Left sided lateral gaze is affected in lesion of-
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.
Right frontal lobe
Right occipital lobe
Left occipital lobe
Left frontal lobe