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Biomedical subjects

A L Robin

Publications and source records attributed to A L Robin.

At least 73 records · Page 4Linked to original sources
PubMed1989

A path analysis of an adolescent drinking behavior model derived from problem behavior theory.

The interrelationships between composite variables comprised of demographics, socialization, personality, perceived environment, conventional and problem behaviors, and their combined mediational influences on adolescent drinking behavior are examined. Students randomly sampled from four suburban, metropolitan-area high schools (N = 499) were administered the 250-question Survey of Underage Drinking Styles. All 12 composite variables, derived from the survey, were arranged in a causal model and submitted to a confirmatory path analysis. Data were analyzed by multiple regression procedures. According to the present model, a powerful pathway through to drinking may begin with family interaction problems, which may lead to a reduction in the adolescent's social coping skills. A reduction in the adolescent's coping skills may lead to a compensatory belief that alcohol improves mental and physical functions and an increased affiliation with and acceptance of the peer group's attitude and behavior toward consuming alcohol as a replacement coping skill. The adolescent's drinking may then increase as a result of the affiliative need to conform to peer group pressure.

Adolescent↗
PubMed1989

"Outlier" intraocular pressure readings: valid or invalid for statistical analysis?

Wide variations in the response to intraocular (IOP)-lowering medications may be due to the normal response of the subjects or to variables unrelated to the effect of medication, eg, noncompliance or recording errors. We used data from a previous study of medications designed to lower IOP to investigate the influence of readings showing an unusually large increase in IOP from baseline on the statistical analysis and conclusions. These readings, which could have been due to variables unrelated to the effect of medication, were defined as "outliers" by a statistical method. A statistically insignificant difference between two IOP-lowering medications became significant on excluding two subjects with outlier IOP readings. We explain how reporting results obtained with and without including outliers in the analysis may provide clinicians with more complete information.

Analysis of Variance↗
PubMed1988

Increased intraocular pressure in the immediate postoperative period after extracapsular cataract extraction.

We evaluated the immediate intraocular pressure increase after extracapsular cataract surgery in 58 eyes. Two to three hours postoperatively, 34 eyes (59%) developed an intraocular pressure greater than or equal to 25 mm Hg. We found an intraocular pressure of at least 40 mm Hg in seven eyes. Mean intraocular pressure two to three hours postoperatively was 8.9 +/- 9.8 mm Hg greater than the preoperative intraocular pressure. The use of intraocular sodium hyaluronate had no apparent effect on intraocular pressure.

Aged↗
PubMed1988

Prevention of the rise in intraocular pressure following neodymium-YAG posterior capsulotomy using topical 1% apraclonidine.

We studied apraclonidine hydrochloride (aplonidine hydrochloride or ALO 2145), an alpha-agonist, for its effect on the intraocular pressure (IOP) rise following neodymium-YAG posterior capsulotomy (YPC). In a prospective multicentered double-masked study, 63 eyes were pretreated with one drop of either 1% apraclonidine hydrochloride or placebo one hour before performing YPC and again following the laser treatment. The greatest IOP rise in the placebo-treated eyes occurred in the third hour after YPC, when the mean (+/- SD) IOP rose from a baseline pressure of 16.4 +/- 3.7 to 20.8 +/- 6.8 mm Hg. In apraclonidine-treated eyes, the IOP fell from a mean of 15.6 +/- 3.8 to 12.8 +/- 6.0 mm Hg three hours postoperatively. There were five times as many eyes that had an IOP rise greater than 10 mm Hg in the placebo-treated group compared with those treated with apraclonidine. Apraclonidine proved to be highly effective in preventing the rise in IOP following YPC.

Administration, Topical↗
PubMed1988

A combination of levobunolol and dipivefrin for the treatment of glaucoma.

