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At least 667 records · Page 37Linked to original sources
PubMed1993

Beta-cyclodextrins enhance bioavailability of pilocarpine.

Cyclodextrins have been used to improve drug solubility, stability and absorption for oral and parenteral administration. However, their potential for improving ocular drug delivery has received little attention. To evaluate the ability of hydroxypropyl-beta-cyclodextrins to improve ophthalmic drug bioavailability following topical administration, the miotic effect of topical solutions of pilocarpine was studied in New Zealand White rabbits. Pilocarpine varying in dose from 5 to 500 micrograms in the presence or absence of 5% cyclodextrin was administered (50 microliters) topically and the change in pupil diameter determined. These results demonstrated that pilocarpine alone or in the presence of cyclodextrin produces a dose-related reduction in pupil diameter. The addition of cyclodextrins produced a significant left-shift in the dose response curve, with an ED50 of 64 micrograms and 19 micrograms for pilocarpine and pilocarpine/5% cyclodextrin solutions, respectively. Studies in which the concentration of cyclodextrin was varied revealed that a one-to-one molar ratio of pilocarpine to cyclodextrin was sufficient to provide maximum increase in pilocarpine bioavailability. Electrophysiology and scanning electron microscopic studies demonstrated that cyclodextrin does not disrupt the normal ion transport currents, barrier properties or surface features of the corneal epithelium. Viscosity measurements indicated that difference in the viscosity of pilocarpine and pilocarpine/cyclodextrin solutions cannot account for increased bioavailability of pilocarpine. These data support the idea that the addition of cyclodextrin significantly improves the ocular bioavailability of pilocarpine. This enhanced bioavailability of pilocarpine does not appear to be due to a mechanism destructive to the epithelium or to an increase in vehicle viscosity.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1985

Circadian rhythm of the pupillary response to morphine and to naloxone.

Mice respond to morphine with characteristic mydriasis which is antagonized by naloxone. The present study presents data on the diurnal variation of these responses. The mydriatic response is at its highest level at 0800 and has a nadir at 2400. This effect is not influenced by ambient light conditions. The miotic response to naloxone in the morphine-dilated pupil is maximal between 1200 and 1600 and minimal at 0400. The curves of the responses to the two drugs, therefore, differ as do their acrophases. Pharmacokinetic factors are probably not responsible for the observed variations. It is speculated that these diurnal changes may reflect cyclic alteration in the affinity of the opiate receptors to agonists and antagonists, respectively, or in the number of available receptors.

Animals↗
PubMed1992

Variable angle retinal nerve fibre layer photography: a review.

Optic disc and retinal nerve fibre layer (RNFL) photography have been an integral part of the routine screening of glaucoma patients, ocular hypertensives and glaucoma suspects in Perth since 1979. During this period 60 degrees, 40 degrees, 30 degrees and 8 degrees angles of view were examined for potential use in RNFL photography. The degree of dilation and media opacity is highly variable in glaucoma patients because of the age group involved and the miotic therapy. It was found that the 30 degree angle of view gave the most consistent results for routine RNFL photography. Ocular hypertensives tended to be of a lower mean age and 40 degrees wide angle photography was possible but required two different photographic techniques and was not continued. Both 60 degrees and high-magnification RNFL photography are currently used only with selected patients for teaching and demonstration. A modified Hasselblad 120 roll film camera was used for high-resolution RNFL photography. The Hasselblad adaptors, high-resolution results and comparisons with wide-angle RNFL photographs are illustrated in this paper.

Fundus Oculi↗
PubMed1978

Herniated thoracic disc at T1-2 level associated with Horner's syndrome. Case report.

A case of symptomatic herniation at the first thoracic disc level is reported. The patient presented with hand weakness, Horner's syndrome, and pain radiating along the medial aspect of the upper extremity. Myelography demonstrated a smooth lateral defect at T1-2. Three sequestrated epidural disc fragments were removed with postoperatvie relief of pain. A slightly miotic pupil remains.

Adult↗
PubMedDate not supplied

Alternate day esotropia.

