How to Acquire thePerfect Image


The Technology of FusionHeidelberg Engineering has spent many years working closely with the world’sleading doctors and imaging specialists developing new technologies to preventsight loss. Most major research centers and teaching hospitals use our products, as well as a large number of general clinics and private practices.The Heidelberg SPECTRALIS HRA OCT provides a unique combination of retinal angiography and optical coherence tomography.The ability of the SPECTRALIS HRA OCT to automaticallymaintain the OCT scan at the selected location guarantees the correct alignmentbetween OCT scan and its position on the fundus. The built in real time eye-tracking system minimizes the influence of eye-movement artifacts and allows highly reproducible follow up examinations. Becauseof TruTrack alignment technology, the instrument has a high degree of reproducibility, as low as 1 micron1.Simultaneous digital Fluorescein angiography (FA) and Indocyanine green angiography (ICGA) images improve the diagnosis of retinal and choroidal pathologies such as diabetic retinopathy and AMD. High Speed ICG imaging can identifyfeeder vessels and retinal choroidal anastomoses for more effective treatment of CNV.BluePeak blue laser autofluorescence imaging and fundus reflectance imaging with infrared and blue reflectance lightcontain additional information for identifying various manifestations of retinal disease. SPECTRALIS HRA OCT enablesaccurate diagnosis and monitoring of patients. The low light levels used in the SPECTRALIS scanning laser and OCTtechnology result in examinations which are comfortable and safe for patients.By offering you this guide on “How to acquire the perfect image“, we hope to give you an easy start with the SPECTRALISHRA OCT.1Wolf-Schnurrbusch UE et al. Macular Thickness Measurements in Healthy Eyes Using Six Different Optical Coherence TomographyInstruments. Invest Ophthalmol Vis Sci. 2009;50:3432-3437.Table of ContentsSPECTRALIS Acquisition Modes . 3Acquisition Protocol SPECTRALIS HRA OCT . 5Specific Acquisition Modes . 61. Infrared reflectance (IR) .62. Blue reflectance (BR) .63. BluePeak blue laser autofluorescence (BAF) .74. MultiColor .85. Fluorescein angiography (FA) .96. Indocyanine green angiography (ICGA) .107. Optical Coherence Tomography (OCT) . 118 High Magnification .169. Wide Field Images (Composite, Wide Field Lens, Ultra-Wide Field Lens) .1610. Mean Images .1911. Stereo Images . 2012. Simultaneous Images .2113. Tomography Scans . 2214. Anterior Segment Images. 2315. Acquisition Default Settings . 2316. Resolution Modes / Image Brightness / High Myopia Compensation. 2417. Lens Cleaning . 2418. Touch Panel . 2519. Application Matrix . 274

Acquisition ProtocolSPECTRALIS HRA OCTGeneral Workflow Create „New Patient“ database entry or choose existing patient for re-examination. Move the camera to the farthest back position. Clean camera chinrest and forehead rest - preferably when patient can see you doing so. Check that lens is clean Adjust table height and chinrest for the patient. Turn camera on. Select acqusition mode using the filter wheel (R Reflectance modes, A Angiography modes,P Polarization mode) on the touch panel. Ask patient to place the chin on the chinrest and to lean the forehead against the forehead rest. Make sure red line on chinrest pole is at canthus level. Align camera with pupil and move camera forward. Acquire images. Move camera backwards and then over to the fellow eye. Acquire images of the fellow eye. Exit acquisition window. Images are automatically saved. Select and delete any low quality or duplicate images.5

Specific Acquisition Modes1. Infrared reflectance (IR)The first acquisition is usually done in IR mode. These images are taken before ICGA or FA image capture. As with all images,aim for even illumination, minimal artifacts and centering of the macula, unless otherwise indicated. In the case of IR, it ispossible to have too much illumination. Overexposed images are a sign of excessive light. In this case reduce the IR laserintensity on the touch panel as needed. Slight overexposure can be reduced by turning the ART / Sensitivity knob (Fig. 4).IRIRFig.1: Overexposed imageFig. 2: Improved image qualityNote: In case of overexposure first reduce the laser intensitiy, then reduce the sensitivity!Fig. 3: IR intensity at 25 % at touch panelFig. 4: ART / Sensitivity-knob2. Blue reflectance (BR)Blue reflectance images are taken as a control image set before FA and ICGA. BR acquisition mode is activated by movingthe filter wheel from position „A“ to position „R“. In order to minimize the amount of visible light exposure to the patient’seye, set the image in IR mode and then switch to BR for acquisition. For a high quality Blue reflectance image, the sensitivity should be subsequently increased and the focus adjusted, so that the focus of the IR image varies by approx. -0.5 D.BR6Fig. 5Fig. 6

