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Biomedical subjects

R W Yee

Publications and source records attributed to R W Yee.

At least 19 recordsLinked to original sources
PubMed1999

Lyme disease associated with unilateral interstitial keratitis.

PURPOSE: To report a case of Lyme disease that presented with a single nummular unilateral interstitial keratitis. METHODS: Case report and review of the literature. RESULTS: A 57-year-old black man who had contact with freshly killed deer had a chief complaint of foreign-body sensation in his right eye (OD) that had been diagnosed and treated for herpes simplex stromal keratitis. The patient underwent a systemic workup for interstitial keratitis. All results including RPR and MHA-TP were negative except for Lyme antibody titer (enzyme-linked immunosorbent assay [ELISA]) 178 U/ml (normal, <159 U/ml). CONCLUSION: Interstitial keratitis from Lyme disease has been regarded as a bilateral disease in the literature. We present this infrequent ocular manifestation of Lyme disease as a rare single nummular unilateral presentation.

Anti-Bacterial Agents↗
PubMed1998

Lasso procedure to revise overcorrection with radial keratotomy.

PURPOSE: To report three patients who underwent the lasso procedure to revise overcorrection with radial keratotomy. METHODS: Case report and review of the literature. RESULTS: Four eyes of three patients who had undergone radial keratotomy with resultant hyperopic overcorrection underwent a lasso procedure. Before the procedure, average cycloplegic refraction spherical equivalent was +3.656 +/- 1.352 diopters, and average manifest refraction spherical equivalent was +2.250 +/- 0.621 diopters. A 10.0 monofilament nylon suture was placed in a circumferencial manner through the corneal stroma and overlapping the old radial keratotomy incisions. At 1 month postoperatively, best-corrected visual acuity was 20/20 in all four eyes, with average cycloplegic refraction spherical equivalent +0.438 +/- 1.423 diopters and average manifest refraction spherical equivalent -0.156 +/- 1.147 diopters. Mean delta cycloplegic refraction spherical equivalent was 3.219 +/- 1.724. CONCLUSIONS: The lasso procedure provides an immediate solution for symptomatic overcorrected hyperopic eyes after radial keratotomy. Predictability and long-term stability necessitate further follow-up.

Adult↗
PubMed1998

Analgesic efficacy and safety of nonpreserved ketorolac tromethamine ophthalmic solution following radial keratotomy. Ketorolac Radial Keratotomy Study Group.

PURPOSE: To compare the analgesic efficacy and safety of nonpreserved ketorolac tromethamine 0.5% with those of its vehicle in the treatment of postsurgical ocular pain following radial keratotomy. METHODS: This study employed a multicenter, double-masked, randomized, parallel-group design. Radial keratotomy patients were treated with either nonpreserved ketorolac tromethamine 0.5% or its vehicle four times daily for up to 3 days following surgery. Patients were provided with an escape medication (acetaminophen) for use only as needed for intolerable pain. RESULTS: Patients treated with ketorolac reported significantly greater pain relief (P < or =.023), less pain intensity (P < or =.047), less use of escape medication (P < or =.001), fewer symptoms of ocular discomfort (P=.024), and fewer sleep disturbances (P < or =.013) than did patients treated with vehicle. No treatment-related adverse events were reported in the ketorolac group, and only one treatment-related adverse event was reported in the vehicle group. Most other safety findings were equivalent in the two treatment groups except that there were significantly less eyelid erythema (P=.026) and eyelid edema (P < or =.001) in the ketorolac group. CONCLUSIONS: Nonpreserved ketorolac tromethamine 0.5% ophthalmic solution was significantly more effective than, and as safe as, vehicle in the treatment of postoperative pain associated with radial keratotomy. Therefore, topical ketorolac may be a valuable treatment option for the maintenance of patient comfort following refractive surgery.

Adult↗
PubMed1997

Linkage mapping of Thiel-Behnke corneal dystrophy (CDB2) to chromosome 10q23-q24.

Corneal dystrophy of the anterior basement membrane is a heterogeneous set of diseases characterized by painful, recurrent, bilateral erosions of the cornea, which often result in significant visual impairment. There are several similar but clinically distinct forms of anterior basement membrane/Bowman's membrane disease, including two autosomal dominant forms, Reis-Bücklers and Thiel-Behnke corneal dystrophy. Genes causing autosomal, nonsyndromic corneal dystrophy have been mapped to human chromosomes 1p, 5q, 12q, 16q, 17p, and 20p. Using microsatellite markers closely linked to the known corneal dystrophy loci, we excluded linkage between the known sites and the disease locus in a large, four-generation family with Thiel-Behnke corneal dystrophy. A genome-wide search using a panel of microsatellite markers demonstrated a maximum two-point lod score of 4.0 at 0% recombination between the disease locus in this family and the marker D10S1239, which maps to 10q23-q24. Testing with additional microsatellite markers from 10q places the disease locus between D10S677 and D10S1671, a distance of approximately 12.0 cM, with a maximum multipoint lod score of 5.5. Based on this evidence, we have identified another locus (CDB2) for corneal dystrophy of the anterior basement membrane/Bowman's membrane, Thiel-Behnke type, further demonstrating the exceptional genetic and phenotypic heterogeneity of these diseases.

