Left sided lateral gaze is affected in lesion of-
Right frontal lobe
Right occipital lobe
Left occipital lobe
Left frontal lobe
Voluntary horizontal gaze in one direction begins with the contralateral frontal eye field.
If horizontal gaze is affected, the damage may be:-

Cortical center: - Contralateral frontal eye field.
Brainstem center: - Pons (Pontine paramedian reticular) formation.
Cranial nerve nucleus: - Abducens (6th nerve) nucleus.