3. BluePeak blue laser autofluorescence (BAF)The high quality of SPECTRALIS HRA OCT BluePeak blue laser autofluorescence imaging offers information beyond conventional fundus images orFluorescein angiography. BAF is used for a variety of purposes, from outliningoptic nerve head drusen (previously the standard use of BAF in fundus cameras), to studying various manifestations of the age-related macular diseases andhereditary retinal disorders without the injection of fluorescein dye.Align the camera as outlined above, using the IR acquisition mode. Once you seea sharp, well-focused image, change to the BAF illumination. Adjust the focusas recommended for BR-imaging. The image will now be considerably darker,however, increasing sensitivity will outline the retinal blood vessels (Fig. 7, 8).Fig. 7Quick Tips: BAF Increase sensitivity until retinal vessels areseen. Activate the ART Mean function and acquire the image. Dilating the pupils can increase imagequality. Images must be aquired before starting FA.Fig. 8BAFTo receive a BAF image with good quality, at least 6-24 single scans must be acquired and averaged. The following methodsare available:1. Recommended method: By pressing the ART / Sensitivity knob on the Touch Panel you can activate the ART(Automatic Real Time) Mean function to generate a live Mean BluePeak blue laser autofluorescence image onlineand view it as it is created.2. Multiple single images3. Short movieFollowing the acquisition, methods 2 and 3 only, use the „Compute Mean“ functionin the HEYEX (Fig. 9). Compute mean images for all the BAF images you have taken(Fig. 10, 11), before proceeding with the FA.AFBAF (Mean)Fig. 10Fig. 11Fig. 9: „Compute Mean“ functionNote: After the injection of fluorescein dye, it will be impossible to perform BAF imaging.When using method 2 or 3, evaluate the resultant mean images, and if necessary, repeat. Small eye movements, which werepotentially invisible during acquisitionmay lead to unclean image calculation.When eye movements result in poormean images, it is possible to either usethe „Compute Composite“ mode (Fig. 13),to delete the images from within the meanseries showing eye movement then recalBAFBAFculate the mean. You may also re-acquire(Mean)(Composite)the series.Fig. 12Fig. 137

4. MultiColorThe MultiColor acquisition consists of three simultaneously acquired, colorselective laser images. The individual laser colors highlight the structural detailsof various retinal layers (Fig. 14-17).MultiColor images deliver sharp and detailed fundus images even under difficult circumstances, such as patient’s suffering from cataract and nystagmus.Quick Tips: MultiColor Position filter wheel to „R“. Adjust the focus in BR mode until smallretinal blood vessels are clearly visible. Activate the ART Mean function and acquire image. Dilation may improve image quality.MCFig. 14: MultiColor imageFig. 15: Blue reflectance Fig. 16: Green reflectance Fig. 17: Infrared-reflectanceCheckbox for perfect MultiColor Images To prepare MultiColor acquisition, turn SPECTRALIS HRA OCT filter wheel to position „R“.To avoid disturbing the patient’s eyes, illuminate and focus the fundus in IR mode correctly.To acquire an image of the macular area, optimize the focus by looking at small blood vessels while in BR mode.Select the function „More“ on the touch panel. To start MultiColor acquisition mode, select „MColor“ (Fig.18).Always activate the ART Mean function during MultiColor acquisition.Fig. 18: Activation of the MultiColor acquisition modeNote:Varying the image focus changes the depth scanning information in the MultiColor image.Focus in BR-mode: image is focused on inner retinal layer, retinal nerve fibre layer, internal limiting membrane,retinal blood vessels.Focus in IR-mode: image is focused on outer retinal layer, retinal pigment epithelium, choroid.8

