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H R Atta

Publications and source records attributed to H R Atta.

At least 19 recordsLinked to original sources
PubMed2005

Ultrasound biomicroscopy in deep sclerectomy.

PURPOSE: To evaluate by ultrasound biomicroscopy (UBM) the anatomical characteristics and the intraocular pressure (IOP) lowering mechanisms of deep sclerectomy after long-term follow-up. METHODS: In all, 22 eyes of 21 consecutive patients who had deep sclerectomy were examined by UBM. Several UBM variables were prospectively evaluated, including the presence and maximum length and height of the intrascleral space, the minimum thickness of residual trabeculo-Descemet membrane (TDM), the presence and type of subconjunctival filtering bleb, and the presence of other possible drainage sites, for example suprachoroidal. Surgical success was considered to be achieved when the IOP was <22 mmHg and the IOP was lowered by more than 20% without the use of any medication. The possible association between UBM variables and the surgical outcome was determined. RESULTS: The mean time between surgery and the UBM examination was 12.0+/-5.3 months. The mean IOP decreased significantly from a preoperative value of 23.7+/-4.0 to 16.0+/-3.9 mmHg at the time of UBM (P<0.01). There was a poor correlation between the level of IOP at the time of UBM and the length of intrascleral space (r2=0.0016), the height of the intrascleral space (r2=0.136), or the thickness of remaining TDM (r2=0.0009). The presence and type of filtering bleb were not associated with the success. CONCLUSIONS: In patients undergoing deep sclerectomy, UBM examination after long-term follow-up showed the presence of an intrascleral space and a filtering bleb in most patients. The surgical outcome was not associated with the UBM variables of the surgical area.

Descemet Membrane↗
PubMed2004

A comparison of 10 MHz and 20 MHz ultrasound probes in imaging the eye and orbit.

BACKGROUND: /aims: B-scan ultrasonography is an invaluable, versatile, non-invasive tool in ophthalmology. Recently, a "high frequency" contact 20 MHz probe has been introduced. B-scanning ultrasonography of orbital and ocular structures was performed with both a 10 MHz and the new 20 MHz probe, to evaluate what information was best obtained from each probe, and provide recommendations for the use of each. METHODS: Patients were selected from routine ultrasound clinics at Aberdeen Royal Infirmary between 1 January 2002 and 1 August 2002. The vitreous, retina, choroid, sclera and, in the orbit, the extraocular muscles, optic nerve, and orbital fat were assessed with both the 10 MHz and 20 MHz probes. In the laboratory, using a "point target," the characteristics of the ultrasound beam at different distances from the probe were also assessed. RESULTS: The point target showed that focus was deeper and that the lateral, and to a lesser degree the axial, resolution are sharper with the 20 MHz probe, compared with the 10 MHz probe. In patients' eyes, highly reflective structures are seen at higher resolution with the 20 MHz probe. Imaging of lower intensity reflectors such as the vitreous and particles within it are seen better with the 10 MHz probe. Increased tissue attenuation was evident with the 20 MHz probe. CONCLUSION: The 20 MHz probe has a superior resolution and can be used to better detect details at the posterior pole and in the orbit. The 10 MHz probe can be used to examine low intensity scatterers, such as the vitreous humour, that cannot be seen using a higher frequency probe.

Eye↗
PubMed2000

Role of ultrasound biomicroscopy in managing pseudophakic pupillary block glaucoma.

We describe a case of anterior capsule adherence to the iris that occurred after phacoemulsification with in-the-bag intraocular lens (IOL) implantation. This adherence led to the development of pseudophakic pupillary block glaucoma. There were no synechias at the pupillary margin associated with the capsule-iris adherence. Ultrasound biomicroscopy, used to evaluate the anterior segment in vivo, clarified the mechanism of pseudophakic pupillary block. The pupillary block was relieved by a single laser iridotomy.

Aged↗
PubMed1999

Ultrasonic localization of anesthetic fluid in sub-Tenon's, peribulbar, and retrobulbar techniques.

