case_images: PMC3646743_01
case_images: Optic disc appearance and visual fields of Patient 1.. (A) Right optic disc cupping (arrow) was noted when the patient first presented with visual loss in the right eye. The left optic disc was normal. Humphrey  visual field perimetry was carried out using the 24-2 SITA-FAST protocol. The right visual field showed a caecocentral scotoma with superior and inferior nasal step defects, in keeping with glaucomatous optic nerve damage prior to LHON disease onset (Mean deviation in September 2008: LE = -2.48 dB, RE = -22.06 dB). (B) Progression of right optic disc cupping with pallor of the remaining neuroretinal rim. The left optic disc remained normal. A dense field defect was present in the right eye (Mean deviation in August 2012: LE = -2.78 dB, RE = -29.25 dB). The changes in peripapillary retinal nerve fibre layer thickness over that period of time have been provided in Figure S1.
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case_images: Figure 1 ). Fluorescein angiography was normal with no evidence of optic disc leakage or vasculitis.
case_images: PMC3646743_02
case_images: Optic disc appearance and visual fields of Patient 2.. (A) Inferotemporal notching of the left optic disc was present at LHON disease onset (arrow). The patient was unable to perform Humphrey  visual field perimetry reliably. Goldmann visual fields showed a steep-sided caecocentral scotoma in the right eye and a central scotoma in the left eye. (B) Advanced bilateral optic disc cupping with pallor of the remaining neuroretinal rim. Although visual field assessment became increasingly difficult as the patient's visual acuities deteriorated to count fingers in both eyes, gradual peripheral field constriction was noted during the course of his follow-up visits. The changes in peripapillary retinal nerve fibre layer thickness over that period of time have been provided in Figure S2.
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case_images: Satisfactory intraocular pressure control proved difficult to achieve and glaucomatous progression in the left eye, with intraocular pressures of 26 mmHg in both eyes, was documented two months prior to LHON disease onset ( Figure 2 ).
case_images: PMC3646743_03
case_images: Optic disc appearance and visual fields of Patient 3.. (A) Advanced cupping of the right disc with a small peripapillary haemorrhage still persisting at the superotemporal disc margin (arrow). The patient had been aware of visual deterioration in the right eye since April 2007. Visual loss started in the left eye in January 2008. (B) Advanced bilateral optic disc cupping with pallor of the remaining neuroretinal rim. The right panel shows the progression of the visual field defects in both eyes at three different time points: (i) after the onset of visual loss in the right eye (Mean deviation in December 2007: LE = -1.05 dB, RE = -25.10 dB); (ii) following disease onset in the fellow eye (Mean deviation in April 2008: LE = -9.03 dB, RE = -22.97 dB); and (iii) at the patient's last follow-up visit (Mean deviation in August 2012: LE = -17.03 dB, RE = -27.40 dB). The changes in peripapillary retinal nerve fibre layer thickness over that period of time have been provided in Figure S3.
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case_images: One year after raised intraocular pressures were first recorded, the patient reported painless visual loss in his right eye over a one-month period down to 3/60 ( Figure 3 ).