Avoiding image artifacts The most common cause of image artifacts is a weak or an unevenly illuminated image during acquisition (Fig. 19). An incorrectly focused MultiColor image also leads to appearance reflection at artifacts in image acquisition (Fig. 20).Do not perform any examinations that disturb the tear film before MultiColor acquisition; use artificial tears inpatients with dry eyes (Fig. 21).Fig. 19: Artifact due to poor image Fig. 20: Artifact due to poor focus Fig. 21: Artifact due to dry eyesilluminationNote:- MultiColor images are not fundus photos and can vary from clinical view.- MultiColor images can only be acquired in High Speed mode (HS).- Stereo images cannot be acquired in MultiColor acquisition mode.5. Fluorescein angiography (FA)FA images are taken after the fluorescein dye has been injected. The location ofthe vein (arm / hand) usually has bearing on the time it takes the dye to reachthe eye. While taking images of the early stages it is important to adjust thebrightness of the images as necessary by turning the ART / Sensitivity knob(Fig. 22-24).FA18 seconds20 seconds25 secondsFig. 22Fig. 23Fig. 24Quick Tips: FA During the early stage pay special attention to the brightness adjustment. Acquire movies of early stages, then deleteif not needed. Use ART Mean function for late / darkimages.Taking FA photos is essentially not much different from recording non-angiography images. Knowledge and understanding of the pathology to be documented are essential for the area to be documented and the correct level of illuminationto be used.In cases where the angiography images are too dark, e.g. extremely narrow pupils, or in some late stages where there is avery low level of fluorescence, the use of the ART Mean function will allow you to generate excellent images.9

The following (Fig. 25-29) is a general flow-chart for the acquisition of FA images. Actual time intervals vary depending onpathology. This does not include peripheral images which demand more time. It is possible to withhold a small amount ofthe dye at the initial stage and inject it when you are ready to document the periphery, which will result in higher qualityimages. The earliest images are taken either as a movie or in rapid succession, one every 1-4 seconds, during the dye-arrivalstages, until the veins are full.20 seconds1 minute3 minutes4 minutes8 minutesFig. 25Fig. 26Fig. 27Fig. 28Fig. 29FAAngiograms can unsually be recorded up to 12-15 minutes with fundus cameras, but the SPECTRALIS HRA OCT can alsorecord excellent images at much later stages. Currently there are only few diagnosis that require very late images, after20-30 minutes, such as in cases of suspected optic nerve head edema or suspected tumors.Stereo images can be taken during fluorescein angiography. They are most instructive in cases of e. g. edema, ICCS, PED.6. Indocyanine green angiography (ICGA)Acquiring ICG angiography images is similar to fluorescein angiography technique.Quick Tips: ICGANote: Acquisition of the early and late ICGA images might require specialattention. Acquire movies of early stages, thendelete if not neededDuring the early stages of the dye arrival in ICGA, the images tend to be extremlybright, unless the illumination is reduced accordingly. In the case of ICGA, it isstrongly recommended that the laser intensitiy is reduced to 25 % (Fig. 30) beforethe dye is injected. Remember to return the intensity to 100 % after 2-3- minutes. During the early stage pay specialattention to the brightness adjustment. Reduce laser intensity to 25-50% toacquire the early stages and return itto 100 % after ca. 2-3- minutes. Use ART Mean function for late / darkimages.As in FA, the early stages of the dye arrival are both crucial and difficult to acquire. There are many applications, where amovie of the early stage is used as standard application. This demands a close attention to the illumination aspects of theimage. There are many protocols for acquiring the ICGA images all according to the instistution and the diagnosis. Thefollowing is a rough guide, but it is always best to review the patient chart and ask for guidance when in doubt.ICGAFig. 31Fig. 30: ICG intensitiy reduced to 25 %10Fig. 32Movie mode allows obtaining earliest possible angiographyimages.

