Vitreous floaters are microscopic clumps of collagen fibres in the vitreous that cast shadows on the retina, appearing as floaters. The most common cause of vitreous floaters is posterior vitreous detachment, when the posterior hyaloid face separates from the retina.
Vitreous floaters can be primary or secondary. Primary vitreous floaters originate from the vitreous body. Secondary vitreous floaters originate from outside the vitreous body, generally from proteins, amyloid or cells.
Vitreous floaters do not usually threaten vision and can be managed conservatively. When they do affect vision, treatment options include vitrectomy and vitreolysis with YAG laser.
This procedure aims to improve vision and reduce symptoms by removing or reducing the size of floaters.
The pupil is dilated and anaesthetic eye drops are administered. A specialised contact lens is placed on the cornea. Coaxial illumination is used. A laser microscope focuses on the front surface of the floater and creates short bursts of energy (nanosecond pulses). The laser energy usually starts at a low level, and is increased until it is high enough to break up the floater. The laser is stopped once all visually significant floaters are treated.
YAG laser vitreolysis is done as an outpatient procedure. Depending on the characteristics and numbers of floaters, more than 1 session may be needed.