Author: Duygu Yalinbas Yeter (Turkey)
Co-authors: Erman Bozali, Husne Kocak, Aynur Engin
Crimean-Congo hemorrhagic fever (CCHF) is an acute viral hemorrhagic fever with a high mortality rate. The disease could lead to a mild form of ocular disease consist of subconjunctival and retinal hemorrhages. In this study, we aimed to evaluate the retinal and choroidal structural changes in Crimean-Congo hemorrhagic fever (CCHF).
Sivas Cumhuriyet University, Departments of Ophthalmology and Infectious Disease
This prospective and observational study included 38 eyes of 19 patients over 17 years of age diagnosed with CCHF and 76 eyes of 38 age and sex-matched healthy controls. After a complete ophthalmologic examination, central foveal thickness (CFT), retinal nerve fiber layer (RNFL) analysis, were evaluated from the images obtained via spectral domain optical coherence tomography. Also, choroidal thickness was measured at 5 different points (750 and 1500 μm from the foveal center in the temporal and nasal quadrants and beneath the fovea) by using choroidal mode. Total choroidal area (TCA), luminal area (LA) and choroidal vascularity index (CVI) were calculated using the binarization method in ImageJ image analysis software. CVI was defined as the proportion of LA to the TCA. The disease severity classification was made according to the systemic findings and laboratory parameters of the patients. All ophthalmic examinations and measurements were performed during the active phase of CCHF.
The mean age of 19 patients was 34,3 ± 14,7 years of whom 7 (36,8%) were female. There was no significant difference between groups regarding CFT (p=0.2). The mean RNFL thickness in all quadrants and choroidal thickness at 5 points were significantly higher in CCHF patients compared to the control group (p<0,05, for all). TCA and LA were 1,12 ± 0,26 mm2 and 0,75 ± 0,17 mm2 in CCHF patients and 1.02±0.22 mm2 and 0.68±0,14mm2 in the control group respectively (p<0,05). Even though TCA and LA were statistically higher in the CCHF group, there was no significant difference in terms of CVI between groups (p=0,7). There was no significant association between TCA, LA and CVI and disease severity in patients with CCHF.
Crimean-Congo hemorrhagic fever may cause an increase in choroidal and RNFL thickness due to endothelial dysfunction, increased capillary permeability and increased systemic inflammatory response. Despite a significant increase in TCA and LA without an increase in CVI may be explained by the fact that the inflammatory changes in the CCHF cause dilation not only in the luminal area but also in the stromal area.