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PubMed1982

[Modification of the 2 loop-Medallion-lens (author's transl)].

The loop diameter was enlarged from 7.6 to 8.5 mm and the holes for the iris fixation suture were placed upwards towards the margin of the haptic. This resulted in a marked decrease of loop-dislocations when comparing two groups with 80 (old lens) and 120 eyes (new lens) respectively. Spontaneous loop-dislocations occurred in 5% with the original lens and in 0.8% with the altered lens, iatrogenic dislocations, i.e. following the instillation of a weak mydriatic, occurred in 10% with the older typ but only in 0.8% with the new lens.

Equipment Failure↗
PubMed1980

[Liindner's method of cylinder retinoscopy without theory].

Brief description of Lindner's cylinder retinoscopy for practical application: The main criteria of this accurate method for checking refraction are the direction, shape, speed and brightness of the retinoscopic phenomena moving in the pupil of the examined eye. To determine astigmatism the use of plus cylinders is recommended. Difficulties may be due to the optical aberration at the periphery of a wide pupil, to a scissors phenomenon, and to optical irregularities of the senile lens, corneal opacities etc. In many cases retinoscopy can be performed well without using mydriatics and cycloplegics, respectively. Children must not be overstrained. Generally, final subjective checking is crucial for the prescription of corrective glasses. Mastery of Lindner's cylinder retinoscopy enables the eye specialist to keep refractometry with simple aids, as an essential part of the ophthalmological diagnosis, in his own hands, against the increasing claim of optometrists and opticians.

Adult↗
PubMed1980

[Diagnosis and treatment of neuroparalytic zoster keratitis (author's transl)].

In severe zoster keratitis many pathogenic factors are involved. In addition to viral manifestations, the cornea is often affected by anterior uveitis or secondary glaucoma. Neuroparalytic keratitis causes lowered blinking frequency and decreased tear secretion. In addition, zoster ulcerations of the upper lid margin mechanically disturb reformation of the tear film and weaken the lipid layer by necrosis of the Meibomian glands. Ointments reduce break-up time and parasympathicolytic mydriatics further decrease tear secretion. When the average time between two blinks is shorter than the tear film break-up time, a "dry eye" condition usually develops. The appropriate treatment in such cases is thorough prevention of evaporation.

Bandages↗
PubMed1999

The VECAT study: methodology and statistical power for measurement of age-related macular features. Vitamin E, Cataract, and Age-related Maculopathy Study.

PURPOSES: (1) To develop the methodology for the grading of macular one-frame stereoslides and to assess the reliability of the system. (2) To determine the prevalence of soft drusen (> 63 microm) and pigment abnormalities synonymous with age-related maculopathy (ARM) at baseline, in a clinical trial of volunteers aged between 55 and 80 years of age. (3) To ascertain the power of the study to detect the 4-year incidence and progression of ARM in vitamin E versus placebo treated participants, given the baseline prevalence. METHODS: The 1204 participants enrolled in the Vitamin E, Cataract, and Age-related Maculopathy Study (VECAT) had colour stereoslides of their fundus taken using the Nidek 3-DX mydriatic fundus camera. The stereoslides were graded by two masked graders according to the "International Classification System for ARM and AMD". Assessment of inter- and intra-observer reliability was carried out on a regular basis on 15% of randomly selected slides. Anticipated rates of incidence and progression were based on results reported by the Beaver Dam Eye Study and the Chesapeake Bay Waterman Study. Power estimations were determined using the "nQuery Advisor" software program. Analyses were carried out on the worse affected eye. RESULTS: Inter-observer reliability was moderate to substantial (Kappa 0.5-0.88) whilst intra-observer agreement was high (0.6-1.0). The prevalence of any soft drusen was 32%. Significant associations were found between soft large indistinct drusen, hypopigmentation, hyperpigmentation and age (p = 0.0001, 0.024 and 0.0001, respectively). The study has at least 87% power to detect an odds ratio equal to two for the progression of soft distinct, soft indistinct, hyperpigmentation and hypopigmentation. CONCLUSIONS: The VECAT study methodology appears to be highly reliable and to have sufficient power to detect the differences in the four-year progression of soft distinct and indistinct drusen and pigment abnormalities between the treatment groups.

