Could sudden blurred vision be only symptom of tia?

Possible. TIA can present as suddenly decreased vision ("curtain falling" or blurred vision). It can be in one eye or in both eyes (in which case it is usually only on one side of vision). Many other diseases can cause blurry vision - migraines, problems with the eye itself.
TIA blurred visiom. Tia can rarely lead to sudden blurred vision but there are other disease of the eye or the brain that may cause it more often. An ophthalmologist evaluation will be a good starting point.