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Functional correlates of abnormally increased annular fundus autofluorescence in different retinal dystrophies
Author(s) -
ROBSON AG,
MICHAELIDES M,
SAIHAN Z,
BIRD AC,
FITZKE F,
HOLDER GE,
MOORE AT,
WEBSTER AR
Publication year - 2008
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2008.4251.x
Subject(s) - ophthalmology , medicine , retinitis pigmentosa , fundus (uterus) , dystrophy , visual acuity , photopic vision , erg , electroretinography , atrophy , retinal , pathology
Purpose To examine the functional significance and stability of annular fundus autofluorescence (AF) abnormalities in patients with different retinal dystrophies. Methods One hundred patients were ascertained who had a parafoveal ring of high density AF. Seventy five had a clinical diagnosis of retinitis pigmentosa (RP) or Usher syndrome with good visual acuity; 20 of 75 had serial AF imaging. Twenty five others included cases of cone or cone‐rod dystrophy (GUCA1A, RPGR, RIMS1) and “cone dystrophy with supernormal rod ERG” (KCNV2). International‐standard full‐field and pattern ERG (PERG) testing was performed. Some patients underwent fine matrix mapping (FMM). Results Results: a) The AF ring radius correlated positively with PERG P50 in non‐syndromic RP (R=0.79, p<0.0005, N=50) and in Usher syndrome (r=0.77, p<0.0005, N=25). The ring encircled areas of preserved photopic function. Serial AF revealed progressive ring constriction in 10 of 20 cases. b) In the 25 patients with cone or cone‐rod dystrophy, AF rings resembled those seen in RP or encircled areas of central atrophy. There was an inverse relationship between P50 and ring size in those with detectable PERGs. High density arcs corresponded with gradients of sensitivity change. There was evidence of AF ring expansion in some cases. Conclusion Conclusions: Parafoveal rings of high density autofluorescence are non‐specific manifestations of retinal dysfunction associated with gradients of sensitivity change. High density rings progressively constrict in a high proportion of patients with RP and good visual acuity. Progressive ring expansion may occur in different forms of cone and cone‐rod dystrophy.