Please tell an old summoner how to deal with stealth 2015

Lately ive started doing normals again to learn top role so i got more options for season rewards ranked eventually, since thats the most interesting role to me right now since i normally mained adc and support and that forced me to work together with people who more often than not could not be relied upon, wich handicaps me too much in my options. So solo lane is more fun imo, but i hate playing apcarrys so yeah top it is.

To the subject; I had a game against a rengar as ap teemo and though early i could deal with him fine staying away from the brush and popping him on the head everytime he last hit a minion from it i had severe difficulties surviving ANYTHING the moment he hit 6 and could stealth.

Same with shaco in another game who was jungler, i won my lane in that game and i think we won that game aswell as yorick but this shaco kept destroying me every single time i was caught out anywhere alone on the map.

I do not know how vision works anymore in this season, theres so many new items, take to mind i havent played SR in 1.5 years or so and even back then i hardly ever did since i had a whole year of only arams and dominion..

The worst is when i think about how it makes no sense that a cc-less (well ok ult lol but cmon) champ like eve has practically no stealth anymore save for her ofscreen roam.. but a hard cc 100-0 champ like rengar or hard cc 100-30/0 champ like shaco can just crawl around you undetected. :s

0 counter play like that, all i could do was stick to my adc to stay safe(r) i couldnt push at all anymore so that wrecks my purpose.

Tips?