Summary of Letter:

 باسمه تعالى
Respected Mufti Saheb
السلام عليكم و رحمة الله و بركاته
 I cannot protect my eyes (from sin). Please advise me on how to overcome this malady.

Summary of Reply:

باسمه تعالى
Respected Brother/Sister
السلام عليكم و رحمة الله و بركاته

Allah Ta’ala has created natural means for the protection of the eyes from all sin. With every eye Allah Ta’ala has created two shutters — one at the top and another at the bottom. When one’s sight falls in the wrong place, immediately close both these shutters.
There is also another means of uprooting this disease (of gazing at ghair mahrams — women with whom marriage is permissible). Sit in solitude, close your eyes and recite the following verse: “Does he not know that verily Allah is watching” (the Arabic should be recited — Surah 96 Verse 14). While reciting this verse ponder over the following: “If I am in the presence of my father, Ustaad or spiritual mentor and a strange woman (ghair mahram) had to pass, would I look at her ? Most definitely not. How can I then look at any woman in the presence of Allah Who is watching at all times.”
Practice this for ten minutes every day. Over and above that whenever you get the opportunity ponder over this until it becomes firmly embedded in the heart.
May Allah Ta’ala help you.
(Maktoobat Faqihul Ummah V.1 pg. 42)