Utility of isolated-check visual evoked potential technique in dysthyroid optic neuropathy

PURPOSE

To analyze the utility of isolated-check visual evoked potential (icVEP) for discriminating between eyes with dysthyroid optic neuropathy (DON) and eyes with thyroid-associated ophthalmopathy (TAO) but not DON.

METHODS

Forty-three eyes with TAO but not DON (as non-DON), fifty-three eyes with DON, and sixty healthy eyes (as controls) were included. Comprehensive ophthalmic examinations, including best-corrected visual acuity, refraction, color vision test, intraocular pressure measurement, slit-lamp biomicroscopy, ophthalmoscopy, RAPD, exophthalmometry measurements, pVEP test, icVEP test, standard automated perimetry, and clinical activity score classification of TAO, as well as demographic information, were collected and analyzed.

RESULTS

In the DON group, the signal-to-noise ratio (SNR) value of icVEPs decreased significantly compared with that of the non-DON group as well as control (p < 0.05). The SNR values under 8%, 16% and 32% depth of modulation (DOM) were significantly negatively correlated with BCVA (p < 0.05, r =  - 0.9 ~  - 0.6), papilledema (Y/N) (p < 0.05, r =  - 0.8 ~ 0.4) and DON (Y/N) (p < 0.001, r =  - 0.7 ~  - 0.5). The 8% DOM of icVEP had the largest area under the receiver operating characteristic curve (AUC) (0.842) for discriminating DON from non-DONs. Meanwhile, decision curve analysis (DCA) showed that patients clinically benefit most from 8% DOM of icVEP. Furthermore, the 8% DOM of icVEP combing with papilledema (Y/N) and BCVA (Model 1) has significantly larger AUC than the 8% DOM of icVEP (p = 0.0364), and has better clinical benefit in DCA analysis.

CONCLUSIONS

The SNR of 8% DOM from icVEP may represent a significant ancillary diagnostic method for DON detection. Furthermore, icVEP combined with papilledema (Y/N) and BCVA should be considered as a diagnostic model in future clinical practice.

Advances in the Treatment of Thyroid Eye Disease Associated Extraocular Muscle Myopathy and Optic Neuropathy

PURPOSE OF REVIEW

To review emerging treatments for thyroid eye disease (TED) associated extraocular muscle myopathy and dysthyroid optic neuropathy (DON).

RECENT FINDINGS

Emerging targeted biologic therapies may alter the disease course in TED. Teprotumumab, a type I insulin-like growth factor receptor inhibitor, is the most recent addition to the treatments available for TED-associated extraocular muscle myopathy causing diplopia. Small studies also suggest a potential therapeutic benefit for DON. Various recent studies have also expanded our knowledge on conventional TED therapies. The therapeutic landscape of TED and its sequelae has evolved in recent years. New targeted therapies have the potential to reduce the extraocular muscle and orbital volume expansion which can lead to diplopia and vision loss from optic nerve compression. Longer term efficacy and durability data is needed to determine the role biologics, such as teprotumumab, should play in the treatment of TED patients compared to the current standard of care.

Early efficacy of teprotumumab for the treatment of dysthyroid optic neuropathy: A multicenter study

Purpose

To study post-interventional findings in patients with dysthyroid optic neuropathy (DON) treated with teprotumumab.

Observations

In this multicenter observational Case series, patients with DON were treated with teprotumumab, an insulin-like growth factor I receptor inhibitor (10 mg/kg for the first infusion then 20 mg/kg for subsequent infusions, every three weeks for a total 8 infusions). This study included patients with acute and chronic thyroid eye disease (TED) with DON who had failed conventional therapies and were not candidates for surgical decompression. Data collected included best corrected visual acuity (BCVA), color vision, RAPD when present, and orbital CT or MRI. Proptosis, clinical activity score (CAS), Gorman diplopia score (GDS), and Humphrey visual fields (HVF) were also evaluated.

Ten patients (6 women, 4 men) with an average age 64 years old were included in this study. Mean follow up after completion of infusions was 15 weeks. Baseline visual acuity (VA) impairment ranged from hand motion (HM) to 20/25 in affected eyes. All patients had pre-treatment orbital CT or MRI that confirmed orbital apex compression. Seventy percent of patients had objective improvement in DON after 2 infusions of teprotumumab measured as significant improvement in visual acuity, resolution of RAPD, or both. After completion of treatment, affected eyes had a mean BCVA improvement of 0.87 logMAR (p=0.0207), proptosis reduction of 4.7 mm (p<0.00001), CAS improvement of 5.25 points (p<0.00001), and GDS improvement of 0.75 points (p=0.160). All 6 patients who presented with an RAPD had resolution or improvement of RAPD. All 7 patients who presented with color vision deficits had normalization or improvement of color vision.

Conclusions and Importance

Teprotumumab infusions resulted in medical decompression and objective resolution or improvement of dysthyroid optic neuropathy. Most patients had rapid improvement of visual acuity and reversal of RAPD. Post-infusion imaging demonstrated reduction in extraocular muscle size that correlated with improvement in visual dysfunction. However, patients who presented with longstanding severe visual loss had limited improvement. There was no recurrence of DON after completion of teprotumumab in our cohort.

•

Teprotumumab is effective for the treatment of dysthyroid optic neuropathy.

•

Most patients demonstrated rapid objective improvement after 2 infusions.

•

Visual acuity improved and relative afferent pupillary defect resolved after treatment.

•

Orbital imaging showed improvement of orbital apex crowding after treatment.

•

Patients with longstanding severe vision loss had limited improvement in visual acuity.