Aetna Optic Nerve & Retinal Imaging Coverage

Medically Necessary Indications

Covered when documenting optic nerve head and retina appearance for the following diagnoses/individuals:

Covered indications: Age-related macular degeneration; Cystoid macular edema following cataract surgery; Diabetic retinopathy; Ethambutol-induced optic neuropathy; Glaucoma; Glaucoma suspects; Macular edema; Macular hole; Non-arteritic anterior ischemic optic neuropathy; Posterior vitreous detachment; Pseudotumor cerebri; Screening and monitoring for chloroquine (Aralen), ethambutol (Myambutol), ezogabine (Potiga), hydroxychloroquine (Plaquenil), ponatinib (Iclusig), siponimod (Mayzent), and vigabatrin (Sabril) toxicity; Sudden onset vitreous hemorrhage; Vitreomacular traction and vitreomacular adhesion; Vogt-Koyanagi-Haradas (to quantify subretinal fluid and to follow individuals during treatment); and other diseases where the optic nerve head and retina have been affected.

List as provided in policy

Frequency Limitation

Coverage limitation for glaucoma imaging frequency:

Glaucoma imaging interval: Optic nerve imaging for glaucoma more frequently than once per year is considered not medically necessary.once per year

Repeated imaging not needed more frequently than annually due to slow progression of glaucoma.

Experimental or Investigational Indications

Experimental / Investigational — not covered

Experimental indications: Annual follow‑up of thyroid ophthalmopathy; cataracts; dry eye diseases; use of imaging solely to decide need for surgery; evaluation of neurodegeneration patterns in individuals with intracranial tumors; Parinaud oculoglandular syndrome (cat‑scratch disease); schizophrenia spectrum disorders; visual snow syndrome; imaging following intra‑ocular lens exchange after IOL dislocation; imaging of the retina as a biomarker for frontotemporal degeneration, multiple sclerosis, and optic neuritis; ocular histoplasmosis; posterior capsule opacification; routine screening of asymptomatic persons for glaucoma and other retinal diseases; screening/monitoring of persons on fingolimod; and patient‑initiated remote OCT image capture and transmission to a remote surveillance center.

Policy lists these as experimental/investigational.

General coverage interpretation

Coverage stance based on evidence summarized in this section:

Evidence summary: Imaging devices are accepted for documenting optic nerve head and retinal appearance and may replace drawings or fundus photographs; however, prospective longitudinal evidence that imaging improves clinical outcomes for glaucoma screening/early detection is limited. For certain retinal indications (for example, quantification of macular thickness in diabetic macular edema and assessment of macular hole), laser scanning imaging and OCT have level I evidence supporting diagnostic accuracy and utility.

See related device‑specific discussion in policy background

HCQ/CQ Retinopathy Screening

Screening for hydroxychloroquine/chloroquine retinopathy:

HCQ/CQ screening: Baseline ophthalmic examination is recommended prior to initiation of chloroquine or hydroxychloroquine therapy to document the macula and serve as a reference. Annual screening should begin after 5 years of exposure (earlier if there are unusual risk factors). Screening should include 10‑2 automated visual fields plus at least one objective test where available (mfERG, spectral‑domain OCT, or fundus autofluorescence); mfERG may substitute for visual fields. Dose considerations: routine 400 mg HCQ daily is generally acceptable except for short‑stature individuals where ideal body weight dosing is recommended.time‑based (>=5 years) and test modality

Guidance aligned with AAO and summarized evidence

OCT summary metrics caution

Detecting progression in advanced glaucoma using OCT summary measures:

OCT summary metric limitations: Global OCT summary metrics (e.g., GcRNFL, GGCLP) can be substantially affected by segmentation, alignment, and centering errors; inspection of B‑scans and thickness maps is important, and summary metrics alone have limited utility for progression detection in advanced glaucoma.N/A

Segmentation errors were a major factor in many examined cases.

OCT in MS

OCT as a biomarker in multiple sclerosis:

MS monitoring with OCT: Longitudinal ganglion cell + inner plexiform layer (GCIP) atrophy rates correlate with whole‑brain and gray matter atrophy, particularly in progressive MS. OCT can be used for clinical monitoring and as an outcome measure in trials, but findings require replication in larger, more homogeneous cohorts and consideration of optic neuritis history and treatment heterogeneity.longitudinal correlation metrics

Median follow‑up in cited study ~46 months; limitations include cohort heterogeneity and treatment variability.

Supported clinical indications

Clinical situations where OCT/OCTA or related imaging are supported by the evidence summarized here:

Supported uses: Use of OCT/OCTA/FA/ICGA is supported for: diagnosis and monitoring of Vogt‑Koyanagi‑Harada disease (detection of choroidal thickness changes, sub‑retinal membranous structures, RPE folds, and large retinal detachments); detection of prior unilateral optic neuritis using inter‑eye RNFL and GCIPL thinning thresholds; adjunctive screening and monitoring for ethambutol‑induced optic neuropathy (in combination with visual fields and clinical exam); assessment of retinal and RNFL changes related to intracranial tumors compressing the visual pathway; and imaging of neuroretinitis/macular stars in Bartonella henselae infection when clinically indicated.

