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Li J, Liu T, Flynn OJ, Turriff A, Liu Z, Ullah E, Liu J, Dubra A, Johnson MA, Brooks BP, Hufnagel RB, Hammer DX, Huryn LA, Jeffrey BG, Tam J. Persistent Dark Cones in Oligocone Trichromacy Revealed by Multimodal Adaptive Optics Ophthalmoscopy. Front Aging Neurosci 2021; 13:629214. [PMID: 33767618 PMCID: PMC7985087 DOI: 10.3389/fnagi.2021.629214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/09/2021] [Indexed: 11/13/2022] Open
Abstract
Dark cone photoreceptors, defined as those with diminished or absent reflectivity when observed with adaptive optics (AO) ophthalmoscopy, are increasingly reported in retinal disorders. However, their structural and functional impact remain unclear. Here, we report a 3-year longitudinal study on a patient with oligocone trichromacy (OT) who presented with persistent, widespread dark cones within and near the macula. Diminished electroretinogram (ERG) cone but normal ERG rod responses together with normal color vision confirmed the OT diagnosis. In addition, the patient had normal to near normal visual acuity and retinal sensitivity. Occasional dark gaps in the photoreceptor layer were observed on optical coherence tomography, in agreement with reflectance AO scanning light ophthalmoscopy, which revealed that over 50% of the cones in the fovea were dark, increasing to 74% at 10° eccentricity. In addition, the cone density was 78% lower than normal histologic value at the fovea, and 20-40% lower at eccentricities of 5-15°. Interestingly, color vision testing was near normal at locations where cones were predominantly dark. These findings illustrate how a retina with predominant dark cones that persist over at least 3 years can support near normal central retinal function. Furthermore, this study adds to the growing evidence that cones can continue to survive under non-ideal conditions.
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Affiliation(s)
- Joanne Li
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Tao Liu
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Oliver J Flynn
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Amy Turriff
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Zhuolin Liu
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Ehsan Ullah
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Jianfei Liu
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Alfredo Dubra
- Department of Ophthalmology, Stanford University, Palo Alto, CA, Unites States
| | - Mary A Johnson
- Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Brian P Brooks
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Robert B Hufnagel
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Daniel X Hammer
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Laryssa A Huryn
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Brett G Jeffrey
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Johnny Tam
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
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