यश्चक्षुषि तिष्ठंश्चक्षुषोऽन्तरो यं च-क्षुर्न वेद यस्य चक्षुः शरीरं यश्चक्षुरन्तरोयमयत्येष त आत्मान्तर्याम्यमृतः ॥ १८ ॥
In plain words
The one who lives inside your eye, yet is nothing the eye can claim as its own, whom the eye itself never knows, whose body the eye is, who governs it from within -- that is your self, the ruler seated inside everything, and death does not touch him.
Close to the Sanskrit
He who, dwelling in the eye, is other than the eye, whom the eye does not know, whose body the eye is, who controls the eye from within -- he is your self, the inner controller, immortal.