Optical coherence tomography (OCT) scan artifacts are seen surprisingly frequently, adversely affect retinal thickness measurements in a high proportion of cases and are diagnosis-dependent, according to Investigators at Duke University Eye Center in Durham, NC.

The researchers conducted a retrospective observational case series aimed at determining the frequency and type of optical coherence tomography (OCT) fast macular thickness map (FMTM) scan artifacts, and whether these artifacts depend on patient diagnosis, demographics and ocular therapy. The study included records from 171 eyes of patients who had undergone ophthalmologic evaluation by a Duke University Eye Center vitreoretinal faculty member, and who had had an OCT scan produced by the FMTM protocol between July 7, 2003, and July 31, 2003. Researchers determined the relationships between OCT scan artifacts and ocular diagnosis, ocular treatment and patient demographics. They used logistic regression to relate OCT scan artifacts simultaneously with ocular diagnosis and treatment.

Retinal scan artifacts, though not observed in normal eyes, were identified frequently in eyes with macular pathology. Artifacts were observed in 43.2 percent of all scans; of these, an erroneous retinal thickness measurement was obtained in 62.2 percent. Six types of OCT surface map artifacts were observed. Of these, inner and outer retinal misidentification, degraded image artifact and "off center" artifact were significantly associated with central thickness calculation errors. Neovascular age-related macular degeneration (AMD), full-thickness macular hole and photodynamic therapy were all associated with increased artifact. The authors believe that recognition of these artifacts will improve retinal thickness measurement accuracy, and will prevent faulty treatment decisions that are based on inaccurate retinal thickness measurements.