Crohn s disease is usually associated with many system symptoms other than gut problem. In eye it is usually associated with uveitis (inflammation in eye) manifesting as redness,pain,photophobia etc. But when it affects one particular part called Pars Plana,you might not notice any symptoms. Pars Plana is adjacent to peripheral retina, hence inflammation here can spill over inflammatory cells on to peripheral retina and cause these changes. If there is activity treating this inflammation will control complication. Second possibility is, it is not related to your crohn s, could be peripheral retinal degeneration which common especially if you are myopic( -power). Follow up with your ophthalmologist for further management. Regards