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Biomedical subjects

C A Harper

Publications and source records attributed to C A Harper.

At least 19 recordsLinked to original sources
PubMed2006

Diagnostic thresholds for diabetes: the association of retinopathy and albuminuria with glycaemia.

AIM: We examined the association of fasting plasma glucose (FPG), 2-h plasma glucose (2hPG) and HbA1c with retinopathy and microalbuminuria using both deciles of glycaemia and change point models, to validate current diagnostic criteria for diabetes and to identify therapeutic thresholds for glycaemic control. METHODS: The Australian Diabetes Obesity and Lifestyle study (AusDiab), conducted in 1999-2000, included adults aged > or =25 years from 42 randomly selected areas of Australia. Retinopathy and albuminuria were assessed in participants identified as having diabetes (based on self report and oral glucose tolerance test), impaired fasting glucose, impaired glucose tolerance and in a random sample with normal glucose tolerance. Data were available for 2,182 participants with retinal photographs and 2,389 with urinary albumin/creatinine results. RESULTS: The prevalence of retinopathy in the first 8 deciles of FPG and HbA1c and the first 9 deciles of 2hPG were 7.2, 6.6, and 6.3%, respectively and showed no variation with increasing glucose or HbA1c. Above these levels, the prevalence rose markedly to 18.6% in the top 2 deciles of FPG, 21.3% in the top 2 deciles of HbA1c and 10.9% in the top decile of 2hPG. The thresholds for increasing prevalence of retinopathy were 7.1 mmol/l for FPG, 6.1% for HbA1c and 13.1 mmol/l for 2hPG. The prevalence of microalbuminuria rose gradually across deciles of each glycaemic measure. Thresholds were less clear than for retinopathy, but were seen at a FPG of 7.2 mmol/l and HbA1c of 6.1%, with no evidence of a threshold effect for 2hPG. CONCLUSIONS: The prevalence of retinopathy rose dramatically in the highest deciles of each glycaemic measure, while for microalbuminuria the increase of prevalence was more gradual. The FPG values corresponded well with the WHO diagnostic cut-point for diabetes, however the 2hPG value did not. HbA1c thresholds were similar for both retinopathy and microalbuminuria and compared well to values shown in other studies. These results support current targets for FPG and HbA1c in preventing microvascular complications.

Aged↗
PubMed2006

Comparative study of the polaroid and digital non-mydriatic cameras in the detection of referrable diabetic retinopathy in Australia.

AIM: To show that the non-mydriatic retinal camera (NMRC) using polaroid film is as effective as the NMRC using digital imaging in detecting referrable retinopathy. METHODS: A series of patients with diabetes attending the eye out-patients department at the Royal Victorian Eye and Ear Hospital had single-field non-mydriatic fundus photographs taken using first a digital and then a polaroid camera. Dilated 30 degrees seven-field stereo fundus photographs were then taken of each eye as the gold standard. The photographs were graded in a masked fashion. Retinopathy levels were defined using the simplified Wisconsin Grading system. We used the kappa statistics for inter-reader and intrareader agreement and the generalized linear model to derive the odds ratio. RESULTS: There were 196 participants giving 325 undilated retinal photographs. Of these participants 111 (57%) were males. The mean age of the patients was 68.8 years. There were 298 eyes with all three sets of photographs from 154 patients. The digital NMRC had a sensitivity of 86.2%[95% confidence interval (CI) 65.8, 95.3], whilst the polaroid NMRC had a sensitivity of 84.1% (95% CI 65.5, 93.7). The specificities of the two cameras were identical at 71.2% (95% CI 58.8, 81.1). There was no difference in the ability of the polaroid and digital camera to detect referrable retinopathy (odds ratio 1.06, 95% CI 0.80, 1.40, P = 0.68). CONCLUSION: This study suggests that non-mydriatic retinal photography using polaroid film is as effective as digital imaging in the detection of referrable retinopathy in countries such as the USA and Australia or others that use the same criterion for referral.

Aged↗
PubMed2005

Rates of diabetes mellitus-related complications in a contemporary adolescent cohort.

BACKGROUND: Ten years after the Diabetes Control and Complications Trial there is a paucity of data as to what are current rates of diabetes-related complications in adolescence. OBJECTIVE: To assess the incidence of diabetes-related complications in a contemporary cohort of adolescents with type 1 diabetes mellitus. DESIGN: Retrospective cross-sectional survey. PATIENTS: Adolescents aged >10 years with type 1 diabetes mellitus for >5 years from the Royal Children's Hospital, Melbourne Diabetes Clinic. RESULTS: 382 patients were studied (191 male). The mean HbA1c for males was 8.72% and for females was 8.80%. The rates of hypothyroidism and hypercholesterolaemia were 1.5% and 22% respectively. Twenty-five patients (8%) had intermittent microalbuminuria and six (2%) had persistent microalbuminuria. Only one patient had macroalbuminuria (0.3%). Only two patients (0.7%) with mild non-were diagnosed proliferative diabetic retinopathy. Coeliac disease was diagnosed in 6% of patients. CONCLUSIONS: In this representative and contemporary cohort of diabetic adolescents the incidence of microvascular diabetes-related complications is quite low.

