The symptoms of macular disease include blurring and distortion of vision with micropsia or macropsia, which can be assessed with an Amsler grid. (This consists of a piece of paper showing a 10cm square divided into 5mm squares with a central fixation dot). The subject is asked to fixate on the central dot, with each eye separately, at one third of a metre and to mark on the chart with a pencil, scotomata or areas of distortion. When abnormalities are present, immediate referral to an ophthalmologist should be done. The commonest conditions affecting the macula are disciform macular degeneration and central serous retinopathy.
This condition typically affects the elderly but inherited forms may affect younger people. Ophthalmoscopy may show small grey, yellow or white lesions, like small crystals, at the macula. These are called 'Drusen' (German, druse = nodule). The visual acuity is usually well preserved, 6/9 or 6/12, until a further complication occurs, the development of a subretinal neovascular membrane that spreads under the macula and reduces vision to 6/60 or less. To prevent the visual acuity from deteriorating below standard, regular followup is essential. In the early stages when the vision is distorted, but the acuity well preserved, the subretinal membrane can be obliterated by argon laser treatment.
The condition can affect healthy young adults. Only one eye is usually affected and reduction of acuity is mild (6/12 or 6/18). Direct ophthalmoscopy shows dulling of the macular reflex, representing a shallow central retinal detachment. Vision recovers spontaneously within six weeks in 90% of cases. Stereoacuity is temporarily lost and pilots should not fly until full recovery occurs. Laser treatment has been shown to speed the resolution of symptoms, but does not improve the final visual performance. No treatment is usually advised. The condition recurs in 20 to 30% of cases and the second eye is affected in 20%.
An applicant with a history of central serous retinopathy may be assessed as having a condition that is not of aeromedical significance only if:
