p ≤ 0.004). Intraocular pressure fluctuations were negatively correlated with musical playing years (Pearson's correlation, r = - 0.396, p = 0.030). There were no significant correlations among intraocular pressure fluctuation and gender, age, weight, height, or daily time playing (Pearson's correlation, all p ≥ 0.058).

CONCLUSION

Professional wind musicians suffer intraocular pressure peaks while playing high-pitched tones; therefore, ocular fundus evaluation and visual campimetry should be performed as routine tests in the visual exam of this population.

Psychiatric aspects of ophthalmic disorders: A narrative review

Ophthalmic disorders have psychiatric aspects associated with them at various levels. Psychological factors have a well-documented role in the causation, aggravation, and maintenance of various ophthalmic conditions, including glaucoma, central serous retinopathy, dry eye disease, and retinitis pigmentosa. Many ophthalmic conditions, including blindness, have psychological manifestations as well, which need to be addressed, in addition to the ophthalmic pathology. There is also significant overlap in the treatment of the two disciplines in many ways. For instance, many ophthalmic drugs have psychiatric side effects. Even ophthalmological surgeries have psychiatric aspects associated with them, which primarily include black patch psychosis and anxiety in the operation theater. This review will be useful for psychiatrists and ophthalmologists, for their clinical practice and research. Future research should focus on this interface to give it its well-deserved attention.

Diurnal Variation and Effects of Dilation and Sedation on Intraocular Pressure in Infant Rhesus Monkeys

PURPOSE

Intraocular pressure (IOP) is an important factor in numerous ocular conditions and research areas, including eye growth and myopia. In infant monkeys, IOP is typically measured under anesthesia. This study aimed to establish a method for awake IOP measurement in infant rhesus monkeys, determine diurnal variation, and assess the effects of dilation and sedation.

METHODS

Awake IOP (iCare TonoVet) was measured every 2 h from 7:30 am to 5:30 pm to assess potential diurnal variations in infant rhesus monkeys (age 3 weeks, n = 11). The following day, and every 2 weeks to age 15 weeks, IOP was measured under three conditions: (1) awake, (2) awake and dilated (tropicamide 0.5%), and (3) sedated (ketamine and acepromazine) and dilated. Intraclass correlation coefficient (ICC) was used to determine intersession repeatability, and repeated measures. ANOVA was used to determine effects of age and condition.

RESULTS

At age 3 weeks, mean (±SEM) awake IOP was 15.4 ± 0.6 and 15.2 ± 0.7 mmHg for right and left eyes, respectively (p=.59). The ICC between sessions was 0.63[-0.5 to 0.9], with a mean difference of 2.2 ± 0.3 mmHg. Diurnal IOP from 7:30 am to 5:30 pm showed no significant variation (p=.65). From 3 to 15 weeks of age, there was a significant effect of age (p=.01) and condition (p<.001). Across ages, IOP was 17.8 ± 0.7 mmHg while awake and undilated, 18.4 ± 0.2 mmHg awake and dilated, and 11.0 ± 0.3 mmHg after sedation and dilation.

CONCLUSIONS

Awake IOP measurement was feasible in young rhesus monkeys. No significant diurnal variations in IOP were observed between 7:30 am and 5:30 pm at age 3 weeks. In awake monkeys, IOP was slightly higher after mydriasis and considerably lower after sedation. Findings show that IOP under ketamine/acepromazine anesthesia is significantly different than awake IOP in young rhesus monkeys.

Clinical presentation of acute primary angle closure during the COVID-19 epidemic lockdown

Purpose

This study aimed to investigate the clinical presentation of acute primary angle closure (APAC) during the COVID-19 epidemic lockdown in Wuhan.

Methods

Consecutive patients seeking APAC treatment at the Wuhan Aier Eye Hospital during the 76 days (January 23-April 8, 2020) when the lockdown policy was implemented due to the COVID-19 pandemic were compared to those during the same period the following year (January 23-April 8, 2021), when the lockdown policy was not implemented. The cohorts were compared to assess demographic variables and clinical presentations.

