Medical Policies - Other
Ophthalmologic Techniques For Evaluating Glaucoma
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Analysis of the optic nerve (retinal nerve fiber layer) in the diagnosis and evaluation of patients with glaucoma 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 is considered experimental, investigational and/or unproven in the diagnosis and follow-up of patients with glaucoma.
Monitoring of intraocular pressure for 24 hours or longer, unilateral or bilateral, is considered experimental, investigational and/or unproven using any method of measurement, including but not limited to contact lens sensor technology (e.g., Triggerfish®).
Glaucoma is characterized by degeneration of the optic nerve (optic disc). Elevated intraocular pressure (IOP) has long been thought to be the primary etiology, but the relation between IOP and optic nerve damage varies among patients, suggesting a multifactorial origin. For example, some patients with clearly elevated IOP will show no optic nerve damage, while others with marginal or no pressure elevation will show optic nerve damage. The association between glaucoma and other vascular disorders (e.g., diabetes, 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.
Diagnosis and Management
A comprehensive ophthalmologic exam is required for the diagnosis of glaucoma, but no single test is adequate to establish 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 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 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 RNFL thickness 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 NTG, there is never an increase in IOP. It has been proposed that 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. A variety of techniques have been developed, as described below. (Note: This medical policy only addresses techniques related to the evaluation of the optic nerve, RNFL, blood flow to the retina and choroid in patients with glaucoma and monitoring of IOP for 24 hours or longer).
Techniques to Evaluate the Optic Nerve and RNFL
Confocal Scanning Laser Ophthalmoscopy (CLSO)
CSLO is an image acquisition technique intended to improve the quality of the eye examination compared with 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 RNFL thickness. In addition, this technique does not require maximal mydriasis, which may be problematic in patients with glaucoma. The Heidelberg Retinal Tomograph is probably the most common example of this technology.
Scanning Laser Polarimetry (SLP)
The RNFL is birefringent (or biorefractive), meaning that it causes 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, SLP can directly measure the thickness of the RNFL. GDx® is a common SLP device. GDx contains a normative database and statistical software package that compare scan results with 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 completed in 10 minutes. Current instruments have added enhanced and variable corneal compensation technology to account for corneal polarization.
Optical Coherence Tomography (OCT)
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 analysis software is being developed to include optic nerve head parameters with spectral domain OCT, analysis of macular parameters, and hemodynamic parameters with Doppler OCT and OCT angiography.
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 IOP. The detected pressure pulse can then be converted into a volume measurement using the known relation between ocular pressure and ocular volume. Pulsatile blood flow is primarily determined by the choroidal vessels, particularly relevant to patients with glaucoma, because the optic nerve is supplied in large part by choroidal circulation.
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. (1)
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 to 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.
24-Hour Intraocular Pressure Monitoring
The need for continuous monitoring of glaucoma patients has been recognized for several years. Diurnal fluctuations in IOP represent an independent risk factor for glaucoma disease progression despite normal IOP readings in the office setting. A significant percentage of glaucoma patients have intraocular peaks or target pressure breakthroughs at night or early morning. SENSIMED (Switzerland) manufactures the Triggerfish®, which is a contact lens used for 24-hour monitoring of IOP. The device is a soft hydrophilic single use contact lens, containing passive and active strain gauges embedded in the silicone to monitor fluctuations in diameter of the corneoscleral junction. The output signal sent wirelessly to the SENSIMED Triggerfish® antenna is directly correlated to fluctuations in IOP. The adhesive antenna, worn around the eye is connected to a portable recorder through a thin flexible data cable. The patient wears the SENSIMED Triggerfish® up to 24 hours and assumes normal activities including sleep periods. When the patient returns to his doctor, the data is transferred from the recorder to the practitioner's computer via Bluetooth technology for immediate analysis. (2)
Other types of devices are also being developed for 24-hour IOP monitoring.
