Acute Intraocular Pressure Rise Research Articles

Canaloplasty in Pseudoexfoliation Glaucoma. Can It Still Be Considered a Good Choice?

Purpose: The aim of this study was to assess the long-term outcomes of canaloplasty surgery in pseudoexfoliation glaucoma (PEXG) patients. Material and Methods: A total of 116 PEXG patients with an intraocular pressure (IOP) > 21 mm/Hg and maximum tolerated local medical therapy who underwent canaloplasty from February 2008 to January 2022 were considered. Every six months, all subjects underwent a complete ophthalmic examination. The period of follow-up ranged from 2 to 167 months. Inclusion criteria included only patients for whom the entire procedure could be completed with a follow-up of at least 2 years. Results: Amongst the 116 PEXG patients, the entire procedure could not be performed in 10 eyes (8.6%), and thus they were not considered in the analysis. Twenty-three patients did not reach the two-year follow-up and another 16 patients during this time period were lost. A total of 67 patients with a mean follow-up of 49 ± 32.3 months were considered in the analysis. The pre-operative mean IOP was 31.2 ± 8.7 mm/Hg (range 20–60). The mean IOP at the two-year follow-up was 17.2 ± 6.7 mmHg, with a mean reduction from baseline of 44.9%. After two years, the qualified success rates according to three different criteria (IOP ≤ 21, ≤18 and ≤16 mmHg) were 80.6%, 73.1% and 61.0%, respectively. The total number of medications used pre- and at the follow-up at 2 years was 3.5 ± 0.8 and 1.2 ± 1.4, respectively. Early complications included: hyphema, in about 30% of cases; Descemet membrane detachment (4.9%); and IOP spikes > 10 mmHg (9.7%). A late failure with an acute IOP rise of up to 50 mmHg was observed in 41 cases (61.2%) after 3 to 72 months. Conclusions: Long-term post-operative outcomes of canaloplasty in PEXG patients appear to be quite good on average; however, an acute rise in IOP can be observed in more than 60% of the cases after a long period of satisfactory IOP control. For this reason, canaloplasty may not be suitable in eyes with PEXG, especially in patients with severe functional damage.

Efficacy of Timolol Maleate (0.5%) in Preventing Rise of Intraocular Pressure (IOP) Post Neodymium: Yttrium Aluminum Garnet (Nd: YAG) Capsulotomy

Objective: To determine the efficacy of 0.5% Timolol eye drops in preventing rise of intraocular pressure following Neodymium: Yttrium-Aluminum-Garnet laser posterior capsulotomy.
 Study Design: Quasi-experimental study.
 Place and Duration of Study: Outpatient Department of Ophthalmology, Combined Military Hospital Multan Pakistan, from May to Nov 2019.
 Methodology: Patients presenting with posterior capsule opacification, undergoing elective Neodymium: Yttrium Aluminum Garnet (Nd: Yag) Capsulotomy were enrolled in the study. Patients were alternatively assigned to two groups; group-1 was administered 0.5% Timolol Maleate eye drops, while group-2 was administered placebo natural team eye drops. Intraocular pressure for all the patients was measured at three-time points a). First measurement was baseline intraocular pressure at presentation/before the treatment. Second measurement was 1-hour post laser capsulotomy and third measurement was 3 hours post laser capsulotomy.
 Results: At 1-hour follow up, the mean intraocular pressure was significantly raised in the patients belonging to control group as compared to treatment group (21.45 ± 8.33 mm Hg vs 15.33 ± 3.37 mm Hg, p<0.001). At 3-hours follow-up the mean intraocular pressure decreased a bit for control group but still was significantly higher than the treatment group (17.40 ± 3.00 mm Hg vs 15.60 ± 2.30 mm Hg, p<0.001).
 Conclusion: Prophylactic use of Timolol successfully reduces the post-procedural acute rise in intraocular pressure due to Neodymium: Yttrium Aluminum Garnet laser posterior capsulotomy.

The Effect of Acute Rises in Intraocular Pressure after Intravitreal Bevacizumab Injection on the Peripapillary Retinal Nerve Fiber Layer Thickness and the Role of Anterior Chamber Paracentesis.

