Proposal for New Work Item for WG9 on Addition of an IOD for Ophthalmic Topographic
Image
Introduction.
DICOM WG 9 (Ophthalmology) has determined that a new Information Object Definition (IOD) is
necessary to adequately represent the most commonly used ophthalmic topographic maps and
images for exchange between imaging equipment and workstations. The new IOD will be used with
several types of ophthalmic devices including corneal topographer, wavefront aberrometer, and
techniques which use light and optics to produce topographic images of the anterior portion of the
human eye. Images created may be single frame or multi-frame, and are usually coded with color or
monochrome coding scheme. Ophthalmic topographic imaging requires very specific and detailed
identification of the equipment used and related acquisition attributes for proper interpretation of the
images.
It is proposed that the DICOM Committee approve a Work Item for the development of a new
supplement tentatively titled An IOD and SOP Class for Ophthalmic Topographic Image.
Limitations of Current Standard.
Like other topographic maps, the ophthalmic topographic images allow physicians to form a “3-D”
perspective of the measured ocular surface, and are used for clinical diagnostic and monitoring
purposes. As ophthalmology and optometry offices shift to a paperless environment, WG9
(Ophthalmology) has identified the need for a compatible DICOM IOD for the exchange of
ophthalmic topographic maps and images. WG9 evaluated the existing DICOM IODs and did not
find any that represents adequately these topographic image types:
1. Ophthalmic topographic images are generated by special ophthalmic equipment using a wide
variety of light sources, lens systems, and digital camera types. The viewer of topographic images
needs equipment and parameter descriptions for proper interpretation. The General Equipment
Module needs to be supplemented by an ophthalmic equipment module for adequate identification.
2. The interpretation of topographic images is highly correlated with the measurement parameters
that determine the curvature and refractive status of the anterior portion of the human eye. The
highly specialized relationship between topographic images with measurement parameters needs to
be defined explicitly.
Description of Proposal.
WG 9 will define the requirements for and write a new IOD which will most likely include
specialized Series, Equipment, and Image Modules. An important part of this effort will be to agree
on Image Types, define the relationships of images with its associated parameters, and sort out the
use of acquisition context and standardized terminology. Consideration will also be given to image
presentation problems.
A meeting was held on March 17, 2006 to start work on the requirements and definitions. A series
of teleconferences will be scheduled for April through July for review and editing. WG 9 would like
to schedule the first review with WG 6 for their August meeting. Subsequent teleconferences will
be scheduled for September through December with the goal of completing a draft for public
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comment by the January 2007 meeting of WG 6. The (aggressive) goal is to have a new DICOM
Supplement approved in a little over one year. WG9 would like to encourage equipment
manufacturers and EMR vendors to experiment with the new IOD as soon as possible.
Parts of Standard Affected.
Part 3 will add the new Ophthalmic Topographic Image IOD
Part 4 will add a new Ophthalmic Topographic Image SOP Class
Part 6 will add a new SOP Class UID and an undetermined number of new attributes
Part 16 will add new codes and possibly new templates – to be determined
Workload.
Working Group 9 has been preparing to develop a new supplement through discussions of
equipment types, data formats, and individual attributes at several past meetings. They have agreed
to dedicate meeting and conference time to complete a supplement for public comment by the end
of this year. About a dozen manufacturers and at least 8 clinical and university representatives have
participated in previous meetings.
Working Group 9 expects to spend 1 full day in meeting, in addition to many hours of individual
effort in preparation to complete a first draft IOD. Following this initial meeting, an editor will be
appointed to draft a supplement for review by WG 9 members. The intent is to retain a consultant to
provide technical assistance during the draft and review process.
It is expected that total review time by WG 6 will be minimal because the proposed supplement will
leverage familiar structures and format without major innovative concepts. It is estimated a first
reading by Working Group 6 will take about 3 hours of meeting time, and a final review about 2
hours each of 2 times.
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