A number of confocal scanning laser ophthalmoscopy, scanning laser polarimetry, and OCT devices have been cleared by the U.S. Food and Drug Administration (FDA) through the 510(k) process for imaging the posterior eye segment. For example, the RTVue XR OCT Avanti™ (Optovue) is an OCT system indicated for the in vivo imaging and measurement of the retina, retinal nerve fiber layer, and optic disc as a tool and aid in the clinical diagnosis and management of retinal diseases. The RTVue XR OCT Avanti™ with Normative Database is a quantitative tool for comparing retina, retinal nerve fiber layer, and optic disk measurements in the human eye to a database of known normal subjects. It is intended as a diagnostic device to aid in the detection and management of ocular diseases. In 2016, the RTVue XR OCT with Avanti™ with AngioVue™ Software was cleared by the FDA through the 510(k) process (K153080) as an aid in the visualization of vascular structures of the retina and choroid. FDA product code: HLI, OBO.
In 2012, the iExaminer™ (Welch Allyn) was cleared for marketing by the FDA through the 510(k) process. The iExaminer™ consists of a hardware adapter and associated software (iPhone® App) to capture, store, send, and retrieve images from the PanOptic™ Ophthalmoscope (Welch Allyn) using an iPhone®. FDA product code: HKI.
In 2016, the SENSIMED Triggerfish® (Sensimed AG, Switzerland) received marketing clearance from the FDA through the de novo process. The FDA classifies the SENSIMED Triggerfish®, and substantially equivalent devices of this generic type into Class II under the generic name, Diurnal Pattern Recorder System. A diurnal pattern recorder system is a non-implantable, prescription device incorporating a telemetric sensor to detect changes in ocular dimension for monitoring diurnal patterns of IOP fluctuations. Currently, the Triggerfish® contact lens sensor (CLS) is the only commercially available device that has been shown to be able to provide 24 hour IOP data. FDA product code: PLZ. (3)
This medical policy was originally created in January 2009 and has been updated regularly with searches of the MEDLINE database. The most recent literature update was performed through June 30, 2017. Following is a summary of the key literature to date.
Assessment of a diagnostic technology typically focuses on 3 categories of evidence:
1) its technical performance (test-retest reliability or interrater reliability); 2) diagnostic accuracy (sensitivity, specificity, and positive and negative predictive value) in relevant populations of patients; and 3) demonstration that the diagnostic information can be used to improve patient outcomes. In addition, subsequent use of a technology outside of the investigational setting may also be evaluated. These categories of evidence, although not always evaluated in sequence, can be considered similar to the 4 phases of therapeutic studies.
The use of various techniques of retinal nerve fiber layer (RNFL) analysis (confocal scanning laser ophthalmoscopy [CSLO], scanning laser polarimetry [SLP], optical coherence tomography [OCT]) for the diagnosis and management of glaucoma was addressed by two Blue Cross Blue Shield Association (BCBSA) Technology Evaluation Center (TEC) Assessments (2001,  2003 ). Literature searches focusing on longitudinal results have been performed since the 2003 BCBSA TEC Assessment.
Imaging of the Optic Nerve and RNFL
Clinical Context and Test Purpose
The diagnosis and monitoring of optic nerve damage are essential for evaluating the progression of glaucoma and determining appropriate treatment.
The question addressed in this medical policy is: Do imaging techniques for the optic nerve and RNFL improve diagnosis and monitoring?
The following PICOTS were used to select literature to inform this medical policy:
The relevant population is patients with glaucoma or who are suspected to have glaucoma being evaluated for diagnosis and monitoring of glaucoma progression.
The technologies of interest for assessment of the optic nerve and RNFL include CLSO, SLP, and OCT. They are considered add-on tests to the standard clinical evaluation.
There is no single criterion standard for the diagnosis of glaucoma. This diagnosis is made from a combination of visual field testing, intraocular pressure (IOP) measurement, and optic nerve and RNFL assessment by an ophthalmologist.
Relevant outcomes include the clarity of the images and how reliable the test is at evaluating the optic nerve and nerve fiber layer changes. Demonstration that the information can be used to improve patient outcomes is essential for determining the utility of an imaging technology. Although direct evidence on the impact of the imaging technology from controlled trials would be preferred, in most cases, a chain of evidence needs to be constructed to determine whether there is a tight linkage between the technology and improved health outcomes. The outcomes relevant to this evidence review are IOP, loss of vision, and changes in IOP-lowering medications used to treat glaucoma.
