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Compare the published Medicare service mix of Matthew Liam O'sullivan, MD, PHD with clinicians in the same registry specialty: Ophthalmology.

COLORADO SPRINGS, CO · Exact areaEdit location

2024 published service data · 27 eligible profiles compared. Similarity describes billing patterns, not quality, outcomes, or suitability for your care.

Narine Viruni, MD

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Injection of drug into eye (67028)
  • Photography of the retina (92250)
81%Service-mix similarityView profile →

Cecinio Castillo Ronquillo, MD, PHD

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Injection of drug into eye (67028)
  • Photography of the retina (92250)
78%Service-mix similarityView profile →

Ryan Mckay Rich, MD

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Injection of drug into eye (67028)
  • Photography of the retina (92250)
77%Service-mix similarityView profile →

Mark Andrew Weisbrod, MD

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)
  • Injection of drug into eye (67028)
69%Service-mix similarityView profile →

John Mose Roberts, M.D.

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Injection of drug into eye (67028)
  • Photography of the retina (92250)
64%Service-mix similarityView profile →

Michael G. Haas, M.D.

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)
  • Photography of the retina (92250)
63%Service-mix similarityView profile →

Zachary Mortensen, MD

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)
  • Photography of the retina (92250)
61%Service-mix similarityView profile →

Scott M Smetana, M.D.

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)
  • Photography of the retina (92250)
60%Service-mix similarityView profile →

Sheron Buckland Marshall, MD

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)
  • Photography of the retina (92250)
60%Service-mix similarityView profile →

Paul D Rastrelli, M.D.

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)
  • Photography of the retina (92250)
58%Service-mix similarityView profile →

Charles Dewey Mcmahon, M.D.

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)
  • Photography of the retina (92250)
58%Service-mix similarityView profile →

Nathan Rhodes Stevens, D.O.

Ophthalmology · Colorado Springs, CO

Shared published services
3 shared services · view billing descriptions
  • Imaging of retina (92134)
  • Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)
  • Established patient complete exam of visual system (92014)
57%Service-mix similarityView profile →
How this comparison works

We use the same calendar year of CMS Medicare Physician & Other Practitioners data for both providers. Published non-drug service counts are combined by HCPCS code across places of service. We apply log(1 + count), normalize the vectors, and compare them using cosine similarity.

Candidates share the reference provider’s current NPPES primary taxonomy and match the location you enter. We examine up to 500 candidates in NPI order, then show up to 12 with the highest positive similarity within that set. The score is not a percentile, medical recommendation, or prediction. Suppressed services are not estimated. Medicare fee-for-service data does not describe a provider’s entire practice.

Source: CMS Medicare Physician & Other Practitioners - by Provider and Service : 2024-12-01 · Published May 21, 2026.