Chromosome Mapping↗
PubMed1997

Ocular integrity after refractive procedures.

PURPOSE: The purpose of the study was to determine the integrity of human eyes after refractive procedures. METHODS: Whole human globes underwent either radial keratotomy (RK) with eight incisions, automated lamellar keratoplasty (ALK), photorefractive keratectomy (PRK), or excimer laser assisted in situ keratomileusis (LASIK). Eyes then were subjected to quantitatively increasing levels of trauma until rupture occurred. RESULTS: All eyes operated on required less energy to rupture as compared with that of control eyes. The mean number of trials required for rupture is as follows (energy doubled with each successive trial): normal, 4.29; LASIK, 3.80; ALK, 3.67; PRK, 3.60; and RK, 2.83. The level of energy required to rupture normal, ALK, PRK, and LASIK eyes was not significantly different. All RK eyes ruptured at incisions. Most ALK, PRK, and LASIK eyes ruptured near the flap edge or limbus. Most normal eyes ruptured with both corneal and scleral involvement. Age of tissue donors at the time of death and time elapsed between death and procedure were not significantly different between groups (P = 0.88 and 0.79, respectively). CONCLUSIONS: The energy required to rupture ALK, PRK, and LASIK eyes is not significantly different from that for normal eyes. The RK eyes ruptured with significantly less energy than did normal eyes. All RK eyes ruptured at incision sites.

Adult↗
PubMed1997

Intraoperative mitomycin in primary pterygium excision. A prospective, randomized trial.

PURPOSE: Conjunctival autograft transplantation and postoperative mitomycin therapy are two adjuvant treatment methods shown to lessen the high pterygium recurrence rate seen with simple excision alone. The authors conducted a prospective, randomized study comparing these two techniques with a relatively new treatment method using intraoperative mitomycin application. METHODS: Fifty patients with 56 primary pterygia were randomized to 1 of 3 treatment groups: conjunctival autograft (group 1), postoperative mitomycin 0.2 mg/ml four times a day x 7 days (group 2), and intraoperative mitomycin 0.4 mg/ml x 3 minutes (group 3). The mean follow-up time was 16 months (range, 6 to 28 months). RESULTS: Recurrences developed in 4 (22.2%) of 18 eyes in group 1, 4 (21.1%) of 19 eyes in group 2, and 2 (10.5%) of 19 eyes in group 3. Complications developed in two, patients from group 2, scleral thinning managed successfully with a scleral patch graft, and epithelial toxicity that resolved on discontinuation of mitomycin on postoperative day 6. There were no complications in the other two groups. CONCLUSIONS: Intraoperative mitomycin is a simple and effective alternative to postoperative mitomycin therapy, showing the lowest recurrence rate in their series with no toxicity during the study period. If the decision is made to use adjunctive mitomycin, the authors recommend intraoperative application over postoperative administration.

Administration, Topical↗
PubMed1997

Ocular penetration and pharmacokinetics of topical fluconazole.

The high bioavailability and low toxicity of fluconazole, a stable, water-soluble, low-molecular-weight bis-triazole antifungal, makes it a good candidate for consideration as a topical ocular agent. The penetration of fluconazole (0.2%) into the corneas and aqueous humors of New Zealand white rabbits was assayed by gas liquid chromatography (GLC). Peak corneal levels occurred essentially immediately at 5 min in the corneas [debrided, 8.2 +/- 1.2 micrograms/g; nondebrided, 1.6 +/- 0.6 microgram/g; (mean +/- SEM)] and at 15 min after application in the aqueous [debrided, 9.4 +/- 2.3 micrograms/ml; nondebrided, 1.6 +/- 0.6 microgram/ml; (mean +/- SEM)]. Estimating from semilogarithmic plots of the data, the halflife (t1/2) in the debrided eyes was 15 min; in the nondebrided eyes, t1/2 was 30 min. A loading dose of a 20-microliter drop per min for 5 min yielded levels of 59.9 +/- 11.3 micrograms/g (mean +/- SEM) in the debrided corneas and 32.4 +/- 1.9 micrograms/ ml (mean +/- SEM) in the corresponding aqueous humor. A regimen consisting of this loading dose followed by one 20 microliters drop/h for 6 h showed 45.9 +/- 3.5 micrograms/g (mean +/- SEM) in the debrided corneas and 8.8 +/- 1.7 micrograms/ml (mean +/- SEM) in the corresponding aqueous. The same regimen yielded values of 3.1 +/- 0.2 micrograms/g in the nondebrided corneas and 1.3 +/- 0.2 micrograms/ml (mean +/- SEM) in the aqueous. Minimal inhibitory concentrations (MIC) at 24 h for yeasts ranged from < 1.25 to 20 micrograms/ml, for hyaline molds from 2.5 to > 20 micrograms/ml, and dematiaceous molds from < 1.25 to > 20 micrograms/ml. Topical fluconazole exhibits pharmacokinetics and selective MICs that merit further evaluation for its ophthalmic use as a topical antifungal agent.

