International Conference on Ophthalmic Photography

Organized by
Australian Institute of Medical and Biological Illustration
Japanese Ophthalmic Photographers' Society
Ophthalmic Imaging Association
Ophthalmic Photographers' Society

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Friday, 19 May 2006
Plenary Session 5
Imaging Technology and Applications II
2.00 OPS Continuing Education Credits
10:25 Introduction By Moderator
Angela J. Chappell
Adelaide, South Australia, Australia
10:30 DICOM & Ophthalmology
Colin Clements
King's College Hospital
London, England, UK
DICOM has developed over the last 20 years as the de facto digital radiology image standard. It evolved from the need to be able to store, exchange and display digital images irrespective of the modality, transmission method and display digital images irrespective of the modality, transmission method and display hardware.
Manufacturers and end users collaborated in working groups to set and define standards for particular clinical areas. Working Group 9 is responsible for Ophthalmology standards.
This presentation will give a high level overview of what DICOM is and how it enables digital images to be stored, exchanged and displayed. All the major hardware vendors are represented on Working Group 9.
Vendors of hardware and software for ophthalmic imaging already offer products that are DICOM conformant. An understanding of how hardware and software communicates with centralised storage (PACS) is helpful in evaluating systems.
As medical practice moves from paper to electronic medical records it becomes increasingly important that imaging data is available using common standards designed for medical imaging.
After radiology, ophthalmology is one of the biggest users of digital imaging and therefore DICOM is likely to be a significant development for ophthalmic imaging. Following the presentation delegates will have an understanding of:

Conformance Statements
Information Objects
MetaData
Compression
Transfer Syntax
Presentation States
Hanging Protocols
Standard Display Functions

10:45 The Camera Raw File Format- Why And How To Use It
Richard E. Hackel
Kellogg Eye Center
Ann Arbor, Michigan, USA
Purpose: To explain the camera raw format, and why it is useful in ophthalmic imaging as well as its importance to photography in general. With demonstrations, show the advantages in photographic quality possible by using this format.
Materials and Methods: When a digital camera stores image data in one of the common formats such as JPEG or TIFF, it is actually processing the images to pre-specified values determined by the camera manufacturer. The camera raw format provides access to the image before this manipulation takes place. Some ophthalmic digital imaging vendors have been offering this high degree of image control for fundus photography and fluorescein angiography. More recently, many general photography cameras now offer this option, and this control of image processing can be very useful for anterior segment photography.
Whereas many digital ophthalmic systems uses proprietary software to automatically process the raw format fundus images, there are a number of options for processing the general photographic raw image. Using Adobe Photoshop CS2 and the Adobe DNG raw converter offers a uniform and cross-platform method for managing these digital imaging files, and creating an efficient workflow.
Results: Routine digital fundus imaging in the raw format provides readily available images, that can be re-processed if desired especially with over/under exposure during a fluorescein angiogram. Anterior segment photography can also take advantage of camera raw, although currently there is not a maximally efficient automated method for doing this.
Conclusions: While well exposed images processed in-camera with JPEG can be of very useful quality, using the raw format can extract extra detail when needed.

11:00 Methods For Imaging Feeder Vessels
Thomas M. Clark¹, Igor Kozak¹, Lingyun Cheng¹, Denine E. Cochran², William R. Freeman²
University of California San Diego¹
San Diego, California, USA
Shiley Eye Center²
La Jolla, California, USA
Purpose: To review the methods used in the imaging of feeder vessels prior to and following the use of verteporfin in a phase I/II clinical trial.
Materials and Methods: Feeder vessels were identified by the use of the Heidelberg HRA I and indocyanine green angiography. Dye dosages and angiographic timing were adjusted to provide clinically significant information while assuring that the technique was repeatable.
Results: As the study progressed and at it’s conclusion, analysis showed that this technique provided significant clinical data in the imaging of subfoveal choroidal neovascularization feeder vessels prior to and following treatment.
Conclusions: High speed feeder vessel ICG angiography can demonstrate the efficacy of verteporfin enhanced therapy and shows that it does not cause subfoveal retinal damage.

11:15 Optimizing Image Sensors For Retinal Imaging
Bert Massie
San Ramon, California, USA
Purpose: With CCD sensors and cameras becoming available with up to 39 Million pixels, one must ask “What is the best choice for clinical work?” It is the purpose of this paper to review the technology, optics and clinical reasoning so as to assist photographers and clinicians in making the optimum equipment choice.
Materials and Methods: We have approached this question by evaluating the physics of light imaging, the nature of the retinal image, and issues of performance excluding pixel resolution alone. Subsequently, our theoretical projections were tested using imaging devices of different pixel count.
Results: For most applications, the value of improved resolution from an increased pixel count tops out at about four megapixels for color imaging. Costs of sensors at this level are rapidly coming down, giving prospective buyers outstanding point of value and price. A solid understanding and quantitative confirmation regarding optimum sensor choices was developed.
Conclusions: It is possible to ‘over-purchase’ pixel count and actually reduce the image quality and its clinical value. There is an optimum pixel count for the eye and current imagers are exceeding this with the result of additional costs to the user as well as reducing the value of the images to patient.

