Chazal (Yuma 29a) say that fantasizing about immoral pleasures is, in some ways, worse than the immoral acts themselves. The body of a Yid is like a Beis HaMikdash, and his heart (i.e. mind) corresponds to the Kodesh HaKodoshim. Dare he defile it by playing around with impure thoughts and sensations? Titus harasha demolished the Temple that stood on earth. But forbidden thoughts in a Yid do far more harm. They profane the Kodesh HaKodoshim of the Beis HaMikdash that stands on High (see Nefesh HaChaim, part 1 ch. 4).
On a positive note. One who in his lifetime wholeheartedly trusted in Hashem will be able to likewise place his trust in Hashem after he dies. That trust has the power to break through and reach all the way up to the Kisei Hakavod. His abiding unshakeable trustin Hashem won’t fail him, even in the depths of gehinnom. The trust that he held fast to acted to purify his soul. And in his judgement it will come to his defence. This is alluded to in the passuk (Tehillim 130:7) יחל ישראל אל ה' וגו‘ - Yidden! Put your trust in Hashem, for with Hashem is kindness. The more we bind ourselves to Hashem the more kindness is revealed, even where the recipient is unworthy. (Otzros Ramchal vol. 4, pg. 246)
Here are some ideas on how to repair damage done to the eyes, to be used in conjunction with sincere teshuva.
Simple eye contact transfers levels of kedusha and helps to wipe the old blots off one’s slate. Our holy sages come forward with some user-friendly suggestions of ways to tap into spiritual powers via our vision. For starters, when you are given an aliyah in shul, says the Reishis Chochma (Sha’ar HaKedusha ch. 8), be sure to follow along in the Sefer Torah. The Magen Avraham (siman 114) quotes the Arizal, that a great spiritual light comes upon you by simply peering up at the parchment during hagbah until you recognize the letters. They exude a powerful radiance which will also help to erase old spiritual scars.
Gaze intently at the face of a tzaddik. Then your soul will make contact with the light that is burning in his soul. This suggestion is especially effective on Shabbos and Yom Tov.
When you go to shul, you are bringing your eyes to a kedusha power station! By looking at a shul or a Beis HaMidrash - even from the outside, your soul is elevated. Once you step inside, the effect is heightened, and even more so upon approaching the Aron HaKodesh. Looking at the name of Hashem spelled yud-kay- vav-kay connects your eyes with piercing, penetrating rays of kedusha.
The Ben Yehoyada (Shabbos 118) proposes looking carefully at the two letter shins on the tefillin shel rosh before donning it. You will thereby draw out and imbibe a special light from within them. This will also help you not to be mesiach daas whilst wearing them. You could gaze at your tzitzis, says the Peleh Yo’etz (Ri’ah), and keep looking in the sefer when you learn and in the siddur as you daven.
Rabbeinu Yonah writes in Shaarei Teshuva that shedding tears of remorse over our aveiros is a tikkun for sins committed by the eyes. The Orchos Tzaddikim (shaar teshuva) adds that when a person cries over his aveiros, he should say: ״May my tears extinguish Your anger, and may my improved behavior turn Your wrath away from me. ״ Likewise, says the Peleh Yo’etz, crying upon hearing of the death of a tzaddik, or from longing for Mashiach, washes our eyes out wonderfully.
(See the sefer Kedushas Hachaim for further ideas).