Results

A total of 54 patients (64 eyes) were included in the 2020, compared with 46 patients (51 eyes) in the 2021. Demographic factors were similar between the groups. Significantly more patients developed blindness in the 2020 cohort (21.87%) than in the 2021 cohort (7.84%). Patients in the 2020 showed a longer time from symptom to treatment (241.84 ± 211.95 h in 2020 vs. 121.53 ± 96.12 h in 2021; P = 0.001), higher intraocular pressure at presentation (52.63 ± 12.45 mmHg in 2020 vs. 45.16 ± 9.79 mmHg in 2021; P = 0.001), larger pupil diameter (5.47 ± 1.62 mm in 2020 vs. 4.33 ± 1.27 mm in 2021; P = 0.001), and more glaucomatous optic neuropathy diagnoses [20/64 eyes (31.25%) in 2020 vs. 7/51 eyes (13.73%) in 2021; P = 0.03].

Conclusion

The time between the onset of APAC symptoms and its treatment during the COVID-19 epidemic lockdown was significantly prolonged, which increased the blindness rate of APAC patients.

Impact of fear of COVID-19 on students' performance, moderating role of mindfulness: HSK students' perception-based view

COVID-19 created difficulties and problems in almost everyone's daily life routine. Educational institutions too had to reschedule their academic activities. This shift caused attitudinal and behavioral changes in students' learning patterns. Using stress theory, the present study tries to determine the association of fear of COVID-19 with students' performance. In addition, the present study also attempts to check the impact of fear of COVID-19 on anxiety. Further, this study tries to find the association of anxiety with students' performance. This study also attempts to determine the mediating role of anxiety and the moderating role of mindfulness. For empirical investigation, the current study collected data from 320 HSK students from different colleges and universities in China. The present study applied partial least square structural equation modeling for the empirical investigation of hypotheses by using Smart-PLS software. The present study's findings confirmed that fear of COVID-19 negatively affects students' performance, and it positively correlates with anxiety. The study's outcomes revealed that anxiety negatively affects students' performance. The outcomes also confirmed that anxiety negatively mediates the relationship between fear of COVID-19 and students' performance. The present study's findings acknowledged that mindfulness does not moderate the relationship between fear of COVID-19 and student performance and has a positive moderation between anxiety and student performance. The present study offers important practical, theoretical, and managerial implications.

Intraocular pressure responses to a virtual reality shooting simulation in active-duty members of the Spanish Army: The influence of task complexity

Ocular physiology is sensitive to cognitively demanding tasks. However, it is unknown whether the intraocular pressure is also affected by the cognitive demands of military operations. The main objective was to determine the impact of a virtual reality shooting simulation with two levels of complexity on intraocular pressure levels in military personnel. Eighteen active-duty members of the Spanish Army and eighteen civilians performed two 4 min simulated shooting tasks with two levels of complexity using a virtual reality. In the "easy" task participants performed a simulated shoot when the stimulus (military with a rifle) appeared, while in the "difficult" task the stimulus randomly was a military with a rifle or with his hands on the air and participants were instructed to respond only when the military with a rifle appeared. Intraocular pressure was measured with a rebound tonometer before and immediately after each task. Complementarily, perceived levels of mental load and shooting performance (reaction time) were assessed. Intraocular pressure was greater after completing the more complex task in both military personnel (p-value < 0.01, Cohen´s d = 1.19) and civilians (p-value < 0.01, Cohen´s d = 1.16). Also, perceived levels of task load and reaction time were higher in the difficult compared to the easy shooting tasks (both p < 0.001). The rise in intraocular pressure is positively associated with the cognitive demands of simulated military operations. The potential application of this finding is the development of objective tools based on intraocular pressure for the evaluation of the mental state in real-world contexts, permitting to improve soldiers´ safety and performance.

Effects of water drinking on corneal biomechanics: The association with intraocular pressure changes

Purpose:

We aimed to assess the impact of drinking water (500 and 1000 mL) on corneal biomechanics and determine the level of association between changes in intraocular pressure and variations in the different biomechanical properties of the cornea.