Purpose:To evaluate acute changes in intraocular pressure (IOP) and their short-term effects on the peripapillary retinal nerve fiber layer (RNFL) thickness after intravitreal bevacizumab (IVB) injection.Methods:Fifty-eight eyes of 37 patients with treatment-naïve diabetic macular edema or exudative age-related macular degeneration were included in the study. Patients were divided into two groups, and the participants of each group received 3 monthly injections of IVB. IOP was measured right before the injection, immediately after the injection, and 5 min and 20 min after each injection. Peripapillary, RNFL thickness was measured before the injection and 1 month after the third injection. In the second group, anterior chamber (AC) paracentesis was performed before IVB injection.Results:IOP values after injection in all sessions were significantly higher in the first group (P < 0.001). The peripapillary RNFL thickness changes 1 month after the third injection was not statistically significantly different in each group (P = 0.816 and 0.773 for the first and second groups, respectively).Conclusion:AC paracentesis is an effective modality to reduce the acute rise in IOP. The effect of acute IOP elevation on the peripapillary RNFL thickness was not statistically significant.

Changes of retinal and choroidal capillary blood flow in macula after an acute intraocular pressure elevation.

The aim of this study was to investigate the changes of retinal vessel density (VD) and choriocapillary blood flow area (CBFA) in macula after an acute intraocular pressure (IOP) elevation observed using optical coherence tomography angiography.This was a prospective comparative study of subjects with narrow anterior chamber angles who underwent laser peripheral iridotomies (LPIs). The IOP was measured before and 1 hour after the LPI. The retinal VDs and CBFAs of the macula were measured using optical coherence tomography angiography at the baseline and 1 hour after the LPI.A total of 88 eyes of 88 individuals were enrolled in our study, and 70 eyes of 70 individuals finally completed the study with a mean IOP rise of 10.2 ± 7.5 mm Hg after the LPI. The VDs and areas of foveal avascular zone of all of the subjects did not differ significantly between the measurements obtained at the baseline and 1 hour after the LPI (P > .05). However, there were statistically significant differences in the CBFAs at the baseline and 1 hour after the LPI (P < .05). Based on the magnitude of the rise in the IOP, we divided the subjects into three groups: group A = IOP rise ≤ 10 mm Hg, group B = 10 mm Hg < IOP rise ≤20 mm Hg, and group C = IOP rise > 20 mmHg. The VDs of the macula measured at the baseline were significantly different from the measurements obtained 1 hour after the LPI in group C in either the superficial retinal layer or deep retinal layer (P < .05). Compared with baseline, the CBFAs measured at 1 hour after the LPI were decreased in group B and group C (P < .05).In these subjects with narrow antenior chamber, the blood flow in macula began to be affected with the acute IOP rise greater than 10 mm Hg. It was confirmed that the retina and choroid showed some different ability to regulate its blood flow in response to changes in IOP.

Determinant Factors of Intraocular Pressure Responses to a Maximal Isometric Handgrip Test: Hand Dominance, Handgrip Strength and Sex

ABSTRACT Purpose To assess the mediating role of strength levels, hand dominance and participants´ sex on the intraocular pressure (IOP) behaviour during the execution of a maximal isometric handgrip test. Methods One hundred and seventy-six sport science students (102 men and 74 women) performed a maximal isometric handgrip test with the dominant and non-dominant hands. A rebound tonometer was used to measure IOP before effort, during effort, and immediately after performing the handgrip test. Men and women were divided based on their handgrip strength in low- and high-strength groups using a median split analysis. Results There was an acute IOP rise during effort, returning to baseline levels immediately after exercise cessation (P < .001, ηp 2 = 0.79). A greater increase in IOP during the execution of the handgrip test was observed for the dominant-hand compared to the non-dominant hand (P = .004, d = 0.30) and for men compared to women (P = .001, d = 0.90). The main effect of strength level did not reach statistical significance (P = .266). Conclusions The IOP rise associated with a maximal isometric handgrip effort is affected by the participants´ sex (men > women) and hand dominance (dominant hand > non-dominant hand), but not on strength levels. These findings need to be corroborated in glaucoma patients.

Impact of resistance training sets performed until muscular failure with different loads on intraocular pressure and ocular perfusion pressure.

