Digital imaging update.
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Analog-Digital Conversion↗
Biomedical subjects
M Abelson
Publications and source records attributed to M Abelson.
Comparison of the topical ocular antiallergic efficacy of emedastine 0.05% ophthalmic solution to ketorolac 0.5% ophthalmic solution in a clinical model of allergic conjunctivitis.
PURPOSE: To compare the clinical efficacy of emedastine ophthalmic solution to that of ketorolac ophthalmic solution using a conjunctival allergen challenge model. METHODS: The conjunctival allergen challenge model was used in this randomized, double-masked, single center, crossover study. The titer of allergen that elicited a positive allergic reaction was selected. After at least 14 days, 36 subjects were randomized into two groups of 18 to receive either emedastine in one eye and placebo in the contralateral eye, or ketorolac in one eye and placebo in the contralateral eye. Ten minutes after drug instillation, subjects were challenged with antigen. At 3, 10 and 20 minutes following challenge subjects graded ocular itching and were assessed for hyperemia in conjunctival, ciliary, and episcleral vessel beds. Approximately 14 days later, subjects received the alternate treatment in one eye and placebo in the contralateral eye. They were again challenged with allergen and their responses were rated in the same manner. Ocular discomfort was assessed by the subjects after administration of each study drug. RESULTS: Emedastine significantly (p < 0.05) inhibited ocular itching and redness in vascular beds following topical ocular administration. In contrast, ketorolac failed to significantly inhibit ocular itching or redness in this study. Patient assessment of comfort indicated emedastine was significantly (p < 0.05) more comfortable than ketorolac upon topical ocular administration. CONCLUSION: Emedastine is superior to ketorolac in controlling itching and redness, the cardinal symptom and sign of allergic conjunctivitis.
Anti-Inflammatory Agents, Non-Steroidal↗
Comparative evaluation of olopatadine ophthalmic solution (0.1%) versus ketorolac ophthalmic solution (0.5%) using the provocative antigen challenge model.
OBJECTIVE: This study was conducted to compare the efficacy and safety of olopatadine ophthalmic solution (0.1%) with ketorolac ophthalmic solution (0.5%) in a clinical model of acute allergic conjunctivitis. Olopatadine is a dual acting H1 histamine receptor antagonist and a mast cell stabilizer, shown to be effective in treating allergic conjunctivitis. Ketorolac is a non-steroidal anti-inflammatory drug approved in the United States for the relief of ocular itching associated with seasonal allergic conjunctivitis. METHODS: The provocative antigen challenge model was used in this randomized, double-blind, single-center, crossover study. The allergen and concentration that consistently elicited a positive allergic reaction was used for challenge. After at least 14 days, subjects were randomized to receive either olopatadine in one eye and placebo in the contralateral eye, or ketorolac in one eye and placebo in the contralateral eye. Twenty-seven minutes after drug instillation subjects were challenged with allergen. At 3, 10, and 20 minutes following allergen challenge, subjects graded ocular itching and were assessed for hyperemia in conjunctival, ciliary, and episcleral vessel beds. Approximately 14 days later, subjects received the alternate treatment in one eye and placebo in the contralateral eye. They were again challenged with allergen and their responses were rated in the same manner. RESULTS: Olopatadine significantly (p < 0.0001) reduced both ocular itching and hyperemia in all three vessel beds compared to placebo at all time points tested following allergen challenge. Ketorolac did not significantly reduce itching and showed a trend of increased hyperemia compared to placebo. Olopatadine was significantly (p < 0.001) more effective than ketorolac in reducing hyperemia and ocular itching at all time points and was also significantly (p < 0.05) more comfortable than ketorolac as reported by subjects immediately following drug instillation. CONCLUSION: The study demonstrated that olopatadine is effective and safe in preventing and treating ocular itching and hyperemia associated with acute allergic conjunctivitis and is more effective and more comfortable than ketorolac.
Acute Disease↗
Efficacy of hyaluronidase in reducing increases in intraocular pressure related to the use of viscoelastic substances.
OBJECTIVE: To evaluate the efficacy of hyaluronidase in preventing increases in intraocular pressure related to injections of hyaluronan-containing viscoelastic substances. METHODS: Twenty-five white rabbits were divided into 5 groups. In groups 1 through 4, 0.15 mL of aqueous humor was removed and replaced with 0.10 mL of a viscoelastic substance in both eyes. Additionally, 10 units of hyaluronidase (0.05 mL) was injected in the anterior chamber of the right eye, whereas the left eye was injected with a volumetrically equivalent dose of balanced saline solution. Viscoelastic substances tested were Healon and Healon GV (Pharmacia & Upjohn, Kalamazoo, Mich), Viscoat (Alcon Laboratories, Fort Worth, Tex), and Ocucoat (Storz Ophthalmics, Clearwater, Fla). In group 5, right eyes were injected with 10 units of hyaluronidase and the left eyes were treated with balanced saline solution. RESULTS: After injections of viscoelastic substance, intraocular pressure rose rapidly, reaching a peak at approximately 46 hours after injection and returning to preinjection levels within 24 hours. Hyaluronidase significantly decreased intraocular pressure when used with Healon, Healon GV, and Viscoat, but not with Ocucoat. When injected in the absence of viscoelastic, hyaluronidase appeared to decrease intraocular pressure, but this result was not statistically significant. CONCLUSIONS: Injections of hyaluronidase into the anterior chamber of rabbits effectively prevent increases in intraocular pressure induced by hyaluronan-containing viscoelastic substances. This effect may be related to the ability of hyaluronidase to cleave hyaluronan moieties.
