Issues for Comment: 1.) Changes in electronic and optical technology over the past decades have led to many significant advances in ophthalmic devices and
testing procedures. Laser scanning devices have become common-place. Specifically, Optical Coherence Tomography (OCT) is routinely used to measure central macular thickness (CMT,) image retinal microstructure and to analyze optic nerve cupping and retinal Nerve Fiber Layer (NFL) thickness. Digital fundus color photography and Fundus Auto Fluorescence (FAF) photography have improved because of better filters and more sensitive recording media. FAF is non-invasive and has become more widely used to detect and document retinal pathology than it used to be.
Visual acuity testing has changed from the use of standard projection charts to electronically displayed characters that vary in shape and contrast as well
as size. Using new display devices, traditional Snellen acuity measurement are still performed, but other less standardizied methods are in use as for special purposes. The ability to vary character types, spacing, brightness, color and contrast has made it possible to reduce familiarity with testing procedures. The variability can be used to help detect malingering or to facilitate acuity measurements of individuals who are pre-literate or illiterate. Low contrast charaters or sine-wave gratings are in fairly wide acuity testing use. They are not readily compared to Snellen acuities and are not particularly useful for SSA visual function assessment. They are useful for documenting relative changes in severity of vision impairments such as cataracts.
Automated Visual Field analytic devices have been updated so as to combine the functions of automated static threshold testing with automated kinetic
perimetry in single machines. Recently the Humphrey Visual Field machines have become less ubiquitous and Octopus automated field machines have become more popular. They are often preferred by some subspecialists such as neuro-ophthalmologists. SSA needs to prepare training materials and courses for interpretation of Octopus static threshold test plots and automated kinetic perimetry plots. The vision listings need to be changed to allow for their use in
Developments in digital electrophysiologic testing equipment have made it possible for reliable full field and multi-focal ElectroRetinoGraphy (ffERG and
mfERG) to be done in more specialty centers using off-the-shelf devices. Formerly such testing could be done only with complex analog devices that required
full-time technical staff to set up calibration standards. They were supported almost exclusively in university settings.
OCT imaging and analysis are especially useful for retina specialists who use them to document various pathologies such as Cystoid Macular Edema (CME,)
Choroidal Neovascular Membranes (CNV,) retinal holes and retinal membranes. General eye practitioners and glaucoma specialists often rely on OCT to analyze optic nerve changes and retinal nerve fiber layer abnormalities that are signs of disease progression. OCT scanning is relevant to SSA determinations because they can provide objective evidence of pathology consistent with alleged impairments, measured field deficits or acuity loss. Interpretation of OCT imaging and analysis requires more training than can be provided to SSA adjudicators and non-specialist MC’s.
I recommend that the vision listings be changed to mention the utility of OCT to objectively document structural pathology that supports the severity of vision impairment, decreased visual acuity, decreased visual field or decreased threshold sensitivity. OCT imaging should be an optional test modality which can be performed as part of Vision Consultative Examinations (VCE's.) The OCT results would need to be interpreted in the VCE report when the test has been requested.
I recommend that FAF be added to a list of vision system test options which can be requested when appropriate. It is appropriate to perform FAF when there is no objective evidence of pathology that can explain severe vision impairment. Interpreteive services for FAF would need to be performed by the imaging
provider as part of their service.
I recommend that ERG testing (ff ERG and/or mfERG) be made available as a special visual system test modality. It can serve to establish the presence (or
absence) of Retinitis Pigmentosa and other retinal dystrophies. ERG testing would likely be obtainable only from a non-contracted specialty center,
university or other highly specialized eye clinic. Many alleged visual impairments are documented only with acuity and field measurements. These measurements
can readily be falsified by way of poor effort or malingering. An MDI cannot always be established on the basis of a standard VCE. A significant number of
visual disability claims lack objective evidence which is consistent with the degree of measured vision impairment. ERG testing should be made available on
the basis of special request by an MC with interest and expertise in vision cases.
I recommend that a mechanism be put in place to obtain special testing from other than contracted VCE providers. ERG’s and FAF in particular are not likely
to be available from VCE providers. They would need to be obtained from subspecialty providers. Credentialling of such providers would need to be done on a case-by-case basis. They would need to be appropriately equipped, willing and have a well established reputation for subspecialty excellence. They would need service and payment agreements different from contracted providers since they would not be asked to provide disability opinions; only to provide test results and interpretation of medical significance that is meaningful to MC’s with expert understanding of eye disease