Measurement of Ocular Blood Flow for Glaucoma Form

500 EXCHANGE STREET, PROVIDENCE, RI 02903-2699 MEDICAL COVERAGE POLICY | 1 (401) 274-4848 WWW.BCBSRI.COM EFFECTIVE DATE: 10|01|2024 POLICY LAST REVIEWED: 04|16|2025 OVERVIEW Measurement of ocular blood flow is being evaluated as a diagnostic tool for glaucoma. MEDICAL CRITERIA Not applicable PRIOR AUTHORIZATION
Not applicable POLICY STATEMENT Medicare Advantage Plans The measurement of ocular blood flow, pulsatile ocular blood flow, or blood flow velocity is not covered in the diagnosis and follow-up of patients with glaucoma as the evidence is insufficient to determine that the technology results in an improvement in the net health outcome. Commercial Products The measurement of ocular blood flow, pulsatile ocular blood flow, or blood flow velocity is considered not medically necessary in the diagnosis and follow-up of patients with glaucoma as the evidence is insufficient to determine that the technology results in an improvement in the net health outcome. COVERAGE Benefits may vary between groups/contracts. Please refer to the appropriate Benefit Booklet, Evidence of Coverage, or Subscriber Agreement for applicable diagnostic testing and not medically necessary benefits/coverage. BACKGROUND Diagnosis and Management 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 assessment of the optic nerve, 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 intraocular pressure (IOP), is sufficient for a definitive diagnosis. However, some patients will show ophthalmologic evidence of glaucoma with normal IOPs. These cases of normal tension glaucoma (NTG) are considered to be a type of primary open-angle glaucoma (POAG). Angle-closure glaucoma is another type of glaucoma associated with an increase in IOP. The increased IOP in angle-closure glaucoma arises from a reduction in aqueous outflow from the eye due to a closed angle in the anterior chamber. Conventional management of patients with glaucoma principally involves drug therapy to control elevated IOPs, and serial evaluation of the optic nerve to follow disease progression. Standard methods of evaluation include careful direct examination of the optic nerve using ophthalmoscopy or stereo photography, 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 RNFL has been investigated as a technique to diagnose and monitor glaucoma. However, IOP reduction is not effective in decreasing disease progression in a significant number of patients, and in patients with normal-tension glaucoma (NTG), there is never an increase in IOP. It has been proposed that Medical Coverage Policy | Measurement of Ocular Blood Flow for Glaucoma

500 EXCHANGE STREET, PROVIDENCE, RI 02903-2699 MEDICAL COVERAGE POLICY | 2 (401) 274-4848 WWW.BCBSRI.COM

vascular dysregulation is a significant cause of damage to the RNFL, and there is interest in measuring ocular blood flow as both a diagnostic and a management tool for glaucoma. Changes in blood flow to the retina and choroid may be particularly relevant for diagnosis and treatment of NTG.

Techniques to Measure Ocular Blood Flow A number of techniques have been developed to assess ocular blood flow. They include laser speckle flowgraphy, color Doppler imaging, Doppler Fourier domain OCT, laser Doppler velocimetry, confocal scanning laser Doppler flowmetry, and retinal functional imaging.

Laser Speckle Flowgraphy Laser speckle is detected when a coherent light source such as laser light is dispersed from a diffusing surface such as retinal and choroidal vessels and the circulation of the optic nerve head. The varying patterns of light can be used to determine red blood cell velocity and retinal blood flow. However, due to differences in the tissue structure in different eyes, flux values cannot be used for comparisons between eyes. This limitation may be overcome by subtracting background choroidal blood flow results from the overall blood flow results in the region of interest.

Color Doppler Imaging Color Doppler imaging has also been investigated as a technique to measure the blood flow velocity in the retinal and choroidal arteries. This technique delivers ultrasound in pulsed Doppler mode with a transducer set on closed eyelids. The examination takes 30 to 40 minutes and is most effective for the mean velocity of large ophthalmic vessels such as the ophthalmic artery, the central retinal artery, and the short posterior ciliary arteries. However, total blood flow cannot be determined with this technique, and imaging is highly dependent on probe placement.

