Retinitis Pigmentosa is a disorder of retinal degeneration It is basically an eye disorder and and affects the cell-rich retina of the eye. It causes destruction of photoreceptor cells and sometimes death of rods and cons causing poor vision and sometimes complete loss.
Sjogren's Syndrome is a disorder of body's auto immune system and this is usually identified due to dry mouth and dry eyes. It usually does not come alone and brings along these two disorders along with it namely rheumatoid arthritis and lupus.