Adolescent↗
PubMed2000

Ocular-central nervous system lymphoma mimicking posterior scleritis with exudative retinal detachment.

OBJECTIVE: We describe an unusual ocular presentation of ocular-central nervous system lymphoma in a young patient. DESIGN: Interventional case report and literature review. METHODS: A previously well 24-year-old white woman presented with left eye pain and reduced vision. Episcleral injection, globe tenderness, an afferent pupil defect, and exudative retinal detachment were present. Computed tomographic scan of the head and orbits demonstrated scleral thickening, retinal detachment, and no other abnormality. A provisional diagnosis of posterior scleritis with exudative retinal detachment was made. Investigation for underlying connective tissue diseases was negative. There was an initial prompt response to corticosteroid therapy. The patient's symptoms and signs then recurred, and a left third cranial nerve palsy developed. Systemic investigations including lumbar puncture ultimately led to the diagnosis of primary T-cell central nervous system (CNS) lymphoma. Serologic tests for human immunodeficiency virus were negative. MAIN OUTCOME MEASURES AND RESULTS: The patient underwent orbital and cranial irradiation and intrathecal and systemic chemotherapy. Despite an initial response to treatment, she returned with a recurrence of the lymphoma in the anterior segment of the left eye. Her systemic disease progressed rapidly, and she died shortly thereafter. CONCLUSIONS: This patient's young age and initial presentation mimicking posterior scleritis with unilateral exudative retinal detachment, without evidence of vitreous involvement, are highly unusual for ocular involvement in primary CNS lymphoma. A review of the literature highlights the atypical nature of this presentation.

Adult↗
PubMed2000

Examination compliance and screening for diabetic retinopathy: a 2-year follow-up study.

Early detection and timely treatment of diabetic retinopathy can preserve vision, yet many people with diabetes do not have their eyes examined regularly. The purpose of this study was to examine eye care practices of people with diabetes who had not previously accessed eye care services on a regular basis. Screening with non-mydriatic retinal photography for diabetic retinopathy was initiated in 1996, and targeted people with diabetes who did not access eye care services on a regular basis. Each test area was revisited 2 years after the initial screening. Patients that did not attend the biennial screening were followed up by mail survey. Although none of the participants in this study had been previously accessing eye care services on a regular basis, 87% did so after attending the screening. These results indicate that mobile screening with non-mydriatic photography, as an adjunct to current eye care services, has the potential to increase examination compliance for diabetic retinopathy and to achieve sustained behaviour change.

Diabetic Retinopathy↗
PubMed2000

Recruitment methods for community-based screening for diabetic retinopathy.

Regular screening of all people with diabetes is the most efficient and cost-effective way to detect early stages of diabetic retinopathy so that laser treatment can be performed at the optimal time. A major aim of the Program for the Early Detection of Diabetic Retinopathy was to increase compliance with guidelines for screening for diabetic retinopathy. This community-based screening program used non-mydriatic retinal photography and was initiated in four areas of Victoria, Australia from 1996-1998. Recruitment strategies included targeted mail-outs, provision of the program brochure in English and the main languages spoken in the areas and media promotion in ethnic newspapers and on ethnic radio stations. In Victoria, only 55% of the population with diabetes currently access eye care services at the recommended intervals. This program was able to increase compliance with guidelines to 70% among people with diabetes that had not had a recent eye examination. A total of 1,197 people with diabetes were screened for diabetic retinopathy. Of the 1,197 people who were screened, 620 (15% of the estimated number of people with diabetes) had not had their eyes examined in the past two years. This pilot study identified strategies to encourage people with diabetes to have their eyes examined at the recommended intervals.

Age Distribution↗
PubMed1999

Baseline ophthalmic findings in the vitamin E, cataract and age-related maculopathy (VECAT) study.