A six-year-old girl was noted to develop alternate day esotropia three years following surgery for a moderate "v" esotropia. Many of the usual features of cyclic esotropia, including moderate hypermetropia, mild amblyopia, moderate to large deviation, a 48-hour cyclic pattern, and a high AC/C ratio were present. A therapeutic trial with strong miotics was unsuccessful. Saccadic velocity studies revealed no evidence of lateral rectus palsy. No fluctuations in pupillary size or response, refractive errors, accommodative amplitude, visual acuity, blood pressure, behavior, and the electroencephalographic pattern were noted. Following bimedial recession surgery, the eyes have remained straight and the cyclic pattern has been abolished for a two and one half year follow-up period. There is evidence to suggest that these patients are basically strabismic with cycles of remission.

Amblyopia↗
PubMedDate not supplied

The management of esotropia with high AC/A ratio (convergence excess).

This paper reviews the long-term follow-up of esotropia with a high AC/A ratio defined as an increase of 20 delta or more of the esotropia at near compared with distance with the full optical correction of any refractive error in place. Ninety-nine patients were studied for an average follow-up of eight years. Eighty-six achieved fusion but only five achieved central fusion. Forty-five were treated with bifocals. No significant difference in the sensory results were recorded in those patients wearing bifocals compared with those who did not wear bifocals. No patient had miotic therapy for more than a few months. The suppression characteristic of this condition is reviewed.

Child, Preschool↗
PubMedDate not supplied

Congenital central hypoventilation syndrome: ocular findings in 37 children.

BACKGROUND: Congenital central hypoventilation syndrome (CCHS) is a rare cause of central sleep apnea. Although ophthalmic abnormalities have been reported, the ocular findings have not been discussed in detail. METHODS: We examined or obtained the records of 37 children with CCHS. RESULTS: Twenty-seven patients were found to have abnormal pupils, most of which were miotic and reacted poorly to light. In 18 cases, the anterior surface of the iris was unusually smooth. Ten of the children with abnormal pupils also demonstrated light-near dissociation. Twenty had strabismus of various types, and 18 showed evidence of convergence insufficiency. CONCLUSIONS: The high incidence of strabismus, pupillary abnormalities, and convergence insufficiency may be a result of neurologic defects in the midbrain.

Adolescent↗
PubMed1986

The risks of precipitating acute angle-closure glaucoma with the clinical use of mydriatic agents.

The risks of precipitating acute angle-closure glaucoma is always present when eyes have shallow anterior chambers, and early recognition of angle-closure glaucoma is important to prevent permanent loss of vision. Two groups of patients with acute angle-closure glaucoma are presented: in the first the attack was immediately preceded by the use of a mydriatic agent and in the second a mydriatic agent had been used previously without incident but the patient later presented with a spontaneous acute attack. A shallow anterior chamber, and in particular inequality of anterior chamber depths of greater than 0.2 mm, were important indicators of susceptibility to angle closure, which is more common in women than in men. Where there is a risk of angle closure, tropicamide 0.5% appears to be the safest mydriatic agent and should be followed by the administration of a miotic agent in susceptible individuals. The need to carry out a peripheral iridectomy in the other eye is stressed, irrespective of the age of the patient. A case of acute glaucoma after the use of oral drops that contained belladonna for nasal allergy further highlights the risks of the use of systemic mydriatic agents in susceptible individuals.

Acute Disease↗
PubMed1999

Acute heroin overdose.

Acute heroin overdose is a common daily experience in the urban and suburban United States and accounts for many preventable deaths. Heroin acts as a pro-drug that allows rapid and complete central nervous system absorption; this accounts for the drug's euphoric and toxic effects. The heroin overdose syndrome (sensitivity for diagnosing heroin overdose, 92%; specificity, 76%) consists of abnormal mental status, substantially decreased respiration, and miotic pupils. The response of naloxone does not improve the sensitivity of this diagnosis. Most overdoses occur at home in the company of others and are more common in the setting of other drugs. Heroin-related deaths are strongly associated with use of alcohol or other drugs. Patients with clinically significant respiratory compromise need treatment, which includes airway management and intravenous or subcutaneous naloxone. Hospital observation for several hours is necessary for recurrence of hypoventilation or other complications. About 3% to 7% of treated patients require hospital admission for pneumonia, noncardiogenic pulmonary edema, or other complications. Methadone maintenance is an effective preventive measure, and others strategies should be studied.

