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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Thursday, 18 May 2006
Plenary Session 2
Anterior and External Eye
1.33 OPS Continuing Education Credits
13:00 Introduction By Moderator
Paula F. Morris
John Moran Eye Center, University of Utah
Salt Lake City, Utah, USA

13:05 High-Resolution Slit Lamp Photographs Of The Various Layers Of The Cornea Before And After Lamellar Keratoplasty Surgery
Frank P. J. Smolders, Michel J.W. Zaal, Michiel Dubbelman, Peter J. Ringens
VU University Medical Center
Amsterdam, Noord-Holland, The Netherlands
Purpose: This presentation will demonstrate high-resolution slitlamp photographs of the various corneal layers before and after lamellar keratoplasty.
Materials and Methods: A Zeiss photo-slitlamp unit with a refined slitbeam adjustment, combined with a Nikon D1 camera were used to document corneal structures and tissue opacities. Scheimpflug photography (Topcon SL45) was used to quantify corneal curvature and thickness in order to determine the exact level of the surgical corneal stromal interface.
Results: Images from both photographic systems will be presented and discussed.
Conclusions: Since this photographic technique provides essential data on structure and light transmission of the various corneal layers, high-resolution corneal photography has now evolved into a routine diagnostic procedure in the work-up of keratoplasty patients in our clinic.

13:20 A Novel Approach To Direct Angle Imaging
Leslie D. Mackeen, Ike K. Ahmed
Toronto, Ontario, Canada
Purpose: Photographic documentation of the iridocorneal angle requires effort, skill and patient cooperation to view the normally concealed angle architecture. The RetCam (Clarity Medical Systems Inc, Pleasanton, California) is a wide field contact digital fundus camera used in the management of pediatric retinal diseases. Although the camera was designed to photograph the fundus, it is not limited to this purpose. With technique modification it is possible to effectively and easily document a variety of pathologies affecting the adult iridocorneal angle.
Methods: Patients were imaged supine with topical anaesthetic instilled and a liberal mound of dry eye coupling gel applied on the cornea. The tip of the wide field RetCam lens was immersed in the gel, placed at the limbus and directed towards the opposite angle of the eye. While viewing a dynamic image on a computer monitor, illumination was reduced and focus adjusted.
Results: Angle architecture including the ciliary body band, trabecular meshwork, scleral spur and Schwalbe’s line were easily identified and photographed in normal adults and patients. Pigment assessment, angle grade, and iris profile were readily evaluated in patients with a variety of angle/iris abnormalities including pupil block, plateau iris, angle closure, pigment dispersion, iris lesions, and those with peripheral anterior synechiae. Detailed postoperative images of the trabeculo-Descemet window after non-penetrating glaucoma surgery, internal ostium after trabeculectomy, and tube position after tube-shunt surgery were readily captured. Patients undergoing the imaging felt the technique comfortable and non-invasive.
Conclusions: To our knowledge this is the first method of direct digital angle documentation. This technique significantly enhances the use of the camera as a clinical, educational and research tool providing imaging and appreciation of angle structures that would otherwise be difficult to observe and document.

13:35 Gonio-Imaging Using The CGAL Contact Lens
Steve Thomson
Haag-Streit AG
East Lothian, Scotland
Gonio-Imaging is one of the most challenging missions in Ophthalmic Photography. The Goldman 3-mirror lens was designed for general use in ophthalmic examination and many skilled photographers have produced wonderful images of the anterior eye and iridiocorneal angle.
The CGAL (Roussel & Fankhauser) was conceived primarily to enhance laser treatment in the anterior chamber but many of the design features also improve its imaging ability over that of the 3-mirror.
The author will discuss the advantages of the CGAL and show samples of image quality.
Declaration: The author is an employee of Haag-Streit AG.

13:50 The External Eye Photography Point-Of-Care Cart
Denise Cunningham, Guy Foster
National Eye Institute
Bethesda, Maryland, USA
Purpose: To obtain high quality film or digital images of both eyes together, in addition to the photographer’s skill, a good camera and lens combination coupled with a suitable flash assembly is all that is required. Close-up images of a single eye benefit greatly, however, from the addition of a chin rest which serves to reduce patient movement through head stabilization.
