Purpose:
To report the findings of repeated full-field electroretinogram (ERG) examinations in patients in long term therapy with hydroxychloroquine (HCQ) or chloroquine (CQ) without signs of retinal dystrophy at fundus examination
Methods:
We analyzed 19 patients ( 15 females and 4 males, mean age 55,8±15,6) affected by various autoimmune disorders. All patients underwent a complete eye examination and full-field ERG repeated from a minimum of 2 to a maximum of 5 times. No one of the patients had signs of maculopathy at fundus examination. The mean drug dose assumed was 3231.684 gr. in a mean period of 83.84 months. The stimulation parameters followed the ISCEV full-field ERG guidelines. The electrodes utilized were the erg-jet contact lens. For all the registered traces the peak time and amplitudes were detected and analyzed. For the statistical analysis multivariate linear regression models for repeated data were used.
Results:
The peak time results in the follow-up were stables, except the light-adapted b peak time, that showed a significant increase (p≤0.002). The a and b amplitudes had a biphasic trend, with an overall reduction in the last test, significant (p≤0.01) in dark-adapted combined rod-cone response. The most regular decrease was found in the light-adapted 30 Hz flicker (p≤0.006, fig.1).A limit relationship with dose was found for the b amplitude of the combined rod-cone response.
Conclusions:
Despite new examinations, like Multifocal Electroretinogram, established as early detectors of CQ and HCQ retinopathy and full-field ERG is now considered to show abnormalities only in late toxicity, in our longitudinal follow-up repeated full-field examinations reveal significant functional loss also in absence of fundus maculopathy. These findings could be useful in the drug management.
Keywords: electrophysiology: clinical • macula/fovea • clinical (human) or epidemiologic studies: natural history