This double-masked prospective study compared the ocular hypotensive efficacy and the safety of 0.5% and 1% levobunolol hydrochloride with 0.5% timolol maleate when each was administered topically twice daily in combination with 0.1% dipivefrin hydrochloride. Forty-three patients whose intraocular pressure was previously controlled by concomitant treatment with timolol and dipivefrin were randomly assigned to receive 0.5% or 1% levobunolol and 0.1% dipivefrin, or to continue to receive 0.5% timolol and 0.1% dipivefrin for three months. In the groups receiving levobunolol and dipivefrin concurrently, continued intraocular pressure control was achieved equal to that attained with timolol and dipivefrin before study entry. We concluded that concomitant treatment with levobunolol and dipivefrin is equal in both efficacy and safety to concomitant treatment with timolol and dipivefrin.

Drug Combinations↗
PubMed1988

Short-term effects of unilateral 1% apraclonidine therapy.

A prospective, double-masked, randomized study evaluated the effects of unilateral therapy with topical 1% apraclonidine hydrochloride (aplonidine hydrochloride or ALO 2145) in 20 normal volunteers. No medications were applied to either eye during the control day. Following baseline measurements on the day of treatment, one drop of topical 1% apraclonidine hydrochloride was placed on one eye and a placebo (vehicle) was placed on the fellow eye. Intraocular pressure (IOP) measurements, pupil size, blood pressure, and pulse rate were assessed on both days at the baseline and 1, 3, 5, and 7 hours later. The 1% apraclonidine hydrochloride lowered the mean IOP (+/- SD) a maximum of 6.5 +/- 4.3 mm Hg (37.3% +/- 20.4%) from the baseline on the day of treatment. A statistically significant 2.7 +/- 3.4-mm Hg (14.9% +/- 19.0%) mean IOP decrease from the baseline was noted in the contralateral placebo-treated eye. No significant changes in the coefficient of outflow, blood pressure, or heart rate were noted. Eyelid retraction, conjunctival blanching, and mydriasis were frequently noted in eyes treated with 1% apraclonidine hydrochloride.

Administration, Topical↗
PubMed1988

Apraclonidine. A one-week dose-response study.

We performed a double-masked, cross-over, dose-response study of apraclonidine hydrochloride (formerly known as ALO 2145) in 20 patients with elevated intraocular pressure (IOP). We administered three concentrations of apraclonidine (0.125%, 0.25%, 0.5%) and vehicle alone bilaterally every 12 hours for one week. Patients were examined 2, 5, and 8 hours after the initial dose, and then on day 2 and day 8. We studied IOP, pupillary diameter, interpalpebral fissure width, blood pressure, and pulse. There was a two-week washout period after each one-week session. All concentrations of apraclonidine significantly lowered IOP. The 0.5% and 0.25% concentrations had equal maximal effects, lowering IOP in each patient by an average of 27% relative to vehicle alone. This corresponded to a mean decrease in IOP of 8.7 mm Hg, from a baseline of 24.9 mm Hg to 16.2 mm Hg. The 0.5% and 0.25% concentrations were significantly more effective than the 0.125% concentration at two and eight hours. Mean interpalpebral fissure width increased in a dose-dependent fashion; the pupillary effect was minimal. Blood pressure and pulse were unchanged. Thirty percent of subjects reported transient dry nose or dry mouth. These symptoms may be dose-dependent.

Administration, Topical↗
PubMed1988

Neodymium: YAG and argon laser iridotomy. Long-term follow-up in a prospective, randomized clinical trial.

Neodymium:YAG (Nd:YAG) and argon laser iridotomies were compared in a prospective, randomized clinical trial of 43 patients with bilateral chronic pupillary-block glaucoma. All patients had one eye randomly assigned to argon and the fellow eye assigned to Nd:YAG laser treatment. Follow-up ranged from 20 to 42 months. Iridotomy closure was not observed in Nd:YAG-treated eyes, but nine (21%) argon iridotomies required retreatment. Visual loss due to progression of laser-induced lens or corneal damage was not observed in any eye. Nine (21%) argon-treated eyes and eight (19%) Nd:YAG-treated eyes required laser trabeculoplasty for further intraocular pressure (IOP) lowering after iridotomy. Five (12%) argon-treated and two (5%) Nd:YAG-treated eyes required intraocular filtration surgery for long-term IOP control, but this difference was not statistically significant. There were no significant long-term differences between these treatment modalities.

