Clinical Viability Study of Preattentive Visual Search Glaucoma

Background/Aim: Previous research has shown that several clinical conditions cause increased pre-attentive visual search (PAVS) times, implying reduced parallel search capabilities in glaucoma, DLB dementia and Parkinson’s disease. The purpose of the research reported here was two-fold • To examine for the first time the effect of a number of variables on PAVS performance including optical blur, age, retinal eccentricity and perceptual learning. Such investigations are designed to elucidate the nature of best clinical practise and to determine whether the test remains viable in the presence of such potentially confounding variables. • To analyse the efficiency of PAVS in cases of established glaucoma: glaucoma suspects and age –matched normals. Such an investigation is designed to determine the differential diagnostic capacity of the current test and to provide diagnostic cut-off performance indices to facilitate clinical categorisation of patients Methods: Suitably configured flicker, motion displacement and orientation pop-out stimuli were presented to subjects on a computer monitor. The subjects’ task was to accurately locate the pop-out target from among 120 distractors on either left or right of the monitor as rapidly as possible. PAVS performance was determined through analysis of the speed of accurate target location and its relation to the individuals’ complex (non-preattentive) reaction time. Results: The current test remains largely resistant to the sensory degradation effects of optical blur and retinal eccentricity. Only the orientation task requires a reasonable level of visual acuity (better than 6/18). The perceptual learning effect is minimal, therefore little practice is required prior to clinical application of the test. The sensory and motor effects of age are rendered negligible through the development of a measure of perceptual search ability. The test therefore remains clinically robust. In relation to glaucomatous neuropathy, the test yields consistently high sensitivity and specificity for each task and thus appears to provide a suitable means of glaucoma detection. Conclusions: All investigations thus far indicate that, at the very least, the test provides a simple, rapid and accurate means of screening for the effects of glaucomatous optic neuropathy. Its capacity to differentiate glaucoma from suspects suggests its diagnostic ability extends beyond that achieved by conventional perimetry. Longitudinal analysis should confirm whether this is true

Preattentive Visual Search (PAVS): A Clinical Tool for Glaucoma

Glaucoma is known to cause peripheral field loss but its impact is often underestimated. The inability to detect a target in an isolated area of the visual field may not be perceived as a significant disability. The determination here however that glaucoma adversely affects an individual’s capacity to deploy attention is an important one. This can be applied to infer the potential impact of the condition on lifestyle, even in the absence of diffuse perimetric field loss. Everyday tasks such as searching for car keys may prove more tedious and require more serial inspection. The ability to guide attention is a fundamental capacity of the human system and when compromised through visual dysfunction has the potential for devastating consequences

Application of big-data for epidemiological studies of refractive error

To examine whether data sourced from electronic medical records (EMR) and a large industrial spectacle lens manufacturing database can estimate refractive error distribution within large populations as an alternative to typical population surveys of refractive error

Meso-Zeaxanthin Ocular Supplementation Trial in Normals (MOST-N)

Purpose: At the macula, the carotenoids meso-zeaxanthin (MZ), lutein (L) and zeaxanthin (Z) are collectively referred to as macular pigment (MP). To date only one study has reported on MP augmentation following supplementation with MZ, L and Z. However, that study measured only one retinal location (0.75°) and may not have been able to detect changes, if any, at other degrees of retinal eccentricity. Our study was designed to investigate (in a double-blind, randomized placebo controlled fashion) changes in MP optical density (MPOD, including its entire spatial profile), and serum concentrations of the macular carotenoids in response to supplemental MZ, L and Z in healthy subjects. Methods: We recruited 44 healthy subjects for this study. 22 subjects were randomized to consume a formulation containing 10.6 mg of MZ, 5.9 mg of L and 1.2 mg of Z (Intervention [I] group), and 22 subjects consumed a placebo everyday over a six month period (Pleacebo [P]) group). At each study visit (Baseline [V1], 3 months [V2], and 6 months [V3]) the spatial profile of MPOD (i.e. at 0.25°, 0.5°, 1° and 1.75°) was measured using customised heterochromatic flicker photometry and a blood sample was collected to analyse serum concentrations of L and Z using high performance liquid chromatography. Results: The mean ± SD age of our subjects was 43.54 ± 12.2. There was a statistically significant increase in serum concentrations of L and Z (μmol/L) and MPOD at 0.25° and 0.5° retinal eccentricity at V2 and V3 in the I group (p 0.05, for all). Conclusions: Our findings are consistent with previous supplementation studies that have shown increases in serum concentrations of L and Z and MPOD following supplementation with the macular carotenoids. Interestingly, the greatest increase seen in this study was at the centre (0.25°) following supplementation with an MZ dominant formulation

