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Biomedical subjects

S R Waltman

Publications and source records attributed to S R Waltman.

At least 19 recordsLinked to original sources
PubMed1979

Refractive variation and donor tissue size in aphakic keratoplasty. A prospective randomized study.

Forty-six patients were examined in a prospective, randomized clinical study to compare the use of the same size trephine on both donor and recipient with the use of a 0.5-mm larger trephine on the donor in aphakic keratoplasty and in keratoplasty combined with lens extraction. The results showed no statistically significant difference in refractive error, either in spherical equivalents or in astigmatism. The larger donor tissue may have some value in reducing high plus-refractive error and in reducing intraocular pressure after surgery.

Aphakia↗
PubMed1979

Vitreous fluorophotometry in adult-onset diabetes mellitus.

We studied the breakdown of the blood-retinal barrier in 83 patients with adult-onset diabetes mellitus, by using vitreous fluorophotometry. The patients were in good stable metabolic control and were receiving injectible insulin or oral hypoglycemic agents. Vitreous fluorophotometry readings were abnormally high but similar in both groups of patients, and no significant differences were found between those with and those without early background diabetic retinopathy. Significantly more patients taking oral agents were hypertensive, and significantly fewer of these patients had background retinopathy.

Adult↗
PubMed1979

Vitreous fluorophotometry in diabetes mellitus.

Vitreous fluorophotometry has proved to be a useful method to evaluate the integrity of the blood-ocular barrier to fluorescein in clinical and experimental diabetes mellitus. Diabetic patients with or without background retinopathy had increased vitreous accumulation of fluorescein after intravenous injection when compared with age-matched controls. Streptozotocin-induced diabetes in rats increase vitreous fluorescein levels. In the rat, this abnormality was reversed with insulin therapy and with pancreatic islet transplantation. The breakdown of the blood-ocular barrier to fluorescein appears to be the earliest detectable ocular abnormality of diabetes.

Adult↗
PubMed1979

Ocular fluorophotometry in streptozotocin diabetes mellitus in the rat: effect of pancreatic islet isografts.

Fluorophotometry was used to evaluate the integrity of the blood-ocular barriers to fluorescein in experimental diabetes mellitus in rats. This technique allowed quantitation of ocular fluorescein concentrations following intravenous injection. Streptozotacin-induced diabetes resulted in an increased fluorescein accumulation in the anterior chamber (1.52 +/- 0.17 microgram/ml, mean +/- S.E.M.) and vitreous (0.82 +/- 0.11) over baseline nondiabetic levels (0.68 +/- 0.80 and 0.40 +/- 0.03, respectively). Fluorophotometry was repeated at 5, 13, and 20 days following portal vein pancreatic islet transplantation. At 5 days anterior chamber (1.40 +/- 0.17) and vitreous (0.61 +/- 0.08) fluorescein concentrations remained elevated. However, at 13 and 20 days following islet transplantation, ocular fluorescein concentrations were identical to levels observed prior to the induction of diabetes. Intravenous glucose (0.5 gm/kg) tolerance testing was performed 5 and 13 days following transplantation. The glucose responses to the tolerance test were normal and similar at both times. However, at 5 days the insulin response was abnormal with a decreased initial peak and an absent second peak. At 13 days there was a normal biphasic insulin response. In experimental diabetes mellitus ocular vascular permeability was more closely correlated with insulin than blood glucose abnormalities.

Animals↗
PubMed1979

Effects of therapy on vitreous fluorophotometry in diabetes mellitus.

Quantitative vitreous fluorophotometry was used to study the alteration of the blood-retinal barrier in 116 patients with diabetes mellitus of adult onset. The patients were in good stable metabolic control on injectable insulin, oral hypoglycaemics, or diet therapy. Vitreous fluorophotometry readings were abnormally high but similar in all three groups and in those with or without early background retinopathy. A higher incidence of systemic hypertension was noted in those patients requiring oral agents compared to those on insulin or diet therapy.