Adult↗
PubMed1988

Long-term follow-up of neodymium: YAG laser angle surgery for open-angle glaucoma.

Seventy-nine eyes (61 patients) with open-angle glaucoma and uncontrolled intraocular pressure (IOP) of 23 mmHg or more despite maximal tolerated medical therapy and prior argon laser trabeculoplasty (75 eyes) were treated with neodymium: YAG (Nd: YAG) laser angle surgery and followed for at least 1 year. Ten pulses of 10 mJ were applied to the midtrabecular meshwork over 40 degrees in the most visible portion of the angle. The IOP was controlled successfully (less than or equal to 22 mmHg) in 60 eyes (76%) 1 month after treatment and in 36 of 78 eyes (46%) 1 year after treatment. Long-term complications included two eyes with advanced glaucoma that lost central fixation despite good IOP control after treatment.

Aluminum Silicates↗
PubMed1988

Effectiveness of apraclonidine in preventing the rise in intraocular pressure after neodymium:YAG posterior capsulotomy.

Apraclonidine (para-aminoclonidine) is an alpha agonist that was studied for its effect on the IOP rise following YPC. In a prospective multicentered double-masked study 63 eyes were pretreated with one drop of either 1% apraclonidine or placebo 1 hour prior to performing YAG and again after the laser treatment. The greatest IOP rise in the placebo-treated eyes occurred in the third hour after YPC when the mean IOP rose from a baseline pressure of 16.4 +/- 3.7 mm Hg to 20.8 +/- 6.8 mm Hg (P less than .01). In apraclonidine-treated eyes the IOP fell from a mean of 15.6 +/- 3.8 mm Hg to 12.8 +/- 6.0 mm Hg 3 hours postoperatively (P less than .001). There were five times as many eyes that had a pressure rise greater than 10 mm Hg in the placebo-treated group compared to those treated with apraclonidine. Apraclonidine proved to be highly effective in preventing the rise in IOP following YPC.

Administration, Topical↗
PubMed1987

Hypotony and choroidal detachment as late complications of trabeculectomy.

Seven eyes of six patients with glaucoma developed a flat anterior chamber, hypotony, and choroidal detachment two to 26 months after technically uncomplicated trabeculectomy. No signs warranting immediate surgical intervention, such as wound or bleb leakage, contact between cornea and lens, or massive choroidal detachments touching in the midvitreous cavity were found on initial examination. After treatment with topical corticosteroids and cycloplegic eyedrops, five of seven eyes showed marked clinical improvement within one month. The two remaining eyes eventually returned to normal anterior chamber depth, but required repeat filtration surgery for intraocular pressure control.

Administration, Topical↗
PubMed1987

Effects of ALO 2145 on intraocular pressure following argon laser trabeculoplasty.

A prospective, randomized, double-masked study compared topical 1% ALO 2145, an alpha 2-agonist, with placebo in therapy for immediate postoperative intraocular pressure (IOP) rise after argon laser trabeculoplasty. Seventy-three eyes (73 patients) underwent 360 degrees of treatment utilizing 80 spots of 800 to 1000 mW of power. Intraocular pressure rise was measured hourly for the first three hours after operation, at one week, and at one month. Eyes treated with ALO 2145 had both significantly lower mean IOPs and greater IOP decreases from baseline than placebo-treated eyes during the first three hours after operation. No eyes treated with ALO 2145 and six eyes (18%) treated with placebo experienced an IOP rise of 10 mm Hg or greater. Twenty eyes (59%) in the placebo group and eight eyes (21%) treated with ALO 2145 had an IOP elevation. No change was detected in the mean heart rate. ALO 2145 appears to be effective in eliminating large, acute IOP elevations after argon laser trabeculoplasty.

Adrenergic alpha-Agonists↗
PubMed1987

The safety and efficacy of topical 1% ALO 2145 (p-aminoclonidine hydrochloride) in normal volunteers.

