The thesis investigated progression of the central 10° visual field with structural
changes at the macula in a cross-section of patients with varying degrees of agerelated
macular degeneration (AMD). The relationships between structure and function
were investigated for both standard and short-wavelength automated perimetry
Factors known to influence the measure of visual field progression were considered,
including the accuracy of the refractive correction on SWAP thresholds and the
learning effect. Techniques of assessing the structure to function relationships
between fundus images and the visual field were developed with computer
programming and evaluated for repeatability. Drusen quantification of fundus
photographs and retro-mode scanning laser ophthalmoscopic images was performed.
Visual field progression was related to structural changes derived from both manual
and automated methods.
• Visual field sensitivity declined with advancing stage of AMD. SWAP showed
greater sensitivity to progressive changes than standard perimetry.
• Defects were confined to the central 5°. SWAP defects occurred at similar
locations but were deeper and wider than corresponding standard perimetry
• The central field became less uniform as severity of AMD increased. SWAP
visual field indices of focal loss were of more importance when detecting early
change in AMD, than indices of diffuse loss.
• The decline in visual field sensitivity over stage of severity of AMD was not
uniform, whereas a linear relationship was found between the automated
measure of drusen area and visual field parameters.
• Perimetry exhibited a stronger relationship with drusen area than other measures
of visual function.
• Overcorrection of the refraction for the working distance in SWAP should be
avoided in subjects with insufficient accommodative facility.
• The perimetric learning effect in the 10° field did not differ significantly between
normal subjects and AMD patients.
• Subretinal deposits appeared more numerous in retro-mode imaging than in
|Date of Award||Feb 2010|
|Supervisor||Robert P Cubbidge (Supervisor)|
- short-wavelength automated perimetry
- scanning laser ophthalmoscope
Visual field and structural alterations in age-related macular degeneration
Acton, J. H. (Author). Feb 2010
Student thesis: Doctoral Thesis › Doctor of Philosophy