Step one. Choose a lens with enough depth to clear the cornea entirely. Scleral lenses by definition do not touch the cornea. If you put a lens on the eye that touches the cornea, it is simply not deep enough. Moving to a lens with greater depth will eventually lead to a lens that clears the cornea entirely.
Guide. An electroencephalogram (EEG) is a test that measures and records the electrical activity of your brain. Special sensors (electrodes) are attached to your head and hooked by wires to a computer. The computer records your brain 's electrical activity on the screen or on paper as wavy lines. Certain conditions, such as seizures, can be seen by the changes in the normal pattern of the brain 's electrical activity.
A PET or SPECT scan can map the brain by measuring the distribution and density of neurotransmitter receptors in certain areas. Use of this technology has led to a better understanding of which brain regions regulate mood and how other functions, such as memory, may be affected by depression. Areas that play a significant role in depression are the amygdala, the thalamus, and the hippocampus (see Figure 1).