PURPOSE: To determine the distribution of anesthetic fluid during 3 regional anesthetic techniques routinely used for phacoemulsification. METHODS: Patients having routine cataract extraction by phacoemulsification were studied after informed consent had been obtained. B-scan ultrasonography was performed on the eye before administration of the anesthetic agent. Kinetic echography was used to scan the eye during administration of the anesthesia to show the needle position and location of fluid in the orbit during the injection. Ten minutes after injection, another scan was performed to outline the pattern of fluid distribution. RESULTS: In all patients, the needle and the anesthetic fluid were seen on ultrasonography, with sub-Tenon's the most easily seen. In the sub-Tenon's group, fluid tracked behind the globe in the retrobulbar space, appearing as a dark outline during the injection. The fluid around the optic nerve developed a characteristic T sign. In the retrobulbar technique, the needle was less easily identifiable and fluid localized within the cone. The fluid distributed in the intraconal fat. Identification of the peribulbar needle and fluid was also more difficult; the fluid was, however, seen in the extraconal fat. After 10 minutes, fluid was seen within the cone. CONCLUSION: B-scan ultrasonography was a suitable method of identifying the needle position and the distribution of anesthetic fluid in regional ocular anesthesia. The sub-Tenon's technique appears to be the safest method of introducing anesthetic fluid into the retrobulbar space without the potential complications of sharp-needle techniques.

Anesthesia, Local↗
PubMed1996

Ultrasonography of the optic disc cup in discs of various sizes.

PURPOSE: The aim of the study was to evaluate the sensitivity of modern, eye-medicated B-scanners in detecting optic disc cups and to correlate the echographic measurements with an optical assessment. A secondary aim was to correlate the rim-to-rim diameter of the optic disc and the width of the retrobulbar optic nerve on standardised A-scan. METHODS: A prospective study was conducted on 25 emmetropic subjects (50 eyes) with discs and cups of various sizes. They were examined optically by one observer using a high-magnification slit lamp and the 90 D Volk lens. Another observer measured the B-scan dimensions of the disc cups and the retrobulbar optic nerve. Data from the two observers were compared at the end of the study. RESULTS: High resolution B-scan detected optic disc cups of 0.5 mm or larger in all cases. A statistically significant correlation was obtained between echographic measurements and both vertical optical cup disc diameters and cup disc (C:D) ratios (p < 0.0001). Large C:D ratios (0.6 or larger) but small rim-to-rim disc diameter were reported as 'small' on echography. No correlation was found between the measurement of retrobulbar nerve and the diameter of the vertical optical disc diameter. CONCLUSION: Modern, eye-dedicated ultrasonographic scanners are capable of detecting optic disc cups of 0.5 mm or larger. As there is a normal variation in optic disc rim-to-rim diameter, and this cannot be measured using ultrasound, we suggest the reporting of a C:D ratio on the ultrasonography to be potentially misleading. Large disc cups are, however, easily seen and many are likely to be 'pathological'.

Adult↗
PubMed1996

Venous stasis orbitopathy: a clinical and echographic study.

AIMS: A variety of acute and chronic orbitopathies may be distinguished by standardised echography. Venous stasis orbitopathy (VSO) often presents with orbital signs when secondary to cavernous sinus and middle cranial fossa disorders. In this study, the aim was to assess whether differentiation between vascular and nonvascular causes of VSO could be made on the basis of clinical and echographic features at the time of presentation. METHODS: This study comprised 37 patients with echographic features of VSO (17 patients with arteriovenous fistulae, confirmed by computed tomography imaging or angiography, and 20 patients with non-vascular diseases). Excluded were patients with orbital mass lesions detected by echography and muscle enlargement due to other causes (for example, orbital myositis). Patients with a suspected mass involving the orbital apex and echographic features of VSO were included. After full neuro-ophthalmic and ocular examination, both orbits were examined to document maximal thickness and reflectivity of four recti muscles and compared with the normal contralateral orbit with standardised A-scan (Kretz-technik 7200MA or Ophthascan) and contact B-scan (Ultrascan or Ophthascan S). RESULTS: Cumulative ocular recti muscle thickness was significantly greater in patients with arteriovenous fistulae compared with the non-fistula group (23.3 (SD 3.7) and 17.8 (2) mm, p = 0.001). Clinically, the presence of a bruit and a uniocular rise in intraocular pressure were significantly greater in the fistula group of patients. CONCLUSIONS: Standardised echography is a safe and non-invasive method of diagnosing VSO in patients presenting with signs of proptosis, ophthalmoplegia, and inflammation of the conjunctiva. Furthermore, using these standard techniques the two major causes of VSO (arteriovenous fistulae and compressive mass lesions) could be differentiated.

