Predictive parameters on CT scan for dysthyroid optic neuropathy

AIM:To evaluate the value of parameters on CT scan in predicting dysthyroid optic neuropathy(DON)and to provide guidance for early diagnosis of DON accordingly.METHODS:A total of 67 eyes of 35 patients with thyroid-associated ophthalmopathy(TAO)were included in this study.Patients were divided into 2 groups(DON group and non-DON group).Parameters were measured on high resolution CT,including muscle index(MI),superior ophthalmic vein(SOV)dilatation,extraocular muscle volume/orbit volume(MV/OV),and intracranial fat prolapsed,and be compared between these 2 groups.The relation between those parameters and visual function[visual acuity(VA)and visual field defect(VF defect)]were also evaluated.RESULTS:MI and MV/OV were significantly higher in DON group(P=0.00035 and P=0.00026).No significant difference was detected regarding intracranial fat prolapse existence and SOV dilatation(P=0.37 and P=0.15).MV/OV was found to have significant negative correlation with both VF defect(R=-0.332,P=0.0273)and VA(R=-0.635,P=0.00)while MI was found to have negative linear correlation with VA only(R=-0.456,P=0.00017).The area under receiver operating characteristic curves was 0.82 for MV/OV and 0.75 for MI.The best performance in detecting DON was achieved when MV/OV is set at 0.20 with 72%sensitivity and 87%specificity and MI is set at 0.52 with 64%sensitivity and 80%specificity.CONCLUSION:MI and MV/OV are predictive parameters for DON.Together with clinical manifestations,MV/OV≥0.2 can be used as a good indicator for DON in TAO patients.

Therapeutic difference between orbital decompression and glucocorticoids administration as the first-line treatment for dysthyroid optic neuropathy:a systematic review

To assess all available data to compare the efficacy of glucocorticoids treatment and orbital decompression for dysthyroid optic neuropathy(DON).PubMed,EMBASE,the Cochrane Library databases as well as other sources were searched by two independent reviewers followed by extensive hand-searching for the identification of relevant studies.The primary outcomes were the improvement in visual acuity and responder rate.Secondary outcomes were the proptosis reduction,change in diplopia,and clinical activity score(CAS).One randomized controlled trial,three retrospective case series and one prospective case series met the inclusion criteria.They were divided into intravenous high-dose glucocorticoids(ivGC)group and orbital decompression(OD)group.Both groups demonstrated improvement in visual acuity.In addition,the proportion of patients with improved vision in OD group was higher than that in ivGC group(P<0.001).Post-treatment proptosis reduction was also reported in both groups.Overall,weighted mean in proptosis reduction estimated at 1.64 and 5.45 mm in patients treated with ivGC and OD respectively.This study also presented results regarding pre-existing and new-onset diplopia.Apart from diplopia,a wide variety of minor and major complications were noted in 5 included studies.The most common complication in ivGC group and OD group was Cushing's syndrome and epistaxis respectively.The present systematic review shows that both glucocorticoids treatment and OD are effective in treating DON and OD may work better in improving visual acuity and reducing proptosis.However,high-quality,large-sample,controlled studies need to be performed in the future.

Reduced choroidal peripapillary capillaries in thyroid-associated ophthalmopathy with early stage of dysthyroid optic neuropathy

AIM: To investigate whether the subtle change of choroidal/retinal vessel densities and volumes in thyroidassociated ophthalmopathy(TAO) could be an early sign to detect dysthyroid optic neuropathy(DON). METHODS: This was a retrospective cross-sectional study, and a total of 98 eyes from 50 subjects were enrolled under certain criteria. Thirty-four eyes of normal controls and 64 eyes of TAO, including 39 eyes of DON and 25 eyes of TAO without DON, underwent optical coherence tomography angiography(OCTA) scanning. All the tested parameters of OCTA scanning including choroid radial peripapillary capillaries(RPC), retinal nerve fiber layer(RNFL), and macular ganglion cell complex(GCC) were compared among groups, and the correlation between OCTA parameters and visual function parameters was also investigated. RESULTS: Whole choroidal RPC was significantly reduced in DON(48.24%±0.4978%) compared to normal(50.33%±0.3173%) and TAO without DON(49.16%±0.5463%;P=0.0041). The reduction of whole choroidal RPC was also correlated with visual field(VF) defect in DON(r=0.5422, n=39). Although vision acuity and VF were improved in all the patients with DON after being treated with medical and surgical decompression, the reduction of RPC density were not reversed.CONCLUSION: There is a notable reduction in choroidal RPC in DON, which is correlated with VF defect. The reduction of RPC density could not be reversed immediately by medical and surgical decompression even when vision and VF were improved. These findings suggest that choroidal RPC could be a useful parameter to diagnose and monitor early stage of DON.

