Abstract
Purpose :
This is a pilot study to identify markers on ultrawide field scanning laser ophthalmoscopy (UWF-SLO) imaging that may help detect the presence of macular edema.
Methods :
This is a retrospective cohort study of patients who had spectral domain optical coherence tomography (SD-OCT), and non-mydriatic UWF-SLO testing during the same clinic visit. The study included only adult patients who were seen between (August to December 2017), and had clear ocular media allowing both imaging modalities. Chart review was conducted with analysis of OCT scans, and UWF-SLO (200° field) images. Data collection included age, gender, presence or absence of macular edema, and central macular thickness (CMT). Sub analysis of UWF-SLO images examining for macular bowtie birefringence was done using three filters modes: green-only laser images (532 nm laser), red-only laser images (635 nm laser), and color composite images (simulated white light, green and red filters= 50%:50%).
Results :
162 patients were included (254 eyes), with a mean age of 62.9±15.3 years old (87 females and 75 males). Age related macular degeneration was found in 30 patients (55 eyes, 34 dry, 21 wet), while 76 patients had diabetes mellitus (120 eyes with diabetic retinopathy). Macular edema (ME) was detected on SD-OCT in 95 eyes. The mean CMT when bowtie birefringence was detected in all three UWF-SLO image modes was 262.2±36.9 micrometers (µm), and was 359.8±151.1 µm when no bowtie was detected at all. The presence of bowtie birefringence in red-only laser images significantly decreased the odds of having ME (odds ratio 0.06±0.07; p-value: 0.008), while presence of bowtie birefringence in green-only laser images was found to be marginally significant in decreasing the odds of having ME (odds ratio: 0.44±0.2; p-value: 0.058).
Conclusions :
UWF-SLO is a non-mydriatic imaging technology that is used in routine clinic settings, and in telemedicine screening for peripheral retinal pathologies. The presence of macular bowtie birefringence may be a useful sign decreasing the odds of macular edema in clinical or telemedicine programs. Larger prospective studies are needed to further clarify the role of macular birefringence in UWF-SLO images.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.