| Objective:To evaluate the damages and recoveries of the visual function in idiopathic optic neuritis (ION), and the relations between the visual field defects and retinal nerve fiber layer thickness (RNFL).Design:prospective case series.Research object:44cases (52eyes) of patients with ION treated in Department of Ophthalmology the First Affiliated Hospital of Kunming Medical University in November2009to December2010and21follow-up monocular cases in these44patients whose visual functions were not fully recovered after the treatment.Methods:44patients (52eyes) diagnosed as ION performed the tests about the visual field with the standard Humphrey Automatic Perimetry (HPA), and the ones about RNFL thickness with the optical coherence tomography (OCT). These results were analyzed in the Superior (S), Inferior (I), Temporal (T), and Nasal (N) quadrants, even at the each o'clock point. The visual field and RNFL thickness of21monocular cases whose visual functions not fully restored were followed up in3,6and12months. The measurement data of visual field defects and RNFL thickness from the affected eyes and the contralateral eyes were all collected not only before treated, but also after treated for3months,6months,12months, and analyzed by the normal distribution test, the t test, or One-ANOVA test. The relationship between the visual field defect scores and RNFL thickness at the four quadrants and the twelve clock points were analyzed by the Pearson correlation analysis.Results:1. The characteristic of visual field in Idiopathic Optic Neuritis before treatmentThe types of visual field defects from affected eyes were multiple:Full field impairments (28.85%); hemianopsia (23.08%); arcuate scotoma (13.46%); central combined with paracentral scotoma, central scotoma combined with blind spot enlargement and atypical visual field defects (7.69%respectively); tubular vision and central scotoma (3.85%respectively); quadrantanopia and paracentral scotoma (3.74%,1.92%respectively). The involved quadrants of visual field defects in the16contralateral eye (36.36%):paracentral scotoma (31.25%); general sensitivity reduction (31.25%); blind spot enlargenment (12.50%); blind spot enlargenment combined with paracentral scotoma (12.50%); nasal step (6.25%); arcuate scotoma (6.25%). Visual field defects in affected eyes involved quadrant ranges:4quadrants (55.77%); infranasal and infratemporal quadrants (17.31%); supratemple and infratemporal quadrants (9.26%); supranasal and infratemporal and supratemporal quadrants (3.85%); supranasal and supratemporal quadrants (7.69%); infranasal and infratemporal and supratemporal quadrants (3.85%), supratemporal quadrant (1.92%). There was no cases involved in infratemporal, supranasal or infranasal quadrant respectively.The quadrant in which the point of highest visual field defect was:the infranasal quadrants were the most common, the lower fields were more than the upper ones, and the nasal fields were more than temporal ones. The highest visual field defects were distributed in10°(77.27%),10°～20°(18.18%) and out of30°(4.55%). The highest defects were in-17dB--37dB:less than-20dB (3.85%),-21～-30dB (17.31%), more than-30dB (78.85%).2. The characteristic of visual field in idiopathic optic neuritis after followed up in one year laterThe types of visual field defects from affected eyes were also multiple in followed12months:central scotoma or (and) paracentral scotoma (33.33%); full field impairment (19.05%); arcuate scotoma combined with central or paracentral scotoma (19.05%); tubular vision (14.29%); arcuate scotoma (9.52%); hemifield visual field defect (4.76%). Only3contralateral eyes involved acute ION appeared full field impairment, there was no abnormal defect in other contralateral ones. The involved qradrants of visual field defects in followed12months:4quadrants (42.86%); infranasal and infratemporal quadrants (28.57%); supranasal and supratemporal quadrants (14.29%); supranasal, infranasal and supratemporal quadrants (4.76%); infranasal, supranasal and infratemporal quadrants (4.76%); supranasal quadrants (4.76%). There was no cases involved in infratemporal, supratemporal or infranasal quadrant respectively. The highest visual field defects were distributed in10°(71.43%),10°～20°(28.57%). The highest defects were in-7dB--36dB:less than-20dB (28.57%),-21～-30dB (14.29%), more than-30dB (57.14%).3. The variation trend of retinal nerve fiber layer of idiopathic optic neuritis and visual field scoresThe average RNFL thickness of the affected eyes and contralateral ones before treatment were111.10±41.02μm and107.23±12.24μm. There's no significant difference between them (P=0.682). There're significant progressive defects in the affected eyes during the followed3,6and12month (F=10.329, P=0.000), whereas, there's no significant change in the contralateral eye (F=1.310, P=0.277). During the follow-up months, RNFL thickness in the upper, lower, nasal and temporal quadrants were gradually thinning. F values were4.840,4.678,4.685,8.64, respectively, P