Intraoperative intracameral carbachol in phacoemulsification and posterior chamber lens implantation.

PURPOSE: To evaluate the use of intraoperative intracameral carbachol in association with phacoemulsification and posterior lens implantation. METHODS: We prospectively randomly assigned 41 eyes (41 patients) to receive either placebo or a 50:50 dilution of carbachol 0.01% after intraocular lens insertion and phacoemulsification. RESULTS: Twenty-one eyes of 21 patients treated with intracameral carbachol showed a statistically significant (P = .0373) reduction in intraocular pressure (15.9 mm Hg) at 6 hours postoperatively compared with 20 eyes of 20 patients who had received placebo (20.4 mm Hg). At day 1, the carbachol group measured 15.0 mm Hg vs 17.6 mm Hg for placebo (P = .0376), and a 1.5-line improvement in visual acuity in the carbachol vs the placebo group was noted (P = .0263), which was maintained on glare testing. On quality of life testing using a modified SF-36 test, carbachol-treated patients within the first postoperative week more often attempted to descent stairs in both bright (P = .007) and dim (P = .037) light than did patients treated with placebo. At month 2, no difference was observed between groups except that depth of focus was statistically greater in the carbachol group (P = .025). Safety was similar between the two groups in terms of ocular and systemic adverse events. CONCLUSIONS: Patients treated with carbachol intracamerally after phacoemulsification and posterior chamber lens implantation demonstrate lower intraocular pressure within the first day postoperatively. These findings are associated with improved visual acuity and potentially greater ambulation in bright light within the first postoperative week.

Daily cost of beta-adrenergic blocker therapy.

OBJECTIVE: To evaluate the daily cost of beta-blocker therapy among commercially available products. METHODS: Ten different beta-adrenergic blocker preparations, each in 10-mL bottles (except Timoptic-XE [Merck brand of timolol maleate gel-forming solution], which was in a 5-mL bottle), were acquired from a local pharmacy. Each of 10 subjects dispensed 10 drops from each bottle onto an analytical scale. The mean drop volume for each preparation was then calculated. The fill volume of each bottle and the amount of each medicine that was wasted upon dispensing also were determined. Additionally, 60 pharmacies in the United States were randomly chosen to determine the average cost of each preparation studied. Based on all data obtained, an average daily cost of each medicine was calculated. RESULTS: The generic formulation of timolol maleate (Falcon) ($0.55) and Betimol (Ciba Vision Ophthalmics brand of timolol hemihydrate) ($0.57) demonstrated the lowest cost per day of therapy. In contrast, Betoptic-S (Alcon brand of betaxolol hydrochloride) ($1.60) and Betagan (Allergan brand of levobunonol hydrochloride) ($1.35) had the highest daily cost of therapy. Ocupress (Otsuka America brand of carteolol hydrochloride) had the smallest drop volume (31 microL) and Timoptic-XE had the highest (49 microL). Most preparations were close to their stated bottle fill volume. The amount of wasted medicine varied and was least with Ocupress (27%) and greatest with Betoptic-S (54%). The mean pharmacy price for a 10-mL bottle was lowest for OptiPranolol (Bausch & Lomb brand of metipranolol) ($25.51) and Betimol ($28.28); Betoptic-S ($44.80) and Betagan ($43.67) were the most expensive. CONCLUSION: Although all commercially available beta-adrenergic blockers effectively lower intraocular pressure, one differential factor between medicines is cost, which may be influenced by the price at the pharmacy, volume of medication per bottle, drop size, and medicine wastage.

Topical anesthesia during infant eye examinations: does it reduce stress?

We studied the effect of topical anesthesia on infant stress and corneal haze during the routine eye examination for retinopathy of prematurity. Using a double-blind protocol, 55 premature infants weighing less than 1501 g at birth were selected randomly to receive normal saline or proparacaine HCl 0.5% eye drops as a corneal wetting agent at their initial eye examination. Before, during, and after the procedure, infant stress was evaluated by heart rate, respiration rate, blood pressure, and transcutaneous oxygen saturation. Subjective assessment of the infant's cry intensity and corneal haze also were recorded. Adequate data were collected on 42 patients. Using analysis of variance and chi-square tests, we found no difference in any of these parameters between the two patients groups. These data suggest that topical anesthetic agents offer no advantage over normal saline eye drops during the examination of premature infants.

