A new experiment and theoretical finding has gone some way to explain the origins of severe eye diseases and will assist in further tests to eventually assist in the prevention of blindness.
A study that has investigated the mechanical properties of the eyes light sensing cells provided new insight as to what may cause the outer segments to break under pressure. This outer segment is cylindrical which is both unique and is the cause for damage under pressure.
It is believed to be the first theory to explain how the rigidity of the structure of the outer segment can so easily snap and as such is an advancement in our understanding of retinal degenerative diseases.
The outer segment of the eyes photoreceptors consist of discs packed with protein called rhodopsin. This protein is light sensitive. The discs made in the evening differ from those produced in the day which generates a banding pattern. The outer segment can often become destablised due to mutations in the photoreceptors, which causes the cells to die, retinal degeneration and eventual blindness. Until now, it was unclear which structural properties of the outer segment determine its susceptibility to damage.
The study investigated tadpole photoreceptors while introducing them to strong fluid forces.
They found that densely populated bands with high levels of rhodopsin kept a rigid form which made them more susceptible to breakage than low-density bands consisting of less rhodopsin. The investigation helped to find and document that critical force needed to break the outer segment. Refinements of the model is hoped to reveal new ways to stabilize the outer segment that would delay the onset of blindness.