values were0.004,0.005,0.005,0.000, respectively. There's no signifant difference during the following months in the contralateral eyes. The differences of the average RNFL thickness between before treatment and in the followed3month,6month and12month after treatment were25.29±7.49μm,34.71±7.49μm and37.29±7.49μm respectively. P values were0.001,0.000,0.000respectively. The differences between3month and6month,12month were9.43±7.49μm (P=0.21) and12.00±7.49μm (P=0.11) respectively. The difference between6month and12month, was 2.57±7.48μm (P=0.73). The differences of the contralateral eyes in these montioned time period, had no stastical significance (P>0.05). The involved o'clock points of RNFL thickness in followed12months:12o'clock (11.36%),1o'clock (12.50%),2o'clock (6.82%),5o'clock (7.95%),6o'clock (6.82%),7o'clock (12.50%),8o'clock (4.55%),9o'clock (4.55%),10o'clock (12.50%) and11o'clock (13.64%). There were no defects of RNFL thickness at3or4o'clock.The difference of the visual field scores between before treatment and in the followed3month,6month and12month after treatment were4.33±2.00,5.24±2.00, and5.00±2.00respectively. P values were0.034,0.011, and0.015respectively. The differences between3month and6month,12month were0.90±2.00and0.67±2.00respectively. P values were0.65and0.74respectively. The difference between6month and12month, was0.238±2.00(P=0.91).4. The structure-function relationship in idiopathic optic neuritisThere're positive correlations between the Mean Defect (MD) and RNFL thickness of the lower quadrants in the followed3,6and12month, r values were0.524,0.570and0.697respectively, and P values were0.015,0.007and0.000respectively. There're positive correlations between MD and the average RNFL thickness in the followed6and12month, r values were0.591and0.772respectively, and P values were0.005and0.000respectively. There's a positive correlation between MD and RNFL thickness of the upper quadrants in the followed12month (r=0.588,P=0.009). There's no relationship between MD and RNFL thickness of the nasal and temporal quadrants during the followed months (P>0.05). There're negative correlations between the visual field scores and RNFL thickness of the lower quadrants in the followed3,6and12month, r values were-0.450,-0.426and-0.602respectively, and P values were0.041,0.050and0.004respectively. There's a negative correlation between the visual field score and RNFL thickness of the upper quadrants in the followed12month (r=-0.559, P=0.008). There're negative correlations between the visual field scores and the average RNFL thickness in the followed6and12month, r values were0.533and-0.602respectively, and P values were0.013and0.004respectively. There's no relationship between MD and RNFL thickness of the nasal and temporal quadrants during the followed months (P>0.05). There're positive correlations between MD and RNFL thickness at12,1,5,6and7o'clock after12months. r values were0.456,0.541,0.652,0.628and0.629, respectively, and P values were0.038,0.011,0.001,0.002and0.002, respectively. There're negative correlations between the visual field scores and RNFL thickness at12,1,5,6and7o'clock. r values were-0.454,-0.588,-0.538,-0.544and-0.567, respectively, and P values were0.039,0.009,0.012,0.011and0.007, respectively. There's no relationship between MD, the visual field scores and RNFL thickness at the other o'clock (P>0.05). According to the optic disc structure-function relationship of Garway-Heath [1], the range of the disc defects in the followed12month:VI zone (80.95%), II zone (57.14%), III zone (57.14%), V zone (52.38%), I zone (33.33%), and IVzone (9.52%); and the range of the visual field defects:VI zone (85.71%), I zone (80.95%), II zone (66.67%), IIIzone (57.14%), V zone (57.14%), and IV zone (42.86%). The consistent defects between the optic disc and the visual field:VI zone (76.19%), IIzone (47.62%), III zone (38.10%), V zone (38.10%), I zone (23.81%), and IV zone (4.76%).Conclusions:1. The types of visual field defects from the ION eyes were multiple. The most common involved quadrants of the visual field defects of ION were the whole4quadrants. The most common involved range of the highest visual field defect points were within10°. The highest visual field defects were more than-30dB. There's a improving trend in the ION visual field along with the time. But the central defects were more serious and more difficult to recover than the peripheral defects.2. RNFL thickness were progressively thinner and thinner in the ION patients whose visual functions had not always restored. It was likely the upper and lower poles that appeared RNFL defects firstly, and the lower one earlier than the upper one. The most common defects of RNFL and the visual field were nerve fiber bundle damages during the followed12months. They had the structure-function correspondence.3. There's a favourable coherence between the visual field scores and MD to evaluate the relationship between the structure defects and the function defects. |
PDF Full Text Request