PURPOSE: To describe the methodology of eye examination and the baseline eye characteristics of the Vitamin E, Cataract and Age-Related Maculopathy (VECAT) study participants. METHODS: A sample of volunteers from an urban area of Melbourne, Australia, were recruited to participate in a randomized, controlled trial investigating the effect of vitamin E on the development of cataract and age-related maculopathy Standardized eye examinations involved clinical assessment, which included Wilmer grading of the lens, digital photography of the lens with Nidek EAS-1000 lens camera and stereo photography of the macular area with the Nidek 3-DX fundus camera. All cases of ophthalmic findings were determined on the basis of pathology in the worse eye. RESULTS: Most eyes were free from abnormalities. The most frequent findings were cataract and age-related macular changes. Nuclear cataract (nuclear opacity grade >2) was present in 4.5%, cortical cataract (cortical opacity grade >2) in 14.3% and posterior subcapsular cataract in 3.0% of participants; in addition, coronary cataract was observed in 13.6%. Soft drusen larger than 125 pm were found in 11.4%, retinal pigment epithelium changes in 9.5%, epiretinal membrane in 6.6% and age-related macular degeneration in 0.5% of participants. SUMMARY: Due to the selection criteria, the majority of participants had clear or minor lens changes and/or minor retinal age-related changes. Precise instrumental documentation will allow an accurate assessment of the incidence and dynamics of these changes throughout 4 years of observation.

Aged↗
PubMed1999

The VECAT study: methodology and statistical power for measurement of age-related macular features. Vitamin E, Cataract, and Age-related Maculopathy Study.

PURPOSES: (1) To develop the methodology for the grading of macular one-frame stereoslides and to assess the reliability of the system. (2) To determine the prevalence of soft drusen (> 63 microm) and pigment abnormalities synonymous with age-related maculopathy (ARM) at baseline, in a clinical trial of volunteers aged between 55 and 80 years of age. (3) To ascertain the power of the study to detect the 4-year incidence and progression of ARM in vitamin E versus placebo treated participants, given the baseline prevalence. METHODS: The 1204 participants enrolled in the Vitamin E, Cataract, and Age-related Maculopathy Study (VECAT) had colour stereoslides of their fundus taken using the Nidek 3-DX mydriatic fundus camera. The stereoslides were graded by two masked graders according to the "International Classification System for ARM and AMD". Assessment of inter- and intra-observer reliability was carried out on a regular basis on 15% of randomly selected slides. Anticipated rates of incidence and progression were based on results reported by the Beaver Dam Eye Study and the Chesapeake Bay Waterman Study. Power estimations were determined using the "nQuery Advisor" software program. Analyses were carried out on the worse affected eye. RESULTS: Inter-observer reliability was moderate to substantial (Kappa 0.5-0.88) whilst intra-observer agreement was high (0.6-1.0). The prevalence of any soft drusen was 32%. Significant associations were found between soft large indistinct drusen, hypopigmentation, hyperpigmentation and age (p = 0.0001, 0.024 and 0.0001, respectively). The study has at least 87% power to detect an odds ratio equal to two for the progression of soft distinct, soft indistinct, hyperpigmentation and hypopigmentation. CONCLUSIONS: The VECAT study methodology appears to be highly reliable and to have sufficient power to detect the differences in the four-year progression of soft distinct and indistinct drusen and pigment abnormalities between the treatment groups.

Aged↗
PubMed1998

Screening for diabetic retinopathy using a non-mydriatic retinal camera in rural Victoria.

PURPOSE: To develop a screening programme for the early detection of diabetic retinopathy using non-mydriatic retinal photography. METHODS: A community based screening service was offered to all people with known diabetes mellitus in selected townships in the LaTrobe and Goulburn Valleys in Victoria. At the local examination centre, basic sociodemographic information was collected as well as details of previous use of eye care services for the early detection of diabetic retinopathy. The examination included visual acuity (VA), glycosylated haemoglobin level and Polaroid photographs of each fundus using a Canon CR5-45NM non-mydriatic retinal camera (Canon, Tochigiken, Japan). Dilating drops were not used. Photographs were subsequently reviewed and letters were sent to all participants (with copies to their general practitioners) with recommendations for appropriate follow up. RESULTS: A total of 1177 people with diabetes attended the screening service, which is estimated to be 40% of the total population with known diabetes in the study area. The mean age was 65 years (range 20-94 years); 559 (48%) people reported not having a dilated fundus examination within the past 2 years; 345 (29%) people had never had a dilated fundus examination. Of the 2354 eyes, 2126 (90%) of the photographs were gradable. A total of 704 people (60%) had normal VA and no evidence of diabetic retinopathy, 209 people (18%) had diabetic retinopathy, 101 people (9%) had evidence of other fundus pathology, 42 people (3%) had reduced acuity (< 6/18) in one or both eyes (with no fundus pathology evident) and 121 people (10%) had ungradable photographs in one or both eyes. CONCLUSIONS: The present study demonstrates the usefulness of a screening programme with non-mydriatic retinal photography as an adjunct to current eye care services for the early detection of diabetic retinopathy.

