Intraocular pressure responses to systemic autonomic stimulation

Intraocular Pressure Changes in Non-Surgical Eyes of Patients Admitted for Glaucoma Surgery

(1) Background: In glaucoma patients, it is observed that intraocular pressure (IOP) in non-surgical eyes decreases during hospitalization, but detailed data have not been reported. This study aimed to examine changes in IOP in the non-surgical eyes of patients admitted for glaucoma surgery. (2) Methods: This retrospective study included 487 patients (254 males, 233 females). Statistical analysis was performed separately for groups that were and were not under medication treatment. (3) Results: In non-surgical eyes, the difference in IOP between admission and discharge was -1.6 ± 4.8 mmHg (95% confidence interval (CI), -2.1 to -1.2; p < 0.0001) with a significant decrease in the medication group (n = 414), while it was -0.6 ± 4.8 mmHg with no significant change observed (95% confidence interval (CI), -1.7 to 0.57; p = 0.33) in the non-medication group (n = 73). Multiple regression analysis of the medication group showed that IOP at admission (p < 0.0001) and older age (p = 0.03) were associated with the reduction or the rate of reduction in IOP. (4) Conclusions: IOP in the non-surgical eyes of patients admitted for glaucoma surgery with medication decreased during hospitalization. The reduction was more pronounced in individuals with higher IOP at admission and in older patients. It is possible that improved medication adherence contributes to the lowering of IOP.

Exploring the relationship between accommodation and intraocular pressure: a systematic literature review and meta-analysis

PURPOSE

To investigate the relationship between accommodation and intraocular pressure (IOP).

METHODS

Systematic literature search and meta-analysis following PRISMA guidelines was conducted on studies analyzing the relationship between accommodation and intraocular pressure. After removal of duplicates, title and abstract screening, full-text analysis was performed to select relevant articles and meta-analysis was then conducted as well.

RESULTS

Of the 1357 records identified, 17 met the selection criteria and were included. Overall, all studies showed that accommodation can influence IOP levels and meta-analysis indicated a significant IOP reduction of 1.10 mmHg (95%CI, -1.77; -0.42) following accommodative stimulus in healthy individuals, albeit with high heterogeneity among studies. Differences in IOP changes between emmetropic and progressing myopic individuals were not significant. Controversial results were obtained in patients with glaucoma with significantly lower IOP fluctuations being noted in eyes with previous trabeculectomy; however, the clinical heterogeneity of enrolled patients among studies made it not possible to combine results. Type of accommodative task, extraocular muscle contraction, head and body position all could potentially play a role in the measured IOP changes with, interestingly, near reading on a smartphone suggesting IOP increase.

CONCLUSION

Accommodation has an impact on IOP measurements and, overall, determines IOP decrease in healthy individuals. While such variations might not hold clinical significance for individuals in good health, their impact in patients with glaucoma should be considered. Further studies focused on specific components of such relationship are required to elucidate their individual impact and to define their potential role as non-pharmacological strategies to reduce IOP levels in selected patient categories.

Acute macular neuroretinopathy following Valsalva manoeuvre: an insight into the pathophysiology

Acute macular neuroretinopathy (AMN) affects the outer retina and is most likely induced by non-inflammatory ischaemia of the retinal deep capillary plexus and choriocapillaris. A man in his early 20s developed Valsalva retinopathy following weightlifting at the gym and presented with blurring of vision in the left eye 1 month after the initial retinal haemorrhages had resolved. A diffuse, purplish, donut-shaped, perifoveal lesion was seen on funduscopy and was well defined by an optical coherence tomography angiography (OCTA) en face image in the left eye. Outer retinal changes on optical coherence tomography (OCT) and a dense co-localised scotoma on a visual field (VF) examination confirmed the diagnosis of AMN, and the patient was started on a tapering dose of oral steroids. Improvement was seen in OCT, OCTA and VF during the 6-month follow-up visit. The use of OCTA en face imaging enabled the accurate identification of the lesion in the affected layers of the retina.