Derived from observational studies and society statements cited in the policy.

Imaging recommendations and clinical monitoring contexts

Imaging and monitoring are suggested/recommended in the cited literature under specific clinical circumstances:

Hydroxychloroquine monitoring: Baseline assessment within 1 year of starting long‑term antimalarial therapy is advised. Frequency of follow‑up can be individualized; AAO suggests deferring follow‑up until 5 years for low‑risk patients, but annual exams are often preferred. Use sensitive modalities (mfERG, SD‑OCT, FAF) to detect early toxicity and discontinue antimalarials immediately if retinopathy is suspected.daily dose >5 mg/kg real body weight, duration >5 years, renal disease, tamoxifen use

References include AAO guidance and UpToDate summaries.

Ethambutol monitoring: Baseline visual acuity and color testing are recommended; perform periodic monitoring and prompt ophthalmology referral for visual changes. OCT and pattern VEP may detect early or subclinical changes; studies report subclinical findings in some patients and reversibility after drug cessation in many cases. Formal visual field testing should be included in screening protocols.dose ~15 mg/kg; monitoring during therapy and up to 12 months after cessation per some studies

References: AAO guidance and observational studies.

Use of ONSD to assess intracranial hypertension

Coverage stance and contextual guidance from the evidence presented:

ONSD as adjunctive test: Optic nerve sheath diameter (ONSD) measurement by ultrasound or CT may be considered an adjunctive assessment for suspected elevated intracranial pressure when invasive ICP monitoring is not indicated or available; it is not a replacement for invasive monitoring where feasible.see meta‑analysis examples (pooled sensitivity ~0.9, specificity ~0.85; AUC ~0.93)

Interrater variability and lack of recommendation to use ONSD as sole diagnostic modality are cautioned.

Evaluation and management of Visual Snow Syndrome

Clinical evaluation and diagnostic considerations for Visual Snow Syndrome:

VSS evaluation: Neuro‑ophthalmologic assessment should exclude retinal and neurologic diseases when visual snow syndrome is suspected. Ophthalmic testing including BCVA, visual fields, pupillary responses, contrast sensitivity, electrophysiology (full‑field and mf‑ERG), and OCT are typically normal in VSS; treatment evidence is limited and primarily anecdotal or Class IV, with lamotrigine showing the strongest limited evidence in small series.n/a

Retrospective cohorts show mostly normal ophthalmic findings; exclude other causes prior to attributing symptoms to VSS.

Patient-initiated and portable OCT

Emerging applications and current evidence for mobile/hand-held OCT:

mobile/hand-held OCT use: Mobile WebUI and hand‑held OCT systems have demonstrated technical feasibility for posterior segment imaging, remote interactivity, and point‑of‑care/home monitoring in small feasibility studies, but clinical outcome benefit and diagnostic equivalence to standard clinic systems have not been established; well‑designed studies are needed before routine adoption.n/a

Patient‑initiated remote OCT is considered experimental per policy; operational considerations include documenting device, connection, and supervision.

ONSD to predict neurologic outcomes post-cardiac arrest

Use of ONSD measurements for predicting neurologic outcomes after cardiac arrest:

ONSD prognostication: ONSD has been studied as a predictor of poor neurologic outcome after return of spontaneous circulation; meta‑analyses and single‑center studies report variable sensitivity and generally high specificity. Example thresholds reported include 4.9 mm at 24 hours (sensitivity 83.3%, specificity 94.4% in one study) and percent change thresholds (>27.2% ONSD change associated with 100% specificity in a retrospective CT study), but heterogeneity, timing, and methodological limitations limit definitive prognostic use. ONSD should not be used as the sole basis for withdrawal of care.examples: 4.9 mm (single study), >27.2% change (single study)

Authors call for larger prospective studies and caution in clinical application.

Evidence summaries by indication

Summarized clinical findings and evidentiary conclusions present in this section:

ONSD for post-cardiac arrest prognostication: A retrospective single‑center CT study (n=96) found greater absolute and percent ONSD change associated with poor neurologic outcome; AUC was 0.64 and a >27.2% ONSD change had 100% specificity and PPV for poor outcome; authors recommend larger prospective studies due to limitations.rate of ONSD change >27.2% associated with 100% specificity/PPV

Single‑center retrospective design and outcome at discharge limit generalizability.

OCTA in diabetic retinopathy: Multiple observational studies report OCTA‑detected microvascular abnormalities (enlarged FAZ, reduced vessel density) in diabetic patients, including those without clinical diabetic retinopathy; OCTA may detect early retinal ischemia and has promise as a quantitative biomarker, but longitudinal predictive validity is not yet established.

