There are some nasty infections out there for which the most part can be easily treated with adequate time and diagnosis from your optician. Most are shortlived once antibiotics have been prescribed, but some have the ability to turn quite severe if left undetected or untreated properly.
If you have a herpes simplex eye infection long term damage is possible. It will depend upon what part of your eye is affected by the virus as to what treatment will be recommended.
Drops are normally given if your infection is restricted to the cornea. If your stroma ( middle layer of the cornea) has been infected then anti-viral drops plus drops containing steroids will need to be prescribed. Herpes is a condition that can lie dormant so antiviral tablets over a long term eg. a full year can help stop another break out of the infection