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Biomedical subjects

R Eiferman

Publications and source records attributed to R Eiferman.

7 recordsLinked to original sources
PubMed1994

193-nm excimer photorefractive keratectomy in high myopia.

PURPOSE: To evaluate the refractive results of 193-nm excimer laser photorefractive keratectomy (PRK) performed on 48 highly myopic eyes in a multicenter study. METHODS: A Visx 2015 or 2000 argon-fluoride excimer laser and a single-zone ablation technique were used. Postoperatively, eyes were treated with topical fluoromethalone for up to 5 months. Most eyes were treated with a 6.0- to 6.2-mm beam diameter after undercorrections and increased regression were noted with a 5.5-mm beam in earlier studies. Forty-eight eyes were treated for myopia, which was between -8.0 and -15.25 diopters (D) (spherical equivalent). The mean preoperative refraction was -11.2 D. Retreatment was performed after 6 to 16 months on 11 eyes for undercorrection. All eyes not retreated were followed for at least 12 months. RESULTS: At 6 months, follow-up was available on 47 eyes. Of these eyes, 40% and 64% achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 60% of eyes attained 20/40 visual acuity or better uncorrected. Eleven patients (23%) were retreated between 6 to 16 months for undercorrection and/or regression. After retreatment, 47% and 81% of eyes achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 15% of eyes lost two lines of best-corrected visual acuity, and no eyes lost more than two lines. There was slightly more corneal haze seen in this group compared with the haze seen in patients undergoing PRK for low and moderate myopia. CONCLUSIONS: These data show that excimer PRK can correct high amounts of myopia with reasonable stability after 6 months. Excimer PRK is an effective surgical treatment of severe myopia, but long-term follow-up is still needed to assess the stability of its effect.

Adult↗
PubMed1992

Growth factors and corneal endothelial cells: III. Stimulation of adult human corneal endothelial cell mitosis in vitro by defined mitogenic agents.

Human corneal endothelial cells (HCEC) do not mitose extensively in vivo after damage to the endothelial layer. However, HCEC will divide in vitro if cultured under appropriate conditions. We measured the ability of various sera, plasma, growth factors, and nutritional substances to stimulate mitosis of HCEC during 5 days of organ culture after a central freeze injury to the endothelium. Supplementation of a chemically defined medium (CDM) with 20% fetal human serum (FHS) induced significantly higher numbers of mitotic figures or labeled nuclei of human or cat corneas compared with paired corneas cultured in CDM alone. Furthermore, addition of 20% FHS produced more labeled nuclei than did addition of 20% fetal bovine serum or 20% adult human serum. Dialyzed fetal human serum failed to stimulate mitosis, indicating that one or more components of fetal human serum with molecular weight less than 12,000 are essential for mitosis. Human plasma also failed to stimulate mitosis, but an extract of human platelets significantly stimulated high levels of nuclear labeling, suggesting that growth factors contained in platelet granules were responsible for serum-stimulated mitosis of HCEC. Addition of 100 nM epidermal growth factor (EGF) or 10 microM insulin to CDM supplemented with low levels of adult human serum (0.5%) stimulated significantly higher numbers of labeled nuclei compared with paired corneas cultured with 0.5% adult human serum. Supplementation of corneal storage media (K-Sol and CSM) with a mixture of chemically defined agents consisting of EGF, insulin, transferrin, selenium, linoleic acid, and albumin stimulated significantly higher numbers of labeled nuclei compared with paired corneas cultured in the unsupplemented corneal storage media.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

The use of the 193-nm excimer laser for myopic photorefractive keratectomy in sighted eyes. A multicenter study.

Photorefractive keratectomy was performed at three centers using the 193-nm excimer laser on 31 sighted myopic eyes. Preoperative refractive errors (spherical equivalent) ranged from -12.00 to -4.00 diopters (D) (mean, -6.49 +/- 1.75 D). Peribulbar anesthesia, a 5.2- to 6.0-mm beam diameter, and topical corticosteroids were used for up to 6 months after surgery. The epithelium healed within 3 to 4 days, and all patients returned to their best corrected visual acuity within 1 line of their preoperative acuity. There was minimal subepithelial reticular haze, peaking at 3 weeks and diminishing over the next 3 to 4 months, which was not felt to be visually significant. At 6 months, the average residual refractive error was -1.85 +/- 2.5 D. Sixty-eight percent of eyes were corrected within 2 D and 55% within 1 D of attempted correction. There was no significant change in astigmatism, contrast sensitivity, corneal sensation, or endothelial cell counts. This preliminary work shows that photorefractive keratectomy has promise in the reduction of moderate myopia.

Adult↗
PubMed1977

Effect of the ophthalmic preservative thimerosal on rabbit and human corneal endothelium.

Widespread use of the mercurial-containing preservative thimerosal as an antibacterial agent in ophthalmic drugs and solutions warranted an investigation into its possible cytotoxic effects on the functional and ultrastructural integrity of the corneal endothelium. No changes in corneal thickness were observed during 5 hours' perfusion of the endothelium of rabbit and human corneas with 0.0001 and 0.0005 percent thimerosal in glutathione bicarbonate Ringer's solution (GBR). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of the endothelium of the 0.0001 percent group revealed normal ultrastructure. SEM and TEM of the endothelium of corneas perfused with 0.0005 percent thimerosal for 5 hours revealed condensed mitochondria, cytoplasmic vacuoles, and cytoplasmic flaps at the apical end of the cellular junctions. Perfusion of higher concentrations (0.001 and 0.005 perecnt) of thimerosal in GBR resulted in increases in corneal thickness after 2 hours and irreversible ultrastructural damage to the endothelial cells by 5 hours. Corneas perfused with 0.01 and 0.1 percent thimerosal in GBR showed a rapid and immediate increase in corneal thickness and endothelial cell death and necrosis within 1 hour. It is postulated that the mercury in thimerosal becomes bound to the cell membrane protein sulfhydryl groups, causing an increase in cellular permeability; These results suggest that the prolonged exposure of the corneal endothelium to thimerosal in the accepted antimicrobial dosage of 0.005 to 0.001 percent may result in functional and structural damage to the endothelium.

Animals↗