Methods:

A total of 39 healthy young adults ingested either 1000 mL (n = 21) or 500 mL (n = 18) of tap water in 5 min. The CorVis ST system was used to assess corneal biomechanics at baseline and at 15, 30, and 45 min after water ingestion.

Results:

Water drinking induced statistically significant changes in the deformation amplitude (P < 0.001, η² = 0.166), highest concavity time (P = 0.012, η² = 0.093), peak distance (P < 0.001, η² = 0.171), time and velocity of the first applanation (P < 0.001, η² = 0.288 and P = 0.016, η² = 0.087, respectively), and time and velocity of the second applanation (P = 0.030, η² = 0.074 and P = 0.001, η² = 0.132, respectively), being independent of the amount of water ingested (P > 0.05 in all cases). There were significant associations between changes in intraocular pressure and some parameters of corneal biomechanics

Conclusion:

Small variations in whole-body hydration status alter different biomechanical properties of the cornea, with these changes being associated with intraocular pressure levels. These findings indicate that whole-body hydration status can be considered for the diagnosis and management of different ocular conditions.

Chronic social defeat stress causes retinal vascular dysfunction

PURPOSE

The roles of vascular dysfunction and chronic stress have been extensively discussed in the pathophysiology of glaucoma. Our aim was to test whether chronic stress causes retinal vascular dysfunction and therewith induces retinal ganglion cells (RGCs) loss.

METHODS

Twelve mice underwent chronic social defeat (CSD) stress, while 12 mice received control treatment only. Intraocular pressure (IOP) was measured with a rebound tonometer. Blood plasma corticosterone concentration and adrenal gland weight were used to assess stress levels. Brn-3a staining in retinas and PPD staining in optic nerve cross sections were conducted to assess the survival of RGCs and axons respectively. The ET-1 and α-SMA levels were determined in retina. Retinal vascular autoregulation, functional response to various vasoactive agents and vascular mechanics were measured using video microscopy.

RESULTS

No significant difference in IOP levels was observed during and after CSD between CSD mice and controls. CSD stress caused hypercortisolemia 2 days post-CSD. However, increased corticosterone levels went back to normal 8 months after CSD. CSD-exposed mice developed adrenal hyperplasia 3 days post-CSD, which was normalized by 8 months. RGC and axon survival were similar between CSD mice and controls. However, CSD stress caused irreversible, impaired autoregulation and vascular dysfunction of retinal arterioles in CSD mice. In addition, impaired maximal dilator capacity of retinal arterioles was observed 8 months post-CSD rather than 3 days post-CSD. Remarkably, ET-1 levels were increased 3 days post-CSD while α-SMA levels were decreased 8 months post-CSD.

CONCLUSIONS

We found that CSD stress does not cause IOP elevation, nor loss of RGCs and their axons. However, it strikingly causes irreversible impaired autoregulation and endothelial function in murine retinal arterioles. In addition, CSD changed vascular mechanics on a long-term basis. Increased ET-1 levels and loss of pericytes in retina vessels may involve in this process.

Repeatability, reproducibility, and agreement of three tonometers for measuring intraocular pressure in rabbits

The aim of this study was to evaluate repeatability, reproducibility, and agreement of three commonly used tonometers in animal research (TonoLab, TonoVet, and TonoPEN AVIA) in a cohort of 24 rabbits. Additionally, the impact of sedation on IOP was investigated in 21 New Zealand White rabbits with the TonoVet tonometer. Repeatability was determined using the coefficient of variation (CoV) for two observers. For the TonoLab (6.55%) and TonoVet (6.38%) the CoV was lower than for the TonoPEN AVIA (10.88%). The reproducibility was highest for the TonoVet (0.2 ± 3.3 mmHg), followed by the TonoLab (0 ± 12.89 mmHg) and lowest for the TonoPEN AVIA (− 1.48 ± 10.3 mmHg). The TonoLab and TonoVet showed the highest agreement (r = 0.85, R² = 0.73). After sedation, a significant IOP reduction (often > 25%) was observed. Our results show that among the three tonometers tested, the TonoVet tonometer is best for use in rabbits while the TonoLab should be avoided. The impact of sedation on IOP was substantial and should be taken into account during experimentation.