In the past, an adjustable table with a mounted chin rest was utilized for external eye photography but severe space limitations and the low number of external eye photographic procedure performed annually at the National Eye Institute (263) did not justify dedicating a permanent space for this activity. Because it continues to be an important procedure to offer to our physician clients, external eye photography is now performed using a modified point-of care cart as a portable external eye studio.
Materials and Methods: Point-of-care (POC) testing refers to the performance of clinical or laboratory tests outside of the customary setting. A commercially available Anthro® POC cart was purchased and modified for use as a traveling imaging studio. Configured with equipment shelves and the addition of a discarded Haag-Streit chin rest assembly, this height adjustable and compact sized cart has been used extensively since it was introduced into our clinic.
Holes were drilled into the bottom of the cart’s particle board table and the adjustable chin rest was easily attached with two screws. Because the cart was designed for mobility and adjustability, no other modifications were necessary.
Once the chin rest assembly was added, the POC was immediately put into service. Because the cart’s height is easily adjustable, children, adults and wheel chair bound patients have all been successfully photographed using the cart.
Results: The POC cart that was modified with the addition of a chin rest assembly has eliminated the necessity of dedicating a permanent space for external eye photography.
Conclusions: Modifying a commercially available point-of-care cart with a suitable head stabilizing unit will transform a generic medical product into an ophthalmic external eye photography studio.

14:05 Pragmatics of Multicenter ERG Studies
S.G.Coupland
University of Ottawa Eye Institute
Ottawa, ON, Canada
Purpose: Some 16 years ago the International Society for Clinical Electrophysiology of Vision (ISCEV) recommended a basic standardized ERG protocol so that certain ERG responses could be recorded comparably throughout the world.[1] Unfortunately, cooperative multi-center collaboration at normative ERG data collection has proven largely unsuccessful. The primary reasons for this inability to collect multi-center norms lies in differences in ERG recording methodology and in standardized luminance. Differences in ERG recording methods have been addressed through standardized protocols. Differences in standardized luminance is more difficult to deal with. The problem lies in the inherent instability of the light source, the xenon flash tube. Recently, an optoelectronic electrodiagnostic system using light-emitting diode (LED) flash stimulation has become commercially available, with greater precision of luminance control. Herein we describe an international study of the normal ERG using the same ERG protocol conducted at two centers in Peoples Republic of China and in Canada using LED stimulation.
Materials and Methods: 150 eyes from 75 normal Chinese patients aged 20-70 years (mean=38 years) were studied and 125 eyes from 125 normal Canadian patients aged 18-79 years (mean age =39 years) were studied in Canada. Fullfield flash ERGs were recorded according to the ISCEV standard [1] using DTL microconductive thread electrodes draped across the conjunctiva adjacent to the limbal margin. Stimulus presentation was produced by an optoelectronic LED stimulator system. Results. Using multivariate ANOVA there were no significant differences between the Chinese and Canadian groups on peak implicit time of a-wave and b-wave in the isolated Rod response, the Scotopic Maximum ERG, the Photopic (cone) ERG or the 30 Hz flicker. There were significant amplitude differences between Chinese and Canadian groups on the b-wave amplitude of the isolated Rod Response (p<0.03), the Scotopic Maximum ERG (p<0.001), the Photopic (cone) ERG (p<0.001) and the 30 Hz flicker trough-to-peak amplitude (p<0.0001). In all these cases the mean b-wave amplitude of the Chinese group was significantly lower than the Canadian group.
Conclusions: We propose that the observed b-wave amplitude differences observed are due to increased axial length in Chinese eyes as evidenced by increased mean (myopic) refractive error. These findings are consistent with recent studies by Westall et al. using the ISCEV standard who demonstrated decreased b-wave amplitudes with no change in b-wave peak latency in eyes with mild, moderate and high myopia[2]. In conclusion, the use of multicenter normative ERG data collection has revealed striking similarities and consistent predictable differences in electroretinal function of different populations.
[1] Marmor, M. and Zrenner, E. Standard for clinical electroretinography (1994 Update). Doc. Ophthalmol. 1995, 89; 199-210. [2]. Westall, CA et al. Values of electroretinogram responses according to axial length. Doc. Ophthalmol. 2001, 102; 115-130.

