Abstract
Purpose :
Spectral domain optical coherence tomography (SDOCT) imaging has revealed thinning in ETDRS subfields of sickle cell retinopathy (SCR) eyes compared to controls at baseline. The purpose of this longitudinal study is to explore rates of thinning in sickle versus control eyes and associations with systemic disease.
Methods :
Sickle cell and control subjects were prospectively enrolled from a university retina clinic into this observational study. Subjects underwent visual acuity testing, slit lamp biomicroscopy, dilated ophthalmoscopy, SDOCT imaging and SCR staging at baseline and follow-up. ETDRS subfield measurements were compared between sickle cell and control subjects and amongst sickle cell hemoglobin (Hgb) subtypes over time. Associations between change in ETDRS retinal thinning and Hgb subtype, SCR stage and systemic diseases were assessed.
Results :
606 sickle cell (308 pts) and 98 control eyes (54 controls) had median visual acuities of 20/20. There were 378 Hgb SS eyes (191 pts), 164 Hgb SC eyes (84 pts and 64 Hgb SThal eyes (33 pts). Follow-up was available for 315 sickle (160 SC pts) and 26 control eyes (18 pts). The median follow-up was 3.2 years (range = 0.01 to 9.76 years). SCR stage remained stable for 95% at 1 year, 94% at 2 years and 90% of eyes at 5 years. In contrast, the visual acuity decreased 1.7 (0.58) lines per year (p = 0.004) for SCR eyes. Compared with control eyes, SCR eyes showed significant thinning for CST [-0.70 (0.23)u/yr vs. 1.08 (0.56)u/yr, p = 0.043], ETDRS inner nasal subfield [-1.45 (0.20)u/yr vs. 0.67 (0.75)u/yr, p = 0.004], inner superior subfield [-1.95 (0.20)u/yr vs. 0.18 (1.06)u/yr, p = 0.009] but not in other ETDRS subfields. Rates of thinning were greatest for Hgb SC in CST [-1.54 (0.62)u/yr in SC, -0.25 (0.2)u/yr in SS, and -1.13 (0.37) u/yr, p = 0.04], inner nasal [-2.28 (0.51)u/yr in SC, -0.98 (0.16)u/yr in SS, and -1.9 (0.48) u/yr, p = 0.008] and inner superior subfields [-2.66 (0.45)u/yr in SC, -1.51 (0.22)u/yr in SS, and -2.22 (0.52) u/yr, p = 0.03]. Rate of thinning was more severe for patients with hypertension (HTN) and acute chest syndrome (ACS) but independent of diabetes, stroke or current use of hydroxyurea.
Conclusions :
Over time, sickle cell eyes exhibit faster rates of thinning in CST and nasal/superior subfields compared with controls and was most severe for Hgb SC subtype and with HTN and ACS diseases.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.