Changes in parameters of biochemical and oxidative stress in university students during and after examinations

The study aimed to evaluate the parameters of lipid peroxidation and antioxidant protection, biochemical parameters, and cortisol and adrenaline content in the blood of students depending on the effect of exam stress. A total of 135 healthy students (72 female (53.3%) and 63 male (46.7%)) aged from 19 to 21 years (mean age 20.16 ± 0.42 years) of the experimental group underwent detailed medical screening and examination before the inclusion in the study. The control group consisted of 30 healthy students (17 female (56.7%) and 13 male (43.3%)) of corresponding age (mean age 20.23 ± 0.54 years), whose medical examination was performed during breaks in the absence of any stress factors. The blood parameters of the experimental group were investigated 1 h before, 1 h after, and 24 h after the exam. The cortisol content in the blood of experimental group students significantly increased 1.37 times (p < 0.05) an hour before the exam and 1.32 times (p < 0.05) an hour after; adrenalin content in blood increased 1.76 times (p < 0.05) and 1.49 times (p < 0.05), respectively. Compared to the control group, intensification of lipid peroxidation processes with a 1.51-fold (p < 0.05) increase in erythrocyte malonic aldehyde content in blood 1 h before and 1.42-fold (p < 0.05) increase an hour after the exam was observed in students due to the effect of exam stress.. Changes in hormonal homeostasis, activation of lipoperoxidation processes with the development of oxidative stress, and the disintegration of antioxidant protection factors are typical for academic stress in students.

Effect of Electrical Stimulation of Cervical Sympathetic Ganglia on Intraocular Pressure Regulation According to Different Circadian Rhythms in Rats

Purpose

The purpose of this study was to investigate the relationship between circadian rhythm and intraocular pressure (IOP), and to explore whether electrical stimulation of cervical sympathetic ganglia (SCG) can regulate IOP via neurotransmitter distribution around the Schlemm's canal (SC) in rats.

Methods

Sprague Dawley rats were housed under normal (N-normal), constant dark (N-dark), and constant light (N-light) rhythms (n = 6 per group). Electrical stimulation (intermittent wave [20 hertz {Hz}, 2 mA, 10 minutes]) was used to stimulate the SCG. Atropine sulfate eye gel was applied three times a day. DiI was injected into the SCG and anterior chamber. The cross-sectional area and circumference of SC were evaluated using hematoxylin-eosin staining. Immunofluorescence staining was used to evaluate dopamine-β-hydroxylase (DβH) expression in SC endothelial (SCE) cells.

Results

N-Dark increased the IOP, decreased the cross-sectional area of SC, and increased DβH levels in SCE cells. Nerve projection between SC and SCG was detected, and electrical stimulation of SCG upregulated DβH expression in SCE cells. Under normal and constant light rhythms, electrical stimulation of SCG increased DβH and decreased the cross-sectional area and circumference of SC, while simultaneously increasing IOP and decreasing IOP fluctuations. After paralyzing the ciliary muscles, electrical stimulation of SCG decreased the cross-sectional area and circumference of SC under normal and constant light rhythms.

Conclusions

N-Dark increased DβH in SCE cells, reduced the cross-sectional area of SC, and increased IOP. Under the normal and light rhythms, electrical stimulation of SCG increased DβH in SCE cells, reduced the cross-sectional area and circumference of SC, and in turn elevated IOP and decreased IOP fluctuations.

Allostatic Load and Glaucoma: Are We Missing the Big Picture?

How to cite this article: Dada T, Mahalingam K, Gupta V. Allostatic Load and Glaucoma: Are We Missing the Big Picture? J Curr Glaucoma Pract 2020;14(2):47–49.

Can Psychologic Stress Elevate Intraocular Pressure in Healthy Individuals?

PURPOSE

To investigate if a stress event can influence intraocular pressure (IOP) in a group of healthy individuals.

DESIGN

Case-control study.

PARTICIPANTS

A total of 28 healthy subjects were included: 17 in the stress group and 11 in the control group.