We prospectively evaluated the efficacy and safety of the twice-daily application of 1% ALO 2145 (p-aminoclonidine hydrochloride, a topical alpha 2-agonist) in 21 normal volunteers for one month. Criteria measured included intraocular pressure (IOP), basal tear secretion, pupillary size, corneal sensitivity, heart rate, and blood pressure; urinalysis and blood chemistry studies were also performed. The mean (+/- SD) IOP fell 38.7%, from 17.5 +/- 3.9 mm Hg to 10.7 +/- 3.4 mm Hg, in five hours. The mean IOP remained between 23% and 30% below the pretreatment level when checked 12 hours after the last drop's instillation from day 8 through day 28 of the study. No clinically significant changes in mean systolic blood pressure, blood chemistry values, urinalysis results, basal tear secretion, or corneal sensitivity were noted. The mean heart rate and diastolic blood pressure were each significantly decreased at only one of nine time intervals. Dry mouth was noted at some time in 52% of volunteers. ALO 2145 seems to be effective in lowering IOP in normal volunteers, without marked cardiovascular effects.

Adult↗
PubMed1987

Effects of topical ALO 2145 (p-aminoclonidine hydrochloride) on the acute intraocular pressure rise after argon laser iridotomy.

A prospective, randomized, double-masked pilot study compared topical 1% ALO 2145 (p-aminoclonidine hydrochloride, a topical alpha 2-agonist) with a placebo to determine its ability to minimize any acute postoperative intraocular pressure (IOP) increase after argon laser iridotomy. Twenty-eight eyes (21 patients) with chronic narrow angle glaucoma underwent argon laser iridotomy. Fourteen eyes were treated with ALO 2145; the remainder received a placebo. All eyes received one drop of the appropriate medication one hour before and following the iridotomy. Six eyes (43%) treated with the placebo and no eyes treated with ALO 2145 experienced an IOP increase greater than 10 mm Hg over baseline. The mean IOPs and mean IOP changes from baseline were significantly lower during the first three postoperative hours in the eyes treated with ALO 2145. No significant difference was noted in the ease of iridotomy formation, rate of iridotomy closure, visual acuity, anterior segment inflammation, or mean heart rate.

Argon↗
PubMed1986

Q-switched neodymium-YAG laser iridotomy. A field trial with a portable laser system.

The efficacy of a small, portable, battery-operated, Q-switched neodymium-YAG laser with a slit-lamp delivery system was evaluated in a short-term pilot study. Iridotomies were created in 44 Eskimo eyes (23 patients) with occludable angles in Alaska's Kotzebue region. The laser was transported as regular baggage, was used in three villages (utilizing available facilities), and was operational within five minutes. Patent iridotomies were achieved in all eyes and with one pulse in 18 eyes (44%). Complications included transient bleeding from the iridotomy site in 23 eyes (52%), focal corneal opacities in 11 eyes (25%), and a transient immediate postoperative intraocular pressure elevation in nine eyes (20%). This appears to be the first portable laser system that can be used in frontier areas and underdeveloped nations to prophylactically treat pupillary-block glaucoma.

Aged↗
PubMed1986

Q-switched neodymium-YAG laser iridotomy in patients in whom the argon laser fails.

We conducted a short-term prospective clinical study to evaluate Q-switched neodymium-YAG laser iridotomy in 33 eyes with pupillary block glaucoma in which the argon laser was unable to create an iridotomy. These eyes had chronic angle closure glaucoma (11 eyes), acute angle closure glaucoma (five eyes), pseudophakic pupillary block (seven eyes), uveitic pupillary block (three eyes), and contralateral eyes (five eyes); also included were both eyes of a patient with a head tremor. In all eyes, a patent iridotomy was created in one treatment session, with a mean of 5 +/- 5 pulses and a mean total energy of 55 +/- 120 millijoules. Complications included iridotomy closure (two eyes with preexisting active uveitis), focal nonprogressive corneal opacities (six eyes), and minimal bleeding from the iridotomy margin (12 eyes). Q-switched neodymium-YAG laser iridotomy appears to be an effective next step in the management of pupillary block glaucoma prior to surgical iridectomy when argon laser iridotomy fails.

Argon↗