Medicare Claims at a Glance

Medicare Claims at a Glance
Medicare Part B Fee for Service Claims
Data type 100% Medicare Part B Fee for Service Medical claims
Sample Convenience sample of Medicare beneficiaries, including nearly 89% of the US population aged 65 years and older, as well as 3.3% of the US population younger than 65, including persons disabled due to blindness
VEHSS Topics Included Service Utilization
Medical Diagnoses
Years Analyzed 2014, 2015
Approximate Size 30 million persons per year

The analysis of Medicare claims for the Vision and Eye Health Surveillance System (VEHSS) includes beneficiaries who were fully enrolled in Medicare Part B Fee-for-Service (FFS) for the duration of 2014 and 2015.

Medicare claims represent a convenience sample that includes approximately 30 million individuals annually. Data from patients enrolled in Medicare managed-care plans were not included, as these plans do not include individualized claims for services.  In 2018, 2.2 million Americans were enrolled in Medicare advantage plans.

Medicare covers ophthalmologic services for nearly the entire US population aged 65 and older, for people younger than 65 who have received social security benefits as a result of disability for 24 months; for people who have end stage renal disease and receive dialysis or a kidney transplant; and for people who have amyotropic lateral sclerosis (ALS). Like others with a disability, people with US defined blindness (a best corrected acuity of 20/200 or worse in the better-seeing eye) become eligible for Medicare after 24 months of social security enrollment. In 2015, approximately 42.5 million out of 47.8 million Americans aged 65 and older (88.9%) were enrolled in Medicare Part B (which covers outpatient services).[1] Because of this high coverage rate, those enrolled are roughly representative of the overall population aged 65 and older. In contrast, only 9 million out of 273.6 million Americans aged 0 to 64 (3.3%) were enrolled in Medicare, and because these individuals are primarily eligible via disability, they are disproportionately sicker and poorer than other Americans in this age group.[2]  Additionally, Medicare does not cover all services. Routine eye exams and optometry services are not covered by Medicare except in rare circumstances.

NORC and its subcontractor KPMG LLP obtained access to 100% Medicare FFS claims data through the Centers for Medicare and Medicaid Services (CMS) Virtual Research Data Center (VRDC). Medicare data included a number of analytic files containing FFS claims organized into files by type of care, such as carrier files (also known as the Physician/Supplier Part B claims files), outpatient files, as well as denominator files (with information on eligibility and enrollment).  Through the VRDC, the project team had access to 100% CMS research identifiable files (RIFs), including:

  • Inpatient.
  • Outpatient.
  • Skilled Nursing Facility.
  • Hospice.
  • Home Health.
  • Carrier.
  • Durable Medical Equipment (DME).
  • Master Beneficiary Summary File (MBSF) Base File.
    • MBSF Chronic Conditions segment file.
    • Part D Event data.
    • Part D Characteristics, including Drug, Pharmacy, Prescriber, and Plan characteristics.

Please see the Research Data Assistance Center websiteExternal for a CMS description of each file.

Analysis Overview

VEHSS analyzed the 2014 and 2015 100% Medicare FFS claims databases to estimate the annual prevalence rate of treated diagnoses and the rate of clinical procedures. KPMG analyzed the data and generated de-identified summary reports of frequencies and rates, summarized by state and by age group, race/ethnicity, and sex. NORC further analyzed the summary data files, mapping outcomes to VEHSS-defined categories, calculating confidence intervals, and cleaning data. Results were further suppressed if the numerator was <3 and the denominator was less than 30, or the numerator was ≥3 and the denominator was ≤30.

A detailed description of the analytical steps is described in the report “VEHSS Claims & Registry Data Analysis Plan Cdc-pdf[PDF – 579 KB]External.” Full analysis documentation is included in the “VEHSS Medicare Data Report Cdc-pdf[PDF – 1.5 MB]External.”

Service Utilization–Eye Exams

VEHSS currently analyzes one category of Service Utilization–the proportion of Medicare beneficiaries who have an eye exam annually. The Eye Exam indicators analyzed in Medicare claims data are listed in Table 1.

Table 1. Service Utilization Indicators Analyzed in VEHSS

Service Utilization Indicators Analyzed in VEHSS
Category Subgroup
Eye Exams By provider type
By ophthalmologists and other physicians
By optometrists and opticians

Medical Diagnoses

VEHSS categorizes diagnosis codes into medical diagnosis categories and subgroups. Individual Medicare beneficiaries were assigned to diagnosis categories and subgroups based on International Classification of Diseases (ICD) 9 (permissible in 2014) or ICD10 diagnosis codes on any patient claim during the year of observation. As reported in the “VEHSS Diagnosis Code Categories and Crosswalk,” we identified all eye and vision related ICD10 diagnosis codes, and organized them into a two-level categorization structure, including 17 categories and 79 subgroups, as listed in Table 2.