METHODS

The Trier Social Stress Test (TSST) is a tool to evaluate cortisol response to psychologic stimulation based on the stress induced by public speaking. All participants underwent a modified diurnal tension curve (DTC) 1 week before the TSST, with 3 IOP measurements performed between 8:00 am and 2:00 pm. We evaluated the response to the TSST measuring the levels of salivary cortisol, IOP, and heart rate before, immediately after, and 40 minutes after TSST. The State Trait Anxiety Inventory (STAI) was applied to evaluate the levels of anxiety at the same time intervals.

MAIN OUTCOME MEASURES

Changes in IOP (mmHg), salivary cortisol, heart rate, and STAI scores.

RESULTS

At baseline, there were no significant differences between case and controls regarding age (52.2 ± 6.26 vs. 53.8 ± 8.4 years, P = 0.661), gender (52.94% male vs. 45.45% female, P = 0.669), and ethnicity. Salivary cortisol (6.8 nmol/l, P < 0.001) and heart rate (7.2 beats/min, P = 0.035) increased significantly after the TSST. We observed a mean IOP increase of 1.0 mmHg (right eye, P = 0.003) and 1.1 mmHg (left eye, P = 0.004) when comparing IOP measurements obtained during the DTC and immediately after TSST. In addition, 35% (6/17) of the subjects in the TSST group showed an IOP increase higher than 2 mmHg after the test compared with 18% (2/11) in the control group. The STAI state score significantly increased after the stress event compared with baseline (P = 0.026) and decreased from poststress to the recovery period (P = 0.006) in the TSST group. The control group did not show significant changes in IOP, heart rate, salivary cortisol levels, and STAI scores.

CONCLUSIONS

Significant elevations of IOP, salivary cortisol, STAI scores, and heart rate occurred after inducing psychologic stress with TSST in a group of healthy individuals.

The intraocular pressure responses to oral academic examination: The influence of perceived levels of public speaking anxiety

We examined the intraocular pressure responsiveness to oral examination stress, as well as the mediating role of the perceived levels of public speaking anxiety on intraocular pressure changes. Thirty-two university students (intervention group) publicly defended their degree final project, and intraocular pressure and perceived levels of stress were measured before and after the oral presentation, and after 10 min of recovery. The control group (n = 32) was not exposed to any stressful situation, and the dependent measures were taken at the same time points. All participants completed the public speaking anxiety scale. The intervention group exhibited higher intraocular pressure values before the oral presentation (corrected p-values<0.001), with these changes being positively associated with the perceived levels of public speaking anxiety (p < 0.001, r = 0.71). Our results reveal a mediating role of public speaking anxiety on the intraocular pressure responsiveness to oral examination stress, and highlight the utility of intraocular pressure as an indicator of stress in applied situations.

Intraocular Pressure as an Indicator of the Level of Induced Anxiety in Basketball

SIGNIFICANCE

Our data demonstrate that intraocular pressure (IOP) is sensitive to anxiety manipulation in sport scenarios, specifically in a basketball free throw task. The present outcomes may be of special relevance because of its practical advantages for the objective control of athletes' anxiety levels.

PURPOSE

Athletes experience high levels of anxiety during sport competition, and IOP has demonstrated to reflect autonomous nervous system changes during mentally demanding situations. We tested whether different levels of induced anxiety during basketball free throw shooting alter IOP.

METHODS

We followed a repeated-measures design to test the effects of anxiety-induced manipulation during basketball free throw shooting on IOP, shooting performance, and perceived anxiety. Eighteen amateur basketball players performed three experimental sessions consisting of 100 free throws each. However, we gave three different instructions to participants regarding the score assigned to each free throw, allowing us to manipulate the level of induced anxiety (low, medium, and high).

RESULTS

Confirming a successful anxiety manipulation, basketball players reported more perceived anxiety with higher levels of induced anxiety (P < .001, η = 0.37). Our data show that higher levels of induced anxiety provoke an acute IOP rise (P < .001, η = 0.44), with the low-, medium-, and high-anxiety-induced conditions promoting an average IOP rise of 0.21, 1.63, and 18.46%, respectively. Also, there was a linear IOP rise over time in the high-anxiety-induced condition (r = 0.82). Nevertheless, we found no effect of anxiety-induced manipulation on basketball free throw performance (P = .93).