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Thursday, 18 May 2006 Plenary Session 2 Anterior and External Eye 1.33 OPS Continuing Education Credits
13:00	Introduction By Moderator Paula F. Morris John Moran Eye Center, University of Utah Salt Lake City, Utah, USA
13:05	High-Resolution Slit Lamp Photographs Of The Various Layers Of The Cornea Before And After Lamellar Keratoplasty Surgery Frank P. J. Smolders, Michel J.W. Zaal, Michiel Dubbelman, Peter J. Ringens VU University Medical Center Amsterdam, Noord-Holland, The Netherlands Purpose: This presentation will demonstrate high-resolution slitlamp photographs of the various corneal layers before and after lamellar keratoplasty. Materials and Methods: A Zeiss photo-slitlamp unit with a refined slitbeam adjustment, combined with a Nikon D1 camera were used to document corneal structures and tissue opacities. Scheimpflug photography (Topcon SL45) was used to quantify corneal curvature and thickness in order to determine the exact level of the surgical corneal stromal interface. Results: Images from both photographic systems will be presented and discussed. Conclusions: Since this photographic technique provides essential data on structure and light transmission of the various corneal layers, high-resolution corneal photography has now evolved into a routine diagnostic procedure in the work-up of keratoplasty patients in our clinic.
13:20	A Novel Approach To Direct Angle Imaging Leslie D. Mackeen, Ike K. Ahmed Toronto, Ontario, Canada Purpose: Photographic documentation of the iridocorneal angle requires effort, skill and patient cooperation to view the normally concealed angle architecture. The RetCam (Clarity Medical Systems Inc, Pleasanton, California) is a wide field contact digital fundus camera used in the management of pediatric retinal diseases. Although the camera was designed to photograph the fundus, it is not limited to this purpose. With technique modification it is possible to effectively and easily document a variety of pathologies affecting the adult iridocorneal angle. Methods: Patients were imaged supine with topical anaesthetic instilled and a liberal mound of dry eye coupling gel applied on the cornea. The tip of the wide field RetCam lens was immersed in the gel, placed at the limbus and directed towards the opposite angle of the eye. While viewing a dynamic image on a computer monitor, illumination was reduced and focus adjusted. Results: Angle architecture including the ciliary body band, trabecular meshwork, scleral spur and Schwalbe’s line were easily identified and photographed in normal adults and patients. Pigment assessment, angle grade, and iris profile were readily evaluated in patients with a variety of angle/iris abnormalities including pupil block, plateau iris, angle closure, pigment dispersion, iris lesions, and those with peripheral anterior synechiae. Detailed postoperative images of the trabeculo-Descemet window after non-penetrating glaucoma surgery, internal ostium after trabeculectomy, and tube position after tube-shunt surgery were readily captured. Patients undergoing the imaging felt the technique comfortable and non-invasive. Conclusions: To our knowledge this is the first method of direct digital angle documentation. This technique significantly enhances the use of the camera as a clinical, educational and research tool providing imaging and appreciation of angle structures that would otherwise be difficult to observe and document.
13:35	Gonio-Imaging Using The CGAL Contact Lens Steve Thomson Haag-Streit AG East Lothian, Scotland Gonio-Imaging is one of the most challenging missions in Ophthalmic Photography. The Goldman 3-mirror lens was designed for general use in ophthalmic examination and many skilled photographers have produced wonderful images of the anterior eye and iridiocorneal angle. The CGAL (Roussel & Fankhauser) was conceived primarily to enhance laser treatment in the anterior chamber but many of the design features also improve its imaging ability over that of the 3-mirror. The author will discuss the advantages of the CGAL and show samples of image quality. Declaration: The author is an employee of Haag-Streit AG.
