Compliance with the provisions in this policy may be monitored and addressed
through post payment data analysis and subsequent medical review audits.  
  
**History/Background and/or General Information**  
  
 **Glaucoma**  
  
Glaucoma is a leading cause of blindness, and a disease for which treatment
methods clearly are available and in common use. Scanning computerized
ophthalmic diagnostic imaging (SCODI) allows for early detection of
glaucomatous damage to the nerve fiber layer or optic nerve of the eye. It is
the goal of these diagnostic imaging tests to discriminate among patients with
normal intraocular pressure (IOP) who have glaucoma, patients with elevated
IOP who have glaucoma, and patients with elevated IOP who do not have
glaucoma. These tests can also provide precise methods of observation of the
optic nerve head and can more accurately reveal subtle glaucomatous changes
over the course of follow-up exams than visual field and/or disc photos. This
can allow earlier and more efficient treatment of the disease process. The
severity of glaucoma damage can be estimated as mild, moderate, severe or
indeterminate.  
  
 **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 vitreo-retinal interface.
SCODI is useful to measure the effectiveness of therapy, in determining the
need for ongoing therapy, or cessation of therapy.  
  
The retina is a complex tissue in the back of the eye that contains
specialized photoreceptor cells called rods and cones. The photoreceptors
connect to a network of nerve cells for the local processing of visual
information. This information is sent to the brain for decoding into a visual
image. The adjacent retinal pigment epithelium (RPE) supports many of the
retina's metabolic functions.  
  
The retina is susceptible to a variety of diseases, including age-related
macular degeneration (AMD), diabetic retinopathy (DR), retinitis pigmentosa
(RP) and other inherited retinal degenerations, uveitis, retinal detachment,
and eye cancers. Each of these can lead to visual loss or complete blindness.  
  
The leading cause of visual loss among elderly persons is AMD, which has an
increasingly important social and economic impact in the United States. As the
size of the elderly population increases in this country, AMD will become a
more prevalent cause of blindness than both DR and glaucoma combined.  
  
DR is also a major cause of blindness. In the proliferative stage of the
disease, newly formed, abnormal blood vessels can break through the retinal
surface and hemorrhage into the normally transparent, gelatin-like vitreous in
the middle of the eye. Scar tissue may subsequently form and pull the retina
away from the back of the eye, causing a retinal detachment to occur.  
  
Rare inherited retinal degenerations, typified by RP, result in the
destruction of photoreceptor cells and the RPE.  
  
Clinical evidence has shown that long-term use of chloroquine (CQ) and/or
hydroxychloroquine (HCQ) can lead to irreversible retinal toxicity. SCODI may
be indicated to provide monitoring of patients for the development of
retinopathy during long-term therapy.  
  
 **SCODI Techniques**  
  
There are several forms of SCODI tests that currently exist. SCODI testing
includes scanning laser polarimetry (SLP), optical coherence tomography (OCT),
and confocal scanning laser ophthalmoscopy (CSLO). These testing devices use
videographic digitized images to make quantitative topographic measurements of
the optic nerve head and surrounding retina. Although these techniques are
different, their objective is the same. These methods are described below:

  * **_Scanning Laser Polarimetry (SLP)_**  
The retinal nerve fiber layer (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, 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.  
  

  * **_Optical Coherence Tomography (OCT)_**  
OCT uses near-infrared light to provide direct cross-sectional measurement of
the retinal nerve fiber layer. The principals employed are similar to those
used in B-mode ultrasound except light, not sound, is used to produce the
3-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.  
  

  * **_Confocal Scanning Laser Ophthalmoscopy (CSLO)_**  
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 Tomograph is probably the most common example of this
technology.

**Covered Indications**

**Anterior segment SCODI** will be considered medically reasonable and
necessary for evaluation of specified forms of glaucoma and certain disorders
of the cornea, iris and ciliary body.

