Improved visualisation of choroidal neovascularisation by scanning laser ophthalmoscope using image averaging

Abstract

Aims: To improve visualisation of angiographic features in patients with age related macular degeneration associated with choroidal neovascularisation (CNV) and related complications. To evaluate if image averaging can achieve this goal. Methods: 27 eyes of 20 sequential patients with age related macular degeneration over a 3 month period were studied. Indocyanine green angiograms (ICGA), fluorescein angiograms (FA), and oral fluorescein angiograms were recorded with a confocal scanning laser ophthalmoscope. Software was used to average multiple images from a 10-20 image series (over 0.5-1.0 seconds). Image quality was assessed by two masked observers and graded on a scale of 0-3. A more quantifiable grading method was devised by adding a variable amount of Gaussian noise to the improved image until the original and image averaged image appeared equal. Results: Masked review showed mild to strong improvement of visualisation of structures including borders of CNV. Improvement varied depending on the type and phase of the angiogram. Improvement was highest in late phase FA, mid and late phase ICGA, and all phases of oral FA. Conclusion: Image averaging using software based algorithms improves the quality of angiographic images, particularly late ICGA images and oral FAs. This method may assist in the visualisation of choroidal neovascularisation in age related macular degeneration.

Correlation between Spectral-Domain Optical Coherence Tomography and Fundus Autofluorescence at the Margins of Geographic Atrophy

“…The fundus images are obtained with a confocal scanning laser ophthalmoscope combined with the OCT system. Fundus autofluorescence images were recorded using Spectralis or a confocal Scanning Laser Ophthalmoscope (HRA2, Germany), the optical and technical principles of which have been described previously 15 16 17. The field size was selected as 30° × 30° at 1,536 × 1,536 pixels.…”

Tear film evaluation by scanning laser ophthalmoscopy during retinal imaging

“…9,10 Scanning laser ophthalmoscopy (SLO) is a confocal scanning laser microscopy for retinal or corneal imaging of the human eye. 11,12 The most recent introduced version of Spectralis (Heidelberg Engineering, Inc., Franklin, MA), a commercially available SLO system, has the ability to acquire both spectral domain-optical coherence tomography (SD-OCT), fluorescein angiography (FA), and the multicolor images of the retina by using three different wavelengths (infrared, green, and blue). This device offers a combination-pseudocolor-image by combining three wavelength images into a single image.…”

Depth-resolved wavefront aberrations using a coherence-gated Shack-Hartmann wavefront sensor

“…In order to reduce the effect of the cornea reflections, different methods have been suggested, such as: (i) moving the lenses and mirrors in the interface optics off axis [13]; (ii) using a polarization beam splitter to eliminate specular reflections [14] and (iii) off-axis illumination of the retina so that the light coming back from the retina is along a different path than that followed by the back reflections [15]. However, all these methods present disadvantages, (i) leads to further aberrations, (ii) produces signal loss and dependence on the polarization of the sample whereas (iii) requires separation of imaging and WFS paths and two optical sources.…”