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Biomedical subjects

B Sand

Publications and source records attributed to B Sand.

6 recordsLinked to original sources
PubMed1993

Holmium laser thermokeratoplasty.

PURPOSE: Corneal curvature can be altered by shrinking stromal collagen with a pulsed solid-state holmium: YAG laser in a procedure termed laser thermokeratoplasty. METHODS: The authors performed laser thermokeratoplasty in 40 human cadaver eyes using a ring pattern of 32 spots, each spot having a diameter of 300 microns. RESULTS: The amount of induced corneal steepening decreased as ring diameter was increased in 1 mm increments, with 22.2 +/- 3.3 and 3.7 +/- 2.0 diopters (D) of central steepening with diameters of 3 and 7 mm, respectively. Results of histologic examination showed a cone-shaped zone of increased stromal hematoxylin uptake extending posteriorly for 90% of stromal thickness. Energy levels greater than those needed to induce topographic changes produced limited endothelial injury in rabbit corneas and, in some cases, intraocular inflammation. A computerized, finite element model of the globe demonstrated central corneal steepening as a result of heat-induced stromal contraction to a depth of 75% corneal thickness. CONCLUSIONS: These data support previous studies indicating that central corneal topography can be modified by heating corneal stroma in a controlled fashion with the mid-infrared holmium:YAG laser.

Animals↗
PubMed1987

Lactoferrin and serum albumin in the conjunctival fluid of eyes operated for senile cataract.

The concentrations of serum albumin (SA) in the conjunctival fluid were measured in 25 patients before surgery and in the post-operative period following cataract extraction. We found a significant increase in mean tear fluid SA concentration on the first post-operative day. The SA concentration remained high during the first 3 pre-operative levels. No correlation between the post-operative concentration profile of tear fluid SA and earlier findings of the tear lactoferrin (LF) profile of the same group of patients (Jensen et al. 1985) could be shown, although a trend towards an inverse relationship was apparent from the graphs. Pre-operatively, we found a significant positive correlation between age and concentration of SA in the conjunctival fluid (P less than 0.05) which might be interpreted as an increase in leakage from conjunctival vessels with age. This would, at least partly, explain the decreasing LF concentration with age (Jensen et al. 1986; McGill et al. 1984). It is concluded that transudate/exudate from the conjunctival vessels, represented by the change in the SA concentration in the conjunctival fluid, might be responsible for an initial post-operatively reduced concentration of LF and possibly other lacrimal gland proteins.

Adult↗
PubMed1986

Changes in the concentration of secretory immunoglobulin A in tears during post-operative inflammation of the eye.

Twenty-five patients operated for cataract were examined for secretory immunoglobulin A (sIgA) content of tears by an enzyme-linked immunosorbent assay technique. The patients were examined before operation and throughout the post-operative period. The pre-operative level was 795 micrograms/ml, significantly dropping on the first post-operative day to 461 micrograms/ml. Thereafter the level increased to pre-operative value, and finally decreased once more to half the pre-operative level on the 12th post-operative day. The first drop in sIgA concentration is proposed to be a dilution effect by a significantly increased tear volume as determined by the Schirmer test. The reason for the second drop is up to now unexplained, but might be the result of an exhaustion of the sIgA production by the tear glands.

Cataract Extraction↗