Administration, Topical↗
PubMed1996

Microscopic polyangiitis with ocular involvement.

Microscopic polyangiitis is an exclusively small-vessel (arterioles, capillaries, or venules) vasculitis that primarily involves the kidney and often involves the lungs, skin, or nervous system. Characteristic features include focal segmental glomerulonephritis, nongranulomatous necrotizing vasculitis, and serum positive for perinuclear-staining antineutrophil cytoplasmic antibodies (P-ANCA). We report a case of microscopic polyangiitis with previously unreported eyelid and conjunctival manifestations that responded well to immunosuppressive therapy.

Adult↗
PubMed1996

Effects of acetylcholine and carbachol on bovine corneal endothelial cells in vitro.

PURPOSE: To assess the relative cytotoxicity of Miochol (1% acetylcholine and mannitol), Miostat (0.01% carbachol, sodium, potassium, magnesium, and calcium salts), and their individual components using in vitro models of bovine corneal endothelial cells (BCECs). SETTING: Laboratories of the Departments of Ophthalmology and Physiology, The University of Texas Health Science Center, Houston. METHODS: The study was divided into four experiments. Experiment 1 used a confluent model to compare the relative cytotoxicity of Miochol and Miostat on BCECs following short-term exposure. In Experiments 2, 3, and 4, the proliferation model (preconfluent BCECs) was used to detect the possible cytotoxicity of individual components in the commercial preparations of the miotics; i.e., the preconfluent BCECs were exposed to buffered salt solutions containing mannitol (1%, 3%, and 4%), acetylcholine (0.5%, 1%, and 2%), or carbachol (0.1%, 0.5%, and 1%) for 3 hours. RESULTS: Confluent BCECs exposed to Miochol for 30 minutes underwent necrosis and degeneration, while those treated with Miostat did not show any morphological changes. None of the tested solutions except 2% acetylcholine and 1% carbachol caused observable changes in the nuclear densities of BCECs at 24, 72, 120, and 168 hours. CONCLUSION: The major components of Miochol (acetylcholine and mannitol) were found to be nontoxic; the cytotoxicity of the preparation was possibly due to the lack of an appropriate balanced salt solution. These findings may influence the selection of a miotic for use during intraocular surgery.

Acetylcholine↗
PubMed1995

Low-dose intraocular tissue plasminogen activator treatment for traumatic total hyphema, postcataract, and penetrating keratoplasty fibrinous membranes.

Tissue plasminogen activator (tPA) has been used to treat severe postcataract and vitrectomy fibrinous membranes, but intraocular bleeding has occurred with doses of 25 micrograms or higher. We report three patients, one with nonclearing total hyphema and uncontrollable intraocular pressure and two with severe fibrinous membrane formation, who had treatment with low-dose (4 micrograms to 6 micrograms) intraocular tPA. Although the fibrinous membranes or hyphema resolved in all three patients, they recurred and bleeding that required additional treatment occurred in one patient. Intraocular low-dose tPA may minimize the risk of corneal and retinal toxicity and may be considered an alternative treatment in intractable cases. However, secondary intraocular hemorrhage can occur, and the timing between the initial vascular injury, treatment with tPA, and subsequent bleeding may reduce the risk of further hemorrhaging.

Adult↗
PubMed1995

Standardization of conjunctival impression cytology.