3-5 minutes7-10 minutes14-17 minutes20-22 minutes25-plus minutesICGAFig. 33Fig. 34Fig. 35Fig. 36Fig. 37In case where the late stage images seem to be dark or lacking in information, use the ART Mean function (see chapterMean Images). Stereo images may be acquired at any stage (see chapter Stereo Imaging).7. Optical Coherence Tomography (OCT)An OCT scan with SPECTRALIS HRA OCT is always combined with a reflectance or angiography image. The followingmodes are available in combination with OCT:OCTIRBAFBRMColorFAICGAMEAN4444444Movie Stereo Tomo Comp8888WFOUWF88WFO Wide Filed Lens / UWF Ultra-Widefield Angiography ModuleCheckbox for perfect OCT images Keep the patient’s forehead leaned against the forehead support. Patient should blink regularly, since maintaining a good tear film is important for OCT image quality. In cases where the patient suffers from dry eye, or when the cornea cannot be kept moist enough by blinking alone, artificial tears may be administered.Try to maintain an evenly-illuminated, well-focused fundus image, as well as a high-quality OCT scan. Sometimesthe fundus image quality needs to be compromised to some extend, if it provides a better OCT scan.OCT image shows maximum contrast and quality if placed in the Sweet Spot (Fig. 38-40).Select the scan pattern and place it at the desired position.Always activate ART Mean function when performing an OCT scan.Fig. 38: OCT scan within the SweetSpotFig. 39: OCT scan below the SweetSpot - camera too far away from thepatient’s eyeFig. 40: OCT scan upside down - camera too close to the patient’s eye11

Note: The larger the volume scan and the higher the densitiy of the scan, the more time it takes to scan. Adjustingthe size of the volume scan to the circumference of the pathology saves time and data storage. For a higher resolution with more details, such as macular pathologies, the volume scan should be reduced to the size of the pathology and the density increased in order to obtain the maximum amount of information over a short scan period.Note: Depending on the resolution mode (High Resolution oder HighSpeed) the streching in y-direction ranges from 1.5 to 3.0 times theoriginal size.Fig. 41: Touch panel enabled OCT volumescanTips und tricks for acquisition of myopic eyes In cases of myopic, long eyes, or deep set eyes, a good fundus image might be visible, but no OCT scan appears inthe OCT acquisition window. This can be compensated by using the corresponding eye-length button in the acquisition window.If the OCT scan is tilted, move the joystick slightly left / right (horizontal scan) or up / down (vertical scan). Reducing the scan-length helps to avoid imaging the tilted or curved parts of the scan. Patients with more than -12 D should wear contact lenses during the examination. Fig. 42: Curved OCT scan as result of high myopiaNote: Myopic Lens function is not available for OCT imaging. It is especially important for eyes with more than-12 D myopia to use contact lenses (see chapter High Myopia Compensation).12

Tips und tricks for acquisition of astigmatism eyes In astigmatic eyes often good scans can only be achieved by turning the scan at a particular angle.In these cases change the angle of the scans into the optimal direction.Fig. 43: Tilted OCT scan as a result of high astigmatismFig. 44: Straight OCT scan by changing scan directionEnhanced Depth Imaging (EDI) - OCTEDI is an imaging module which allows deeper lying structures to be displayed more clearly in the OCT scan.The contrast of the follwing structures is optimized with EDI-OCT: outer retinal layers, choroid, lamina cribrosa.EDI is available for all scan pattern.Checkbox for perfect EDI-OCT images Keep the patient’s forehead leaned against the forehead support. Patient should blink regularly, since maintaining a good tear film is important for OCT image quality. In cases where the patient suffers from dry eye, or when the cornea cannot be kept moist enough by blinking alone, artificial tears may be administered.Try to maintain an evenly-illuminated, well-focused fundus image, as well as a high-quality OCT scan. Sometimesthe fundus image quality needs to be compromised to some extend, if it provides a better OCT scan.OCT image shows maximum contrast and quality if placed in the Sweet Spot (Fig. 45).Select the scan pattern and place at the desired position.Always activate ART Mean function when performing an OCT scan.Fig. 45: EDI-OCT image13