The aim of this article is to investigate the acute effects of bench press sets leading to muscular failure with different loads on intraocular pressure and ocular perfusion pressure. A randomized experimental study. Seventeen physically active young men performed four resistance training sets of bench press to muscular failure against different relative loads (65% one-repetition maximum vs 75% one-repetition maximum vs 85% one-repetition maximum vs 95% one-repetition maximum). Intraocular pressure was measured before and immediately after the execution of each of the four sets, and ocular perfusion pressure was also assessed before and after physical effort. We found that intraocular pressure increased after reaching muscular failure (p < 0.001, ƞ²= 0.52), being also dependent on the interaction load × point of measure (p < 0.001, ƞ²= 0.33). Our data demonstrated that higher intraocular pressure increases were found when participants performed the bench press exercise against heavier loads, showing statistical significance for the 75% one-repetition maximum (p = 0.020, d = -0.63, mean change = 0.9 mmHg), 85% one-repetition maximum (p = 0.035, d = -0.56, mean change = 1.4 mmHg), and 95% one-repetition maximum (p < 0.001, d = -1.36, mean change = 2.9 mmHg) relative loads. For its part, ocular perfusion pressure showed a reduction after exercise (p = 0.009, ƞ²= 0.35), being these changes independent on the load used. Bench press exercise leading to muscular failure provokes an acute intraocular pressure rise, with greater changes when heavier loads are used. Ocular perfusion pressure exhibited an acute reduction after exercise; however, its clinical relevance seems to be insignificant (lower to 4%). We argue that the use of heavy loads, when training to muscular failure, should be discouraged in order to avoid acute intraocular pressure fluctuations. Future studies should corroborate the generalizability of these findings in glaucoma patients.

Lamina cribrosa pore movement during acute intraocular pressure rise

PurposeTo assess changes in the position of lamina cribrosa pores (LCPs) induced by acute intraocular pressure (IOP) elevation.MethodsA prospective observational study. Acute angle-closure suspects who underwent the 2-hour dark room...

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

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. 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. 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). 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). 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.

FREQUENCY OF ACUTE RISE OF INTRAOCULAR PRESSURE FOLLOWING YAG LASER POSTERIOR CAPSULOTOMY

Background: Posterior capsular opacification (PCO) is the most frequent complication of cataract surgery. The objective of this study was to determine the frequency of acute rise of intraocular pressure (IOP) following Neodymium-Yttrium Aluminum Garnet (Nd:Yag) laser posterior capsulotomy. Materials &amp; Methods: This cross-sectional study was conducted in the Department of Ophthalmology, HMC, Peshawar, Pakistan, from July-December 2016. Sample size was 325 selected by consecutive sampling technique. Inclusion criteria were all patients having significant PCO after uneventful cataract surgery with intra ocular lens implant. Demographic variables were sex, age groups and age in years. Research variable was presence of acute rise of IOP following Yag laser capsulotomy. Pre-laser assessment included slit lamp examination and recording of IOP with Goldmann applanation tonometer by a single ophthalmologist. IOP was measured 3 hours after Nd: Yag laser capsulotomy. Rise in IOP was labeled when IOP was ≥5 mmhg from baseline. Mean ±SD was used to express quantitative variables like age. Categorical variables were analyzed as frequency and percentage. Goodness-of-fit was applied to compare the frequency of acute rise in IOP between sample and population. SPSS-20 was used for data entry and its analysis. Results: Out of 325 patients, 170(52.3%) were men and 155(47.7%) were women. The mean age of the sample was 44.92 ±23.843 years. A total of 107(32.9%) patients were 20-39 years old whereas 218(67.1%) were 40-70 years. IOP was raised in 61 (18.8%) patients while in 264(81.2%) patients it was not raised. The frequency of acute rise in IOP after Yag laser capsulotomy was significantly different in sample compared to population. Conclusion: Men were more than women, especially of old age. The frequency of acute rise in IOP after Yag laser capsulotomy was significantly different in sample compared to population.

Effects of intravitreal injection of bevacizumab with or without anterior chamber paracentesis on intraocular pressure and peripapillary retinal nerve fiber layer thickness: a prospective study.

To investigate the effects of intravitreal injection of bevacizumab (IVB) with or without anterior chamber paracentesis on intraocular pressure (IOP) and peripapillary retinal nerve fiber layer (PRNFL) thickness. In this prospective randomized clinical trial, 90 eyes with center involving diabetic macular edema or wet type age-related macular degeneration (AMD) were randomly assigned to receive IVB either without (group A) or with (group B) anterior chamber paracentesis. IOP was measured before and within 2 min, 30 min, 24 hours and 3 months after injections. Peripapillary spectral-domain optical coherence tomography (SD-OCT) was performed before and 3months after injections. Mean IOP changes 2 minutes, 30 minutes, 24 hours, and 3 months after injections were 26.4 ± 5.7 mmHg (P <0.001), 6.5 ± 6.3 mmHg (P <0.001), 0.2 ± 2.9 mmHg (P >0.99) and 0.5 ± 2.4 mmHg (P >0.99) in group A and -1.3 ± 2.4 mmHg (P <0.001), -3.2 ± 1.8 mmHg (P <0.001), -3.1 ± 1.8 mmHg (P <0.001) and -1.8 ± 2.2 mmHg (P <0.001) in group B, respectively Mean baseline average PRNFL thickness was 85.3±5.6 μm and 85.6 ± 5 μm in groups A and B respectively. Mean PRNFL thickness changes after 3 month was -2 ± 2 μm (P <0.001) in group A and 0 ± 2 μm (P =0.101) in group B. Mean PRNFL thickness in group A decreased more than group B (P <0.001). Conventional method of IVB injection was associated with acute IOP rise and significant PRNFL loss 3 months after injection. Anterior chamber paracentesis prevents acute IOP rise and PRNFL loss.

