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INTRODUCTION TO FUNCTIONAL TESTS
The eva luation of the patient’s functional status consists of testing the accommodative system and the vergence system. To maintain clear, comfortable, binocular vision for all his visual tasks, a patient needs a number of well functioning visual skills. The patient must be able to align his two eyes and maintain alignment for a sustained period of time. The patient must have sufficient accommodation to focus on the task and to sustain accommodation comfortably. The patient’s accommodation must be accurate and efficient. Accommodation and convergence must interact appropriately. The techniques in this section allow the examiner to screen each of these visual skills and determine if the patient has a functional problem. These procedures allow the examiner to determine if the patient’s functional problem can be corrected with a lens prescription, or if a more comprehensive binocular work- or vision therapy is required.
Each examiner must decide which of these techniques to include in his core examination. The decision is based on the patient’s age, symptoms, the results of the functional entrance tests, and the examiner's professional judgment. Because the functional test sequence is individualized, a flowchart with a main route and side trips is not included in this chapter. (Table 4-1 provides a list of all functional tests and expected findings discussed in the chapter.) This does not, however, imply that efficiency is not an important consideration. Once the examiner has selected the appropriate techniques to include, the following points are considered in determining the flow of the functional testing. Tests done in the phoropter are done at the same time. Tests done out of the phoropter, or in space, are done at the same time. Distance tests are groed together and near tests are groed together. Tests done through the same prescription are groed together.
It is important to realize that the patient’s prescription will influence the status of the accommodative and vergence systems. The examiner must take this into consideration, and decide whether to do the tests through the patient’s old correction (known as habitual findings)，the correction found in the subjective refraction (known as induced findings)，or both．
TABLE4-1 |