Acute Effects of Resistance Exercise on Intraocular Pressure in Healthy Adults: A Systematic Review

ABSTRACT

Hackett, DA, Li, J, Wang, B, Way, KL, Cross, T, and Tran, DL. Acute effects of resistance exercise on intraocular pressure in healthy adults: A systematic review. J Strength Cond Res 38(2): 394-404, 2024-Intraocular pressure (IOP) tends to fluctuate during a resistance exercise (RE). This systematic review examines the acute effects of RE on IOP in healthy adults and factors that influence changes in IOP. Five electronic databases were searched using terms related to RE and IOP. A strict inclusion criterion was applied, which included being 55 years or younger with no medical conditions and RE intensity needing to be quantifiable (e.g., based on a maximal effort). Thirty-four studies met the inclusion criteria for this review. Isometric and isotonic contractions produced similar changes in IOP during RE up to 28.7 mm Hg. Exercises that involved larger muscle mass, such as squats and leg press, were found to produce changes in IOP during exercise ranging from 3.1 to 28.7 mm Hg. Smaller changes in IOP during RE were found for exercises engaging less muscle mass (e.g., handgrip and bicep curls). Intraocular pressure was found to increase during RE when lifting heavier loads and with longer exercise durations (e.g., greater repetitions). The Valsalva maneuver (VM) and breath-hold during RE accentuated the change in IOP, with more extreme changes observed with the VM. However, most studies showed that postexercise IOP returned to baseline after approximately 1 minute of recovery. An acute increase in IOP is observed during RE in healthy adults with fluctuations of varying magnitude. Factors that independently increase IOP during RE include exercises involving larger muscle mass, heavy loads, greater set duration, and when the VM or breath-hold is performed.

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.

Sympathetic activation leads to Schlemm's canal expansion via increasing vasoactive intestinal polypeptide secretion from trabecular meshwork

We previously demonstrated vasoactive intestinal polypeptide (VIP) eyedrops reduce intraocular pressure (IOP) and stabilize cytoskeleton of the Schlemm's canal (SC) endothelium in a chronic ocular hypertension rat model. Here we determine if the trabecular meshwork (TM) releases endogenous VIP and affect SC in paracrine manner, and whether this cellular interaction via VIP is strengthened under stimulated sympathetic activity. A rat model of moderate-intensity exercise was established to stimulate sympathetic activation. IOP post exercise was measured by a rebound tonometer. Sympathetic nerve activity at the TM was immunofluorescence-stained with DβH and PGP9.5. Morphological changes of TM and SC were quantitatively measured by hematoxylin-eosin (HE) staining. Further, epinephrine was applied to mimic sympathetic excitation on primary rat TM cells, and ELISA to measure VIP levels in the medium. The cytoskeleton protective effect of VIP in the epinephrine-stimulated conditioned medium (Epi-CM) was evaluated in oxidative stressed human umbilical vein endothelial cells (HUVECs). Elevated sympathetic nerve activity was found at TM post exercise. Changes accompanying the sympathetic excitation included thinned TM, expanded SC and decreased IOP, which were consistent with epinephrine treatment. Epinephrine decreased TM cell size, enhanced VIP expression and release in the medium in vitro. Epi-CM restored linear F-actin and cell junction integrity in H₂O₂ treated HUVECs. Blockage of VIP receptor by PG99-465 attenuated the protective capability of Epi-CM. VIP expression was upregulated at TM and the inner wall of SC post exercise in vivo. PG99-465 significantly attenuated exercise-induced SC expansion and IOP reduction. Thus, the sympathetic activation promoted VIP release from TM cells and subsequently expanded SC via stabilizing cytoskeleton, which resulted in IOP reduction.

Intraocular pressure during handgrip exercise: The effect of posture and hypercapnia in young males

PURPOSE

As part of our investigations of intraocular pressure (IOP) as a potential contributing factor to the spaceflight-associated neuro-ocular syndrome using the 6° head-down tilt (6°HDT) bed rest experimental model, we compared the effect of rest and isometric exercise in prone and supine 6°HDT positions on IOP with that observed in the seated position.

