Visual quality reduction and related factors in thyroid-associated ophthalmopathy

Abstract

Objective To evaluate visual quality and related factors in patients with thyroidassociated ophthalmopathy (TAO).Methods This was a prospective case-control study.A total of 38patients (72 eyes) with TAO and 35 healthy adults (70 eyes) underwent testing with OQAS Ⅱ,which uses a double-pass technique to evaluate the modulation transfer function (MTF),objective scatter index (OSI) and visual acuity at different contrast sensitivities (100％,20％,9％).Some clinical data was recorded in the patients with TAO,including best corrected visual acuity (BCVA),the disease duration,clinical activity scores (CAS),NOSPECS,proptosis,smoking habits,etc.Data were statistically analyzed with an independent samples t test,pearson or Spearman correlation analysis and a multiple regression analysis.Results The visual quality of patients with TAO showed decreases,with lower MTF (TAO 29.35±11.65,controls 42.97±7.38,t=-8.344,P＜0.01),higher OSI (TAO 0.89±0.84; controls 0.33±0.14,t=5.551,P＜0.01),lower VA100％ (TAO 0.96±0.40,controls 1.43±0.25,t=-8.522,P＜0.01),lower VA20％ (TAO 0.70±0.31,controls 1.05±0.26,t=-7.269,P＜0.01),and lower VA9％ (TAO 0.42±0.18,controls 0.64±0.19,t=-6.948,P＜0.01).The MTF in patients with TAO was correlated significantly with age,CAS,NOSPECS,proptosis,palpebral fissure height,intraorbital pressure and smoking (r=-0.281,-0.485,-0.489,-0.277,-0.469,-0.332,-0.502,P＜0.05).OSI in patients with TAO was correlated significantly with age,CAS,NOSPECS,intraorbital pressure and smoking (r=0.368,0.476,0.418,0.268,0.535,P＜0.05).There were no statistically significant differences in MTF or OSI for BCVA,duration of disease,thyroid function,intraocular pressure,diplopia or average amount of sleep.Multiple regression analysis revealed that CAS,NOSPECS,smoking and palpebral fissure height are risk factors for the MTF (R2=0.497,F=16.567,P＜0.01),while CAS and smoking were risk factors for OSI (R2=0.405,F=23.501,P＜0.01).Conclusion Visual quality of patients with TAO is reduced,with higher OSI,lower MTF,VA100％,VA20％ and VA9％.MTF is negatively correlated with CAS,NOSPECS,proptosis,palpebral fissure height,intraorbital pressure and smoking,while OSI is positively correlated with CAS,NOSPECS,intraorbital pressure and smoking.CAS,NOSPECS,palpebral fissure height and smoking are significant risk factors for the MTF (R2=0.497,F=16.567,P＜0.01); CAS and smoking are significant risk factors for the OSI (R2=0.405,F=23.501,P＜0.01). Key words: Thyroid associated ophthalmopathy; Visual quality; Double-pass technique ; Related factors