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PubMed1979

Potentiation of the mydriatic effect of norepinephrine in the rabbit after monoamine oxidase inhibition.

Dose-response curves of pupillary dilation after topical administration of norepinephrine or methoxamine have been determined in rabbits after chronic inhibition of ocular monoamine oxidase by treatment with pargyline or pheniprazine. Eyes treated with either monoamine oxidase inhibitor showed an enhanced responsiveness to the mydriatic effect of norepinephrine given either topically or intravenously. Increments in pupil size of the treated and control eyes in response to methoxamine applied topically, on the other hand, were the same. These results suggest that monoamine oxidase may play a role in the iris as one factor influencing the concentration of norepinephrine at the receptors.

Animals↗
PubMed1985

Minimizing risk of adverse reactions to mydriatic agents in binocular indirect ophthalmoscopy.

To minimize the risk of adverse side effects from mydriatics during binocular indirect ophthalmoscopy, a procedure was developed which intentionally starts with a dose significantly less than an ED99. Using a clinically effective diameter of greater than 7 mm as a criterion, I found that 1 drop of 0.5% tropicamide (T) constituted an ED74 (N = 46). When 1 drop of 2.5% phenylephrine (P) was added, this increased to an ED93 (N = 27). If present results can be generalized, then 1 drop of T, supplemented at 30 minutes with 1 drop of P, if necessary, should produce satisfactory dilatation in approximately 90% of the subjects.

Adult↗
PubMed1994

Comparative use of various mydriatic drugs in kestrels (Falco tinnunculus).

The mydriatic effect of 3 curare-like neuromuscular blocking agents was tested in European kestrels (Falco tinnunculus) after topical application. Alcuronium chloride (5 mg/ml) was found to be effective at a dose of 1 drop (20 drops = 1 ml) administered twice at a 15-minute interval. Mydriasis was achieved at t = 26 +/- 11 minutes, maximal effect was reached at t = 60 +/- 39 minutes, and sufficient mydriasis ended at t = 364 +/- 134 minutes. Nevertheless, side effects, including temporary full paralysis in 1 bird, indicated that this drug should not be used. Pancuronium bromide (2 mg/ml) had an inconsistent effect on each bird at a dose of 2 drops administered twice at 15-minute intervals, and total mydriasis was not reached in 5 of 8 birds. Mydriasis was achieved at t = 34 +/- 11 minutes, maximal effect was reduced and reached at t = 43 +/- 13 minutes, and sufficient mydriasis ended at t = 90 +/- 39 minutes. Vecuronium bromide (4 mg/ml) was administered at a dose of 2 drops, 3 times, at 15-minute intervals. Mydriasis was achieved at t = 23 +/- 8 minutes, maximal effect was reached at t = 65 +/- 12 minutes, and sufficient mydriasis ended at t = 253 +/- 65 minutes. Side effects were not detected. Vecuronium bromide should be used in raptorial birds whenever retinal examination requires fundoscopy.

Alcuronium↗
PubMed1977

The mydriatic effect of tropicamide on light and dark irides.

Tropicamide 0.5% was topically applied to the eyes of thirteen subjects to study its effectiveness as a mydriatic. A comparison was made between the subjects with light colored irides and those with dark brown irides, and also between those who had worn contact lenses previous to dilation and those who had not. Results indicate that a minimum pupil size of 6 mm was achieved within 25 minutes after instillation and this dilation was independent of iris pigmentation. Typically, IOP was reduced during dilation with tropicamide.

Adult↗
PubMed1992

The follow-up of patients screened for glaucoma with non-mydriatic fundus photography.

In order to evaluate the value of photographic screening in predicting progressive glaucomatous damage, we re-examined 26 subjects 5 years after the initial screening. Of the 26 patients 16 had typical glaucomatous optic disc and visual field abnormalities (n = 7), retinal nerve layer damage (n = 6), or other risk factors of glaucoma (n = 3). In 10 of 26 patients suspected of having glaucoma, no abnormalities were initially confirmed. Of the 16 eyes with initially abnormal findings, 10 (63%) showed progressive changes during the 5-year follow-up period. The 10 initially suspected cases have remained healthy throughout the follow-up, giving a false positive rate of 5.5%. The results of this study indicate that it is possible to identify correctly patients with progressive glaucomatous changes with a non-mydriatic fundus camera.

Female↗
PubMed1988

The bradycardic and mydriatic effects of chlordimeform and its demethylated analogs in the rat: antagonism by idazoxan but not by prazosin.

