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Biomedical subjects

R P Mills

Publications and source records attributed to R P Mills.

At least 19 recordsLinked to original sources
PubMed1999

Mitotic effect of autologous blood injection and diode laser bleb revision on rabbit filtration blebs.

OBJECTIVE: To investigate the effect of intrableb autologous blood injection and diode laser bleb revision on cellular proliferation in filtration blebs of rabbits. METHODS: Bilateral filtration surgery with mitomycin was performed on 19 white 2.5- to 3-kg New Zealand rabbits. Autologous blood injection (n = 9) or diode laser bleb revision (n = 10) was performed on blebs of right eyes (intervention eyes) on day 14 after filtration surgery. The blebs of the left eyes served as controls. Cellular proliferation was assessed by in vivo incorporation of 5-bromo-2'-deoxyuridine (BrdU), after BrdU, 10 mg/kg, was injected via the ear vein on days 15, 16, and 18. The rabbits were euthanized on day 21. Conjunctival sections were stained with hematoxylin-eosin for total cell counts and with anti-BrdU antibody for counts of proliferating cells. The BrdU labeling index was calculated by dividing the mean proliferating cell count by the mean total cell count. RESULTS: The BrdU labeling index was significantly increased in the blood-injected eyes as compared with the control eyes (P = .03). The BrdU labeling index was increased in the diode laser-revised eyes as compared with the control eyes, approaching significance (P = .06). Intraocular pressure increased significantly in the eyes that underwent bleb interventions in both groups from baseline and compared with the control eyes. CONCLUSIONS: Intrableb autologous blood injection and diode laser bleb revision stimulate cellular proliferation in the rabbit filtration bleb, which may contribute to the rise in intraocular pressure observed clinically after these interventions.

Animals↗
PubMed1999

Continuous visual field test supervision may not always be necessary.

OBJECTIVE: To assess the effect of supervision on computerized visual field (VF) performance and to determine what patient characteristics predict poor unsupervised performance. DESIGN: Randomized, crossover, cross-sectional, clinical trial. PARTICIPANTS: Two hundred unselected patients with definite or suspect glaucoma or neuro-ophthalmic VF indication participated. INTERVENTION: All patients completed two 30-2 tests of one eye on a Humphrey perimeter, one with continuous active technician supervision and one without supervision after the initial 2 minutes of the test. MAIN OUTCOME MEASURES: Visual field reliability and global VF indices were measured. RESULTS: Supervision had a positive effect on overall reliability (P = 0.04) but not on individual reliability parameters or any of the global VF indices. There was no difference between Humphrey Field Analyzers I and II in the need for supervision. Predictors of need for supervision were low educational level and a prior test result with false-positive responses. Predictors of an unreliable test were advanced age and a prior test with a high proportion of fixation losses. CONCLUSION: Supervision is necessary for those with risk factors for unsatisfactory perimetry such as advanced age, low level of formal education, and prior test results with false-positive responses or high fixation losses; in the remainder, omission of supervision can be considered.

Aged↗
PubMed1999

The effects of compression sutures on filtering blebs in rabbit eyes.

PURPOSE: To investigate the effect of compression sutures on filtering bleb cellularity in rabbit eyes. METHODS: Six New Zealand rabbits had bilateral filtering surgery. In the study eye, on postoperative day 14 a 10-0 nylon suture was placed that compressed the bleb. Five-bromo-2'-deoxyuridine (BrdU) was injected intravenously on days 15, 16, and 18. On day 21 histologic sections of the blebs were obtained. The total cell count was compared to the number of actively dividing cells (marked by anti-BrdU antibody). RESULTS: Study eyes had higher total cell counts (P = .004) on postoperative day 21, but the proportion of proliferating cells was not significantly different (P = .11). CONCLUSION: In rabbit eyes, bleb compression sutures were associated with more cellular components in the bleb compared to control eyes, but did not induce a higher level of cellular proliferation.

Animals↗
PubMed1999

Core cutter for harvesting cortical bone grafts for reconstructions of the ossicular chain.

Cortical bone autografts have been used to reconstruct the ossicular chain for more than 30 years. We describe a core cutter burr which facilitates the rapid harvesting of grafts which are suitable for a number of different types of reconstruction. The use of these grafts to reconstruct different defects of the ossicular chain is also presented.