Heterogeneity of devices and study designs limits generalizability.

SD‑OCT and MS/optic neuritis: Inter‑eye differences in GCIPL and pRNFL measured by SD‑OCT, particularly combined with visual function tests, improve discrimination for prior unilateral optic neuritis and MS history in cross‑sectional large multisite data; longitudinal predictive value requires further study.

Routine population screening of asymptomatic persons for glaucoma and other retinal diseases is listed as experimental/investigational and not covered in this policy. The CPB explicitly identifies routine screening of asymptomatic individuals among procedures considered investigational and cites several ICD‑10 code groups that are not covered for the listed indications (examples include codes for cat‑scratch disease, intracranial tumors, thyroid ophthalmopathy following orbital decompression, schizophrenia, frontotemporal dementia, dry eye, cataracts, and visual snow syndrome).

A baseline imaging study is, however, considered medically necessary prior to initiation of certain medications (chloroquine, hydroxychloroquine, vigabatrin) and targeted monitoring and diagnostic uses for many listed disease states remain covered when clinical indications are met; the exclusion applies specifically to routine, asymptomatic population screening rather than to targeted, diagnostic, or medication‑monitoring imaging.

The policy states that use of retinal nerve fiber layer analysis (RNFLA) or other optic nerve imaging devices solely for glaucoma screening or population screening is not supported by the available longitudinal evidence. Technology assessments cited in the CPB found that most studies are cross‑sectional and that prospective longitudinal data demonstrating improved clinical outcomes from screening with RNFLA are lacking.

Because RNFLA abnormalities often do not predict which patients will develop visual field loss, the policy cautions against relying on optic nerve head imaging alone to decide initiation of glaucoma treatment or to change management without clinical correlation and longitudinal outcome evidence.

No additional explicit coverage criteria are provided in this excerpt for this topic.

The policy does not state that OCT or OCTA can replace formal visual field testing for ethambutol toxicity screening. For patients on ethambutol the CPB emphasizes regular ophthalmologic screening that includes formal visual field testing; OCT and visual evoked potentials may be helpful adjuncts but are not described as substitutes for established screening modalities.

Evaluation of Visual Snow Syndrome (VSS) typically demonstrates normal routine vision testing and normal brain imaging; the policy notes that fundus photography and posterior segment scanning ophthalmic imaging are not described as diagnostic tools for VSS in the cited sources. Neuro‑ophthalmologic assessment should focus on excluding retinal and neurologic diseases, and available ophthalmic tests (including OCT) are usually normal in VSS.

Ultrasound measurement of optic nerve sheath diameter (ONSD) may be useful as an adjunct to evaluate suspected raised intracranial pressure, but the policy cautions that ONSD should not be relied upon as the sole imaging modality for head trauma diagnosis. The CPB references inter‑rater variability in sonographic ONSD measures and states that ONSD is not a replacement for invasive ICP monitoring when invasive monitoring is feasible and indicated.

An UpToDate review on Graves’ orbitopathy (cited in the policy) does not mention OCT as a management option; the CPB therefore indicates that OCT/OCTA is not established as a routine, guideline‑endorsed management tool for Graves’ orbitopathy and that use for this indication remains observational in the literature.

The policy specifies that optic nerve imaging for glaucoma performed more frequently than once per year is considered not medically necessary. Because glaucoma typically progresses slowly, repeated optic nerve head imaging is generally not required more often than annual intervals.

The CPB indicates that routine use of RNFLA to make treatment decisions—such as initiating early glaucoma therapy or changing regimens—is not supported by the evidence. Technology assessments and longitudinal data (including a subset analysis from the Ocular Hypertension Treatment Study) showed a low positive predictive value for RNFLA in predicting conversion to glaucoma, and thus RNFLA alone should not drive treatment initiation or escalation without clinical correlation.

Although not framed as an explicit 'not medically necessary' rule in the excerpt, the policy highlights limitations of global OCT summary metrics in advanced glaucoma. Segmentation, alignment, and centering errors can substantially affect summary measures (e.g., GcRNFL, GGCLP), so caution is advised when interpreting summary OCT metrics alone for detecting progression in advanced disease.

Authors cited in the CPB note that evidence is currently insufficient to endorse routine OCT as a standalone diagnostic tool for optic neuritis and subclinical optic neuropathy. Larger, disease‑specific longitudinal studies are needed before routine, unaccompanied use of OCT for these diagnoses can be recommended.

ONSD measurements have been investigated for prediction of intracranial hypertension and for prognostication after cardiac arrest, but the policy reiterates that ONSD is not a replacement for invasive intracranial pressure monitoring when invasive methods are feasible and indicated. Meta‑analyses show good pooled sensitivity and specificity, yet variability and limitations mean ONSD should be used as an adjunctive test only.

