Optometry Commons^™

Soft Contact Lens-Induced Corneal Warpage, Aoife Lloyd Mckernan, Luisa Simo Mannion, Linda Moore

Articles

No abstract provided.

The Impact Of Macular Pigment Augmentation On Visual Performance In Normal Subjects: Compass, John Nolan, James Loughman, Akkali Makunda, Jim Stack, Grainne Scanlon, Peter Davison, Stephen Beatty

Articles

This study was conducted to investigate whether augmentation of macular pigment (MP) enhances visual performance (VP). 121 normal subjects were recruited. The active (A) group consumed 12 mg of lutein (L) and 1 mg of zeaxanthin (Z) daily. MP optical density (MPOD) was assessed by customized heterochromatic flicker photometry. VP was assessed as best corrected visual acuity (BCVA), mesopic and photopic contrast sensitivity (CS), glare disability, photostress, and subjective visual function. Subjects were assessed at baseline; 3; 6; 12 months (V1, V2, V3 and V4, respectively). Central MPOD increased significantly in the A group (p < 0.05) but not in the placebo group (p > 0.05). This statistically …

Online Amd Research Study For Optometrists: Current Practice In The Republic Of Ireland And Uk, James Loughman, John Nolan, James Stack, Stephen Beatty

Articles

No abstract provided.

Psychophysical Impact And Optical And Morphological Characteristics Of Symptomatic Non-Advanced Cataract., S. Charalampidou, J. Nolan, James Loughman, J. Stack, Lorraine Cassidy, S. Beatty

Articles

Purpose To investigate whether
/="/">psychophysical, morphological, and/or optical
/="/">characteristics of symptomatic non-advanced
/="/">cataract are complementary to, or more
/="/">appropriate than, visual acuity (VA) for the
/="/">purposes of recording visual data that reflect
/="/">subjective visual difficulty in patients with
/="/">cataract that exhibit relative sparing of high
/="/">contrast acuity (0.4 logarithm of minimal angle
/="/">of resolution (logMAR) scale or better).

Effect On Refractive Outcomes After Cataract Surgery Of Intraocular Lens Constant Personalization Using The Haigis Formula, Sofia Charalampidou, Lorraine Cassidy, Eugene Ng, James Loughman, John Nolan, Jim Stack, Stephen Beatty

Articles

Methods Personalization of Haigis IOL constants was performed using a series of 248 suitable eyes after biometry by partial coherence interferometry (IOLMaster) and IOL prediction based on optimized IOL constants derived from pooled data from the User Group for Laser Interference Biometry web site. A mean error of prediction and a mean absolute error were then calculated using the personalized IOL constants and compared with those derived using optimized IOL constants, allowing evaluation and quantification of the maximum realizable refractive benefits (if any) of personalization. Results There was no statistically significant difference between personalized and optimized Haigis IOL constants in …

Augmentation Of Macular Pigment Following Supplementation With All Three Macular Carotenoids: An Exploratory Study, Eithne Connolly, Stephen Beatty, David Thurnham, James Loughman, Alan Howard, Jim Stack, John Nolan

Articles

Purpose:At the macula, the carotenoids meso-zeaxanthin (MZ), lutein (L), and zeaxanthin (Z) are collectively referred to as macular pigment (MP). This study was designed to measure serum and macular responses to a macular carotenoid formulation. Materials and Methods:Ten subjects were recruited into this study (five normal and five with early age-related macular degeneration [AMD]). Subjects were instructed to consume a formulation containing 7.3mg of MZ, 3.7mg of L, and 0.8mg of Z everyday over an eight-week period. The spatial profile of MP optical density (i.e., MPOD at 0.25°, 0.5°, 1°, and 1.75°) was measured using customized heterochromatic flicker photometry, and …

The Relationship Between Macular Pigment And Visual Performance, James Loughman, Mukunda Akkali, Stephen Beatty, Grainne Scanlon, Peter Davison, Veronica O'Dwyer, Thomas Cantwell, Philip Major, Jim Stack, John Nolan

Articles

This study was designed to assess whether macular pigment optical density (MPOD) is associated with visual performance. One hundred and forty-two young healthy subjects were recruited. Macular pigment optical density and visual performance were assessed by psychophysical tests including best corrected visual acuity (BCVA), mesopic and photopic contrast sensitivity, glare sensitivity, photostress recovery time (PRT). Measures of central visual function, including BCVA and contrast sensitivity, were positively associated with MPOD (p < 0.05, for all). Photostress recovery and glare sensitivity were unrelated to MPOD (p > 0.05). A longitudinal, placebo-controlled and randomized supplementation trial will be required to ascertain whether augmentation of MPOD can influence visual performance.