OCT Follow-Up ExaminationOCT images can be repeated on exactly the same location of the fundus via theAutoRescanTM function. To do a follow up examination, an OCT thumbnail mustbe right clicked with the mouse and „Progression“ and “Set Reference“ must beselected to define the image as baseline image. To place the scan new on the sameposition of the fundus, the scan must be selected via „Follow-Up“ button in theacquisition window. Follow-up examinations can be executed on various devicesin different modes. All OCT scan pattern can be specified as a reference for follow- up examinations. It is possible to combine all OCT acquisition modes as anautomatically aligned base and follow up examination for software versions 5.1and up, such as FA OCT or a BAF OCT defined as a baseline examination andthe follow-up exam executed in IR OCT mode.Quick Tips: Follow-Up examination Define reference exam. Fundus image evenly-illuminated andfocused. Selecting scan via „Follow-Up“-functionCheckbox for perfect Follow-Up Examinations The green frame on the fundus image shows the position of the patients head relative to the initial examination. The green frame can be adjusted by having the patient slightly moving his eyes or head. As soon as the reference image is selected (Fig. 39), the active eye tracking automatically starts and the trackingtime begins. Due to the fact that there is a limit on how long each eye can be tracked, it is recommended that thefundus image first be evenly-illuminated and then the reference image could be selected to perform a follow upexamination.Fig. 46: Select reference image14Fig. 47: Tilted follow-up examination

Scan Planning ToolThe Scan Planning Tool allows to define locations in a cSLO image where an OCT scan should be taken at a later time andto preselect a requested fundus image mode. The selected scan location and pattern is saved to the database. Each Spectralissystem can now automatically perform an OCT scan as planned in the cSLO image.Note: The software „Scan Planning Tool“ isno component of the standard delivery ofthe SPECTRALIS HRA OCT and must bebought seperatly.Fig. 48: Open Scan Planning ToolFig. 49: Scan Planning ToolSteps how to use the Scan Planning Tool Right click on the cSLO image and select Scan Planning Tool (Fig. 48).Plan the OCT scan and the requested Fundus Image Mode (Fig. 49).Save your selection.The planned scan pattern appears as a yellow overlay on the preview icon (Fig. 50).Perform the OCT scan by selecting the cSLO image from the follow-up window in acquisition mode (Fig. 51).Fig. 50: Yellow scan pattern overlay on the preview iconFig. 51: Select reference examination out of followup window15

8. High MagnificationIt is possible and advisable to take high magnification images (15 ) in the various acquisition modes, but they are mostimpressive in angiography modes. The images are particularly significant in the early stages when there is no obscuringleakage in FA (Fig. 52-54) and the contrast is highest in ICGA. High magnification is used especially in ICGA when tryingto locate a feeder vessel.Note: When selecting high magnification, use High Resolution (HR) mode.Fig. 52: 30 Fig. 53: 20 Fig. 54: 15 9. Wide Field Images (Composite, Wide Field Lens, Ultra-Widefield Lens)Composite ImagesQuick Tips: Manual CompositeComposite images are made up of multiple single 30-degree images (Fig. 55-58),resulting in mosaic, large-field image of the retina (Fig. 59). Their final size depends on the total area covered by the original single images and the software’sability to automatically create the final composite. Following the acquisitionof the individual images, highlight those to be included in the composite andselect „Compute Composite“ from the drop-down menu. Use either single images, movie optionor 3x3 Composite. Acquire overlapping images. Check for double vessels in final image.Quick Tips: Real-time Composite Select „Composite“ on touch panel Use external fixation light only! Activate ART Mean function in the composite mode. Move camera head around and keep livefundus image evenly-illuminated. Save images with „Acquire“FAFig. 55Fig. 56FAFAFig. 5716Fig. 58Fig. 59