Coding

Covered CPT Codes (if selection criteria met)CPTCovered

92133	Scanning computerized ophthalmic diagnostic imaging, posterior segment, with interpretation and report, unilateral or bilateral; optic nerve.
92134	Scanning computerized ophthalmic diagnostic imaging, posterior segment, with interpretation and report, unilateral or bilateral; retina.

CPT/HCPCS Codes Not Covered for Indications ListedCPTNot Covered

0469T	Retinal polarization scan, ocular screening with on-site automated results, bilateral.
0604T	Optical coherence tomography (OCT) of retina, remote, patient-initiated image capture and transmission to a remote surveillance center unilateral or bilateral; initial device provision, set-up and patient education on use of equipment.
0605T	Optical coherence tomography (OCT) of retina, remote, patient-initiated image capture and transmission to a remote surveillance center unilateral or bilateral; remote surveillance center technical support, data analyses and reports, with a minimum of 8 daily recordings, each 30 days.
0606T	Optical coherence tomography (OCT) of retina, remote, patient-initiated image capture and transmission to a remote surveillance center unilateral or bilateral; review, interpretation and report by the prescribing physician or other qualified health care professional of remote surveillance center data analyses, each 30 days.

ICD-10 Codes Covered / Not Covered (mixed listing)ICD-10

B39.4	Infection by Histoplasma capsulati, unspecified [retinitis caused by histoplasma capsulati] (H32 also required).
E08.311 - E08.3599	Diabetes mellitus due to underlying condition with ophthalmic complications.
G35	Multiple sclerosis [screening and monitoring for siponimod (Mayzent) toxicity].
G40.201 - G40.219	Localization-related (focal)(partial) symptomatic epilepsy and epileptic syndromes... [screening for vigabatrin (Sabril) toxicity].
H40.001 - H40.9	Glaucoma.
H43.10 - H43.13	Vitreous hemorrhage.
H43.811 - H43.819	Vitreous degeneration [posterior vitreal detachment] (not covered for vitreous degeneration).
H46.00 - H47.399	Disorders of optic nerve.
Z13.5	Encounter for screening for eye and ear disorders.

ICD-10 Codes Not Covered for Indications ListedICD-10Not Covered

A28.1	Cat-scratch disease.
C71.0 - C71.9	Malignant neoplasm of brain [intracranial tumors].
E05.00 - E05.01	Thyrotoxicosis with diffuse goiter [thyroid ophthalmopathy after orbital decompression].
F20.00 - F20.9	Schizophrenia.
G31.01 - G31.09	Frontotemporal dementia.
H04.121 - H04.129	Dry eye syndrome.
H25.011 - H28	Cataracts.
H53.8	Other visual disturbances [visual snow syndrome].

Referenced procedures and tests (no billing codes provided)mixed

none listed

No CPT/HCPCS/ICD codes are provided in this excerpt.

Baseline screening for specific medications

Baseline exam before initiationA baseline optic nerve and retinal imaging study is considered medically necessary prior to starting chloroquine, hydroxychloroquine, or vigabatrin therapy.

Timing for routine screeningAnnual screening should begin after 5 years of use (or sooner if there are unusual risk factors).

Tests recommended for HCQ/CQ screeningUse 10-2 automated visual fields plus at least one objective test where available (mfERG, SD-OCT, or FAF).

Purpose of baseline studyServe as a reference point and to rule out pre-existing maculopathy which may contraindicate therapy.

HCQ toxicity risk and TMH cutoff

HCQ toxicity risk timingRisk of hydroxychloroquine toxicity increases sharply toward ~1% after 5–7 years of use or a cumulative dose of ~1000 g.

Dose considerationsMost patients receive 400 mg HCQ daily (consider ideal body weight dosing for short-stature individuals to avoid overdosage).

TMH OCT cutoffOCT lower tear meniscus height (TMH) cutoff <0.30 mm yielded sensitivity 67% and specificity 81% for dry eye in a prospective study.

Screening modalities sensitivityNewer objective tests (mfERG, SD-OCT, FAF) can be more sensitive than visual fields for early HCQ toxicity detection.

Inter-eye OCT thinning thresholds

RNFL inter-eye difference thresholdRetinal nerve fiber layer (RNFL) thinning considered significant if inter-eye difference ≥ 9 µm.

GCIPL inter-eye difference thresholdGanglion cell–inner plexiform layer (GCIPL) thinning considered significant if inter-eye difference ≥ 6 µm.

Use caseInter-eye difference thresholds used to detect prior unilateral optic neuritis; GCIPL showed higher sensitivity than RNFL in cited study.

Retinal detachment height considered notable in VKH

Notable retinal detachment height in VKHRetinal detachment height > 450 μm was reported as a common and notable OCT finding in acute VKH (Liu et al.).

Associated OCT featuresOther frequent OCT features in VKH included hyper-reflective dots, sub-retinal membranous structures, and RPE folds.

Diagnostic performanceHigh retinal detachment and sub-retinal membranous structures had good sensitivity/specificity for acute VKH in the referenced cohort.