Doppler Fourier Domain OCT Doppler Fourier domain OCT is a noncontact imaging technique that detects the intensity of the light scattered back from erythrocytes as they move in the vessels of the ocular tissue. This induces a frequency shift that represents the velocity of the blood in the ocular tissue.

Laser Doppler Velocimetry Laser Doppler velocimetry compares the frequency of reflected laser light from a moving particle with stationary tissue.

Confocal Scanning Laser Doppler Flowmetry Confocal scanning laser Doppler flowmetry combines laser Doppler flowmetry with confocal scanning laser tomography. Infrared laser light is used to scan the retina, and the frequency and amplitude of Doppler shifts are determined from the reflected light. Determinations of blood velocity and blood volume are used to compute the total blood flow and create a physical map of retinal flow values.

For individuals who have glaucoma or suspected glaucoma who receive evaluation of ocular blood flow, the evidence includes association studies. Relevant outcomes are test accuracy, symptoms, morbid events, functional outcomes, and medication use. Techniques to measure ocular blood flow or ocular blood velocity are used to determine appropriate glaucoma treatment options. The data for these techniques remain limited. Literature reviews have not identified studies addressing whether these technologies improve diagnostic accuracy or whether they improve health outcomes in patients with glaucoma. Some have suggested that these parameters may inform understanding of the variability in visual field changes in patients with glaucoma (ie, they may help explain why patients with similar levels of intraocular pressure develop markedly different visual impairments). However, data on use of ocular blood flow, pulsatile ocular blood flow, and/or blood flow velocity are currently lacking. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

CODING Medicare Advantage Plans and Commercial Products

500 EXCHANGE STREET, PROVIDENCE, RI 02903-2699 MEDICAL COVERAGE POLICY | 3 (401) 274-4848 WWW.BCBSRI.COM

The following CPT code is not covered for Medicare Advantage Plans and not medically necessary for Commercial Products:
0198T Measurement of ocular blood flow by repetitive pressure sampling, with interpretation and report

RELATED POLICIES Not applicable

PUBLISHED Provider Update, June 2025 Provider Update, August 2024 Provider Update, May 2023 Provider Update, August 2022 Provider Update, November 2021

