Recently the contract for DVLA assessments was tendered out to one of the large multiple chains. However, we are still able to perform the same tests check visual fitness to drive on a private basis. This involves measuring your level of vision in each eye separately, with and without spectacles, and assessing your peripheral vision. The latter is carried out with both of your eyes open, using a Henson Pro Visual Field Analyser and is called an Estermann visual field test.
You can arrange for an appointment privately if you have failed the test in the past and wish to try again before contacting the DVLA for reassessment.