Abstract
Purpose :
To assess agreement between binocular assessment of optic disc cupping and objective evaluation with the RetCam-III imaging system in premature infants . To look for changes in optic disc cupping in premature infants during period of retinal maturation.
Methods :
A cohort of premature infants screened for retinopathy of prematurity(ROP) were examined prospectively after consent recorded from parents. At Timepoint I(31 – 36 weeks), the vertical optic disc cupping(vCDR) was assessed clinically by the paediatric ophthalmologist through a 28D lens. Two RetCam-III fundus images centred on the optic discs were taken. A blinded assessor measured the vertical cup-disc-ratio from the 2 images and the average vCDR was calculated. This examination was repeated at Timepoint 2(37– 40 weeks), to track changes in vCDR. Intraocular pressures were taken with the indentation tonometer, I-Care II [Finland] to ensure that IOP was not >21mmHg. Exclusion criteria included abnormality in cornea, enlarged cornea size (>10.0mm) and abnormal eye. Statistical analysis included paired t-test for comparison of difference between vCDR over time. Consistency between the 2 methods was assessed with intraclass correlation coefficient(ICC). Bland-Altmann plots were used for agreement analysis.
Results :
In total, 126 eyes from 63 premature infants were examined, 504 images were taken and assessed during the study period of 12 months. The average vCDR by clinician was 0.30(SD:0.1) and by RetCam III was 0.32(SD:0.1). Paired t-test showed significant change in vCDR between the 2 time-points for infants with birthweight group 1000-1499g (p=0.001) and 600 – 999g(p=0.024). The ICC was 0.72(OD) and 0.71(OS) respectively at Timepoint I. At Timepoint 2 they were 0.59 and 0.70. These values showed moderate correlation, but values were not identical. Bland-Altman plot showed a wide 95% limits of agreement(-0.24, 0.26).
Conclusions :
Optic disc cupping with clinical estimation is not interchangeable with RetCam values. RetCam imaging is important for objective documentation when deviation from normal mean vCDR is noted on clinical examination. Mean optic disc vertical cupping in this population was 0.3. Birthweight <1500g show variation of vCDR over time.
This is a 2020 ARVO Annual Meeting abstract.