Lack of standardization limits the potential of conjunctival impression cytology as a clinical and research tool. This may be attributed to the variety of filter paper currently used. MF Millipore membrane filters of pore sizes 8.0, 3.0, 0.45, 0.22, and 0.025 micron were tested. Samples obtained from 30 eyes of rabbits were randomized and scored by four masked observers for cellularity and morphologic preservation. Cellularity was significantly greater with pore sizes 8.0, 3.0, and 0.45 micron versus 0.22 and 0.025 micron (p < or = 0.001), with an 83% correlation among four scorers. In contrast, morphology was better preserved in the smaller pore size papers (0.22 and 0.025 micron) when compared with larger pore sizes (p = 0.048). Using the best two filter papers (0.22 and 0.025 micron) and an ophthalmodynamometer, either 40, 60, or 80 g of pressure was applied for 3 s to each pore size paper to see whether cellularity could be increased. Cellularity was greater with pore size 0.22 than 0.025 micron (42.3 +/- 19.8 versus 8.7 +/- 6.4). Regardless of the pore size of the filter paper, cellularity was significantly improved at 60 g when compared with either 80 or 40 g. The results show that to maximize cell acquisition, a paper with medium pore size (0.22 micron) and a pressure of 60 g may be the best choice.

Animals↗
PubMed1993

Healon GV in extracapsular cataract extraction with intraocular lens implantation.

A randomized masked study was performed to compare Healon GV, a new higher molecular weight sodium hyaluronate viscoelastic, with Healon in extracapsular cataract surgery with posterior chamber intraocular lens insertion. Seventy patients were randomly divided into two groups. Postoperative intraocular pressures, pachymetry, endothelial cell counts and morphology, amount of viscoelastic and irrigating solution used, difficulty of surgery, and postoperative flare and cells were measured. Postoperative pressures were not significantly different between the Healon and Healon GV treatment groups, except at the eight-hour observation period, when the pressure was higher in the Healon GV group (P = .02). There was a significant (P = .002) reduction in the amount of viscoelastic required in the Healon GV group. Cell counts and morphology were not significantly different between the groups. Other parameters showed no significant difference. Clinically, Healon GV handled like Healon during instillation into the anterior chamber and aspiration at the end of the case. It did, however, appear to be much more effective at maintaining the anterior chamber, as demonstrated in the smaller amount of viscoelastic required.

Aged↗
PubMed1992

Use of in vitro models of bovine corneal endothelial cells to determine the relative toxicity of viscoelastic agents.

Healon, Viscoat and Amvisc Plus (Amvisc+) are commercial preparations containing hyaluronic acids of different molecular weights and viscosities. Cytotoxicity of these preparations to the corneal endothelium may be a factor in postsurgical recovery of the cornea. Using different in vitro models of bovine corneal endothelial cells (BCEC), three experiments to compare the possible detrimental effects of these viscoelastic agents were designed. In the confluent model, confluent BCEC were exposed to viscoelastic agents and the control to Balanced Salt Solution Plus (BSS+) for one hour and the nuclear density (nuclei/mm2) was assessed at 24 and 168 hours. At both times, the BCEC exposed to Healon showed the highest nuclear densities. In the preconfluent model, BCEC were treated for one hour at 48 hours post-seeding. The nuclear density of the BCEC was assessed at 24 hours. The BCEC exposed to Healon showed the highest density, followed by those exposed to Amvisc+ and then Viscoat. In the proliferation model, BCEC were cultured in media containing 1%, 5%, and 10% viscoelastic agents. The growth curves based on nuclear densities at 0, 24, 72, 120, and 168 hours in all treatment groups did not differ significantly from the control. The results indicate that the undiluted Healon was significantly less toxic in the preconfluent and confluent BCEC models.

Analysis of Variance↗
PubMed1992

Effects of flurbiprofen and suprofen on the miotic activity of 1% acetylcholine and 0.01% carbachol.

The nonsteroidal antiinflammatory agents (NSAIAs) flurbiprofen and suprofen applied topically to reduce miosis may counteract the desired effects of miotics used during ocular surgery. In a pigmented rabbit model, 1% acetylcholine was shown to cause a greater, significant initial (for the first 30 minutes) constriction (P less than .05) than 0.01% carbachol in eyes pretreated with flurbiprofen and suprofen. From 2 to 8 hours, NSAIA pretreatment had a greater miotic effect with carbachol than with acetylcholine. There were no significant differences between flurbiprofen and suprofen on the miotic effect of carbachol or acetylcholine.

Acetylcholine↗
PubMed1991

Resolution of microsporidial epithelial keratopathy in a patient with AIDS.

A patient with a positive human immunodeficiency virus (HIV) titer and cryptococcal meningitis suffered bilateral epithelial keratopathy caused by Encephalitozoon, which did not respond to sulfas, erythromycin, bacitracin, tobramycin, neomycin, polymyxin B, or fluconazole. Eventual administration of itraconazole for the meningitis apparently produced resolution of the long-lasting (2-month) ocular infection. This new oral triazole antifungal may be valuable against the increasingly prevalent microsporidial infections in patients with acquired immune deficiency syndrome. Debulking of the infection by corneal scraping may have contributed to the authors' success.

Acquired Immunodeficiency Syndrome↗