Question: What diagnosis code should we use for OCT when the patient is currently on Plaquenil but not yet showing signs of macular degeneration, and there is no other diagnosis available that meets the CMS LCD requirements? Wyoming Subscriber Answer: There is probably no way you can get reimbursed for optical coherence tomography (OCT) to check whether a drug a patient is taking is affecting his vision. For a Plaquenil check, the appropriate ICD-9 code would be a V code such as V58.69 (Long-term [current] use of other medications), with the patient's systemic condition -- the reason he's taking the drug (such as 714.x, Rheumatoid arthritis and other inflammatory polyarthropathies) -- as a secondary diagnosis. But those diagnosis codes are not on most carriers' lists of approved ICD-9 codes for 92135 (Scanning computerized ophthalmic diagnostic imaging, posterior segment [e.g., scanning laser], with interpretation and report, unilateral). Why not? Payers are apparently not convinced that OCT is an effective way to detect Plaquenil retinopathy (PR). The OCT, unlike the visual field tests (92081-92083), requires that the results of the scan indicate some type of pathology. Subjective visual complaints are also not allowable diagnoses in Medicare's view. However, if optometrists can prove to the insurance carriers that the OCT can see PR earlier than a visual field test and dilated macular exam, then the diagnosis might be approved for OCT -- much like the glaucoma diagnoses (365.x) have already been.