Biomedical subjects

Lyne Racette

Publications and source records attributed to Lyne Racette.

6 recordsLinked to original sources

PubMed2006

Agreement and repeatability for standard automated perimetry and confocal scanning laser ophthalmoscopy in the diagnostic innovations in glaucoma study.

PURPOSE: To assess agreement between structural and functional testing in classifying eyes as normal or abnormal and their repeatability on two consecutive visits by means of standard automated perimetry (SAP) and confocal scanning laser ophthalmoscopy. DESIGN: Analysis of selected data obtained from a prospective longitudinal observational cohort study, the Diagnostic Innovations in Glaucoma Study. METHODS: One hundred fifty-one participants with a SAP and a Heidelberg Retina Tomograph (HRT) test within a three-month window at two visits within 15 months were included. Eyes were classified by SAP and HRT at each visit. Agreement and repeatability were assessed by kappa statistics. RESULTS: At visit 1, 33 (22%) of 151 eyes had only SAP defects, 11 (7%) eyes had only HRT defects, and 35 (23%) eyes had both SAP and HRT defects. Seventy-two eyes (48%) were classified as normal by both tests. Similar results were obtained for visit 2. The agreement between SAP and HRT in classifying eyes was 70% (kappa = 0.393) at visit one and 68% (kappa = 0.363) at visit 2. Repeatability of classification by SAP alone, HRT alone, and both SAP and HRT between visits 1 and 2 was 84% (kappa = 0.693), 89% (kappa = 0.752), and 90% (kappa = 0.723), respectively. CONCLUSIONS: Agreement between SAP and HRT was only fair at both visits. Repeatability across visits was substantial for SAP alone, HRT alone, and for the combination of SAP and HRT. These results suggest that detection of particular features of glaucomatous damage depends on the technique used. Structural and functional tests appear complementary, and both should be used for early detection of glaucoma.

Female↗

PubMed2006

Identifying glaucomatous vision loss with visual-function-specific perimetry in the diagnostic innovations in glaucoma study.

PURPOSE: To compare the diagnostic results of four perimetric tests and to identify useful parameters from each for determining abnormality. METHODS: One hundred eleven eyes with glaucomatous optic neuropathy (GON), 31 with progressive optic neuropathy (PGON) 53 with ocular hypertension, and 51 with no disease were included (N = 246). Visual field results were not used to classify the eyes. Short-wavelength automated perimetry (SWAP), frequency-doubling technology perimetry (FDT), high-pass resolution perimetry (HPRP), and standard automated perimetry (SAP) were performed. Receiver operating characteristic (ROC) curves were used to compute the areas under the curves (AUC) and sensitivity levels at given specificities for a variety of abnormality criteria. The agreement among tests for abnormality, location, and extent of visual field deficit were assessed. RESULTS: AUC analysis: When the normal group was compared with the GON group, the FDT pattern SD (PSD) area was larger than the HPRP PSD (P = 0.020), and the FDT area of total deviation (TD) <5% was larger than the HPRP mean deviation (MD; P = 0.004). When the normal group was compared with the PGON group, the FDT area of pattern deviation (PD) <5% was larger than the SWAP PSD (P = 0.020). A difference from previous work was that AUCs for PSD or the best SAP were not significantly poorer than those in the function-specific tests. At set specificities, FDT yielded higher sensitivities than all other tests for all parameters. The agreement among tests for abnormality was fair to moderate (kappa = 247-0.563). When loss was present on more than one test, the quadrant of the visual field affected was the same in 95% (79/83) of eyes. The number of eyes identified and number of abnormal quadrants increased across groups with increasing certainty of glaucoma. CONCLUSIONS: At equal specificity, no single perimetric test was always affected, whereas others remained normal. Several parameters at suggested criterion values provided good sensitivity and specificity. FDT showed the highest sensitivity overall, with SAP performing better than in prior reports. Of note, the same area of the retina was identified as damaged in all tests.

Adult↗

PubMed2005

Differences in visual function and optic nerve structure between healthy eyes of blacks and whites.

OBJECTIVE: To investigate differences in visual function, optic disc topography, and retinal nerve fiber layer (RNFL) thickness between healthy eyes of blacks and whites. METHODS: Visual function was assessed in healthy eyes of 50 blacks and 50 whites using standard automated perimetry, short-wavelength automated perimetry, and frequency doubling technology perimetry. Optic disc topography and RNFL thickness were measured using the Heidelberg Retina Tomograph and the optical coherence tomograph. RESULTS: Mean standard automated perimetry mean deviations were within the normal range for both groups. Blacks had worse mean deviation values than whites using frequency doubling technology perimetry (mean +/- SD, -1.8 +/- 3.2 dB vs -0.1 +/- 2.4 dB), blacks had larger optic disc areas than whites using the Heidelberg Retina Tomograph (mean +/- SD, 2.1 +/- 0.4 mm2 vs 1.7 +/- 0.4 mm2), the RNFL of blacks was thicker than that of whites by 16.91 microm superiorly and 10.10 microm inferiorly using optical coherence tomography, and blacks had slightly higher intraocular pressures than whites (mean +/- SD, 16.5 +/- 2.5 mm Hg vs 15.2 +/- 3.2 mm Hg) and thinner central corneas (mean +/- SD, 540.5 +/- 43.2 microm vs 560.9 +/- 35.5 microm). No racial differences were found in mean RNFL thickness, pattern standard deviation on all tests, or any of the short-wavelength automated perimetry variables. CONCLUSIONS: Minimal racial differences in visual function were found, but race significantly affected optic disc topography and superior and inferior RNFL thickness measurements in healthy eyes. The racial differences observed for intraocular pressure could theoretically increase after correcting for central corneal thickness. Prospective studies are needed to further investigate these findings.