Pupillary and cardiac responses to i.v. injections of chlordimeform (CDM, 0.3-10 mg/kg), a formamidine insecticide, and its metabolites demethylchlordimeform (DCDM, 0.03-1 mg/kg) and didemethylchlordimeform (DDCDM, 0.1-3 mg/kg) were studied in rats anesthetized with pentobarbital. Both CDM and DCDM induced a dose-dependent mydriasis and bradycardia and DCDM was 10 times more potent than CDM in causing these effects. In contrast, DDCDM did not induce a mydriasis or bradycardia. The alpha 2-adrenoreceptor antagonist, idazoxan (0.2 mg/kg, i.v.) abolished or reduced CDM- and DCDM-induced mydriasis and bradycardia, whereas the alpha 1-adrenoreceptor antagonist, prazosin (1.5 mg/kg, i.v.) did not change these effects of CDM and DCDM. SKF 525-A (50 mg/kg, i.p.), an inhibitor of enzymatic demethylation, administered 10 min before the first dose of CDM, failed to reduce the effects of CDM. The results suggested: 1) the mydriatic and bradycardic effects of CDM and DCDM are mediated by alpha 2-adrenoreceptors, 2) the monodemethylation of CDM increases its alpha 2-adrenoreceptor agonistic activities, but the didemethylation of CDM abolishes these activities, and 3) CDM can exert alpha 2-adrenoreceptor agonistic activities without undergoing a demethylation process.

Amidines↗
PubMed1993

The quality of photographs produced by the non-mydriatic fundus camera in a screening programme for diabetic retinopathy: a 1 year prospective study.

A prospective study was performed on the quality of photographs produced by the non-mydriatic fundus camera used in a hospital-based screening programme for diabetic retinopathy. In 1 year 981 binocular patients were photographed. A photograph of acceptable quality was obtained from 90.5% of eyes and 84.4% of patients had an acceptable photograph of both eyes. The photograph of the second eye was more often unacceptable than that of the first. This tendency was significant in females (p = 0.0196) and when considering the sexes together (p = 0.0044), but not significant in males (p = 0.1042). Photographs of unacceptable quality were obtained significantly more often in patients aged over 55 years for both right and left eyes (p = 0.001). An overall improvement in photographic quality might be achieved by allowing full recovery of flash-induced pupil constriction before taking the second photograph and by dilating those aged over 55 years.

Adult↗
PubMed1992

Screening for diabetic retinopathy in a widely spaced population using non-mydriatic fundus photography in a mobile unit. Tayside Mobile Eye Screening Unit.

A screening project was established to assess the prevalence and severity of retinopathy in diabetic patients in Tayside (area: 3000 square miles, population: 390,000). A questionnaire was used to examine patient acceptability. Of 2112 patients photographed during the first year, 32% had abnormal photographs; 20.2% had diabetic retinopathy; 7.4% cataracts; 4.6% non-diabetic eye disease. Among this patient population, 73% were registered at a hospital diabetic clinic. The overall prevalence of diabetic retinopathy was similar between the two groups (hospital 23% vs non-hospital 20%). The prevalence of severe diabetic retinopathy was also similar (hospital 8.5% vs non-hospital 10%). This had been previously unrecognized or incorrectly defined in 6.5% of those not attending a hospital diabetic clinic, compared to 3.7% attending the hospital clinic (p less than 0.01). A favourable response to the service was indicated by 40% of patients with 7% unfavourable and 41% uncommitted. Non-mydriatic fundal photography housed in a mobile unit is a practical and effective method of assessing diabetic retinopathy. It is particularly suitable for screening in a widely spread population.

Diabetic Retinopathy↗
PubMed1995

A report on the use of technician ophthalmoscopy combined with the use of the Canon non-mydriatic camera in screening for diabetic retinopathy in the community.

This paper describes a general practice based diabetic retinopathy screening service employing a technician trained in direct and indirect ophthalmoscopy and taking photographs with a Canon CR3 45 NM non-mydriatic polaroid camera analysed by a consultant ophthalmologist to provide a comparison with the screener's opinion. Prospective data is presented from the first 1050 patients screened for diabetic retinopathy in the Exeter Health Authority area. Analysis of data collected showed a prevalence of diabetic retinopathy in the screened population of 27%, 14% previously undetected with a 0.5% prevalence of sight-threatening retinopathy. There was almost complete agreement between ophthalmoscopy findings and the consultant analysis of photographs. Screening costs were calculated at 10.38 pounds per patient screened. A specially trained non-medically qualified technician can provide a good quality cost-effective screening service for diabetic retinopathy within a primary care setting.

Adolescent↗
PubMed1989

Influence of thymoxamine eye-drops on the mydriatic effect of tropicamide and phenylephrine alone and in combination.

