Retinal Photoreceptor Outer Segment Length Before and After Light Stimulation - a Pilot Study

Assessment of Retinal Photoreceptor Outer Segment Length With Optical Coherence Tomography Before and After Light Stimulation - a Pilot Study

It has been shown that reactions of human retinal photoreceptors to a light stimulus can be measured with custom-made, research prototype optical coherence tomography (OCT) systems. This can be used as a biomarker for the function of the photoreceptors. Due to the high technical demands on the system, however, the technique is currently not available for clinical purposes. In this pilot study a protocol to measure changes in retinal photoreceptor layer thickness before and after light stimulation shall be developed based on a commercial OCT system and newly developed algorithms. Other variables, such as circadian processes shall be investigated as well. After measurements in healthy volunteers, the protocol is planned to be applied in patients with primary open angle glaucoma (POAG) and age-related macular degeneration (AMD) to test for feasibility of the method in these patient groups.

Inclusion Criteria:

• men and women aged over 18 years
• signed informed consent form
• ametropia below 3 diopters
• ability and willingness to follow instructions

for healthy volunteers:

• normal ophthalmologic findings

for primary open angle glaucoma patients (POAG):

• diagnosed POAG
• MD <= 10 dB

for age-related macular degeneration (AMD):

• diagnosed dry AMD
• diagnosed stage II or stage III AMD

Exclusion Criteria:

• Presence of any abnormalities preventing reliable measurements
• Ocular inflammation and ocular disease interfering with the study aims
• Use of photosensitizing medication (phototoxic drugs, photoallergic drugs) in the 3 months preceding the study
• Presence of any condition with the possibility of causing photosensitivity, including systemic lupus erythematosus SLE, Porphyria, Vitiligo, Xeroderma Pigmentosum and Albinism
• Presence of any form of epilepsy
• Ocular surgery in the 3 months preceding the study
• Pregnancy, planned pregnancy or lactating
• Any medical or surgical history, disorder or disease such as acute or chronic severe organic disease