Table 1.

Summary of Retinal Functional and Structural Testing

Subject	Age	Age at Onset	BCVA	GVF	Foveal Threshold	Color	OCT Foveal Thickness	Rod ERG b-Wave Amplitude*	Rod ERG b-Wave Timing† (msec)	Cone ERG Flicker Amplitude‡	Cone Flicker Timing§ (msec)	mfERG	Cone Spacing Mean Z-Score	T8993C Mutant Heteroplasmy in Blood||	T8993C Mutant Heteroplasmy in Hair Follicles||
I-1	48	34	20/50	Dense paracentral scotoma	27 dB	6 crossing errors, tritan axis of confusion	74 μm	57	103.5	42	36.5	Severe reduction centrally	6.37	78	87
II-1	28	12	5/125	Large dense central scotoma	Not done (unstable fixation)	Not able	Not done (unstable fixation)	29	102.5	25	35.9	Not done (unstable fixation)	Not done	78	99
II-2	26	None	20/16	Full	38 dB	No errors	141 μm	70	86.5	83	28.6	Normal	−0.09	42	54
II-3	22	18	20/25	Slight constriction, 14e target	35 dB	1 crossing error, tritan axis	82 μm	22	99.5	22	33.7	Moderate reduction centrally	6.92	95	99
II-4	16	10	20/50	Constriction to 20° centrally	32 dB	2 crossing errors, tritan axis	99 μm	39	102.5	46	35.1	Severe reduction centrally	6.36	92	99

^*Expressed as a percentage of the normal mean amplitude (272 μV). 2 SD below normal is 65% for rod b-wave.

^‡Expressed as a percentage of the normal mean amplitude (121 μV). 2 SD below normal is 54% for cone flicker.

^†Normal rod timing is <105 msec.

^§Normal cone flicker timing is <32 msec.

^||The degree of T8993C mutant heteroplasmy is expressed as percent of total mitochondrial DNA.