Composite images can be created through three various methods:1. The easiest method to create a composite image is by using the „3x3 Composite“. After selecting this function onthe touch panel, images with all internal fixation points will be generated one after the other. After succesfullgeneration, all images are automatically combined. The outer periphery cannot be acquired with this method.Fig. 60: Selecting fixation target2. The real-time composite image is started by selecting „Composite“ on the touch panel and pressing the ART /Sensitivity knob. By moving or pivoting the camera head, the composite image is created and by pressing „Acquire“ afterwards the image is saved (Fig. 61 and 62)Fig. 61: ART composite with 30 Standard lensFig. 62: ART composite with Wide Field Lens3. After acquiring individual images or a movie, the picture or movie is marked and selected with a right-click of „ComputeComposite“. If peripheral regions of the retina are acquired through pivoting of the camera head, it is often necessary toadjust the brightness and the focus. Even under the best conditions and the selection of excellent images, the softwareis sometimes unable to create the anticipated proper image. In this case, the procedure should be repeated with severalother images, for example, newly acquired images. When images from the outer area of the periphery are needed, askthe patient to look in a certain direction or offer a fixed point with help from an external fixation and pivot the camerain the desired direction.Wide Field ImagesWith the SPECTRALIS HRA OCT, it is possible to acquire a singlewide field image, using the 55 Wide Field Lens. This lens is mounted on the camera in place of the standard 30 lens. The acquisitionsare executed in a similar manner, however it shows a larger area ofthe fundus (Fig 63). Important to note is that the working distanceis much shorter than with the 30 standard lens. In addition, OCTand MultiColor images are not available with the Wide Field Lens.Note:- Check the focus after mounting the Wide Field Lens.- OCT acquisition an MultiColor images are not available.- The working distance is much smaller than with the30 Standard Lens.FAFig. 6317

Ultra-Widefield Angiography Module (UWF-Module)The UWF-Module allows to acquire evenly-illuminated, accurate and contrast-rich images even in the outer periphery.The UWF-Module is easily attached to every SPECTRALIS oder HRA 2 camera head. Crosspolarized Infrared reflectanceimages (IR(XP)) and BluePeak blue laser autofluorescence (BAF) images as well as fluorescein- and ICG angiographies canbe acquired with the UWF-Module.To attach the UWF lens, set the focus from the Standard 30 lens to 45 D.Checkbox for perfect IR(XP) and BAF images Set the filter wheel to position „P“ and select IR acqusition mode. There is only a weak reflex in this acquisitionmode. The goal is an evenly-illuminated, well-focused IR(XP) fundus image. (Fig. 64). For BAF images, place the filter wheel at position „A“ and select the acquisition mode IR FA (Abb. 65). For a high quality image, increase the sensitivity and if necessary adjust the focus afterwards.Always acquire images by using the ART Mean function.IR(XP)Fig. 64: Crosspolarized IR (IR(XP))imageFig. 65: left BAF; right IR with large central imageartifactIR BAFNote: IR(XP) appear darker than IR reflectance images and can exhibit a circular shaped polarized artifact. Typcialpolarization effects can occur in the area of the macula through the birefringent properties of the Henle fibers, aswell as diffuse, induced through the calculation properties of the retinal nerve fiber layer.Checkbox for perfect UWF-Angiography To adjust camera need for even illumination and focus use IR(XP) with filter wheel in position „P“. To start the angiography, put the filter wheel in position „A“ and select the desired acqusition mode. Fluorescein and ICG angiograpies as well as simultaneous images (read more in chapter 12) are possible with UWF.When the images appear dark or lose contrast in the late phase, the ART Mean function allows contrast enhancement.ICGAFAFig. 6618Fig. 67

10. Mean ImagesThe mean process dramatically improves the quality of the information inthe images, without introducing an alteration to the original image or addingany distracting electronic ‘noise’. It also does not change the inherent relativecontrast or brightness of the original image, even though the averaged imageis obviously brighter.Quick Tips: Mean Excellent for BAF, BR, improving late images, improving dark images and imagesgenerally lacking in detail. Can be created in several ways (see text). After mean image is generated, multipleoriginals can be deleted, saving space.Mean images can be created in three ways:1. Recommended method: By pressing the Sensitivity / ART knob on the touch panel you can activate the ARTMean function to generate a live mean image online and view it as it is created. Once you are satisfied with theresults, you may save the image (Fig. 68 and 69).2. Select the „Mean“ function from the touch panel. Once the raw images have been saved and you opt to leave the acquisition window, the Heyex

The Heidelberg SPECTRALIS HRA OCT provides a unique combi - nation of retinal angiography and optical coherence tomography. The ability of the SPECTRALIS HRA OCT to automatically maintain the OCT scan at the selected location guarantees the correct a