yoga with grace

स्वविषयासंप्रयोगे चित्तस्वरूपानुकार इवेन्द्रियाणां प्रत्याहारः 

svavisayasamprayoge cittasvarupanukara ivendriyanam pratyaharah

Pratyahara is disconnecting from sense objects and purifying the mind

Yoga Sutras of Patanjali, 2.54

sva = its own
visaya = objects
samprayoge = upon disconnecting
citta = of the mind
svarupa = its own nature
anukara = imitate
iva = as if
indriyanam = of the senses
pratyahara = sense withdrawal

One way to look at this could be to see it as like cleaning the glasses of your mind.