Aged↗
PubMed2002

Digital photographic screening for diabetic retinopathy in the James Bay Cree.

This study evaluates a single, 45-degree fundus image from a non-mydriatic camera for the triage of subjects at risk for diabetic retinopathy. A complete retinal assessment by a retina specialist was the main comparator for the camera. Inter-observer agreements were calculated for the reading of digital images with different grades of retinopathy. Two hundred eyes of 100 consecutive subjects were evaluated as part of the James Bay diabetic retinopathy screening project; 62% of subjects had no retinopathy, 12% had microaneurysms only, 24% had non-proliferative retinopathy, 5% had clinically significant macular edema (CSME), and 2% had proliferative disease (PDR). The Kappa statistic for two independent observers was 0.85 (p < 0.001) for the identification of retinopathy from the digital images. The sensitivity of the digital camera for the evaluation of any retinopathy was 84.4%, for CSME and/or PDR it was over 90%. The use of a single digital retinal image for the evaluation of diabetic retinopathy was performed with a high degree of inter-observer concordance and a high degree of sensitivity.

Adult↗
PubMed2006

Anterior uveitis and meningococcemia: a case report.

PURPOSE: To describe a case of meningococcemia with anterior uveitis. METHODS: Observational case report. RESULTS: A 38-year-old woman developed meningococcal septicemia caused by Neisseria meningitidis type B. During her admission, she had pain in her left eye, inflammatory cells, and a fibrinous exudate in the anterior chamber and multiple posterior synechiae, all in the context of an anterior uveitis. She was treated with topical steroids and mydriatics with resolution of ocular inflammation. CONCLUSIONS: This case illustrates the possible association between anterior uveitis and a meningococcal septicemia, and the need for careful ophthalmologic examination when a red eye develops in this clinical context.

Adult↗
PubMed2005

Methods for a population-based study of myopia and other eye conditions in school children: the Sydney Myopia Study.

PURPOSE: The Sydney Myopia Study will establish the prevalence of myopia and other eye diseases in a large representative sample of Sydney school children. It will also examine the relationship between myopia and potential modifiable risk factors and will assess potential gene-environment interactions by examining parents and siblings. METHODS: The target population is a stratified random cluster sample of 1750 Year 1 (age 6 years) and 1500 Year 7 (age 12 years) students from Sydney metropolitan schools. Procedures (comprehensive parent-administered questionnaire and examination) involve standardized protocols to allow for comparison with international population-based data. Examinations include a detailed assessment of visual acuity, cover testing for strabismus, identification of amblyopia, slit-lamp examination, non-contact ocular biometry and cycloplegia (cyclopentolate) followed by autorefraction, optical coherence tomography, retinal thickness measurement, digital mydriatic retinal photography and aberrometry. CONCLUSIONS: The Sydney Myopia Study design and methodology will ensure valid findings on ocular development and health in a large representative sample of Sydney school children, for comparison with other population-based refraction data.

Adolescent↗
PubMedDate not supplied

Teleophthalmology link between a primary health care centre and a reference hospital.

We have evaluated a teleophthalmology service linking a primary health care centre and an eye clinic at a reference hospital. General practitioners at the primary care centre serving a population of 15,000 and ophthalmologists at the reference hospital participated in this study. Eye fundus digital images were taken from 278 eye fundi of 139 consecutive patients with clinical conditions that could potentially produce fundus alterations. Fundus images were obtained with a non-mydriatic fundus camera (Canon CR6-45M) and were electronically sent reference hospital where ophthalmologist inspected the images and returned the diagnosis. In 18 patients (13%) the images did not have good enough quality to exclude eye fundus lesions. In 24 patients (17%) clear eye fundus alterations were found in at least one eye. In 14 patients (10%) there were image features suggesting retinal alterations that could not be confirmed by image inspection. Media opacity (13 eyes, 5%, seven patients, 5%) was the most common cause of poor image quality. The most difficult assessment was the evaluation of optic nerve head cupping. Retinal oedema was not observable in the digital images. In our experience teleopthalmology services seem to be an effective alternative for eye fundus diagnosis and patient follow-up.

Computer Communication Networks↗
PubMed1985

Pilocarpine mydriasis in mice.

