The origin of life has been plagued by the fundamental obstacle to increasing in complexity summarized by Eigen's 1 paradox: no enzymes without a large genome and no large genome without enzymes ...

Above the tipping point, the slope for RNFL thickness and threshold was 0.03 dB/µm; below the tipping point, the slope was 0.28 dB/µm. The difference was statistically significant ( P < .001).