Real-time measurement of needle forces and acute pressure changes during intravitreal injections.

The purpose of this study was to use a physiological pressure transducer to measure real-time, continuous pressure changes in an ex vivo study model of porcine eyes to record the amount of force needed for scleral penetration and to measure acute intraocular pressure rise during intravitreal injections. A pressure transducer was inserted into the anterior chamber of 30 fresh porcine eyes, and intraocular pressure was measured 2s prior to intravitreal injection until 2s after. A force transducer plate was used to insert various gauge needles into the vitreous cavity and the amount of force in Newtons (N) required for scleral penetration was recorded. For scleral perforation, 32- and 30-gauge needles required 0.44N and 0.45N, significantly less than larger gauge needles (P<0.05). Similarly, 27- and 25-gauge needles required more force than smaller gauge needles but less than 19 gauge (P<0.05). Intraocular pressure increased an average of 64.5mmHg during intravitreal injection. Two seconds postinjection intraocular pressure readings showed a residual intraocular pressure increase of 11.1mmHg from pre-injection baseline. Real-time continuous recordings of pressure reveal that an instantaneous intraocular pressure spike occurs during intravitreal injection and appears to be separate from the intraocular pressure spike that occurs during needle insertion. This pressure spike is transient and has not been captured by previous methods of intraocular pressure measurement, which rely on single time point measurements. The clinical significance of this brief intraocular pressure spike is unclear and warrants further investigation.

Angle Closure and the Acute Rise of Intraocular Pressure after Administration of Methazolamide

Angle Closure and the Acute Rise of Intraocular Pressure after Administration of Methazolamide

An Experimental Study to Evaluate the Effects of Adenosine on Intraocular Pressure in Conscious Albino Rabbits

Introduction: Glaucoma is a common problem globally which can lead to irreversible blindness. It is characterized by progressive optic nerve damage. Though its definition doesn’t include elevated intraocular pressure but it is known that elevated intraocular pressure is the main culprit behind development of glaucoma. There are various medical and surgical treatment for glaucoma but none are without risk. None of the existing modalities leads to desired control of intraocular pressure and combined approach is needed for the treatment. The study is aimed to evaluate the activity of adenosine, a vasoactive agent, on intraocular pressure in rabbits as the search of newer agents for treatment and prevention of glaucoma.Methods: The study was carried out in albino rabbits using two experimental models viz. water loading model (acute) and steroid induced model (chronic) to induce glaucoma. Intraocular pressure lowering effects of adenosine was studied in both models. IOP was measured with Schiotz tonometer. The intraocular pressure measurement was converted in to mm of Hg by using a IOP conversion chart.Results: Adenosine significantly prevented the acute rise in intraocular pressure in water loading acute model of glaucoma and significantly reduced intraocular pressure in chronic dexamethasone induced glaucoma model. The maximum mean difference in IOP between control and adenosine treated eyes were 15.29% in intragastric tap water loading model. The maximum IOP reduction was 33.52% in chronic model induced by dexamethasone (0.1%).Conclusion: Adenosine reduces the intraocular pressure in rabbits with experimentally induced glaucoma. This activity of adenosine needs to be confirmed and validated through further experimental and clinical studies.

