The pilocarpine paradox.
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Glaucoma, Angle-Closure↗
Biomedical subjects
R Ritch
Publications and source records attributed to R Ritch.
Ultrasound biomicroscopy of the anterior segment.
BACKGROUND: New imaging technologies are revolutionizing the understanding and treatment of a wide variety of ocular disorders. Confocal scanning laser ophthalmoscopy, ultrasound biomicroscopy, confocal scanning laser polarimetry, color doppler imaging of blood flow, and optical coherence tomography are providing important information regarding disease pathophysiology, diagnosis, progression, and treatment. METHODS: High frequency (50 MHz), high resolution ultrasound biomicroscopy of the anterior segment was obtained in a wide variety of disorders of the anterior segment. Tissue resolution is approximately 50 microns and the penetration depth is 5 mm. RESULTS: Ultrasound biomicroscopy is capable of imaging the comea, iris, anterior chamber, anterior chamber angle, posterior chamber, and ciliary body with great detail. The structures surrounding the posterior chamber, previously hidden from clinical observation, can be imaged and their normal anatomic relationships assessed. The various forms of angle closure glaucoma, such as pupillary block and plateau iris configuration, can be differentiated. The concave iris found in pigment dispersion and its response to treatment can be assessed. Visualization of anterior segment anatomy in eyes with opaque media is possible. CONCLUSIONS: Ultrasound biomicroscopy assists in the management of eyes with disorders of the anterior segment. Future applications of this technology will yield important information regarding accommodation, normal ocular physiology and disease pathophysiology.
Anterior Eye Segment↗
A unification hypothesis of pigment dispersion syndrome.
PURPOSE: To synthesize recent findings regarding pigment dispersion syndrome in order to arrive at a hypothesis concerning the nature of an underlying genetic predisposition. METHODS: The literature on the subject was reviewed and analyzed. RESULTS: Eyes with pigment dispersion syndrome differ from normal in that they have a larger iris, a midperipheral posterior iris concavity that increases with accommodation, a more posterior iris insertion, increased iridolenticular contact that is reversed by inhibition of blinking, possibly an inherent weakness of the iris pigment epithelium, and an increased incidence of lattice degeneration of the retina. CONCLUSION: A gene affecting some aspect of the development of the middle third of the eye early in the third trimester appears at the present time to be the most likely cause.
Animals↗
The efficacy of apraclonidine as an adjunct to timolol therapy. Apraclonidine Adjunctive Therapy Study Group.
OBJECTIVE: To compare the intraocular pressure (IOP) lowering efficacy of 0.5% and 1.0% apraclonidine hydrochloride when used adjunctively with 0.5% timolol maleate in 129 patients. DESIGN: A multicenter, randomized, double-masked clinical trial. Adult patients of either sex diagnosed as having either open-angle glaucoma or ocular hypertension were enrolled in the study. Patients using only 0.5% timolol maleate twice daily for at least 4 weeks and who had 8 AM IOPs of at least 22 mm Hg and no greater than 30 mm Hg 12 hours after dosing were eligible for the study. After 8 AM baseline IOPs were obtained while patients were taking timolol only, they were then randomized to receive either 0.5% or 1.0% apraclonidine twice daily in addition to their timolol. Intraocular pressures were measured at 8 AM (before morning dosing) and at 11 AM (3 hours after dosing) on days 14 and 90 and at 8 AM only on day 45. RESULTS: Both concentrations of apraclonidine produced significant IOP reductions from baseline at all visits (P < .001). At 8 AM, after the nighttime dose, the additional mean IOP reduction from the timolol baseline ranged from 2.5 to 3.3 mm Hg (10.3% to 13.6% reduction, respectively). At 11 AM, 3 hours after the morning dose, the additional IOP reduction from the timolol baseline ranged from 4.7 to 5.2 mm Hg (20.0% to 21.7%, respectively). No difference in IOP reduction was observed between the 0.5% and 1.0% apraclonidine concentrations and no loss of IOP efficacy was observed for either concentration for the duration of the study. Sensitivity to 0.5% and 1.0% apraclonidine was observed in nine (13.8%) and 13 (20.3%) patients, respectively. Overall, therapy was discontinued owing to ocular or nonocular side effects with 0.5% and 1.0% apraclonidine in 14 (21.5%) and 16 (25%) patients, respectively. CONCLUSIONS: We believe that 0.5% apraclonidine is equally effective as 1.0% apraclonidine when used twice daily as the first adjunctive drug to timolol. The drug effect is maintained for at least 90 days.