Anthropometry↗

PubMed2005

The impact of visual field loss on driving performance: evidence from on-road driving assessments.

PURPOSE: The purpose of this study was to investigate the relationship between visual field loss and driving performance as determined by on-road driving assessments. METHODS: We reviewed the files of 1350 patients enrolled in a rehabilitation program at the Bloorview MacMillan Rehabilitation Centre, Toronto, Canada. We identified 131 patients with visual field loss who had undergone an on-road driving assessment. These patients had a primary diagnosis of visual impairment or a primary diagnosis of cerebral vascular accident (CVA) with a secondary diagnosis of visual impairment. None of these patients had documentation of neglect, substantial motor or cognitive deficits. We report the data obtained from 13 hemianopics, 7 quadrantanopics, 25 patients with monocular vision, 10 patients with moderate peripheral losses (<135 degrees of horizontal visual field measured at the midline), and 76 patients with mild peripheral losses (between 135 degrees and 186 degrees of horizontal visual field). The on-road assessment consisted of driving in the area surrounding the rehabilitation center, and the outcome was based on performance on a number of tasks commonly encountered in daily driving. For the purposes of this study, the assessment outcomes were classified as safe, unknown, or unsafe. RESULTS: Overall, the extent of visual field loss did not have a significant impact on driving performance (chi2 = 4.37, p = 0.358). However, hemianopia tended to have a worse impact on driving performance than quadrantanopia with a marginally significant result (chi2 = 3.33, p = 0.068). Overall, the location of the visual loss was not significantly related to driving fitness (chi2 = 1.05, p = 0.30). However, localized defects in the left hemifield (chi2 = 9.561, p = 0.002) and diffuse visual loss in the right hemifield (chi2 = 10.395, p = 0.001) seemed to be associated with driving impairments. A large proportion of monocular drivers were safe drivers and the location of their deficit had no significant impact. CONCLUSIONS: Although the extent of visual field defects appears to be related to driving performance as determined by an on-road driving assessment, large individual differences were observed. This highlights the need for individualized on-road assessments for patients with visual field defects.

Automobile Driving↗

PubMed2003

Short-wavelength automated perimetry.

Short-wavelength automated perimetry (SWAP) is a visual field test designed to assess the short-wavelength sensitive color system by isolating the blue-yellow pathway. SWAP is a powerful clinical tool able to detect visual field deficits 3 to 5 years before standard automated perimetry (white-on-white) in most glaucoma patients, and progression of visual field defects up to 3 years earlier. SWAP deficits are predictive of the onset and location of future visual field loss, and they correlate well with structural damage associated with glaucoma. The main disadvantage of SWAP remains the longer testing time required. In the clinic, it is recommended that SWAP be performed on patients who are at higher risk for glaucoma. Although SWAP was originally developed to detect visual loss in glaucoma patients, it is also useful for patients with diabetic retinopathy and maculopathy, optic neuropathies, vision loss associated with HIV, migraine, and multiple sclerosis. More sensitive psychophysical tests of visual function, such as SWAP, can significantly shorten clinical trials and aid in the validation of new therapeutic approaches.

Color Perception↗

PubMedDate not supplied

Primary open-angle glaucoma in blacks: a review.

Glaucoma is one of the leading causes of blindness worldwide. Primary open-angle glaucoma (POAG) is the most prevalent form of glaucoma and has a particularly devastating impact in blacks. In the black American population, POAG prevalence is estimated to be six times as high in certain age groups compared to whites. POAG is more likely to result in irreversible blindness, appears approximately 10 years earlier and progresses more rapidly in blacks than in whites. Racial differences in optic disk parameters have been reported and show that blacks have larger optic disks than whites. This finding is robust and may account for the reported differences in other optic disk parameters. The existence of racial differences in intraocular pressure remains to be demonstrated, as conflicting findings are reported in the literature. Intraocular pressure may actually be underestimated in blacks, perhaps because they have thinner corneas. The prevalence of diabetes and hypertension is higher in blacks than in whites, and although no causal relationship has been established between POAG and each of these systemic diseases, some reports suggest that they often occur together, perhaps through an indirect relationship with intraocular pressure. Compounding the problem, there is evidence that blacks are less responsive to both drug and surgical treatment for POAG. Finally, they often have reduced accessibility to treatment and are less aware of the risks of having POAG. This article provides a comprehensive review of the current knowledge pertaining to POAG in blacks.

Black People↗