MRI of the normal orbit and optic pathway.

In recent years MRI has made increasingly important contributions to the evaluation of the orbit and optic pathway. The unique ability of MRI to demonstrate soft tissue contrast allows exquisite demonstration of anatomic detail. MRI technique and normal anatomy are reviewed. Today, optimal ophthalmologic work-up is often incomplete without the critical input of the radiologist.

A comparison of ciliary sulcus and capsular bag fixation of posterior chamber intraocular lenses.

We compare indications, advantages, and disadvantages of ciliary sulcus and lens capsular bag (lens capsular sac) fixation of posterior chamber intraocular lenses (IOLs). Our findings suggest that, whenever possible, it is efficacious to implant the loops of posterior chamber IOLs within the capsular bag. This positions the lens optic and the supporting loops in the natural anatomical position, sequestered from highly vascular uveal tissue and the blood aqueous barrier. This should minimize the potential for complications that may be associated with iris-ciliary body contact. Considering the rapid increase in the number of implantations of IOLs now being performed (approximately 700,000 per year in the United States alone), a possible reduction of even 1% in clinically significant complications would make this effort worthwhile. Widespread application of in-the-bag implantation is predicated on the assumption that the surgeon is proficient with this procedure and that careful follow-up of patients does not reveal any significantly increased incidence of lens dislocation due to zonular rupture.

Physiology and pharmacology of aqueous humor inflow.

Recent physiological and pharmacological data pertinent to aqueous humor inflow regulation have been reviewed. New anatomical and electrophysiological data are presented, particularly related to aqueous humor secretion. The action of adrenergic agonists and antagonists is discussed in relation to changes in intraocular pressure, and the effects of a variety of experimental perturbations is presented. The multiple factors which affect aqueous humor inflow are discussed in the context of an evaluation of recent pertinent literature.