Leber's hereditary optic neuropathy mitochondrial DNA mutations in normal-tension glaucoma.

BACKGROUND: in Leber's hereditary optic neuropathy, increased optic nerve cupping has been reported by several authors. Recently, a mitochondrial DNA (mtDNA) mutation at nucleotide 11778 typically associated with Leber's hereditary optic neuropathy (LHON) was identified in a patient treated for glaucoma but lacking typical signs of LHON. The question arises: should all normal-tension glaucoma patients be further evaluated for LHON? METHODS: we screened 54 unselected patients with normal-tension glaucoma (age range 20-96 years, 16 men and 38 women) for the primary mtDNA LHON mutations at nucleotides 3460, 11778 and 14484. RESULTS: none of the patients harboured the mtDNA mutations at nucleotides 3460, 11778 or 14484 (95% confidence intervals for each mutation ranged from 0% to 5.3%). CONCLUSIONS: primary LHON mtDNA mutations are rare or absent in unselected normal-tension glaucoma patients. Therefore, unselected normal-tension glaucoma patients should not be screened for these mutations. It is probable that only normal-tension glaucoma patients with atypical features (rapid progression, early deep central scotoma, pallor of neuroretinal rim, elevated disc, peripapillary teleangiectasia) or a positive family history of visual loss compatible with a matrilinear transmission should be further evaluated.

Decreased Heidelberg Retina Flowmeter (HRF) parameter "flow" at the papilla shortly after smoking a cigarette.

PURPOSE: To investigate the effect of smoking a cigarette on the Heidelberg Retina Flowmeter (HRF) parameter "Flow" at the papilla of healthy young volunteers. METHODS: Three HRF measurements were taken over the papilla (20 x 5, 256 x 64 pixels) in fourteen occasional smokers and in 14 non-smokers. Ten minutes later three similar HRF measurements were again made. In between the two series of measurements occasional smokers were asked to smoke a cigarette (Marlboro, nicotine content 9 mg) and non-smokers not. RESULTS: In occasional smokers, the values (arbitrary units) of the HRF parameter "Flow", calculated at the papilla (50 x 50 pixels), significantly (P = 0.01) decreased (11.2 +/- 3.5%) after smoking a cigarette. In contrast, in non-smokers, the values of the HRF parameter "Flow" did not decrease significantly (2.9 +/- 2.2%) when measurements were repeated 10 minutes later. CONCLUSIONS: The results of the present study suggest that smoking a cigarette can affect the HRF-parameter "Flow" at the papilla. The clinical implication of such an observation needs further investigations.