الفهرس 
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Abstract
PEX syndrome is a severe chronic secondary open-angle glaucoma and cataract that often occurs as a result of aging and a disturbance of the extracellular matrix. Up to 30 percent of the over-60 population might be affected by PEX on a global scale. A number eye factors, including the loss of pigment from the pupillary ruff and iris sphincter area and the formation of gray- white extracellular fibrillary material on anterior segment components, contribute to the progression of glaucoma.
There was a significant positive correlation between IOP and anterior chamber angle pigmentation in the PEX.
Progressive buildup of EXM in the iris stroma causes iris stiffness, hence iris alterations are commonly seen early in the course of PEX. Atrophy of the pupillary edge and the smooth iris dilator muscle, degeneration of the iris muscle cells, and increased iris stiffness are all symptoms of PEX that impede pupil dilation and reduce the iris’s responsiveness to mydriatics.
The most plausible explanation is that the development of PEX fibers triggers atrophy alterations in the radial and sphincter muscles of the iris. Subclinical posterior synechiae formation and intrastromal iris bleeding are two further potential causes of poor mydriasis in patients undergoing PEX.
Ophthalmologists often prescribe mydriatic drops for their patients, although these pharmaceutical agents have been shown to significantly increase IOP in certain individuals, including those with PEX.
Pupil dilatation causes a widespread release of pigment into the anterior chamber and, in eyes with PEX, an increase in IOP Because of the dilating pupil, this pigment is released from the iris pigment epithelium in the sphincter area [3] And during mydriasis, the aqueous humor drainage is obstructed by EXMs and pigment grains released by the iris pigment epithelium.
In patients with PEX, it is crucial to evaluate the anterior region, including CCT, ACD, PD, and ACA width. In these individuals, indirect indications of endothelial function may be found in assessments of corneal volume and corneal thickness. IOP evaluation in glaucoma patients now also relies heavily on corneal thickness measurement.
Scheimpflug imaging evaluates anterior segment characteristics such as ACD, ACA, CCT, CV at 3.0, 5.0, and 7.0 mm, and pupil size.[5] Scheimpflug imaging is a quick and painless noninvasive user-independent approach with excellent patient comfort. It is a fast, painless, and non-invasive way for assessing many different aspects of the anterior segment.
The study participants divided into 2 groups: group 1;pseudoexfoliative group and group 2 Control group
After slit lamp bio microscopy examination Full ophthalmological examination including
1.IOP using GAT.
2.Gonioscopy grading using Goldmann 3 mirrors.
3.Scheimpflug imaging using pentacam parameter
The above mentioned examinations will be done to each group after applying pharmacological mydriatics in 3 separate visits, with an interval between visits1week.
First visit: Examination before and after 2 hour of phenylephrine 2%. Second visit: examination before and after 2 hour of tropicamide 1% . Third visit: examination before and after 2hour of cyclopentolate HCL 1%.
Scheimpflug imaging, Goldmann applanation, and gonioscopy all showed similar pre-dilation anterior segment characteristics in both the PEX and control groups, whereas the CCT was considerably higher in the control group (525.1 ± 33.6 um vs.
499.24 ± 43.23 um, p= 0.049). This agrees with an older work by Bartholomew et al., where they also showed no change in ACD between 34 eyes of patients with PEX and 334 normal controls when using a Goldmann pachymeter. Moreno- Montaés et al. did another prospective analysis in 263 eyes (152 individuals) with PEX. When comparing ACD and ACA to healthy controls, no significant changes were seen. The same was true in a clinical trial conducted by Doganay et al., which compared 53 patients with PEX to 80 healthy eyes and found no statistically significant differences in ACD, ACV, ACA, CCT, PD, and central 3, 5, 7 mm corneal volume. Patient with PEX glaucoma, who were not included in our investigation, were shown to have a significantly different ACD compared to healthy controls. In our research, we found that both PEX patients and controls saw a statistically significant increase in PD after taking any of the three eye drops. When comparing post-dilation measurements between PEX patients and controls, further statistical analysis revealed a statistically significant difference only in the cyclopentolate group (4.5 ± 1 mm versus 5.2 ± 1 mm, p=0.031, respectively); when comparing post-dilation readings within PEX patients, we discovered a significantly highest reading in the phenylephrine group (P=0.017).
It is not well known why eyes with PEX and PXG have poor mydriasis. Possible causes include adhesions between the iris epithelium and the anterior lens capsule, hard iris stroma, or degenerative change of the iris dilator. In addition, we found that following pupillary dilatation, IOP increased in both PEX patients and controls, relative to pre-dilation readings. Patients with risk factors for angle-closure glaucoma, such as a narrow angle, may experience an acute attack of the disease after receiving pharmacologic pupillary dilation. This occurs when the iris is left in a position where its pupillary edge is not fully apposed to the anterior lens border, which can result in pupillary block and ultimately angle closure.
Patients with PEX are thought to mostly have open-angle type increased IOP due to blockage of the angle by the EXM. A number of causes, such as zonular weakness leading to anterior displacement of the lens-iris diaphragm, posterior synechiae, iris stiffness leading to relative pupillary block, and lens thickness, may all contribute to the development of angle closure. The posterior iris pigment epithelium rubbing against the deposits on the lens capsule is assumed to be the mechanism through which PEX causes pigment release in the eye. The relaxation of the ciliary muscle also contributes to IOP by reducing trabecular outflow.