**Posterior segment SCODI** will be considered medically reasonable and
necessary under the following circumstances:

  1. For the diagnosis and management of a patient who has mild, moderate, severe, or indeterminate stage glaucoma or who is suspected of having glaucoma.
  2. Monitoring patients being treated with chloroquine (CQ) and/or hydroxychloroquine (HCQ) for the development of retinopathy.
  3. The evaluation and treatment of patients with conditions affecting the optic nerve (e.g., optic neuropathy) or retinal disease (e.g., macular degeneration, diabetic retinopathy) and in the evaluation and treatment of certain macular abnormalities (e.g., macular edema, atrophy associated with degenerative retinal diseases).

**Limitations**

The following are considered not medically reasonable and necessary:

  1. SCODI is usually not medically reasonable and necessary when performed to provide additional confirmatory information regarding a diagnosis which has already been determined. Documentation should support that the SCODI test result was used for establishing a diagnosis, establishing a baseline prior to treatment, or for monitoring purposes.
  2. Fundus photography and posterior segment SCODI performed on the same eye on the same day are generally mutually exclusive of one another ( _National Correct Coding Initiative [NCCI] Policy Manual for Medicare Services_ ). The provider is not precluded from performing both on the same eye on the same day when each service is necessary to evaluate and treat the patient. The medical record should clearly document the medical necessity of each service. Frequent reporting of these services together may trigger focused medical review.
  3. Screening (patient without signs or symptoms) for any condition is not medically reasonable and necessary.

**  
Place of Services (POS)  
  
** For additional information on services performed in an Independent
Diagnostic Testing Facility (IDTF), please refer to Local Coverage
Determination (LCD) L35448 Independent Diagnostic Testing Facility (IDTF).  
  
For frequency limitations, please refer to the Utilization Guidelines section
below.  
  
 **Notice:** Services performed for any given diagnosis must meet all of the
indications and limitations stated in this policy, the general requirements
for medical necessity as stated in CMS payment policy manuals, any and all
existing CMS national coverage determinations, and all Medicare payment rules.

Scanning computerized ophthalmic diagnostic imaging (SCODI) allows for the
early detection of glaucomatous damage to the nerve fiber layer or optic nerve
and has demonstrated clinical utility in facilitating earlier diagnosis and
treatment as well as monitoring for progression and response to treatment.
Evidence-based guidelines (2015 Academy of Ophthalmology [AAO] Preferred
Practice Pattern [PPP] on Primary Open-Angle Glaucoma and 2010 American
Optometric Association [AOA] Optometric Clinical Practice Guideline on Care of
the Patient with Open Angle Glaucoma) identify SCODI as one technique that may
be used to examine the optic nerve head (ONH) and/or retinal nerve fiber layer
(RNFL). SCODI is often used to provide quantitative information to supplement
the clinical exam of the optic nerve. SCODI is widely used in the posterior
segment, whereas in the anterior segment, the use is still limited.

The evidence-based guideline from the AAO (2015 AAO PPP on Primary Angle
Closure) indicates that anterior segment imaging should be considered when
angle anatomy is difficult to assess on gonioscopy. There is good evidence
demonstrating general agreement between findings on gonioscopy and anterior
segment imaging, including ultrasound biomicroscopy and anterior segment
optical coherence tomography (AS-OCT). However, AS-OCT is limited to
evaluating the iridocorneal angle. AS-OCT is one technology that may prove
useful in evaluating secondary causes of angle closure and elucidating plateau
iris.

SCODI is also a valuable tool for the evaluation of patients with retinal
disease, especially those with macular abnormalities. SCODI is often used in
conjunction with clinical examination of the eye. It is at times used as a
baseline and also used in monitoring for progression or response to treatment.
The clinical utility of OCT imaging in retinal conditions has been
demonstrated as providing an objective, accurate assessment of the amount and
location of retinal thickening. Evidence-based guidelines from the AAO (PPP
Diabetic Retinopathy [2016] and the PPP Idiopathic Macular Hole [2014, updated
2017]) support that in clinical practice, decisions are often based on OCT
findings.

