Patients commonly have a few longstanding vitreous floaters in their vision, or the occasional flash of light (photopsia).
More worrying symptoms include a sudden increase in the number of floaters or a change in their nature, new floaters, acute photopsia, or a visual field defect. The latter suggests retinal detachment.
Risk factors for retinal detachment include high myopia, complicated cataract surgery, trauma, a positive family history, and previous retinal detachment in either eye.
The commonest differential diagnosis of photopsia is migraine but this is usually experienced in both eyes simultaneously, unlike vitreoretinal photopsia that usually occurs in the temporal field of one eye.
The commonest finding in patients referred with new floaters is a posterior vitreous detachment (PVD). This occurs when the vitreous gel collapses, and the posterior surface of the vitreous separates from the retina. PVD is a normal ageing process and is not in itself harmful. However, it can be a prelude to retinal tears and retinal detachment in a small minority of patients and therefore careful fundus examination is important.
The floaters usually settle with time, but sometimes they persist. Patients can be reassured that the floaters are not harmful (once retinal tears and detachment have been excluded). Floaters can be treated by vitrectomy if patients find them especially intrusive, but this is not necessary for the vast majority of patients.
Always provide (and document) a ‘retinal detachment warning’, advising patients to present immediately if they develop new flashes, increasing floaters or, most importantly, an enlarging peripheral visual field defect.
Please refer patients with a few longstanding vitreous floaters routinely. Alternatively, they could see their regular optometrist, with a request to dilate the pupil and check the peripheral retina.
Please refer patients with an acute onset of floaters or photopsia the same day, or first thing next morning if they present late evening.