الفهرس 
Anterior chamber angleOnly 14 pages are availabe for public view
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Abstract
Glaucoma is a major public health problem emerging as the second most common cause of blindness in the world and the major cause of irreversible blindness worldwide. As a result of its higher visual morbidity, the 5.3 million people who will be blinded by ACG is nearly equal to the number who will be blinded by open-angle glaucoma (OAG), despite the latter disease being three times more prevalent. Laser iridotomy has become the procedure of choice for relief of, or prophylaxis against pupillary block, having largely replaced surgical iridectomy. Ultrasound biomicroscopy (UBM) is a high resolution ultrasound technique which provides real-time cross-sectional images in a very cost-effective manner, even in the presence of optically opaque intervening media. UBM technology uses ultrasound frequencies in the35- 100 MHz range, which allows noninvasive in vivo imaging of structural details of the anterior ocular segment as well as quantitative measurements of the anterior segment in a semiautomated way. This prospective study included 30 eyes of 16 patients attended outpatient clinic of Ophthalmology Hospital, Tanta University during the period of the study. The study included patients presented with primary angle closure suspect (PACS), primary angle closure (PAC) and primary angle closure glaucoma (PACG). All patients underwent full clinical examination including: anterior segment examination, gonioscopy, IOP measurement and fundus examination for assessment of optic disk. Ultrasound bio microscopic examination was performed before and 6 weeks after LPI by the same ophthalmologist using Vu Max sonomed model. Quantitative evaluation of the angle has been done using several parameters; the position of the scleral spur (SS) used as reference point for most of these parameters because this is the only land mark clearly identified at region of the angle. Laser peripheral iridotomy (LPI) was performed using an Nd: YAG (neodymium-yttrium-aluminum-garnet) laser set at 2-6 mj. Statistical analysis has shown marked widening of trabecular iris angle (TIA), increase of angle opening distance (AOD), decrease of iris convexity (ID) and flattening of iris, increase of iris lens contact distance and decrease of iris lens angle in all patients of primary angle closure suspect and primary angle closure even in patients with primary angle closure glaucoma but without synechiae. On the other hand we didn’t find any significant changes after laser peripheral iridotomy by ultra sound bio microscopy in the parameters of trabecular ciliary process distance, iris ciliary process distance, iris thickness, ciliary body thickness, lens thickness and central anterior chamber depth. We found that there is underestimation of prevalence of angle closure disease in our country due to lack of gonioscopic assessment and lack of national survey for prevalence of glaucoma generally and angle closure glaucoma specially. We found that ultrasound bio microscopy is a very helpful tool in diagnosis of the disease and differentiating its sub types according to configuration of iris and its insertion on the ciliary body. Also ultra sound bio microscopy can help in detection of lens swelling and size and its thickness in relation to total axial length of the patient which helps us in taking proper surgical decision. We found good correlation between ultra sound bio microscopy and gonioscopy in detection of angle widening after laser peripheral iridotomy. More ever ultra sound bio microscopy was superior on gonioscopy in detection of angle widening in specific degrees not only in grades which can give an idea about long term out comes of the procedure. Ultra sound bio microscopy help us in detection of retroiridal lesions such as ciliary body cysts and lens related angle closure which cannot be assessed by other imaging techniques as anterior segment OCT.