Wouldn’t it be nice if an eyeball could be taken from the patient’s head, dissected, observed by the doctor, observed by the patient in enlarged format —no harm done — and the eye is placed back in normal functioning order?
Wouldn’t it be even nicer if, in addition to the general anatomy, we could see intricate tissue layers down to a few hundred microns? That way, the tissue that collects light information that’s passed to the optic nerve and then on to the brain could be dissected out, observed, then just as easily be put back unharmed
The eye camera provides gross structural images, enlarged for nice observation. But the OCT slices the tissue, dissects the retina (total thickness less than 1000-1500 microns) into ten layers with a resolution of 3 microns. This means the cause, nature, structural change, micro-hemorrhaging, and even splitting of 200 micron layers can be observed at a magnified level, easy to observe and discuss.
How can the OCT actually make these bloodless incisions? It’s through a process called tomography, which is the production of layered images of solid structure by the varying difference in which separate layers adsorb or reflect varying wavelengths of electromagnetic energy (light). This is the miracle of laser (light amplification by stimulated emission radiation) technology.
For example, a patient came in for a routine visit with good vision in both eyes. His right eye was normal. His left eye showed a hole developing in the central vision area of the retina (macula). Nothing could be found by direct observation or photography, but we were able to detect the macular condition using OCT.
Another example: sometimes a membrane develops over the macula, or sub-retinal. With OCT, we can see it before it happens, enabling us to manage the condition.
And using OCT, we can observe the change in nerve thickness caused by elevated eye pressures (glaucoma), and then treat the condition based on the computer-analyzed peripheral vision test.
Optical Coherence Tomography is truly a modern medical miracle!