Ocular straylight

Ocular straylight is the unwanted effect of light spreading as seen by human eyes, and caused by the eye itself, not by external factors. It is most easily visualized as the radiation seen spreading from a bright light source against a dark background. The typical practical example is an opposing car with headlights on at night. The disability glare caused by such a situation was found to correspond precisely to the effect of true light.^[1] As a consequence, disability glare was subsequently defined by this true light, called "straylight".^[1]

Individual differences

Straylight can differ considerably between individuals. With aging, the crystalline lens of the human eye causes straylight to become worse.^[2] Lens extraction and artificial lens implantation is an effective treatment.

There are however many more, but less common causes for straylight problems:

Diseases of the cornea, e.g. Fuchs' dystrophy.^[3]
Lack of pigmentation, e.g. albinism.^[4]
Laser refractive surgery, with occasional haze formation.^[5]
Excessive floaters in the vitreous humour.^[6]
Contact lenses.^[7]

References

^ ^a ^b Vos JJ. "Disability glare - a state of the art report". Commission International de l'Eclairage Journal. 1984;3/2:39-53
^ Van den Berg TJTP et al. "Straylight effects with aging and lens extraction". Am J Ophthalmol. 2007;144:358-363
^ Van der Meulen IJ et al. "Quality of vision in patients wtih fuchs Endothelial dystrophy and after DSEK". Arch Ophthalmol 2011
^ Kruijt B et al. "Ocular straylight in albinism". Optom Vis Sc 2011;88:E585-E592
^ Van Bree MC et al. "Straylight values after refractive surgery". Ophthalmology 2011;118:945-953.
^ Mura M et al. "Surgery for floaters". Ophthalmology 2011;118:1894
^ Van der Meulen IJ et al. "Straylight measurement in contact lens wear". Cornea 2010;29:516-522