ONSD threshold (Tayal study)

Tayal study ONSD cutoffAn ONSD value of 5.205 mm was 95.8% sensitive and 80.4% specific for detecting raised intracranial pressure in the referenced prospective study.

Correlation with ICPSonographic ONSD measurements showed a strong correlation with invasive ICP measurements (Spearman correlation coefficient reported at 0.82 in a cited study).

Guideline contextACEP guidelines note ONSD as a potential sonographic reflection of intracranial disease but emphasize technique and context when used clinically.

ONSD threshold for poor neurologic outcome (single study at 24 hours)

ONSD threshold for poor neurologic outcomeAn ONSD > 4.9 mm at 24 hours had sensitivity 83.3% and specificity 94.4% for predicting poor neurologic outcome in a cited single-center study.

Timing and variabilityPredictive performance varied by timing of measurement and study design; authors call for larger prospective studies.

Meta-analytic contextMeta-analyses report variable pooled sensitivity/specificity for ONSD in prognostication after cardiac arrest; caution advised in interpretation.

Provider Actions and Operational Guidance

Billing Rule

Coverage for standard OCT/scanning imaging codes

CPT codes 92133 and 92134 (scanning computerized ophthalmic diagnostic imaging, posterior segment, with interpretation and report) are covered when the policy's clinical selection criteria are met. Other listed CPT/HCPCS codes for patient‑initiated remote OCT (0604T–0606T) and retinal polarization screening (0469T) are not covered for the indications in this policy.

Covered CPT: 92133, 92134
Not covered CPT: 0469T, 0604T, 0605T, 0606T

Prior Authorization

Ophthalmology monitoring for FGFR/targeted therapies

For systemic cancer therapies associated with serous retinopathy (e.g., FGFR inhibitors such as erdafitinib and agents with similar risk profiles), ophthalmology monitoring is recommended. Follow prescribing information and specialty guidance: baseline ophthalmologic exam, monthly exams (visual acuity, slit lamp, fundus exam, and OCT) during the first 4 months, then every 3 months thereafter, with urgent reevaluation for visual symptoms and dose modification/withholding per drug guidance.

Example agents: erdafitinib, ponatinib, dovitinib (FGFR inhibitors)
Monitoring cadence: baseline, monthly x4, then q3 months; urgent evaluation for new symptoms
Action: withhold drug for serous retinal toxicity and discontinue if not resolved within recommended interval

Prior Authorization

Prior authorization for mobile/hand-held OCT (operational note)

Emerging mobile and hand‑held OCT technologies show feasibility for point‑of‑care and remote use, but clinical utility and operational workflows remain evolving. If mobile/hand‑held OCT is used, document the device type, operator, imaging protocol, and whether remote specialist guidance was provided. Prior authorization may be appropriate for novel device deployments per plan operational requirements.

Document device model, probe type (hand‑held vs fixed), and connection type (wireless/VPN/cellular)
Document whether remote guidance or real‑time specialist control was used
Operational note: payer may require prior authorization for nonstandard device use

Denial Risk

Remote patient-initiated OCT not supported

Patient‑initiated image capture and transmission to a remote surveillance center via OCT (the 0604T–0606T remote OCT service paradigm) is considered experimental/investigational and is not supported for coverage in this policy.

Remote patient‑initiated OCT described by CPT 0604T–0606T — experimental/investigational; not covered

Note

Evidence insufficiency risk

There is limited prospective evidence that optic nerve head imaging devices (including some RNFL analysis technologies) improve clinical outcomes when used for glaucoma screening or as a standalone diagnostic test; providers should use imaging as an adjunct to standard examination methods and be aware of evidence limitations.

Imaging is an adjunct — do not replace ophthalmoscopy, tonometry, perimetry, and gonioscopy
Limited evidence for standalone screening utility; prospective outcome data lacking

Documentation Required

Document diagnosis and indications

Document the clinical diagnosis and specific indication for imaging in the medical record. Imaging requests should be supported by findings or clinical rationale that align with the policy's list of medically necessary indications (e.g., AMD, diabetic retinopathy, macular edema, glaucoma, drug toxicity screening).

Record diagnosis from policy list (e.g., AMD, diabetic retinopathy, glaucoma, ethambutol/HCQ/vigabatrin/ponatinib/siponimod toxicity screening)
Include clinical findings prompting imaging (symptoms, exam abnormalities)

Documentation Required

Clinical indication and frequency documentation

Document clinical rationale and intended frequency for imaging (e.g., baseline and interval monitoring for drug toxicity, annual imaging for glaucoma surveillance unless clinically indicated more often). For drug toxicity screening, document dosing, weight/height, renal function, and cumulative exposure when relevant.

Baseline exam prior to HCQ/CQ or vigabatrin initiation; annual screening after 5 years (or sooner with risk factors) for HCQ/CQ
For ethambutol: baseline visual acuity and color testing; routine screening frequency individualized and document dosing and renal status

Documentation Required

Imaging documentation for diagnosis and monitoring

When imaging is used for diagnosis or monitoring, include the imaging modality, date, key findings, comparison to prior studies, and interpretation in the clinical record to support medical necessity and continuity of care.