Adrenergic alpha-Agonists↗
Epithelial inclusion cyst of the iris.
We describe the clinical presentation, high-frequency ultrasound biomicroscopic characteristics, and pathologic findings associated with a conjunctival inclusion cyst within the iris. The patient had undergone an uncomplicated extracapsular cataract extraction with posterior chamber intraocular lens insertion 9 months prior to presenting with a progressively enlarging iris mass. A clinical examination revealed a solid-appearing white tumor within the midiris stroma, accompanied by limbal-conjunctival hyperemia and anterior chamber inflammation. Ultrasound biomicroscopy revealed an egg-shaped solid iris stromal tumor that displaced the pigment epithelium. The mass was composed of three concentric layers of different echogenicity: a moderately reflective mantle, a less reflective middle zone, and a hyperreflective core. Within 3 days of initiation of topical corticosteroid therapy (prednisolone acetate, 0.5 mg per drop four times daily), the tumor enlarged and induced a plasmoid aqueous and a hypopyon. Histopathologic study revealed a conjunctival inclusion cyst with evidence of acute and chronic inflammation. We have found that the diagnosis of epithelial inclusion cyst within the iris can be aided by an ultrasound evaluation. This case also suggests that it may be preferable to excise these tumors prior to topical corticosteroid treatment.
Aged↗
Ultrasound biomicroscopy in the management of malignant melanoma of the iris.
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Aged↗
Short-term efficacy of apraclonidine hydrochloride added to maximum-tolerated medical therapy for glaucoma. Apraclonidine Maximum-Tolerated Medical Therapy Study Group.
PURPOSE: We determined whether the addition of topical apraclonidine hydrochloride to eyes that are receiving maximal medical therapy but still have inadequate intraocular pressure control and that are scheduled to undergo surgery could adequately decrease intraocular pressure, postponing the need for further intervention. METHODS: We performed a prospective, 90-day, multicentered, placebo-controlled, double-masked parallel study. We enrolled one eye each of 174 glaucoma patients with inadequate intraocular pressure control who were on maximally tolerated medical therapy. We continued to administer maximum medical therapy for glaucoma. Study medications were either apraclonidine hydrochloride 0.5% or placebo (apraclonidine's vehicle). Patients were instructed to take the study medication every eight hours. We measured intraocular pressure, change in intraocular pressure from baseline, and the number of eyes requiring surgery after the addition of study medication. RESULTS: Fifty-two (60%) of 86 patients treated with apraclonidine maintained adequate intraocular pressure control throughout the study and avoided surgery, compared with 28 (32%) of 88 patients treated with placebo (P < .001). Apraclonidine treatment resulted in significantly more patients attaining an additional 20% reduction or more in intraocular pressure from baseline and an intraocular pressure less than or equal to 20 mm Hg (P < .05). The most common ocular complication was conjunctival hyperemia (11 of 86 patients, 12.8%). The most frequent nonocular problem was dry mouth (four patients, 4.7%). CONCLUSION: Apraclonidine appeared to be safe in all eyes and efficacious in some eyes. It significantly lowered intraocular pressure when used in combination with maximally tolerated medical therapy, which delayed or prevented further glaucoma surgery for at least 90 days in 52 (60%) of 86 treated patients.