Surgically Induced Astigmatism After Phacoemulsification With And Without Correction For Posture-Related Ocular Cyclotorsion, I. Dooley, S. Charalampidou, A. Malik, G. Ormonde, James Loughman, Laura Molloy, Stephen Beatty

Articles

Purpose To report the impact of posture-related ocular cyclotorsion on one surgeon's surgically induced astigmatism (SIA) results and the variance in SIA. Setting Institute of Eye Surgery, Whitfield Clinic, Waterford, Ireland. Methods This prospective randomized controlled study included eyes that had phacoemulsification with intraocular lens implantation. Eyes were randomly assigned to have (intervention group) or not have (control group) correction for posture-related ocular cyclotorsion. In the intervention group, the clear corneal incision was placed precisely at the 120-degree meridian with instruments designed to correct posture-related ocular cyclotorsion. In the control group, the surgeon endeavored to place the incision at the …

Macular Pigment And Its Contribution To Visual Performance And Experience, James Loughman, Peter Davison, John Nolan, Mukunda Akkali, Stephen Beatty

Articles

There is now a consensus, based on histological, biochemical and spectral absorption data, that the yellow colour observed at the macula lutea is a consequence of the selective accumulation of dietary xanthophylls in the central retina of the living eye. Scientifi c research continues to explore the function(s) of MP in the human retina, with two main hypotheses premised on its putative capacity to (1) protect the retina from (photo)-oxidative damage by means of its optical fi ltration and/or antioxidant properties, the so-called protective hypothesis and (2) infl uence the quality of visual performance by means of selective short wavelength …

Macular Pigment Optical Density In An Aging Irish Population: The Irish Longitudinal Study On Ageing, John Nolan, Roseanne Kenny, Claire O'Regan, Hilary Cronin, James Loughman, Eithne Connolly, Patricia Kearney, Stephen Beatty

Articles

Purpose: The 3 carotenoids lutein, zeaxanthin, and meso-zeaxanthin, which account for the ‘yellow spot’ at the macula and which are referred to as macular pigment (MP), are believed to play a role in visual function and protect against age-related macular degeneration (AMD) via their optical and antioxidant properties. This study was undertaken to compare MP optical density (MPOD) in a population aged ≧50 years with MPOD values from a normative database of subjects aged 18–60 years. Methods: Seventy-nine subjects were recruited into this pilot study (The Irish Longitudinal Study on Ageing-TILDA). MPOD was measured using heterochromatic flicker photometry. Retinal fundus …

Changes In Intraocular Pressure And Anterior Segment Morphometry After Uneventful Phacoemulsification Cataract Surgery, J. Dooley, S. Charalampidou, A. Malik, James Loughman, L. Molloy, S. Beatty

Articles

Purpose To study changes in anterior segment morphometry after uneventful phacoemulsification cataract surgery, and to investigate whether there is a relationship between any observed changes and intraocular pressure (IOP) reduction after the procedure. Methods The anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), central corneal thickness (CCT), and IOP were measured in 101 non-glaucomatous eyes before and after uneventful phacoemulsification cataract surgery. Results After cataract surgery, the mean ACD, ACV, and ACA values increased by 1.08mm, 54.4mm3, and 13.11, respectively, and the mean IOP (corrected for CCT) decreased by 3.2mmHg. The predictive value of a previously …

Macular Pigment And Its Contribution To Visual Performance And Experience [El Pigmento Macular Y Su Contribución Al Rendimiento Y Experiencia Visuals], James Loughman, Peter Davison, John M. Nolan, Mukunda C. Akkali, Stephen Beatty

Articles

There is now a consensus, based on histological, biochemical and spectral absorption data, that the yellow colour observed at the macula lutea is a consequence of the selective accumulation of dietary xanthophylls in the central retina of the living eye. Scientific research continues to explore the function(s) of MP in the human retina, with two main hypotheses premised on its putative capacity to (1) protect the retina from (photo)-oxidative damage by means of its optical filtration and/or antioxidant properties, the so-called protective hypothesis and (2) influence the quality of visual performance by means of selective short wavelength light absorption prior …

Diagnostic Sensitivity/Specificity Of Preattentive Vision Tests In Glaucoma, James Loughman, Peter Davison, Daniel Ian Flitcroft

Articles

Purpose. Damage to the nerve fiber layer or visual pathway might be expected to reduce the efficiency with which the visual system performs analysis of the ever-changing field of vision. The purpose of this article is to provide a further analysis of previously reported data (Loughman J, Davison P, Flitcroft I, Br J Ophthalmol 2007;91:1493-98.) to: (i) determine the sensitivity and specificity of a test of preattentive vision for glaucoma detection and (ii) provide a cutoff performance level that would serve to distinguish glaucoma in early cases. Methods. Three groups of observers (glaucoma, suspects, and normals) were examined, using computer-generated …