Report modality (OCT, OCTA, FA, ICGA), measured parameters (e.g., RNFL thickness, macular thickness, vessel density) and comparison to prior values
Attach images or ensure availability in chart when possible

Documentation Required

Required documentation for drug toxicity monitoring

For monitoring of drug‑related ocular toxicity (eg, hydroxychloroquine, chloroquine, ethambutol, vigabatrin, ponatinib), document baseline exam results, dosing (daily dose, weight/height), renal function, cumulative exposure, and any objective ancillary tests used (OCT, mfERG, FAF, visual fields). Failure to document dosing and patient metrics may lead to denial of medical necessity.

Baseline fundus exam and objective tests before starting implicated drugs
Document daily dose, height, weight, renal status, cumulative dose, and dates of follow‑up testing

Documentation Required

Documentation for VSS evaluation

When evaluating Visual Snow Syndrome (VSS), document exclusion of retinal and neurologic causes, results of ophthalmologic testing (visual acuity, visual fields, pupillary reflex, contrast sensitivity, ERG/mfERG, OCT), and rationale for attributing symptoms to VSS.

Record normal retinal electrophysiology and imaging when VSS is diagnosed
Document trial of therapies if used (eg, lamotrigine) and response

Documentation Required

Documentation for remote/mobile OCT

For remote or mobile OCT studies, document the device and method (hand‑held vs table‑top), connection type (wireless, VPN, cellular), whether the acquisition was patient‑initiated or provider‑assisted, and whether a remote specialist provided real‑time or asynchronous review. If data were transmitted to a remote surveillance center, note that such workflows are considered investigational.

Document connection type and latency considerations when applicable
If remote surveillance center involved, include details of data analyses and reporting cadence

Documentation Required

Documentation for ONSD measurement

When optic nerve sheath diameter (ONSD) measurement is performed (US or CT) as an adjunct for suspected elevated intracranial pressure or prognostication after cardiac arrest, document the imaging modality, measurement technique, measured values, reference cutoffs, and whether invasive ICP monitoring was available.

Record measurement technique, operator, side(s), measured ONSD (mm) and comparison to prior studies
For prognosis after cardiac arrest, report pre/post arrest ONSD values and percent change when available

Note

Providers are responsible for medical advice and documentation

Providers are responsible for selecting appropriate imaging modalities and for medical decisions regarding patient care; Clinical Policy Bulletins are administrative guides and do not guarantee coverage. Treating providers must ensure documentation supports medical necessity.

Clinical Policy Bulletins do not constitute coverage guarantees
Providers must document clinical rationale to support imaging requests

Note

Use imaging as adjunct to standard exam; stepwise evaluation preference

Use imaging as an adjunct to, not a replacement for, the standard ophthalmologic examination (ophthalmoscopy, tonometry, perimetry, gonioscopy). Stepwise evaluation is preferred: start with standard clinical exam and use imaging when indicated to clarify or quantify pathology or to monitor response to therapy.

Perform comprehensive ophthalmologic exam prior to advanced imaging when feasible
Reserve OCT/OCTA/FA/ICGA to answer specific clinical questions or for monitoring documented pathology

Step Therapy

Therapeutic sequencing for VSS and stepwise monitoring expectation

Therapeutic sequencing and stepwise monitoring expectations: for Visual Snow Syndrome, limited evidence supports lamotrigine as the pharmacologic option with the strongest (but still limited) evidence before considering other agents off‑label. For optic neuropathies and glaucoma, correlate OCT RNFL thickness with visual field testing and tailor monitoring intervals accordingly; routine OCT more frequently than once yearly for glaucoma is generally not medically necessary.

VSS pharmacologic sequencing: consider lamotrigine before other agents (limited evidence)
Glaucoma imaging: OCT more frequently than once/year generally not medically necessary unless clinically justified

Denial Risk

Guideline non-endorsement risk

Guideline non-endorsement risk: absence of OCT/OCTA recommendation in major resources for certain indications (eg, Graves' orbitopathy per UpToDate) may reflect limited evidence for routine use; document clinical justification when using OCT/OCTA outside guideline‑endorsed indications.

UpToDate (Davies & Burch, 2023) does not list OCT as routine management for Graves' orbitopathy
When using OCT for non‑endorsed indications, provide explicit rationale in the record

Definitions

Confocal laser scanning ophthalmoscopy (SLO)

DefinitionConfocal laser scanning ophthalmoscopy (SLO) is stereoscopic digitized imaging using confocal laser scanning microscopy to make quantitative topographic measurements of the optic nerve head and surrounding retina.

Also calledAlso referred to as scanning laser ophthalmoscopy, confocal scanning laser topography, and confocal laser scanning tomography.

