Ultrasonic Evaluation of Ocular Tissues

This study involves the diagnosis of several eye diseases, as follows:

Glaucoma:

1. Morphometry and spectral parameter assays: Clinical correlative studies in primary and secondary glaucoma subgroups: This is a volunteer study to obtain volumetric measurements of age-related changes in the ciliary body and individual ciliary muscle components. The study will provide baseline values for treatment monitoring studies of glaucoma therapeutics. There is minimal risk that the ultrasound procedure may reveal an occult ocular disease process, but the probability is very small. Patients will be informed and assisted in obtaining appropriate care if any abnormality is seen.

2. Morphometry and spectral parameter assays: Ciliary body drug interactions in patients with initial diagnosis of open angle glaucoma: This study will attempt to document changes in anterior segment functional anatomy related to medical management of glaucoma. We hypothesize that several classes of anti-glaucoma drugs produce permanent modification of ciliary muscle vasculature that is related in turn to loss of drug efficacy over time. Data from COAG patients will be compared with age and sex matched normals. Participation in the study will not effect the ongoing glaucoma therapy of patients.

   Accommodation:

3. Accommodative function in young emmetropes and transitional presbyopes: This is a volunteer study to develop a descriptive model of the human eye's focusing mechanism based on ultrasound morphometric measurements and spectral parameter assays. This study will measure dynamic changes in ciliary body spectral assays (size, CQ2) during calibrated accommodative tasks in volunteers with good amplitude of accommodation and those with accommodative loss do to aging and model 3-D conformal changes in anterior segment structures during accommodation. There is minimal risk that the ultrasound procedure may reveal an occult ocular disease process, but the probability is very small. Patients will be informed and assisted in obtaining appropriate care if any abnormality is seen.

   Ocular Tumors

4. Tumors of the iris and ciliary body: This is an observational study of growth pattern changes in anterior melanoma for the purpose of identifying prognostic variables associated with rapid tumor growth. A percentage of small melanomas are observed for periods of up to several years before demonstrable growth will suggest more aggressive treatment. In the clinical ultrasound practice many patients with these tumors are seen at 3 to 6 month intervals to provide the ophthalmic oncologist with updated tumor volume data. We will examine changes in the ultrasound scattering structure of these tumors over time and their correlation with volume changes. The on-going research data are not released as part of the clinical ultrasound report.

   Age-related Macular Degeneration

5. Posterior examinations: age-related macular degeneration: This study will examine the use of higher frequency (20-30 MHz) ultrasound in the early diagnosis of Age-related macular degeneration. Our hypothesis is that early changes in the choriocapillaries and choroid vascular density and conformation can be detected with high-frequency spectral assays. We will obtain ultrasound scans at frequencies of 20 MHz or more, as well as OCT and fundus photographs. Similar numbers of age-matched control subjects will be examined. Measurements of retinal and choroidal thickness profiles in the peri-macular region will be made. Spectral data will be used for morphologic vascular analysis (size and shape). Statistical comparison will be made using parametric and non-parametric methods between control and AMD groups.