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What is True about visual testing in a child –a) Visual evoked potentialb) Teller's acuity card testc) Perimetryd) Keratometry and explain in detail?
The ordinary tests types cannot be used with young children who are easily distracted and may not know alphabets. So maturation of infant visual function has been studied by two techniques:-

Pattern visual evoked response/potential (VEP)

Preferential looking behaviour eg. Teller or Cardiff acuity card


Other tests include:-


Keeler - Elliot test  
Kay picture test     
Fooks symbols       
`E' test       
Landolt 'C' chart  
Sheridon - Gardiner
HOTV 
Optokinetic nystagmus
Photostress test
STYCAR (sight testing for young children and retarded)