The windshield taped up except for a round hole in the middle and the windows blacked out – who would voluntarily drive a car like that? Some do, without even knowing it. Because not everyone who has passed the official eye test sees well. The test measures only a tiny central point of visual acuity. An essential component of vision, however, is also peripheral vision, i.e. what is perceived around the focus from the corners of the eyes. This so-called visual field can be limited by a wide variety of pathological causes, from glaucoma to stroke, without the patient being aware of his or her disease.
Risk of accidents due to restricted vision
For a child who runs across the road from the side, such reduced vision becomes a danger to life: If the motorist does not perceive the child until he or she has him or her in focus, it may already be too late to brake. “Regular ophthalmological checkups prevent such horror scenarios,” says Prof. Dieter Friedburg, head of the “Ophthalmological Optics” department in the German Professional Association of Ophthalmologists (BVA). “This is because we always examine the peripheral vision of our patients during the examination for roadworthiness. In doing so, we can diagnose the causes of a restricted visual field, initiate appropriate therapy and thus avert severe disease progression.”
Tumor or stroke – readable in the eye
The loss of parts of the visual field can be caused by various diseases. In many cases, the patient does not notice at all that parts of his visual field are restricted, since the central visual acuity is not affected. This makes targeted control all the more important, because visual field deficits can also indicate other diseases. In the ophthalmological practice it happens again and again that the specialist diagnoses a stroke due to a limited peripheral vision. The symptoms of the stroke, such as paralysis, may recede, but the danger has often not been averted because of this. Based on visual field loss in typical form, the ophthalmologist may determine that the problem has not yet resolved and refer the patient to the neurologist or primary care physician for treatment.
Pituitary tumors, usually benign growths in the brain area, are also frequently discovered by the ophthalmologist; they bring with them a very characteristic restriction of peripheral vision. Affected persons then see as if with blinkers – for drivers this can lead to disaster. If such a tumor remains undetected, it can lead to blindness in the worst case. Depending on the form of the visual field loss, the ophthalmologist may even be able to identify where in the brain a disorder is present.
Saving from blindness with regular eye checks
It’s especially bad when peripheral vision is limited due to glaucoma. Also known as glaucoma, this disease of the optic nerve affects about 800,000 people in Germany. Prof. Friedburg therefore urges early detection: “If glaucoma is detected too late, it may have already destroyed too many cells of the optic nerve and the retina. The restriction of the visual field cannot be reversed in glaucoma – so the patient’s vision cannot be restored.” Regular preventive examinations with an optic nerve check and examination of intraocular pressure by an ophthalmologist prevent glaucoma from occurring in the first place.
A rarer cause of such visual field losses are so-called degenerative diseases of the retina, such as retinitis pigmentosa. Dr. Uwe Kraffel, 1. chairman of the BVA, to the meaning of the regular investigation: To the evaluation of the eyesight absolutely also the investigation of the visual field belongs to it, a simple eye test with the optician is not sufficient there. Because the comprehensive diagnostics of the ophthalmologist is aimed not only at the good vision of the patient, but also on possible general and serious eye diseases.” Source: Professional association of the eye physicians of Germany registered association. (BVA)
