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Several techniques have been developed to measure the thickness of the optic nerve/retinal nerve fiber layer (RNFL) as a method to diagnose and monitor glaucoma. Measurement of ocular blood flow is also being evaluated as a diagnostic and management tool for glaucoma.
Glaucoma is a disease characterized by degeneration of the optic nerve (optic disc). Elevated intraocular pressure has long been thought to be the primary etiology, but the relationship between intraocular pressure and optic nerve damage varies among patients, suggesting a multifactorial origin. For example, some patients with clearly elevated intraocular pressure will show no damage to the optic nerve, while other patients with marginal or no pressure elevation will nonetheless show optic nerve damage. The association between glaucoma and other vascular disorders, such as diabetes or hypertension, suggests vascular factors may play a role in glaucoma. Specifically, it has been hypothesized that reductions in blood flow to the optic nerve may contribute to the visual field defects associated with glaucoma.
A comprehensive ophthalmologic exam is required for the diagnosis of glaucoma, but no single test is adequate for establishing the diagnosis. A comprehensive ophthalmologic examination includes an examination of the optic nerve by fundoscopy, evaluation of visual fields, and measurement of ocular pressure. The presence of characteristic changes in the optic nerve or abnormalities in visual field, together with increased IOP, is sufficient for a definitive diagnosis. However, some patients will show ophthalmologic evidence of glaucoma with normal IOPs, therefore an elevated IOP is not essential for diagnosis.
Conventional management of the patient with glaucoma involves drug therapy to control elevated intraocular pressures and serial evaluation of the optic nerve to follow disease progression. Standard methods of evaluation include careful direct examination of the optic nerve using the ophthalmoscopy or stereophotography, or evaluation of visual fields. There is interest in developing more objective, reproducible techniques both to document optic nerve damage and to detect early changes in the optic nerve and retinal nerve fiber layer (RNFL) before the development of permanent visual field deficits. Specifically, evaluating changes in the thickness of the retinal nerve fiber layer has been investigated as a technique to diagnose and monitor glaucoma. In addition, there is interest in measuring ocular blood flow as a diagnostic and management tool for glaucoma. A variety of new techniques have been developed, as described below:
1. Techniques to Evaluate the Optic Nerve/Retinal Nerve Fiber Layer (Note: This policy only addresses uses of these techniques related to glaucoma.)
A. Confocal Scanning Laser Ophthalmoscopy
Confocal scanning laser ophthalmoscopy (CSLO) is a laser-based image acquisition technique, which is intended to improve the quality of the examination compared to standard ophthalmologic examination. A laser is scanned across the retina along with a detector system. Only a single spot on the retina is illuminated at any time, resulting in a high-contrast image of great reproducibility that can be used to estimate the thickness of the RNFL. In addition, this technique does not require maximal mydriasis, which may be a problem in patients with glaucoma. The Heidelberg Retinal Tomography is probably the most common example of this technology.
B. Scanning Laser Polarimetry
The RNFL is birefringent, causing a change in the state of polarization of a laser beam as it passes. A 780-nm diode laser is used to illuminate the optic nerve. The polarization state of the light emerging from the eye is then evaluated and correlated with RNFL thickness. Unlike CSLO, scanning laser polarimetry (SLP) can directly measure the thickness of the RNFL. GDx® is a common example of a scanning laser polarimeter. GDx® contains a normative database and statistical software package to allow comparison to age-matched normal subjects of the same ethnic origin. The advantages of this system are that images can be obtained without pupil dilation, and evaluation can be done in about 10 minutes. Current instruments have added enhanced and variable corneal compensation technology to account for corneal polarization.
C. Optical Coherence Tomography
Optical coherence tomography (OCT) uses near-infrared light to provide direct cross-sectional measurement of the RNFL. The principles employed are similar to those used in B-mode ultrasound except light, not sound, is used to produce the 2-dimensional images. The light source can be directed into the eye through a conventional slit-lamp biomicroscope and focused onto the retina through a typical 78-diopter lens. This system requires dilation of the patient’s pupil. OCT® is an example of this technology.
2. Pulsatile Ocular Blood Flow
The pulsatile variation in ocular pressure results from the flow of blood into the eye during cardiac systole. Pulsatile ocular blood flow can thus be detected by the continuous monitoring of intraocular pressure. The detected pressure pulse can then be converted into a volume measurement using the known relationship between ocular pressure and ocular volume. Pulsatile blood flow is primarily determined by the choroidal vessels, particularly relevant to patients with glaucoma, since the optic nerve is supplied in large part by the choroidal circulation.
3. Doppler Ultrasonography
Color Doppler imaging has also been investigated as a technique to measure the blood velocity in the retinal and choroidal arteries.
In 2012, The iExaminer™ (Welch Allyn) received marketing clearance from the U.S. Food and Drug Administration (FDA). The iExaminer consists of a hardware adapter and associated software (iPhone® App) to capture, store, send and retrieve images from the Welch Allyn PanOptic™ Ophthalmoscope using an iPhone®.
