【作者】 宋跃；

【导师】 张晓光；

【作者基本信息】 吉林大学 ， 眼科学， 2007， 博士

【摘要】 通过人颅骨标本模拟人的颅部环境采用DH5937动态应变测试系统检测到不同部位和不同作用力撞击人颅骨后眼眶内壁筛骨为最容易受到应力作用的骨骼，遭受的应力、应变最大，是主应力方向。为临床上非爆裂性眶壁骨折病人中多伴发眶内壁骨折这一现象的发生机制提供了相应的理论依据。通过系统分析眼眶壁骨折病人眼外肌功能和视功能损伤的临床特征，重点提出了对爆裂性内、下以及内下眶壁爆裂性骨折的CT亚型分类的新观点和分类方法并报告了不同亚型病人眼外肌功能损伤的临床特点，这对相对定量评价和指导临床研究有临床实用价值。同时首次总结出东北地区引起爆裂性和非爆裂性骨折的首要致伤因素分别是殴斗和交通意外；爆裂性眶壁骨折病人眶内壁骨折发生率最高，眶内下壁骨折复视发生率最高、眼球内陷程度最重。眼球破裂伤和外伤性视神经病变分别是导致爆裂性和非爆裂性眼眶骨折病人发生视力损害的主要原因；伴有视神经管骨折的后部眶壁骨折患者的致盲率最高，应根据病人视力的具体情况决定激素和手术治疗方案。同时也论述了眼眶骨折整复手术残存复视的治疗原则和方法。更多还原

【Abstract】 The stress, stain and direction of principal stress of human orbital walls responding to the external forceon the skulls ----A mechanics study and its clinical significanceBackground Orbital blow-out fractures usually are represented by simple orbital wall fractures and the complexed fractures for non blow-out fractures which have more potential causing damages to orbital integrity and orbital content including extraocular muscles and ocular tissues. Clinically we have noticed that there are some orbital walls fractured at the position that was not attacked directly. No good data from biomechanics points of view to show which orbital wall are more often damaged when different forces attacked on different parts of the skull and why. So it is necessary to study by biophysical experiments to show the stain, stress and stress directions derived from the different orbital walls after the different parts of the skull were attacked by different stress of external forces. The results could be potentially useful to explain the mechanisms of accompanied orbital damages alone with the non blow-out fractures.Purposes To study the stain, stress and stress directions derived from the different orbital walls after the different parts of the human skull specimen were attacked by different stress of external forces in order to provide mechanics mechanism for non blow-out fractures and to verify if it is correlated with clinical phenomena.Methods 3 complete human skull specimens without soft tissues were used for this mechanics study. The sensors were placed onto the medial, inferior and external walls of the orbits to received signals of stress from skulls produced by hammer attacked on the skull and transmitted to the DH5937dynamic strain testing system. This system could collect all the data of stress, strain and directions of forces on different orbital walls which were transmitted from different parts of the skulls produced by force hammer with same and variable strength at different situations. Material mechanics theories were used to analyze the data. According to the primary mechanic study 55 case of non blow-out fracture clinical cases were analyzed for their accompanied orbital fractures to see if these data were correlated with experimental results. In most cases mobile accidents were the major causes. The CT data and clinical findings were reviewed by same group of CT doctors and ophthalmologists. The incidences of medial, inferior and external orbital wall fractures were statistically studied.Results When 3 Newton was applied on central frontal bone as well as other points on the skulls, the average stress and strain were 169.593 for medial wall, 43.549 for lateral wall and 11.130 for inferior wall. Same force applied on parietal bone produced average stress and strain as 74.459 on medial wall, 41.217 for inferior wall and 36.247 for lateral wall. When zygomatic bones were attacked the average stress and strains were 342.296 for medial wall, 70.815 for inferior wall and 11.862. The stresses and strains detected on lateral wall, inferior wall and medial wall were 630.248, 74.081 and 55.893 respectively for temporal bone. 46.979, 43.549 and 38.075 were produced and detected after the occipitals were attacked.On the bases of the first experimental results, the stress and strains received by medial walls were studied further by using different strength of forces applying on the same points. On each attacking point, 3、3.5、4.0、4.5、5.0 Newton were used. 96.206、119.656、128.649、130.262, 143.008 were detected from medial wall when frontal bones; 79.524、86.849、88.181、93.933、101.263were for parietal bone attacks; 79.524、86.849、88.181、93.933、101.263 for zygomatic bones; 35.217、36.876、39.852、43.487、57.486 for the temporal bone; 33.99、37.71、38.21、38.79、39.27 were recorded by attacking occipital bones.62.5% of 32 patients with non-blow-out orbital fractures were accompanied with medial wall fractures and the inferior wall was in second place.Conclusions1. When the same strength of forces applied to different part of the skulls, the more closer to the periorbital area, the stronger the stress and strain could be detected. And in most cases, the medial wall is the place comparing to other 2 walls receiving strongest