Reversibility of Retinal Pigment Epithelium Detachment Parallel to Acute Intraocular Pressure Rise

Reversibility of Retinal Pigment Epithelium Detachment Parallel to Acute Intraocular Pressure Rise

Acute Peripapillary Retinal Pigment Epithelium Changes Associated with Acute Intraocular Pressure Elevation

To assess changes in the peripapillary retinal pigment epithelium (RPE) in association with an acute intraocular pressure (IOP) elevation provoked by a dark room prone provocative test (DRPPT). Prospective, comparative clinical observational study. Nineteen study group eyes (14 individuals) and 26 control eyes (21 patients). Individuals with normal optic nerve heads (ONHs) underwent a DRPPT in a standardized manner. They were stratified into a study group with an IOP rise of more than 15 mmHg at the end of the DRPPT and a control group with an IOP rise between 2 and 4 mmHg. Before and at the end of the test, the ONH was imaged by spectral-domain optical coherence tomography (OCT). Morphologic features of the RPE at the peripapillary end of Bruch's membrane. After a mean IOP rise by 32.1±9.5 mmHg (range, 17-47 mmHg), 18 (95%) eyes in the study group showed a folding or a centrifugal sliding, or both, of the end of the RPE layer on the peripapillary Bruch's membrane. The RPE changes were located most often at the temporal pole of the ONH (16 eyes [89%]), followed by the nasal pole (2 eyes [11%]). The RPE changes were not detected at the inferior or superior disc poles. Some eyes with marked RPE changes showed corresponding changes in peripapillary β zone on infrared ONH photographs. In 7 eyes of 7 participants with OCT images obtained on the day after the PRPPT, the RPE end moved back to the end of peripapillary Bruch's membrane. The single eye of the study group without exhibiting IOP rise-associated RPE changes showed an interdigitation zone line indistinguishable from Bruch's membrane line on OCT images. None of the control eyes showed RPE changes. The difference in frequency of RPE changes between study and control groups was significant (P < 0.001). Eyes with an acute rise in IOP (>15 mmHg) showed a folding and centrifugal sliding of the peripapillary RPE and, after IOP reduction, centripetal RPE movement. These observations may be of interest to elucidate the pathogenesis of peripapillary atrophy in glaucoma.

Dynein, kinesin and morphological changes in optic nerve axons in a rat model with cerebrospinal fluid pressure reduction: the Beijing Intracranial and Intraocular Pressure (iCOP) study.

To examine the influence of experimentally reduced cerebrospinal fluid pressure (CSFP) as compared to elevated intraocular pressure (IOP) on axonal morphology and axonal motor proteins in retinal ganglion cells (RGCs). The experimental study included 39 rats which underwent cerebrospinal fluid drainage for 6 hr, 30 rats which unilaterally underwent IOP elevation for 6 hr and 30 rats in a control group. Six hours after baseline, the animals were killed and the eyes were histologically and immunohistochemically examined. In experimental models in the high-IOP group and the low-CSFP group as compared to the control group, RGC axons became abnormally dilated and accumulated vesicles. Both groups as compared to the control group showed an accumulation of dynein IC (intermediate chain) at the optic nerve head and retina and a reduction in kinesin HC (heavy chain) immunoreactivity in the optic nerve fibre axons. As a corollary, Western blot analysis revealed an elevation of dynein IC protein levels in the optic nerve head and retina and a decrease in kinesin HC protein levels in the optic nerve. Experimental models with an acute IOP rise or with an acute CSFP reduction showed similar morphologic changes in the retinal ganglion cell axons and similar immunohistochemical changes in the axonal motor proteins kinesin HC and dynein IC. It supports the hypothesis that an experimental model with an acute reduction in CSFP as well as an experimental model with an acute rise in IOP may share similarities in the process of optic nerve damage.

Neuroprotective effects of topical CB1 agonist WIN 55212-2 on retinal ganglion cells after acute rise in intraocular pressure induced ischemia in rat

Neuroprotection in retinal experimental work consists primarily of preventing retinal ganglion cell (RGC) loss after exposure to a hostile event. We have studied the neuroprotective effect on RGCs in an ischemia-reperfusion model by activation of the cannabinoid receptor CB1 using topical application of WIN 55212-2. Intraocular pressure (IOP) was increased by continuous infusion of phosphate buffer saline (PBS) into the anterior chamber of the eye. Mean intraocular pressure was increased up to 88.5 ± 0.29 mm Hg (control normal IOP 15.1 ± 0.25 mm Hg), for 35 min. Animals were distributed in 3 groups. Left eyes underwent acute rise in intraocular pressure. First group was treated with topical Tocrisolve™ 100 in both eyes. Second group was treated with 1% solution of CB1 agonist WIN 55212-2 in both eyes. Third group was treated with WIN 55212-2 1% and CB1 antagonist AM 251 1% solutions in both eyes. Subsequently, RGCs were immunolabeled with Brn3a and automated quantification of retinal mosaics of RGCs were performed. The ischemic damage led to a mean loss in RGC density of 12.33%. After topic administration of WIN 55212-2, mean loss of RGCs was of 2.45%. Co-treatment with CB1 antagonist AM 251 abolished almost completely the neuroprotective effect of WIN 55212-2. Topic 1% WIN 55212-2 showed a neuroprotective effect on RGC degeneration after ischemia-reperfusion without pre-activation of CB1 receptors.

