Abstract
Purpose :
To determine rates of retinal nerve fiber layer (RNFL) and temporal macular thinning in patients with sickle-cell hemoglobinopathy.
Methods :
Post hoc analysis of patients enrolled in a prospective study of sickle-cell retinopathy was performed. Patients with sickle-cell disease, hemoglobin C disease, or thalassemia followed annually for ≥1 year were included. Eyes with glaucoma, ocular opacities, other retinopathies, and previous retinal procedures were excluded. Patients underwent Spectral-domain optical coherence tomography (OCT) of the macula and optic nerve head (ONH) using the Heidelberg Spectralis (Heidelberg Engineering, Inc, Carlsbad, CA, USA) at enrollment and subsequent visits.
Large macular scans (9x7.5 mm, 31 line scans) encompassing the entire Early Treatment Diabetic Retinopathy (ETDRS) subfields and neighboring temporal regions were obtained. Thicknesses in the temporal ETDRS field and far temporal field when the ETDRS subfield target was manually moved temporally were recorded at each time point. For the ONH scan, measurements of RNFL thickness in a 3.45 mm scan circle centered on the optic disc were recorded globally and in each ETDRS sector. Data analysis was performed in R statistical software using linear mixed-effects models to calculate average rates of thinning. Rates were compared to known normals.
Results :
A total of 54 eyes of 30 patients with mean age of 32.4±10.3 years at enrollment were included. Mean follow-up was 54.0±22.6 months (range 15 to 79) for macular scans and 44.9±22.2 months (range 12 to 79) for ONH scans. The mean temporal macular thickness was 267.4±18.9 µm at baseline and 263.7±18.6 µm at last follow-up (P value <0.001). Temporal macular thickness decreased at a rate of 0.60 (95% CI 0.32 to 0.88) µm/year and the far temporal macular thickness decreased at a rate of 0.53 (95% CI 0.27 to 0.79) µm/year.
The mean global ONH RNFL thickness was 102.1±12.9 µm at baseline and 98.8±15.1 µm at last follow-up (P value <0.01). Global ONH RNFL thickness decreased at a rate of 0.58 (95% CI 0.32 to 0.83) µm/year. The inferonasal and inferotemporal sectors had greatest rates of thinning at 1.02 (95% CI 0.46 to 1.58) and 0.98 (95% CI 0.50 to 1.46) µm/year, respectively.
Conclusions :
Temporal macular and ONH RNFL thicknesses decrease over time. The rate of global ONH RNFL thinning in this cohort of sickle-cell patients is similar to that reported in older normal eyes.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.