Photoreceptor Layer Thickness Changes During Dark Adaptation Observed With Ultrahigh-Resolution Optical Coherence Tomography

• Main Authors: Schottenhamml, Julia (Author), Maier, Andreas (Author), Pugh, Edward N. (Author), Lu, Chen David (Contributor), Lee, ByungKun (Contributor), Fujimoto, James G (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science (Contributor), Massachusetts Institute of Technology. Research Laboratory of Electronics (Contributor)
• Format: Article
• Language: English
• Published: Association for Research in Vision and Ophthalmology (ARVO), 2018-03-21T17:44:45Z.
• Subjects: Article
• Online Access: Get fulltext

PURPOSE. To examine outer retinal band changes after flash stimulus and subsequent dark adaptation with ultrahigh-resolution optical coherence tomography (UHR-OCT). METHODS. Five dark-adapted left eyes of five normal subjects were imaged with 3-μm axialresolution UHR-OCT during 30 minutes of dark adaptation following 96%, 54%, 23%, and 0% full-field and 54% half-field rhodopsin bleach. We identified the ellipsoid zone inner segment/outer segment (EZ[IS/OS]), cone interdigitation zone (CIZ), rod interdigitation zone (RIZ), retinal pigment epithelium (RPE), and Bruch's membrane (BM) axial positions and generated two-dimensional thickness maps of the EZ(IS/OS) to the four bands. The average thickness over an area of the thickness map was compared against that of the dark-adapted baselines. The time-dependent thickness changes (photoresponses) were statistically compared against 0% bleach. Dark adaptometry was performed with the same bleaching protocol. RESULTS. The EZ(IS/OS)-CIZ photoresponse was significantly different at 96% (P < 0.0001) and 54% (P = 0.006) bleach. At all three bleaching levels, the EZ(IS/OS)-RIZ, -RPE, and -BM responses were significantly different (P < 0.0001). The EZ(IS/OS)-CIZ and EZ(IS/OS)-RIZ time courses were similar to the recovery of rod- and cone-mediated sensitivity, respectively, measured with dark adaptometry. The maximal EZ(IS/OS)-CIZ and EZ(IS/OS)-RIZ response magnitudes doubled from 54% to 96% bleach. Both EZ(IS/OS)-RPE and EZ(IS/OS)-BM responses resembled dampened oscillations that were graded in amplitude and duration with bleaching intensity. Half-field photoresponses were localized to the stimulated retina. CONCLUSIONS. With noninvasive, near-infrared UHR-OCT, we characterized three distinct, spatially localized photoresponses in the outer retinal bands. These photoresponses have potential value as physical correlates of photoreceptor function.
National Institutes of Health (U.S.) (Grant 5-R01-EY011289-30)
National Institutes of Health (U.S.) (Grant UL1TR001064)
United States. Air Force. Office of Scientific Research (Grant FA99550-12-1-0499)
United States. Air Force. Office of Scientific Research (Grant FA9550-15-1-0473)