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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
PubMed2002

Myringoplasty: does the size of the perforation matter?

Does the size of a tympanic membrane defect influence the success rate in myringoplasty? Many studies which have suggested that size does not affect results have included only small numbers of patients. After a power analysis to identify the size of groups needed to detect a clinically significant difference between the success rate of small and large perforations, a retrospective study was carried out to answer the question. A retrospective study of 423 myringoplasty-only operations showed that size does influence success; the success rate for small perforations was 74.1% compared with 56.0% for large perforations (P = 0.0003). Size also influences the change in four-frequency air conduction thresholds (small perforations +7.2 dB, large perforations +10.2 dB; t = 2.08, P = 0.039) in successful myringoplasties, a positive value indicating an improvement in hearing. This change is unlikely to be clinically significant. Patients should be made aware of these facts when informed consent is being obtained.

Audiometry↗
PubMed2001

Effects of cataract extraction with intraocular lens placement on scanning laser polarimetry of the peripapillary nerve fiber layer.

PURPOSE: To determine the effects of cataract extraction with intraocular lens placement on scanning laser polarimetry of the peripapillary nerve fiber layer. DESIGN: Cohort study. METHODS: Thirty-four eyes of 33 patients undergoing phacoemulsification cataract surgery with intraocular lens were imaged using the GDx Nerve Fiber Analyzer within 4 weeks before and at least 4 weeks after cataract surgery. Preoperative and postoperative mean images were compared. The effects of cataract severity and type, and intraocular lens material, were also examined. RESULTS: Comparison of preoperative and postoperative mean scanning laser polarimetry measurements revealed that eyes in which acrylic intraocular lenses (n = 11) were placed had a significant increase in scanning laser polarimetry for the total band circumference, and superior, inferior, and nasal quadrants (P < or =.041). Placement of silicone (n = 15) and polymethylmethacrylate (n = 8) intraocular lenses did not result in statistically significant changes in scanning laser polarimetry measurements. However, eight of 34 eyes (23.5%) had changes of 15% or more postoperatively in the total circumference measurement, including eyes with acrylic, silicone, and polymethylmethacrylate intraocular lenses. CONCLUSIONS: Cataract extraction with intraocular lens was associated with a statistically significant change in mean scanning laser polarimetry values in eyes that received an acrylic intraocular lens. In individual patients, clinically important changes (15% or greater) in scanning laser polarimetry measurements were not uncommon irrespective of intraocular lens type. New baseline scanning laser polarimetry measurements may be warranted in eyes that undergo cataract extraction with intraocular lens.

Acrylic Resins↗
PubMed2001

Interim clinical outcomes in the Collaborative Initial Glaucoma Treatment Study comparing initial treatment randomized to medications or surgery.

PURPOSE: To report interim outcome data, using all available follow-up through 5 years after treatment initiation, in the Collaborative Initial Glaucoma Treatment Study (CIGTS). DESIGN: Randomized clinical trial. PARTICIPANTS: Six hundred seven newly diagnosed glaucoma patients. METHODS: In a randomized clinical trial, 607 patients with newly diagnosed open-angle glaucoma were initially treated with either medication or trabeculectomy (with or without 5-fluorouracil). After treatment onset and early follow-up, patients were evaluated clinically at 6-month intervals. In addition, quality of life telephone interviews were conducted at similar frequency to the clinical visits. Patients in both arms of CIGTS were treated aggressively in an effort to reduce intraocular pressure (IOP) to a level at or below a predetermined target pressure specific for each individual eye. Visual field (VF) scores were analyzed by time-specific comparisons and by repeated measures models. MAIN OUTCOME MEASURES: VF loss was the primary outcome variable in CIGTS. Secondary outcomes of visual acuity (VA), IOP, and cataract were also studied. RESULTS: On the basis of completed follow-up through 4 years and partially completed through 5 years, VF loss did not differ significantly by initial treatment. Over the entire period of follow-up, surgical patients had a greater risk of substantial VA loss compared with medical patients. However, by 4 years after treatment, the average VA in the two groups was about equal. Over the course of follow-up, IOP in the medicine group has averaged 17 to 18 mmHg, whereas that in the surgery group averaged 14 to 15 mmHg. The rate of cataract requiring removal was greater in the surgically treated group. CONCLUSIONS: Both initial medical or initial surgical therapy result in about the same VF outcome after up to 5 years of follow-up. VA loss was greater in the surgery group, but the differences between groups seem to be converging as follow-up continues. When aggressive treatment aimed at substantial reduction in IOP from baseline is used, loss of VF can be seen to be minimal in general. Because 4 to 5 years of follow-up in a chronic disease is not adequate to draw treatment conclusions, these interim CIGTS outcomes do not support altering current treatment approaches to open-angle glaucoma.