stress and strain. The maximal stress and strain was detected in the medial wall when zygomatic bone was attacked. The only exception case is that the external wall received the strongest stress and strain when the force was applied to temporal bones.2. When different strength of forces attacked on the same part of the skull, alone with the increasing strength, the stress and strain detected at medial wall were also increased but not in a linear pattern.3. Clinical evidence showed that the medial wall fractures occurred in more than 60% of the patients with non blow-out orbital fractures and that was well correlated with the experimental data.4. This mechanics study could mimic and provide experimental status for periorbital fractures produced from skull traumas with direct results. The result from this study could be useful for the further study of the mechanisms of medial wall fractures involved in non blow-out periorbital fractures. The clinical characteristics of orbital fracturesand ocular mobility disturbance related studiesBackgroundAlong with the changes of life style, living status and modern technique developing in China as well as ophthalmologists knowing more about the orbital trauma, the incidence of orbital fractures seems to be increased rapidly in recent few years. The revolution of new medical materials let patients have more chances to be well treated surgically. Clinically diplopia, enophthalmos, numbness of inferior orbital area and CT evidence of orbital wall fractures could be used as symptoms and signs as the diagnostic criteria for orbital fractures also as the indications for surgical managements. Properties and extents of the orbital traumas are strongly related with the strength ,position and directions as well as the penetrating abilities of the external forces applied on the periorbital regions. The orbital traumas could be presented with simple non symptom blow-out fractures which were usually seen by ophthalmologists in the past to a very severer orbital bone displacement and ocular tissues damages as in non blow-out fracture patients. Orbital traumas often cause ocular tissues and optic nerve damages as well as orbital contents damages including extraocular muscle motility disturbances with the results of alterations of visual functions and ocular movement. The principle for the treatment of orbital traumas are mainly according to the severity of orbital damages and affecting on visual and ocular motilities. The procedure could be from simple observation to very complicated internal fixation techniques and application of implants into orbits. But for a long time clinical diagnosis and treatment were not mainly deducted by ophthalmologists and the classification of the orbital fractures ,evaluation of visual activities and ocular motilities were not the major concern by those none ophthalmologists professionals. Chinese ophthalmologists were just involved into this "own" field only in these few years to start the clinical and basic research works. There were few good and systemic clinical studies with large enough patients numbers and well followed to reflect the epidemiological clinical characteristics of orbital fractures in a defined populations to represent Chinese ophthalmologist’s experience. It has been noticed that the currently used clinical classification for orbital fractures is also not well defined to describe the relationships between morphological changes and the alteration of visual functions and ocular motility disturbance. According to the references the variations about the incidence and severity of visual damages and causes of blindness related with orbital traumas are quiet different with many conflictions. Not many good works could be found about the disturbances of ocular motilities for these patients. The diagnosis and especially treatment strategies for the traumatic optic neuropathy alone with orbital fractures that causing severer damages to visual functions with or without optic canal fracture detected are very challengeable topic. Surgical complications during and post orbital fracture repairing procedures have attracted many doctors concerns. The orbital fracture related strabismus pre- and post orbital reconstruction surgeries will be one of the major challenges for both orbital and strabismus surgeons. So it is necessary to conduct a systemic clinical study in a well defined patients load hospital on those patients from ophthalmologist’s points of view.Purposes:From the ophthalmologist’s point of view to systemically study the clinical epidemiological characteristics of orbital fracture patients in a well established university hospital eye center of northeast China central city, Changchun. The following aspects were studied : the basic epidemiology