Biological Transport↗
PubMed1979

Size of donor corneal button and outflow facility in aphakic eyes.

Outflow facility was measured in 6 human eye bank eyes following penetrating keratoplasty and cataract extraction. A 7.5 mm corneal button was removed and replaced by an 8 mm button using conventional mid-to-deep stromal sutures. Baseline outflow facility in the phakic eyes (0.28 +/- 0.12 microliter/min/mm Hg, mean +/- SD) was unchanged (0.29 +/- 0.12) following the cataract extraction and penetrating keratoplasty using the larger corneal button.

Aphakia, Postcataract↗
PubMed1979

Intraocular pressure after aphakic penetrating keratoplasty "through-and-through" suturing.

Our clinical study was designed to determine whether "through-and-through" corneal sutures would prevent the postoperative intraocular pressure rise that occurs in 70% of aphakic eyes after uncomplicated penetrating keratoplasty. Twenty-five aphakic patients received the same operative procedure except that the corneal buttons of ten of them were sutured into place with "through-and-through" sutures. The intraocular pressures of patients with the "through-and-through" sutures were significantly lower than those of the other patients during the entire postoperative course.

Aphakia, Postcataract↗
PubMed1979

Modified M-K medium for human penetrating keratoplasty.

A series of 120 consecutive human penetrating keratoplasties was performed using modified McCarey-Kaufman (M-K) medium. The medium has ben altered by changing the buffer system, adding a pH indicator, and using a different antibiotic from that originally formulated. There were no cases of primary donor failure and 95 per cent clear grafts after 1 year.

Adult↗
PubMed1979

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.

Adult↗
PubMed1978

The effect of suture depth on outflow facility in penetrating keratoplasty.

Outflow facility was measured in human eye bank eyes following penetrating keratoplasty (PKP) and cataract extraction. After measuring baseline outflow facility, a PKP and lens extraction was performed with the corneal button replaced by both interrupted "through-and-through" sutures and a conventional mid-to-deep stromal running suture. Outflow facility was unchanged from baseline with both sutures. However, following removal of through-and-through sutures outflow facility decreased 37%. This same suturing procedure was repeated in a second group of phakic eyes in which suture depth did not influence outflow facility.

Cataract Extraction↗
PubMed1978

Vitreous fluorophotometry in juvenile-onset diabetes mellitus.

Vitreous fluorophotometry was carried out in 99 juvenile-onset, insulin-dependent diabetics and 31 control subjects. The mean vitreous fluorescein concentration one hour after intravenous administration of fluorescein, 7 mg/kg, was 5.4 +/- 0.3 ng/ml (mean +/- SEM) for controls and 9.5 +/- 0.4 ng/ml for diabetics (P less than .005). Diabetic patients with or without background retinopathy, when randomly matched for age or duration of their disease, had similar vitreous fluorophotometry measurements. The break-down of the blood-retinal barrier to fluorescein appears to be the earliest detectable ocular abnormality of diabetes.

Adolescent↗
PubMed1978

Endothelial cell loss in intraocular lens placement.

Endothelial cell counts were done on eyes selected to fall into four categories: unoperated, intracapsular cataract extraction without implantation, and intracapsular cataract extraction with easy or difficult insertion of an intraocular implant. Uncomplicated cataract extraction resulted in less than 9% cell loss. Implantation in "easy" eyes resulted in 12% cell loss (p greater than 0.3). Eyes in which implantation was difficult suffered an average loss of 65% of the endothelial cells (p less than .001). The reasons for cell loss are discussed and some improvements in techniques are mentioned with examples of the value of analysis of motion picture records of the surgery. The obvious lesson to be learned is that everything possible must be done to optimize routinely the conditions for lens implantation. The surgeon who finds conditions unfavorable for lens implantation must consider that persistence will mean sacrificing, on the average, two-thirds of the corneal endothelial cells.

Cataract Extraction↗