Health - Retina cell growth measured by lasers

(Image: Omikron/SPL)

THE cone cells that help give us our colourful view of the world have been recorded growing in real-time in a living person's eye.

Cone cells in the retina each carry a stack of membranous discs: as they grow they shed older discs and generate new ones. An imbalance in the process can lead to blindness.

Ravi Jonnal and colleagues at Indiana University in Bloomington have found a way to measure cone-cell growth by reflecting part of a laser beam off the cells within the eye of a healthy volunteer. Another part of the laser beam is reflected off a mirror a set distance away.

When the two beams recombine, the pattern of interference allows the team to work out the position of each disc in the cone cell. Taking measurements over several hours allowed Jonnal's team to track each disc, revealing that the cells grow at roughly 150 nanometres each hour (Biomedical Optics Express, DOI: 10.1364/boe.3.000104).

Fred Fitzke of University College London is impressed. "This could lead to major advances in preventing the progress of some of the leading causes of blindness," he says.

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