Marked Elevation Of Intraocular Pressure Research Articles

Primary Angle-Closure Disease Preferred Practice Pattern®

BackgroundPrimary angle closure disease (PACD) is classified into several groups. Primary angle closure suspect is defined as ≥ 180 degrees of iridotrabecular contact (ITC) without intraocular pressure (IOP) elevation, peripheral anterior synechiae (PAS), or optic nerve damage. An eye with ≥ 180 degrees of ITC and elevated IOP or PAS is categorized as primary angle closure, and the additional presence of glaucomatous optic neuropathy indicates primary angle closure glaucoma. Acute angle-closure crisis (AACC) represents a sudden, marked IOP elevation with complete ITC. Plateau iris configuration is defined as a narrow angle due to an anteriorly positioned ciliary body with a deep central anterior chamber, and plateau iris syndrome is persistent ITC after laser peripheral iridotomy (LPI). Although 90% of cases of AACC present unilaterally, PACD is generally bilateral. Risk factors for PACD include Asian descent, hyperopia, older age, female gender, short axial length, and thick and anteriorly positioned crystalline lens. Rationale for TreatmentPupillary block is involved in the pathogenesis of PACD in most cases, and is resolved with LPI. Patients experiencing AACC should receive medical treatment to lower the IOP, and LPI should subsequently be performed in both eyes. Lens extraction has also been shown to be an effective treatment in some patients with primary angle closure and primary angle closure glaucoma. Care ProcessThe goals of managing patients with PACD are to reverse or prevent angle closure and to control IOP to prevent glaucomatous optic nerve damage. Dark-room dynamic gonioscopy should be performed to diagnose PACD and verify improvement in angle configuration following treatment. Ultrasound biomicroscopy and anterior segment optical coherence tomography can also aid in the diagnosis of PACD.

Relationship between Elevated Intraocular Pressure and Divided Peripapillary Sector Retinal Nerve Fiber Layer Thickness in a Cynomolgus Monkey Laser-Induced Ocular Hypertension Model

Aims: We investigated the relationship between elevated intraocular pressure (IOP) and changes in global and peripapillary sector retinal nerve fiber layer (RNFL) thickness around the optic nerve head (ONH) in the laser-induced ocular hypertension monkey model. Methods: To induce high IOP, green laser photocoagulation burns were applied around the trabecular meshwork of 1 eye from each of 12 cynomolgus monkeys. The animals had been acclimated to IOP measurement under conscious conditions for more than 2 months, and IOP was chronologically measured. RNFL thickness was measured for 6 peripapillary sectors and global area using spectral-domain optical coherence tomography. Results: After model induction, marked IOP elevation and enlarged optic disk cupping were observed. Thinning of the RNFL associated with elevated IOP was observed around the ONH from 6 until 9 weeks after laser treatment, and the degree of reduction in RNFL thickness varied between the peripapillary sectors. Correlations between cumulative IOP elevation and RNFL thickness reduction were statistically significant for the temporal-superior (p = 0.024), nasal-inferior (p = 0.044), and temporal (p = 0.049) sectors, and global RNFL (p = 0.018). Conclusions: These results suggest that this model reflected the pathology of clinical glaucoma in terms of the specific pattern of RNFL thinning around the ONH.

Cesarean section and eye disorders

Recently, a growing tendency for cesarean birth has been noted both, in Poland and worldwide. Non-obstetric problems constitute a large part of indications for cesarean section. Many ophthalmologists and obstetricians still believe that high myopia, the presence of peripheral retinal degenerations, history of retinal detachment surgery, diabetic retinopathy, or glaucoma are indications for surgical termination of pregnancy. However, these recommendations are not evidence-based. The literature offers no proof that high myopia and previous retinal surgery increase the risk of retinal detachment during spontaneous vaginal delivery. There is only one indication for cesarean section in myopic patients, i.e. the presence of choroidal neovascularization, which can cause subretinal bleeding with acute visual loss. Prolonged and intensified Valsalva maneuver during labor in patients with an active proliferative diabetic retinopathy may be an indication for an elective cesarean section. Uterine contractions during the second stage of vaginal delivery lead to a marked elevation of intraocular pressure. Intraocular pressure fluctuations during the delivery may damage retinal ganglion cells, resulting in further progression of visual field. Thus, glaucoma associated with advanced visual field changes is the next ophthalmic indication for cesarean section. The report presents the current state of knowledge concerning the effect of pregnancy on pre-existing ocular disorders and the influence of physiological changes on the clinical course of these diseases during the stages of natural delivery. The authors discuss also the ophthalmic indications for cesarean section.

Intraocular pressure changes during hemodialysis.

