RESUMO
Examination of the visual field using static automated perimetry (SAP) is the method of choice for the detection of functional damage secondary to glaucoma. However, with SAP early visual field defects might be missed even if there is already visible damage of the retinal nerve fibre. The microperimetry or beter fundus perimetry provides a detailed examination of the differential luminance threshold within defined retinal areas. However, in contrast to lesions of the retinal receptors, in cases of glaucomatous damage the retinal fibre course has to be considered resulting in a displacement between the structural lesion and the location of the related functional defect. The functional damage may be detected at earlier stages and with enhanced spatial resolution compared to conventional SAP. The extra costs and time associated with the application of fundus perimetry have prevented its widespread use. Current developments are leading to new options.
Assuntos
Glaucoma/complicações , Glaucoma/diagnóstico , Transtornos da Visão/diagnóstico , Transtornos da Visão/etiologia , Testes de Campo Visual/métodos , HumanosRESUMO
Pseudoxanthoma elasticum (PXE) is an inherited disorder that is associated with accumulation of mineralized and fragmented elastic fibers in the skin, vessel walls, and Bruch's membrane. Clinically, patients exhibit characteristic lesions of the skin (soft, ivory-colored papules in a reticular pattern that predominantly affect the neck), the posterior segment of the eye (peau d'orange, angioid streaks, choroidal neovascularizations), and the cardiovascular system (peripheral arterial occlusive disease, coronary occlusion, gastrointestinal bleeding). There is no causal therapy. Recent studies suggest that PXE is inherited almost exclusively as an autosomal recessive trait. Its prevalence has been estimated to be 1:25,000-100,000. The ABCC6 gene on chromosome 16p13.1 is associated with the disease. Mutations within the ABCC6 gene cause reduced or absent transmembraneous transport that leads to accumulation of substrate and calcification of elastic fibers. Although based on clinical features the diagnosis appears readily possible, variability in phenotypic expressions and the low prevalence may be responsible that the disease is underdiagnosed. This review covers current knowledge of PXE and presents therapeutic approaches.