Silicone oil tamponade to seal macular holes.
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Humans↗
Biomedical subjects
S W Siegner
Publications and source records attributed to S W Siegner.
Effect of calcium channel blockers alone and in combination with antiglaucoma medications on intraocular pressure in the primate eye.
PURPOSE: To determine the effect of representative members from six classes of calcium channel blockers on intraocular pressure in the primate eye. Other antiglaucoma medications were administered with verapamil to determine their combined effect on intraocular pressure. METHODS: Six healthy cynomolgus monkeys were anesthetized, and baseline intraocular pressure was measured. Drug-containing solution (50 microL) was instilled in one eye and intraocular pressure was measured in both eyes 90 minutes later. RESULTS: All classes of calcium channel blockers significantly lowered intraocular pressure in the treated eye. The percent reduction in intraocular pressure compared with the baseline pressure was 10% for verapamil (P < 0.002), 18% for nifedipine (P < 0.001), 15% for diltiazem (P < 0.001), 17% for flunarizine (P < 0.001), 19% for prenylamine (P < 0.001), and 6% for perhexiline (P < 0.01). In the fellow eye, a significant reduction in intraocular pressure was also seen with all calcium channel blockers except perhexiline, which suggested a crossover effect. In contrast, neither vehicle treated nor contralateral eyes showed a lowering of intraocular pressure when tested under the same conditions. In the treated eye, 0.5% timolol (P < 0.01) and 0.05% clonidine (P < 0.02) combined with 0.25% verapamil each appeared to produce an additive effect, with a significantly greater pressure-lowering effect than either agent alone. In addition, 0.005% pilocarpine (P < 0.001) and 0.00125% demecarium (P < 0.01) combined with 0.25% verapamil each appeared to produce a synergistic effect, with a significantly greater reduction in intraocular pressure than both agents combined. CONCLUSIONS: Topical calcium channel blockers and combinations of verapamil with antiglaucoma medications may provide a useful alternative for reducing intraocular pressure in patients with ocular hypertension or primary open-angle glaucoma.
Animals↗
Intermediate-term clinical experience with the Ahmed Glaucoma Valve implant.
PURPOSE: We studied the intermediate-term clinical experience with the Ahmed Glaucoma Valve implant (New World Medical, Inc, Rancho Cucamonga, California). METHODS: In this multicenter, retrospective case series, we studied 159 eyes (144 patients) treated with the Ahmed Glaucoma Valve with a mean +/- SEM (standard error of mean) follow-up of 13.4 +/- 0.7 months (range, 4 to 44 months). The mean +/- SEM age was 60.9 +/- 1.9 years (range, 0.1 to 103 years). Surgical success was defined as intraocular pressure less than 22 mm Hg and greater than 5 mm Hg without additional glaucoma surgery and without loss of light perception. Postoperative use of antiglaucoma medications was not a criterion for success or failure. The definition of hypotony was intraocular pressure of 5 mm Hg or less in two consecutive visits. RESULTS: Intraocular pressure was reduced from a mean of 32.7 +/- 0.8 mm Hg before surgery to 15.9 +/- 0.6 mm Hg (P < .0001) at the most recent follow-up after surgery. The number of antiglaucoma medications was decreased from 2.7 +/- 0.1 before surgery to 1.1 +/- 0.1 after surgery (P < .0001). The cumulative probability of success was 87% at 1 year and 75% at 2 years after surgery (Kaplan-Meier life-table analysis). Postoperatively, 24 (15%) of 159 eyes had intraocular pressure greater than or equal to 22 mm Hg. The visual acuity was improved or within one Snellen line in 131 eyes (82%). Complications occurred in 75 eyes (47%), the majority of which did not affect surgical outcome. The most common complication was obstruction of the tube, which was observed in 17 eyes (11%). Transient postoperative hypotony was found in 13 eyes (8%). CONCLUSIONS: The Ahmed Glaucoma Valve implant is effective in lowering intraocular pressure, and postoperative hypotony is not commonly associated with this implant.
Adolescent↗
Distribution of verapamil and norverapamil in the eye and systemic circulation after topical administration of verapamil in rabbits.
