|Year : 2015 | Volume
| Issue : 1 | Page : 43-45
Digital camera in ophthalmology
Ashish Mitra, Elesh Jain, Alok Sen, Shubhi Tripathi
Sadguru Netra Chikitsalaya, Chitrakoot, Madhya Pradesh 210204, India
|Date of Web Publication||30-Sep-2015|
Sadguru Netra Chikitsalaya, Jankikund, Chitrakoot, Madhya Pradesh 210204
Source of Support: Nil, Conflict of Interest: None declared.
Ophthalmology is an expensive field and imaging is an indispensable modality in ophthalmology; and in developing countries including India, it is not possible for every ophthalmologist to afford slit-lamp photography unit. We here present our experience of slit-lamp photography using digital camera. Good quality pictures of anterior and posterior segment disorders were captured using readily available devices. It can be a used as a good teaching tool for residents learning ophthalmology and can also be a method to document lesions which at many times is necessary for medicolegal purposes. It's a technique which is simple, inexpensive, and has a short learning curve.
Keywords: Anterior segment, digital camera, ophthalmic photography, posterior segment, slit.lamp photography
|How to cite this article:|
Mitra A, Jain E, Sen A, Tripathi S. Digital camera in ophthalmology. Digit Med 2015;1:43-5
| Introduction|| |
Photography is an indispensable modality in ophthalmology. But for every ophthalmologist to afford slit-lamp photography unit is not always possible, especially in developing countries including India. Many articles over the past few years have described imaging of anterior segment and few articles have reported posterior segment imaging with use of digital camera and use of adaptor/brachets.,, We describe use of a plastic sleeve and a thin copper wire (cost less than 1$) to capture anterior and posterior segment photograph as brachets and sleeve are customized and not available readily.
The aim of using this modality was to answer three specific questions:
- Does digital camera actually work well when used on a slit lamp?
- Could it be a replacement for slit-lamp photography unit?
- Is it possible to document posterior segment pathology using a slit lamp and +90 D lens?
| Camera and Technique|| |
The camera we used was Canon SD 700 Power Shot. It is a 6.0-megapixel camera with a wide viewing angle 2.5" liquid crystal display (LCD) screen.
External photographs of the eye
Its zoom can be adjusted from 35 to 140.0 mm (focal length). All digital cameras have an auto-focus system and flashlight on the "on" mode and the object of interest viewed on the LCD monitor. The Canon Power Shot uses the AiAF system that automatically attempts to select the best focus. For clinical photography, AiAF should be turned off and the camera set to "center focus". "Center focus" forces the camera to focus only on the center object. This is important, for instance, when a lid lesion is the subject of interest as the AiAF system may focus on the eyelashes instead of the lesion.
For taking extreme close-ups, the macro mode (close-up mode) denoted by flower symbol should be switched on. It denotes image area at minimum shooting distance from the end of the lens and varies from 2 to 40 cm. It allows images to be taken from a short distance. The macro setting provides detailed images of the eye. We found that to ensure proper focus with the PowerShot camera, one should press the shutter button half-way. On pressing the shutter button half-way a green box will appear on the LCD viewfinder when the area of interest is in focus. If a yellow box appears, then the camera should be repositioned until depression of the shutter button half-way down results in a green box. We ensured that all our photographs were taken with good room illumination. Sometimes we also need to switch off the flash and external source of light gives us good quality images.
| Slit-Lamp Photography|| |
For slit-lamp photography, the camera needs to be set to (1) center focus, (2) macro mode, and (3) flash off. While taking photographs, we focused on the desired anterior segment finding with the slit lamp using either the left or right biomicroscope ocular. Through the same eyepiece and using the LCD viewfinder on the camera, center and focus was on the subject by moving the camera away or towards the eyepiece. We found that ideally a spacer between the eyepiece and camera lens can be made, but using a finger works well too and we tried a plastic sleeve over the lens creating a distance of 8 mm from the end of the lens and eyepiece [Figure 1]. With either technique we got good quality pictures.
Again we used to depress the shutter half-way down until the green box appears, indicating that the subject is in focus [Figure 2]. If a yellow box appears, then we used to reposition the camera slightly and depress the shutter half-way down again [Figure 2]. Because digital cameras lack the dynamic range of the eye; however, most anterior segment photographs require an external light source. We used an external illuminator if required for that purpose. With external light source we got quality pictures. We found that pictures and video can also be acquired through the slit lamp [Figure 3]. With the same technique and setting we also captured fundus images and recorded angiography through fundus fluorescein angiography (FFA) unit.
We also tried capturing posterior segment pathology on slit lamp using +90 D lens. An assistant was trained to hold +90 D lens and images of posterior segment were captured. We also tried fixing the +90 D lens with the help of a thin copper wire [Figure 4]. In both the cases we were able to capture images of the posterior segment [Figure 5].
|Figure 5: Posterior segment images using +90D showing subretinal hemorrhages and choroidal rupture|
Click here to view
| Discussion|| |
The technique being simple and cheap can provide ophthalmologists and patients with good quality photographs using a digital camera and a slit lamp. Any digital camera with some practice and a short learning curve can be a replacement for slit-lamp photography unit. Pictures taken can be shown to the patients to explain their disease entity to them. Even the residents can take pictures for academic purpose. One can also try and capture video of anterior segment and posterior segment with little practice. So to conclude digital camera can take good quality photographs from slit lamp of both anterior and posterior segments with readily available devices and it can be a simple tool which is affordable by all and definitely makes our job easy.
| References|| |
Fogla R, Rao SK. Ophthalmic photography using a digital camera. Indian J Ophthalmol 2003;51:269-72.
McLean CJ, Tossounis CM, Saleh GM. Camera adapter for anterior segment slitlamp photography. J Cataract Refract Surg 2006;32:1889-91.
Patalano SM, Salehi-Had H, Patalano VJ 2nd
. Low cost digital photography of anterior and posterior segments. J Cataract Refract Surg 2010;36:1051-3.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]