Animals↗
Effectiveness of BION tears, Cellufresh, Aquasite, and Refresh Plus for moderate to severe dry eye.
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Adult↗
The conjunctival provocation test model of ocular allergy: utility for assessment of an ocular corticosteroid, loteprednol etabonate.
Two studies were conducted using the conjunctival provocation test (CPT) model of ocular allergy. The objective of the first study was to evaluate the sensitivity of the CPT model to a topical corticosteroid. Selected was loteprednol etabonate 0.5%, previously found effective in the treatment of ocular allergy and inflammation. The study was a randomized double-masked, placebo-controlled, paired-comparison of loteprednol etabonate 0.5% (LE), b.i.d. or q.i.d. Sixty subjects who had a minimum pre-determined allergic response received LE in one eye and placebo in the fellow eye for 28 days from Day 7 to Day 35. Antigen challenges were carried out on Days 0, 7 (baseline), 21 and 35. The primary endpoints were interocular differences in itching and mean redness (the average of ciliary, conjunctival and episcleral vessel beds). LE (either b.i.d. or q.i.d.) was significantly more effective than placebo for reducing mean redness and itching. No clinical or statistically significant changes in intraocular pressure were observed. Based upon the results of Study 1, we used the CPT model to aid in the selection of a concentration of loteprednol etabonate for subsequent studies in environmental seasonal allergic conjunctivitis. This was a randomized double-masked, placebo-controlled, paired-comparison of loteprednol etabonate 0.1%, 0.2% and 0.3%, q.i.d. in 88 subjects. The dosing and testing regimen was similar to the first portion of the study. Loteprednol etabonate, 0.1%, 0.2% and 0.3%, was numerically superior to the placebo in reducing mean redness and itching. At the 20-minute post allergen challenge, the 0.1% concentration was significantly superior (p < 0.05) to the placebo on Visit 4 (2 and 4 hour challenge) in reducing the mean redness; however, LE was only numerically superior in relieving itching. The 0.2% concentration was significantly superior (p < 0.05) to the placebo in the reduction of mean redness and itching on Visit 3 (Day 21) and in reduction of mean redness on Visit 4 (4 hour challenge). The 0.3% concentration was significantly superior (p < 0.05) to the placebo in the reduction of mean redness on all visits, and statistically significant in the reduction of itching on Visit 4 (4 hour challenge). While there were some elevations of IOP with LE 0.2%, they were not clinically significant. In conclusion, the CPT model of ocular allergy is useful in the evaluation of corticosteroids. Furthermore, based upon a dose-response study in this model, 0.2% loteprednol etabonate was selected for further evaluation in environmental seasonal allergic conjunctivitis studies.
Adult↗
Understanding recent PC technology developments.
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Computers↗
Effects of flurbiprofen and indomethacin on acute cystoid macular edema after cataract surgery: functional vision and contrast sensitivity.
We examined the effect of acute cystoid macular edema (CME) on contrast sensitivity. Eyedrops were instilled into the surgically treated eye f1p4 times daily for two days preoperatively and for three months postoperatively. Angiographic and clinical CME were measured, as were contrast sensitivity and Snellen acuity. Jaeger visual acuity equivalents were calculated and digital imaging techniques used to simulate visual function. We found that angiographic CME reduces functional vision as measured by contrast sensitivity and visual acuity over a large range of sizes. In patients treated with the flurbiprofen vehicle, those without CME had higher mean contrast sensitivity scores than those with CME; this increased over time. Those treated with flurbiprofen and indomethacin had slightly higher contrast sensitivity scores than vehicle-treated patients; this also increased over time, most notably in the higher spatial frequencies. Flurbiprofen treatment improved contrast sensitivity in patients with and without CME significantly at 12 cycles per degree. Flurbiprofen-treated patients with CME in general had higher contrast sensitivity scores than vehicle-treated patients. In this population of patients having cataract surgery, treatment with flurbiprofen or indomethacin reduced the loss of functional vision associated with CME.
Acute Disease↗
An open letter to the readers of Ortho Bytes.
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Humans↗
Complications and symptoms in disposable extended wear lenses compared with conventional soft daily wear and soft extended wear lenses.