Device examplesExamples include Heidelberg Retina Tomograph (HRT), TopSS Topographic Scanning System, and Zeiss confocal laser scanning ophthalmoscope.

Nerve fiber layer testing / Laser scanning polarimetry (GDx)

Technique descriptionLaser scanning polarimetry measures change in the linear polarization (retardation) of light to estimate retinal nerve fiber layer thickness compared to normative databases (e.g., GDx system).

DevicesGDx Nerve Fiber Analysis System is an example combining confocal scanning laser ophthalmoscope with a polarimeter.

Clinical applicationUsed to assess RNFL thinning associated with glaucomatous damage and to compare results with normative values.

Optical coherence tomography (OCT)

ModalityOptical coherence tomography (OCT) is a noninvasive, transpupillary imaging technique using near-infrared light to produce high-resolution cross-sectional (B-scan) images of retinal structures.

OutputProvides quantitative measures including peripapillary RNFL thickness and macular layer thickness and generates thickness maps and B-scans.

UsesUsed for screening, diagnosis, and management of glaucoma and other retinal diseases, and as an adjunct to clinical examination.

Stereophotogrammetry

MethodStereophotogrammetry measures optic disc dimensions in three-dimensional space using paired stereophotographs and stereoanalysis for longitudinal documentation.

PurposeUsed to document optic nerve head morphology and follow glaucomatous change over time as an alternative to drawings or single photos.

ExamplesSystems include Glaucoma-Scope and stereoplotters with digital processing of scanned images.

Optical coherence tomography (OCT)

DefinitionOCT is a noninvasive imaging modality using reflected light to create high-resolution cross-sectional images of the retina and vitreoretinal interface and to provide quantitative peripapillary RNFL thickness measurements.

AnalogyOCT is analogous to ultrasound A-scan but uses low-coherence light interference to generate B-scan images and maps.

Clinical roleProvides objective structural data used in diagnosis and monitoring of macular and optic nerve diseases.

Confocal scanning laser ophthalmoscopy (CSLO) / Scanning laser polarimetry (SLP)

Technique groupConfocal scanning laser ophthalmoscopy (CSLO) and scanning laser polarimetry (SLP) are laser-based imaging techniques that provide quantitative measurements of the optic nerve head and RNFL (examples: HRT, GDx).

Measurement typesThese devices can provide topographic maps, RNFL thickness estimates, and compare measurements to normative databases.

Clinical contextUsed as alternatives or adjuncts to ophthalmoscopy and stereophotography in glaucoma and other optic nerve conditions.

RNFLA (retinal nerve fiber layer analysis)

DefinitionRNFLA refers to computer-based or device-derived analyses of retinal nerve fiber layer measurements intended to detect glaucomatous changes.

LimitationsRNFLA and summary metrics can be affected by segmentation, alignment, and centering errors; image inspection is important for interpretation.

RoleUsed to document optic nerve morphology and to assist in monitoring but should be interpreted alongside clinical findings and visual fields.

GcRNFL / GGCLP

Metrics definedGcRNFL = global circum-papillary retinal nerve fiber layer thickness; GGCLP = ganglion cell plus inner plexiform layer thickness measured from OCT circle and cube scans.

CaveatGlobal summary metrics may be unreliable for detecting progression in advanced glaucoma due to segmentation and other errors.

UseThickness maps and B-scan inspection are clinically useful complements to summary metrics.

Tear meniscus height (TMH)

DefinitionTear meniscus height (TMH) is the OCT measurement of the height of the tear meniscus used in diagnosing dry eye disease; lower TMH values correlate with dry eye.

Cutoff exampleIn a cited study, an OCT lower TMH cutoff <0.30 mm had sensitivity 67% and specificity 81% for dry eye diagnosis.

Clinical applicationTMH measurement by OCT can complement slit-lamp and other tear function tests in dry eye evaluation.

Choroidal tomographic morphology types (per Lee et al)

Choroidal morphology typesChoroidal tomographic morphology per Lee et al includes Standard (S), Dilated outer layer/attenuated inner layer (DA), Darkened (D), Marbled (M), and Pauci-vascular (PV).

Use in diseaseThese morphologic types help discriminate conditions like CSCR, PCV, and VKH based on EDI-OCT findings.

ExamplesVKH showed higher frequency of 'Darkened' type and convolution/scleral invisibility in the cited cohort.

Inter-eye difference thresholds for optic neuritis detection

Inter-eye difference thresholdsSignificant thinning consistent with prior optic neuritis: RNFL inter-eye difference ≥ 9 µm or GCIPL inter-eye difference ≥ 6 µm (Xu et al.).

Diagnostic sensitivityGCIPL inter-eye threshold was more sensitive (96%) than RNFL threshold (73%) for detecting prior optic neuritis in the cited study.

ApplicationThese thresholds support use of inter-eye OCT comparison in unilateral optic neuritis evaluation.

