Biomedical subjects

Mark T Dunbar

Publications and source records attributed to Mark T Dunbar.

5 recordsLinked to original sources

PubMed2005

Optical coherence tomography: its clinical use for the diagnosis, pathogenesis, and management of macular conditions.

BACKGROUND: Optical coherence tomography (OCT) is a noninvasive, noncontact transpupillary imaging technology that can image retinal structures in vive with a resolution of up to 10 microns. Anatomic layers within the retina can be differentiated and retinal thickness measured. The objective is to demonstrate clinical viability and useful interpretation of macular images derived from a commercially available OCT instrument. METHODS: A Stratus OCT (Zeiss-Humphrey, Dublin, California) imaging system was used to evaluate several pathological presentations of the macula in selected patients. Conditions illustrated in this case series were macular holes, epiretinal membranes, macular edema, idiopathic central serous choroidopathy, detachments of pigment epithelium and sensory retina, choroidal neovascular membranes, and retinal vascular occlusions. CONCLUSIONS: Acquired OCT images achieved structural information regarding anatomical characteristics of the conditions scanned. A cross-sectional resolution of 10 microns was accomplished, which is 10 times greater than current ultrasound. OCT provides important information that may be critical in the diagnosis and management of some ocular conditions. Its high-resolution scans may contribute to the better understanding of disease pathogenesis, as well as assistance in or confirmation of a diagnosis. This imaging technology provides important information beyond what can be seen on clinical examination, and offers a useful adjunct to other diagnostic imaging tools such as fundus photography, fluorescein angiography, and indocyanine green angiography.

Aged↗

PubMed2004

Atypical presentation and review of the ICE syndrome.

BACKGROUND: The different variants of the iridocorneal endothelial (ICE) syndrome were separately described in the early to mid-1900's and were eventually linked to a common etiology of an abnormal corneal endothelium. The ICE syndrome typically manifests in early to middle adulthood, usually occurs in women, and is almost always unilateral. Management of patients with any variant of the ICE syndrome challenges even the best clinicians. CASE REPORT: We present a 52-year-old patient with Chandler's syndrome. Our patient shared many of the classic characteristics of Chandler's syndrome, including peripheral anterior synechiae and corneal edema, with one unusual aspect--the patient was male. Details regarding the subsets of the ICE syndrome, differential diagnosis, and current understanding of the pathophysiology are also reviewed. CONCLUSION: The ICE syndrome is a progressive anterior segment disease that is quite difficult to manage. Corneal edema, increased IOP, and glaucoma are all sequelae of these conditions and, even in the best hands, are extremely challenging to manage. Today, nearly 100 years after Harms described the first patient with an ICE syndrome, we still do not know the exact mechanism for the corneal endothelial changes. Many investigations have been made into the causative agent or stimulus for abnormal endothelial growth in the ICE syndrome. No definitive proof has been established, but a relationship may exist with the Herpes Simplex and Epstein-Barr viruses. Further investigation is needed to determine the most-appropriate treatment and management of the ICE syndrome.

Adrenergic beta-Antagonists↗

PubMed2004

Retinal angiomatous proliferation: clinical characteristics and treatment options.

BACKGROUND: A new form of exudative age-related macular degeneration (ARMD), retinal angiomatous proliferation (RAP), has been described in which neovascularization begins in the deep retina, extends through the subretinal space, and eventually communicates with choroidal neovascularization. METHODS: Case series. RESULTS: Common clinical features of RAP include small multiple intra-retinal hemorrhages, intra-retinal edema, vascularized pigment epithelial detachments (PEDs), and retinal choroidal anastomosis (RCA). Fluorescein angiography (FA) reveals ill-defined, occult choroidal neovascularization. Indocyanine green (ICG) angiography is useful in early stages because 'hot spots' can be detected before clinical or FA characteristics are present. Optical coherence tomography (OCT) is useful in illustrating some of the clinical and FA characteristics. The use of photodynamic therapy (POT), combined with intravitreal triamcinolone injection, was successful in stabilizing the RAP lesion in one case discussed in this report. CONCLUSIONS: Retinal angiomatous proliferation is a newly recognized entity of exudative age-related macular degeneration with its own set of clinical, FA, ICG angiography, and OCT features. Experimental treatments such as the use of PDT combined with intravitreal triamcinolone injection demonstrate potential success with this entity. The biggest hope appears to be anti-angiogenic factors currently in clinical trials for the treatment of exudative ARMD.

Aged↗

PubMed2004

Polypoidal choroidal vasculopathy.

BACKGROUND: Polypoidal choroidal vasculopathy (PCV) is a unique form of occult choroidal neovascular membrane. The clinical presentation and angiographic findings distinguish idiopathic PCV from other known neovascular and choroidal degenerative disorders. The characteristic morphology of PCV includes the presence of a branching network of inner choroidal vessels with terminal aneurysmal dilations. Other key findings include subtle nodular protrusions, which may precede multiple serosanguineous retinal pigment epithelial detachments. If Bruch's membrane is compromised, there is an additional risk of exudative retinopathy or vitreal hemorrhage. CASE REPORTS: Three patients with polypoidal choroidal vasculopathy are described with visual impairment secondary to irregular choroidal vascular lesions producing recurrent subretinal hemorrhages and exudative retinopathy. CONCLUSIONS: The characteristic presentation and clinical course of polypoidal choroidal vasculopathy distinguish it from the typical presentation of age-related macular degeneration and other causes of hemorrhagic and exudative retinopathy. Imaging techniques such as fluorescein angiography, indocyanine green angiography, and optical coherence tomography may assist in the accurate diagnosis of PCV, so that appropriate treatment and management can be provided. In patients who manifest exudative, hemorrhagic retinopathy, with no signs of active inflammation or an anatomic predisposition to choroidal neovascularization, PCV should be considered.

Aged↗

PubMed2002

A cost analysis of the prostaglandin analogs.

BACKGROUND: The efficacy, ease of use, and favorable side effect profile has increased the popularity of the prostaglandin analogs for topical treatment of a variety of glaucoma types. We undertook a cost analysis study of all the prostaglandin analogs. METHODS: Mean number of drops per bottle, mean drop volume, total bottle volume, percent overfill per bottle, mean national bottle cost, daily cost of therapy, and yearly cost of therapy were calculated for all four of the prostaglandin analogs. RESULTS: Yearly cost of monocular therapy was $230.68 for latanoprost, $219.37 for travoprost, $211.34 for bimatoprost, and $178.85 for unoprostone. Unoprostone was by far the least expensive of the prostaglandin analogs tested. Bimatoprost, latanoprost, and travoprost were essentially the same price, varying in yearly cost to the patient by less than twenty dollars. Bimatoprost had the most expensive bottle price, unoprostone the least expensive. Bimatoprost also had the largest percentage of overfill from labeled volume. Unoprostone had the most monocular treatment days per bottle. CONCLUSION: Cost, in addition to efficacy and side affect profile, should be considered when determining which prostaglandin analog to prescribe to glaucoma patients.

Antihypertensive Agents↗