Bone Transplantation↗
PubMed1998

Comparison of the effect of latanoprost 0.005% and timolol 0.5% on the calculated ocular perfusion pressure in patients with normal-tension glaucoma.

PURPOSE: To compare the calculated mean ocular perfusion pressure at the end of 3 weeks' treatment with latanoprost 0.005% once daily or timolol 0.5% twice daily in normal-tension glaucoma patients. METHODS: In a three-center, double-masked, randomized, crossover study, 36 patients were allocated to two treatment groups; one received 3 weeks each of placebo, latanoprost, placebo, and timolol, whereas the other group had placebo, timolol, placebo, and latanoprost. Intraocular pressure and resting systemic blood pressure were measured at 9 AM, 12 noon, and 4 PM. Ocular perfusion pressure was calculated for each time period as well as the mean of three values (daytime average). Systemic blood pressure and heart rate were also recorded at 30-minute intervals during the last 24 hours of each treatment period. RESULTS: The average daytime mean ocular perfusion pressure (mean +/- SEM) following latanoprost treatment was 53.2 +/- 1.4 mm Hg, an increase of 8% from the latanoprost run-in period, compared with 50.9 +/- 1.1 mm Hg following timolol treatment, an increase of 2% from the timolol run-in period (P < .05, ANOVA). Timolol reduced the blood pressure. The difference in mean daytime and nighttime systolic blood pressure measurements as well as nighttime diastolic blood pressure was about 5 mm Hg between the latanoprost and timolol treatments. The daytime and nighttime heart rates were also slower during the timolol treatment. CONCLUSION: Because ocular perfusion pressure may be important in some glaucomatous patients, latanoprost appears to affect ocular perfusion pressure more favorably than timolol does in patients with normal-tension glaucoma.

Adrenergic beta-Antagonists↗
PubMed1998

Correlation of quality of life with clinical symptoms and signs at the time of glaucoma diagnosis.

PURPOSE: To examine the relationship between clinical measures of visual function and patient-reported measures of symptoms and health status in a large cohort of glaucoma patients at the time of diagnosis. SUBJECTS AND METHODS: The 607 patients in the Collaborative Initial Glaucoma Treatment Study (CIGTS) received standardized examinations of visual acuity and visual field at enrollment. In addition, they completed a health-related quality-of-life instrument, which included the Visual Activities Questionnaire (VAQ), Sickness Impact Profile (SIP), a symptom and a comorbidity chart, a question about their degree of worry about becoming blind, and many other items. RESULTS: The SIP total and dimension scores correlated only weakly, and not significantly, with visual acuity and visual field measures. The VAQ total and subscale scores, particularly the peripheral vision subscale, correlated weakly and significantly with visual acuity and visual field scores, especially those from the better eye. Worry about blindness and symptoms attributed to glaucoma correlated weakly but significantly to visual field scores from the worse eye. Attempts to improve correlations by scoring the visual fields differently, including only paracentral and pericentral test locations in the scores, and simulating binocular visual field scores were largely unsuccessful. CONCLUSIONS: At diagnosis, most patients were relatively free of glaucoma-induced impairments, so clinical measures were poor predictors of a patient's perception of health-related quality of life. The vision-specific VAQ and glaucoma-related symptom score correlated better than the generic SIP with clinical measures at the time of enrollment into CIGTS.

Adult↗
PubMed1998

Quantitative nerve fiber layer measurement using scanning laser polarimetry and modulation parameters in the detection of glaucoma.