In several rodent species pilocarpine and oxotremorine produce mydriasis, rather than the miosis which is characteristic of most other species. We have established that pilocarpine is a mydriatic drug in mice, a species in which the action has previously not been described, and that this effect occurs after local ocular, intraperitoneal (IP) or intracerebroventricular (ICV) application. Arecoline produces miosis or mydriasis (depending on dose) following direct ocular application but mild mydriasis after IP or ICV injection. Atropine also produces mydriasis in mice, and the effect of pilocarpine is additive with that produced by atropine and is not antagonized by antihistamines. Direct ICV pilocarpine injection produces mydriasis at doses equivalent to those used systemically. Pilocarpine mydriasis probably results from inhibition of parasympathetic activity.

Animals↗
PubMed1985

Ocular effects of adrenergic stereoisomers in the rabbit.

Because of the need to develop ocular hypotensive agents with low incidence of side effects, the dextrorotatory enantiomers of adrenergic agents have prompted some attention. In the present study, the relative potency and efficacy of various adrenergic stereoisomers with respect to their ocular hypotensive and mydriatic effects have been determined after topical administration to conscious rabbits. The relative order of potency was found to be, iris: 1-epinephrine much greater than d-epinephrine congruent to 1-norepinephrine congruent to dl-alpha-methyl-norepinephrine greater than dl-alpha-methyl-epinephrine greater than d-norepinephrine; intraocular pressure (IOP): l-epinephrine greater than dl-alpha-methyl-epinephrine greater than d-epinephrine greater than dl-alpha-methyl-norepinephrine greater than d-norepinephrine congruent to 1-norepinephrine. The pupil and the initial ocular hypertensive responses clearly demonstrated the phenomenon of stereoselectivity of adrenergic stimulants, in that the 1-form was relatively more potent than the d-form. However, such order of potency does not seem to hold for IOP. The apparent discrepancy and reversal of order of potency for IOP responses may be related to the hypothesis that the net ocular hypotensive effect of adrenergic agents is the summation of the initial hypertension and the delayed hypotension produced by these agents. It is anticipated that the results of the present study may improve our understanding of ocular pharmacology of adrenergic stereoisomers. The ability to separate the dose-response profiles of pupillary and IOP effects of these agents may have potential therapeutic significance and thus warrants further investigation in other species.

Animals↗
PubMed1985

Alpha-adrenergic receptors in rabbit eyes.

The IOP and pupil response to alpha-adrenergic agonists and blockers was studied in albino rabbits. Topical ocular application of solutions of methoxamine (alpha 1) and oxymetazoline (alpha 2) caused dose-related early rises in IOP which were inhibited by pretreatment with prazosin, an alpha 1-blocker, or with yohimbine, an alpha 2-blocker. Although both prazosin and yohimbine have ocular hypotensive activity, the effect on the early IOP rise did not appear to be related to this action. Prazosin and yohimbine also inhibited the early IOP rise after treatment with clonidine, a second alpha 2-agonist. Surgically sympathectomized rabbits showed little or no hypersensitivity to methoxamine or oxymetazoline when compared to non-operated normal rabbits. However the treated ipsilateral eyes showed a much greater increase in IOP than the treated contralateral eyes. There was little difference in the IOP response between clonidine-treated ipsilateral and contralateral eyes. Methoxamine and oxymetazoline caused dose-related increases in the pupil diameter which were blocked by the nonselective alpha-blocker phentolamine but not by prazosin (alpha 1) or yohimbine (alpha 2). This study suggests: 1) That the early IOP rise after treatment with alpha-agonists is due to stimulation of postsynaptic alpha 1-receptors, possibly located in superficial blood vessels in the anterior segment of the eye; 2) The mydriatic response to alpha-agonists appears to be mediated by alpha-receptors which differ from the classical alpha 1 and alpha 2 subtypes.

Adrenergic alpha-Agonists↗
PubMed1987

Autonomic drug effects after chronic lowering of ocular cholinergic input. I. Pupillary responses.

Cholinergic input to the anterior segment of the eye was chronically lowered by ciliary ganglionectomy in cats. Experimental eyes developed supersensitivity to the miotic effects of pilocarpine. In addition, these parasympathetically denervated eyes exhibited a moderate subsensitivity to the mydriatic effects of norepinephrine, epinephrine, and isoproterenol. Iris preparations accordingly afford the unique opportunity to study the two opposite extremes of normal drug sensitivity simultaneously in the same tissue.

