Ординатура / Офтальмология / Английские материалы / Scanning Laser Imaging of the Retina Basic Concepts and Clinical Applications_Theelen_2011

Dankwoord 231

232 Dankwoord

Color images 233

COLOR IMAGES

234 Color images

236 Color images

Fig. 3.3 ◙

24-bit color image of a patient with cone-rod dystrophy (A). The image consists of the blue (B), green (C) and red (D) channel. Note that the optic nerve head is best visualized in blue, macular pathology is best visible in green and the red channel gives an impression of melanin distribution.

Fig. 3.9 ◙

Results of image overlay with and without registration of source and target image. Note the ghost vessels as a result of bad pixel correspondence in the upper row. In the color image, yellow and black pixels represent good correlation while red and green ones stand for bad correspondence.

Color images 237

Fig 4.2 ◙

Reflecting retinal layers in the near-infrared. The illuminating beam (red arrows) is reflected by diverse intraand subretinal layers for diverse extents. Strongest reflection is provided by the sclera (SCL), a smaller amount by the retinal photoreceptor layer (PRL) and the retinal pigment epithelium (RPE). Small amounts of reflections originate from the inner limiting membrane (ILM) while the retinal nerve fiber layer (RFNL) only gives important reflections in the near vicinity of the optic nerve. The number and length of the blue arrows indicate the degree of near infrared reflectance.

Fig. 4.4 ◙

Near­infrared reflectors and absorbers in choroidal neovascularization. A multitude of reflecting (arrows point up) and absorbing (arrows point down) elements add to the near­infrared reflectance image of a choroidal neaovascularization (CNV). The length of the arrows indicated the strength of the optical effects. Unmasked fibrin (yellow dots) is a strong reflector while fluid appears main the absorber. CL=CNV; CH=choroidea; OC=occult CNV; RE= retina

238 Color images

Fig. 4.16 ◙

Follow-up during intravitreal anti-VEGF therapy of a RAP lesion. The left image faction shows early (left column) and late phase FFA (middle column) as well as NIR (right column) before (A-C) and after three (D-F) and six (G-I) intravitreal applications of bevacizumab. Late leakage on FFA becomes markedly reduced (B,E,H) whilst the initial dark halo on NIR disappears (C,F,I) during treatment. Digital subtraction analysis of the standardized NIR images illustrates the increase of NIR around the RAP lesion after the first treatment series (J, yellow-red spots). Some foci of extreme NIR elevation, which appear as lipid exudates on funduscopy (L-M), disappear in the due course (K, blue spots). Images were contrast enhanced for improved visualization.

Fig. 4.17 ◙

Illustrated co-localization analysis of melanin and increased NIR in CNV. In a classic CNV case, regions with increased pigmentation on color fundus photograph (A) and areas of increased NIR (C) were segmented by thresholding and superimposed after image alignment (B). Total areas summed up to 0.44 mm², where 0.32 mm² accounted to melanin and 0.25 mm² to NIR increase. Both areas shared 0.14 mm², which resulted in a colocalization of 32%. Images were contrast enhanced for better performance. Segmented layers (B): green = melanin, red = NIR increase, yellow = shared pixels of melanin and NIR increase

Color images 239

Fig. 5.7 ◙

Image series from a video mode SW-AF measurement (panel A, 5 frames per second, plotted left to right and top to bottom) and the mean gray values of the images (panel B), demonstrating bleaching kinetics. During SW light illumination, AF increase (panel A; false colors specify AF intensity) occurred largely within a circular area of 11° eccentricity centered to the fovea. The total increase of SW-AF during photopigment bleaching, which is 20.6 per cent of baseline, fits asymptotic kinetics (panel B; black curve). The resulting change of photopigment density during this measurement is 0.08.

Fig. 5.9 ◙

Topographic analysis of visual pigment density difference map by SW-AF in a healthy subject. The red graph (panel A) depicts the multiple peak Gaussian fit of the plotted gray values within 360 pixels radius around the fovea (panel B; red circle). While the density difference between dark adapted and bleached state peaked temporally and nasally it declined superiorly and inferiorly. Two-dimensional distribution of differences in optical density are better noticeable in the false color coded density map (panel C); according to the color level definition in panel A, warmer colors indicate increased optical density. S=superior, T=temporal, I=inferior, N=nasal

240 Color images

Fig. 5.12 ◙

Fundus appearance of the macula in Sjögren-Larsson syndrome. Color fundus photographs of a patient with Sjögren-Larsson syndrome (A) and a normal control (B). The brightness of macular background is relatively homogenous in the patient, while a considerable central darkening due to macular pigment is present in the healthy control. Note the huge amount of intraretinal crystals in the Sjögren-Larsson patient.

Fig. 5.20 ◙

Morbus Stargardt. (a) Color fundus photography shows typical yellow-white, pisciform flecks. In addition, irregularities of the retinal pigment epithelium may be observed at the macula. (b) FAF488 reveals focally increased signals at the flecks, but also at some clinically unremarkable areas. At the macula, FAF488 appears to be irregularly distributed and shows focally reduced intensity. (c) Near-infrared reflectance is increased at flecks and atrophic areas. (d) Using FAF787 more and larger lesions than in FAF488 appear with a predominantly low autofluorescence signal.