METHODS

Ten male volunteers (age = 22.5 ± 3.1 yrs) participated in six interventions. All trials comprised a 10-min rest period, a 3-min isometric handgrip exercise at 30% of participant's maximum, and a 10-min recovery period. The trials were conducted under normocapnic (NCAP) or hypercapnic (FI CO2  = 0.01; HCAP) conditions, the latter mimicking the ambient conditions on the International Space Station. IOP, systolic and diastolic pressures, and heart rate (HR) were measured during the trials.

RESULTS

Isometric exercise-induced elevations in HR and mean arterial blood pressure. IOP in the prone 6°HDT position was significantly higher (p < 0.001) compared to IOP in supine 6°HDT position and seated trials at all time points. IOP increased with exercise only in a seated HCAP trial (p = 0.042). No difference was observed between trials in NCAP and HCAP. IOP in the prone 6°HDT position was constantly elevated above 21 mmHg, the lower limit for clinical ocular hypertension.

CONCLUSIONS

IOP in the prone 6°HDT position was similar to IOP reported in astronauts upon entering microgravity, potentially indicating that prone, rather than supine 6°HDT position might be a more suitable experimental analog for investigating the acute ocular changes that occur in microgravity.

Effects of isometric resistance exercise of the lower limbs on intraocular pressure and ocular perfusion pressure among healthy adults: A meta-analysis

BACKGROUND

The main risks for glaucoma are increased intraocular pressure (IOP) and decreased ocular perfusion pressure (OPP). This review aims to examine the potential impact of lower limb isometric resistance exercise on intraocular pressure and ocular perfusion pressure.

METHOD

A meta-analysis was conducted to determine the potential impact of isometric exercise on IOP and OPP. The literature on the relationship between isometric resistance exercise and IOP was systematically searched according to the "Cochrane Handbook" in the databases of Pubmed, Web of Science, EBSCO, and Scopus through December 31, 2020. The search terms used were "exercise," "train," "isometric," "intraocular pressure," and "ocular perfusion pressure," and the mean differences of the data were analyzed using the Stata 16.0 software, with a 95% confidence interval.

RESULTS

A total of 13 studies, which included 268 adult participants consisting of 162 men and 106 women, were selected. All the exercise programs that were included were isometric resistance exercises of the lower limbs with intervention times of 1min, 2min, or 6min. The increase in IOP after intervention was as follows: I²=87.1%, P=0.001 using random-effects model combined statistics, SMD=1.03 (0.48, 1.59), and the increase in OPP was as follows: I²=94.5%, P=0.001 using random-effects model combined statistics, SMD=2.94 (1.65, 4.22), with both results showing high heterogeneity.

CONCLUSION

As isometric exercise may cause an increase in IOP and OPP, therefore, people with glaucoma and related high risk should perform isometric exercise with caution.

Evaluation of Changes in Intraocular Pressure with a Noncontact Tonometer in Healthy Volunteers

Purpose

We investigated whether or not intrasession or intersession fluctuations in intraocular pressure occur in healthy people using a noncontact tonometer.

Materials and Methods

A noncontact tonometer was used to measure intraocular pressure in the bilateral eyes of healthy subjects for 5 consecutive days. Paired t-tests and one- and two-way repeated-measures analyses of variance were performed for the acquired data. A p-value <0.05 was considered to indicate statistical significance.

Results

Eighty eyes of 40 healthy subjects were enrolled in the study. On day 1, intraocular pressure was significantly higher in the right eye than in the left eye (P = 0.014). The one-way repeated-measures analysis of variance revealed that intraocular pressure in the left eye was significantly lower on day 1 than on days 2 to 5 (P = 0.000–0.018); however, there were no significant differences among intraocular pressures measured on days 1 to 5 in the right eye. The two-way repeated-measures analysis of variance revealed no significant difference in intraocular pressure between the right and left eyes (P = 0.913).

Conclusion

Although measurements using the noncontact tonometer were relatively stable, intraocular pressure was high on day 1.