Prediction of postoperative visual acuity in patients with total glaucomatous cupping using the Potential Acuity Meter and automated perimetry.

We evaluated the effectiveness of using the Potential Acuity Meter (PAM) and automated perimetry to predict postoperative vision in 30 advanced glaucoma patients following combined cataract extraction and trabeculectomy. Using the binomial distribution at alpha = 0.05, PAM and automated perimetry individually were significantly useful in predicting postoperative vision of 20/40 or better. Automated perimetry, but not PAM, was useful in predicting worse than 20/40 vision. Used together, automated perimetry and PAM testing were significantly useful in predicting vision worse or better than 20/40.

Predicting success of external cephalic version.

OBJECTIVE: Many authors have identified prognostic factors for external cephalic version success, but there has not been an attempt to integrate these factors into a simple, quantitative scoring system for predicting version success. Nor have any prognostic factors been prospectively tested. STUDY DESIGN: We examined the clinical characteristics of 108 consecutive breech versions performed between 1984 and 1986. These characteristics were evaluated by stepwise linear regression and discriminate analysis to identify those factors associated with success. Five factors explained the majority of the variability in outcome (parity, placental location, dilation, station, and estimated fetal weight). A model was developed to incorporate the trends identified among these five variables to create a scoring system similar to that of Bishop. This scoring system was then applied to 286 women undergoing external cephalic version since October 1986. RESULTS: There was a positive relationship between a rising version score and the likelihood of successful breech version. No versions were successful with a score < or = 2, and all breech versions were successful with a score of 9 or 10. The results of the version score may have significantly altered physician recommendations in more than one third of cases. CONCLUSION: We believe that this simple, quantifiable scoring system is a refinement in our ability to predict the likelihood of external cephalic version success.

Factors associated with visual loss in patients with advanced glaucomatous changes in the optic nerve head.

We evaluated factors associated with decreased or stable visual function in 72 patients with primary open-angle glaucoma and complete cupping of the optic disk who were followed up five years or more. We found a significantly lower mean (15.4 +/- 2.7 mm Hg) and peak (24.5 +/- 6.9 mm Hg) intraocular pressure in those patients whose vision remained stable vs those whose vision decreased (21.3 +/- 3.2 and 39.2 +/- 11.0 mm Hg, respectively) (t-test, P < .001). Additionally, the variance of each patient's individual intraocular pressure readings measured during the follow-up period was lower in the group with stable vision (4.5 mm Hg) than in those in whom vision decreased (9.0 mm Hg) (F test, P < .001). Stepwise discriminant analysis disclosed that mean intraocular pressure, variance of an individual's intraocular pressure measurements over time, history of argon laser trabeculoplasty, and compliance with therapy discriminated 92.9% of patients (52 of 56) whose vision remained stable and 87.5% of patients (14 of 16) whose vision decreased. Reduction of intraocular pressure and compliance with therapy are important in patients with complete glaucomatous cupping of the optic disk.

Threshold variation in automated perimetry.

A physiologic fluctuation in threshold levels exists in automated perimetry, which is greater in glaucoma and ocular hypertensive patients than in normal subjects. Fluctuation increases with greater eccentricity from fixation and in areas of reduced retinal sensitivity. Other factors related to automated perimetry testing potentially may influence threshold fluctuation including: a learning effect, reliability, pupil size, age, and the mode of stimulus presentation. Statistical software may aid in analyzing both the single field and the changes between successive fields. However, statistical programs cannot replace physician judgment, and all factors that may influence threshold levels should be considered when interpreting automated visual fields.

Histologic differences in the conjunctiva of black and white glaucoma patients.

