Yōga Sūtra 3.21

कायरूपसंयमात्तद्ग्राह्यशक्तिस्तम्भे चक्षुःप्रकाशासम्प्रयोगेऽन्तर्धानम्।

By samyama of physical body form, suspending eye's ability to grasp, obstructing the contact of light with eyes, disappearance (of object) is achieved.