Adrenergic alpha-Agonists↗
Prevent Blindness America visual field screening study. The Prevent Blindness America Glaucoma Advisory Committee.
PURPOSE: To assess the screening efficacy and practical use of two portable devices to detect moderate to severe visual field loss rapidly in population screening. METHODS: Henson visual field analysis and Damato campimetry for glaucoma were performed in a healthy adult population, to determine false-positive rates; in established glaucoma patients and suspects, to determine false-negative rates; and in a general adult population, to assess practical use in actual screenings. RESULTS: There were no false-positive test failures among the 82 normal subjects who completed the Henson two-step screening. Eighty of 83 normal subjects passed Damato campimetry, resulting in a false-positive rate of 3.6%. Among 83 glaucoma suspects and patients, the Henson test identified 49 (84%) of 58 subjects whose full-threshold fields from Humphrey perimetry were abnormal, 38 (97%) of 39 of whom had moderate to severe visual field loss. The Damato campimeter detected 55 (81%) of 68 subjects with any pathologic loss on full-threshold visual fields, 44 (92%) of 48 of whom had moderate to severe visual field loss. Among 1,278 subjects tested in general population screenings, 55 subjects (4.3%) failed either or both tests. CONCLUSIONS: The Henson visual field analyzer can discriminate moderately to severely diseased from normal visual fields with high sensitivity and specificity. The Damato campimeter can reliably detect moderate to severe visual field loss with a tolerably low false-positive rate. To overcome the weakness of glaucoma screening by tonometry alone, some forms of visual field testing may be acceptably brief (cost effective) and accurate (sensitive and specific).
Adolescent↗
Prevention of blinking alters iris configuration in pigment dispersion syndrome and in normal eyes.
PURPOSE: To examine the effect of blinking on iris configuration and aqueous humor distribution between the posterior and anterior chambers in eyes with pigment dispersion syndrome compared with healthy eyes. METHODS: High-resolution, anterior segment ultrasound biomicroscopy was performed on ten eyes of ten patients with untreated pigment dispersion syndrome and on ten control subjects. Patients were scanned continuously for 15 minutes or until the maximal change in iris configuration occurred. During this time, the eyelids were held open mechanically, and blinking was prevented. Eyes then were rescanned immediately after blinking. RESULTS: Initial iris configuration was concave in all eyes with pigment dispersion syndrome, whereas in control eyes it was concave in four eyes, planar in four eyes, and convex in two eyes. Iridozonular contact occurred in eyes with pigment dispersion syndrome only. Iridolenticular contact was greater in eyes with pigment dispersion syndrome than in control eyes. Analysis of covariance controlling for age, sex, and refractive error showed pigment dispersion syndrome to be a significant predictor of increased iris concavity. During continuous scanning, the mean change in iris position, from most concave to most convex, and mean time to the maximal change in iris configuration were greater for eyes with pigment dispersion syndrome than in control eyes and were related to the degree of initial iris concavity only (analysis of covariance). In six eyes with pigment dispersion syndrome, the eye cup was removed, normal blinking was permitted, and the eye was rescanned. The iris resumed a concave configuration in all eyes. CONCLUSION: Increased iris concavity in pigment dispersion syndrome appears to be related to increased iridolenticular contact. This creates an anatomic configuration that predisposes to reverse pupillary block. The accumulation of aqueous humor in the posterior chamber, when blinking is prevented, alters iris position in pigment dispersion syndrome and in healthy eyes and increases iridozonular and iridociliary-process distances while minimizing iridolenticular contact. Normal blinking appears to create transient vector forces which promote aqueous humor flow from the posterior to anterior chamber.
Adult↗
Topical apraclonidine hydrochloride in eyes with poorly controlled glaucoma. The Apraclonidine Maximum Tolerated Medical Therapy Study Group.