CONCLUSIONS

Intraocular pressure is sensitive to anxiety-induced manipulation during basketball free throw shooting, showing an increase in parallel with accumulated anxiety. Based on these findings, IOP may be considered a promising tool for the assessment of the level of anxiety in certain sport situations. Future studies are required to explore the generalizability of these results in other scenarios with different physical and mental demands.

Association Between Arterial Blood Gas Variation and Intraocular Pressure in Healthy Subjects Exposed to Acute Short-Term Hypobaric Hypoxia

Purpose

To investigate the association between changes in arterial blood gases and intraocular pressure (IOP) after acute, short-term exposure to simulated elevation of 4000 m above sea level.

Methods

Twenty-five healthy young lowlanders participated in this prospective study. IOP was measured in both eyes with an Accupen tonometer. Arterial blood gas parameters (partial oxygen pressure [PaO₂], partial carbon dioxide pressure [PaCO₂], pH, and bicarbonate ion [HCO₃ ^-]) were checked using a blood gas analyzer. Measurements were taken at sea level (T1), at 15-minute (T2) and at 2-hour (T3) exposure times to simulated 4000 m above sea level in a hypobaric chamber, and upon return to sea level (T4). Associations between arterial blood gas parameters and IOP were evaluated using multivariate linear regression.

Results

PaO₂ significantly decreased at T2 and T3, resolving at T4 (P < 0.001). pH significantly increased at T2 and returned to baseline at T3 (P = 0.004). Actual and standard bicarbonate ion both dropped with IOP at T3 and T4. IOP significantly decreased from 16.4 ± 3.4 mm Hg at T1 to 15.1 ± 2.1 mm Hg (P = 0.041) at T3 and remained lower (14.9 ± 2.4 mm Hg; P = 0.029) at T4. IOP was not correlated with pH. Multivariate linear regression showed that lower IOP was associated with lower standard bicarbonate ion (beta = -1.061; 95% confidence interval, -0.049 to -2.074; P = 0.04) when adjusted for actual bicarbonate and diastolic blood pressure.

Conclusions

Hypobaric hypoxia triggers plasma bicarbonate ion reduction which, rather than pH, may decrease aqueous humor formation and subsequently cause IOP reduction. These findings may shed light on the mechanism of IOP regulation at high altitude.

Translational Relevance

Hypoxia-triggered reduction in plasma bicarbonate ion may decrease aqueous humor production, leading to IOP reduction at high altitude. These findings may provide new insight into a potential mechanism of IOP regulation. Hypobaric hypoxia at high altitude is an environmental factor that can reduce IOP and, therefore, deserves further study.

Effect of Anesthesia on Intraocular Pressure Measured With Continuous Wireless Telemetry in Nonhuman Primates

Purpose

To compare the effects of both injectable anesthesia (ketamine/dexmedetomidine versus ketamine/xylazine) and inhalant anesthesia (isoflurane) on IOP using continuous, bilateral IOP telemetry in nonhuman primates (NHP).

Methods

Bilateral IOP was recorded continuously using a proven implantable telemetry system in five different sessions at least 2 weeks apart in four male rhesus macaques under two conditions: ketamine (3 mg/kg) with dexmedetomidine (50 μg/kg) or ketamine with xylazine (0.5 mg/kg) for induction, both followed by isoflurane for maintenance. IOP transducers were calibrated via anterior chamber manometry. Bilateral IOP was averaged over 2 minutes after injectable anesthetic induction and again after isoflurane inhalant had stabilized the anesthetic plane, then compared to baseline IOP measurements acquired immediately prior to anesthesia (both before and after initial human contact).

Results

When compared to pre-contact baseline measurements, ketamine/dexmedetomidine injectable anesthesia lowers IOP by 1.5 mm Hg on average (P < 0.05), but IOP did not change with ketamine/xylazine anesthesia. IOP returned to baseline levels shortly after isoflurane gas anesthesia was initiated. However, injectable anesthesia lowered IOP by an average of 5.4 mm Hg when compared to that measured after initial human contact (P < 0.01).

