Biomedical subjects

Stuart C Carroll

Publications and source records attributed to Stuart C Carroll.

7 recordsLinked to original sources

PubMed2006

Correlation of retinal nerve fiber layer measured by scanning laser polarimeter to visual field in ischemic optic neuropathy.

OBJECTIVE: To evaluate the relationship between retinal nerve fiber layer (RNFL) measurement with scanning laser polarimetry (SLP) and standard automated perimetry (SAP) in nonarteritic anterior ischemic optic neuropathy (NAION). METHODS: In this prospective observational case series, all subjects (28 eyes with NAION) underwent SAP and SLP. The RNFL retardation measurements and visual field test points were grouped into 6 corresponding sectors. The contralateral uninvolved eye was used as control. The relationship between RNFL retardation and SAP was evaluated with the Spearman nonparametric technique and linear regression analysis. The main outcome measure was correlation of SLP RNFL parameters and SAP. RESULTS: Global and sectoral SLP parameters showed a significant difference in affected eyes compared with controls. The strongest correlations were seen between mean deviation and number (r = -0.524; P = .004), ellipse modulation (r = 0.5026; P = .006), and maximum modulation (r = 0.526; P = .004). Superior sectoral visual field indexes showed a strong correlation with inferior RNFL changes (r = 0.522; P<.008). Linear regression confirmed a strong relationship between the superior sectoral visual field indexes and the inferior RNFL. CONCLUSION: Scanning laser polarimetry was able to identify structural changes of the RNFL globally and in the inferior SLP sector with functional loss in NAION.

Adult↗

PubMed2006

Giant cell arteritis.

Giant cell arteritis (GCA) is an immune-mediated vasculitis, affecting medium- to large-sized arteries, in individuals over the age of 50 years. Visual loss is a frequent complication of GCA, and once it occurs it tends to be both permanent and profound. Although major advances have been made in recent years in genetics, molecular biology and the description of the vessel wall morphology, the aetiology and pathogenesis of GCA are still incompletely understood. Over the years there has been much debate over whether polymyalgia rheumatica and GCA are separate or linked entities. Recent investigations support that polymyalgia rheumatica and GCA are two different expressions of the same underlying vasculitic disorder. A single cause or aetiological agent has not as yet been identified. Except for the histopathology of the arterial wall, there are no laboratory findings specific for GCA, and no particular signs or symptoms specific for the diagnosis. GCA typically causes vasculitis of the extracranial branches of the aorta and spares intracranial vessels. Transmural inflammation of the arteries induces luminal occlusion through intimal hyperplasia. Clinical symptoms reflect end-organ ischaemia. Branches of the external and internal carotid arteries are particularly susceptible. Corticosteroids remain the only proven treatment for GCA, the regimen initially involving high doses followed by a slow taper. However, early detection and treatment with high-dose corticosteroids is effective in preventing visual deterioration in most patients.

Giant Cell Arteritis↗

PubMed2006

Glaucoma management trends in Australia and New Zealand.

BACKGROUND: To describe self-reported patterns of care for glaucoma of ophthalmologists in Australia and New Zealand and summarize current practice styles and patterns associated with glaucoma management. METHODS: A questionnaire of glaucoma management practices was mailed to all ophthalmologists registered with the Royal Australian and New Zealand College of Ophthalmologists in June 2003. The questionnaire assessed practice preferences for medical management, examination techniques and indications for surgery. The results were cross-tabulated by age, country and subspecialty training in glaucoma. RESULTS: Fifty-one per cent of 761 surveys were returned, 14% being from glaucoma specialists. New Zealand ophthalmologists proceeded to surgical management of glaucoma earlier than did their Australian colleagues. Australian ophthalmologists tended to use argon laser trabeculoplasty more frequently. Ninety-six per cent of ophthalmologists routinely use gonioscopy in diagnosing glaucoma. Disc drawings and recording cup:disc ratios were the most commonly used methods of documenting disc morphology; glaucoma specialists were more likely to use imaging technologies. SITA-Standard 24-2 was the most commonly used modality of perimetry, and was favoured by glaucoma specialists. CONCLUSIONS: This survey represents the first Australian and New Zealand effort to identify glaucoma management practices. Although a substantial consensus was found in most areas of treatment, a few areas showed diversity. The information gathered will enable ophthalmologists to compare their own practices with those of their colleagues. In addition, this survey provides a baseline allowing future trends in management to be determined.

Australia↗

PubMed2006

Glaucoma prescribing trends in Australia and New Zealand.

PURPOSE: To summarize current practice styles and patterns associated with glaucoma management in ophthalmologists of Australia and New Zealand as derived from a survey. METHOD: A questionnaire was sent to all Australian and New Zealand ophthalmologists, which anonymously assessed demographic characteristics and prescribing patterns for each major class of glaucoma medication. RESULTS: A total of 761 questionnaires were sent with a response rate of 51%. Of respondents 14% were glaucoma subspecialists. In 69%, the first-line drug-class of choice was a prostaglandin analogue. New Zealand ophthalmologists favoured beta-blockers as their first-line agent because of cost, government restrictions and familiarity. Most respondents stated "hypotensive efficacy" as the most important factor in class choice. Alpha-2-agonists, carbonic anhydrase inhibitors and miotics were considered second-line agents, because of side-effects and lack of hypotensive potency. CONCLUSIONS: The choice of first-line agent for the treatment of glaucoma differed between Australian and New Zealand ophthalmologists, in part as the result of government restriction of prostaglandin-class drugs. Practice patterns seen in Australasia parallel the current evidence base reported in peer-reviewed literature.