PURPOSE: To assess a new method of processing quantitative nerve fiber layer (NFL) measurement data to distinguish between eyes with glaucoma of varying severity and normal eyes, using information obtained by scanning laser polarimetry. PATIENTS AND METHODS: Scanning laser polarimetry measurements of the peripapillary NFL within a 10-pixel band located 1.8 disc diameters from and concentric with the disc margin were obtained from 36 normal eyes, 69 eyes with glaucoma, 7 eyes suspected of being glaucomatous, and 19 eyes with ocular hypertension. These values then were examined using new data processing "modulation" parameters in which the average of the nasal and temporal minimum retardation is subtracted from the retardation in the superior or inferior region of the peripapillary NFL. The ability of modulation parameters to differentiate between normal and glaucomatous eyes was compared with other parameters based either on the sum of retardation values in the superior or inferior region, or on the ratio of values in the superior or inferior region to the nasal region. RESULTS: Differences in mean polarimetric retardation between normal eyes and eyes with glaucoma were significant for all parameters, but were greatest when modulation parameters were used and were significantly greater for two modulation parameters. The range of values showed considerable overlap between all groups of eyes. Eyes with ocular hypertension had mean values intermediate between normal eyes and eyes with early glaucomatous damage. CONCLUSION: The use of new modulation parameters increases the ability of quantitative NFL measurement to distinguish between eyes with glaucoma of varying severity and normal eyes.

Adult↗
PubMed1998

Correlation of peripapillary nerve fiber layer thickness by scanning laser polarimetry with visual field defects in patients with glaucoma.

PURPOSE: To assess the correlation between the results of peripapillary scanning laser polarimetry of the retinal nerve fiber layer (NFL) and automated visual field testing in patients with open-angle glaucoma. METHODS: Visual fields from 42 patients with varying stages of glaucoma were scored using Collaborative Initial Glaucoma Treatment Study (CIGTS) criteria. Mean deviation, pattern standard deviation, and CIGTS total and hemifield visual field scores were correlated with peripapillary NFL thickness measured by scanning laser polarimetry using summed, ratio-based, and modulation parameters. RESULTS: Mean deviation and CIGTS total and upper hemifield score were significantly correlated with NFL retardation values using summed, ratio-based, or modulation parameters. The CIGTS lower hemifield score was significantly correlated with modulation parameter values only. Correlation of CIGTS scores was significantly stronger with modulation parameters than with summed parameters (total and lower hemifield scores) and ratio-based parameters (lower hemifield only) by the Hotelling t test. CONCLUSION: Relative NFL thickness measured by scanning laser polarimetry correlates well with visual field defects seen on Humphrey perimetry of patients with open-angle glaucoma. Modulation parameters, in which the superior and inferior peak NFL thickness (as measured by scanning laser polarimetry) are adjusted for the patient's average minimum NFL thickness in the nasal and temporal quadrants, provided stronger correlation than summed parameters and ratio-based parameters.

Adult↗
PubMed1998

Detection of optic disc changes with Glaucoma-Scope probability maps.

PURPOSE: To test whether a statistical method using a probability map could detect true changes in optic disc topography. METHODS: The average of three Glaucoma-Scope images (Ophthalmic Imaging Systems were used for analysis at each of two sessions. A Glaucoma-Scope probability map was constructed for each eye using statistical methods. The proportion of topographic locations with p values less than 0.05 on a modified two-sample t test (p-proportion) and the difference in the mean position of the disc (MPD) from two imaging sessions were calculated. Two pairs of stereoscopic disc photographs for 43 eyes with longitudinal follow-up were evaluated for change by four experienced glaucoma specialists masked to patient clinical information. Clinical change was considered to have occurred when the assessments of at least three of the four specialists were agreed on. The cutoff values for p-proportion and change in MPD that provided 95% specificity were calculated using a separate sample of 69 subjects who had serial images taken at two separate sessions on the same day, and thus showed no clinical change in the optic disc. RESULTS: The cutoff values of 95% specificity for the p-proportion and the change in MPD were 18% and 25.1 microns, respectively. Of 43 eyes with longitudinal follow-up, 14 showed definite clinical change. Sensitivity of the p-proportion and change in MPD for detecting this change was 100% and 85.7%, respectively. For all 43 patients with longitudinal follow-up, the percent change in intraocular pressure (IOP) correlated strongly with both the p-proportion and the change in MPD. CONCLUSION: Using data obtained with the Glaucoma-Scope, a statistical method based on probability mapping can be used to detect true changes in disc topography. The p-proportion was more sensitive than change in MPD in detecting clinical change in the study eyes. This statistical methodology may also be applicable for interpretation of data obtained with other optic disc analyzers.

