Abstract
Purpose::
To validate face fields, a simple clinical technique for determining how a patient fixates, by comparing face field results to SLO and MP-1 findings
Methods::
The charts of all patients who underwent SLO or MP-1 evaluation between February 2005 and September 2006 were reviewed. Patients with scotomas in the central visual field from macular disease were identified. All patients who underwent face fields prior to but at the same visit as SLO/MP-1 evaluation were included. The location of the scotoma relative to fixation on face fields was compared with the positioning of the fixation cross on SLO/MP-1 evaluation.To perform face fields, the patient occludes one eye. The examiner instructs the patient as follows: "Look at my nose so you can see it as clearly as possible. While you are looking at my nose, are there parts of my face that are missing, or blurry, or distorted?" The response are recorded, for example, as ‘the eyes are blurry’, or ‘the eye to his right is blurry’, or ‘the face to his left is blurry.’
Results::
Two hundred seventy eyes of 154 patients were included. Face fields provided the same fixation information as the SLO/MP-1 in 136 eyes (50%). Face fields differed slightly from SLO/MP-1 in 66 eyes (24%); for example, face fields might show the scotoma up and to the right, while SLO/MP-1 showed the scotoma above. In 65 eyes (24%), the face field findings differed from the SLO/MP-1 findings. A scotoma was not detected by face fields in only 25 eyes (9%).
Conclusions::
Face fields provided insight into the location of the preferred retinal locus for fixation in 74% of patients. It is a simple test which can be used in the clinic or at the patient's home by clinicians as well as by low vision therapists and OTs. Face fields can help in coaching a patient to reinforce the PRL, to view the object of interest optimally and to use low vision devices more effectively. Face fields also have a much lower false negative rate than the Amsler grid.
Keywords: low vision • age-related macular degeneration