Smartphones and vision

Many people spend too much time using their smartphones. Contrast, small screen size, resolution, image repetition frequency and screen reflection will cause characteristic ocular symptoms. The objective of this study is to describe the ophthalmological symptoms in persons who spend a large number of hours using electronic devices. For this purpose, a search was conducted in the Pubmed and MED line database to find the appropriate articles. The most frequent ocular manifestation after prolonged use of smartphones without care for eye hygiene were ocular complaints, such as tiredness, eye irritation, blurred vision and transient, but marked elevated intraocular pressure. Early and adequate recognition of ophthalmic symptoms that may be associated with the using smartphones for many hours and the implementation of appropriate management can protect against the occurrence of late complications in the form of permanent eye damage.

Effect of physical activity on severity of primary angle closure glaucoma

Objective:

To determine the association between physical activity and severity of primary angle closure glaucoma in Malay patients.

Methods:

A cross-sectional study was conducted involving 150 primary angle closure glaucoma patients between April 2014 and August 2016. Using the International Physical Activity Questionnaire, the physical activity status was assessed and divided into three categories: mild, moderate and heavy physical activity. The duration of physical activity and corresponding minimum energy requirements were calculated. Ocular examination was performed including Humphrey visual field 24-2 analysis assessment. Based on two consecutive reliable Humphrey visual fields, the severity of glaucoma was scored according to modified Advanced Glaucoma Intervention Study and classified as mild (0–5), moderate (6–11) and severe (12–20). Association between physical activity and Advanced Glaucoma Intervention Study score was determined with multiple linear regression analysis.

Results:

A total of 150 Malay patients with primary angle closure glaucoma were included (50 patients with mild, 50 with moderate and 50 with severe glaucoma). Physical activity showed inverse association with the severity of primary angle closure glaucoma. After calculating adjustments for age, sex, duration of glaucoma, body mass index, systemic co-morbidities, family history of glaucoma, myopia and educational status [adjusted b –3.41, 95% confidence interval (–5.23, –1.59), p < 0.001], there was also an inverse relationship with Advanced Glaucoma Intervention Study score. Every increase in physical activity level reduces the Advanced Glaucoma Intervention Study score by 3.4 point.

Conclusion:

Physical activity is the potential modifiable risk factor in reducing the severity of glaucoma among primary angle closure glaucoma patients. However, there is possibility of the severity of glaucoma restricted the physical activity of primary angle closure glaucoma patients.

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.

Intraocular pressure change during reading or writing on smartphone

Purpose

To investigate the effect of reading or writing on a smartphone in terms of intraocular pressure (IOP) changes.

Design

Prospective, comparative case series.

Participants

Thirty-nine (39) healthy young (age < 40) volunteers.

Methods

The participants were requested to conduct standardized work (i.e., read a sample text on single mobile device and subsequently type it on the same device) under daylight [300 lux] and low-light [100 lux] conditions independently on consecutive days. On each day, three sets of IOP measurements (total: 7) using a rebound tonometer (iCare PRO; Tiolat, Helsinki, Finland) were performed: (1) pre-work (baseline) [2 measurements], (2) during smartphone work [5, 15, and 25 minutes], and (3) post-work [5 and 15 minutes].

Main outcome measures

Changes in IOP at different check-out points.

Results

Under the daylight condition, the mean baseline IOP was 13.7 ± 1.8 mmHg, and the mean IOP increased after 5 minutes of work (14.1 ± 1.8 mmHg; +2.0 ± 1.9%; P < 0.001). When the smartphone work lasted for 15 minutes, the IOP showed a further significant increase (15.5 ± 1.7 mmHg; +12.9 ± 4.4%; P < 0.001), which persisted over the course of the 25 minutes of smartphone work (15.3 ± 1.8 mmHg; +11.1 ± 3.9%; P < 0.001); then, after stopping work for 5 minutes, the IOP was restored (13.9 ± 1.7 mmHg; +0.9 ± 2.1%; P = 0.220). Under the low-light condition, the mean IOP was significantly increased immediately after 5 minutes of smartphone work (from 13.9 ± 1.9 to 15.6 ± 1.8 mmHg; +12.1 ± 4.8%; P < 0.001); this IOP increase continued: 17.3 ± 1.9 [+24.7 ± 10.3%] at 15 minutes’ work, and 17.0 ± 1.7 mmHg [+23.1 ± 9.5%] at 25 minutes’ work (P < 0.001 at both check-out points). Five minutes after stopping the smartphone work, interestingly, the IOP significantly dropped, to a level even lower than that of the pre-work (12.8 ± 1.9 mmHg; -8.1 ± 3.0%; P < 0.001), and at post-work 15 minutes, the IOP returned to the baseline (13.9 ± 1.8 mmHg; -0.3 ± 2.6%; P = 0.360).