Conclusions

Anesthetic effects on IOP are generally small when compared to precontact baseline but much larger when compared to IOP measures taken after human contact, indicating that IOP is temporarily elevated due to acute stress (similar to a "white coat effect") and then decreased with anesthetic relaxation. Anesthetic induction with ketamine/xylazine and maintenance with isoflurane gas should be used when IOP is measured postanesthesia.

Influence of holding weights of different magnitudes on intraocular pressure and anterior eye biometrics

PURPOSE

This study is aimed at determining the impact of holding weight corresponding to the 10% and 20% of participants' body weight during 5-min on intraocular pressure (IOP) and anterior eye biometrics.

METHODS

Eighteen healthy young adults grabbed two jugs with comfort-grip handles, which were filled with water in order to achieve the desirable load (10% and 20% of participants' body weight). A rebound tonometer and Oculus Pentacam were used to assess IOP and anterior segment biometrics, respectively, at baseline, after 0.5, 2, 3.5, and 5 min of holding weights, as well as after 0.5 and 2 min of recovery in each experimental condition (control, 10%, and 20%).

RESULTS

There was a significant effect of the load used on IOP (p = 0.016, ƞ_p² = 0.215) and anterior chamber angle (p = 0.018, ƞ_p² = 0.211), with the load corresponding to 20% of participants' body weight promoting a significant IOP rise (corrected p value = 0.035, d = 0.67), and anterior chamber angle reduction (corrected p value = 0.029, d = 0.69) in comparison with the control condition. No effects of holding weight were observed for anterior chamber depth and central corneal thickness (p > 0.348).

CONCLUSIONS

Our data evidence that holding weight during 5 min increases IOP and narrows the anterior chamber angle, being these effects significant when using a load corresponding to 20% of body weight. Based on the current outcomes, lifting or carrying heavy loads may be discouraged for glaucoma patients or individuals at high risk for glaucoma onset, although future studies should explore the clinical relevance of our findings.

The effects of topical dorzolamide 2% and brinzolamide 1%, either alone or combined with timolol 0.5%, on intraocular pressure, pupil diameter, and heart rate in healthy cats

Objective

To investigate the effects of topical dorzolamide 2% q8h and brinzolamide 1% q8h, administered either alone (A and B, respectively) or in combination with topical timolol 0.5% q12h (C and D, respectively), on the circadian pattern of intraocular pressure (IOP), the pupil size, and heart rate in healthy cats.

Methods

In this prospective, randomized, double‐blinded study, 10 healthy, adult cats were randomly assigned to one of four groups and the eye to be medicated was randomly assigned. IOP, pupil diameter, and heart rate were measured at 3‐hour intervals. A 5 days’ adjustment period was followed by a 5 days’ placebo (baseline) period. Then, all groups of cats received all four treatments (A‐D) according to a Latin square‐based rotating schedule. Five days’ medication periods were alternated with 3 days’ washout periods.

Results

Mean baseline IOP was 13.6 ± 2.7 mm Hg. All treatments resulted in a statistically significant decrease in mean IOP in the treated eye: A: −2.33 mm Hg (95% CI: −2.71, −1.94), B: −1.91 mm Hg (95% CI: −2.30, −1.53), C: −2.36 mm Hg (95% CI: −2.74, −1.97), and D: −2.37 mm Hg (95% CI: −2.76, −1.98) and the nontreated eye: A: −0.19 mm Hg (95% CI: −0.28, −0.11), B: −0.18 mm Hg (95% CI: −0.27, −0.10), C −0.31 mm Hg (95% CI: −0.40, −0.23), and D: −0.24 mm Hg (95% CI: −0.32, −0.15). Timolol resulted in an additional, significant decrease in IOP of 4% and 5%, respectively, compared to A and B, and in mild bradycardia and miosis.

