Changes In Ocular Pressure Research Articles

Systemic and ocular pressure changes following sympathetic activation in yoga practitioners - A comparative study

Introduction and Aim: Blood Pressure (BP), Intraocular Pressure (IOP) and Ocular Perfusion Pressure (OPP) are precursor parameters that lead to development of glaucoma. Under conditions of stress, either physical or psychological origin, there is disturbance of autonomic regulation. This causes increased activation of the sympathetic nervous system which might influence BP and ocular pressures. An altered autonomic balance towards lower sympathetic drive is observed in subjects practicing yoga, but it is not clear whether this adaptation also influences ocular pressures. Our study attempted to analyze variations in BP, IOP and OPP following sympathetic activation in yogic practitioners and non-practitioners of yoga. Materials and Methods: One hundred and ten subjects aged 18 - 25 years were recruited and categorised into yoga and non-yoga group. Basal BP was recorded using a sphygmomanometer and IOP was recorded using a rebound tonometer. Isometric hand grip (IHG) and Cold pressor test (CPT) were administered one at a time. IOP and BP were recorded immediately following these sympathetic activation tests. Mean arterial pressure and OPP was calculated using standard formula. Results: Significant increase in the values of pulse, BP, IOP and OPP following sympathetic activation were observed in the non-yoga group which was not noted in the yoga group. Elevation in systemic and ocular pressures following sympathetic activation was less in yoga practitioners. This adrenergic response was greater in the non-yoga group. Conclusion: Regular yoga practice maintains adequate perfusion of ocular tissues by autoregulation. Hence yoga can be recommended as a complementary health approach for the autonomic nervous system imbalance.

Study of Intra Ocular Pressure Changes after Isometric Handgrip Exercise Test in Young Adults

Objective: ToStudy the effect of isometric handgrip exercise test on Intra ocular pressure in young adultsMethod: Healthy young male adults in the age group of 18-22 years were selected among MBBS phaseI students of a Medical college .Sample size was 40. Heart rate and IOP were recorded at rest and afterisometric handgriptestResults: Right eye IOP has decreased significantly from resting 16.28±1.55 to 9.30±1.79( p<0.001)immediately after handgripexercise IOP Left eye IOP has decreased significantly from resting 16.15±1.69 to13.04±1.19 (p<0.001)immediately after handgrip exercise IOPConclusion: Isometric handgripexercise lowers IOP which were significant. Hence may prove useful innormotensive glaucomatous patients

Intra Ocular Pressure Changes in Soldiers during Military March

Background: Military activities cannot be classified as pure isometric or pure dynamic exercise. The effects of these activities on intra ocular pressure (IOP) have not been investigated so far. Objectives: The current study aimed to evaluate the short-term effects of military activities on IOP. Methods: Following a cross-sectional design, this study was conducted on 44 soldiers in the Islamic Republic of Iran Army. Soldiers’ heart rate and IOP were recorded before marching activities at rest, immediately after marching, and 30 minutes after the march. The measurements were repeated in the same process in 3 months. The marching activity was the same for all participants and took 60 minutes. Results: In total, 44 soldiers were studied, with a mean age of 21.80 ± 1.56 years. The IOP measurements before, immediately after, and 30 minutes after the marching were significantly different. IOP was significantly lower after the march (P < 0.001), and 30 minutes after the march, it was increasing gradually. The same results were observed in the IOP measurements 3 months later. We found no association between IOP after marching and heart rates before and after marching. Also, no significant association was observed between IOP and age. Conclusions: IOP was significantly decreased after marching, but it was transient. The results indicate that the dynamic component in military marches is more prominent than isometric parts.

Downregulation of Retinal Connexin 43 in GFAP-Expressing Cells Modifies Vasoreactivity Induced by Perfusion Ocular Pressure Changes.

PurposeGlia and their communication via connexin 43 (Cx43) gap junctions are known to mediate neurovascular coupling, a process driven by metabolic demand. However, it is unclear whether Cx43 mediated glial communication intermediates classical autoregulation. Here we used viral transfection and a glial fibrillary acidic protein (GFAP) promoter to downregulate glial Cx43 to evaluate its role in retinal vascular autoregulation to ocular perfusion pressure (OPP) reduction.MethodsAdult rats were intravitreally injected with the viral active construct or a control. Three weeks after the injection, eyes were imaged using confocal scanning laser ophthalmoscopy before and during a period of OPP decrease induced by blood draw to lower blood pressure or by manometric IOP elevation. Vessel diameter responses to the OPP decrease were compared between Cx43-downregulated and control-injected eyes. The extent of Cx43 downregulation was evaluated by Western blot and immunohistochemistry.ResultsIn control eyes, the OPP decrease induced dilatation of arterioles, but not venules. In Cx43-downregulated eyes, Cx43 expression in whole retina was decreased by approximately 40%. In these eyes, the resting diameter of the venules increased significantly, but there was no effect on arterioles. In Cx43-downregulated eyes, vasoreactivity evoked by blood pressure lowering was significantly compromised in both arterioles (P = 0.005) and venules (P = 0.001). Cx43 downregulation did not affect the arteriole responses to IOP elevation, whereas the responses of the venules showed a significantly greater decrease in diameter (P < 0.001).ConclusionsThe downregulation of retinal Cx43 in GFAP–expressing cells compromises vasoreactivity of both arterioles and venules in response to an OPP decrease achieved via blood pressure lowering or IOP elevation. The results also suggest that Cx43-mediated glial communication actively regulates resting venular diameter.

