One of the greatest privileges of being an optometrist is to be able to look at our patient’s eyes in great detail, including right through the pupil to the back of the eye. The eye is an amazing organ with many intricate details which we routinely examine as part of our eye examinations and so often we take our sight for granted, but many may wonder what are we actually looking at back there when we examine the eyes.
Examining the eyes isn’t as scary as some may think, especially given the popular myth in the late 19th and early 20th centuries that the eyes somehow recorded what we saw and that if you photographed the eyes of a dead person you could see the last thing they saw (http://en.wikipedia.org/wiki/Optography and http://www.college-optometrists.org/en/college/museyeum/online_exhibitions/eye/optography.cfm). This popular concept was used as a plot device in some fiction of the time and was even employed as an investigative technique for some actual forensic investigations.
|Our digital retinal camera|
At Ocean Optometry we are pleased to include retinal photography as part of our standard comprehensive
eye examination* and we use a Nikon DSLR camera back mounted on a digital retinal camera to capture the images even before you see Dr McGinty or Dr Wilson. These images are seamlessly integrated into your electronic health record at Ocean and will be reviewed with you by our doctors as part of your eye examination.
Here is an example of one of our digital images:
|Digital Retinal Image – Right Eye|
You can clearly see some very important structures in the eye, although on first glance it may resemble more the appearance of Mars or the Sun towards sunset. The salmon pink colour of this photograph shows a nice healthy retina, with the blood vessels overlying the retina. The lighter/thinner blood vessels are the arteries, which supply oxygenated and nutrient rich blood to the tissues. The darker/thicker vessels are the veins which take the blood back to the heart. The vessels branch out from a single point, with smaller and smaller branches, nicely resembling a tree in appearance.
In the lighter pink areas, almost yellow, the retina is light enough that the underlying blood vessel structure is visible. This is from the white of the eye, right round at the back of the eye!
The point where the blood vessels enter and leave is also the point where the optic nerve leaves the eye to take the information to the brain about what we are seeing. This is the optic nerve head or the optic disc and creates the natural blind spot in the eye which we all have. Careful examination of the optic nerve head is very important to help to assess for the presence of glaucoma. Using digital photographs as part of our eye examination allows for careful comparison in appearance of the optic nerve head between visits to help detect change over time.
Central in the picture is a darker area, called the macula. The macula is the area of greatest sensitivity of the retina, it has the highest density of light receptive cone cells present, the highest density of pigment underlying the macula and has a very rich supply of nutrients provided through the underlying vessel structure. Unfortunately, if this area is damaged the impact on our quality of vision can be significant and this is why regular assessment to look for signs of diseases such as Macular Degeneration is important.
One final feature we often get asked about when we are discussing the retinal images is “what is that bump/lump in the top right corner?”. This is a historical feature in retinal photographs and is always in the top right corner as a way of saying “This way up!”. Prior to digital photography, retinal photographs relied upon either 35mm slide film of polaroid film to capture the images, once printed a photograph could be rotated and with slide, flipped even, which could lead to confusion over the area of the eye you were looking at or if you were looking at a right or a left eye. So don’t worry about the bump, we want it to be there!
* There is a $25 co-pay for digital retinal photography for MSI paid eye examinations.
|Quality ensured using our Nikon camera|