Modified endoscopic transnasal orbital apex decompression in dysthyroid optic neuropathy

Background:To describe the surgical technique and assess the clinical efficacy and safety of modified endoscopic transnasal orbital apex decompression in the treatment of dysthyroid optic neuropathy.Methods:In this retrospective research,forty-two subjects(74 orbits)who underwent modified endoscopic transnasal orbital apex decompression for the treatment of dysthyroid optic neuropathy were enrolled.Preoperative and postoperative best-corrected visual acuity(BCVA),visual field mean deviation(MD),Hertel exophthalmometry,and new onset diplopia were assessed before and after the intervention.The Wilcoxon test was used for differential analysis.Linear mixed-models’analyses were conducted to assess the potential predictors for BCVA change.Results:Postoperatively,the mean BCVA improved from 0.70±0.62 logMAR to 0.22±0.33 logMAR.BCVA significantly improved in 69 eyes(93%),remained stable in 4 eyes(5%)and deteriorated in 1 eye(1%).MD of visual fields improved from−13.73±9.22 dB to−7.23±7.04 dB.Proptosis decreased from 19.57±3.38mm to 16.35±3.01mm.Preoperative BCVA,MD of visual fields and medical rectus diameter were independent factors associated with improvements in BCVA(P<0.05)by linear mixed-models’analyses.Eighteen patients(42.9%)developed new diplopia postoperatively.Conclusion:Modified endoscopic transnasal orbital apex decompression effectively restores vision in dysthyroid optic neuropathy.

The effect of orbital radiation therapy on thyroid-associated orbitopathy complicated with dysthyroid optic neuropathy

Thyroid-associated orbitopathy （TAO） is an inflammatory autoimmune disorder. The most serious complication of TAO is dysthyroid optic neuropathy （DON）, which can lead to permanent vision loss because of volume expansion in the orbital apex. Orbital radiation therapy （ORT） is an anti-inflammatory treatment used in the treatment of active TAO. Clinical studies support radiotherapy as having a modest effect on DON, and early radiotherapy may protect against disease progression to DON. Current studies suggest that radiotherapy is generally safe. However, risks still exist in some cases. The possible effects of radiotherapy on TAO, especially complicated with DON, are reviewed. The effects of radiotherapy on DON are not completely known, and evidence from standardized, prospective, and multicenter clinical trials is still lacking.

Orbital decompression surgery for the treatment of Graves＇ ophthalmopathy：comparison of different techniques and long-term results

AIM： To evaluate the long-term results of different orbital decompression techniques performed in patients with Graves＇ ophthalmopathy（GO）.METHODS： Totally 170 cases with GO underwent orbital decompression between 1994 and 2014. Patients were divided into 4 groups as medial-inferior, mediallateral（balanced）, medial-lateral-inferior, and lateral only according to the applied surgical technique. Surgical indications, regression degrees on Hertel exophthalmometer, new-onset diplopia in the primary gaze and new-onset gaze-evoked diplopia after surgery and visual acuity in cases with dysthyroid optic neuropathy（DON） were compared between different surgical techniques.RESULTS： The study included 248 eyes of 149 patients. The mean age for surgery was 42.3±13.2 y. DON was the surgical indication in 36.6% of cases, and three-wall decompression was the most preferred technique in these cases. All types of surgery significantly decrease the Hertel values（P〈0.005）. Balanced medial-lateral, and only lateral wall decompression caused the lowest rate of postoperative new-onset diplopia in primary gaze. The improvement of visual acuity in patients with DON did not significantly differ between the groups（P=0.181）. CONCLUSION： The study show that orbital decompression surgery has safe and effective long term results for functional and cosmetic rehabilitation of GO. It significantly reduces Hertel measurements in disfiguring proptosis and improves visual functions especially in DON cases.