OBJECT: We determined whether the addition of topical apraclonidine hydrochloride to eyes receiving maximal medical therapy, with inadequate intraocular pressure (IOP) control, and scheduled to undergo surgery, could adequately lower IOP, postponing the need for surgical intervention. DESIGN: A prospective 90 day, multi-centered, placebo-controlled, doublemasked parallel study. PATIENTS: We enrolled 174 glaucoma patients with inadequate IOP control on maximally tolerated medical therapy. All were candidates for either laser trabeculoplasty or invasive surgical intervention. We enrolled only one eye per patient. INTERVENTIONS: We continued to administer maximum-tolerated medical therapy for glaucoma. Patients took the study medication every eight hours. Study medications were either apraclonidine hydrochloride 0.5% or placebo (apraclonidine's vehicle). MAJOR OUTCOME MEASURES: We evaluated IOP, IOP change from baseline, and the number of eyes requiring surgery after the addition of study medication. RESULTS: Sixty one percent of patients treated with apraclonidine maintained adequate IOP control throughout the study, avoiding additional surgery compared to 33.9% patients treated with placebo (P < .001). Apraclonidine treatment resulted in significantly more patients achieving either an additional > or = 20% reduction in IOP from baseline (resulting in an IOP < or = 20 mm Hg) (P < 0.05). The most common ocular complications were conjunctival hyperemia (12.6%), itching and foreign body sensation (6.8%), and tearing (4.5%). The most frequent non-ocular adverse events related to apraclonidine were dry mouth (4.5%) and unusual taste perception (2.2%). CONCLUSIONS: Apraclonidine appears safe and efficacious. It significantly lowered IOP when used in combination with a patient's maximum tolerated medical therapy. This delayed or prevented further glaucoma surgery for at least 90 days in approximately 60% of treated patients.
Administration, Topical↗
Parental history and myopia: taking the long view.
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Child↗
5-Fluorouracil after primary combined filtration surgery.
We examined the safety and efficacy of 5-fluorouracil in eyes with open-angle glaucoma undergoing combined cataract removal and filtration surgery. We randomly assigned one eye each of 24 patients to receive 5-fluorouracil (five injections of 5 mg during two weeks after surgery) and one eye each of 20 patients to comprise the control group. Preoperatively, the two groups had similar mean intraocular pressure (P = .8) and number of medications (P = .2). The mean intraocular pressure of the 5-fluorouracil group was 18.6 +/- 1.1 mm Hg, with 2.5 +/- 0.3 medications; that of the control group was 18.2 +/- 1.2 mm Hg, with 2.2 +/- 0.2 medications. One year postoperatively, intraocular pressure and the number of medications were significantly reduced by a similar amount in both groups of patients (5-fluorouracil, 14.2 +/- 0.7 mm Hg, 0.8 +/- 0.2 medications; controls, 14.3 +/- 0.6 mm Hg, 1.0 +/- 0.2 medications). Transient superficial punctate keratopathy occurred more frequently (P = .04) in the 5-fluorouracil group (16 of 24 eyes, 67%) than in the control group (seven of 20 eyes, 35%). In our randomized and prospective study, the adjunctive use of 5-fluorouracil did not result in improved control of intraocular pressure one year after combined surgery in eyes with open-angle glaucoma.
Aged↗
Oral imipramine and acute angle closure glaucoma.
OBJECTIVE: To document acute angle closure glaucoma temporally related to ingestion of oral imipramine hydrochloride. PATIENTS: Four patients with narrow angles received routinely prescribed doses of imipramine that triggered acute angle closure glaucoma. OUTCOME: Laser iridotomy was successful in all patients. CONCLUSIONS: Psychoactive drugs should be prescribed cautiously in patients with known narrow angles and should be monitored by an ophthalmologist.
Acute Disease↗
Initial argon laser trabeculoplasty to the inferior vs superior half of trabecular meshwork.
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Exfoliation Syndrome↗
Treatment of bleb infection after glaucoma surgery.
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Anti-Bacterial Agents↗