Delmar R. Caldwell

A limited comparison of Apraclonidine's dose response in subjects with normal or increased intraocular pressure

We performed a multicentered, placebo-controlled, randomized, crossover study comparing the efficacy of 0.5% and 1.0% apraclonidine hydrochloride in 15 normal volunteers and 17 subjects with increased intraocular pressure. Apraclonidine 1% produced a maximum 30.4% +/- 14.0% (4.7 +/- 2.4 mm Hg) decrease in mean intraocular pressure in normal eyes and a 31.3% +/- 16.5% (7.6 +/- 4.2 mm Hg) decrease in eyes with increased pressure. Apraclonidine 0.5% produced a maximum 25.8% +/- 9.7% (4.0 +/- 1.7 mm Hg) decrease in mean intraocular pressure in normal eyes and a 27.4% +/- 16.0% (6.8 +/- 4.5 mm Hg) decrease in eyes with increased pressure. There was no statistically significant difference in mean percent intraocular pressure lowering effect between the 0.5% and 1.0% apraclonidine concentrations. Most subjects treated with apraclonidine had a greater than or equal to 20% reduction in intraocular pressure from baseline. Twelve hours after instillation of apraclonidine, nine of the normal volunteers had an intraocular pressure of 10 mm Hg or less. Apraclonidine produced the same percent intraocular pressure decrease regardless of the initial level of intraocular pressure.

Penetrating Keratoplasty With Trabeculectomy

Seven patients who had a mean preoperative intraocular pressure of 40 mm Hg (range, 34 to 52 mm Hg) underwent combined keratoplasty and trabeculectomy. This resulted in an average postoperative intraocular pressure of 23.7 mm Hg. Five of seven eyes had well controlled intraocular pressures throughout the postoperative period (mean follow-up, 16.1 months). This approach can achieve a satisfactory result while avoiding some of the complications of other forms of glaucoma therapy.

Primary Surgical Repair of Severe Peripheral Marginal Ectasia in Terrien's Marginal Degeneration

We have developed a safe, successful, and simple procedure for repairing the severe peripheral marginal ectasia in Terriens marginal degeneration. The area of ectasia is incised along its thinnest paralimbal dimension down to Descemets membrane. Ectatic stroma along both sides of the incision is then undermined until normal-thickness stroma is reached. After excision of excess ectatic stroma, if necessary, the normal-thickness stroma is then sutured together, primarily with 9-0 Prolene. The sutures are left in place permanently, and the remaining refractive error is corrected with spectacles or contact lenses. This technique substantially improved visual acuity in three of four patients and decreased corneal astigmatism in all four. Although one eye required resuturing, there were no complications in any case.

Herpes Simplex Virus: Recurrent and Nonrecurrent Strains

Abstract A study of three Herpes Simplex strains with different frequencies of recurrent disease was done using the New Zealand white rabbit eye model. Each of the three strains, the McKrae strain (high frequency), the E-43 strain (low frequency), and the CGA-3 (no recurrence) grew well in the rabbit corneal epithelium and produced overt recognizable disease for up to 5 days postinfection, thus minimizing differences in virus reactivation due to a lack of or insufficient ganglionic colonization. Asymptomatic shedding and spontaneous recurrences, as well as iontophoretically induced recurrences, were seen in the E-43 and McKrae strains, but not in the CGA-3-infected animals. The virus strains optimum temperature was an important aspect of its reactivation process, as shown by the failure of the nonrecurrent CGA-3 to replicate at the hosts core temperature (39°C). The fact that these explants yielded infectious virus at 33°C and not at 39°C confirmed that the CGA-3 had colonized the ganglia, and its lack of recurrences or shedding suggests a temperature-dependency relationship. Our observations were further supported by the preferential growth at 39°C of fresh clinical isolates obtained from HSV encephalitis and herpes labialis. Isolates from animals infected with the heterogeneous McKrae were classified as shedders (isolated in the absence of disease) and recurrent (isolated from a recurrent lesion). Both shedders and recurrent isolates were of a homologous nature and retained their phenotype when tested. From this study, we theorize that reactivation and disease may have different regulatory mechanisms. The type of recurrent disease (lesions, asymptomatic shedding, or none) is virus-dependent and frequency of disease may be regulated by host functions.

Piperacillin levels in human tears and aqueous humor.

Thirty patients scheduled to undergo elective intraocular surgery were each given 4 g of piperacillin intravenously. Specimens of serum, tears, and aqueous humor were collected from zero to nine hours after infusion and assayed for piperacillin content by high pressure liquid chromatography. In noninflamed eyes piperacillin sodium distributed into tears and aqueous humor in concentrations exceeding the minimum inhibitory concentration required for many gram-positive and gram-negative organisms. Higher levels of piperacillin were anticipated in patients with inflamed eyes who possessed an altered blood-aqueous barrier, and in patients receiving serial doses of this agent.

Application of adipose-derived stem cells on scleral contact lens carrier in an animal model of severe acute alkaline burn.

Purpose: To evaluate the therapeutic effect of human adipose-derived stem cells (hASCs) overlaid on a scleral contact lens (SCL) carrier in a rabbit model of ocular alkaline burn. Materials and Methods: After inducing alkaline burn in 11 New Zealand white rabbits, hASCs cultured on SCLs were placed on the right eye of 5 rabbits, SCLs without cells were used in 5, and no treatment was applied in 1 eye. Each eye was examined and photographed for corneal vascularization, opacities, and epithelial defect in week 1, 2, and 4 after surgery. After 1 month, rabbits were killed and the corneas were removed and cut in half for electron and light microscopy examination. Results: Human adipose-derived stem cells were attached to SCL surface and confluent easily. Human adipose-derived stem cells on SCL eyes showed smaller epithelial defect, less corneal opacity, corneal neovascularization relative to SCL eyes. Both groups showed no symblepharon. However, the cornea in the untreated eye was melted in 2 weeks and developed severe symblepharon. Conclusion: Human adipose-derived stem cells on SCL can reduce inflammation and corneal haziness in severe ocular alkaline burn injury in rabbits.

Azlocillin levels in human tears and aqueous humor

We administered 4 g of azlocillin sodium intravenously to 24 patients scheduled to undergo elective intraocular surgery and collected specimens of serum, tears, and aqueous humor from zero to six hours after infusion for assay by high-pressure liquid chromatography. We found that azlocillin is distributed into tears and penetrates into the aqueous humor of human volunteers with noninflamed eyes after a single intravenous dose. Levels of 4.17 micrograms/ml and 4.44 micrograms/ml were achieved in tears and aqueous humor, respectively.

Early clinical experience with a new generation Q-switched neodymium:YAG laser+++

We present early clinical results of Nd:YAG capsulotomy with a new generation Nd:YAG laser unit. We conclude that the new systems are as efficient as their early counterparts in noninvasive capsulotomy.

Penetrating keratoplasty combined with flexible anterior chamber lens implantation

We present an initial report on flexible anterior chamber lens implantation in 14 aphakic or pseudophakic bullous keratopathy patients undergoing penetrating keratoplasty. With a minimum follow-up of 12 months, the improvement in visual acuity and graft clarity is encouraging.

Techniques of flexible intraocular lens insertion during keratoplasty

Aphakic and pseudophakic corneal edema have become the primary indication for corneal transplantation. At the time of this surgery, implantation of an intraocular lens (IOL) may be considered. We describe our technique for inserting a flexible anterior chamber IOL during keratoplasty to avoid any damage to intraocular structures.