Our purpose was to determine the pharmacokinetics of verapamil and its active metabolite norverapamil after topical administration of verapamil in rabbits. New Zealand white albino rabbits were given 50 microl of verapamil ophthalmic formulation topically in each eye. Samples obtained at various time points were analyzed with high performance liquid chromatography and tandem mass spectrometry. The elimination half-life of verapamil after treatment with 0.5% verapamil was 0.76 hour for aqueous, 4.34 hours for vitreous, and 1.82 hours for serum. The peak concentrations for aqueous, vitreous, and serum were 2.34 x 10(-6) M by 0.5 hour, 1.57 x 10(-7) M at 2 hours, and 3.39 x 10(-8) M by 0.5 hour following instillation of one drop of 0.5% verapamil; and 1.41 x 10(-6) M by 0.5 hour, 5.48 x 10(-8) M at 4 hours, and 1.20 x 10(-8) M by 0.5 hour following 0.25% verapamil, respectively. The metabolite norverapamil was found at peak concentrations of 8.65 x 10-(8) M by 0.5 hour in aqueous, 1.65 x 10(-8) M at 2 hours in vitreous, and 1.30 x 10(-9) M by 0.5 hr in serum following administration of 0.5% verapamil. The elimination half-life of norverapamil for aqueous, vitreous, and serum following treatment with 0.5% verapamil was 0.91 hour, 1.43 hours, and 3.60 hours, respectively. We conclude that topical verapamil, administered to the rabbit eye, is rapidly absorbed in the aqueous, vitreous, and blood. Norverapamil, which is an active metabolite of verapamil, can be detected in the aqueous and vitreous of the rabbit eye after topical administration, suggesting enzymatic degradation of verapamil within the eye.
Administration, Topical↗
Color Doppler ultrasound measurements after topical and retrobulbar epinephrine in primate eyes.
PURPOSE: To determine the effects of topical epinephrine and retrobulbar anesthesia containing lidocaine with epinephrine on retrobulbar hemodynamic measurements in the primate eye, using color Doppler ultrasound. METHODS: Color Doppler ultrasound measurements were performed at baseline and 90 minutes after masked administration of topical 2% epinephrine or balanced salt solution to six cynomolgus monkeys. Measurements were also performed at baseline and 30 minutes after retrobulbar injection of 2% lidocaine, with or without 1:200,000 epinephrine. RESULTS: After topical epinephrine, color Doppler ultrasound measurements were not significantly different compared with baseline measurements in the central retinal artery, posterior ciliary arteries, and superior ophthalmic vein. There were decreased systolic and diastolic velocities in the ophthalmic artery (P < 0.03 and P < 0.02, respectively) after topical epinephrine; however, Pourcelot's ratio (resistive index) was not significantly different compared with that at baseline. In contrast, there were marked changes in the retrobulbar arterial circulation after retrobulbar injection of lidocaine with epinephrine. The systolic and diastolic velocities were decreased significantly in the central retinal artery (P < 0.02 and P < 0.01, respectively), temporal posterior ciliary artery (P < 0.05 and P < 0.03, respectively), and nasal posterior ciliary artery (P < 0.03 and P < 0.02, respectively). Pourcelot's ratio was significantly increased in the central retinal artery (P < 0.01), temporal posterior ciliary artery (P < 0.02), and nasal posterior ciliary artery (P < 0.02) after retrobulbar injection of lidocaine with epinephrine. CONCLUSIONS: These results indicate that one drop of topical epinephrine has little or no effect on the retrobulbar circulation, whereas retrobulbar injection of anesthetic solution containing lidocaine with epinephrine significantly alters retrobulbar hemodynamics in the monkey eye.
Administration, Topical↗
Optic disc hemorrhages and progression of glaucoma.
PURPOSE: To assess progressive changes of the optic nerve head and visual fields in patients with glaucoma and ocular hypertension after optic disc hemorrhage. METHODS: The authors reviewed the charts of 91 patients with 121 disc hemorrhages who had a mean follow-up of 41.9 +/- 3.6 months. The frequency of visual field and optic nerve head changes in these patients was studied. RESULTS: The mean intraocular pressure at the examination when the disc hemorrhage was noted was 18.9 +/- 0.5 mmHg. Overall, 64 (63%) of 101 eyes showed progressive changes of visual fields after disc hemorrhage, compared with 24 (24%) of 101 control eyes (P < 0.0005). Similarly, 56 (79%) of 71 eyes showed progressive changes of optic nerve head contour by masked evaluation of stereophotographs, compared with 16 (22%) of 71 control eyes (P < 0.0005). Eyes with disc hemorrhage showed significantly greater progression of visual field defects in patients with open-angle glaucoma (P < 0.001), low-tension glaucoma (P < 0.05), and ocular hypertension (P = 0.0067) compared with control eyes matched by age, follow-up time, and diagnosis. Similarly, progressive changes of optic nerve head contour were observed more often in eyes after disc hemorrhage in patients with open-angle glaucoma (P < 0.0005), low-tension glaucoma (P < 0.025), and ocular hypertension (P < 0.005), compared with controls. The mean time interval to progression after disc hemorrhage was observed was 16.8 +/- 2.0 months for visual field changes and 23.8 +/- 2.9 months for optic nerve head changes. In eyes with disc hemorrhage, 27 (22%) of 121 had recurrent hemorrhages at a mean interval of 21.5 +/- 2.9 months after previous hemorrhage. The most common site of disc hemorrhage was the inferotemporal quadrant. Eyes with disc hemorrhage that occurred on the temporal side of the optic nerve head had a significantly lower intraocular pressure (P < 0.02) and greater progressive changes of the optic discs (P < 0.001) compared with eyes with hemorrhage on the nasal side. CONCLUSION: The authors' results indicate that disc hemorrhages in eyes with glaucoma or ocular hypertension often are associated with progressive changes of the optic nerve head and visual fields.