REFERENCES

1. Mohindroo C, Ichhpujani P, Kumar S. Current Imaging Modalities for assessing Ocular Blood Flow in Glaucoma. J CurrGlaucoma Pract. 2016; 10(3): 104-112. PMID 27857490
2. Ervin AM, Boland MV, Myrowitz EH, et al. Screening for Glaucoma: Comparative Effectiveness (ComparativeEffectiveness Review No. 59). Rockville, MD: Agency for Healthcare Research and Quality;
4. Michelessi M, Lucenteforte E, Oddone F, et al. Optic nerve head and fibre layer imaging for diagnosing glaucoma.Cochrane Database Syst Rev. Nov 30 2015; 2015(11): CD008803. PMID 26618332
5. Chou R, Selph S, Blazina I, et al. Screening for Glaucoma in Adults: Updated Evidence Report and Systematic Review forthe US Preventive Services Task Force. JAMA. May 24 2022; 327(20): 1998-2012. PMID 35608575
6. Lin SC, Singh K, Jampel HD, et al. Optic nerve head and retinal nerve fiber layer analysis: a report by the AmericanAcademy of Ophthalmology. Ophthalmology. Oct 2007; 114(10): 1937-49. PMID 17908595
7. Shiga Y, Omodaka K, Kunikata H, et al. Waveform analysis of ocular blood flow and the early detection of normal tensionglaucoma. Invest Ophthalmol Vis Sci. Nov 21 2013; 54(12): 7699-706. PMID 24130177
8. Bafa M, Lambrinakis I, Dayan M, et al. Clinical comparison of the measurement of the IOP with the ocular blood flowtonometer, the Tonopen XL and the Goldmann applanation tonometer. Acta Ophthalmol Scand. Feb 2001; 79(1): 15-8. PMID 11167279
9. Schmidl D, Garhofer G, Schmetterer L. The complex interaction between ocular perfusion pressure and ocular blood flow- relevance for glaucoma. Exp Eye Res. Aug 2011; 93(2): 141-55. PMID 20868686
10. Harris A, Kagemann L, Ehrlich R, et al. Measuring and interpreting ocular blood flow and metabolism in glaucoma. Can JOphthalmol. Jun 2008; 43(3): 328-36. PMID 18443609
11. WuDunn D, Takusagawa HL, Sit AJ, et al. OCT Angiography for the Diagnosis of Glaucoma: A Report by the AmericanAcademy of Ophthalmology. Ophthalmology. Aug 2021; 128(8): 1222-1235. PMID
13. Gu C, Li A, Yu L. Diagnostic performance of laser speckle flowgraphy in glaucoma: a systematic review and meta-analysis. Int Ophthalmol. Nov 2021; 41(11): 3877-3888. PMID 34327617
14. Aizawa N, Yokoyama Y, Chiba N, et al. Reproducibility of retinal circulation measurements obtained using laser speckleflowgraphy-NAVI in patients with glaucoma. Clin Ophthalmol. 2011; 5: 1171-6. PMID 21887100
15. Gardiner SK, Cull G, Fortune B, et al. Increased Optic Nerve Head Capillary Blood Flow in Early Primary Open-AngleGlaucoma. Invest Ophthalmol Vis Sci. Jul 01 2019; 60(8): 3110-3118. PMID 31323681
16. Iida Y, Akagi T, Nakanishi H, et al. Retinal Blood Flow Velocity Change in Parafoveal Capillary after Topical TafluprostTreatment in Eyes with Primary Open-angle Glaucoma. Sci Rep. Jul 10 2017; 7(1): 5019. PMID 28694501
17. Association between mitochondrial DNA damage and ocular blood flow in patients with glaucoma. Br J Ophthalmol. Aug2019; 103(8): 1060-1065. PMID 30190366
18. Kiyota N, Kunikata H, Shiga Y, et al. Relationship between laser speckle flowgraphy and optical coherence tomographyangiography measurements of ocular microcirculation. Graefes Arch Clin Exp Ophthalmol. Aug 2017; 255(8): 1633-1642.PMID 28462456