13:50	The External Eye Photography Point-Of-Care Cart Denise Cunningham, Guy Foster National Eye Institute Bethesda, Maryland, USA Purpose: To obtain high quality film or digital images of both eyes together, in addition to the photographer’s skill, a good camera and lens combination coupled with a suitable flash assembly is all that is required. Close-up images of a single eye benefit greatly, however, from the addition of a chin rest which serves to reduce patient movement through head stabilization. In the past, an adjustable table with a mounted chin rest was utilized for external eye photography but severe space limitations and the low number of external eye photographic procedure performed annually at the National Eye Institute (263) did not justify dedicating a permanent space for this activity. Because it continues to be an important procedure to offer to our physician clients, external eye photography is now performed using a modified point-of care cart as a portable external eye studio. Materials and Methods: Point-of-care (POC) testing refers to the performance of clinical or laboratory tests outside of the customary setting. A commercially available Anthro® POC cart was purchased and modified for use as a traveling imaging studio. Configured with equipment shelves and the addition of a discarded Haag-Streit chin rest assembly, this height adjustable and compact sized cart has been used extensively since it was introduced into our clinic. Holes were drilled into the bottom of the cart’s particle board table and the adjustable chin rest was easily attached with two screws. Because the cart was designed for mobility and adjustability, no other modifications were necessary. Once the chin rest assembly was added, the POC was immediately put into service. Because the cart’s height is easily adjustable, children, adults and wheel chair bound patients have all been successfully photographed using the cart. Results: The POC cart that was modified with the addition of a chin rest assembly has eliminated the necessity of dedicating a permanent space for external eye photography. Conclusions: Modifying a commercially available point-of-care cart with a suitable head stabilizing unit will transform a generic medical product into an ophthalmic external eye photography studio.
14:05	Pragmatics of Multicenter ERG Studies S.G.Coupland University of Ottawa Eye Institute Ottawa, ON, Canada Purpose: Some 16 years ago the International Society for Clinical Electrophysiology of Vision (ISCEV) recommended a basic standardized ERG protocol so that certain ERG responses could be recorded comparably throughout the world.[1] Unfortunately, cooperative multi-center collaboration at normative ERG data collection has proven largely unsuccessful. The primary reasons for this inability to collect multi-center norms lies in differences in ERG recording methodology and in standardized luminance. Differences in ERG recording methods have been addressed through standardized protocols. Differences in standardized luminance is more difficult to deal with. The problem lies in the inherent instability of the light source, the xenon flash tube. Recently, an optoelectronic electrodiagnostic system using light-emitting diode (LED) flash stimulation has become commercially available, with greater precision of luminance control. Herein we describe an international study of the normal ERG using the same ERG protocol conducted at two centers in Peoples Republic of China and in Canada using LED stimulation. Materials and Methods: 150 eyes from 75 normal Chinese patients aged 20-70 years (mean=38 years) were studied and 125 eyes from 125 normal Canadian patients aged 18-79 years (mean age =39 years) were studied in Canada. Fullfield flash ERGs were recorded according to the ISCEV standard [1] using DTL microconductive thread electrodes draped across the conjunctiva adjacent to the limbal margin. Stimulus presentation was produced by an optoelectronic LED stimulator system. Results. Using multivariate ANOVA there were no significant differences between the Chinese and Canadian groups on peak implicit time of a-wave and b-wave in the isolated Rod response, the Scotopic Maximum ERG, the Photopic (cone) ERG or the 30 Hz flicker. There were significant amplitude differences between Chinese and Canadian groups on the b-wave amplitude of the isolated Rod Response (p<0.03), the Scotopic Maximum ERG (p<0.001), the Photopic (cone) ERG (p<0.001) and the 30 Hz flicker trough-to-peak amplitude (p<0.0001). In all these cases the mean b-wave amplitude of the Chinese group was significantly lower than the Canadian group. Conclusions: We propose that the observed b-wave amplitude differences observed are due to increased axial length in Chinese eyes as evidenced by increased mean (myopic) refractive error. These findings are consistent with recent studies by Westall et al. using the ISCEV standard who demonstrated decreased b-wave amplitudes with no change in b-wave peak latency in eyes with mild, moderate and high myopia[2]. In conclusion, the use of multicenter normative ERG data collection has revealed striking similarities and consistent predictable differences in electroretinal function of different populations. [1] Marmor, M. and Zrenner, E. Standard for clinical electroretinography (1994 Update). Doc. Ophthalmol. 1995, 89; 199-210. [2]. Westall, CA et al. Values of electroretinogram responses according to axial length. Doc. Ophthalmol. 2001, 102; 115-130.