Conclusions

In healthy young subjects, reading or writing on smartphone significantly increased IOP, and the changes of IOP were faster and greater under the low-light condition. Smartphone users who are concerned about IOP fluctuation are advised to (1) take a break if they read or write on smartphone for more than 5 minutes, and (2) avoid using smartphones wherever possible in dark places.

Factors associated with fluctuations in repeated measurements of intraocular pressure using the Goldmann applanation tonometer in Japanese patients with primary open-angle glaucoma

Purpose

The aim of this study was to determine whether fluctuations in intraocular pressure (IOP) occur as a result of the order of IOP measurements or successive IOP measurements in patients with glaucoma and, if so, identify the factors causing these fluctuations.

Patients and methods

Four hundred twenty-eight eyes of 214 Japanese patients with primary open-angle glaucoma (POAG) were enrolled. Patients treated with beta-blockers or prostaglandin analogs alone were included. Additionally, in the IOP measurements by noncontact tonometer, the same cases of IOP of the right and left eyes prior to this study were included in this study. Four successive IOP measurements were carried out using a Goldmann applanation tonometer as follows: IOP was measured in the first eye (right or left) and then in the fellow eye and IOP was again measured in the first eye and then in the fellow eye. Repeated-measures analysis of variance was used to test the differences in IOP between successive measurements. Generalized linear mixed models were used to test differences in IOP measurements between the right and the left eyes on repeated applanation tonometry and according to the order of measurement. Conditional binomial logistic regression analysis was used to identify factors associated with fluctuating repeated applanation tonometry measurements. A P-value of <0.05 was considered statistically significant.

Results

IOP values decreased significantly according to the number of measurements (13.8–13.0; P<0.001–0.036, respectively). There was no significant difference in IOP measurements between the right and left eyes. The first IOP measurement was significantly higher than the fourth measurement (P=0.038); however, there was no significant difference between other combinations. The use of a prostaglandin analog was the only significant contributor to fluctuating IOP measurements (P=0.002).

Conclusion

IOP measured in the first eye, either right or left, was higher than that measured in the fellow eye in Japanese patients with POAG. The use of a prostaglandin analog may be associated with fluctuating IOP on repeated applanation tonometry.

Regulation of oxygen saturation in retinal blood vessels in response to dynamic exercise

PURPOSE

To evaluate the impact of dynamic exercise on retinal vessel oxygen saturation in healthy individuals.

METHODS

Twenty-six healthy participants underwent moderate dynamic exercise (modified Master's two-step exercise). In all subjects, intraocular pressures (IOP), systolic and diastolic blood pressures (SBP and DBP), retinal vessel calibres and retinal arterial and venous oxygen saturation were measured at baseline, immediately following exercise and 15 min postexercise.

RESULTS

Moderate dynamic exercise increased SBP and DBP immediately postexercise (SBP: 116 (±13) mmHg to 150 (±21) mmHg; p < 0.001 and DBP: 69 (±10) mmHg to 74 (±10); p < 0.001), while IOP decreased by an average of 2 mmHg (baseline: 13 (±3) mmHg)) immediately postexercise (11 (±2) mmHg). Oxygen saturation in retinal arteries remained unchanged (baseline = 93 ± 8%; immediately postexercise = 94 ± 9% and 15 min postexercise = 96 ± 8%; p = 0.069), but increased in retinal veins immediately postexercise and did not return to baseline values within 15 min postexercise (baseline = 54 ± 12%; immediately postexercise = 56 ± 15%; 15 min postexercise=57 ± 12%; p = 0.036).

