ASRS 2018: Imaging Session

James Lin, MD
Vitreoretinal Surgery Fellow
Bascom Palmer Eye Institute

Dr. Shaileen Parikh started the discussion this morning describing the clinical and OCT findings in chronic solar retinopathy, which is common in India where sun gazing in the morning is a religious ritual. It was a retrospective study of 36 patients, with results showing that 28 patients had bilateral presentations, with patients having subretinal yellow deposits, RPE mottling, and RPE defects. OCT findings showed central foveal thinning, lamellar macular hole, intraretinal cystic changes in the outer retina, interruption of external limiting membrane, disorganization of outer retinal layers, and collection of material with hyperreflectivity in the foveal space. The conclusion was that sun gazing can cause chronic solar retinopathy with reduced visual acuity, with characteristic changes on OCT and fundus examination.



Next, Dr. Matias Iglicki reported on a cohort of optic disc pit maculopathy presenting with neurosensory macular detachment in elderly patients that was initially diagnosed and treated as other causes of subretinal fluid. 59 patients with optic disc pit maculopathy were identified and evaluated with SD-OCT, with 15 patients correctly diagnosed at first. Those whom were correctly diagnosed were significantly younger than those misdiagnosed, and misdiagnosed eyes had significantly more outer retinoschisis at baseline and more RPE alterations at 6 months compared to those correctly diagnosed initially. Optic disc pit maculopathy may present later in life and mimic other diseases causing subretinal fluid, so awareness of the differential of elderly patients presenting with subretinal fluid is important to avoid inappropriate treatment.


Dr. Manish Nagpal then presented a study comparing OCT angiography features of serpiginous like choroiditis with ICG angiography. In particular, OCT angiography revealed areas of large flow void beneath RPE-Bruch’s membrane, which corresponded well to hypofluoresence on ICG angiography. Furthermore, these areas of flow void on OCT angiography were reduced post treatment, again corresponding to reduced hypofluorescent regions on ICG angiography. It is possible that these darkened areas on OCTA and ICGA represent ischemia mediated by inflammation, and that these vessels repopulate over time with treatment. Thus, OCT angiography can be used as a non-invasive tool to diagnose and assess treatment in patients with serpiginous like choroiditis.


Dr. Roger Goldberg reported on short-term oral mifepristone for the treatment of central serous chorioretinopathy (CSCR). Given the association between CSCR with cortisol, mifepristone (a high affinity GC receptor antagonist) may be effective. This was a prospective, randomized, multi-site, placebo controlled trial of 30 patients treated with mifepristone 300 mg, 900 mg, or placebo for four weeks in patients with chronic recurrent CSCR. Mifepristone treated patients had significant reduction in central retinal thickness and best corrected visual acuity, while placebo treated patients did not have a significant change in either of these parameters. However, comparison of central retinal thickness between these two groups did not reach statistical significance. Thus, oral mifepristone may reduce subretinal fluid and improve visual acuity in patients with CSCR.


Then, Dr. David Huang showcased the use of OCT angiography using a new algorithm that removes motion artifact for detecting non-exudative CNV, which is a risk factor for developing exudative CNV in eyes with intermediate AMD. Furthermore, the study investigated the natural history of these lesions. 64 eyes were followed for at least 24 months, and 9 eyes developed non-exudative CNV and 11 eyes developed exudative CNV. 7 of the 9 eyes with non-exudative CNV progressed to exudative CNV, with a Cox hazard ratio of 18:1. In conclusion, non-exudative CNVs pose a high risk of progressing to exudation and must be followed closely with regular screening by OCT angiography. More research will need to be done to determine if there is utility in prophylactic treatment of these lesions.


Dr. Sumit Sharma presented a study examining the use of swept source-OCT angiography in patients with uveitis to compare their findings to those found with angiography. 650 eyes with uveitis were imaged, and peripheral non-perfusion was well visualized using swept source-OCT angiography and wide field angiography. In patients with sarcoidosis, swept source-OCT angiography showed choroidal areas of flow void that were similarly seen on ICG angiography. However, swept source OCT angiography showed fewer lesions than ICG angiography in birdshot retinochoroidopathy. Swept-source-OCT angiography is an alternative imaging modality that rivals wide field fluorescein angiography and ICG angiography in the evaluation of patients with uveitis.


Next, Dr. Alexander Barash presented a study on the effects of acutely elevating intraocular pressure after intravitreal injections on retinal perfusion density using OCT angiography. This was a prospective study of 40 eyes receiving intravitreal bevacizumab or aflibercept. After injection, macular and peripapillary blood flow and retinal thickness were analyzed using OCT angiography, with findings of decreased angiographic perfusion density of superficial layers more than the deep layers. Additionally, there was evidence of decreased perfusion at the temporal optic nerve head. However, macular OCT thickness did not change significantly after injection.


Dr. Adrienne Scott delivered results from a study that correlated the degree of peripheral non-perfusion on ultra-widefield fluorescein angiography to macular vessel density on OCT angiography in patients with sickle cell disease. In particular, OCT angiography can be used to detect macular flow abnormalities in the deep plexus. Ischemic index on ultra-widefield fluorescein angiography showed a statistically significant correlation with vessel density on OCT angiography in the temporal subfield of the superficial capillary plexus and in all subfields of the deep capillary plexus. Therefore, peripheral non-perfusion is correlated with macular vessel density on OCT angiography in sickle cell patients.


Finally, Dr. Kasra Rezaei presented a study analyzing the use of ultra-widefield OCT angiography to evaluate peripheral retinal vascular density in patients with diabetic retinopathy. 20 patients with diabetic retinopathy (both proliferative and non-proliferative) underwent ultra-widefield OCT angiography. This technology was able to localize areas of neovascularization located in the peripheral retina and to evaluate the retinal vascular density index, vessel diameter index, and capillary flow impairment in these diabetic patients. In conclusion, this imaging modality can be used to monitor the progression of diabetic retinopathy.