Adult↗
PubMed1997

Reduced intraocular pressure and increased ocular perfusion pressure in normal tension glaucoma: a review of short-term studies with three dose regimens of latanoprost treatment.

Currently used ocular hypotensive agents do not effectively lower intraocular pressure (IOP) in some normal-tension glaucoma (NTG) patients. The prostaglandin F2 alpha analogue, latanoprost, has been shown to reduce IOP in normal subjects and ocular hypertensive glaucoma patients by increasing uveoscleral outflow. This mechanism is expected to be particularly effective in the lower IOP range that is typical of NTG. To date, three dose regimens of latanoprost have been shown to reduce IOP significantly in NTG. The IOP reductions of 14.2% and 15% obtained with twice-daily application of 0.0015% and 0.006% latanoprost, respectively, were comparable to the modest IOP reduction that has been reported for other glaucoma drugs in NTG. In contrast, once-daily application of 0.005% latanoprost resulted in a 21.4% IOP reduction. In another study that included 24-hour monitoring of systemic blood pressure and heart rate in NTG patients, the ocular perfusion pressure was found to improve more on once-daily 0.005% latanoprost than on twice-daily treatment with 0.5% timolol. Thus, once-daily 0.005% latanoprost appears to be a more effective and more convenient ocular hypotensive agent for treating NTG than currently used glaucoma drugs. However, long-term studies will ultimately be needed to establish the efficacy of this new drug to delay or prevent the progression of visual field loss in normal tension glaucoma.

Administration, Topical↗
PubMed1997

A multicenter comparison study of the Humphrey Field Analyzer I and the Humphrey Field Analyzer II.

PURPOSE: The purpose of the study is to determine the comparability of the 30-2 full-threshold program in the original Humphrey Field Analyzer (HFA) I to the same test procedure in the new Humphrey Field Analyzer II. METHODS: At each of five clinical centers, one eye of patients with ocular hypertension and normal visual fields, patients with early glaucomatous visual field loss, and patients with more advanced visual field loss were tested with the two instruments plus a retest on a separate HFA I. All participants had undergone at least one prior visual field examination. To minimize the influence of any residual learning or fatigue effects, the order of testing for the three visual field examinations was counterbalanced across subjects. A total of 250 patients were tested (81 patients with ocular hypertension, 81 patients with early glaucomatous visual field loss, and 88 patients with more advanced glaucomatous visual field loss). RESULTS: No statistically significant differences were observed between thresholds, visual field indices, or reliability indices obtained with the HFA I and the HFA II. The small differences between the two instruments were equivalent to the variation observed for test-retest measures using only the HFA I. These results were consistent across the range of visual field characteristics shown by the ocular hypertensive, early glaucoma, and moderate glaucoma patient groups. CONCLUSIONS: The authors' results indicate that there are no differences in the visual field results obtained with the HFA I and the HFA II. These findings suggest that with careful attention to test protocols, the HFA I and HFA II may be used interchangeably to observe patients, even within the context of multicenter clinical trials.

False Negative Reactions↗
PubMed1997

The effect of a brief education program on glaucoma patients.

PURPOSE: To assess our patients' knowledge of glaucoma and to measure the effect of a brief education program on their understanding of glaucoma. METHODS: Patients attending glaucoma clinics at a university and a Veterans' Affairs hospital were randomized into two groups: "exposed" and "unexposed" to a simple education program of a video and brochures. Glaucoma knowledge was assessed twice by an oral questionnaire, at 2 weeks and 6 months after randomization plus or minus education. RESULTS: Younger patients and those with more years of formal schooling knew more about glaucoma. Two weeks after the education program, the exposed group performed significantly better than did the unexposed group. Analysis of the results showed benefit from both brochures and video. This effect of education was not seen at retesting 6 months later. CONCLUSION: Older patients and those with less formal education know less about glaucoma. A brief, simple education program can significantly improve levels of knowledge about glaucoma, even in a relatively well-informed population. However, patient education must be repeated to maintain a useful effect.

Aged↗
PubMed1997

Probability maps of sequential glaucoma-scope images help identify significant change.