CONCLUSION

There is a mild increase in retinal venous oxygen saturation and there is a trend towards an increase in arterial saturation in otherwise healthy individuals following dynamic exercise.

Effect of examination stress on intraocular pressure in university students

Intraocular pressure (IOP) has been investigated as a possible objective index of mental stressors. Here, we assessed the effect of examination stress on IOP in 33 university students. A repeated-measures design was used with two experimental conditions (examination and control) and two points of measurements (pre- and post-sessions). Also, the cardiovascular response, subjective perceived stress, as well as calculated ocular perfusion pressure and blood-pulse pressure were determined. A Bayesian statistical analysis showed higher IOP values in the examination in comparison to the control condition (BF₀₁ < 0.001). A similar pattern was found for the cardiovascular indices (diastolic and systolic blood pressure, and heart rate), and these findings were corroborated by subjective reports (BF₀₁ < 0.001 in all cases). Our data incorporates evidence in relation to the utility of IOP as an objective marker of examination stress, and it may help in the assessment and management of stress in applied scenarios.

Correlating Intraocular Pressure, Blood Pressure, and Heart Rate Changes after Jogging

Purpose

To examine the effects of jogging on intraocular pressure (IOP), blood pressure (BP), and heart rate (HR).

METHODS

Twenty-nine healthy individuals-25 athletes and 4 untrained-were studied. IOP, systolic and diastolic BP, and HR were measured before and just after 20 minutes of jogging (submaximal - 70% - aerobic exercise).

Results

IOP decreased after jogging. Only three individuals had unchanged IOP in one eye and one individual in both eyes. The IOP decrease (1 to 8 mmHg) was statistically significant (p<0.001). BP increased after jogging (systolic: 0 to 60 mmHg, statistically significant changes, p<0.001; diastolic: 0 to 15 mmHg, statistically significant changes, p<0.001). HR increased as well (15 to 80 pulses/min, statistically significant changes, p<0.001). However, there were individuals who presented a significant decrease of IOP and a mild BP rise and vice versa, and also individuals with mild IOP decrease and significant HR change and vice versa. The statistical analysis clearly showed that there are no linear quantitative correlations between BP or HR changes and IOP changes.

CONCLUSIONS

IOP decreases after jogging. Changes in BP and HR values have no linear quantitative correlation with IOP decrease.

Aerobic exercise and intraocular pressure in normotensive and glaucoma patients

BACKGROUND

With the increasing number of people participating in physical aerobic exercise, jogging in particular, we considered that it would be worth knowing if there are should be limits to the exercise with regard to the intraocular pressure (IOP) of the eyes. The purpose of this study is to check IOP in healthy and primary glaucoma patients after aerobic exercise.

METHODS

145 individuals were subdivided into seven groups: normotensives who exercised regularly (Group A); normotensives in whose right eye (RE) timolol maleate 0.5% (Group B), latanoprost 0.005% (Group C), or brimonidine tartrate 0.2% (Group D) was instilled; and primary glaucoma patients under monotherapy with beta-blockers (Group E), prostaglandin analogues (Group F) or combined antiglaucoma treatment (Group G) instilled in both eyes. The IOP of both eyes was measured before and after exercise.

RESULTS

A statistically significant decrease was found in IOP during jogging. The aerobic exercise reduces the IOP in those eyes where a b-blocker, a prostaglandin analogue or an alpha-agonist was previously instilled. The IOP is also decreased in glaucoma patients who are already under antiglaucoma treatment.

CONCLUSION

There is no ocular restriction for simple glaucoma patients in performing aerobic physical activity.

Effect of hospitalization on intraocular pressure in patients with high tension and normal tension glaucoma

PURPOSE

To determine the effect of hospitalization on intraocular pressure (IOP) in glaucoma patients.

DESIGN

Prospective case series.