Drug Overdose↗
PubMed1999

[Initial clinical experience with deep sclerectomy in ambulatory surgery in glaucoma].

Deep sclerectomy is a non-perforating filtering operation used in surgical treatment of open angle glaucomas. The advantage of the operation is the creation of gradual filtration due to the thin trabecular Descement membrane which reduces markedly the risk of development of postoperative complications typical for perforating antiglaucomatous operations. The authors operated at the out-patient department 10 eyes of 8 patients (age 46-81 years). Indications for deep sclerectomy was seven times primary open angle glaucoma (POAG), once capsular glaucoma and twice normotensive glaucoma (NTG). In all eyes deep sclerectomy was indicated because of decompensation of the intraocular pressure with maximum tolerated therapy before surgery. None of the eyes were operated previously. The mean value of intraocular pressure before surgery was 25.1 +/- 6.5 mm Hg. From the results ensues that in nine operated eyes the intraocular pressure at the end of the 6-month follow-up period was compensated without supplementary therapy, only in one eye beta-blockers were prescribed one month after surgery. The cause of failure of filtration was the development of superficial adherence at the site of microperforatiion of the trabecular Descemet membrane which developed during operation. The mean intraocular pressure values at the end of the investigation period were 14.3 +/- 2.8 mm Hg. In two eyes haemorrhage into the anterior chamber was observed on the first day after surgery, the blood was absorbed within 24 hours. Hypotonia in two eyes was only transient and was not associated with a change in the depth of the anterior chamber or other complications. In none of the patients a decline of visual acuity was observed. In three operated eyes a change of refraction was necessary due to discontinuation of miotics after surgery. Deep sclerectomy is a delicate microsurgical technique which calls for experience and skill of the surgeon. The most complicated task is to prevent perforation of the trabecular Descemet membrane during surgery. Provided the surgical technique is perfect, it burdens the patient less than commonly performed perforating antiglaucomatous operations and it can be implemented in the out-patient department.

Adult↗
PubMed1999

[Squamous metaplasia of bulbar conjunctiva in the course of long-term topical antiglaucoma therapy].

PURPOSE: The aim of this study was to determine how long-term topical antiglaucoma treatment affects the bulbar conjunctiva. MATERIAL AND METHODS: 59 glaucoma patients and 30 healthy people were examined by the use of impression cytology for changes in bulbar conjunctiva. Patients with glaucoma were on stable regimen of one or two antiglaucoma drugs for a minimum 1 year. RESULTS: Squamous metaplasia of bulbar conjunctiva was found in 26.6% of patients treated with beta-blocker alone for 1-2 years and in 42.8% of patients treated with this drug for longer than 2 years. Similar changes were found in patients treated with beta-blocker with miotic--in 60% people who were on stable regimen for 1-2 years and in 70% treated longer than 2 years. No conjunctival changes were observed in healthy people. CONCLUSIONS: Long-term topical antiglaucoma medication may produce squamous metaplasia of bulbar conjunctiva.

Administration, Topical↗
PubMed1999

[Goblet cells density of bulbar conjunctiva after long-term topical antiglaucoma agents].

AIM: The purpose of this study was to determine the effect of long-term topical antiglaucoma therapy on goblet cells density of the bulbar conjunctiva. MATERIAL AND METHODS: Conjunctiva impression cytology specimens from 59 glaucoma patients and 30 healthy people were assessed quantitatively by light microscopy. Patients with glaucoma were on a stable regimen of one (beta-blocker alone) or two (beta-blocker with miotic) topically administered medications for a minimum 1-year. RESULTS: The results show statistically significant decrease in goblet cells associated with number of antiglaucoma drugs and duration of treatment. CONCLUSIONS: Long-term topical antiglaucoma treatment decrease goblet cells population of bulbar conjunctiva.

Adrenergic beta-Antagonists↗
PubMed1975

The influence of tropicamide on intraocular pressure.