We compared perioperative conjunctival biopsy specimens from 31 consecutive trabeculectomy patients to determine if there were any histologic differences between black and white glaucoma patients. We found a statistically significantly greater mean and distribution of mast cells and neutrophils in the white patients. No significant difference was found in the mean number of goblet cells, eosinophiles, macrophages, fibroblasts, plasma cells, or lymphocytes; or in thickness of the epithelium, vascular density, or collagen or mucopolysaccharide staining. We conclude that histological conjunctival factors that could be evaluated preoperatively probably are not related to the poor results in black patients of filtration surgery noted by some investigators.

Association of reliability with reproducibility of the glaucomatous visual field.

We studied 207 glaucoma patients (207 eyes) who had two successive visual tests on the Humphrey Field Analyzer to determine the association of unreliability (> 10% incidence of a missed catch trial test) with threshold variation. We found that in patients where one visual field showed > 30% false negative or positive errors, and the other visual field also was unreliable, a significant increase in the variance of the mean defect existed from reliable patients (p < 0.05). Of patients who had only one of two visual fields which was unreliable (from false negative errors), only those with marked glaucomatous visual field loss (< -15 dB depth of defect) showed a greater variance in mean defect between examinations over reliable patients (p < 0.05). In total, 41 patients (19.8%) had unreliable visual fields associated with statistically increased threshold variation. This study suggests that patient reliability should be considered when interpreting changes in threshold between automated visual field examinations.

Pattern discrimination perimetry in patients with glaucoma and ocular hypertension.

We compared the results of the pattern discrimination perimeter to the program 30-2 on the Humphrey Field Analyzer (Humphrey, Inc., San Leandro, California) in 93 consecutive patients with ocular hypertension and glaucoma and 30 control patients. In 20 patients with ocular hypertension, a significantly greater number of glaucomatous defects were noted on pattern discrimination perimetry (ten patients) than on the program 30-2 (two patients) (P less than .05, Wilcoxon signed rank test). The diversity in diagnoses found on pattern discrimination testing was not explained by age, intraocular pressure, refraction, number of glaucoma medicines, race, presence of vascular disease, optic disk status, or pupil size. In contrast, in 73 patients with glaucoma no statistical difference in the severity of diagnoses was noted between perimeters (P greater than .05, Wilcoxon signed rank test). These results suggest the potential value of pattern discrimination perimetry as a visual function test in patients with glaucoma and in defining subsets of patients with ocular hypertension not found with conventional automated perimetry.

Long-term and short-term fluctuation in pattern discrimination perimetry.

We studied threshold fluctuation with the pattern discrimination perimeter in 24 healthy subjects at 56 locations within the central 30 degrees. This perimeter evaluates a subject's ability to discriminate a patterned stimulus measured by a percentage scale. We found an intraindividual fluctuation of 10.52% and an interindividual fluctuation of 8.78%. A statistically increased intraindividual, but not interindividual fluctuation was noted with increasing eccentricity from fixation (P less than .05, Bartlett's test). However, no correlation in fluctuation was noted with advancing age or increasing false-positive errors (P greater than .05, correlation coefficient). Also, no difference in fluctuation between superior or inferior hemifields was observed (P greater than .05, Student's t-test). The average threshold across all subjects was 54.3%, which provided an upper limit of normal, two standard deviations from the mean, of less than 80% for most locations. This study indicates that fluctuation should be considered when interpreting pattern discrimination fields, but that the extent of fluctuation generally allows for an adequate separation between normal and abnormal measurements.

The effect of stimulus duration upon the components of fluctuation in static automated perimetry.

We studied the effect of varying the stimulus duration time on the components of fluctuation in static automated perimetry by testing 20 healthy subjects on the Humphrey Field Analyser within the central 20 degrees of vision. We found the total fluctuation at a stimulus duration of 0.065 s, to be 3.22 decibels (dB); 0.1 s, 3.22 dB; 0.2 s, 3.34 dB; 0.3 s, 2.95 dB; 0.4 s, 3.24 dB; and 0.5 s, 3.22 dB. Little difference was observed in the individual components (short-term, long-term homogeneous, long-term heterogeneous and inter-individual) or total fluctuation with an increasing stimulus presentation time when evaluated over the entire visual field or in a pointwise fashion. This study suggests that the stimulus duration within the range of times studied has little effect on the components or total fluctuation in healthy individuals.

