Pilocarpine induces an increase in the anterior chamber angular width in eyes with narrow angles

Kobayashi, Hiroshi; Kobayashi, Kaori; Kiryu, Junichii; Kondo, Takehisa

doi:10.1136/bjo.83.5.553

Cited by 28 publications

(23 citation statements)

References 22 publications

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“…It has been found that angle opening is increased after pilocarpine installation in eyes with narrow angle whereas angle opening is decreased in eyes with a wider or normal angle. 66 Over the past few years the rat has gained prominence as an animal model for the study of glaucoma. Nissirios N et al 67 investigated the normal rat anterior segment anatomy in vivo using ultrasound biomicroscopy (UBM) and determined the effect of both cholinergic and anticholinergic medications on angle structures.…”

Section: Effects Of Drugsmentioning

confidence: 99%

Ultrasound Biomicroscopy in Glaucoma: An Update

Dada¹,

Gaurav²,

Mishra³

2008

JOCGP

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UBM is a high-frequency ultrasound technology that provides exceptionally detailed two-dimensional gray-scale images of the various anterior segment structures and evaluates them both quantitatively and qualitatively. It allows noninvasive in vivo imaging of structural details of the anterior ocular segment at near microscopic resolution and thus, there are many other applications of this new imaging method.This review outlines the uses of UBM in diagnosis and management of glaucoma.

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Section: Effects Of Drugsmentioning

confidence: 99%

Ultrasound Biomicroscopy in Glaucoma: An Update

Dada¹,

Gaurav²,

Mishra³

2008

JOCGP

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“…In the latter case, parasympathomimetics may aggravate the pupillary block not only by enlarging the lens-iris surface contact area (lens-iris apposition), but also by increasing the axial lens thickness and causing anterior lens movement, thus shallowing further the anterior chamber (Ritch and Liebmann 1996). It should be noted that parasympathomimetics increase the angle width in patients with narrow angles (Kobayashi et al 1999) but they may paradoxically shallow the anterior chamber and increase the pupillary block (Hung et al 1995). Because these drugs may increase the pupillary block by causing forward motion of the lens-iris diaphragm, they are contraindicated in conditions where the glaucoma is caused by anterior displacement of the iris-lens diaphragm.…”

Section: Clinical Usementioning

confidence: 99%

“…This is the effect that shapes the efficacy of pilocarpine (as well as other parasympathomimetics) in therapy of patients with angle closure glaucoma, because in these cases the drug can widen or open the drainage angle, thus improving or enabling the access of AH to the trabecular and uveoscleral outflow pathways (Kobayashi et al 1999). …”

Section: Mechanism Of Actionmentioning

confidence: 99%

Autonomic drugs in the treatment of canine and feline glaucoma – Part I: Medications that lower intraocular pressure by increasing the outflow of aqueous humour

Maślanka¹

2014

Polish Journal of Veterinary Sciences

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One characteristic of the most common types of glaucoma is increased intraocular pressure (IOP), which has a damaging effect on optic nerve axons, leading to progressive loss of retinal ganglion cells. Therefore, ocular hypotensive drugs are the mainstay of pharmacological therapy for glaucoma. This review article, which is the first part of a two-part series, is dedicated to autonomic drugs which lower IOP by increasing the outflow of aqueous humour. These agents are subdivided into two groups: (a) drugs that lower IOP by increasing the trabecular outflow and the uveoscleral outflow (i.e. nonselective adrenergic agonists), and (b) medications that lower IOP by opening of the drainage angle and by increasing the conventional outflow via the trabecular outflow (i.e. parasympathomimetics). This paper summarizes the current state of knowledge on the mechanism of action of these drugs and their effect on IOP in dogs and cats. Moreover, it discusses possible undesirable side effects of these medications and presents the current ideas about their role and position in the medical management of glaucoma in small animals.

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“…Kobayashi et al [30] found that the angle opening increased after the instillation of pilocarpine in eyes with narrow angles but decreased in eyes with a wider or normal angle. Marchini et al [31] reported that the potent mydriatic effect of 2% ibopamine was greater than that of 10% phenylephrine or 1% tropicamide.…”

Section: Clinical Application Of Quantitative Ultrasound Biomicroscopmentioning

confidence: 99%

Anterior segment imaging: ultrasound biomicroscopy

Ishikawa¹,

Schuman²

2004

Ophthalmology Clinics of North America

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High-frequency ultrasound biomicroscopy (UBM) (Paradigm Medical Industries, Salt Lake City, Utah) provides high-resolution in vivo imaging of the anterior segment in a noninvasive fashion. In addition to the tissues easily seen using conventional methods (ie, slit lamp), such as the cornea, iris, and sclera, structures including the ciliary body and zonules, previously hidden from clinical observation, can be imaged and their morphology assessed. Pathophysiologic changes involving anterior segment architecture can be evaluated qualitatively and quantitatively. This article discusses the role of UBM in imaging of the anterior segment of the eye from the qualitative and quantitative analysis point of view. Equipment and techniqueThe technology for UBM, originally developed by Pavlin, Sherar, and Foster, is based on 50-to 100-MHz transducers incorporated into a B-mode clinical scanner [1][2][3]. Higher frequency transducers provide finer resolution of more superficial structures, whereas lower frequency transducers provide greater depth of penetration with less resolution. The commercially available units operate at 50 MHz and provide lateral and axial physical resolutions of approximately 50 μm and 25 μm, respectively. Tissue penetration is approximately 4 to 5 mm. The scanner produces a 5 × 5 mm field with 256 vertical image lines (or A-scans) at a scan rate of 8 frames per second.Each A-scan is mapped into oversampled 1024 points, with 256 gray-scale levels representing the logged amplitude of reflection, and then the number of points is downsized to 432 pixels to fit on the UBM monitor. The real-time image is displayed on a video monitor and can be recorded on videotape for later analysis. Room illumination, fixation, and accommodative effort affect anterior segment anatomy and should be held constant, particularly when quantitative information is being gathered.The image acquisition technique has been described elsewhere and is similar to traditional immersion B-scan ultrasonography [3][4][5]. In the Paradigm Instruments UBM, the probe is suspended from a gantry arm to minimize motion artifacts, and lateral distortion is minimized by a linear scan format. In the OTI (Ophthalmic Technologies, Toronto, Canada) device, the probe is small and light enough not to require a suspension arm, and a sector scanning method is used. Scanning is performed with the patient in the supine position. A plastic eyecup of the appropriate size is inserted between the lids, holding methylcellulose or normal saline coupling medium. To maximize the detection of the reflected signal, the transducer should be oriented so that the scanning ultrasound beam strikes the target surface perpendicularly. In the normal eye, the cornea, anterior chamber, posterior chamber, iris, ciliary body, and anterior lens surface can be recognized easily (Fig. 1). The scleral spur is the only constant landmark allowing one to interpret UBM images in terms of the morphologic status of the anterior chamber angle and is the key for analyzing angle pathology. ...

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Pilocarpine induces an increase in the anterior chamber angular width in eyes with narrow angles

Cited by 28 publications

References 22 publications

Ultrasound Biomicroscopy in Glaucoma: An Update

Ultrasound Biomicroscopy in Glaucoma: An Update

Autonomic drugs in the treatment of canine and feline glaucoma – Part I: Medications that lower intraocular pressure by increasing the outflow of aqueous humour

Anterior segment imaging: ultrasound biomicroscopy

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