Conclusions

Topical administration of dorzolamide 2% and brinzolamide 1% q8h significantly decreased IOP in healthy cats. Supplemental timolol 0.5% eye drops q12h resulted in an additional, statistically significant reduction of IOP.

Acute Stress Increases Intraocular Pressure in Nonhuman Primates

Purpose

To quantify intraocular pressure (IOP) change and time course during stressful activity.

Study Design

Experimental Study.

Subjects

Three nonhuman primates (NHPs).

Methods

Bilateral IOP and aortic blood pressure (BP) were recorded continuously, then averaged for periods of 8-30 seconds before, during, and after a common anesthetic induction procedure (cage squeeze followed by intramuscular injection). Experiments were repeated four times in each NHP.

Main Outcome Measures

IOP, BP, and heart rate (HR) change during an anesthetic induction procedure.

Results

IOP, mean arterial pressure (MAP), and HR increased rapidly and significantly by 27%, 38%, 34%, respectively, in anticipation of anesthetic induction (Figure; p<0.05). IOP rose ~10% within 10 seconds of hearing the technician enter the outer anteroom door, and reached its maximum within ~1 minute of first anticipating human contact. IOP fell to below baseline levels within 1 minute after anesthetic induction.

Conclusions

IOP increases rapidly and significantly in response to stressful situations in the nonhuman primate.

Acute emotional stress as a trigger for intraocular pressure elevation in Glaucoma

Background

Stress-induced activation of the sympathetic nervous system leads to a cascade of metabolic reactions. Emotional stress is a more specific form of stress in which the stressor is a psychological response to a situation subjectively perceived as traumatic. Stress hormones can have a wide range of effects on the body, however, it is still unclear if and how it can affect ophthalmic physiology. This report presents a case of severe ocular hypertension in which emotional stress was the only cause elicited, and explores potential aggravating factors.

Case presentation

A 78-year-old, personality type A, lady with a history of pseudo-exfoliative glaucoma presented with an acute asymmetrical raise in intraocular pressure (IOP) immediately following a family breakdown. Her IOP had previously remained stable following a deep sclerectomy in the right eye and an Ex-PRESS shunt in the left eye. Her examination was entirely normal otherwise, with a patent filtration and diffuse bleb as confirmed with anterior segment OCT imaging. Near-normalisation of her IOP was observed within 24 h, concomitantly with the reduction of her stress levels. No other cause for the transient acute hypertensive episode were found.

Conclusions

This case report suggests that acute emotional stress could severely affect IOP in patients suffering from glaucoma. This could be important when looking after glaucoma patients. It would also suggest that the personnality types, and the emotional and social context are more factors to take into account in glaucoma studies. These observations are based on a single case report and would need to be verified on a larger scale.

Intraocular pressure increases after complex simulated surgical procedures in residents: an experimental study

BACKGROUND

Surgeons' overload is one of the main causes of medical errors that might compromise patient safety. Due to the drawbacks of current options to monitor surgeons' load, new, sensitive, and objective indices of task (over)load need to be considered and tested. In non-health-care scenarios, intraocular pressure (IOP) has been proved to be an unbiased physiological index, sensitive to task complexity (one of the main variables related to overload), and time on task. In the present study, we assessed the effects of demanding and complex simulated surgical procedures on surgical and medical residents' IOP.

METHODS

Thirty-four surgical and medical residents and healthcare professionals took part in this study (the experimental group, N = 17, and the control group, N = 17, were matched for sex and age). The experimental group performed two simulated bronchoscopy procedures that differ in their levels of complexity. The control group mimicked the same hand-eye movements and posture of the experimental group to help control for the potential effects of time on task and re-measurement on IOP. We measured IOP before and after each procedure, surgical performance during procedures, and perceived task complexity.

RESULTS

IOP increased as consequence of performing the most complex procedure only in the experimental group. Consistently, residents performed worse and reported higher perceived task complexity for the more complex procedure.

CONCLUSIONS

Our data show, for the first time, that IOP is sensitive to residents' task load, and it could be used as a new index to easily and rapidly assess task (over)load in healthcare scenarios. An arousal-based explanation is given to describe IOP variations due to task complexity.