Abstract
Purpose: :
Epiretinal membrane (ERM) is a common complication of uveitis, though its effects on macular morphology and visual acuity (VA) may vary. We quantitatively investigated uveitic ERM on optical coherence tomography (OCT) and correlated these measures with VA, cystoid macular edema (CME) and other morphologic alterations in the macula.
Methods: :
Clinical records of 80 eyes of 54 patients with a diagnosis of uveitis and ERM formation as confirmed by spectral domain OCT (SDOCT) were retrieved from files and subjected to cross sectional and longitudinal analysis. Baseline characteristics at the time of ERM diagnosis and at last follow up (FU) examination were also noted. SUN guidelines were used for uveitis anatomical classification and inflammation activity. Raw SDOCT data were analyzed using a validated custom grading software, 3D-OCTOR. ERM boundaries were marked within 3D-OCTOR and a thickness map was regenerated. Macular ETDRS grid areas were used to compare thickness and surface area of ERM. Poor vision was defined as VA less than 20/40. General estimating equations and partial correlations were used which adjusted for the correlation between eyes within the subjects. T-tests were used for analysis that included only one eye per subject.
Results: :
Mean duration of uveitis before diagnosis of ERM was 91 months. Mean FU time for ERMs was 32 months. Mean distance VA was 20/40 at last FU. Thirty four eyes underwent cross sectional analysis of morphometric characteristics of the ERMs. Mean ERM thickness in the central subfield of ETDRS grid was 6.1 µm. Increased mean ERM thickness in fovea(12.3 µm) was correlated with poor VA (p<0.05). Mean ERM thickness in parafoveal area and over the entire ETDRS grid were not associated with low VA. ERM thickness was significantly correlated with longer duration of ERM (p<0.05). Presence of ERM over the foveal center, CME, disturbed foveal contour, higher central subfield thickness, disrupted IS-OS junction and focal ERM attachment to the retina were also significantly related with poor VA (p<0.05).
Conclusions: :
In uveitis, increasing foveal ERM thickness is associated with poor vision. SDOCT can aid define visual prognosis by demonstrating ERM characteristics, foveal morphology and photoreceptor layer integrity.
Keywords: uveitis-clinical/animal model • imaging/image analysis: clinical