For patients with manifest glaucoma, the relevant period of follow-up is the immediate diagnosis of glaucoma. For patients with suspected glaucoma, longer term follow-up would be needed to detect changes in visual field or RNFL. Clinical utility might be demonstrated by a change in the management and reduction in glaucoma progression across follow-up.
Patients may be self-referred, referred by optometrists, or referred by a general ophthalmologist to a glaucoma specialist. These procedures can be performed in an ophthalmologist’s office.
We did not identify studies reporting on the technical performance of imaging techniques for the optic nerve and RNFL.
In 2012, the Agency for Healthcare Research and Quality published a comparative effectiveness review of screening for glaucoma. (6) Included were randomized controlled trials (RCTs), quasi-RCTs, observational cohort and case-control studies, and case series with more than 100 participants. The interventions evaluated included ophthalmoscopy, fundus photography or computerized imaging (OCT, retinal tomography, SLP), pachymetry (corneal thickness measurement), perimetry, and tonometry. No evidence was identified that addressed whether an open-angle glaucoma screening program led to a reduction in IOP, less visual impairment, reduction in visual field loss or optic nerve damage, or improvement in patient-reported outcomes. No evidence was identified on harms of a screening program. Over 100 studies were identified on the diagnostic accuracy of screening tests. However, due to the lack of a definitive diagnostic reference standard and heterogeneity in study designs, synthesis of results could not be completed.
A 2015 Cochrane review assessed the diagnostic accuracy of optic nerve head and nerve fiber layer imaging for glaucoma. (7) Included were 103 case-control studies and 3 cohort studies (total N=16,260 eyes) that evaluated the accuracy of recent commercial versions of OCT (spectral domain), Heidelberg Retinal Tomograph (HRT) III, or SLP (GDx VCC or ECC) for diagnosing glaucoma. The population was patients who had been referred for suspected glaucoma, typically due to an elevated IOP, abnormal optic disc appearance, and/or an abnormal visual field identified in primary eye care. Population-based screening studies were excluded. Most comparisons examined different parameters within the 3 tests, and the parameters with the highest diagnostic odds ratio were compared. The 3 tests (OCT, HRT, SLP) had similar diagnostic accuracy. Specificity was close to 95%, while sensitivity was 70%. Because a case-control design with healthy participants and glaucoma patients was used in nearly all studies, concerns were raised about the potential for bias, overestimation of accuracy, and applicability of the findings to clinical practice.
Effect on Health Outcomes
A technology assessment issued by American Academy of Ophthalmology (AAO) in 2007 reviewed 159 studies, published between January 2003 and February 2006, evaluating optic nerve head and RNFL devices used to diagnose or detect glaucoma progression. (8) The assessment concluded: “The information obtained from imaging devices is useful in clinical practice when analyzed in conjunction with other relevant parameters that define glaucoma diagnosis and progression.” Management changes for patients diagnosed with glaucoma may include the use of IOP-lowering medications, monitoring for glaucoma progression, and potentially surgery to slow the progression of glaucoma.
Section Summary: Imaging of the Optic Nerve and RNFL
Numerous studies and systematic reviews have described findings from patients with glaucoma using CSLO, SLP, and OCT. Although the specificity in these studies was high, it is likely that accuracy was overestimated due to the case-control designs used in the studies. The literature and specialty society guidelines have indicated that optic nerve analysis using CSLO, SLP, and OCT are established add-on tests that can be used with other established tests to improve the diagnosis and direct management of patients with glaucoma and those who are glaucoma suspects. Management changes for patients diagnosed with glaucoma may include the use of IOP-lowering medications, monitoring for glaucoma progression, and potentially surgery.
Evaluation Of Ocular Blood Flow
Clinical Context and Test Purpose
The diagnosis and monitoring of optic nerve damage are essential for evaluating the progression of glaucoma and determining appropriate treatment. Measurement of ocular blood flow has been studied as a technique to evaluate patients with glaucoma or suspected glaucoma.
The question addressed in this medical policy is: Do the techniques described below for assessing ocular blood flow improve diagnosis and monitoring? One potential application is the early detection of normal tension glaucoma. (9)
The following PICOTS were used to select literature to inform this medical policy:
The relevant patient population is patients with glaucoma or suspected glaucoma who are being evaluated for diagnosis and monitoring of glaucoma progression. These tests may have particular utility for normal tension glaucoma (NTG).
