Abstract
Purpose: :
Although previous studies have shown macular focal thinning in about 50% of all eyes in patients with sickle cell hemoglobinopathy (SCH) using spectral domain optical coherence tomography (SD-OCT), the functional impairment caused by these structural changes is unknown as most patients are visually asymptomatic. This study detects the functional impairment by scanning laser ophthalmolscope (SLO) microperimetry (MP) testing in SCH patients with macular thinning found on SD-OCT.
Methods: :
In this prospective, comparative, investigational study, SCH patients and visually healthy control subjects underwent SD-OCT and MP testing with the OPKO Spectral OCT/SLO microperimeter. Based on SD-OCT findings, patients were grouped into those with focal macular thinning (Group A) and those without thinning (Group B). Main outcome measures were mean retinal sensitivities as measured by MP and mean macular thicknesses in the 9 Early Treatment Diabetic Retinopathy Study (ETDRS) subfields as detected on SD-OCT.
Results: :
37 eyes of 19 SCH (SS, SC, and S-Thalassemia) patients (17 eyes in Group A and 20 eyes in Group B) and 34 eyes of 34 age similar visually healthy controls were included. Mean age and mean log MAR best corrected visual acuity between Groups A and B were not statistically different (p = 0.64 and 0.93, respectively). Group A had significantly thinner retinas compared with Group B in the parafoveal superior (p = 0.019), parafoveal temporal (p < 0.004), parafoveal inferior (p = 0.003), perifoveal superior (p = 0.04), perifoveal temporal (p = 0.0005), and perifoveal inferior (p = 0.045) subfields. The overall mean MP retinal sensitivities of Group A were significantly less than those of Group B (14.2 dB vs. 16.5 dB, p = 0.00005). Mean MP retinal sensitivities of Group B was not statistically different from controls (16.5 dB vs. 16.7 dB, p = 0.63).
Conclusions: :
SCH patients with focal macular thinning present on SD-OCT have significantly decreased retinal sensitivities compared to those without focal thinning or visually healthy controls based on mean MP sensitivities. MP is a sensitive measurement of macular function in patients with SCH.
Keywords: vascular occlusion/vascular occlusive disease • imaging/image analysis: clinical • perimetry