Objectives

To investigate retinal microstructure of patients affected with malattia leventinese (MLVT) and mutation in the EFEMP1 gene using high-resolution optical coherence tomography (OCT).

Methods

Patients diagnosed with MLVT received a comprehensive eye exam, full-field and multifocal electroretinogram testing and imaging with a high-resolution Fourier domain OCT (Fd-OCT, UC Davis Medical Center, Davis, USA; axial resolution: 4.5 microm, acquisition speed: 9 frames s(-1), 1000 A scans s(-1)) combined with a flexible scanning head (Bioptigen Inc. Durham, NC, USA).

Results

Two related patients aged 30 and 60 years, with MLVT and identified c.R345W mutation in the EFEMP1 gene, were tested. Mother and daughter showed a variable phenotype with reduced vision function in the younger patient, whereas the mother had a 'form frustre'. Fd-OCT revealed extensive or focal sub-retinal pigment epithelium (RPE) deposits, separation of RPE and Bruch's membrane, and disruption of the photoreceptor outer and inner segment layers. No outer retinal changes were visible outside areas with sub-RPE deposits.

Conclusion

Retinal structure in EFEMP1 retinal dystrophy is reflected by morphological changes within the RPE/Bruch's membrane complex with accumulation of sub-RPE material associated with disrupted photoreceptor integrity. The pattern of microstructural retinal abnormalities is similar but with a different extent in patients with variable phenotypes.

We describe a novel instrument capable of acquiring, simultaneously, adaptive optics enhanced scanning laser ophthalmoscopy and optical coherence tomography (OCT) images of the human cone mosaic in vivo. The OCT system is based on transversal scanning of the sample with a line scan rate of 14 kHz, approximately 20 times faster than a previously reported instrument. We demonstrate the capability of this instrument with the measurement of the human cone spacing in perifoveal retina.

Recent developments in adaptive optics - optical coherence tomography (AO-OCT) allow for ultra-high isotropic resolution imaging of the in-vivo retina, offering unprecedented insight into its volumetric microscopic and cellular structures. In addition to this promising achievement, the clinical impact and application of this technology still needs to be explored. This includes assessment of limitations and challenges for existing as well as future AO-OCT systems, especially in the context of potential transfer of this technology from an optical bench to a portable imaging system. To address these issues we will describe our current AO-UHR-OCT focusing on its sub-components, as well as application for clinical imaging. Additionally, we describe some directions for future development of our AO-OCT instrument that would improve its clinical utility including: new compact AO-OCT design, new improved AO sub-system (extreme AO), and new generations of Fourier-domain-OCT. © 2008 SPIE.

Inner and outer retinal morphology were quantified in vivo for 6 nonglaucomatous and 10 glaucomatous optic neuropathy patients. Custom, ultrahigh-resolution imaging modalities were used to evaluate segmented retinal layer thickness in 3D volumes (Fourier-domain optical coherence tomography), cone photoreceptor density (adaptive optics fundus camera), and the length of inner and outer segments of cone photoreceptors (adaptive optics-optical coherence tomography). Quantitative comparisons were made with age-matched controls, or by comparing affected and nonaffected retinal areas defined by changes in visual fields. The integrity of outer retinal layers on optical coherence tomography B-scans and density of cone photoreceptors were correlated with visual field sensitivity at corresponding retinal locations following reductions in inner retinal thickness. The photoreceptor outer segments were shorter and exhibited greater variability in retinal areas associated with visual field losses compared with normal or less affected areas of the same patient's visual field. These results demonstrate that nonglaucomatous and glaucomatous optic neuropathies are associated with outer retinal changes following long-term inner retinal pathology.

Purpose

The purpose of this study is to evaluate the macular morphological changes associated with idiopathic epiretinal membrane (iERM) using high-resolution Fourier-domain optical coherence tomography (FD-OCT), as they correlate with visual acuity and microperimetry (MP-1).

Methods

In all, 24 eyes (19 subjects) with iERM were imaged prospectively using FD-OCT with axial resolution of 4.5 μm and transverse resolution of 10 to 15 μm. MP-1 and Stratus OCT were carried out in a subset of eyes.

Results

The mean log of the minimum angle of resolution best-corrected visual acuity (BCVA) was 0.18±0.16 (range: -0.08 to 0.48, Snellen equivalent 20/15(-1) to 20/60). ERM was visualized in all 24 eyes with FD-OCT and in 17 eyes (85%) of 20 eyes imaged with Stratus OCT. Although BCVA correlated with macular thickening in the central 1 mm sub-field of the Stratus ETDRS (P=0.0005) and macular volume (central 3 mm area) on FD-OCT (P<0.0001), macular thickening on thickness map and volume correlated poorly with decrease in macular sensitivity on MP-1 (P=0.16). On FD-OCT, foveal morphological changes correlated best with decrease in BCVA, the strongest being central foveal thickness (P<0.0001). Other significant changes included blurring of the foveal inner segment-outer segment (IS-OS) junction and/or Verhoeff's membrane, vitreal displacement of foveal outer nuclear layer and foveal detachment (P<0.05). Foveal IS-OS junction disruption was seen in 25% of eyes on Stratus OCT but in none of the eyes on FD-OCT.

Conclusion

FD-OCT allowed improved visualization of ERM and associated foveal morphological changes that correlated best with BCVA. Macular thickening correlated weakly with decreased macular function as assessed by MP-1.

Adaptive optics (AO) is used for improving lateral resolution in opthalmic Optical-Coherence-Tomography (OCT) to correct for the aberrations in the human eye. AO works by measuring aberrations using a wavefront sensor and applying this information to the control of a deformable mirror in a closed loop, thereby compensating for the measured aberrations. This instrument combines the advantages of FD-OCT and advanced microtechnology for AO, using 35-element bimorph deformable mirror. AO system can effectively compensate low-order aberrations and maintain low rms wavefront error during closed-loop operations.

We have combined Fourier-domain optical coherence tomography (OCT) with a closed-loop Adaptive Optics (AO) system. The AO-OCT instrument has been used for in vivo retinal imaging. High-lateral resolution of our AO-OCT system allows visualization of the microscopic retinal structures not accessible by standard OCT instruments. © 2005 SPIE and OSA.