Invited Lecture
11:30 Introduction
Paul R. Montague
University of Iowa
Iowa City, Iowa, USA
11:35 Digital Horizons: You Ain't Seen Nothing Yet
Kenneth W. Boydston
President, MegaVision Inc.
Santa Barbara, California, USA

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Friday, 19 May 2006 Plenary Session 5 Imaging Technology and Applications II 2.00 OPS Continuing Education Credits
10:25	Introduction By Moderator Angela J. Chappell Adelaide, South Australia, Australia
10:30	DICOM & Ophthalmology Colin Clements King's College Hospital London, England, UK DICOM has developed over the last 20 years as the de facto digital radiology image standard. It evolved from the need to be able to store, exchange and display digital images irrespective of the modality, transmission method and display digital images irrespective of the modality, transmission method and display hardware. Manufacturers and end users collaborated in working groups to set and define standards for particular clinical areas. Working Group 9 is responsible for Ophthalmology standards. This presentation will give a high level overview of what DICOM is and how it enables digital images to be stored, exchanged and displayed. All the major hardware vendors are represented on Working Group 9. Vendors of hardware and software for ophthalmic imaging already offer products that are DICOM conformant. An understanding of how hardware and software communicates with centralised storage (PACS) is helpful in evaluating systems. As medical practice moves from paper to electronic medical records it becomes increasingly important that imaging data is available using common standards designed for medical imaging. After radiology, ophthalmology is one of the biggest users of digital imaging and therefore DICOM is likely to be a significant development for ophthalmic imaging. Following the presentation delegates will have an understanding of: Conformance Statements Information Objects MetaData Compression Transfer Syntax Presentation States Hanging Protocols Standard Display Functions
10:45	The Camera Raw File Format- Why And How To Use It Richard E. Hackel Kellogg Eye Center Ann Arbor, Michigan, USA Purpose: To explain the camera raw format, and why it is useful in ophthalmic imaging as well as its importance to photography in general. With demonstrations, show the advantages in photographic quality possible by using this format. Materials and Methods: When a digital camera stores image data in one of the common formats such as JPEG or TIFF, it is actually processing the images to pre-specified values determined by the camera manufacturer. The camera raw format provides access to the image before this manipulation takes place. Some ophthalmic digital imaging vendors have been offering this high degree of image control for fundus photography and fluorescein angiography. More recently, many general photography cameras now offer this option, and this control of image processing can be very useful for anterior segment photography. Whereas many digital ophthalmic systems uses proprietary software to automatically process the raw format fundus images, there are a number of options for processing the general photographic raw image. Using Adobe Photoshop CS2 and the Adobe DNG raw converter offers a uniform and cross-platform method for managing these digital imaging files, and creating an efficient workflow. Results: Routine digital fundus imaging in the raw format provides readily available images, that can be re-processed if desired especially with over/under exposure during a fluorescein angiogram. Anterior segment photography can also take advantage of camera raw, although currently there is not a maximally efficient automated method for doing this. Conclusions: While well exposed images processed in-camera with JPEG can be of very useful quality, using the raw format can extract extra detail when needed.
11:00	Methods For Imaging Feeder Vessels Thomas M. Clark¹, Igor Kozak¹, Lingyun Cheng¹, Denine E. Cochran², William R. Freeman² University of California San Diego¹ San Diego, California, USA Shiley Eye Center² La Jolla, California, USA Purpose: To review the methods used in the imaging of feeder vessels prior to and following the use of verteporfin in a phase I/II clinical trial. Materials and Methods: Feeder vessels were identified by the use of the Heidelberg HRA I and indocyanine green angiography. Dye dosages and angiographic timing were adjusted to provide clinically significant information while assuring that the technique was repeatable. Results: As the study progressed and at it’s conclusion, analysis showed that this technique provided significant clinical data in the imaging of subfoveal choroidal neovascularization feeder vessels prior to and following treatment. Conclusions: High speed feeder vessel ICG angiography can demonstrate the efficacy of verteporfin enhanced therapy and shows that it does not cause subfoveal retinal damage.
11:15	Optimizing Image Sensors For Retinal Imaging Bert Massie San Ramon, California, USA Purpose: With CCD sensors and cameras becoming available with up to 39 Million pixels, one must ask “What is the best choice for clinical work?” It is the purpose of this paper to review the technology, optics and clinical reasoning so as to assist photographers and clinicians in making the optimum equipment choice. Materials and Methods: We have approached this question by evaluating the physics of light imaging, the nature of the retinal image, and issues of performance excluding pixel resolution alone. Subsequently, our theoretical projections were tested using imaging devices of different pixel count. Results: For most applications, the value of improved resolution from an increased pixel count tops out at about four megapixels for color imaging. Costs of sensors at this level are rapidly coming down, giving prospective buyers outstanding point of value and price. A solid understanding and quantitative confirmation regarding optimum sensor choices was developed. Conclusions: It is possible to ‘over-purchase’ pixel count and actually reduce the image quality and its clinical value. There is an optimum pixel count for the eye and current imagers are exceeding this with the result of additional costs to the user as well as reducing the value of the images to patient.
Invited Lecture
11:30	Introduction Paul R. Montague University of Iowa Iowa City, Iowa, USA
11:35	Digital Horizons: You Ain't Seen Nothing Yet Kenneth W. Boydston President, MegaVision Inc. Santa Barbara, California, USA