Adult↗
Clinical experience with the Baerveldt glaucoma drainage implant.
PURPOSE: To assess clinical outcomes in patients who were treated with the Baerveldt glaucoma drainage implant. METHODS: The authors performed a retrospective multicenter study of 100 patients (103 eyes) with medically uncontrollable glaucomas who underwent a one-stage implantation with either the 200-, 250-, 350-, or 500-mm2 Baerveldt implant. The authors defined surgical success as 5 mmHg less than intraocular pressure less than 22 mmHg without additional glaucoma surgery and without loss of light perception. RESULTS: With a mean follow-up of 13.6 +/- 0.9 months (range, 4-37 months), 74 eyes (71.8%) had successful outcomes. Cumulative life-table success rates were 90.3% at 3 months (n = 103), 72.6% at 6 months (n = 84), and 60.3% at 24 months (n = 34). Intraocular pressure (IOP) was reduced from a mean of 38.5 +/- 1.4 mmHg with 2.2 +/- 0.1 antiglaucoma medications to 15.1 +/- 0.8 mmHg (P < 0.0005) with 0.5 +/- 0.1 antiglaucoma medications (P < 0.0005). Visual acuity was improved or remained within one line of the preoperative visual acuity in 90 eyes (87.4%). Complications occurred in 74 eyes (71.8%). A significant portion of these complications (45%) was transient, resolving without any intervention. Only 8% were serious sight-threatening complications. The most common complications included shallow anterior chamber or hypotony (32%), choroidal effusion or hemorrhage (20.4%), corneal decompensation or edema (17.5%), hyphema (14.1%), and tube obstruction (12.6%). CONCLUSION: The Baerveldt implant is effective in lowering the IOP in patients with intractable glaucomas. Hypotony and other complications are common, which also have been reported in other nonvalved glaucoma drainage implants. However, the majority of these complications did not affect surgical outcome.
Adolescent↗
Statistical techniques in ophthalmic journals.
Over the years, the use of statistics to evaluate experimental data in ophthalmology has increased. The present study sought to assess the frequency and types of statistical techniques used in ophthalmic journals. We reviewed 974 original articles from the Archives for 1970, 1980, and 1990; the American Journal of Ophthalmology for 1990; and Ophthalmology for 1990. Of the 592 articles reviewed for 1990, 391 (66.0%) contained statistics, with measures of central tendency most commonly used (385 articles [65.0%]), followed by dispersion (298 [50.3%]), t test (120 [20.3%]), and contingency tables (98 [16.6%]). A reader familiar with 10 statistical techniques would have "statistical accessibility" to 526 (88.9%) of 1990 articles. A statistically significant difference was found in the percentage of articles containing statistical methods among the journals (P = .0003; Archives, 75.3%; Ophthalmology, 66.8%; and American Journal of Ophthalmology, 55.2%).
Animals↗
Dependence of proteoglycan induced arthritis in BALB/c mice on the development of autoantibodies to high density proteoglycans.
BALB/c mice were immunised with high or low density native human cartilage proteoglycans, or the respective core proteins obtained from chondroitin ABC lyase digestion. Mice injected with high density native proteoglycans developed arthritis whereas mice injected with low density proteoglycans or with core proteins did not. Analysis of the immune response by enzyme linked immunosorbent assay (ELISA) and western blot showed a stronger and more polyspecific response in animals injected with low density proteoglycans compared with mice with arthritis which had been injected with high density proteoglycans. Autoantibodies to mouse high density proteoglycans were only present in mice injected with native human high density proteoglycans, however. The data suggest that an arthritogenic epitope lies within the glycosaminoglycan rich region of the native proteoglycan molecule, which may induce an autoantibody response and subsequently arthritis in BALB/c mice.
Animals↗