Aged↗
PubMed1995

Ultrasonographic investigation of optic neuritis.

A pilot echographic study was conducted to determine the incidence and severity of optic nerve swelling in acute 'idiopathic' optic neuritis and to examine cerebrospinal fluid dynamics in the subarachnoid space, employing the method of standardised echography and the '30 degrees test'. An attempt was made to correlate the degree of nerve swelling with the initial visual loss and with the rate and extent of recovery of vision. The visual function and echographic features of the optic nerve in 27 patients with the diagnosis of acute optic neuritis were assessed with standardised echography. A significant increase in nerve diameter was found in 74% of cases. There was a correlation between nerve swelling and the severity of initial visual loss. The authors conclude that standardised echography is a useful tool in the diagnosis of optic neuritis and may play a role in predicting the visual outcome.

Adolescent↗
PubMed1992

Echographic diagnosis of advanced Coats' disease.

Standardised echography was utilised to diagnose two cases of advanced Coats' disease. The characteristic acoustic features included extensive, poorly mobile retinal detachment; dense, dispersed subretinal opacities; looping of peripheral retina and absence of solid mass lesion and calcification. As enucleation of two eyes was necessary, it has proved possible to correlate the echographic and histological findings of this disease. The echographic features of other common causes of leukocoria are also discussed.

Electroretinography↗
PubMed1990

Ophthalmopathy in early thyrotoxicosis--relationship to thyroid receptor antibodies and effects of treatment.

A prospective study of 25 newly diagnosed thyrotoxic patients was undertaken to determine the incidence and severity of ophthalmopathy in the early stages of the disease. A quantitative analysis of the ocular muscle changes was made using B scan ultrasonography, and the effects of treatment for the thyroid disease on the course of the eye changes was assessed. Although the majority (75%) of patients showed only mild clinical signs of ophthalmopathy (Werner Class 3 or less), 92% had ultrasonographic evidence of ocular muscle enlargement. Clinical involvement of the extraocular muscles was seen in 12% of the cases. There was an inverse correlation between the serum level of thyroid stimulating hormone receptor antibody (TR Ab) and the size of the extraocular muscles. Recovery of the euthyroid state with treatment was accompanied by a decrease in orbital infiltration in some cases, both clinically (reduced amplitude of intraocular pressure rise on elevation of the globe) and by ultrasonography, but the improvement was not statistically significant.

Adolescent↗
PubMed1988

The findings of standardized echography for choroidal folds.

Twenty-four patients (31 eyes) with choroidal folds unassociated with orbital tumors were evaluated with standardized echography. Hypermetropia was the most commonly associated finding (eight eyes); in ten eyes, no consistent abnormal findings could be established. Among the less common causes were swelling of the optic nerve proper or the perineural sheaths and thickened extraocular muscles. Standardized echography demonstrated ocular changes, orbital changes, or both, in all but two patients (two eyes) with idiopathic folds. The most frequent findings were flattening of the posterior ocular wall (18 eyes), thickening of the retinochoroid layer (12 eyes), and distention of the optic nerve sheaths (eight eyes). While fluorescein angiography is well established as the preferred method of demonstrating choroidal folds, standardized echography may now be used to delineate the often subtle associated ocular and orbital findings.

Adult↗
PubMed1988

Imaging of the optic nerve with standardised echography.

Standardised echography is a unique method of ophthalmic ultrasound that requires special instrumentation, well prescribed methods of examination and a high level of operator skill. Because of its anatomical features and position in the orbit, the optic nerve is well suited for imaging by this technique, particularly for the detection of subtle lesions in its anterior portion and nerve head. Standardised A-scan can measure precisely the width of the nerve, differentiate between fluid and solid lesions as a cause of nerve swelling (the 30 degree test) and, by examining reflectively and internal structure, provide "ecographic tissue diagnosis" in a high proportion of cases. Contact B-scan is suitable for detecting lesions of the optic disc (drüsen, swelling and large cupping), calcification in the nerve (meningioma, deep drüsen), and for the topographic display of lesions. CT-scan is superior in displaying the apical and intra-cranial portion of the nerve, and the simultaneous presentation of both orbits, peri-orbital structures and bony walls.

Adult↗