Evaluation for Dry Eye and Intra Ocular Pressure in Patients on Antihypertensive Medications

The study was conducted to evaluate and analyze the ocular side effects of antihypertensive drugs in the patients and to determine the effects of antihypertensive drugs in causing dry eye disease and intra ocular pressure changes. This was a case-control, noninterventional study of 140 patients (70 cases and 70 controls) conducted from June 2014 to May 2015 in Dr. Rajendra Prasad Government Medical College, Kangra at Tanda, Himachal Pradesh (India). Patients were subjected to detailed history and examination using standardized protocol and Performa. The prevalence of dry eye in this study was 44.3% in cases and 7.1% in controls, with p value of 0.0001 (<0.05), which is significant. Dry eye was present in all the patients on beta blockers and thiazide diuretics (alone or with combination). Dry eye disease was significantly associated with increasing age and longer duration of antihypertensive treatment. It was observed that average IOP was lower in patients on antihypertensive treatment as compared to normal subjects.

Effect of ophthalmic viscosurgical devices on post cataract intra ocular pressure changes and an assessment of their relative protective effect: a randomized controlled study

Background: Manual small incision cataract surgery (MSICS) has emerged as a popular technique in the ophthalmic practice. Ophthalmic viscosurgical devices (OVDs) are an integral part of the modern ophthalmic practice their role came to prominence with the success of extra capsular cataract extraction (ECCE) and the use of intra ocular lens implants (IOLs).There are few published data about the effect of various OVDs following manual small incision cataract surgery. Aims and objective: To determine post operative intra ocular pressure(IOP) changes after MSICS technique upon using OVDs; hydroxy propyl methyl cellulose (HPMC) and sodium hyaluronate (NAH) and also to assess the post operative protective effect of these two OVDs on cornea. Methodology: Sample of 60 senile cataract patients selected from the outpatient department of Ophthalmology and divided into 2 equal groups of 2%HPMC(Group A) and 1%NAH(Group B).MSICS technique was adopted for cataract surgery .Pre and postoperative IOP was assessed using Goldmann applanation tonometer and the cornea was examined under slit lamp Biomicroscope. Data was statistically analyzed using SPSS (statistical package of social sciences) version 16.01. A value of p

To compare Intra Ocular Pressure changes after isometric exercise of hand and leg muscles in young adults

Objective: To compare IOP changes after isometric exercise of hand and leg muscles Method: Healthy young male adults in the age group of 18-22 years were selected among MBBS students of JSS Medical college .Sample size was 40. Heart rate and IOP were recorded at rest and after isometric leg press test. Results: Right eye IOP has decreased significantly from resting 16.281.55 to 13.341.32 (p 0.001) immediately after handgrip exercise Right eye IOP has decreased significantly from resting 16.281.55 to 9.301.79( p 0.001)immediately after leg press exercise. Left eye IOP has decreased significantly from resting 16.151.69 to 13.041.19 (p 0.001) immediately after handgrip exercise Left eye IOP has decreased significantly from resting to 16.151.69 to 8.911.74 ( p 0.001)immediately after legpress exercise. Conclusion: Isometric leg press exercise lowers IOP which were significant. Reduction of IOP was more with leg press than Hand grip exercise.Hence may prove useful in normotensive glaucomatous patients.

Intraocular Pressure and Corneal Curvature Changes on Application of Limbal--Scleral Suction Fixation Ring in Rabbits

Suction rings are used to stabilize the globe during refractive surgery procedures. This study investigates the changes in ocular pressure and corneal curvature induced by a suction ring on rabbit corneas. A sharp rise in intraocular pressure, to as high as 80 mm Hg, followed by a time-dependent decline was found. The application of this ring also caused astigmatic changes in the cornea. Corneal thickening was also encountered. These findings have implications for possible artifactual changes during photorefractive keratoplasty and raise the possibility of intraocular pressure-induced damage in susceptible individuals.

Spontaneous trends in ocular pressure in untreated ocular hypertension.

Sixty ocular hypertensive patients receiving no treatment with ocular pressures of 21 mm Hg or more were followed up for a median time of 42 months for changes in ocular pressure. Three significant patterns were observed--stability, downward trend, or an upward trend. The majority of patients showed relatively stable pressures over the course of time. Cyclic swings of pressure over one- or two-year periods were also observed. A group of 43 normal patients with ocular pressures less than 21 mm Hg showed no trends of pressure with time except for three who had a small increase. For some patients, ocular hypertension appears to be a specific entity that represents either stable pressures with time or an episode of increased pressure that eventually decreases. In patients whose pressures continue to increase, ocular hypertension may become true glaucoma. Evaluation of the course of ocular hypertension in relation to diagnosis and treatment is important, especially in terms of the efficacy of treatment.