Table 2. Medical Diagnosis Indicators Analyzed in VEHSS


Medical Diagnosis Indicators Analyzed in VEHSS
Category Subgroup
Retinal Detachment and Defects
Diabetic Eye Diseases Early/mild diabetic retinopathy
Moderate/severe non-proliferative diabetic retinopathy
Proliferative diabetic retinopathy
Diabetic macula edema (dme, csme)
Other/unspecified diabetes related eye conditions
Age-Related Macular Degeneration (AMD) AMD, unspecified
Early AMD
Dry-form AMD
GA, modifier for Dry-form
Wet-form AMD
CNV, modifier for Wet-form
Other Retinal Disorders Retina vascular disease, occlusive (arterial, venous)
Central retinal vein occlusion
Branch retinal vein occlusion
Central retinal arterial occlusion
Branch retinal artery occlusion
Retina vascular disease, non-occlusive
Macular edema (if not diabetic)
Hereditary chorioretinal dystrophy
Myopic degeneration
Other/unspecified retinal disorders
Glaucoma Open-angle glaucoma
Primary open-angle glaucoma
Low-tension glaucoma
Glaucoma suspect
Primary angle-closure glaucoma
Narrow-angle glaucoma
Congenital glaucoma
Neovascular glaucoma
Other/unspecified glaucoma
Cataracts Senile cataract
Non-congenital cataract
Congenital cataract
Posterior capsular opacity
Aphakia and other disorders of lens
Disorders of Refraction and Accommodation Myopia
Other disorder of refraction and accommodation
Blindness and Low Vision Unqualified visual loss, both eyes
Unqualified vision loss in one eye, or unspecified visual loss
Vision impairment one eye
Moderate or severe vision impairment better eye; profound vision impairment of lesser eye
Moderate or severe vision impairment both eyes
Profound vision impairment, bilateral, or legal blindness
Strabismus and Amblyopia Strabismus
Injury, Burns and Surgical Complications of the Eye Injury
Surgical complication
Disorders of Optic Nerve and Visual Pathways Optic nerve disorders
Visual pathway disorders
Other Visual Disturbances Visual field defect
Color blindness
Night blindness
Other/unspecified visual disturbances
Infectious and Inflammatory Diseases Infectious diseases
Eyelid infection and inflammation
Other inflammatory conditions
Lacrimal system and orbit inflammation
Orbital and External Disease Congenital anomalies
Other/unspecified orbital or external disease
Lacrimal diseases
Eyelid disorders
Dry eye syndrome
Disorders of the globe
Cancer and Neoplasms of the Eye Malignant neoplasm of the eye
Benign neoplasm of the eye
Cornea Disorders Keratoconus
Endothelial dystrophy (inc Fuchs)
Other corneal disorders
Other Eye Disorders

Denominators used to Calculate Prevalence Rates

The denominator for each estimated rate is the total number of beneficiaries in that demographic category who were fully enrolled in the Medicare Part B program for all 12 months during the year of observation.

Potential Limitations

The VEHSS analysis of Medicare claims is subject to a number of potential limitations:

  • Medicare claims are intended for billing purposes only. Diagnosis information included on claims is intended to justify payment. Therefore, diagnosis data on claims may suffer from bias or limited detail.
  • Medicare FFS does not cover all healthcare services, such as routine eye exams or optometry care. Medicare patients may utilize these services using a different payer, and thus these services are not captured in Medicare FFS claims.
  • Patients may be insured by multiple insurers, such as a supplemental, medigap or Medicare managed care plans. Thus, even normally covered ophthalmology services may not be indicated in FFS claims if services were reimbursed by another plan.
  • Many Medicare patients move seasonally. We report patient residence using the last location of observation. This may skew patient numbers towards “sun belt” states.
  • Medicare is not nationally representative for individuals younger than 65 years. These patients may obtain Medicare coverage due to medical need, such as legally recognized disability, or other specially defined benefit, such as end-stage renal disease. Individuals who become disabled for reasons of blindness cannot be distinguished from others who are disabled unless their visual condition of low vision and blindness is recording in their medical claims.
  • Medicare FFS is nearly representative of the population aged 65 and older, but does not include beneficiaries with Medicare advantage plans, people who defer Medicare coverage, or services paid out of pocket.

[1] US Census Bureau. Profile america facts for features: CB17-FF.08. Washington, DC: Economics and Statistics Administration; 2017. Accessed March 1, 2018.

[2] State Health Facts: Menlo Park, CA: Kaiser Family Foundation. Accessed March 1, 2018.