Testing vision on adults

Visual acuity testing is the most important part of the diagnostic workup. Patients need to be "encouraged" to read the smallest possible symbols to achieve the level of best-corrected vision. The pinhole differentiates between decreased vision from refractive errors or pathology and will indicate which further tests are required for a diagnosis. Testing patients with low vision involves the use of special techniques. It is best to use the handheld 20/200 symbol instead of "counting fingers" to assess vision below the 5/200 level. Light perception should be further defined as with or without projection. Finally, no light perception, or NLP, should be determined only by the ophthalmologist. The ophthalmic medical assistant can indicate the possible presence of NLP, but should use the NLP notation only after it has been confirmed by the doctor to exist. Accuracy in determining visual potential is extremely important in screening patients. This assessment must be as careful and thorough as possible. Accuracy in documenting the best acuity level helps to create the correct visual baseline. This visual baseline is then used as the foundation for further diagnostic and therapeutic endeavors.