A Prospective Study to Analyse the efficacy of Apraclonidine in Preventing Intraocular Pressure Rise After Neodymium: YAG (Nd-YAG) Laser Posterior Capsulotomy

Objective: To analyse the efficacy of (0.5%) apraclonidine in preventing the acute rise of intraocular pressure following Nd-YAG Laser posterior capsulotomy. Material and method: A prospective case controlled randomised study was performed in the department of ophthalmology of SIMS in collaboration of department of pharmacology. Result: A total 52 patients were divided in two groups. Half of the patients were given 0.5% topical apraclonidine 15 minutes before the procedure and immediately after the procedure and after 1 hr, 2hr, and 4hrs respectively. The other half were not given any IOP lowering drug.IOP was measured by tonometry. There was significant fall in IOP in test group patients. IOP in two groups 1hr after procedure was 13.08% rise in control and 6.40% fall in test group. Conclusion: Apraclonidine, a highly selective alpha2 adrenoceptor agonist effectively and safely lowers IOP spikes after laser treatment without causing significant side effects like bradycardia or hypotension.

Intraocular pressure elevation during early postoperative period after secondary intraocular lens implantation in children and adolescents

To look at the intraocular pressure (IOP) spike in the early postoperative period after secondary intraocular lens (IOL) implantation in children. Miles Center for Pediatric Ophthalmology, Medical University of South Carolina, South Carolina, USA. Retrospective chart review. The postoperative day-1 examination of patients having secondary IOL implantation by the same surgeon was reviewed for an IOP greater than 26 mm Hg. In patients with an IOP spike, the medical history and examination findings that might be associated with the rise were evaluated. Review of 85 patient charts (133 eyes) identified 9 eyes that developed an IOP spike during the early postoperative period. Six eyes were symptomatic, with symptoms including pain, ocular discomfort, nausea, and emesis, and 6 eyes had preoperative aphakic glaucoma, which was controlled with medication. Six of 22 eyes (27%) with preoperative aphakic glaucoma and 3 of 111 eyes (3%) without glaucoma (P<.001) developed an acute IOP rise (relative risk, 10.1). The high incidence of a symptomatic early IOP spike in patients with aphakic glaucoma warrants meticulous ophthalmic viscosurgical device removal at the end of surgery, consideration of the routine use of prophylactic topical and/or systemic glaucoma medication, and monitoring during the early postoperative period.

The effect of topical administration of sildenafil in acute ocular hypertension model in rabbits.

Background: Nitric oxide ( NO) is a physiological mediator of many processes in the eye including regulation of aqueous humor dynamics. Compounds acting via NO dependent mechanisms may enhance aqueous humor outflow and reduce intraocular pressure (IOP) .Objective: Sildenafil a cGMP specific phosphodiesterase 5inhibitor that potentiates NO production and increases cyclic GMP is tested in this study for its effects on intraocular pressure in an acute ocular hypertension model in rabbits.Materials and methods: Newzealand albino rabbits of either sex weighing 2–2.5 Kg , were used in this study. Sildenafil was prepared in a vehicle of phosphate buffer and diluted to the required strength of 0.5%. Intraocular pressure (IOP ) was measured after 45 seconds of one drop of proparacaine topical anesthesia by using schiotz indentation tonometer. Basal IOP was obtained for both eyes using 12 rabbits .One drop of sildenafil (0.5%) was then topically instilled in the left eye while the right eye received the vehicle and served as a control. After 30 minutes of drug and vehicle administration the IOP was measured in both eyes and acute ocular hypertension was induced by the administration of 15ml/kg 5% glucose. The IOP was then recorded every 15 min for 180 minutes.Results: Topical 0.5% sildenafil administration had no effect on the basal IOP levels. However sildenafil significantly (p &lt; 0.05) attenuated the acute rise in IOP induced by 5% glucose infusion. The IOP levels returned to their basal values in shorter time with sildenafil compared to the controlConclusion: Topical sildenafil pretreatment reduces IOP in acutely induced intraocular hypertension.