Antihypertensive Agents↗

PubMed2006

Correlation of the multifocal visual evoked potential and standard automated perimetry in compressive optic neuropathies.

PURPOSE: To evaluate the relationship between abnormalities detected by the multifocal visual-evoked potential (mfVEP) compared with those detected by static achromatic automated perimetry in patients with compressive optic neuropathy. METHODS: Fifteen patients of mean age 50.8 years, with known compressive optic neuropathy from chiasmal lesions, underwent monocular mfVEP and 24-2 SITA-standard Humphrey visual field (HVF; Carl Zeiss Meditec, Dublin CA) testing in each eye. Visual field spatial agreement and extent of involvement were analyzed by assigning a severity score to each quadrant, based on pattern deviation and amplitude deviation probability plots. RESULTS: HVF mean deviation (MD) was -6.54 +/- 7.43 dB (mean), and the mfVEP mean AccuMap Severity Index (ASI; ObjectiVision Pty. Ltd., Sydney, Australia) score was 81 +/- 74. MD and ASI correlated significantly (r = -0.55, P = 0.024). Although both mfVEP and HVF reported approximately the same proportion of visual fields as abnormal (70%, 21/30, and 87%, 26/30, respectively), 19% (5/26) with abnormal HVF were labeled normal or borderline by mfVEP. The agreement for field quadrants between instruments was 69% (kappa = 0.33). mfVEP severity scores for quadrants and hemifields were higher than scores for HVF in the same eyes. The superotemporal quadrant showed the strongest correlation between techniques (r = 0.73, P = 0.002). CONCLUSIONS: In the first study to compare mfVEP to HVF in patients with compressive optic neuropathy, there was good qualitative and quantitative agreement between tests, though findings were in only modest agreement in some areas. The injury caused by compressive optic neuropathy may be usefully identified by mfVEP. Improved methods of analysis may increase the diagnostic utility of the method.

Evoked Potentials, Visual↗

PubMed2006

Relationship between retinal nerve fiber layer and visual field sensitivity as measured by optical coherence tomography in chiasmal compression.

PURPOSE: To investigate the spatial relationship between retinal nerve fiber layer (RNFL) thickness measured with optical coherence tomography (OCT) and visual field sensitivity (VFS) measured by standard automated perimetry (SAP) in chiasmal compression. METHODS: Twenty-six patients with chiasmal compression were enrolled. RNFL thickness was measured with the StratusOCT and VFS with SAP (Humphrey Field Analyzer; both from Carl Zeiss Meditec, Dublin, CA). Relationships between RNFL thickness (in clock hours, hemifields, and sectors) and VFS (zones were divided into hemifields, quadrants, and sectors based on a validated visual field map) expressed in a decibel scale and 1/lambert (L) were evaluated by linear and nonlinear regression. Coefficients of determination (R(2)) were calculated by using a multivariate model. RESULTS: Average RNFL thickness correlated strongly with pattern standard deviation (PSD; R = 0.622) and mean deviation (MD; R = 0.413). The four strongest correlations were between the 8 o'clock OCT position (temporal disc), with the temporal hemifield (R = -0.813), the superotemporal quadrant (R = -0.847), the inferotemporal quadrant (R = -0.855), and the field sector representing the papillomacular bundle (R = -0.809). Coefficients of determination improved significantly in all sectors when time since surgery was included in the regression model-most notably, average thickness and 1/L (R(2) = 0.35-0.49), the decibels (R(2) = 0.31-0.47), and the temporal sector (R(2) = 0.44-0.57). CONCLUSIONS: This is the first study to compare the structure-function correlation of RNFL measured by OCT with SAP in patients with chiasmal compression. RNFL is topographically related globally and sectorally to decreased SAP, with the temporal sectors showing the strongest correlations. The correlation between RNFL and VFS strengthens as the time from surgical intervention increases.

Adolescent↗

PubMed2004

Analysis of New Zealand's research productivity in ophthalmology and vision science: 1993-2002.

AIM: To assess New Zealand's research productivity in the area of ophthalmology and vision science over the decade 1993-2002. METHODS: New Zealand-based researchers involved in ophthalmology or vision science research, including ophthalmologists, optometrists and vision scientists were identified via professional colleges, universities and electronic databases. Peer-reviewed publications by these authors were identified by both searching electronic databases (MEDLINE/Pubmed) and personal communication with individual researchers. RESULTS: Eighty-five New Zealand-based researchers involved in ophthalmology or vision science research published 446 articles in 84 scientific journals during the 10-year period. The cohort consisted of 59 ophthalmologists and 26 other researchers based in a diverse range of ophthalmology, optometry and university departments. Significant collaboration was observed between groups within New Zealand and with international institutions. Comparing ophthalmologists and 'other' researchers, ophthalmologists produced 69% of all ophthalmology and vision science research publications and those classified as 'active ophthalmologist researchers' published an average of 11 (range 5-55) papers each during this decade, compared to eight (range 5-25) for the group 'other active researchers'. This was also reflected in the high productivity rate by ophthalmologists of 277 publications per 1000. Publications were identified in a wide range of journals with the majority in top 20-ranked ophthalmology journals. The trend over the decade highlighted an increase in number of scientific publications, from 43 per annum in 1993, to 68 per annum in 2002. CONCLUSIONS: Despite a relatively small and geographically isolated population, New Zealand ophthalmology and vision science research is highly active and collaborative, with significantly increased research productivity during the period 1993-2002. The present study is the first to document these trends and provides strong evidence to justify continued support for ophthalmology and vision science research in New Zealand.

Bibliometrics↗