Edward W. Purnell

Subretinal Neovascularization after Focal Argon Laser for Diabetic Macular Edema

The authors reviewed four cases of iatrogenic subretinal neovascularization after focal argon green photocoagulation for clinically significant diabetic macular edema. An inappropriate combination of small spot size with a high-power setting is the common feature in each case of iatrogenic subretinal neovascularization. Close follow-up with fluorescein angiography is used to identify iatrogenic subretinal neovascularization at an early, treatable stage. All four patients responded favorably to laser photocoagulation of the subretinal neovascular membrane.

Subretinal Neovascularization Following Rubella Retinopathy

A 17-year-old girl and an 11-year-old girl with rubella retinopathy had decreased vision in one eye secondary to subretinal neovascularization and hemorrhage. In both cases a disciform scar with permanent decrease in central vision resulted.

Relative Frequency of Ultrasound Diagnoses in Patients Referred for Ophthalmic Ultrasound

An ultrasound diagnostic coding system was developed that permitted entry of diagnoses into a programmable calculator, thus permitting rapid information retrieval of patients with a specific diagnosis or diagnoses as well as the number of patients with a specific diagnosis. Cataract, vitreous opacity, trauma, choroidal disease, and retinal detachment were the most common diagnoses made. Only 7.2% of the patients had a normal ultrasound, indicating that ultrasound examination is a test probably underutilized by ophthalmologists.

High Resolution Imaging of Filtered Ultrasonic Echo Responses

Several years ago we developed a high resolution ultrasonic B-scanner for general purpose diagnosis, but specifically oriented for use in ophthalmology.1 In the special case of ophthalmology, high resolution is necessary because of the small size of the eye and the amount of detail required for the diagnosis. High axial resolution (.3mm) was achieved through the use of wideband transducers operating at a nominal frequency of 10MHz. Adequate lateral resolution (approximately 1mm) resulted through the use of focused ultrasonic beams.

High Resolution Instantaneous U1trasonic Spectrum Analysis I: Theoretical Considerations

Several researchers are attempting to use Ultrasonic Spectroscopy as an aid to diagnosis thruugh tissue characterization (1,2) Users of ultrasonic spectroscopy seek to develop ultrasonic tissue signacures or fingerpring spectra of the wide variety of normal and abnormal tissues that can exist in the human body. In addition, fundamental relations between the tissue structure and its ultrasonic frequency response are being sought.

Ultrasonic Findings in Diabetic Vitreoretinopathy

The purpose of this study is to demonstrate by serial ultrasonography the course of the vitreoretinal disease of diabetes, to determine what information may be obtained from ultrasonic evaluation and whether ultrasonic examination can predict remissions or exacerbations. The ultimate goals are to evaluate ultrasonography as a method for determining the advisability of vitrectomy in these eyes and to determine the role of ultrasound in the planning and execution of the vitrectomy procedure.

Posterior Ocular Curvature by B Scan Ultrasonography

Analysis of the posterior curvature of the eye on B sector scan ultrasonography is an important parameter in the evaluation of normal and abnormal ocular conditions. In the normal eye, as sound waves pass through the crystalline lens they are refracted producing a well known artifactual change in its posterior curvature making it appear more concave and anteriorly displaced. The magnitude of this refractive effect is greatest as the distance from the crystalline lens increases and thus it is best studied in myopic eyes in which the axial length is greater.