Long eye relief fundus camera and fixation target with partial correction of ocular longitudinal chromatic aberration

Abstract

A combined 32° full field of view refractive fundus camera and fixation target with a 20 to +10 diopter sphere correction range is described and demonstrated. The optical setup partially corrects the average longitudinal chromatic aberration and spherical aberration of the human eye, while providing a long eye relief to allow integration with reflective adaptive optics ophthalmoscopes, as a viewfinder. The fundus camera operates with 940 nm light, using a maximum 2.9 mm diameter imaging pupil at the eye. The fixation target uses a light projector capable of delivering red, green and/or blue spatially and temporally modulated stimuli to the retina. The design and performance of each subsystem are discussed, and retinal imaging at various wavelengths is demonstrated.

Assessment of binocular fixational eye movements including cyclotorsion with split-field binocular scanning laser ophthalmoscopy

“…FEMs range from approximately 11 to 60 arcsec (tremor) to 7.5 ± 1.5 arcmin (microsaccades) ( Bowers, Boehm & Roorda, 2019 ; Montes, Bennett, Bensinger, Rani, Sherkat, Zhao & Sheehy, 2022 ), which would put our method in the position to cover most fixational situations while the larger imaging rasters can be used as a retinal display system for retina-contingent visual psychophysics ( Yang, Arathorn, Tiruveedhula, Vogel & Roorda, 2010 ). Two independent Badal optometers allowed correction of ocular lower order aberrations, the largest factor decreasing image quality in ophthalmic imaging ( Steven, Sulai, Cheong, Bentley & Dubra, 2018 ). This design will allow to increase observation numbers in normal participants and patients, given that eyes do not have to be preselected based on favorable refractive states.…”

Assessment of binocular fixational eye movements including cyclotorsion with split-field binocular scanning laser ophthalmoscopy

“…Fixational eye movements range from ~11-60 arcsec (Tremor) to 7.5 ± 1.5 arcmin (Microsaccades) (Bowers, Boehm & Roorda, 2019;Montes, Bennett, Bensinger, Rani, Sherkat, Zhao & Sheehy, 2022), which would put our method in the position to cover most fixational situations while the larger imaging rasters can be used as a retinal display system for retina-contingent visual psychophysics (Yang, Arathorn, Tiruveedhula, Vogel & Roorda, 2010). Two independent Badal optometers allowed correction of ocular lower order aberrations, the largest factor reducing image quality in ophthalmic imaging (Steven, Sulai, Cheong, Bentley & Dubra, 2018). This will allow to increase observation numbers in normal participants and patients, given that eyes do not have to be preselected based on favorable refractive states.…”

In Vivo Assessment of Retinal Phenotypes in Axenfeld–Rieger Syndrome

“…Image sequences (videos) consisting of 150 to 200 frames were recorded at different locations using an internal fixation target (consisting of a crosshair projected onto a dichroic for the individual to view) to guide fixation. 32 The raw frames from each video were corrected for sinusoidal distortions as previously described. 33 Following this, a reference frame was automatically selected 34 for registration of 50 to 80 frames and averaged to produce an image with improved signal-to-noise ratio.…”