Dentistry for the 21st century? Erbium:YAG laser for teeth.

The first dental laser for use in cutting human teeth in vivo was cleared by the Food and Drug Administration for marketing in the United States. The authors explored, in summary form, the data provided to the FDA for the clinical use of the erbium:yttrium-aluminum-garnet, or Er:YAG, laser. The authors concluded that using the Er:YAG laser to treat dental hard tissue is both safe and effective for caries removal, cavity preparation and enamel etching.

Treatment of myopic astigmatism with the 193 nm excimer laser utilizing aperture elements.

In this paper, we examine the 193 nm excimer laser's efficacy and safety in treating myopic astigmatism. The VISX Twenty/Twenty excimer laser uses aperture elements to effect astigmatic photorefractive keratectomy. In 70 patients with six months follow-up, the average postoperative sphere was -0.14 and the average postoperative cylinder was -0.54. Seventy-one percent of these patients had uncorrected visual acuity of 20/40 or better at six months. In 12 patients with one year follow-up, the average postoperative sphere was -0.05 and the average postoperative cylinder was -0.59. Eighty-three percent of these patients had uncorrected acuities of 20/40 or better; none had a clinically significant loss of best corrected acuity. This investigation demonstrates that the excimer laser can be used to treat myopic astigmatism successfully.

Biofeedback and functional electric stimulation in stroke rehabilitation.

The study examined the efficacy of functional electric stimulation (FES) and biofeedback (BFB) treatment of gait dysfunction in patients with hemiplegia after stroke. These two therapeutic modalities were tested alone and in combination in a prospective, controlled, randomized trial. The authors hypothesized that in concurrent use, these two modalities would complement one another. Thirty-six hemiplegic patients undergoing rehabilitation after stroke were accepted for study and randomized into four groups to receive either control, FES, BFB, or combined therapies. Each patient received 30 minutes of treatment three times per week for six weeks, in addition to their general rehabilitation program. Quantitative gait analysis was performed biweekly on each subject during the experimental therapy and for four weeks afterward. Thirty-two subjects completed the study. Combined therapy with BFB and FES resulted in improvements in both knee and ankle minimum flexion angles during swing phase that were statistically significant with p = 0.05 and p = 0.02, respectively. Velocity of gait, cycle time, and symmetry of stance phases also improved. The length of time elapsed since the stroke did not prove to be a significant factor.

Fine tuning of swing phase of hydraulic knees using gait laboratory.

Recent technologic advances now permit instant gait analysis, making clinical use of the gait laboratory feasible. In this study, the ambulation of two amputees with hydraulic knee prostheses is evaluated by measuring ground reactive forces and by tracking the motion of lights attached to limb segments. A PDP 11/34 minicomputer records, integrates, and processes data received from an 8-channel force plate and from two high-speed solid-state array cameras. Information in the form of ground reactive forces, angular displacements and angular velocities of normal and prosthetic limbs is displayed on a monitor and graphed on an X-Y plotter. Adjustments are made immediately to the hydraulic mechanism so that optimal function of the prosthetic equipment can be objectively determined.

A longer view of secondary intraocular lens implantation with special emphasis on the role of the vitreous.

In a series of 50 patients undergoing secondary implantation of a Choyce-style anterior chamber lens, 43 (86%) had regained or improved their best corrected preoperative vision by the third postoperative month. Four eyes had intraoperative vitreous loss, one resulting in subchoroidal hemorrhage and another associated with CME. Of the four cases of CME, three had regained or improved their best corrected preoperative acuity by the eighteenth postoperative month.

The effect of phacoemulsification on the corneal endothelium.

Endothelial cell densities were measured following intracapsular cataract extraction and phacoemulsification in the same patients. Phacoemulsification caused 29 percent more endothelial cell loss than intracapsular cataract extraction (p less than .001). The degree of endothelial damage with phacoemulsification appeared to be age related and was minimal in the younger patients.