In a preliminary experiment in 12 healthy volunteers, one drop of thymoxamine 0.5% instilled into the conjunctival sac completely reversed the mydriasis produced by phenylephrine 2.5%, 5% and 10% after 20 minutes. In a second study in eight volunteers, thymoxamine 0.5% completely prevented the mydriasis produced by phenylephrine 2.5% and produced a miosis. It also completely reversed the mydriasis produced by tropicamide 0.5%. The mydriatic effect of tropicamide 0.5% plus phenylephrine 2.5%, however, was not completely reversed by thymoxamine 0.5% over a period of 180 minutes. Phenylephrine, tropicamide and thymoxamine are freely available for use by registered optometrists.

Adolescent↗
PubMed1985

Mydriatic drugs for diabetic patients.

A comparative study in healthy subjects and diabetic patients of the mydriatic response to topical tropicamide 0.5% with and without added phenylephrine 10% is reported. The findings indicate that diabetic pupils respond relatively poorly to tropicamide alone but adequately and completely to the drug combination. The pupils of diabetic patients whose eyes had previously received laser treatment dilated less than those from untreated eyes by a small but significant extent. This combination of drugs is recommended for all diabetic patients to provide an adequate mydriasis with a minimum of postclinic accommodative paralysis.

Accommodation, Ocular↗
PubMed1989

Effect of cataract extraction on the pupil response to mydriatics.

Pupil diameters in the dark, in the light, and after mydriasis with tropicamide+ phenylephrine have been measured in 25 patients before and six months after cataract surgery. The aphakic pupil showed reduced mobility as evidenced by a smaller diameter in the and a larger one in the light. In patients who had intracapsular extraction or extracapsular extraction with intraocular lens implantation the pupils dilated less well than preoperatively. The difference in response to mydriatics is of practical importance in the assessment and treatment of peripheral retinal disorders in aphakic and pseudophakic eyes.

Aged↗
PubMed1986

Assessment of non-mydriatic fundus photography in detection of diabetic retinopathy.

Non-mydriatic retinal photography with later interpretation of the photographs was assessed as a screening method for the detection of diabetic retinopathy; when compared with an ophthalmologist's clinical assessment in a random group of 62 diabetic patients it was accurate (false negative 6.8%, false positive 2%) and sensitive (sensitivity 96%, specificity 98%). The assessment of further management required based on analysis of the photographs was 96.5% in agreement with the further management suggested by the ophthalmologist after direct clinical assessment of the patient. If this technique were used to screen patients in a typical diabetic clinic the predicted positive accuracy rate would be 84% and the predicted negative accuracy rate 99.5%.

Diabetic Retinopathy↗
PubMed1994

Mydriatic effect of ocular decongestants studied by pupillography.

The mydriatic effect of three ocular decongestants, containing 0.1% tetrahydrozoline hydrochloride, 0.3% chlorpheniramine maleate, and 0.05% tetrahydrozoline hydrochloride in combination with 0.3% pheniramine maleate, respectively, was evaluated in 10 healthy volunteers. The study was carried out using a single dose of the tested drug, instilling 2 drops in one eye and 2 drops of a placebo in the other. The papillary diameters were measured by photographic pupillography under basal conditions and 15, 30, 45, 60, 90, and 120 min after each treatment. Near and distance visual acuity and tonometry were evaluated under basal conditions and 50 and 95 min after instillation of drugs. No statistical significant differences between the treated and the control pupil diameters were found after instillation of 0.1% tetrahydrozoline hydrochloride or 0.3% chlorpheniramine maleate. The combination of 0.05% tetrahydrozoline hydrochloride with 0.3% pheniramine maleate caused a significant mydriasis from 30 min up to 120 min (p < 0.01 and p < 0.0005) after instillation, more pronounced in light irides. No local and systemic effects and no effects on visual acuity and ocular pressure were detected. On the basis of our results, it is possible to conclude that the persistent mydriatric action of the two-drug combination is due to a synergism; the use of these eyedrops should be avoided in subjects with narrow-angle glaucoma, light irides, narrow iridocorneal angle, and low anterior chamber for the risk of ocular pressure increase.

Adult↗
PubMedDate not supplied

Screening for glaucoma in a general population with the non-mydriatic fundus camera and the frequency doubling perimeter.