The technologies of interest for assessment of the optic nerve and optic nerve layer include color Doppler imaging (CDI), Doppler Fourier domain OCT, laser Doppler velocimetry, confocal scanning laser Doppler flowmetry, and retinal functional imager.
There is no other criterion standard for the diagnosis of glaucoma. The diagnosis of glaucoma is made from a combination of visual field testing, IOP measurements, and optic nerve and RNFL assessment.
Relevant outcomes include the reliability of the test for evaluating ocular blood flow and the association between ocular blood flow parameters and glaucoma progression. Demonstration that the information can be used to improve patient outcomes is essential to determining the utility of a diagnostic technology. Although direct evidence on the impact of the imaging technology from controlled trials would be preferred, in most cases, a chain of evidence is needed to determine whether there is a tight linkage between the technology and improved health outcomes. The outcomes relevant to this evidence review are IOP, loss of vision, and changes in IOP-lowering medications used to treat glaucoma.
Longitudinal studies are needed to evaluate whether changes in blood flow are predictive of future visual loss.
Many of these procedures are performed with specialized equipment. While reports of use are longstanding (e.g., Bafa et al.  ), investigators have commented on the complexity of these parameters (11) and have noted that many of these technologies are not commonly used in clinical settings. (12)
We did not identify studies reporting on the technical performance of ocular blood flow evaluation techniques.
In 2016, Abegao Pinto et al. reported the results from the prospective, cross-sectional, case-control, Leuven Eye Study, which included 614 individuals who had primary open-angle glaucoma (POAG; n=214), NTG (n=192), ocular hypertension (n=27), suspected glaucoma (n=41), or healthy controls (n=140). (13) The objective of this study was to identify the blood flow parameters most highly associated with glaucoma using technology commonly available in an ophthalmologist’s office or hospital radiology department. Assessment of ocular blood flow included CDI, retinal oximetry, dynamic contour tonometry, and OCT enhanced-depth imaging of the choroid. The glaucoma groups had higher perfusion pressure compared to controls (p<0.001), with lower velocities in both central retinal vessels (p<0.05), and choroidal thickness asymmetries. The NTG group, but not the POAG group, had higher retinal venous saturation compared to healthy controls (p=0.005). There were no significant differences in macular scans. The diagnostic accuracy or effects on health outcomes were not addressed.
A 2011 study reported on CDI in normal and glaucomatous eyes. (14) Using data from other studies, a weighted mean was derived for the peak systolic velocity, end-diastolic velocity, and Pourcelot Resistive Index in the ophthalmic, central retinal, and posterior ciliary arteries. Data from 3061 glaucoma patients and 1072 controls were included. Mean values for glaucomatous eyes were within 1 SD of the values for controls for most CDI parameters. Methodologic differences created interstudy variance in CDI values, complicating the construction of a normative database and limiting its utility. The authors noted that because the mean values for glaucomatous and normal eyes had overlapping ranges, caution should be used when classifying glaucoma status based on a single CDI measurement.
Effect on Health Outcomes
The clinical utility of techniques to evaluate ocular blood flow is similar to the other imaging techniques. The objective is to improve the diagnosis and direct management of patients with glaucoma or suspected glaucoma. Measures of ocular blood flow may have particular utility for the diagnosis and monitoring of NTG.
The only longitudinal study identified was a 2012 study by Calvo et al. on the predictive value of retrobulbar blood flow velocities in a prospective series of 262 who were glaucoma suspect. (15) At baseline, all participants had normal visual field, increased IOP (mean, 23.56 mm Hg), and glaucomatous optic disc appearance. Blood flow velocities were measured by CDI during the baseline examination, and conversion to glaucoma was assessed at least yearly according to changes observed with CLSO. During the 48-month follow-up, 36 (13.7%) patients developed glaucoma and 226 did not. Twenty (55.5%) of those who developed glaucoma also showed visual field worsening (moderate agreement, κ=0.38). Mean end-diastolic and mean velocity in the ophthalmic artery were significantly reduced at baseline in subjects who developed glaucoma compared with subjects who did not.