Animals↗
PubMed1989

Hyperglycemia does not modify the pupillary effects of mu and kappa opiate agonists in mice.

The effects of mu and kappa opiate agonists were assessed on the pupillary size in normoglycemic and hyperglycemic conditions in mice. The mu agonists used were, morphine (10, 30 and 100 mg/kg), fentanyl (50, 100 and 150 micrograms/kg) and sufentanil (5, 10 and 20 micrograms/kg). The highly selective kappa opiate agonists used were, U-50488H and U-69593 (30 mg/kg). Chronic hyperglycemia was induced by streptozotocin injection (200 mg/kg i.p) 7-8 days before the experiment. Acute hyperglycemia was induced by intraperitoneal glucose (5 g/kg i.p) injection at the time of subcutaneous injection of opiates. In the normoglycemic mice, the mu agonists produced significant mydriasis (P less than 0.05), while kappa agonists had no effect on the pupil. However, both acute and chronic hyperglycemic condition did not affect the mydriatic ratio of the mu opiate agonists. These results indicate that mu opiate receptors induce mydriasis in mice and suggest that the hyperglycemia is not the mechanism involved in the opiate induced mydriasis in mice. With the dose of kappa agonists used, the involvement of kappa receptors in the pupillary effects in mice were not clear. These results support the hypothesis that hyperglycemia is not the primary mechanism for the altered sensitivity of opiates in the animal models of diabetes.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1994

Designing safer ophthalmic drugs by soft drug approaches.

There are two major novel metabolism-based drug design concepts which have significant advantages when used in the design of safe, specific ophthalmic drugs. One is based on predictable enzymatic activation processes by enzymes found exclusively or preferentially at the site of action--in this case, within the eye, primarily in the iris-ciliary body. The second major retrometabolic design technique involves soft drug approaches. Among the various soft drug design strategies, it was found that the "inactive metabolite" and the "soft analog" approaches are the most useful for designing safe and selective ophthalmic drugs. In the first case, the design process starts with a known (or predicted) inactive metabolite (Mi) of the drug (D). This Mi is then structurally modified in the "chemical activation" stage to the soft drug (SD), which is isosteric and/or isoelectronic with D to produce activity at the target receptors, similar to that of D. By design, however, SD is also subject to a facile, predictable (generally hydrolytic) metabolism leading in one step to the starting inactive Mi. As this deactivation takes places everywhere in the body, the desired activities are produced virtually exclusively at the target site at or near the place of application. Successful use of this general concept has led to soft beta-blockers as safe antiglaucoma agents, soft anticholinergics as short acting mydriatic agents, and soft corticosteroids as a type of novel, safe anti-inflammatory agents, which due to their unique design, do not elevate intraocular pressure IOP and do not produce other systemic and local side effects.

Administration, Topical↗
PubMed1994

Mucoadhesive ophthalmic vehicles: evaluation of polymeric low-viscosity formulations.

A series of polyanionic natural or semi-synthetic polymers (polygalacturonic acid, hyaluronic acid, carboxymethylamylose, carboxymethylchitin, chondroitin sulfate, heparan sulfate and mesoglycan) were evaluated as potential mucoadhesive carriers for ophthalmic drugs. Solutions containing cyclopentolate (CY) or pilocarpine (PI) as salts (or polyanionic complexes) with the acidic polymers, all showing a low viscosity, were tested for miotic (resp. mydriatic) activity in albino rabbits. In the case of some polymeric complexes, small but significant increases of the areas under the activity vs. time curves (AUC) over reference cyclopentolate hydrochloride (CYHC1) or pilocarpine nitrate (PINO3) vehicles, and significant AUC decreases after removal of precorneal mucin by treatment with N-acetylcysteine were observed. A correlation was found between these data, considered indicative of the occurrence of a mucoadhesive interaction "in vivo", and "in vitro" viscometric data expressing the polymers-mucin force of interaction. The advantages and limitations of the mucoadhesive non-viscous approach in the formulation of ophthalmic vehicles are presented and discussed.

Adhesiveness↗
PubMed2004

Alpha2-adrenoceptors do not mediate reflex mydriasis in rabbits.

