Eye floaters – those little cobweb-like strings that randomly sail across your vision – can be successfully treated with a laser, according to a new study. Researchers in Boston, Massachusetts used a yttrium-aluminum-garnet (YAG) laser to treat floaters in a small group of patients.
Floaters can appear at any age but become more common after the age of 50. Most floaters are caused by changes in the vitreous – the clear gel that fills the eye and helps to maintain its shape. With age, the vitreous gel becomes more liquid and collagen fibres that form part of the vitreous shrink, forming clumps or strings that can cast shadows on the back of the eye (the retina). It is these clumps and strings that we see as floaters.
Very occasionally, floaters can herald the onset of a serious condition. A sudden change in floaters, especially alongside flashing lights in your vision, can indicate a retinal detachment. This is where the retina – the light sensitive membrane of the eye – separates from the back of the eye, causing sight loss.
Retinal detachment is usually treatable but needs urgent medical treatment. Thankfully, it is relatively rare, affecting about one in 10,000 people each year.
Mostly, though, floaters are harmless – if somewhat annoying. One type of floater is more annoying than others. It is called a Weiss ring.
In the eye, the vitreous is firmly attached to the retina at the optic nerve head (the optic nerve carries sensory information from the retina towards the brain), but, as the vitreous shrinks, it can detach from the optic nerve head, creating a ring-shaped floater (Weiss ring).
Weiss rings tend to be larger than most other floaters and, although most people get used to them, for some people they are a constant nuisance.
Treatment for floaters to date has been relatively limited. For most people, no treatment is necessary either because the floaters settle below their line of vision or because their brain learns to ignore them. For persistent and very troublesome floaters, a surgical procedure to remove the vitreous is sometimes offered. As with all surgery, it carries risks, including a high risk of developing a cataract.
Less invasive procedures, such as the laser treatment used by the researchers in Boston, may also be an option for some patients with bothersome floaters. Ophthalmologists regularly use lasers to treat a range of eye conditions; YAG laser treatment can provide an alternative to vitreous surgery for bothersome floaters.
Although YAG laser treatment is not new, we still aren’t sure that all the reported improvements are due to the treatment itself. It might be that some of the self-reported improvements are due to a placebo effect.
Most studies of YAG laser treatment of floaters have measured improvements in patient symptoms using questionnaires. Questionnaires are themselves vulnerable to the placebo effect because they are inevitably influenced by the feelings or beliefs of the subject. In other words, they are subjective.
Objective and subjective measures of success
The latest study looked at YAG laser treatment for Weiss ring floaters. The patients in this study didn’t know if they were getting a sham treatment (where the laser was covered by a lens reducing the strength of the laser to a level that no treatment was possible) or the actual laser treatment.
As with earlier studies, the researchers used a questionnaire to determine whether the patients felt that their symptoms had improved. Just over half of the patients in the treated group reported an improvement in visual symptoms. A small number in the untreated (sham) group also reported some improvement (possible placebo effect).
The authors of this study, however, also took photographs of the patients’ eyes to assess the floaters objectively before and after the treatment. There was no improvement in the appearance of the floaters on the photographs in the untreated group. In contrast, there was a reduction in the floaters in almost all of the treated patients. These new findings represent objective as well as subjective evidence for the benefit of YAG laser in patients with Weiss ring floaters.
These are encouraging results. Most of us are relatively untroubled by our floaters. For those few people, whose quality of life is significantly affected by the presence of Weiss ring floaters, this study offers new and objective evidence that YAG laser may provide an effective treatment option.