propeties of the patients; CT morphological changes and the necessity and criteria for the ocular motility related sub-classifications for blow-out orbital fractures; the clinical properties of some special types of orbital fractures, the orbital fracture related traumatic optic neuropathy with optic canal fractures and the outcome of the treatments as well as the risk factors affecting the visual activities; the effects of the timing of surgeries and the properties of extraocular muscle function damaged on the prognosis of the patients and also the principles for the treatment of orbital fracture related strabismus.Materials and methods:Clinical setting and patient general data:All 193 patients admitted during September 2002 and December 2004 were retrospectively investigated from medical files of the second clinical hospital of Jilin university, China.The everage age was 31 years old with 157 males and 36 females. The time interval between trauma and diagnosis were from 2 hours to 3 years. The follow-up times were 6 to 12 months.Clinical assessment:Routine ophthalmic examination include visual activity test with international visual test chart, slit lamb exam for the anterior segments and direct and indirect ophthalmoscope for ocular fundus, automatic visual field test, VEP and FFA. PHILIPS Marconi MX8000D CT was used for all patients to evaluate the orbital morphologies with axial, coronal scanning and 3D reconstructions if necessary.Classification of orbital fractures:In general, the orbital fractures without or with involvement of orbital rim wereclassified into blow-out orbital fracture and non blow-out fracture and the clinical.properties of the patients could be evaluated accordingly.Blow-out orbital fracture is the type of fractures without orbital rim damage wasfurther divided according to the position or the orbital wall involved into medial,inferior and medial-inferior orbital wall fractures.Non blow-out fractures belong to the fractures with periorbital bone fracturesand also called complex fractures. Following orbits related fractures are included:LeFortll fracture, LeFortlllfracture, naso-ethmoid-orbital fracture, external wallfracture, orbito-maxilo-zygomatic fractures.The proposal for the sub-classification of blow-out fractures:The isolated medial orbital fracture and inferior orbital fracture were classified to the subtypes respectively according to the location and morphological characteristics of the fractures.Type I medial orbital fracture was defined as that the whole ethmoid was comminuted broken and depressed, ethmoid sinus disappeared and its original spaces were filled with herniated fat tissues . The curvature and replacement of medial rectus muscle was obvious on CT scanning images. Type II medial orbital fracture was defined as the partial ethmoid fractured with ethmoid sinus mostly intact, but a morphologically angle-like image was formed between the fractured fragment of orbital wall and the ambient connective tissue around medial rectus muscle which could be wedged into the fracture area.Type I inferior orbital fracture was classified as that the large area of inferior orbital wall between infraorbital fissure and ethmo-maxillary fissure was broken and orbital content was entrapped into maxillary antrum. Type II inferior orbital fracture was quantified as that the area around infraorbital groove in the front of inferior orbital wall with broken fragment sloped into maxillary antrum, but the nasal edge of fragment was joined with inferior orbital wall and the connective tissue around inferior rectus muscle was similar with type II medial orbital fracture wedged into the fracture area.The medial-inferior orbital fractures could be divided into Ml-M type and Ml-I type accoeding to CT morphology changes after measuring and comparing thefractured area of the two walls involved.MI-M sub-type: When the fractured area on medial wall was larger than that ofinferirorwall, Ml-M sub-type could be defined;Ml-I sub-type: The fractured size of the inferior wall was larger than that of medialwall. When the fractured area were similar then the extent of orbital soft tissueherniation should be accounted for the subclaasification.Definitions for visual acuity alterations:No change: the patients have no complaint of decreased visual acuities and the difference of the best corrected visual acuities between the affected side and the contra lateral eye was within two lines.Slight decrease: the patients have complaint of decreased visual acuities and the difference of the best corrected visual acuities between the affected side and the contra lateral eye was over two lines.Low vision: patients complained obvious decrease of visual acuities with best corrected visual acuitie lower than 0.3.Blindness: Loss