Adrenergic beta-Antagonists↗
PubMed2001

The Collaborative Initial Glaucoma Treatment Study: interim quality of life findings after initial medical or surgical treatment of glaucoma.

OBJECTIVE: To present interim quality of life (QOL) findings in the Collaborative Initial Glaucoma Treatment Study (CIGTS) using all available follow-up through 5 years from treatment initiation. DESIGN: Randomized controlled clinical trial. PARTICIPANTS: Six hundred seven newly diagnosed patients with open-angle glaucoma from 14 clinical centers. INTERVENTION: Patients were randomly assigned to either initial medical therapy or initial trabeculectomy. After treatment initiation and early follow-up, patients received clinical and QOL evaluations at 6-month intervals. QOL assessments were administered by telephone at a centralized interviewing center. MAIN OUTCOME MEASURES: The CIGTS collected comprehensive QOL information that included both generic and vision-specific QOL measures. This article focuses on initial treatment group differences related to symptom reporting, as measured by a Symptom and Health Problem Checklist, and changes in daily visual functioning, as measured by the Visual Activities Questionnaire (VAQ). RESULTS: Across both treatment groups, there was an overall decline in the percent of participants reporting symptoms over time. Of 43 possible symptoms, 12 symptoms were reported with greater frequency by the surgically treated group and 7 symptoms more frequently by the medically-treated group. The surgical patients reported more total Symptom Impact Glaucoma (P = 0.005) and, in particular, more bother related to local eye symptoms. Very few treatment group differences were noted in visual functioning, although surgical patients reported more problems with activities related to their visual acuity (P = 0.024). The percentage of patients across treatment groups reporting worry about blindness was 50% at baseline but declined to approximately 25% over time. CONCLUSIONS: Overall, the QOL impact reported by the two treatment groups as measured by instruments used in this study is remarkably similar, with relatively few significant study group differences observed after up to 5 years of follow-up in the CIGTS. When significant differences in visual function have been detected using the VAQ, they are consistent with the clinical outcomes. To date, the most persistent QOL finding is the increased impact of local eye symptoms reported by the surgical group compared with the medical group. Although no changes are recommended in the treatment of newly diagnosed glaucoma patients at the time of this interim report, further follow-up will allow for more definitive answers to the QOL impact of these two treatment approaches.

Adrenergic beta-Antagonists↗
PubMed2001

Correlation of visual field with quality-of-life measures at diagnosis in the Collaborative Initial Glaucoma Treatment Study (CIGTS).

PURPOSE: To examine the relationship between various clinical measures of visual field and patient-reported measures of symptoms and health status in a large cohort of patients with glaucoma at the time of diagnosis. PATIENTS AND METHODS: The 607 patients in the Collaborative Initial Glaucoma Treatment Study received standardized examinations of visual field at enrollment. In addition, they completed a telephone-administered, health-related quality-of-life questionnaire, which included the Visual Activities Questionnaire (VAQ) and a symptom and health problem checklist. RESULTS: The Visual Activities Questionnaire total and subscale scores, particularly the peripheral vision subscale, correlated weakly but significantly with global visual field scores. Symptoms attributed to glaucoma also correlated weakly but significantly to visual field scores. Correlations with other visual field measures, including only central and pericentral test locations in the scores, did not strengthen the association, and simulating binocular visual field scores produced only slightly stronger correlations. CONCLUSIONS: At diagnosis, most patients were relatively free of glaucoma-related impairments. Various visual field measures derived from clinical visual field test data were only modestly associated with patients' perceptions of health-related quality of life. As the Collaborative Initial Glaucoma Treatment Study population is followed up longitudinally, it will be important to see whether these pertinent associations become stronger.

Disability Evaluation↗
PubMed2001

Effects of draining cochlear fluids on stapes displacement in human middle-ear models.