OCT / SD-OCT

OCT / SD-OCT definitionOptical coherence tomography (OCT), including spectral-domain OCT (SD-OCT), is a high-resolution noninvasive retinal imaging modality used to measure RNFL, macular thickness, and ganglion cell complex parameters.

Clinical roleSD-OCT provides detailed structural retinal imaging useful across many optic nerve and retinal conditions.

VariantsEnhanced depth imaging (EDI) and swept-source OCT are additional OCT techniques referenced in the literature.

Sub-clinical toxicity (ethambutol)

Sub-clinical toxicity conceptSub-clinical ethambutol toxicity refers to RNFL thickness change, VFI decrease, or visual field pattern defects detectable by testing without clinical visual symptoms.

Reported ratesSome studies reported sub-clinical changes in approximately 13–19% of eyes on ethambutol in cited cohorts.

ReversibilityMany sub-clinical changes reversed after cessation of ethambutol in longitudinal observations.

Visual Snow Syndrome (VSS)

VSS definitionVisual Snow Syndrome (VSS) is a disorder of central visual processing producing constant bilateral whole-field flickering or pixelation, often with additional visual and non-visual symptoms.

Evaluation notesOphthalmologic testing and brain imaging are typically normal; diagnosis requires exclusion of retinal or neurologic disease.

Treatment evidenceTherapeutic evidence is limited; lamotrigine showed modest response in small series.

Optic Nerve Sheath Diameter (ONSD)

ONSD definitionOptic nerve sheath diameter (ONSD) is the sonographic or CT measurement of the diameter of the optic nerve sheath posterior to the globe used as a noninvasive estimate correlated with intracranial pressure.

ModalitiesONSD can be measured by bedside ultrasound or on brain CT as an adjunctive estimate of raised ICP.

LimitationsInterrater variability and timing affect accuracy; ONSD should not replace invasive ICP monitoring where indicated.

Patient-initiated/mobile OCT

Patient-initiated/mobile OCT definitionPatient-initiated/mobile OCT refers to hand-held or mobile-controlled OCT systems, potentially with Web-based user interfaces enabling remote control and specialist interactivity for image capture.

Feasibility dataWebUI-controlled hand-held OCT captured posterior eye images in 20 subjects with low added latency; remote interactivity was demonstrated in feasibility studies.

Coverage stanceUse of patient-initiated remote OCT image capture and transmission is considered experimental/investigational in the policy context.

OCTA

OCTA definitionOptical coherence tomography angiography (OCTA) is a non-invasive technique that visualizes retinal blood flow by detecting motion contrast of moving blood cells, enabling layer-specific capillary plexus assessment.

Quantitative metricsOCTA provides quantitative perfusion metrics such as perfusion density and vessel density and can detect foveal avascular zone enlargement and capillary non-perfusion in diabetes.

Clinical potentialOCTA shows promise as a biomarker in vascular retinal disease but longitudinal predictive validity requires further study.

Perfusion density (PD)

Perfusion density (PD)Perfusion density is a quantitative OCTA metric representing the proportion of area occupied by blood flow signal within a retinal or peripapillary region.

Use in NAIONReduced PD in radial peripapillary capillaries and macular capillary plexuses has been reported in NAION affected and fellow eyes versus controls in meta-analysis data.

Interpretation caveatDevice- and study-specific heterogeneity limits generalizability; longitudinal predictive value remains to be established.

pRNFL

pRNFL definitionPeripapillary retinal nerve fiber layer (pRNFL) is the thickness measure around the optic nerve head commonly quantified by OCT.

Clinical relevancepRNFL thinning has been reported in conditions such as glaucoma, optic neuritis, NAION, and schizophrenia spectrum disorders in meta-analyses.

Measurement rolepRNFL is used as a structural biomarker in neuro-ophthalmic and neurodegenerative disease research and monitoring.

GCL-IPL

GCL-IPL definitionGanglion cell layer–inner plexiform layer complex (GCL-IPL) refers to macular inner retinal layers measured by OCT used to assess ganglion cell integrity.

SensitivityGCL-IPL thinning may be more sensitive than RNFL for detecting prior optic neuritis and other neurodegenerative retinal changes.

Research findingsMeta-analyses show significant GCL-IPL thinning in schizophrenia spectrum disorders and other conditions compared to controls.

Optical coherence tomography (OCT) and related imaging

OCT and related imaging summaryOptical coherence tomography and related imaging modalities (spectral-domain, swept-source, enhanced-depth imaging) provide high-resolution structural and quantitative measures for diagnosis and monitoring of optic nerve and retinal pathology.

Role in practiceThese imaging methods are accepted tools to document optic nerve head and retinal appearance and to supplement clinical examination, but longitudinal outcome data are limited in some screening contexts.

Device clearanceMany of these devices were cleared by the FDA via 510(k) submission based on substantial equivalence rather than PMA-level evidence.

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Optic Nerve and Retinal Imaging Methods

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