A 57-year-old myope presents with sudden onset of floaters and inferior field loss in one eye. What is going on?
Most adults have one or a few floaters that they occasional notice when looking at bright surfaces such as white paper or a bright background such as the sky. They form as part of the natural ageing process when the vitreous shrinks and strings of vitreous material cast shadows on the retina. This is all fine.
However, a sudden onset of floaters is not fine. In this case, the patient has had a posterior vitreous detachment (PVD). This on its own does not cause problems and is known as an uncomplicated PVD. However, the inferior field loss is a very serious sign, which indicates the presence of a superior retinal detachment. Some patients who have a PVD have the complicated type. As the posterior vitreous becomes detached, it tears the retina. Vitreous liquid enters the tear and with the help of gravity, the retina peels of downwards from the tear. Like an orange being peeled from the top. This causes field loss in the inferior visual field. Retinal tears in the superior retina will cause a more rapid detachment than a retinal tear in the inferior retina because of gravity. A retinal tear leading to a liquid propelled retinal detachment is called rhegmatogenous (from the Greek word rhegma, which means a discontinuity or a break). Myopes are more prone to this type of retinal detachment because the eye is bigger than the typical eye and the retina is stretched and under tension. A pull from a detaching vitreous can be enough to cause a tear.
Some people with a rhegmatogenous retinal detachment do not notice visual field loss because the field of the other eye fills in the gap. Anyone presenting with a sudden onset of floaters should be checked for pigment in the anterior one-third of the vitreous (Shaffer’s sign) and undergo visual field analysis and examination of the retina through a dilated pupil. Some eye specialists may need to send the patient to an ophthalmologist for these investigations to be undertaken.