We conducted a historical cohort study of 2,433 cosmetic contact lens wearers (1,055 conventional [non-disposable] daily wear lens users, 905 disposable extended wear lens users, and 473 conventional extended wear lens users) in order to estimate the rates of occurrence of complications and symptoms among disposable extended wear contact lens users and compare these rates with those for conventional soft daily wear users and conventional soft extended wear users. Data were abstracted from the office records of eight eye care practitioners for the period February 1987 through April 1989. The prevalence of all complications for disposable extended wear lens users was not significantly different from the prevalence for conventional daily wear lens users but was significantly lower than the prevalence for conventional extended wear lens users. The incidence of ulcers among disposable extended wear lens users did not differ significantly from the incidence found with conventional extended wear, but was significantly higher than the rate for conventional daily wear. Disposable extended wear lenses, in contrast to conventional extended wear lenses, may be more strongly associated with benign peripheral infiltrates than with the more serious central ulcers. Disposable extended wear lens users reported symptoms less frequently at routine scheduled visits than both conventional daily wear and conventional extended wear users and had a lower rate of unscheduled visits for complications and symptoms.
Adult↗
Biochemical and behavioral characterization of a novel cholinergic agonist, SR 95639.
Selective M1 cholinergic agonists may be useful in treating dementias due to cholinergic hypofunction. SR 95639 has recently been described as such a compound. We found the compound to have affinity for M1 sites (Ki = 2.1 microM) which was approximately 3-fold higher than its affinity for M2 sites. Functional partial agonism was suggested by an inconsistent increase in phosphoinositide (PI) turnover in rat hippocampal slices, combined with blockade of carbachol-stimulated PI turnover. In vivo M2-mediated effects were absent. Scopolamine-induced hyperactivity was attenuated by SR 95639 and scopolamine-impaired inhibitory avoidance and radial maze performance were improved. The compound appears to be a weakly selective M1 partial agonist with potential advantages over existing compounds.
Animals↗
Correlation between C-reactive protein and throat culture results in patients with pharyngitis.
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Adolescent↗
Principles and microscopic confirmation of surface quality of two new waterjet-based microkeratomes.
PURPOSE: The HydroBlade and the HydroBrush keratomes are waterjet-based devices for corneal surgery that operate at normal intraocular pressure in two different modes: removal of parallel or shaped lenticules or hinged flaps with a small diameter, high speed waterjet; and removal of the epithelium with a waterjet sheet. The operating principles as well as histology of the cut surfaces are described. METHODS: A flap was made in one cadaver eye with a Chiron ACS keratome and in the second eye with the HydroBlade keratome. The epithelium was removed in one cadaver eye with a surgical blade and in the second eye by the HydroBrush keratome. Scanning and transmission electron microscopy and light microscopy was obtained. RESULTS: The HydroBlade keratome cleaved only cross-linking fibrils and left intact keratocytes. Shape and dimensions of the flap were accurate. There was no observable hydration or significant heating of the tissue. Mechanical forces on the cornea were small. The HydroBrush keratome removed the epithelium quickly, left no epithelial debris, and did not damage Bowman's layer. CONCLUSION: With the HydroBlade keratome, the cuts are ideal blunt dissections. Epithelial removal with the HydroBrush keratome is effective and quick.
Cornea↗
Hydroepithelial keratectomy in rabbits with a waterjet-based instrument.
BACKGROUND: Corneal epithelial removal finds multiple applications in ophthalmic surgery (epithelial herpes infections, recurrent epithelial erosion, corneal ulcers and plaques, and intraoperative epithelial clouding). Photorefractive keratectomy is initiated by removal of the epithelium. Current techniques for epithelial removal are suboptimal. We studied the safety and effectiveness of a new technique, hydroepithelial keratectomy, performed with the HydroBrush keratome on live rabbits. METHODS: Eighteen rabbits (18 eyes) underwent hydroepithelial keratectomy and 18 rabbits (18 eyes) underwent epithelial removal with a surgical blade (blade group). Twelve rabbits were euthanized immediately after the procedure. Twenty-four rabbits were followed for up to 120 hours after treatment. Ultrastructural analysis was performed with light and electron microscopy. RESULTS: The hydroepithelial keratectomy group healed a mean 53 hours after treatment; the blade group healed a mean 78 hours after treatment. The HydroBrush keratome exposed the basement membrane and the basal cell membrane of the epithelium. The blade exposed patches of basement membrane, as well as stroma and cell debris. CONCLUSIONS: Hydroepithelial keratectomy with the HydroBrush keratome is effective and safe. Wound healing after hydroepithelial keratectomy is faster than after blade removal. Unlike the blade, the HydroBrush keratome exposed a smooth surface, devoid of debris, with well-defined edges and round shape without hydration nor dehydration of the tissue.
Animals↗