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Ophthalmic cell-phone imaging system: a costless imaging system
Correspondence
Ophthalmic cell-phone imaging system: a costless imaging system Imaging is an important procedure for various purposes, including teaching, documentation, patient education, assessing disease progression, among others. Ophthalmic imaging has changed dramatically since the 1960s, and increasingly complex technologies are now available. Arguably, the greatest changes have been the development of the digital camera and improvements in the data collection speed, processing power, and storage of electronic data.1 These technological advances have improved the quality of images but, at the same time, have increased costs as well. The anterior segment is usually imaged using slit-lamp imaging systems. However, slit-lamp imaging systems cost up to US $15 000 and are therefore not widely used in countries such as India. Because many private practitioners do not use this system, the technology has not advanced. Less expensive alternatives to slit-lamp imaging, such as a digital camera system, have been sought by innovative doctors; for example, Daljit Singh2 used an SLR camera, Kwan3 used a Nikon Coolpix 950 (Nikon, Japan), and Fogla and Rao4 used a Nikon Coolpix 995 (Nikon, Japan). Several other digital camera accessories, including photo adapters, coupling devices, and so on, have also been previously described.5,6
However, there are a number of disadvantages of using digital cameras for slit-lamp imaging: The system must be carried, hardware modifications to the slit lamp are necessary, and a computer system to transfer the images to the patient is required. In this article, an imaging device consisting of a cell phone that is portable, requires no hardware modifications, and can wirelessly transfer the data is described. A Motorola A1600 (Motorola, USA), which has a 3 MP camera with a resolution of 1536 2048 pixels, was used. This camera gives good images of the anterior segment, and we can even obtain optic disc and angle images. Most important, the device is portable, and the images can be transferred wirelessly to the patient’s cell phone using Bluetooth. A Sony Xperia S Phone with a 12 MP camera and a resolution of 4000 3000 pixels was also used (Sony, Japan). The imaging technique used remained the same. The increased resolution does not have much added advantage.7 Pixel resolution is important only when making large printouts is desired.8 Because the current system is designed to be primarily paperless, the clarity of image as seen on a computer screen or on a cell-phone screen does not depend on the number of pixels. The uniocular imaging procedure is performed in a darkened room for a better contrast. The lesion is focused with the necessary slit-lamp adjustments depending on the
Fig. 1 — External photography and lids.
CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
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Correspondence
Fig. 2 — Conjunctiva and cornea.
Fig. 3 — Anterior chamber and iris.
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CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
Correspondence
Fig. 4 — Lens and vitreous.
type of lesion. Diffuse light is used for large lesions like a pinguecula and pterygium, whereas a slit beam is used for corneal and lens sections, and retroillumination is used for media opacities. The illumination intensity of the slit lamp is lowered to reduce the dazzling light reflex. The lesion can be seen uniocularly through any of the objectives, but low magnification (1) is initially used. The observer’s eye is then replaced by the camera, and the image is shown on the cell-phone screen. Minor focusing adjustments are made with micromovements of the joystick. Once the image is focused, it is acquired after the click of a button and then saved and stored on the phone’s memory card. After saving the desired number of images (a 4-GB memory card can store more than 5000 images), a highmagnification (10) image is then acquired. Almost the same technique is used for the disc images, but the slit-lamp illumination is not as low, and the slit
height and width are reduced to 3 to 5 mm. Thus, a small rectangular illumination is used to reduce the dazzling light reflex, which will have a washout effect on the image. A 10 magnification is used. The disc can be focused uniocularly with 90 D or contact lens biomicroscopy (CLB), but it is easier with CLB because the eye is stabilized. The cell phone is then placed over the eyepiece to view the image, and the image is acquired once it is focused. Acquiring retinal and disc images using a 20-D lens, without the help of a slit lamp or an indirect ophthalmoscope, is also possible and is currently being studied. The procedure is the same for acquiring videos. Once the lesion is focused on the screen, the video recording is started on the cell phone. Then the phone is placed over the eyepiece, and the joystick is moved as required. The images can be transferred between phones via Bluetooth. Once the cell phones recognize each other,
CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
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Correspondence
Fig. 5 — Disc, gonio, retro illumination, and other media.
the image is sent, and the patient receives the image of his or her eye pathology and can make a printout if needed. The images should be periodically (e.g., once a week) transferred to a separate folder on a computer and deleted from the phone memory to maintain free space on the phone. The image quality can be improved using Microsoft Picture Editor (or Picture Manager in Office 2010).9 First, right-click on the image and open the image in the program. Then, select the “thumbnail view” option from the toolbar on the left-hand top side of the screen to display all images. The images can then be selected and autocorrected
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simultaneously using the “autocorrect” function and then saved. Photoshop can also be used to further improve the image by removing noise, increasing sharpness, and so on. In addition to slit-lamp imaging, cell-phone cameras can also be used to take images of computed tomographic or magnetic resonance imaging scans, which would be useful to create case presentations. The device can also be used like a scanner to take snapshots of important parts of a textbook or a journal, instead of writing out the information in a notebook. The examples for various images are in (Figs. 1–5).
CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
Murali Mohan Gurram Kamineni Hospitals
Correspondence REFERENCES 1. Bennett TJ, Barry CJ. Ophthalmic imaging today: an ophthalmic photographer’s viewpoint—a review. Clin Experiment Ophthalmol. 2009;37:2-13. 2. Singh D. Slit lamp photography of the eye. Indian J Ophthalmol. 1976;24:33-5. 3. Kwan A. A simple slit lamp digital photographic system. Eye News. 2000;6:18-21. 4. Fogla R, Rao SK. Ophthalmic photography using a digital camera. Indian J Ophthalmol. 2003;51:269-72. 5. Patel NA. “Photoadaptor for ocular photography” a new design. Indian J Ophthalmol. 1984;32:317-9. 6. Venkatesh R. Letter. Indian J Ophthalmol. 2004;52:84-5.
7. Ken Rockwell. The megapixel myth. www.kenrockwell.com/tech/ mpmyth.htm. Accessed August 5, 2013. 8. Digital Photo Secrets. Do more Megapixels mean better photo quality? www.digital-photo-secrets.com/tip/333/do-more-megapixelsmean-better-photo-quality/. Accessed August 5, 2013. 9. Crop or edit multiple pictures at once in Picture Manager http://office.microsoft.com/en-in/help/crop-or-edit-multiple-picturesat-once-in-picture-manager-HA001077145.aspx?CTT=1. Accessed August 5, 2013. Can J Ophthalmol 2013;48:e135–e139 0008-4182/13/$-see front matter & 2013 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcjo.2013.06.007
CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
e139
Ophthalmic cell-phone imaging system: a costless imaging system Imaging is an important procedure for various purposes, including teaching, documentation, patient education, assessing disease progression, among others. Ophthalmic imaging has changed dramatically since the 1960s, and increasingly complex technologies are now available. Arguably, the greatest changes have been the development of the digital camera and improvements in the data collection speed, processing power, and storage of electronic data.1 These technological advances have improved the quality of images but, at the same time, have increased costs as well. The anterior segment is usually imaged using slit-lamp imaging systems. However, slit-lamp imaging systems cost up to US $15 000 and are therefore not widely used in countries such as India. Because many private practitioners do not use this system, the technology has not advanced. Less expensive alternatives to slit-lamp imaging, such as a digital camera system, have been sought by innovative doctors; for example, Daljit Singh2 used an SLR camera, Kwan3 used a Nikon Coolpix 950 (Nikon, Japan), and Fogla and Rao4 used a Nikon Coolpix 995 (Nikon, Japan). Several other digital camera accessories, including photo adapters, coupling devices, and so on, have also been previously described.5,6
However, there are a number of disadvantages of using digital cameras for slit-lamp imaging: The system must be carried, hardware modifications to the slit lamp are necessary, and a computer system to transfer the images to the patient is required. In this article, an imaging device consisting of a cell phone that is portable, requires no hardware modifications, and can wirelessly transfer the data is described. A Motorola A1600 (Motorola, USA), which has a 3 MP camera with a resolution of 1536 2048 pixels, was used. This camera gives good images of the anterior segment, and we can even obtain optic disc and angle images. Most important, the device is portable, and the images can be transferred wirelessly to the patient’s cell phone using Bluetooth. A Sony Xperia S Phone with a 12 MP camera and a resolution of 4000 3000 pixels was also used (Sony, Japan). The imaging technique used remained the same. The increased resolution does not have much added advantage.7 Pixel resolution is important only when making large printouts is desired.8 Because the current system is designed to be primarily paperless, the clarity of image as seen on a computer screen or on a cell-phone screen does not depend on the number of pixels. The uniocular imaging procedure is performed in a darkened room for a better contrast. The lesion is focused with the necessary slit-lamp adjustments depending on the
Fig. 1 — External photography and lids.
CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
e135
Correspondence
Fig. 2 — Conjunctiva and cornea.
Fig. 3 — Anterior chamber and iris.
e136
CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
Correspondence
Fig. 4 — Lens and vitreous.
type of lesion. Diffuse light is used for large lesions like a pinguecula and pterygium, whereas a slit beam is used for corneal and lens sections, and retroillumination is used for media opacities. The illumination intensity of the slit lamp is lowered to reduce the dazzling light reflex. The lesion can be seen uniocularly through any of the objectives, but low magnification (1) is initially used. The observer’s eye is then replaced by the camera, and the image is shown on the cell-phone screen. Minor focusing adjustments are made with micromovements of the joystick. Once the image is focused, it is acquired after the click of a button and then saved and stored on the phone’s memory card. After saving the desired number of images (a 4-GB memory card can store more than 5000 images), a highmagnification (10) image is then acquired. Almost the same technique is used for the disc images, but the slit-lamp illumination is not as low, and the slit
height and width are reduced to 3 to 5 mm. Thus, a small rectangular illumination is used to reduce the dazzling light reflex, which will have a washout effect on the image. A 10 magnification is used. The disc can be focused uniocularly with 90 D or contact lens biomicroscopy (CLB), but it is easier with CLB because the eye is stabilized. The cell phone is then placed over the eyepiece to view the image, and the image is acquired once it is focused. Acquiring retinal and disc images using a 20-D lens, without the help of a slit lamp or an indirect ophthalmoscope, is also possible and is currently being studied. The procedure is the same for acquiring videos. Once the lesion is focused on the screen, the video recording is started on the cell phone. Then the phone is placed over the eyepiece, and the joystick is moved as required. The images can be transferred between phones via Bluetooth. Once the cell phones recognize each other,
CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
e137
Correspondence
Fig. 5 — Disc, gonio, retro illumination, and other media.
the image is sent, and the patient receives the image of his or her eye pathology and can make a printout if needed. The images should be periodically (e.g., once a week) transferred to a separate folder on a computer and deleted from the phone memory to maintain free space on the phone. The image quality can be improved using Microsoft Picture Editor (or Picture Manager in Office 2010).9 First, right-click on the image and open the image in the program. Then, select the “thumbnail view” option from the toolbar on the left-hand top side of the screen to display all images. The images can then be selected and autocorrected
e138
simultaneously using the “autocorrect” function and then saved. Photoshop can also be used to further improve the image by removing noise, increasing sharpness, and so on. In addition to slit-lamp imaging, cell-phone cameras can also be used to take images of computed tomographic or magnetic resonance imaging scans, which would be useful to create case presentations. The device can also be used like a scanner to take snapshots of important parts of a textbook or a journal, instead of writing out the information in a notebook. The examples for various images are in (Figs. 1–5).
CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
Murali Mohan Gurram Kamineni Hospitals
Correspondence REFERENCES 1. Bennett TJ, Barry CJ. Ophthalmic imaging today: an ophthalmic photographer’s viewpoint—a review. Clin Experiment Ophthalmol. 2009;37:2-13. 2. Singh D. Slit lamp photography of the eye. Indian J Ophthalmol. 1976;24:33-5. 3. Kwan A. A simple slit lamp digital photographic system. Eye News. 2000;6:18-21. 4. Fogla R, Rao SK. Ophthalmic photography using a digital camera. Indian J Ophthalmol. 2003;51:269-72. 5. Patel NA. “Photoadaptor for ocular photography” a new design. Indian J Ophthalmol. 1984;32:317-9. 6. Venkatesh R. Letter. Indian J Ophthalmol. 2004;52:84-5.
7. Ken Rockwell. The megapixel myth. www.kenrockwell.com/tech/ mpmyth.htm. Accessed August 5, 2013. 8. Digital Photo Secrets. Do more Megapixels mean better photo quality? www.digital-photo-secrets.com/tip/333/do-more-megapixelsmean-better-photo-quality/. Accessed August 5, 2013. 9. Crop or edit multiple pictures at once in Picture Manager http://office.microsoft.com/en-in/help/crop-or-edit-multiple-picturesat-once-in-picture-manager-HA001077145.aspx?CTT=1. Accessed August 5, 2013. Can J Ophthalmol 2013;48:e135–e139 0008-4182/13/$-see front matter & 2013 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcjo.2013.06.007
CAN J OPHTHALMOL — VOL. 48, NO. 5, OCTOBER 2013
e139