Evolution of reticular pseudodrusen.

AIMS: To report observations relating to the clinical recognition and possible basis of reticular pseudodrusen (RPD). METHODS: This retrospective study reports the evolution of RPD in 166 patients who had follow-up of over 1 year using multiple imaging techniques. Mean age when first seen was 73.3 years and the mean period of observation was 4.9 years (range 1-18 years). Associated macular changes were recorded. RESULTS: RPD were first identified in the upper fundus as a reticular network, which then became less obvious, developing a diffuse yellowish appearance. RPD also faded around choroidal neovascularisation (CNV). RPD therefore could be transient but the pattern often remained visible outside the macula or nasal to the discs. Manifestations of age-related macular degeneration (AMD) were present in nearly all eyes and there was a particularly high association with CNV (52.1%). In one clinicopathological case abnormal material was found in the subretinal space. CONCLUSIONS: The prevalence of RPD may be underestimated because their recognition depends upon the imaging method used, the area of fundus examined and the confusion with typical drusen. The pathology of one eye suggests that RPD may correspond to material in the subretinal space.

Retinal basement membrane abnormalities and the retinopathy of Alport syndrome.

PURPOSE: To determine the effects of X-linked and autosomal recessive Alport syndrome on retinal basement membranes and how these result in the characteristic perimacular dot-and-fleck retinopathy, lozenge, and macular hole. METHODS: The type IV collagen chains present in the normal retina were determined immunohistochemically. Ten patients with Alport syndrome underwent retinal photography and optical coherence tomography to determine the thickness of the internal limiting membrane (ILM) by segmentation analysis, the layers affected by the retinopathy, and any correlates of the lozenge and macular hole. Bruch's membrane was examined directly by electron microscopy in a donated Alport eye. RESULTS: The alpha3alpha4alpha5 type IV collagen network was present in the normal ILM and in the retinal pigment epithelium basement membrane of Bruch's membrane. In Alport syndrome, the ILM/nerve fiber layer and Bruch's membrane were both thinned. The dot-and-fleck retinopathy corresponded to hyperreflectivity of the ILM/nerve fiber layer in the distribution of the nerve fiber layer. The lozenge and macular hole corresponded to temporal macular thinning. The thinning across the whole retina was principally due to thinning of the ILM/nerve fiber layer and inner nuclear layer. CONCLUSIONS: The Alport dot-and-fleck retinopathy results primarily from abnormalities in the ILM/nerve fiber layer rather than in Bruch's membrane. Thinning of the ILM/nerve fiber layer contributes to the retinopathy, lozenge, and macular hole, possibly through interfering with nutrition of the overlying retina or clearance of metabolic by-products.

Relationship of Basal laminar deposit and membranous debris to the clinical presentation of early age-related macular degeneration.

PURPOSE: To correlate basal laminar deposit (BLamD) and membranous debris, including basal linear deposit (BLinD), with the evolution of early age-related macular degeneration (AMD). METHODS: A clinicopathologic collection of 132 eyes with a continuous layer of BLamD was reviewed. The thickness and type of BLamD and the sites of membranous debris deposition were correlated with the clinical progression of the disease. RESULTS: Two types of BLamD, termed early and late, were identified based on light microscopic appearance by using the picro-Mallory stain. The progressive accumulation of late type BLamD correlated well with increasing BLamD thickness, advancing RPE degeneration, poorer vision, increasing age, and clinically evident pigment changes. Membranous debris initially accumulated diffusely as BLinD, most eyes with BLinD and early BLamD remaining funduscopically normal. However, membranous debris also formed focal collections as basal mounds internal to the RPE basement membrane and as soft drusen external to the basement membrane. Eyes in which membranous debris remained confined to basal mounds belonged to older patients with poorer vision, whereas patients with soft drusen were younger and had better vision. CONCLUSIONS: The presence of BLinD and early BLamD define threshold AMD, which manifests clinically as a normal fundus. Although late BLamD correlates most closely with clinical pigment abnormalities, it is the quantity and sites of membranous debris accumulation that appear to determine whether the disease develops pigment changes only or follows the alternative pathway of soft drusen formation with its attendant greater risk of choroidal neovascularization (CNV).