Decibel scale humphrey visual filed
Very high refractive errors may be corrected by contact lenses to avoid rim artifacts. In order to prevent artifacts, the lens must be properly placed in the trial frame and the correcting lens should be close to the testing eye. One should make sure that the refractive correction and visual acuity entered is appropriate and correlating with foveal sensitivity. As the test results are compared with a normative database of the same age group, one should enter the correct birthdate. For a follow-up printout, the name has to be identical to that entered at baseline. The top of the visual field printout contains key information about the patient including his/her name, age, ID, refraction, and pupil size.
Patient information and examination details For better comparison always do visual field testing by using the same program. Visual field done on two machines of different manufactures cannot be compared. Any abnormal test or unexplained progression has to be repeatable. If the patient is poorly attentive the technician could tailer the Visual Field to be done using a faster strategy like 24-2 SITA fast. The patient needs to understand the task at hand, the nature of the light stimuli, the target to focus on, and that he may pause the test and take a break in case fatigued. It is a good practice for the technicians to undergo self-testing in order to get an idea about the procedure and would help in explaining the procedure better. Pre-requisitesįor a reliable visual field test, a good understanding between the operator (usually an ophthalmic technician) and the patient is important. In this write-up, we will illustrate ten pearls to interpret a Humphrey’s Automated visual field printout. The Humphreys visual field analyzer by Zeiss technology is the most widely used machine for visual field assessment. Automated perimetry is now the current gold standard for both diagnosis and follow-up of glaucoma. It is of great importance to diagnose and monitor optic nerve diseases, notably glaucoma. Advances in the technology of visual field testing have changed our clinical perception of normal and abnormal fields of vision. Further evaluations should provide additional improvements to the clinical performance of the Humphrey Matrix.A visual field encompasses the area of space or area of the external environment that is seen by a steadily fixating eye. Sensitivity for mild glaucomatous visual field deficits can be improved by inclusion of a cluster criterion for locations with reduced sensitivity. Conclusions: Preliminary analysis of the Humphrey Matrix FDT perimeter indicates that it exhibits good sensitivity and specificity for detection of moderate and advanced glaucomatous visual field loss, using the PSD and GHT indices. The use of an analysis procedure incorporating clusters of points with statistically reduced contrast sensitivity for the Humphrey Matrix increased the sensitivity for detecting mild glaucomatous visual field loss to 87%. Sensitivity was 100% for moderate and severe glaucomatous visual field loss, and approximately 76% for mild glaucomatous visual field deficits. Results: Using a criterion of Pattern Standard Deviation (PSD) and Glaucoma Hemifield Test (GHT) visual field indices within normal limits for the Humphrey Matrix, specificity was approximately 86%. Contrast sensitivity for the 24–2 threshold test procedure of the Humphrey Matrix was conducted using a ZEST (Zippy Estimation of Sequential Testing) procedure and a 0.5 cycle per degree sinusoidal grating undergoing 18 Hz counterphase flicker. Glaucomatous visual fields were classified as mild (MD better than –6 dB) moderate (MD between –6 and –12 dB) and severe (MD worse than –12 dB) visual field loss, according to the Humphrey Field Analyzer results. All participants had Humphrey Field Analyzer (SITA Standard) 24–2 test performed prior to Humphrey Matrix evaluations. Methods: 261 subjects (ages 18 to 87 years) with normal visual fields (Humphrey SITA Standard) and normal ocular examinations in both eyes, and 156 patients with glaucomatous visual field loss (Humphrey SITA Standard) were evaluated with the 24–2 threshold stimulus program of the Humphrey Matrix FDT device. Purpose: To determine the clinical performance characteristics of the 24–2 threshold test procedure on the Humphrey Matrix, a device that evaluates contrast sensitivity for frequency doubling technology (FDT) stimuli, in the detection of glaucomatous visual field loss.