Diagnostic Sensitivity/Specificity Of Preattentive Vision Tests In Glaucoma, James Loughman, Peter Davison, Daniel Ian Flitcroft

Articles

Purpose. Damage to the nerve fiber layer or visual pathway might be expected to reduce the efficiency with which the visual system performs analysis of the ever-changing field of vision. The purpose of this article is to provide a further analysis of previously reported data (Loughman J, Davison P, Flitcroft I, Br J Ophthalmol 2007;91:1493–98.) to: (i) determine the sensitivity and specificity of a test of preattentive vision for glaucoma detection and (ii) provide a cutoff performance level that would serve to distinguish glaucoma in early cases. Methods. Three groups of observers (glaucoma, suspects, and normals) were examined, using computer-generated …

Open Angle Glaucoma Effects On Preattentive Visual Search (Pavs) Efficiency For Flicker, Motion Displacement And Orientation Pop-Out Tasks, James Loughman, Peter Davison, Daniel Ian Flitcroft

Articles

Background/aim: Preattentive visual search (PAVS) describes rapid and efficient retinal and neural processing capable of immediate target detection in the visual field. Damage to the nerve fibre layer or visual pathway might reduce the efficiency with which the visual system performs such analysis. The purpose of this study was to test the hypothesis that patients with glaucoma are impaired on parallel search tasks, and that this would serve to distinguish glaucoma in early cases. Methods: Three groups of observers (glaucoma patients, suspect and normal individuals) were examined, using computer-generated flicker, orientation, and vertical motion displacement targets to assess PAVS efficiency. …

Open Angle Glaucoma Effects On Preattentive Visual Search (Pavs) Efficiency For Flicker, Motion Displacement And Orientation Pop-Out Tasks, James Loughman, Peter Davison, Ian Flitchcroft

Articles

Background/aim: Preattentive visual search (PAVS) describes rapid and efficient retinal and neural processing capable of immediate target detection in the visual field. Damage to the nerve fibre layer or visual pathway might reduce the efficiency with which the visual system performs such analysis. The purpose of this study was to test the hypothesis that patients with glaucoma are impaired on parallel search tasks, and that this would serve to distinguish glaucoma in early cases. Methods: Three groups of observers (glaucoma patients, suspect and normal individuals) were examined, using computer-generated flicker, orientation, and vertical motion displacement targets to assess PAVS efficiency. …

Population Study Of The Variation In Monochromatic Aberrations Of The Normal Human Eye Over The Central Visual Field, Matthew Sheehan, Alexander Goncharov, Veronica O'Dwyer, Vincent Toal, Christopher Dainty

Articles

Abstract

We present data analysis for ocular aberrations of 60 normal eyes measured with a Hartmann-Shack (HS) wavefront sensor (WFS). Aberration measurements were made on-axis and at 5 degree field angles in the nasal, inferior, temporal and superior semi-meridians. Particular attention is given to aberration distributions and possible strategies for aberration correction are discussed. A versatile HS WFS was designed and constructed with features of simultaneous pupil centre determination, off-axis capability, real-time data displays, and efficient lenslet sampling orientation. The subject alignment is achieved by the use of a parallel channel that is recombined with the sensing channel to simultaneously …

Effects Of Retinal Image Degradation On Pre-Attentive Visual Search (Pavs) Efficiency For Flicker, Movement And Orientation Stimuli, Peter Davison, James Loughman

Articles

Background: Previous research has shown that several clinical conditions cause increased preattentive visual search (PAVS) times, implying reduced parallel search capabilities in glaucoma and DLB dementia. The purpose of the research reported here was to examine for the first time the resistance of PAVS to dioptric blur using targets differing from the background in terms of flicker, vertical displacement, and orientation. Resistance would enhance the applicability of PAVS as a screening method for glaucoma and other clinical conditions affecting performance of a substantial area of the retina. Method: Computer generated flicker, orientation and vertical displacement targets were used to assess …

Effects Of Retinal Image Degradation On Pre-Attentive Visual Search (Pavs) Efficiency For Flicker, Movment And Orientation Stimuli, Peter Davison, James Loughman

Articles

Background: Previous research has shown that several clinical conditions cause increased pre-attentive visual search (PAVS) times, implying reduced parallel search capabilities in glaucoma and DLB dementia. The purpose of the research reported here was to examine for the first time the resistance of PAVS to dioptric blur using targets differing from the background in terms of flicker, vertical displacement, and orientation. Resistance would enhance the applicability of PAVS as a screening method for glaucoma and other clinical conditions affecting performance of a substantial area of the retina. Method: Computer generated flicker, orientation and vertical displacement targets were used to assess …