Predictive Utility of Visual Evoked Potentials in Detection of Ocular Changes in Paediatric Sickle Cell Patients: A Cross-sectional Analytical Study

Introduction: Ocular manifestations are one of the complications of Sickle Cell Disease (SCD) that may occur in various segments of the eye. Optic nerve involvement is under-diagnosed though it can be involved as a sequela to ischemia. Prediction of disease at an early age aids in better diagnosis. Visual Evoked Potentials (VEP) helps to detect abnormalities (silent lesions) in patients with visual complaints who do not present with visible pathological ophthalmological changes. In literature search, no study has been undertaken to assess the predictive utility of VEP regarding subclinical ocular changes in paediatric age group of SCD patients.

Aim: To evaluate predictive utility of VEP to identify subclinical ocular changes in paediatric patients of SCD and to record associated Visual Reaction Time (VRT).

Materials and Methods: In this cross-sectional analytical study, 30 cases (SCD patients) and 30 normal children in age group 3-15 years were evaluated by ophthalmic examination followed by VRT and VEP using Light-emitting diode (LED) goggles (Flash). Statistical analysis included descriptive (percentages) and inferential statistics presented as unpaired t-test, linear regression curve, Pearson’s correlation coefficient, coefficient of determination (R2) and β (regression) coefficient. The analysis was done at 99% confidence interval with significance at p<0.01.

Results: There was statistically significant prolongation of P100 latency in both eyes in paediatric cases when compared to normal children (P<0.01). N75-P100 amplitude, interocular difference showed no significant changes. When P100 latency was correlated with VRT, there was weak positive correlation (r=0.207, p=0.1278 for right eye, r=0.238, p=0.0801 for left eye). Though sensitivity of flash LED goggle VEP was 70%, specificity was high (96.66%). Positive predictive value was 95.45%.

Conclusion: These findings show that VEP can be used as a predictive measure (tool) to detect subclinical changes in absence of ocular complaints and normal ophthalmological findings.