Section Summary: Evaluation of Ocular Blood Flow
Techniques to measure ocular blood flow or ocular blood velocity are being evaluated for the diagnosis of glaucoma. Data for these techniques remain limited. Current literature focuses on which technologies are most reliably associated with glaucoma. Literature reviews have not identified studies whether these technologies improve the diagnosis of glaucoma or whether measuring ocular blood flow in patients with glaucoma or suspected glaucoma improves health outcomes.
24-Hour Intraocular Pressure Monitoring
In 2012, Mansouri and colleagues (16) aimed to examine the safety, tolerability, and reproducibility of IOP patterns during continuous 24-hour IOP monitoring with a contact lens sensor. Forty patients suspected of having glaucoma (n=21) or with established glaucoma (n=19) were evaluated. Patients participated in two 24-hour IOP monitoring sessions (S1 and S2) at a 1-week intervals using Triggerfish CLS. Patients pursued daily activities, and sleep behavior was not controlled. Incidence of adverse events and tolerability (visual analog scale [VAS]score) were assessed. Reproducibility of signal patterns was assessed using Pearson correlations. The mean (SD) age of the patients was 55.5(15.7) years, and 60% were male. Main adverse events were blurred vision (82%), conjunctival hyperemia (80%), and superficial punctate keratitis (15%). The mean SD VAS score was 27.2(18.5) mm in S1 and 23.8(18.7) mm in S2 (P=.22). The overall correlation between the 2 sessions was 0.59 (0.51 for no glaucoma medication and 0.63 for glaucoma medication) (P=.12). Mean SD positive linear slopes of the sensor signal from wake to 2 hours into sleep were detected in both sessions for the no glaucoma medication group but not for the glaucoma medication group. Repeated use of the contact lens sensor demonstrated good safety and tolerability. The recorded IOP patterns showed fair to good reproducibility, suggesting that data from continuous 24-hour IOP monitoring may be useful in the management of patients with glaucoma.
In 2014, Hollo et al. (17) reported the results of a trial which evaluated 24-hour continuous IOP monitoring with a telemetric CLS to detect prostaglandin-induced IOP reduction. A total of 9 individuals with ocular hypertensive and primary open-angle glaucoma were washed out from IOP-lowering medication for 6 weeks. One study eye per participant underwent 3 baseline 24-hour measurement curves 4 days apart: 2 curves employing continuous monitoring with a CLS and 1 curve using Goldmann applanation tonometry (GAT). Subsequently, the participants underwent travoprost monotherapy for a total of 3 months. Continuous IOP pressure monitoring using the CLS and GAT curves were repeated on the study eyes under treatment at the end of the third month. The 24-hour GAT IOP (mean ±SD) diminished from 22.91 ± 5.11 to 18.24 ± 2.49 mmHg (p<0.001). In contrast, the means of the 3 CLS curves demonstrated no significant difference (152.94, 142.35, and 132.98 au, p=0.273). The authors concluded that the continuous monitoring of IOP utilizing the CLS cannot be clinically used to monitor changes in IOP induced by topical medication in glaucoma, and has limited value in identification of transient IOP elevation periods.
In 2015, Mansouri et al. (18) evaluated the efficacy of CLS for monitoring 24-hour IOP related short-term patterns and compare with IOP obtained by pneumatonometry. This prospective clinical trial involved 31 healthy volunteers and 2 glaucoma patients that were monitored for 24 hours in a sleep laboratory. One randomly selected eye was fitted with a CLS (Triggerfish, Switzerland). In the contralateral eye, IOP measurements were taken using a pneumatonometer every 2 hours with subjects in the habitual body positions. Heart rate (HR) was measured 3 times during the night for periods of 6 minutes separated by 2 hours. Performance of CLS was defined in two ways: 1) recording the known pattern of IOP increase going from awake (sitting position) to sleep (recumbent), defined as the wake/sleep (W/S) slope and 2) accuracy of the ocular pulse frequency (OPF) concurrent to that of the HR interval. Strength of association between overall CLS and pneumatonometer curves was assessed using coefficients of determination (R2). The W/S slope was statistically significantly positive in both eyes of each subject (CLS, 57.0 ± 40.5 mVeq/h, p<0.001 and 1.6 ± 0.9 mmHg/h, p<0.05 in the contralateral eye). In all, 87 CLS plots concurrent to the HR interval were evaluated. Graders agreed on evaluability for OPF in 83.9% of CLS plots. Accuracy of the CLS to detect the OPF was 86.5%. Coefficient of correlation between CLS and pneumatonometer for the mean 24-h curve was R2 = 0.914. CLS measurements compare well to the pneumatonometer and may be of practical use for detection of sleep-induced IOP changes. The CLS also can detect ocular pulsations with good accuracy in a majority of eyes.
