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Disc Photography (disc + photography)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

The nerve fibre layer symmetry test: computerized evaluation of human retinal nerve fibre layer thickness as measured by optical coherence tomography

ACTA OPHTHALMOLOGICA, Issue 4 2004
Jesper Leth Hougaard
Abstract. Purpose:,To present and test a new interpretative concept, the nerve fibre layer symmetry test (NST), for computerized evaluation of retinal nerve fibre layer thickness (RNFLT) as measured by optical coherence tomography (OCT) in glaucoma. Methods:,The NST concept was constructed and tested in a pilot study. A total of 32 healthy and 40 age-matched glaucomatous eyes were included and examined by OCT, computerized perimetry, RNFL/disc photography, tonometry and a general ophthalmologic examination. Results:,The observed NST sensitivity and specificity were high, at 38/40 eyes (95%) and 32/32 eyes (100%), respectively, and 40/40 eyes (100%), and 31/32 eyes (97%), respectively, when correcting the OCT RNFLT measurement for the influence of variability in image signal/quality. The NST sensitivity was 8,10% higher than the single most sensitive traditional OCT RNFLT parameter; this difference was not statistically significant in this small sample. Conclusion:,The NST showed high specificity and sensitivity for detection of RNFLT attenuation indicating early to severe glaucoma. Although promising, the NST needs to be further developed and validated in larger study samples and in patients with various stages of glaucomatous damage. [source]

Relative afferent pupillary defect in glaucoma: a pupillometric study

ACTA OPHTHALMOLOGICA, Issue 5 2007
Lada Kalaboukhova
Abstract. Purpose:, To study the presence of relative afferent pupillary defect (RAPD) in patients with glaucoma with the help of a custom-built pupillometer. Methods:, Sixty-five participants were recruited (32 with open-angle glaucoma and 33 healthy subjects). All underwent standard clinical examination including perimetry and optic disc photography. Pupillary light reflexes were examined with a custom-built pupillometer. Three video sequences were recorded for each subject. Alternating light stimulation with a duration of 0.5 seconds was used, followed by a 1 second pause. Mean values of pupil area ratio (PAR), pupil contraction velocity ratio (PCVR), and pupil dilation velocity ratio (PDVR) were calculated. Receiver operating characteristic (ROC) curves were constructed for each of the three parameters. Intra-individual variability was estimated. Results:, PAR and PDVR differed significantly between the group with glaucoma and the control group (P < 0.0001). PAR was more sensitive for glaucoma detection than the other pupillometric parameters (PCVR and PDVR). The area under the receiver operating characteristic curve was largest for PAR. At a fixed specificity of 90%, sensitivity for PAR was 86.7%. Conclusion:, Measuring RAPD with infrared computerized pupillometry can detect optic neuropathy in glaucoma with high sensitivity and specificity. The method is fast and objective. Pupil area amplitude measurements were superior to pupil velocity measurements for the detection of RAPD in glaucoma [source]

Frequency doubling technology and high-pass resolution perimetry in glaucoma and ocular hypertension

ACTA OPHTHALMOLOGICA, Issue 3 2003
Lada Kalaboukhova
Abstract. Purpose:, To study the correlation between frequency doubling technology perimetry (FDT) and high-pass resolution perimetry (HRP) in eyes with primary open-angle glaucoma, suspect glaucoma, ocular hypertension, and in normal eyes. Patients and Methods:, Ninety-four patients (162 eyes) were studied. Visual fields were assessed by HRP, FDT screening C-20,5 and FDT threshold C-20 programs. In eyes with a discrepancy between the test results, a comprehensive clinical examination was performed, including optic disc photography and Heidelberg retinal tomography (HRT). Results:, There was a strong correlation between HRP global deviation and the FDT mean deviation (for FDT threshold C-20 test), and between HRP score and FDT score (for FDT screening C-20,5 ). The correlation coefficients were r = ,0.83 and r = 0.77, respectively. In all, 75 eyes (46.3%) had normal HRP and FDT screening results, while 67 eyes (41.4%) showed abnormal results in both tests. In 12 eyes (7.4%) HRP was within normal limits while FDT screening was abnormal. Seven of these eyes were judged to have glaucoma; three of them had converted from ocular hypertension to glaucoma. In eight eyes (4.9%) HRP was abnormal while FDT screening was normal. Three of these were judged to have glaucoma. Thus, the sensitivity and specificity of the FDT screening test for the detection of glaucoma were 91.7% and 87.8%, respectively. Conclusion:, There was a strong correlation between FDT threshold C-20, FDT screening C-20,5 and HRP test results. Frequency doubling technology perimetry C-20,5 represents a good screening test for the detection of optic nerve damage in open-angle glaucoma. [source]

Optic nerve head parameters of an indigenous population living within Central Australia

CLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 9 2006
John A Landers MBBS MPH
Abstract Purpose:, Clinical examination of the optic disc is an essential element in the assessment of its health. Previous work has described normal optic disc appearance among different races. No such description of optic discs exists for indigenous Australians, who are at low risk of developing glaucoma. This study was designed to evaluate optic disc parameters of indigenous Australians. Methods: A sample of 208 indigenous Australians were recruited as they presented to remote clinics in Central Australia. Each subject underwent optic disc photography using a Topcon TRC-NW100 digital fundus camera. Optic discs were measured and analysed with Topcon ImageNet 2000 software. Results: Among other parameters, mean vertical disc diameter and disc area were 2.13 ± 0.21 mm (mean ± SD) and 3.13 ± 0.57 mm2, respectively, for right eyes and 2.14 ± 0.21 mm and 3.16 ± 0.58 mm2 for left eyes. When compared with published studies, these parameters were significantly larger than Caucasians, but similar to African individuals. Conclusion:, Our results suggest that indigenous Australians have optic discs that are larger than those of Caucasians, but similar to those of Africans who are considered to at a greater risk of glaucoma. Factors other than optic disc area are likely to underlie the higher prevalence of primary open angle glaucoma among African individuals. [source]