Original StudyPHOTODYNAMIC THERAPY FOR EXTRAFOVEOLAR CHOROIDAL OSTEOMAMazloumi, Mehdi MD, MPH*; Dalvin, Lauren A. MD*,†; Ancona-Lezama, David MD*; Mashayekhi, Arman MD*; Shields, Carol L. MD*Author Information *Ocular Oncology Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania; and †Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota. Reprint requests: Carol L. Shields, MD, Ocular Oncology Service, Suite 1440, Wills Eye Hospital, 840 Walnut Street, Philadelphia, PA 19107; e-mail: email@example.com Support provided in part by the Eye Tumor Research Foundation, Philadelphia, PA (C.L.S.) and the Heed Ophthalmic Foundation, San Francisco, CA (L.A.D.). None of the authors has any conflicting interests to disclose. The funders had no role in the design and conduct of the study, in the collection, analysis, and interpretation of the data, and in the preparation, review, or approval of the manuscript. C. L. Shields has had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Retina: May 2020 - Volume 40 - Issue 5 - p 966-971 doi: 10.1097/IAE.0000000000002534 Buy Metrics AbstractIn Brief Purpose: To evaluate the outcome of photodynamic therapy (PDT) in the management of extrafoveolar choroidal osteoma. Methods: The authors performed a retrospective chart review of all patients with choroidal osteoma that did not involve the foveola and were treated with standard-fluence PDT. Results: Nine eyes with extrafoveolar choroidal osteoma were studied. Mean logarithm of the minimum angle of resolution best-corrected visual acuity at initial examination was 0.07 (Snellen ∼20/25). The osteoma was treated with 1 (8/9) or 2 (1/9) PDT sessions using 50 J/cm2. After a mean follow-up of 49 months, the treated area of osteoma demonstrated complete (4/9) or partial (5/9) regression, with a mean of 73% regression in the PDT-treated areas. Tumor growth in the region of PDT was noted in 3 cases (3/9) (one tumor toward the foveola and two tumors at the margin away from the foveola), but in no case did the tumor reach the foveola. Therefore, PDT controlled tumor growth in 8 of 9 cases with only 1 of 9 cases showing growth through the PDT scar into foveola. Mean logarithm of the minimum angle of resolution visual acuity at last follow-up was 0.04 (Snellen ∼20/20) (P = 0.59). Conclusion: Photodynamic therapy is an effective modality for the management of extrafoveolar choroidal osteoma, minimizing tumor growth toward the foveola and preserving visual acuity. Photodynamic therapy was effective in the prevention of tumor growth toward the foveola and in preservation of visual acuity in eight of nine eyes with vision-threatening extrafoveolar choroidal osteoma.