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C.F. Chicani, P. Quiros, P.Y. Sacai, L. Mendieta, C. Tamaki, A. Berezovsky, S.R. Salomao, V. Carelli, A.A. Sadun, R. Belfort; Visual Field Analysis of Leber's Hereditary Optic Neuropathy (LHON) Asymptomatic Nonaffected Carriers . Invest. Ophthalmol. Vis. Sci. 2006;47(13):755.
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© ARVO (1962-2015); The Authors (2016-present)
To describe visual field findings in asymptomatic carriers of Leber's Optic Hereditary Neuropathy (LHON)
138 eyes of 69 maternally related nonaffected carriers from a large LHON Brazilian pedigree with homoplasmic 11778/ND4 haplogroup J mutant mitochondrial DNA, were submitted to visual field examination by 24–2 Humphrey visual field testing. Inclusion criteria were being older than 10, no visual complaints, normal ophthalmologic exam, and best corrected visual acuity ≥ 20/25. Reliability parameters were classified as good if fixation losses (FL), false positives (FP) and false negatives (FN) were all normal according to the Humphrey’s normative parameters; fair if FL between 10 and 15%, and or FP and or FN between 10 and 20%, poor if FL between 15 and 20%, and or FP and or FN between 20 and 30%, and finally unreliable if FL greater than 20% and or FP and or FN greater than 30%. Exclusion criteria were unreliable parameters and or fovea threshold smaller than 35 dB. The pattern deviation map was considered abnormal if present were one or more points with less than 0.5% probability, 3 or more points less than 1.0%, five or more points less than 2% and seven or more less than 5% probability of being normal. Other ways was considered normal.
The abnormal exams were categorized, according to the defect presented as localized (L) or diffuse (D). L defects were sub classified as glaucomatous (LG) (arcuate defect or nasal step) or non glaucomatous (LNG) (central or paracentral defect). For normal and abnormal groups and subgroups were analyzed mean deviation (MD) and pattern standard deviation (PSD).
21 (16%) of 138 met the exclusion criteria and were excluded from the analysis,62 (53%) of the remaining eyes demonstrated normal visual fields, 55 (47%) were abnormal, 29 of them D and 26 L; 15 LNG and 11 LG.
For the normal group MD was –2.23 (–0.5 to – 3.77) and PSD was 1.54 (1.00 to 2.10). For the abnormal group MD was –3.95 (–1.53 to –8.51), – 4.34 for the D, –3.17 for LNG and –3.91 for LG; and PSD was 3.14 (1.18 to 7.75), 3.59 for D, 2.34 for LNG and 3.08 for LG.
Almost half of the nonaffected LHON carriers presented with different types of visual field defects despite a lack of symptoms or decrease in visual acuity. We will compare these with other functional and anatomic assessments and follow these patients over to determine whether such visual field abnormalities are harbingers of conversion to affected status.
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