Elevation of intraocular pressure by many cycloplegic drugs has been reported to occur in eyes in which the filtration angle remained open during mydriasis. Tropicamide 1% is also capable of this phenomenon in patients with open angle glaucoma who are being medicated with pilocarpine. However, in normal eyes as well as those with untreated open angle glaucoma, this cycloplegic has a relatively small effect on intraocular pressure. It is postulated that this difference between the subject groups may be due to competitive inhibition of the miotic at the receptor site in those treated with pilocarpine. In 3 patients in whom the intraocular tension elevation was found to be quite marked, heavy pigments showers in the anterior chamber occurred which suggested an outflow obstructive phenomenon similar to that seen in "Pigmentary Glaucoma."

Amides↗
PubMed1975

Fine structure and mechanics of the anterior border of the primate iris: a scanning and transmission electron microscope study.

The morphology of the anterior border of the primate iris has been examined by transmission and scanning electron microscopy. The results confirm that the anterior iris is composed of heavily pigmented melanocytes, fibroblasts, and a loosely arranged network of collagen fibres. The melanocytes are slender, elongate structures, which show some branching in the peripheral iris. They run parallel to the surface and are filled with spindle-shaped pigment granules which are oriented in the long axis of the cell. In the miotic state, the peripheral iris melanocytes form a dense, interlacing network. As the pupillary margin is approached, the angles between intersecting melanocytes diminish; the melanocytes appear to be parallel and in close contact with one another.During mydriasis, the peripheral iris melanocytes are compressed and pupillary components are found to intersect at angles greater than 90%. The superficial fibroblasts are flattened cells, closely applied to the underlying melanocyte processes and in the mydriatic iris form a resonably continous monolayer over the anterior iris surface. Iris pores are present, exposing the underlying melanocytes and stromal collagen. During miosis, the surface fibroblasts become attenuated and the pores increase in size and number. This paper demonstrates the value of the scanning electron microscope in presenting an accurate three dimensional model of the iris.

Animals↗
PubMed2001

Iatrogenic Horner's syndrome in an experimental pig.

An adult domestic female pig (Sus scrofa) exhibited clinical signs of right-sided Horner's syndrome after experimental placement of a woven aortic stent followed by aortic catheterization. The clinical signs included a miotic pupil, ptosis of the upper eyelid, prolapse of the nictitating membrane, and enophthalmos. Necropsy revealed a large mass in the right midcervical region that encased or was in contact with the carotid artery, internal jugular vein, and vagus nerve. Closer evaluation of the mass revealed that it was a small piece of surgical suture material that was embedded within the lumen of the carotid artery. This extrinsic material served as a nidus for an inflammatory reaction involving the vagus nerve.

Animals↗
PubMed2001

[A case of carbamate poisoning in which GCMS was useful to identify causal substance and to decide the appropriate treatment].

We often have cases of insecticide poisoning where the patient is unconscious and the causal substances are unknown. We report an 83-year-old unconscious man who had apparently ingested several agricultural chemicals, possibly organophosphate or carbamate. According to his family, there were three kinds of containers of agricultural chemicals with their caps opened around him. When he was transferred to our hospital, he presented hypertension, hypersalivation, and muscle fasciculation. His pupils were markedly miotic. In order to identify the substances ingested we used a gas chromatographymass spectrometer (GCMS) using his gastric content. Within 30 minutes we were able to identify the causal substance as methomyl, one of the popular carbamates, thereby eliminating the need to use pralidoxime (PAM). GCMS makes it possible to identify unknown substances quickly and accurately and is therefore extremely useful in deciding the appropriate treatment.

Aged↗
PubMed1975

Macular hole following topical pilocarpine.

A unique case of macular hole following the instillation of pilocarpine is presented. Miotically induced vitreoretinal traction was postulated as the mechanism for hole formation.

Administration, Topical↗
PubMed2001

[Difficulties in cataract surgery of patient with old glaucoma].

Cataract surgery of glaucoma patients treated with Pilocarpine several years, with a small and miotic pupil, with synechiae is an important problem of management. The self-retaining flexible iris retractor is a microsurgical innovation that allows adequate enlargement of the pupil without iris incision. Each retractor is inserted through a separate self-sealing beveled incision made as far posteriorly in the cornea as possible. The retractors are spaced 90 degree apart and can easily be removed following implant insertion. The conclusion is that if we obtain an adequate enlargement of the pupil we can choose any cataract surgery technique, even phacoemulsification or EEC.

Cataract↗