The response of intraocular pressure (IOP) to hemodialysis procedure has been a subject of research throughout many decades. Several studies that evaluated the impact of hemodialysis (HD) on IOP have reported conflicting results and have drawn varied conclusions. Some studies have described an IOP elevation during HD, a finding they attributed to the osmotic disequilibrium between serum and aqueous humor induced by the HD procedure, especially when the facility of the outflow system is already compromised. On the other hand, several studies have reported a significant IOP decrease during HD. The majority of these studies supported the notion that the increase in plasma colloid pressure induced by fluid removal during the HD session is the underlying cause of decreased IOP. Finally, recent investigations did not establish a significant change in IOP measurements during HD. They have therefore suggested that improved dialysis techniques, such as high-flux HD, or hemofiltration and better urea control, maintain better osmolar balance and prevent a marked IOP elevation. Nevertheless, specific preventive measures are still necessary in HD patients with ocular pathologies (e.g., glaucoma) whose vision may be adversely influenced by significant IOP fluctuation.

Delayed intraocular pressure elevation after pupillary dilation in exfoliation syndrome

To determine the effect of pupillary dilation on intraocular pressure (IOP) in normotensive patients with exfoliation syndrome (XFS). Patients with XFS were enrolled in this prospective trial. All eyes were untreated, had no previous laser or operative surgery and were normotensive with full visual fields and open angles. IOP was measured before dilation and hourly for four consecutive hours after dilation with tropicamide 1% and phenylephrine 2.5% eyedrops. Twenty-five eyes of 19 White patients (nine male, 10 female) with XFS were enrolled. Twelve eyes (48%) had a rise in IOP of ≥ 4 mmHg above the pre-dilation baseline IOP and four (16%) had a rise of ≥ 9 mmHg (9-28 mmHg). Post-dilation gonioscopy confirmed the presence of an open anterior chamber angle in all eyes. The maximum IOP was reached 3 hr post-dilation in three eyes and after 2 hr in the remaining eyes. The four eyes with marked IOP rise exhibited an elevation of between 1 and 7 mmHg at 1 hr. Extensive pigment release was noticed in all eyes that had a rise in IOP. Patients with XFS are at risk of developing delayed post-dilation IOP rises. Awareness of this phenomenon is particularly important in patients with advanced cupping and/or severe visual field loss who may not be able to tolerate a marked elevation of IOP. An early, mild rise in IOP at 1 hr may serve as a warning sign for a more severe, delayed response. Eyes with XFS should be monitored carefully after dilation, especially those with marked pigment release.

Evaluation of Aqueous Outflow Facility in Patients With High Intraocular Pressure After Cataract Surgery

To study whether patients with a marked elevation of intraocular pressure (IOP) the day after cataract surgery may have a chronically impaired aqueous outflow. In 128 consecutive patients, IOP was measured both preoperatively and the day after phacoemulsification and intraocular lens implantation. In the late postoperative period, aqueous outflow facility (C-value) was measured with pneumatonography in patients (n = 7) who experienced a postoperative IOP increase of at least 20 mm Hg and in patients (n = 11) with a difference between preoperative and postoperative IOP of not more than 2 mm Hg. Aqueous outflow facility was normal in both groups. Mean C-value was 0.32 +/- 0.18 microL/min/ mm Hg in the hypertensive group and 0.23 +/- 0.10 microL/ min/mm Hg in the normotensive group. The difference was not statistically significant (P = .20). Patients with marked IOP elevation the day after cataract surgery do not seem to have a chronically impaired aqueous outflow facility compared with normotensive patients.

Intraocular pressure lowering effect of dosed laser coagulation of the corneoscleral trabeculum. I. Tonographic analysis of the early postoperative phase

In 10 eyes suffering from glaucoma simplex, trabeculoplasty (TBP) was performed in the lower half of the corneoscleral trabeculum. Using an applanation tonometer, the diurnal pressure was recorded for 8 days and tonography performed daily at 10 a.m. TBP was performed at 9:30 a.m. on the second day. The results of this study revealed a marked elevation of intraocular pressure immediately after the TBP, accompanied by a highly significant increase in the resistance to aqueous outflow (R) and an equally highly significant fall in the minute volume of aqueous flow (F). During the following 6 days the intraocular pressure remained lower, the drop in R was significant for two days but not at the end, and the fluctuations of F were negligible throughout.

Sickle Cell Hyphema With Secondary Glaucoma in a Non-Black Patient

A 5-year-old Mexican-American boy developed marked elevation of intraocular pressure in association with a small traumatic hyphema. Laboratory studies prompted by this clinical presentation revealed that the child had sickle trait. Pressure returned to normal after surgical evacuation of blood from the anterior chamber. Sickle cell hemoglobinopathy should be considered in the differential diagnosis of secondary glaucoma following blunt ocular trauma even in non-black patients.