Miniature Bull Terriers have short, fine, and glossy coats that are very close to the skin, like Bull Terriers. They are accepted in the ring to be white, white with another colour, or fully coloured. However, like the Bull Terriers, any blue or liver-coloured coats are undesirable. These dogs require minimal grooming. Miniature Bull Terriers are also susceptible to eye problems such as primary lens luxation. PLL is a late onset disease which typically affects dogs between the ages of mid 2 and 7. Younger and older cases are known. During September 2009 a definitive DNA test was released by the Animal Health Trust. This test gives three results: Clear, Carrier, or Affected.