The Mishna Zevachim (112b) says that in Mishchan Shiloh the maaser sheni and kadshim kalim could be eaten in any place that was within eyesight of the Mishkan. In the Mikdash it was eaten within the walls of Jerusalem. The Gemarah (118b) says רבי אבהו אמר אמר קרא בן פרת יוסף בן פרת עלי עין עין שלא רצתה לזון וליהנות מדבר שאינו שלו תזכה ותאכל כמלא עיניה. What is the connection between Yosef not taking the wife of Potifar and koshim kalim eaten within eyesight? The Gemarah says that the descendants of Yosef are not affected by yetzer harah בן פורת עולי עין, why are they above ayin harah?
Yosef says ועתה אל תעצבו ואל יחר בעיניכם כי מכרתם אתי הנה כי למחיה שלחני אלקים לפניכם. Yosef's perspective of life is to see the good in things. Even the heinous act of being sold into slavery is seen by Yosef as just a means of setting up Klal Yisrael in Egypt. Even more than this, when he repeats this to the brothers after Yaakov's passing, he says וְאַתֶּ֕ם חֲשַׁבְתֶּ֥ם עָלַ֖י רָעָ֑ה אלקים חֲשָׁבָ֣הּ לְטֹבָ֔ה לְמַ֗עַן עֲשֹׂ֛ה כַּיּ֥וֹם הַזֶּ֖ה לְהַחֲיֹ֥ת עַם־רָֽב׃ וְעַתָּה֙ אַל־תִּירָ֔אוּ אָנֹכִ֛י אֲכַלְכֵּ֥ל אֶתְכֶ֖ם וְאֶֽת־טַפְּכֶ֑ם, not only does he tell them not to worry, but he would take care of them because his descent to Egypt turned positive. This is despite the fact that the brothers did not have any intension of doing anything for the success of Yosef, nonetheless the fact that it turned positive was reason to be positive toward his brother as well (see Tanya end of Ch. 12, Likutay Sichos volume 5 Vayigash sicha 2 footnote 48.) It is the ability of Yosef to see the good even in what appears to be bad that made him the perfect man to be able to reverse the bad fortunes of the famine.
It is this eye of goodness that Yosef has which allows him to see kedusha even beyond the walls of kedusha. The positive eye of Yosef allows him to perceive kedusha even into areas which are beyond the walls of kedusha. Therefore, his Mishkan allows maaser and kodshim kalim to be eaten in anything within eyesight. Even that which is beyond the boundary can be elevated (Rav Kook in hesped on Hertzel and Shmuot Reyah.) This is what allows Yosef to not be affected by ayin harah. Those affected by ayin harah it means they are affected by external surroundings and events. Someone who needs external validation and acceptance is affected by how others view him. Someone who is able to rise above external negative events is not bothered by the view of others and therefore the evil eye is counterbalanced by his good eye (see Ein Ayah Berachot 55b translated on marehkohen.com)