The aim of this study was to identify receptors that mediate reflex mydriasis in pentobarbital-anesthetized rabbits, in which the cervical sympathetic nerve was sectioned unilaterally. Voltage-response curves of pupillary dilation were generated bilaterally by stimulation of the sciatic nerve. Evoked mydriatic responses were mediated mainly by efferent parasympathetic innervation, and, to a lesser extent, by sympathetic innervation. The alpha-adrenergic antagonist, phenoxybenzamine (0.3 mg/kg, intravenously (i.v.)), antagonized mydriasis of the neurally intact eye, but not that on the sympathectomized side. The alpha2-adrenergic antagonist, RS 79948 (0.3 mg/kg, i.v.), potentiated mydriasis of the normal eye, but was without either a potentiating or inhibitory effect on the mydriasis of the sympathectomized eye. In addition, the dopamine-receptor antagonist, haloperidol (1 mg/kg, i.v.), inhibited evoked mydriasis of the sympathectomized eye. These results suggest that, unlike some other species (cats and rats), alpha2-adrenoceptors do not mediate reflex mydriasis elicited by sciatic-nerve stimulation in the rabbit, and support the previous finding in humans that dopamine receptors may mediate this response.

Adrenergic alpha-2 Receptor Antagonists↗
PubMed2005

A modeled economic analysis of a digital tele-ophthalmology system as used by three federal health care agencies for detecting proliferative diabetic retinopathy.

The objective of this study was to compare, using a 12-month time frame, the cost-effectiveness of a non-mydriatic digital tele-ophthalmology system (Joslin Vision Network) versus traditional clinic-based ophthalmoscopy examinations with pupil dilation to detect proliferative diabetic retinopathy and its consequences. Decision analysis techniques, including Monte Carlo simulation, were used to model the use of the Joslin Vision Network versus conventional clinic-based ophthalmoscopy among the entire diabetic populations served by the Indian Health Service, the Department of Veterans Affairs, and the active duty Department of Defense. The economic perspective analyzed was that of each federal agency. Data sources for costs and outcomes included the published literature, epidemiologic data, administrative data, market prices, and expert opinion. Outcome measures included the number of true positive cases of proliferative diabetic retinopathy detected, the number of patients treated with panretinal laser photocoagulation, and the number of cases of severe vision loss averted. In the base-case analyses, the Joslin Vision Network was the dominant strategy in all but two of the nine modeled scenarios, meaning that it was both less costly and more effective. In the active duty Department of Defense population, the Joslin Vision Network would be more effective but cost an extra 1,618 dollars per additional patient treated with panretinal laser photo-coagulation and an additional 13,748 dollars per severe vision loss event averted. Based on our economic model, the Joslin Vision Network has the potential to be more effective than clinic-based ophthalmoscopy for detecting proliferative diabetic retinopathy and averting cases of severe vision loss, and may do so at lower cost.

Cost-Benefit Analysis↗
PubMed1988

Effects of ketanserin on blood pressure and platelet aggregation in elderly men with mild hypertension.

Thirteen men, age 60 +/- 2 years (mean +/- SEM) with mild hypertension, 151 +/- 4/95 +/- 3 mm Hg, completed a randomized, double-blind, placebo-controlled crossover trial of ketanserin therapy. In comparison to placebo, ketanserin treatment at 40 mg bid for 6 weeks lowered systolic and diastolic blood pressure, 148 +/- 4/92 +/- 3 vs. 140 +/- 6/86 +/- 3 mm Hg, P = 0.19/0.02. The rate of platelet aggregation in response to ADP and epinephrine was unchanged while the response to serotonin was greatly diminished. Neither the systemic pressor response nor the pupillary mydriatic response to phenylephrine was significantly altered. Plasma norepinephrine concentration declined significantly. Ketanserin reduced blood pressure, particularly the diastolic component, in elderly men with mild hypertension. While antagonism of serotonin's effects on platelet aggregation was evident, blockade of alpha 1-receptor-mediated events was not apparent. The results suggest that during chronic therapy the antihypertensive effects of ketanserin were mediated by serotonergic blockade and a possible lytic effect on sympathetic drive. The dual effects of ketanserin on blood pressure and platelet aggregation may be beneficial in reducing cardiovascular complications in hypertensive patients.

Adult↗