The effect of background intensity on the components of fluctuation as determined by threshold-related automated perimetry.

We studied the effect of various background intensities on the components of fluctuation by testing 20 healthy subjects on the Humphrey Field Analyzer. Our results show little difference in the total fluctuation between two low photopic background intensities similar to those commonly used on commercial perimeters: 3.02 dB for 31.5 apostilbs (asb) and 2.77 dB for 3.15 asb. However, an increase in total fluctuation (3.74 dB for 0.315 asb and 4.24 dB for 0.0315 asb) as well as in its short-term, long-term heterogeneous, and interindividual components was seen at mesopic background intensities as compared with the low photopic range. This study suggests that in healthy individuals, little difference exists in the fluctuation resulting from differences in background intensities commonly used on commercial perimeters, whereas mesopic illumination may increase the variability of threshold responses.

Threshold variability using different Goldmann stimulus sizes.

We tested 10 healthy subjects on the Humphrey Field Analyzer using Goldmann stimulus sizes I-V to determine the effect of varying the area of the stimulus upon threshold fluctuation. Our results show similar components of fluctuation for the size III stimulus as in past studies. However, an increased total fluctuation was observed for Goldmann stimulus sizes I (3.69 decibels) and II (3.17 decibels) and a similar fluctuation for stimulus sizes IV (2.64 decibels) and V (2.51 decibels) as compared to stimulus size III (2.52 decibels). The study suggests no advantage results in reduced threshold fluctuation by changing the Goldmann stimulus from a size III when testing normal individuals on the Humphrey Field Analyzer.

Intellectual and adaptive functioning in individuals with Down syndrome in relation to age and environmental placement.

The cognitive and adaptive capacities of 130 individuals with Down syndrome were investigated as a function of age and environmental placement. Intellectual deterioration occurred whether individuals resided at home or in an institutional setting. Social/adaptive deterioration also occurred but with the least decline for those individuals who resided in institutional settings.

Sample size determination in clinical trials with an emphasis on exponentially distributed responses.

Sample size determination in clinical trials (and other similar studies) depends on a number of factors including the distribution of patient survival (remission) times, available estimates of the requisite parameters of the distribution under the null and alternative hypotheses, sizes of the Type I and Type II errors, and the length of the clinical trial, which in turn determines whether there are many, few, or no censored observations with regard to patient survival (remission). A further consideration is the patient recruitment period, which is assumed to begin simultaneously with the clinical trial but whose length is less than the length of the clinical trial. The purpose of this article is to explore the optimum lengths of the clinical trial and the recruitment period on the basis of minimizing the expected cost of the trial. A specified cost function, patient entry distribution, and exponential survival distribution are all assumed, primarily for illustrative purposes.

Normal range of plasma fibrinogen.

The automated thrombin time procedure was used to establish the normal range of fibrinogen concentration. Our results indicate a non-Gaussian distribution of this plasma protein and suggest this distribution is both age- and sex-dependent. The 95% confidence interval for the normal range of fibrinogen was 145-348 mg/dl.

Pharmacists' and physicians' responses to the South Carolina Product Selection Act of 1978.

The "Drug Product Selection act of 1978" became effective in South Carolina on January 1, 1979. All written prescription forms must be printed with two signature lines. Under the line at the left, "DISPENSE AS WRITTEN" must be printed. Under the line at the right, "SUBSTITUTION PERMITTED" must be printed. In addition, the pharmacist must receive the patient's consent before substitution can occur. This study investigated the impact of the Act on physicians' prescribing habits and pharmacists' responses to drug product selection initially and 3 months after enactment. The data were analyzed according to the drugs prescribed, permitted substitutions, physicians' specialties, use of correct prescription blank, drug category, date, and drug actually dispensed. Physicians permitted substitution for 27.19 percent of all prescriptions written. There were 499 prescriptions out of 1,835 authorizing substitutions. A total of 127 of these drugs were for single-source items, as 162 were written for generic items. In the remaining 210 prescriptions for brand name items, pharmacists selected another brand only 24 percent of the time.