Biomedical subjects
Publications and source records attributed to D D Michaels.
A comparison of spheric and aspheric cataract lenses was carried out on 28 patients with uncomplicated surgery. Lenses were evaluated with respect to eccentric acuity, visual field, ring scotoma, magnification, distortion, and subjective preferences. The results suggest that design differences can be applied to specific visual tasks, thus improving clinical lens prescribing.
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Indications for spectacle correction are reviewed in the context of symptoms, pathophysiology, and prognostic efficacy. Criteria include improving acuity, restoring comfortable vision, enhancing visual efficiency, preventing progression, and assorted miscellaneous goals. Alternatives to spectacles and side effects are analyzed. Specific guidelines for individualized management are evaluated in terms of current research.
Prescribing vertical prisms not infrequently leads to unsightly spectacles at best, and computing them may lead to errors at worst. Prismatic compensation for a particular reading point is of little value when the patient uses other eccentric portions of the lens, and it is not necessary if the patient learns to use (or continues to use) the optical centers. Clinical evaluation of eye-head posture and vertical phorias may reveal tell-tale clues in managing vertical imbalances in general and the anisometropic presbyope in particular.