METHODS

IOP was measured on three consecutive days in 26 high-tension (HTG) and 13 normal-tension (NTGwm) glaucoma patients under IOP-lowering treatment, and in 28 normal-tension glaucoma patients without IOP-lowering treatment (NTGnm), and change was compared by analysis of variance.

RESULTS

IOP decreased significantly, but comparably, in the three groups and between right and left eyes, although, the relative change to IOP on day 1 was significantly less pronounced in the group without treatment on day 2 and 3 compared with the treated groups.

CONCLUSIONS

Glaucoma patients showed a significant decrease in IOP during hospitalization. Although this decrease was more pronounced among the treated patients, it was also present in nontreated patients. Consequently, other factors than improved compliance during hospitalization must play a role in this phenomenon.

The effect of simulated obstructive apnoea on intraocular pressure and pulsatile ocular blood flow in healthy young adults

AIM

To investigate the effect of negative inspiratory effort, as generated by the Mueller manoeuvre, on intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) in healthy young adults.

METHODS

Seven volunteers with no history of systemic or ocular disease were recruited (mean age 30.7 years, range 25-40 years, M/F: 4/3). After initial instruction and practice of the Mueller manoeuvre, baseline measurements of IOP and POBF were obtained for both eyes after 10 and 15 minutes of rest, respectively, in the supine position. Thereafter, the Mueller manoeuvre was performed creating a mouthpiece pressure of -20 cm H(2)O, for at least 15 seconds followed by a 5 minute rest. The manoeuvre was repeated with a mouthpiece pressure of -40 cm H(2)O. IOP and POBF were measured 5-15 seconds into the manoeuvre for both -20 cm H(2)O (M2A) and -40 cm H(2)O (M4A) and directly upon recovery (after two respiratory cycles) from each manoeuvre (M2B, M4B). Baseline measurements were compared using paired t test, whereas manoeuvre induced changes in IOP and POBF were analysed individually using repeated measures ANOVA with Student-Newman Keuls post hoc analyses. Linear regression analysis was used to investigate a dose-response effect.

RESULTS

No significant differences were found between baseline measurements so they were subsequently pooled. There was a significant decrease in IOP for M2B (-9.2%, p<0.05), M4A (-13.8%, p<0.05), and M4B (-15.6%, p<0.05), relative to baseline. A dose-response relation was found for the effect of mouthpiece pressure on measurements 5-10 seconds into the manoeuvre (M2A and M4A, r = 0.54, p = 0.045). There was a trend of increased POBF relative to baseline for all measurements; however, significance was reached for M4B only (p = 0.039).

CONCLUSION

It was shown that forced inspiratory efforts as generated by the Mueller manoeuvre are associated with a dose dependent decrease in IOP and a concomitant increase in pulsatile ocular blood flow.

Attempted eyelid closure affects intraocular pressure measurement in open-angle glaucoma patients

PURPOSE

To evaluate the effect of attempted eyelid closure on intraocular pressure (IOP) measurements in normal-tension (NTG) and high-tension (HTG) open-angle glaucoma patients.

DESIGN

Prospective clinical trial.

METHODS

Forty randomly selected eyes of 40 patients underwent corneal pachymetry and IOP measurements using both Goldmann applanation tonometry and Tono-pen XL (Mentor, Inc., Norwell, Massachusetts, USA). Intraocular pressure was measured by the same examiner holding the eyelids open, both with and without the subject simultaneously attempting forced eyelid closure. Subjects were seated during all measurements and waited 5 minutes between measurements with each instrument; the order of measurement was randomized.