Finally, Marmor et al (AAO Statement 2016) published recommendations on
screening patients who are being treated with Chloroquine and
Hydroxychloroquine.  A baseline test is performed and then ongoing monitoring
at regular intervals is recommended.  Marmor et al recommends beginning annual
screening after 5 years for patients on acceptable doses of chloroquine or
hydroxychloroquine and without any major risk factors.

Multiple sources of literature were submitted for consideration of posterior
SCODI for advanced (severe) stage glaucoma and anterior SCODI to examine the
structures of the anterior segment of the eye.

In an observational case study, Leite et al (2010) looked at 99 patients with
glaucomatous eyes and 47 control patients.  The severity of disease was graded
using the visual field index (VFI) from standard automated perimetry. The
authors looked to determine if disease severity had any impact on the
diagnostic accuracy of OCT. The average VFI for the glaucomatous eyes was
85.5% and for the control eyes was 99.4% indicating very minimal visual field
loss. The results show that for those with mild disease (VFI near 100%) the
sensitivity of OCT was 47% and the specificity was 95%.  For those patients
with a VFI of 70%, the sensitivity increased to 84% and the specificity was
95%.

Bowd et al (2017) published a study that looked to estimate the measurement
floors for spectral-domain optical coherence tomography (SD-OCT) measurements
(minimum rim width [MRW], ganglion cell-inner plexiform layer thickness [GC-
IPLT], and circumpapillary retinal nerve fiber layer thickness [cpRNFLT]) and
compared global change over time in advanced glaucoma eyes. The study included
a variability group of 41 eyes of 27 glaucoma patients with moderate to
advanced glaucoma to estimate the measurement floors and 87 eyes of 59
patients with advanced to severe glaucoma in a longitudinal group. Average
structural loss of MRW, macular GC-IPLT, and cpRNFLT in the variability group
eyes (over 5 weeks of follow- up) and the longitudinal group eyes (over 2
years of follow-up) was presented. The results indicated the mean percentage
of image area that did not reach the floor in the baseline images of eyes in
the longitudinal group (i.e., the image percentage that changed after 2 years
of follow-up) was 19% for MRW, 36% for GC-IPLT, and 14% for cpRNFLT,
indicating that GC-IPLT likely is the most robust measurement for assessing
localized change in eyes with advanced glaucoma eyes. Authors concluded that a
significant percentage of SD-OCT-measured retinal tissue is spared from the
measurement floor in advanced glaucoma eyes. In addition, progressive thinning
of the spared tissue is observable well into late-stage disease, particularly
when GC-IPLT is the structural parameter measured. These results indicate that
optical imaging, particularly SD-OCT imaging, has a place in detecting
structural change in eyes with advanced glaucoma.

Belghith et al (2016) did a study is to compare SD-OCT standard structural
measures MRW, ganglion cell-inner plexiform layer (GC-IPL), and cpRNFL and a
new three-dimensional (3D) volume optic nerve head (ONH) change detection
method for detecting change over time in severely advanced-glaucoma (open-
angle glaucoma [OAG]) patients. The study included three groups of
participants. The first group was composed of 35 eyes of 35 advanced-glaucoma
patients followed for an average of 3.5 years. The stable glaucoma group
consisted of 50 eyes from 27 early-, moderate-, and advanced-glaucoma patients
with five serial OCT exams imaged every week for 5 weeks. A third group of 46
eyes from 30 healthy subjects followed for an average of 2.8 years was used to
estimate the aging effects. Results suggest that even in very advanced
glaucoma, structural loss can be detected in some eyes using standard global
structural measures. Specifically, macular GC-IPL had the highest proportion
of eyes with detectable change (31%), followed by MRW (11%) and cpRNFL (4%).
In addition, the 3D whole-volume Bayesian-kernel detection scheme (BKDS)
change method, which does not require extensive retinal layer segmentation,
detected change in 37% of eyes. The authors concluded the results suggest that
even in very advanced disease, structural change can be detected, and that
monitoring macular GC-IPL and 3D whole-volume patients BKDS change shows
promise for identifying progression in advanced glaucoma. However, a larger
sample of advanced-glaucoma patients with longer follow-up is needed to
validate these findings.

