The peripheral visual field is largely unexplored to our current method of clinical testing, static threshold automated perimetry. Until the advent of computerized perimetry (quantitation of the visual field) 35 years ago, clinical practice was to test the full visual field manually by kinetic (moving target) Goldmann perimetry. With the evolution to computerized static perimetry, the focus shifted to the central 30. This seldom tested area, outside the central visual field, represents over 3 times the territory currently evaluated. This is important because the peripheral field is critical for navigation of the environment (functional vision), can be the earlest site of visual field defects, may be the most appropriate territory to follow patients needing changes in intervention and gives a more detailed and full evaluation of vision. Our pilot data shows that advances in knowledge from our past Merit Reviews coupled with new methodology will now allow us to develop testing of the full visual field using static stimuli in a time-efficint precise and accurate way. This will give a comprehensive assessment of the visual field. Main Hypothesis: Using larger perimetric stimuli in the peripheral visual field along with a Bayesian testing strategy will allow an efficient, accurate and precise perimetry method so that testing of the full visual field is practical and produces an improved assessment of vision.
Specific Aim 1. Characterize the location of far peripheral visual field defects of optic neuropathies to static stimuli. We will test the full visual field in 120 stable glaucoma and idiopathic intracranial hypertension subjects with a broad range of optic nerve damage to determine where defects occur in the far peripheral visual field to static automated testing.
Specific Aim 2. Develop a Bayesian strategy to test the full visual field in less than 10 minutes per eye. We will develop a pattern of test locations in the central and peripheral field based on where visual field defects most often occur. By only using stimulus sizes and intensities that give excellent repeatability, a Bayesian test strategy, and results from frequency of seeing curves, we will develop a new perimetry test.
Specific Aim 3. Validate the full visual field testing using the new Bayesian strategy perimetry test. Sixty healthy observers will be tested twice and normative limits for the new test calculated. The 120 optic neuropathy subjects will be retested and the results compared.
Specific Aim 4. Correlation of structure of the retinal nerve fiber layer and function (perimetry) using Optical Coherence Tomography (OCT) with the full visual field will provide stronger correlations than only the central visual field. We expect to find visual field defects i the peripheral visual field in cases where central visual field testing is normal and develop a tes that will give a better assessment of visual function. This will allow more accurate results leadin to earlier detection of diseases like glaucoma, earlier disease intervention and better structure / function correlations. Improved test precision will lead to lower retest variability and earlier detection of visual field change. Also, with cases of moderate to severe visual loss, evaluation of the full visual field will provide a larger area to monitor for changes in vision. Lastly, using lager stimuli will lead to almost a doubling of the effective dynamic range of the test that will lead to better assessment of veterans with poor vision. These test attributes should allow improved functional visual assessment for veterans with glaucoma and other optic neuropathies and improved outcome measures for VA rehabilitation research protocols.
Testing the full visual field in a more accurate, precise and efficient way will lead to 1) earlier diagnosis and 2) earlier detection of visual field change allowing more timely intervention; 3) a more comprehensive evaluation of functional vision and 4) better correlation of change in optic nerve structural damage with visual field performance. In addition, with cases of moderate to severe visual loss, evaluation of the full visual field with an almost a doubling of the useful dynamic range will provide a larger area to monitor for changes in vision. This will make possible an improved and more comprehensive assessment of functional vision for veterans with glaucoma and other optic nerve diseases and improved outcome measures for VA rehabilitation research protocols.