PURPOSE: The purpose of this study was to identify areas of the optic disc showing high variability of repeated depth measurements, and to minimize the effect of baseline variability in interpretation of possible change over time using the Glaucoma-Scope. METHODS: Seventy-four eyes from 70 subjects were analyzed with the Glaucoma-Scope. Three images were obtained on each of two separate sessions during the same day. At each location, the mean depth of the three images for each session was calculated to create a "baseline image." A contour map of standard deviation (SD) values at each topographic location was created for each subject reflecting local variability at different parts of the disc. The contour map and disc photograph were compared to determine what photographic features predicted high variability. A modified two-sample t-test was used at each topographic location to obtain p-values for the likelihood that a difference in mean depth between sessions was attributable to measurement variability alone. RESULTS: Contour plots of SD for most subject eyes showed high variability in steeply sloped areas of the disc and along large blood vessels, with low variability near the cup center. The use of probability plots for significance of depth changes between test sessions automatically accounted for increased pointwise variability. The proportion of topographic locations showing statistically significant change but attributable to chance variation when no true change has occurred approximated the predicted proportion based on our modified t-test model. CONCLUSION: A contour map of standard deviations of depth based on Glaucoma-Scope baseline images can identify areas of the disc with high variability. Statistical methods such as probability maps that account for local variability in the baseline image may be helpful in distinguishing true change from artefactual change over time.

Adolescent↗
PubMed1996

Tympanic membrane perforations in children.

We have assessed children with perforations of the pars-tensa presenting to an otolaryngology clinic over a 7-year period. We found that over 70% of the perforations followed the insertion of a ventilation tube. Using a novel method of dividing the tympanic membrane into quadrants, we were able to assess the sites and grade the size of perforations. The most common site of involvement, in all perforations, was the antero-inferior quadrant. With the exception of perforations following the use of T-tubes, we found little difference between the sites, sizes and hearing levels of ventilation tube and non-ventilation tube related perforations. Larger perforations resulted in a greater degree of hearing loss.

Child, Preschool↗
PubMed1996

Long-term survival of Molteno glaucoma drainage devices.

PURPOSE: To evaluate the long-term outcome of the Molteno implant drainage device using survival analysis. METHODS: A retrospective chart review was performed on 77 eyes of 71 patients that underwent Molteno implantation for intractable glaucoma unresponsive to conventional management from October 1984 to April 1990 at the University of Washington Eye Center and had at least 6 months of follow-up data. Success was defined as a postoperative intraocular pressure of 22 mmHg or lower with (qualified success) or without (complete success) glaucoma medications and no additional glaucoma surgery, phthisis, or loss of light perception. RESULTS: The median follow-up was 44 months (range, 6-107 months). Indications for Molteno implantation were aphakia/pseudophakia (n=24), neovascular glaucoma (n=20), uveitic glaucoma (n=12), failed trabeculectomy (n=9), traumatic glaucoma (n=8), and congenital glaucoma (n=4). The total success was 57% (23% complete; 34% qualified) at the last follow-up. Kaplan-Meier survival curves demonstrated a continuous and relatively linear attrition of success over at least 5 1/2 postoperative years. The uveitic glaucoma group had the highest success rate of 75%. Eyes with neovascular glaucoma failed significantly more frequently than those with uveitic glaucoma (P<0.01). There was no significant difference in outcome based on sex, race, single versus double plate, anterior chamber versus posterior chamber tube placement, or two-stage versus single-stage surgery. Younger age was associated with a significantly higher failure rate after controlling for glaucoma category (P<0.01). CONCLUSION: The Molteno implant drainage device offers a reasonable long- term outcome in eyes with intractable glaucomas. However, an ongoing rate of failure, not unlike that seen after other filtration surgery, is to be expected.

Adolescent↗
PubMed1996

The management of unilateral vocal cord palsy by augmentation using autologous fat.

Augmentation of the vocal cord with Teflon paste has been one of the mainstays of treatment of a unilateral vocal cord palsy. Recently the licence for Teflon in the UK has been withdrawn, creating the need for an alternative. Over the last 2 years we have been using autologous fat harvested from the abdominal wall for this purpose. Fat is more difficult to work with than Teflon and we have developed a modified injection gun in order to facilitate the injection of the fat. The technique has been used in 14 patients with improvement of the voice in eight.

Adipose Tissue↗