Symptomatic abnormalities of dark adaptation in patients with age-related Bruch's membrane change.

Symptomatic abnormalities of dark adaptation in patients with EFEMP1 retinal dystrophy (Malattia Leventinese/Doyne honeycomb retinal dystrophy)

“…There is close similarity between the symptoms and functional loss in our patients and those associated with Sorsby fundus dystrophy 67 and age-related changes at the level of Bruch's membrane. 68 In these conditions the deficit has been ascribed to interference of metabolic exchange between the choroid and the retinal pigment epithelium by deposits in Bruch's membrane. This was supported by the observation that the deficit can be reversed by high supplementation of vitamin A, although the effect was not sustained after withdrawal of the supplement.…”

“…The basis of diminished retinal function over areas of confluent deposits are compatible with one or more of the following explanations: decreased outer retinal photopigment content, 66 photoreceptor misalignment, 4,6,49,55 retinal pigment epithelial dysfunction, 56 and delayed metabolic exchange across a thickened Bruch's membrane. [67][68][69] The mutated protein EFEMP1 identified in ML and DHRD, is homologous to fibulins, which are extracellular matrix glycoproteins that bind to elastic fibers 70 and through attachments to nidogen, interact with collagen IV and laminin in basement membranes. 71 If this mutation alters supramolecular assembly of basement membrane components within Bruch's membrane, this could contribute to the development of drusen in ML/DHRD.…”

The effect of bleach duration and age on the ERG photostress test

“…Histological work by Sarks [15] identified changes to Bruch's membrane and the presence of basal linear deposits within the retina in eyes with a normal fundus appearance and often good visual acuity. Changes in the permeability of Bruch's membrane have been suggested to be the cause of delayed dark adaptation in ARM [16], so individuals with pre-clinical ARM might be expected to show abnormal time constants. Confounders such as media opacities could also be influencing the spread of data.…”

Functional loss in early age-related maculopathy: the ischaemia postreceptoral hypothesis

“…Most studies have explained their functional findings as being due to an alteration at the photoreceptor level (abnormal orientation or shape or photoreceptor loss) and/or by the kinetic model. 21,25,34,41,44,45 In contrast to a structural abnormality or loss of photoreceptors that might result in decreased photopigment and photosensitivity, the kinetic model suggests slowed regeneration of photopigment owing to slowed transfer of vitamin A to the retinoid cycle through a thickened Bruch's membrane. The kinetic model proposes that cones and rods have abnormal adaptation and therefore altered recovery dynamics caused by the dysfunction in the photopigment regenerative capacity.…”

“…32,33 The functional results of these tests cannot be given in detail but all show an impairment of cone-or rod-mediated function (or both) in early ARM. In addition, there is preferential vulnerability of the S-cone 34,35 and rod pathway [36][37][38][39][40][41][42] in early ARM over the L-and M-cone pathway. Curcio 43 has demonstrated that parafoveal rods were the first to die in early ARM and the last surviving photoreceptor in late ARM was a cone.…”