PURPOSE: To evaluate the usefulness of non-mydriatic fundus camera (NMFu-camera) and frequency doubling perimeter (FDP) for detecting glaucoma in a general population. METHODS: This prospective observational multicenter study consisted in screening for glaucoma in the populations of three Belgian cities. Intraocular pressure (IOP) was measured with non-contact pneumo-tonometer (NCT) and applanation tonometry (AT) if NCT IOP was > or = 17 mmHg. Visual field was screened with FDP (C-20-5) and digitized optic disc photographs (ODPs) were taken with NMFu-camera. FDP was considered abnormal if at least one defective point was found. ODPs were graded as normal or glaucomatous by consensus of three glaucoma specialists. Optic disc and visual field results were matched per eye. Subjects with known ocular hypertension and/or treated primary open angle glaucoma were excluded from the analysis. RESULTS: A total of 1620 subjects were included in the study. Their mean age was 63.2 years. AT IOP was > 21 mmHg in 8.2%. A total of 98.1% of ODPs could be interpreted. Glaucomatous optic discs were detected in 3.5% of the subjects. In this group only 24% had an AT IOP > or = 22 mmHg. FDP was abnormal in 44.5%. The sensitivity and specificity of FDP to identify patients with an optic disc graded as glaucomatous were 58.6% and 64.3% respectively. CONCLUSIONS: The combined use of the NMFu-camera and the FDP is a feasible method for an initial glaucoma mass screening. NMFu-camera may be a useful and quick method to screen for glaucomatous damage in a community. FDP in screening strategy was revealed to be not sensitive enough when setting the cut-off value at one defective test location. IOP measurements were confirmed to be a poor tool to detect glaucomatous damage.

Adult↗
PubMed1986

Mydriatic response to topical naloxone in opiate abusers.

Naloxone hydrochloride eyedrops 1 mg/ml dilated the pupils of 36 out of 47 opiate addicts on methadone maintenance treatment, without precipitation of acute withdrawal effects, but not those of healthy unmedicated subjects. The response in addicts was attenuated by certain ancillary treatments and by withdrawal of methadone treatment. The size of the response suggests some potential clinical use for topical naloxone as a diagnostic test of current opioid influence and possibility of physical dependence. The local mydriatic response, which was restricted to the treated eye, indicates that the effect of opiates on the pupil in man is determined, at least in part, by a peripheral action.

Adolescent↗
PubMed2003

[Screening for diabetic retinopathy: non-mydriatic retinal photography].

The screening of diabetic retinopathy is still largely insufficient and consequently, its management is often delayed. The various recommendations indicate a fundus examination at diabetes diagnosis and yearly thereafter. In France, this is far to be reached, and this situation is at risk of aggravation with the increasing number of diabetic patients and the decreasing number of ophthalmologists. New efficient tools, as the non-mydriatic cameras and digital photography, may allow a new network organisation for screening of diabetic retinopathy, with local screening sites linked to a centralised ophthalmological reading center where digital images could be transmitted. The various aspects of this screening and possibilities to improve the screening and early management of diabetic retinopathy are discussed in this paper.

Diabetic Retinopathy↗
PubMed2003

[Non mydriatic retinal camera: cost-effectiveness study for early detection of diabetic retinopathy].

BACKGROUND AND OBJECTIVE: Cost-effectiveness analysis (ACE) for application of fundoscopic photograph with non mydriatic retinal camera (Ffo-CNM) in early diagnostic of diabetic retinopathy (RD) compared with ophthalmoscopic view by pupillary dilation. PATIENTS AND METHOD: diabetic patients, older than 14 years, attended on three Health Primary Care Areas (n=1495). Effectiveness measurement: predictive value of a positive test (VPD) and correctly diagnosed cases. Cost measurement: total cost by patient. ACE: defined as expected cost by VPD case and as expected cost by correctly diagnosed case. The results were submitted to an analysis of sensitivity for the study main variables. RESULTS: Ffo-CNM presented 90.91% of sensitivity [95% CI, 69.4-98.4%], 78.21% of specificity [95% CI, 67.1-86.4%], 54.05% positive predictive value [95% CI, 37.1-70.2%] and 96.83% of negative predictive value [95% CI, 88-99.4%]. Effectiveness, defined as VPD case, was 15.4% for ophthalmoscopic view and 19.5% for Ffo-CNM, and defined as correctly diagnosed case, was 70% and 79.8%, respectively. Cost-effectiveness ratio: a) for health care system, the cost by VPD case was 52.62 euros for ophthalmoscopic view and 28.44 euros for Ffo-CNM and cost by correctly diagnosed case was 11.58 euros and 6.95 euros, respectively, and b) for the society, cost by VPD case was 100.13 euros for ophtalmoscopic view and 34.54 for Ffo-CNM and the cost by correctly diagnosed case was 22.03 euros and 8.44 euros respectively. CONCLUSIONS: If an introduction of a early detection of RD program for the entire diabetic population was decided the option to make it using Ffo-CNM would be the most efficient.

Adolescent↗