Natural History and Conservation Biology of a Southern West Virginia Contour Surface Mine Reptile and Amphibian Community

During the 2004-2005 field seasons, natural history of a herpetofaunal community was studied on an abandoned contour surface mine in Eccles, Raleigh County, West Virginia. This study is the first natural history investigation of amphibian and reptile populations present on an abandoned mine site. Specific natural history parameters for each order on the mine were investigated to determine what effect the post mining landscape had on herpetofaunal communities. Pond breeding caudates population success was dependent on life history parameters. Anurans were efficient at re-colonization, with 12 of a possible 14 species collected on the mine site. Anuran diversity was linked to niche partioning. Testudine populations were limited by the mine’s landscape, and were not successful at colonizing the mine. Ophidians utilized the mine seasonally when mine thermal regimes did not lead to physiological stress. Overall, the mine favored reptiles and amphibians that displayed generalist species characteristics and favored R selection

The Acceptability and Visual Impact of 0.01% Atropine in a Caucasian Population

Myopia is a condition of enormous public health concern, affecting up to 2.5 billion people worldwide. The most effective treatment to prevent myopia progression is atropine but at the cost of accommodative paresis and mydriasis, necessitating the use of bifocal glasses. Low-dose atropine (0.01%) has been found to be almost as effective with significantly reduced side effects. Since there are well-recognised differences in the effect of atropine between heavily pigmented Asian eyes and Caucasian eyes, this study aimed to determine the acceptability and tolerability of 0.01% atropine (by measuring visual performance and quality of life) as a treatment for myopia control in a Caucasian population exhibiting light irides. Methods 14 university students aged 18–27 were recruited to the study. Participants received one drop of 0.01% atropine daily into each eye over 5 days. A range of physiological, functional and quality of life measures were assessed at baseline, day 3 and day 5. Results The effect of atropine was statistically significant for pupil size (p=0.04) and responsiveness (p\u3c0.01). While amplitude of accommodation reduced, the change was not statistically significant. Visual acuity (distance and near) and reading speed were not adversely affected. While there was a slight increase in symptoms such as glare, overall there was no quality of life impact associated with the use of low-dose atropine

Expanding the Traditional Role of Optometry: Current Practice Patterns and Attitudes to Enhanced Glaucoma Services in Ireland

Purpose: To investigate current diagnostic equipment availability and usage for glaucoma casefinding within community optometric practice, and to explore optometrists’ attitudes towards an enhanced scope of clinical practice. Methods: An anonymous survey was developed, validated, and distributed to all optometrists in Ireland. Results: 199 optometrists (27% of registrants) responded to the survey. 87% had access to the traditional triad of tests necessary to conduct adequate glaucoma case finding. Standard automated perimetry was the most commonly absent (13%) of the three essential screening tests. 64% of respondents indicated that monocular direct ophthalmoscopy was their first choice technique for fundus examination. 47% of respondents had access to contact applanation tonometry, though just 14% used it as first choice during routine eye examinations. Among the 73 participants with access to both contact and non-contact tonometry (NCT), 80.8%, used NCT preferentially. The significant majority (98%) indicated an interest in enhanced glaucoma services with 57% agreeing that postgraduate training was an essential prerequisite to any increase in scope of practice. Conclusion: Irish optometrists are well equipped with the traditional tests used in glaucoma detection. However, implementation of enhanced referral schemes or glaucoma monitoring or management services would require equipment upgrades and associated training in at least half of the surveyed practices. There is strong interest in furthering optometric professional development and expanding the traditional role boundaries of optometrists, incorporating further education as an essential prerequisite to an enhanced scope of practice