Scanning Computerized Ophthalmic Diagnostic Imaging (SCODI) Form

Summary Of Evidence

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Analysis of Evidence

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Medicare will consider scanning computerized ophthalmic diagnostic imaging (SCODI) medically reasonable and necessary in evaluating retinal disorders, glaucoma, and anterior segment disorders as documented in this local coverage determination (LCD).

SCODI includes the following tests:

• Confocal Laser Scanning Ophthalmoscopy (topography) uses stereoscopic videographic digitized images to make quantitative topographic measurements of the optic nerve head and surrounding retina. 
• Scanning Laser Polarimetry (nerve fiber analyzer) measures change in the linear polarization of light (retardation). It uses both a polarimeter (an optical device to measure linear polarization change) and a scanning laser ophthalmoscope, to measure the thickness of the nerve fiber layer of the retina.
• Optical Coherence Tomography (OCT) a non-invasive, non-contact imaging technique.

OCT, especially SCODI, produces high resolution, cross-sectional tomographic images of ocular structures and is used for the evaluation of the optic nerve head, nerve fiber layer, and retina.
Scanning computerized ophthalmic diagnostic imaging allows earlier detection of glaucoma and more sophisticated analysis for ongoing management. These tests also provide more precise methods of observation of the optic nerve head and can more accurately reveal subtle glaucomatous changes over the course of time than visual fields and/or disc photos. This allows earlier and more efficient efforts of treatment toward the disease process.

Indications

Glaucoma
Glaucoma is a leading cause of blindness, and a disease for which treatment methods clearly are available and in common use. Glaucoma also is diagnostically challenging. Almost 50% of glaucoma cases remain undetected. Elevated intraocular pressure (IOP) is a clear risk factor for glaucoma, but over 30% of those suffering from the disease have pressures in the normal range.

Glaucoma commonly causes a spectrum of related eye and vision changes including erosion of the optic nerve and the associated retinal nerve fibers, and loss of peripheral vision. A diagnosis of glaucoma is not made on the basis of a single clinical observation, but instead relies upon analysis of an assemblage of clinical data including optic nerve, retinal nerve fiber, and anterior chamber structures, as well as looking for hemorrhages of the optic nerve, pigment in the anterior chamber, and especially visual field loss. Each of these methods has its own strengths and limitations, thus the dependence upon multiple observations. Careful reliance upon all available clinical data can allow early treatment and can prevent unnecessary end-stage therapies.

SCODI allows earlier detection of those patients with normal tension glaucoma and more sophisticated analysis for ongoing management. Because SCODI detects glaucomatous damage to the nerve fiber layer or optic nerve of the eye, it can distinguish patients with glaucomatous damage irrespective of the status of IOP. It may separate patients with elevated IOP and early glaucoma damage from those without glaucoma.

Technological improvements have rendered SCODI as a valuable diagnostic tool in the diagnosis and treatment of glaucoma. These improvements enable discernment of changes of the optic nerve and nerve fiber layer, even in advanced cases of glaucoma.

It is expected that only two (SCODI) exams/eye/year would be required to manage the patient who has glaucoma or is suspected of having glaucoma.

Retinal Disorders
Retinal disorders are the most common causes of severe and permanent vision loss. SCODI is a valuable tool for the evaluation and treatment of patients with retinal disease, especially macular abnormalities. SCODI is able to detail the microscopic anatomy of the retina and the vitreoretinal interface. SCODI is useful to measure the effectiveness of therapy, and in determining the need for ongoing therapy, or the safety of cessation of that therapy.

Retinal thickness analysis is a non-invasive and non-contact imaging technique that takes direct cross-sectional images of the retina. These high-resolution images capture ocular structures and provide data to create thickness maps of the retina. Retinal thickness is directly correlated to ocular disease, including retinal disorders and glaucoma. In contrast, Scanning Laser Polarimetry is not an appropriate diagnostic technique for the management of retinal disorders.

Long Term Use of Chloroquine and or Hydroxychloroquine
Clinical evidence has shown that long-term use of chloroquine (CQ) and/or hydroxychloroquine (HCQ) can lead to irreversible retinal toxicity. Therefore, these two medications are deemed high risk, and scanning optical coherence tomography may be indicated to provide a baseline prior to starting the medication and as an annual follow-up. Clinical evidence shows that the resolution of time domain OCT instruments is not sufficient to detect early toxic retinal changes. Because of that, spectral domain-optical coherence tomography (SD-OCT) is expected to be used to detect retinal changes that are due to the use of CQ or HCQ.

Anterior Segment Disorders
SCODI may be used to examine the structures in the anterior segment structures of the eye. However, it is still seen as experimental/investigational except in the following:

1. Narrow angle, suspected narrow angle, and mixed narrow and open angle glaucoma 
2. Determining the proper intraocular lens for a patient who has had prior refractive surgery and now requires cataract extraction 
3. Iris tumor 
4. Presence of corneal edema or opacity that precludes visualization or study of the anterior chamber
5. Calculation of lens power for cataract patients who have undergone prior refractive surgery. Payment will only be made for the cataract codes as long as additional documentation is available in the patient record of their prior refractive procedure. Payment will not be made in addition to A-scan or IOL master.

Limitations
The following procedures would generally not be necessary with SCODI. When medically needed the same day, documentation must justify the procedures.

1. Fundus photography with interpretation and report
2. Ophthalmoscopy extended with retinal drawing (e.g., For retinal detachment, melanoma) with interpretation and report initial
3. Subsequent ophthalmoscopy
4. B-scan (with or without superimposed non-quantitative A-scan)