POLICYAnalysis of the optic nerve (retinal nerve fiber layer) in the diagnosis and evaluation of patients with glaucoma or glaucoma suspects may be considered medically necessary when using scanning laser ophthalmoscopy, scanning laser polarimetry, and optical coherence tomography.
The measurement of ocular blood flow, pulsatile ocular blood flow or blood flow velocity with Doppler ultrasonography is considered investigational in the diagnosis and follow-up of patients with glaucoma.
POLICY EXCEPTIONSFederal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.
POLICY GUIDELINESInvestigative service is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized by certifying boards and/or approving or licensing agencies or published peer review criteria as standard, effective medical practice for the treatment of the condition being treated and as such therefore is not considered medically necessary.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.
POLICY HISTORY5/1998: Approved by Medical Policy Advisory Committee (MPAC)
4/12/2001: Managed Care Requirements deleted
5/2001: Reviewed by MPAC; investigational status remains
2/7/2002: Investigational definition added
5/2/2002: Type of Service and Place of Service deleted
5/29/2002: Code Reference section completed
11/2002: Reviewed by MPAC; Scanning Laser Polarimetry (SLP) changed to medically necessary
7/2003: Reviewed by MPAC; "Description" section revised to be consistent with BCBSA, scanning laser ophthalmoscopy and optical coherence tomography are medically necessary for high risk individuals, scanning laser ophthalmoscopy, optical coherence tomography and scanning laser polarimetry are considered investigational as a method of monitoring disease progression in patients with glaucoma and as a screening test for glaucoma in the general population, measurement of pulsatile ocular blood flow or blood flow velocity with doppler ultrasonography is considered investigational in the diagnosis and follow-up of patients with glaucoma, FEP exception added
11/1/2004: Code Reference section updated, CPT code 92135 moved to covered, ICD-9 procedure code 88.90 added covered codes, ICD-9 diagnosis code 250.00, 250.01, 250.02, 250.03, 250.10, 250.11, 250.12, 250.13, 250.20, 250.21, 250.22, 250.23, 250.30, 250.31, 250.32, 250.33, 250.40, 250.41, 250.42, 250.43, 250.50, 250.51, 250.52, 250.53, 250.60, 250.61, 250.62, 250.63, 250.70, 250.71, 250.72, 250.73, 250.80, 250.81, 250.82, 250.83, 250.90, 250.91, 250.92, 250.93, 360.21, 362.85, V19.0 added covered codes, ICD-9 diagnosis 365.00, 365.01, 365.02, 365.03, 365.04, 365.10, 365.11, 365.12, 365.13, 365.14, 365.15, 365.20, 365.21, 365.22, 365.23, 365.24, 365.31, 365.32, 365.41, 365.42, 365.43, 365.44, 365.51, 365.52, 365.59, 365.60, 365.61, 365.62, 365.63, 365.64, 365.65, 365.81, 365.82, 365.83, 365.89, 365.9 description revised and moved from non-covered to covered, CPT code 93875 added to non-covered codes
1/10/2005: Code Reference section updated, ICD-9 diagnosis code 362.01, 362.02, 368.40, 368.41, 368.42, 368.43, 368.44, 368.45, 368.46, 368.47 added covered codes, HCPCS S0820 deleted
11/16/2005: Code Reference section updated, ICD9 diagnosis codes 362.03 - 362.07 added
3/17/2006: Policy reviewed, no changes
12/19/2007: Coding updated per 2008 CPT/HCPCS revisions
1/18/2008: Policy reviewed, no changes
9/16/2008: Annual ICD-9 updates effective 10-1-2008 applied
12/31/2008: Code reference section updated per 2009 CPT/HCPCS revisions
08/03/2010: Policy Description revised to remove optic nerve head analyzers. Policy statement revised to remove optic nerve head analyzers and analysis of the optic nerve (retinal nerve fiber layer) in the diagnosis and evaluation of patients with glaucoma or glaucoma suspects may be considered medically necessary when using scanning laser ophthalmoscopy, scanning laser polarimetry, and optical coherence tomography. FEP verbiage revised in Policy Exceptions section. Code Reference section revised to add ICD-9 diagnosis codes to the Covered Codes Table: 115.02, 190.5, 190.6, 224.5, 224.6, 228.03, 360.11, 361.00 - 361.9, 362.00 - 362.9, 363.00 - 363.9, 364.21 - 364.24 and 368.15. A note was revised for CPT Code 33875 in the Non-Covered Codes Table.
03/07/2011: Policy statement updated to add ocular blood flow as investigational. Added new CPT codes 92132, 92133, and 92134 to the Code Reference section.
03/02/2012: Policy reviewed. Deleted outdated references from Sources section.
04/17/2013: Policy reviewed; no changes to policy statement. Added ICD-9 procedure code 38.25 to the Code Reference section and deleted 88.90 from the Code Reference section.
03/18/2014: Policy reviewed; description updated regarding FDA-approved device. Policy statement unchanged.
03/11/2015: Policy description updated with information regarding the comprehensive ophthalmologic exam. Policy statements unchanged.
SOURCE(S)Blue Cross Blue Shield Association policy #9.03.06
CODE REFERENCEThis may not be a comprehensive list of procedure codes applicable to this policy.
The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document.