June 2013
Volume 54, Issue 15
ARVO Annual Meeting Abstract  |   June 2013
The cone outer segment termination (COST) line appears abnormal on OCT scans of patients with stationary and progressive forms of cone dysfunction
Author Affiliations & Notes
  • Ari Schuman
    Psychology, Columbia University, New York, NY
  • Rithambara Ramachandran
    Psychology, Columbia University, New York, NY
  • Xian Zhang
    Psychology, Columbia University, New York, NY
  • David Birch
    Retina Foundation of Southwest, Dallas, TX
  • Donald Hood
    Psychology, Columbia University, New York, NY
    Ophthalmology, Columbia University, New York, NY
  • Footnotes
    Commercial Relationships Ari Schuman, None; Rithambara Ramachandran, None; Xian Zhang, Topcon Inc. (C); David Birch, Acucela (C), QLT (C), Neurotech, USA (C); Donald Hood, Topcon, In (F)
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 3634. doi:
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      Ari Schuman, Rithambara Ramachandran, Xian Zhang, David Birch, Donald Hood; The cone outer segment termination (COST) line appears abnormal on OCT scans of patients with stationary and progressive forms of cone dysfunction. Invest. Ophthalmol. Vis. Sci. 2013;54(15):3634.

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      © ARVO (1962-2015); The Authors (2016-present)

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On frequency domain optical coherence tomography (fdOCT) scans, a line is often present between the inner segment ellipsoid (ISe) and retinal pigment epithelium (RPE), and is sometimes called the cone outer segment termination (COST) or misnamed Verhoeff’s membrane.[1] To better understand this feature, we examined fdOCT scans in patients with diminished cone function.


Horizontal line scans through the fovea were obtained with fdOCT (Heidelberg) from 30 healthy control eyes, 10 eyes with achromatopsia (ACHM), and 8 eyes with cone dystrophy (CD).[2] All patient eyes had reduced or absent cone full-field ERGs. Scans were qualitatively examined for the presence and appearance of a COST line. The ISe (aka IS/OS) line and RPE borders were marked using a computer-aided manual procedure.[2] The intensity of the COST region (Fig. 1), the area between ISe line and proximal retinal RPE border, was divided by RPE intensity.[2] The central fovea (±1mm) was not included as the ISe is often abnormal in these patients.[2,3]


Of 30 control scans, 29 had a distinct COST line in part of the temporal and/or nasal retina (Fig. 1A). 9 of 10 ACHM, and all CD patients, showed some sign of a COST line. However, in 8 of 9 ACHM [4] and all CD patients, this line appeared abnormal. The COST line was “blurred” (Fig. 1B) in 1 ACHM and 2 CD. The COST region was diffuse (Fig. 1C) in 9 ACHM and 4 CD. There was little to no COST line (Fig. 1D) in 1 ACHM. The RPE thickness was greater than the mean of controls in 9 of 10 ACHM (Fig. 1D) and 5 of 8 CD, although not in a statistically significant way. The COST regions in CD (0.79±0.06, p <0.01) and ACHM (0.78±0.06, p<0.001) were significantly less intense than in controls (0.94±0.05), but not different from each other. The intensity of the RPE was not significantly different among groups.


The COST line is absent, blurred, or diffuse in patients with abnormal cone receptor function, and these abnormalities can be quantified with an intensity measure. Although the COST line is typically not visible in all portions of scans from controls, its complete absence or abnormal appearance may be a useful clinical indicator of abnormal cone receptors. 1. Spaide & Curcio Retina, 2011, 2. Hood et al. IOVS, 2011, 3. Birch et al. IOVS, 2011, 4. Thomas et al. Ophthalmol, 2011.

Fig. 1. A, Control. B-D Patients.
Fig. 1. A, Control. B-D Patients.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 689 retina: distal (photoreceptors, horizontal cells, bipolar cells) • 696 retinal degenerations: hereditary  

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