RESULTS

Twenty NTG and 20 HTG eyes were enrolled. The mean age was 63.0 +/- 13.0 years (range, 31-80 years). The average corneal thickness was 540 +/- 32 microm (range, 480-608 microm) in NTG patients and 552 +/- 40 microm (range, 449-610 microm) in HTG patients (P =.07, analysis of variance [ANOVA]). Using Goldmann applanation tonometry, IOP measurement in eyes with NTG increased by 3.9 +/- 2.0 mm Hg with attempted eyelid closure (P <.0001, paired t test; range, 2-11 mm Hg). With the Tono-pen XL, IOP measurements increased 4.2 +/- 2.7 mm Hg (P <.0001, paired t test; range, 1-14 mm Hg). With attempted forced eyelid closure, the Goldmann applanation measurement in eyes with HTG increased 4.1 +/- 2.1 mm Hg (P <.0001, paired t test; range, 1-9 mm Hg). Using the Tono-pen XL, measurements increased 4.5 +/- 2.0 mm Hg (P <.0001, paired t test; range, 2-11 mm Hg).

CONCLUSION

Attempted eyelid closure during tonometry is a significant and common source of error in eyes with glaucoma and may influence the clinical management and decision-making in the treatment of NTG and HTG.

Massive suprachoroidal hemorrhage during pars plana vitrectomy associated with Valsalva maneuver

PURPOSE

To report the intraoperative occurrence of massive intraocular suprachoroidal hemorrhage associated with Valsalva maneuver.

METHODS

Retrospective, multicenter study of patients who developed massive choroidal hemorrhage associated with Valsalva maneuver during vitrectomy.

RESULTS

Massive intraoperative suprachoroidal hemorrhage in seven patients (seven eyes) involved three men and four women with a median age of 52 years (range, 26 to 82 years). General anesthesia was used in six of seven cases. Coughing or "bucking" on the endotracheal tube during general anesthesia or severe coughing during the one vitrectomy performed under local anesthesia was associated with massive suprachoroidal hemorrhage. In five of seven eyes, this occurred near the end of surgery, after air-fluid exchange but before sclerotomy closure. Scleral plugs were immediately placed, and sclerotomy closure was performed exigently. Immediate posterior sclerotomy was performed on five of seven eyes; an additional patient underwent posterior sclerotomy postoperatively. After median follow-up of 18 months (range, 3 to 36 months), final visual acuity was no light perception in four eyes, light perception in one eye, 20/250 in one eye, and 20/20 in one eye. Four eyes became phthisical.

CONCLUSIONS

Valsalva maneuver during pars plana vitrectomy may result in massive suprachoroidal hemorrhage with disastrous visual consequences. Precautionary measures to prevent coughing or "bucking" on the endotracheal tube during general anesthesia, or a prolonged episode of coughing during local anesthesia, may prevent this potentially devastating complication.

Intraocular pressure changes: the influence of psychological stress and the Valsalva maneuver

The effects of psychological stress and the Valsalva maneuver on short-term variations of intraocular pressure (IOP) were studied in 49 healthy adults. Psychological stress consisted of mental arithmetic tasks presented in counterbalanced order by computer and by the experimenter. Additionally, a standardized Valsalva maneuver was performed (in counterbalanced order with the psychological stressors). IOP was measured with a Goldmann tonometer before and after performance of each stressor. All three stressors transiently and highly significantly increased IOP, although the Valsalva maneuver produced changes of a greater magnitude (10.2 mmHg) than the psychological stressors (1.3 mmHg). Subjective stress ratings and heart rate increased in response to all stressors. There were no effects of task sequence, eye muscle tension, sex, smoking status (some smokers misreported their smoking status), or regular marijuana use, but regular physical exercise was associated with less IOP increase during psychological stress.

Sources of error with use of Goldmann-type tonometers

There are many sources of error in the use of Goldmann-type applanation tonometers. In clinically normal corneas hypofluorescence of the precorneal tear film, accommodation, the Valsalva maneuver and vertical gaze are preventable causes of large tonometric errors. Repeated tonometry may induce a decline in the intraocular pressure (IOP). Variations in the corneal resistance to indentation between eyes cause significant errors. The most significant cause of error in clinically abnormal eyes is corneal epithelial edema, which causes a marked underestimation of IOP. Measurements obtained with Goldmann-type tonometers can be used with confidence to monitor changes in the IOP of an individual, but should not be relied on to determine the absolute manometric pressure within an eye or to compare the IOPs in eyes of different individuals.