At this time, no published long term RCTs are available that would prompt reconsideration of the coverage statement, which remains unchanged.
Ongoing And Unpublished Clinical Trials
Some currently unpublished trials that might influence this medical policy are listed in Table 1.
Table 1. Summary of Key Trials
Measurement of Ocular Tensional Fluctuation by Triggerfish Lens Before and After Cataract Surgery in Patients With Exfoliative Glaucoma
Table Key: NCT: national clinical trial.
Practice Guidelines And Position Statements
American Academy of Ophthalmology (AAO)
The AAO 2015 preferred practice patterns on primary open-angle glaucoma (POAG) suspect and POAG both recommended evaluating the optic nerve and retinal nerve fiber layer. (21)
The documents stated that “Although they are distinctly different methodologies, stereoscopic disc photographs and computerized images of the nerve are complementary with regard to the information they provide the clinician who must manage the patient.” The guidelines described 3 types of computer-based imaging devices (CLSO, SLP, OCT) currently available for glaucoma, which are similar in their ability to distinguish glaucoma from controls and noted that “computer-based digital imaging of the ONH [optic nerve head] and RNFL [retinal nerve fiber layer] is routinely used to provide quantitative information to supplement the clinical examination of the optic nerve…. One rationale for using computerized imaging is to distinguish glaucomatous damage from eyes without glaucoma when thinning of the RNFL is measured, thereby facilitating earlier diagnosis and detection of optic nerve damage”. In addition, AAO concluded that, as device technology evolves, the performance of diagnostic imaging devices is expected to improve.
In 2016, AAO (22) updated their guideline and states” statistical analysis is unable to determine whether perfusion pressure is associated with glaucoma because of its individual components (systolic blood pressure, diastolic blood pressure, or IOP), a combination of these components, or an interaction between these components. Further research is needed”.
National Institute for Health Research (NHS)
A 2012 technology brief funded by the National Institute for Health Research focused on the Triggerfish® device and concluded (23): “Further research into the relationship between fluctuations in intraocular pressure and the glaucoma disease process is needed. The need for further studies investigating the reproducibility and accuracy of the SENSIMED Triggerfish® measurements in a large number of patients has also been suggested.”
Summary Of Evidence
For individuals with glaucoma who receive imaging of the optic nerve and retinal nerve fiber layer, the evidence includes studies on diagnostic accuracy. Relevant outcomes are test accuracy, symptoms, morbid events, functional outcomes, and medication use. Confocal scanning laser ophthalmoscopy (CSLO), scanning laser polarimetry (SLP), and optical coherence tomography (OCT) can be used to evaluate the optic nerve and retinal nerve fiber layer in patients with glaucoma and suspected glaucoma. Numerous articles have described findings from patients with known and suspected glaucoma using CSLO, SLP, and OCT. These studies have reported that abnormalities may be detected on these examinations before functional changes are noted. The literature and specialty society guidelines have indicated that optic nerve analysis using CSLO, SLP, and OCT are established add-on tests that may be used to diagnose and manage patients with glaucoma and suspected glaucoma. These
results are often considered along with other findings to make diagnostic and therapeutic decisions about glaucoma care, including use of topical medication, monitoring, and surgery to lower intraocular pressure (IOP). Thus, accurate diagnosis of glaucoma would be expected to reduce the progression of glaucoma. The evidence is sufficient to determine that the technology results in a meaningful improvement in the net health outcome.
For individuals with 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 on the technical performance of these tests (e.g., test-retest reliability), 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, i.e., they may help explain why patients with similar levels of IOP 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 the effects of the technology on health outcomes.
For individuals with glaucoma, there are no published clinical studies that compare the rates of glaucoma progression in individuals who underwent continuous monitoring of IOP with individuals who are monitored using the current standard practice. In addition, peer-reviewed studies consist of small study populations and lack long-term follow-up. Additional long term adequately powered RCTs with sufficiently large sample sizes are needed to determine the effects of this technology on health outcomes.