In a retrospective case note review, Hau et al (2015) compared AS-OCT with
ultrasound B-scan (USB) in evaluating iris and iridociliary body lesions.
Patients with other anterior or posterior segment lesions or tumors were
excluded from this study. The study included 126 patients (126 eyes), the mean
age of the patient group was 57.8, who were imaged with both AS-OCT and USB
presenting to the same ocular oncology center over a 2 year period of time.
The three most common diagnoses were iris naevi, iris pigment epithelial
cysts, and iris melanoma. The aim of the study was to evaluate which imaging
modality (AS-OCT vs. USB) provided better visualization and characterization
of a large cohort of iris and iridociliary body lesions. High-frequency
ultrasound biomicroscopy (UBM) was not included in this study, but was
referenced as having some distinct advantages over USB and AS-OCT as well as
limitations on use. The results revealed that USB was better than AS-OCT in
visualizing all tumor margins, posterior tumor margin, and producing less
posterior shadowing. USB was slightly better for resolving the overall tumor
and posterior tumor surface, but AS-OCT was better for resolving the anterior
and lateral tumor surface. In total, AS-OCT was able to detect more lesions
than USB, especially in imaging iris lesions, but it was unable to detect any
of the ciliary body lesions.  The authors concluded that AS-OCT is superior to
USB for imaging small lesions pertaining to the anterior iris but USB is
better for imaging larger iris lesions with posterior or ciliary body
extension.

Janssens et al (2016) conducted a systematic review to determine how accurate
AS-OCT and UBM are in determining tumor margins and tumor depth of
conjunctival and corneal tumors and if either of these techniques can provide
additional information regarding the diagnosis. Fourteen sources were selected
to analyze corneal and conjunctival tumor thickness and internal
characteristics and extension in depth and size and shape measured by either
of these two noninvasive techniques, AS-OCT or UBM, or a combination of both.
The study designs included retrospective analysis, retrospective
interventional case series, retrospective non-interventional case series,
prospective studies, and unknown study designs. The number of patients in
articles using UBM (alone) in conjunctival and corneal tumors totaled 44, the
number of patients in articles using AS-OCT (alone) in conjunctival and
corneal tumors totaled 211 (212 eyes), and the number of patients in articles
using both UBM and AS-OCT in conjunctival and corneal tumors totaled 235 (238
tumors). The results show that both AS-OCT and UBM imaging techniques provide
useful information about the internal features, extension, size, and shape of
tumors. There is not enough evidence on the advantages and disadvantages of
AS-OCT and UBM in certain tumor types. The authors concluded that more
comparative studies are needed to investigate which imaging technique is most
suitable for a certain tumor type.

The clinical utility of SCODI has been established and validated in evidence-
based guidelines and literature for early detection of glaucomatous damage to
the retinal nerve fiber layer or optic disc, differentiation and diagnosis of
other disorders of the optic nerve as well as monitoring for progressive optic
neuropathy, monitoring retinal conditions, and drug-related ocular toxicity.

A number of studies have been published to evaluate the usefulness of
posterior OCT for individuals with advanced glaucomatous damage as well as the
potential applications of anterior segment OCT (AS-OCT and SD-OCT with
anterior segment imaging capabilities) to image and provide measurements of
anterior segment structures in a number of clinical situations. Overall, these
studies have small sample sizes, relatively limited follow-up, and no
documentation of improved health outcomes in the Medicare population. Some of
the studies have populations that would not be generalizable to the Medicare
population.