Displacement-frequency characteristics of the stapes footplate were measured in five human temporal bones before and after draining the vestibule. Measurements were made in the 0.125-8 kHz range at 80 dB input sound pressure level, using a laser Doppler vibrometer. A circuit model was also used to predict stapes displacement. The temporal bone studies show a slight decrease in stapes footplate displacement at low frequency, and little change above 1 kHz. The displacement change is not as great as that found by other investigators or predicted by the model. There is little difference in stapes motion in temporal bones when the inner ear is intact or drained.

Cochlea↗
PubMed2001

In vitro study of a multi-layer piezoelectric crystal attic hearing implant.

We have developed a prototype middle-ear hearing implant which uses a multilayer piezoelectric actuator. In this series of experiments the actuator was attached to the medial wall of the attic so that it makes contact with the body of the incus. Initial in vitro evaluation has been carried out using a laser vibrometer (Polytec CLV) to measure stapes velocity. Stapes displacement is calculated by mathematical integration. The device used in this way is particularly effective at transmitting high frequency sound to the stapes. When switched off the actuator impairs the transmission of sound to the ossicular chain at low frequencies, but this effect is only 7 dB at most. The stapes displacements resulting from the action of the implant have a linear relationship with the voltages used to drive the system. The high capacitance of the present actuator means that its power requirements are higher than that of other comparable devices. An optimal method of coupling the device to the incus has yet to be identified.

Acoustic Stimulation↗
PubMed2000

An anatomically shaped incus prosthesis for reconstruction of the ossicular chain.

An anatomically shaped incus replica prosthesis has been designed to reconstruct the ossicular chain. A series of in vitro studies on human temporal bones evaluated the acoustic performance of this prosthesis and compared it with a Causse partial ossicular replacement prosthesis (PORP). Pure tones in the frequency range 0. 125-8 kHz stimulated the tympanic membrane at sound pressure levels of 80, 90 and 100 dB. Measurements of the stapes footplate velocity were made with a laser interferometer. The acoustic function of the ossicular chain reconstructed with the incus replica prosthesis was found to be within 10 dB of that of the original intact ossicular chain, when both the upper and lower joints of the implant were rigidly fixed in place. It was shown that a rigid mechanical contact between the ossicular prosthesis and ossicles is a prerequisite for effective sound transmission. The anatomically shaped incus prosthesis gave a 15-dB improvement on the PORP at frequencies below 1.5 kHz.

Acoustic Stimulation↗
PubMed2000

Glaucoma screening as a vehicle for providing continuing medical education.

During a free screening at a major medical meeting, volunteer ophthalmologists educated attendees about glaucoma. A questionnaire was given to participants before and six months after the screenings to evaluate changes in their knowledge of glaucoma risk factors; the results showed a significant and enduring improvement (p < .02) in respondents' knowledge about glaucoma.

Clinical Competence↗
PubMed2000

Glaucoma screening using the scanning laser polarimeter.

PURPOSE: To determine the ability of scanning laser polarimetry (GDx Nerve Fiber Analyzer; Laser Diagnostic Technologies, Inc., San Diego, CA) to separate normal eyes and those considered likely to have glaucoma in a public glaucoma screening. METHODS: A 2-day public glaucoma screening program was held at two different institutions. Each subject underwent ophthalmologic examination, Humphrey perimetry (24-2 Fastpac program), and imaging using scanning laser polarimetry (GDx) in each eye for allocation into a diagnostic category: normal, ocular hypertensive, glaucoma suspect, or glaucoma. Results from the normal and glaucoma groups were analyzed, using modulation parameters calculated from a measurement band located 1.8 disc diameters from the disc, and selected parameters provided automatically by GDx software. Receiver operating characteristic curves were used to depict the sensitivity/specificity relationship at different GDx parameter cutoff levels. RESULTS: Of 200 subjects, 197 were classified; 122 were classified as normal, 23 were classified with ocular hypertension, 30 were classified as glaucoma suspects, and 22 were classified with definite glaucoma. Three subjects had ocular diseases other than glaucoma. The maximum area under the receiver operating characteristic curve for modulation parameters was 0.935, and for the GDx software parameters was 0.901. CONCLUSIONS: Scanning laser polarimetry may be useful in glaucoma screening.

Diagnostic Techniques, Ophthalmological↗
PubMed2000

Management of childhood otitis media with effusion by Scottish otolaryngologists.

