Dysthyroid optic neuropathy (DON) is a sight threatening complication occurring in 35% patients with Graves orbitopathy. The medical treatment consists in the infusion of high dose of methylprednisolone (MP), while surgical orbital decompression is mandatory in patients non responding to the medical treatment. We aimed at studying the response to high dose steroids in DON and parameters for predicting therapy effectiveness. Twenty-three patients with DON were studied by complete ophthalmological evaluation. Visual acuity, Hardy Rand Ritter (HRR) for colour vision defects, visual field and fundoscopy were carried out in all patients at baseline and 1, 2 and 4 weeks after therapy. Twelve patients were treated with 500 mg while 11 with 1000 mg MP for 3 consecutive days over 2 weeks. Fourteen non responders patients were eventually decompressed. A complete DON recovery was observed in 5 and 11 patients who received 500 mg and 1000 mg MP, respectively. No response to treatment was observed in all 5 patients (21%) who at baseline showed optic disk swelling, 3 of whom treated with the lower and 2 with the higher steroid dose. At one month of follow-up a significant increase of the visual acuity (P < 0.004), an improvement of the colour perception (P<0.001) and of the visual field (defect P< 0.03 and pattern standard deviation P<0.01) were observed in responders. Non responders showed a significant decrease of pattern standard deviation (P<0.004), but only initial improvement with subsequent worsening was observed in all other parameters studied. Our data show that high dose MP may be effective in restoring visual function in about 40% of patients with DON. The efficacy of treatment was not dependent on MP dose but on the severity of baseline optic nerve function impairment. Severe colour vision impairment and visual field defects are parameters predictive of medical treatment failure.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector
05 - 09 May 2012
European Society of Endocrinology