Adult↗
PubMed1996

Diabetic retinopathy: examination practices and referral patterns of general practitioners.

OBJECTIVE: To investigate general practitioners' (GPs') examination and referral practices for diabetic retinopathy. METHODS: A questionnaire survey of a random stratified sample of 500 Victorian GPs. RESULTS: The response rate was 88%. 53% of GPs examined none or less than half of their patients with diabetes for diabetic retinopathy. Those who did examine for retinopathy rarely performed funduscopy through a dilated pupil and 65% reported that they never did. Only 37% had dilating drops in their surgery. Only 45% often or always tested visual acuity. 88% often or always referred patients at the recommended frequency to an ophthalmologist. CONCLUSIONS: Although most GPs do not perform dilated fundus examinations, they report referring their patients with diabetes for assessment by an ophthalmologist at an early stage to prevent vision loss. Referral chain breakdown may explain the discrepancy between GPs' reported referral rates and the lower rates of ophthalmic examination reported in the Melbourne Visual Impairment Project.

Clinical Competence↗
PubMed1995

Early detection of diabetic retinopathy.

Diabetic retinopathy remains a leading cause of blindness in Australia. Most cases can be prevented by timely laser photocoagulation and this requires early detection of asymptomatic retinopathy. The Australian Diabetes Society recommends regular retinal examinations through dilated pupils, either at diagnosis of diabetes (onset over 30 years), or five years after diagnosis (onset under 30 years). Examination should be repeated at least every two years, or more frequently in the presence of visual symptoms, pregnancy or other risk factors. Diabetic patients and primary care physicians should be better informed about the effectiveness of timely treatment of diabetic retinopathy and the need for regular eye examinations, either by general practitioners or through referral to ophthalmologists.

Adult↗
PubMed1994

Acute zonal occult outer retinopathy (AZOOR) associated with multifocal choroidopathy.

Acute zonal occult outer retinopathy (AZOOR) may be precipitated by various retinal disorders and is characterised by rapid loss of visual field which cannot be explained by the ophthalmoscopic changes consequent upon the initiating disease. The electroretinogram is abnormal, indicating that the field loss is due to retinal dysfunction. The phenomenon was first recognised in the multiple evanescent white dot syndrome (MEWDS) as the enlarged blind spot syndrome. It was subsequently described with multifocal inner choroidopathy and acute macular neuropathy (AMN). We have identified 7 patients who presented with widespread visual loss associated with multifocal inner choroidopathy in whom functional loss was documented with electroretinography and automated visual field testing. All patients were young, myopic, and otherwise healthy women. Initial photopsia was noted by 4 patients. Fundus findings included scattered small partially pigmented yellowish lesions resembling those in multifocal inner choroidopathy or pseudo presumed ocular histoplasmosis syndrome, disc swelling, vitritis, and secondary choroidal neovascularisation. Two patients had bilateral involvement. All patients had an enlargement of the blind spot, and widespread visual field loss which was not explained by fundus changes. All had an abnormal electroretinogram suggesting widespread retinal disease. In AZOOR retinal dysfunction occurs without corresponding visible retinal lesions. This disorder appears to be precipitated by several conditions, although the causal relationship between the initiating event and the widespread functional loss is unknown.

Acute Disease↗
PubMed1993

The aetiology of ocular toxoplasmosis in Melbourne.

The biological mothers of 23 patients presenting with acute chorioretinal toxoplasmosis had sera screened for the presence of antibodies to Toxoplasma gondii. Twenty-two of the mothers (96%) had positive serology and one (4%) had negative serology. This is consistent with the hypothesis that most cases of ocular toxoplasmosis are congenital in origin, but indicates that some cases are due to acquired toxoplasmosis.

Adolescent↗
PubMed1993

Perfluorocarbon liquid in traumatic vitreous hemorrhage and retinal detachment.

Patients with penetrating ocular trauma also may have severe vitreous hemorrhage and associated retinal detachment. Removing the hemorrhage and repairing the detachment can be a difficult surgical problem. Besides the limited surgical view due to the hemorrhage, an incomplete separation of the posterior hyaloid membrane can allow the detached retina to be drawn toward the port of the vitrectomy instrument, producing an inadvertent retinal tear. We have used perfluoroperhydrophenanthrene (Vitreon) to manage three cases of penetrating ocular trauma with concurrent retinal detachment and a partial vitreous detachment, either at the time of surgery or as noted ultrasonographically. The perfluorocarbon liquid helped to separate the partially detached posterior hyaloid membrane and flatten the detached retina. This maneuver simplified removal of the vitreous hemorrhage and management of the retinal detachment.

Adult↗