A prospective audit of 5430 initial consultations and 1602 admissions to Scottish hospitals for surgical treatment of otitis media with effusion in childhood in ear, nose and throat departments throughout Scotland has been carried out. The results suggest that Scottish children are assessed by clinicians of appropriate experience when initially seen in outpatients and only a minority (30%) are listed for surgery following their first visit. Not all children have a hearing test at their initial clinic visit. In those cases where surgical treatment is not advised at the first visit, a policy of "watchful waiting" is preferred to medical treatment by most clinicians. Bilateral dry tap rates varied between zero in Forth Valley and 19% in Lanarkshire. Fifty one per cent of operations were carried out by consultants and only 3% by SHOs. "Best practice" for the initial management of childhood ear problems is widespread in Scotland but there is room for improvement. There is a need for review of the availability of paediatric audiology services.

Child↗
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

Screening for glaucoma with frequency-doubling technology and Damato campimetry.

OBJECTIVE: To assess frequency-doubling technology (FDT) perimetry (Humphrey Systems, San Leandro, Calif) and Damato campimetry (Precision Vision, Villa Park, Ill) for detecting glaucoma in a public glaucoma screening. METHODS: A 2-day public glaucoma screening was held at 2 different institutions. Each subject underwent 2 visual field screening tests (Damato campimetry and FDT perimetry in screening mode), an ophthalmologic examination, and Humphrey perimetry (24-2 FASTPAC) for each eye. Eyes were divided into 4 categories: normal, ocular hypertensive, glaucoma suspect, and definite glaucoma. The sensitivity and specificity of FDT perimetry and Damato campimetry for detecting glaucoma were estimated with receiver operating characteristic curves. RESULTS: Among 240 subjects who underwent FDT, the number identified as normal, ocular hypertensive, glaucoma suspect, and definite glaucoma was 151, 28, 35, and 26, respectively; among 175 subjects who underwent Damato campimetry, the numbers for the same groups were 118, 19, 19, and 19, respectively. The areas under the receiver operating characteristic curve for FDT perimetry and Damato campimetry were 0.925 and 0.883, respectively. The optimal sensitivity and specificity for FDT perimetry were 92% and 93%, while those for Damato campimetry were 53% and 90%, respectively. The average test time was 1 minute and 3 minutes per eye for FDT perimetry and Damato campimetry, respectively. CONCLUSION: Frequency-doubling technology perimetry was superior to Damato campimetry in this screening for glaucoma.

California↗
PubMed1999

Effects of contact lenses on scanning laser polarimetry of the peripapillary retinal nerve fiber layer.

PURPOSE: To determine the effects of contact lenses on scanning laser polarimetry of the peripapillary nerve fiber layer. METHODS: In a prospective study using the Nerve Fiber Analyzer (Laser Diagnostic Technologies, San Diego, California), retinal nerve fiber layer thickness in 22 subjects (51 eyes) was imaged with and without contact lenses (disposable and nondisposable daily wear soft and rigid gas permeable). Measurements of the circumference and of each quadrant were compared using paired Student t test. RESULTS: Nerve Fiber Analyzer measurements with and without contact lenses were not significantly different for any of the contact lens types tested (P > or = .11), using either hyperopic (to +4 diopters) or myopic (to -8.5 diopters) lenses. CONCLUSION: Contact lens wear and refractive power of the eye within the range tested do not significantly affect scanning laser polarimetry of the peripapillary nerve fiber layer.

Adult↗
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

Classification and staging of cholesteatoma.

No staging system for cholesteatoma has been universally adopted. All previous attempts failed to gain acceptance because of the lack of clinical relevance. We have devised a simple system to stage cholesteatoma which is based on the extent of lesion, ossicular condition and the preoperative complications. To illustrate the systems potential value, data from 119 new patients with cholesteatoma are presented and classified according to our proposed scheme. This shows a relationship between the stage of disease, ossicular damage and the occurrence of complications. The proposed staging system is potentially useful when considering the type of surgery required and when comparing published data reporting the results of tympanomastoid surgery.

Adolescent↗
PubMed1999

Prevention and management of hypotony after glaucoma surgery.

Postoperative hypotony is a common complication of glaucoma filtering surgery, particularly with adjunctive use of antifibrotic agents. Associated structural sequelae and reduced visual function may occur in some eyes, resulting in the low-pressure syndrome. Precautions may be taken intraoperatively and postoperatively to decrease the likelihood of hypotony. Sometimes, despite these measures, the low-pressure syndrome still can occur, the management of which can be difficult. When simple observation does not result in spontaneous resolution, several noninvasive and invasive techniques are available, targeted at the cause of low IOP.

Anterior Chamber↗