500 EXCHANGE STREET, PROVIDENCE, RI 02903-2699 MEDICAL COVERAGE POLICY | 4 (401) 274-4848 WWW.BCBSRI.COM

17. Kiyota N, Shiga Y, Suzuki S, et al. The Effect of Systemic Hyperoxia on Optic Nerve Head Blood Flow in Primary Open-Angle Glaucoma Patients. Invest Ophthalmol Vis Sci. Jun 01 2017; 58(7): 3181-3188. PMID 28654983
18. Kiyota N, Kunikata H, Shiga Y, et al. Ocular microcirculation measurement with laser speckle flowgraphy and opticalcoherence tomography angiography in glaucoma. Acta Ophthalmol. Jun 2018; 96(4): e485-e492. PMID 29575676
19. Kobayashi W, Kunikata H, Omodaka K, et al. Correlation of optic nerve microcirculation with papillomacular bundlestructure in treatment naive normal tension glaucoma. J Ophthalmol. 2014; 2014:
20. PMID 25574382
21. Kohmoto R, Sugiyama T, Ueki M, et al. Correlation between laser speckle flowgraphy and optical coherence tomographyangiography measurements in normal and glaucomatous eyes. Clin Ophthalmol. 2019; 13: 1799-1805. PMID 31571818
22. Kuroda F, Iwase T, Yamamoto K, et al. Correlation between blood flow on optic nerve head and structural and functionalchanges in eyes with glaucoma. Sci Rep. Jan 20 2020; 10(1): 729. PMID 31959837
23. Mursch-Edlmayr AS, Luft N, Podkowinski D, et al. Laser speckle flowgraphy derived characteristics of optic nerve headperfusion in normal tension glaucoma and healthy individuals: a Pilot study. Sci Rep. Mar 28 2018; 8(1): 5343. PMID29593269
24. Mursch-Edlmayr AS, Luft N, Podkowinski D, et al. Differences in Optic Nerve Head Blood Flow Regulation in NormalTension Glaucoma Patients and Healthy Controls as Assessed With Laser Speckle Flowgraphy During the Water DrinkingTest. J Glaucoma. Jul 2019; 28(7): 649-654. PMID 30950964
25. Mursch-Edlmayr AS, Pickl L, Calzetti G, et al. Comparison of Neurovascular Coupling between Normal Tension GlaucomaPatients and Healthy Individuals with Laser Speckle Flowgraphy. Curr Eye Res. Nov 2020; 45(11): 1438-1442. PMID32255706
26. Shiga Y, Kunikata H, Aizawa N, et al. Optic Nerve Head Blood Flow, as Measured by Laser Speckle Flowgraphy, IsSignificantly Reduced in Preperimetric Glaucoma. Curr Eye Res. Nov 2016; 41(11): 1447-
27. PMID 27159148
28. Takeyama A, Ishida K, Anraku A, et al. Comparison of Optical Coherence Tomography Angiography andLaser Speckle Flowgraphy for the Diagnosis of Normal-Tension Glaucoma. J Ophthalmol. 2018; 2018:1751857. PMID 29651339
29. Abegão Pinto L, Willekens K, Van Keer K, et al. Ocular blood flow in glaucoma - the Leuven Eye Study.Acta Ophthalmol. Sep 2016; 94(6): 592-8. PMID 26895610
30. Kurysheva NI, Parshunina OA, Shatalova EO, et al. Value of Structural and Hemodynamic Parametersfor the Early Detection of Primary Open-Angle Glaucoma. Curr Eye Res. Mar 2017; 42(3): 411-417.PMID 27341295
31. Witkowska KJ, Bata AM, Calzetti G, et al. Optic nerve head and retinal blood flow regulation duringisometric exercise as assessed with laser speckle flowgraphy. PLoS One. 2017; 12(9): e0184772. PMID28898284
32. Rusia D, Harris A, Pernic A, et al. Feasibility of creating a normative database of colour Doppler imagingparameters in glaucomatous eyes and controls. Br J Ophthalmol. Sep 2011; 95(9): 1193-8. PMID21106991
33. Calvo P, Ferreras A, Polo V, et al. Predictive value of retrobulbar blood flow velocities in glaucomasuspects. Invest Ophthalmol Vis Sci. Jun 22 2012; 53(7): 3875-84. PMID 22589447
34. Gedde SJ, Vinod K, Wright MM, et al. Primary Open-Angle Glaucoma Preferred Practice Pattern®.Ophthalmology. Jan 2021; 128(1): P71-P150. PMID 34933745
35. Gedde SJ, Lind JT, Wright MM, et al. Primary Open-Angle Glaucoma Suspect Preferred PracticePattern®. Ophthalmology. Jan 2021; 128(1): P151-P192. PMID 34933743
36. Mangione CM, Barry MJ, Nicholson WK, et al. Screening for Primary Open-Angle Glaucoma: USPreventive Services Task Force Recommendation Statement. JAMA. May 24 2022; 327(20): 1992-
37. PMID 35608574

500 EXCHANGE STREET, PROVIDENCE, RI 02903-2699 MEDICAL COVERAGE POLICY | 5 (401) 274-4848 WWW.BCBSRI.COM

i

This medical policy is made available to you for informational purposes only. It is not a guarantee of payment or a substitute for your medical judgment in the treatment of your patients. Benefits and eligibility are determined by the member's subscriber agreement or member certificate and/or the employer agreement, and those documents will supersede the provisions of this medical policy. For information on member-specific benefits, call the provider call center. If you provide services to a member which are determined to not be medically necessary (or in some cases medically necessary services which are non-covered benefits), you may not charge the member for the services unless you have informed the member and they have agreed in writing in advance to continue with the treatment at their own expense. Please refer to your participation agreement(s) for the applicable provisions. This policy is current at the time of publication; however, medical practices, technology, and knowledge are constantly changing. BCBSRI reserves the right to review and revise this policy for any reason and at any time, with or without notice. Blue Cross & Blue Shield of Rhode Island is an independent licensee of the Blue Cross and Blue Shield Association. CLICK THE ENVELOPE ICON BELOW TO SUBMIT COMMENTS