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92133, 92134, 0198T, 0329T
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1. Mohindroo C, Ichhpujani P, Kumar S. Current imaging modalities for assessing ocular blood flow in glaucoma. J Curr Glaucoma Pract. Sep-Dec 2016; 10(3):104-112. PMID 27857490
2. SENSIMED Triggerfish® - Continuous IOP Monitoring. SENSIMED AG. Switzerland. Available at <www.sensimed.ch> (accessed 2017 July 7).
3. U. S. Food and Drug Administration (FDA) - SENSIMED Triggerfish®. Center for Devices and Radiologic Health (2016 April 21). Available at <http://www.accessdata.fda.gov> (accessed 2017 July 7).
4. Blue Cross and Blue Shield Technology Evaluation Center (TEC). Retinal nerve fiber analysis for the diagnosis and management of glaucoma. TEC Assessments. 2001; Volume 16:Tab 13.
5. Blue Cross and Blue Shield Technology Evaluation Center (TEC). Retinal nerve fiber layer analysis for the diagnosis and management of glaucoma. TEC Assessments. 2003; Volume 18:Tab 7.
6. Ervin AM, Boland MV, Myrowitz EH, et al. Screening for Glaucoma: Comparative Effectiveness. Comparative Effectiveness Review No. 59 (AHRQ Publication No. 12-EHC037-EF) Rockville, MD: Agency for Healthcare Research and Quality; 2012 April
7. Michelessi M, Lucenteforte E, Oddone F, et al. Optic nerve head and fibre layer imaging for diagnosing glaucoma. Cochrane Database Syst Rev. 2015(11):CD008803. PMID 26618332
8. Lin SC, Singh K, Jampel HD, et al. Optic nerve head and retinal nerve fiber layer analysis: a report by the American Academy of Ophthalmology. Ophthalmology. Oct 2007; 114(10):1937-1949. PMID 17908595
9. Shiga Y, Omodaka K, Kunikata H, et al. Waveform analysis of ocular blood flow and the early detection of normal tension glaucoma. Invest Ophthalmol Vis Sci. Nov 2013; 54(12):7699-7706. PMID 24130177
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19. Huang, D. Functional and Structural Imaging for Glaucoma (FSOCT). In: ClinicalTrials.gov [Internet]. Bethesda (MD): National Library of Medicine (US). 2017. Available at <https://clinicaltrials.gov> NCT01957267. (accessed 2017 July 7)
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|6/15/2018||Reviewed. No changes.|
|9/15/2017||Document updated with literature review. The following change was made in Coverage: 1) Removed “known or suspected” from the medically necessary coverage statement for the analysis of the optic nerve (retinal nerve fiber layer) in the diagnosis and evaluation of patients with glaucoma 2) Removed “with Doppler ultrasonography” from the experimental, investigational and/or unproven coverage statement for the measurement of ocular blood flow, pulsatile ocular blood flow or blood flow velocity.|
|8/15/2016||Document updated with literature review. Coverage unchanged.|
|1/15/2015||Reviewed. No changes.|
|7/1/2013||Document updated with literature review. The following was added to Coverage: Monitoring of intraocular pressure for 24 hours or longer, unilateral or bilateral, is considered experimental, investigational and unproven using any method of measurement, including but not limited to contact lens sensor technology (e.g., Triggerfish®).|
|8/1/2011||Document updated with literature review. The following change was made: 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. CPT/HCPCS code(s) updated.|
|1/1/2009||New medical document|
|Title:||Effective Date:||End Date:|
|Ophthalmologic Techniques For Evaluating Glaucoma||09-15-2017||06-14-2018|
|Ophthalmologic Techniques of Evaluating Glaucoma||08-15-2016||09-14-2017|
|Ophthalmologic Techniques of Evaluating Glaucoma||01-15-2015||08-14-2016|
|Ophthalmologic Techniques of Evaluating Glaucoma||07-01-2013||01-14-2015|
|Ophthalmologic Techniques of Evaluating Glaucoma||08-01-2011||06-30-2013|
|Ophthalmologic Techniques of Evaluating Glaucoma||01-01-2009||07-31-2011|