of vision after trauma and best corrected visual acuitie lower than 0.05.Hertel exophthalmometry was used for measurement of enophthalmos. Extraouclar muscle functions was investigated by candle double vision test and synoptophore.The criteria to analyze extraocular muscle function changes:(1) Crossed diplopia can be the major sign as paralysis of medial rectus muscle which could be determined by turning patients’ injured eye medially. And the distance between object and double vision image was more significant by using candle double vision test technique. Besides exotropia degree was found increased by synoptophore test. (2)Restriction of medial rectus muscle would let patients show accompanying same side diplopia when patients turned the involved eye laterally. And the distance between object and image become more obvious by using candle double vision test. Besides esotropia degree was increased by using synoptophore test.(3) Inferior diplopia could occur as the sign of paralysis of inferior rectus muscle when patients turned the involving eye lateral inferiorly to 15 degree. And the distance between object and image was further increased by using candle double vision test and vertical separated diplopia could be more significant when tested by using synoptophore and the involving eye position was higher than the opposite eye.(4)When patients turned the involved eye lateral superiorly to 15 degree, the superior diplopia could occur as the sign of restriction of inferior rectus muscle and the distance between object and image was further apart by candle double vision test with increased vertical separated diplopia while using synoptophore and the involved eye position was inferior to the opposite eye.(5)The sign for paralysis of inferior oblique muscle was the accompanying vertical diplopia when patients turned the involved eye medial superiorly to 15 degree. And the distance between object and image was larger when candle double vision test was applied. Besides vertical separated degree of diplopia was increased maximally by using synoptophore and the involved eye position was inferior than the other eye.The orbital reconstruction related surgical techniques:Subciliary incision was mostly being used for simple medial and inferior blow-outfractures and in some of severer cases of medial wall fractures and complexedfractures medial incision could be applied alone of in combination with subciliaryor coronal incisions.After exposure of the fractures the herniated soft tissues have to be relievedgently and a artificial implant will be inserted under the osteum on the fracturedsite to prevent re-herniation and increase the orbital volume.The internal fixation technique with mini-plate system could be applied to fix thereplaced orbital rim in non blow-out orbital fractures.Diagnosis and treatment of traumatic optic neuropathy:44 case of clinically diagnosed as optic nerve canal fracture were included among which 20 of them were not counted into our orbital fracture patients data. The time interval between trauma and visiting ophthalmologists were from 4 hours to 18 days and 8 hours to 19 days from trauma to surgeries. 16 right eyes were involved and 2 patients had both eye affected. 29 of them had no light perceptions and others with light perception to finger counting vision.23 case accompanied by other types of orbital fractures and 11 of these with complexed fractures types.Optic canal decompression techniques:Cranial route Optic canal decompression under the surgical microscope candecompress the optic canal by removing the superior walls of the canalcompletely and incision of optic nerve sheath could be processed to release thepressure.The medial wall of the optic canal can be decompressed by naso-endoscopictechnique in small incision.Steroid treatment regimen:All admitted patients in both steroid treatment and surgical groups will receive large dose (500mg/day) methylpredinisolone intravenously for 3-5 days. Prednisone was used for taping latterly.ResultsThe causes of orbital fractures:The major causes for orbital blowout fractures in this study were assaults (44.9%, 70/156) and motor vehicle accidents (29.5%, 46/156) and followed by accident object attach (12.3%,26/211) ,fallings(6.6%,14/211) , industrial trauma (3.3%,7/211), and others(1.9%,4/211) ;In blow-out fracture patients, the first major cause was assaults 44.9% (70/156) , then by car accidents(29.5%, 46/156), mechanic trauma 13.5% (21/156), fallings 7.1% (11/156), industrial accidents2.6% (4/156), abd others (2.6%, 4/156). But motor vehicle accidents (78.2%, 43/55) was in the first place for causing non-blowout fractures. Then the followings are the other causes: accident object attach 9.1% (5/55), fallings 5.5% (3/55), industrial accidents 5.5% (3/55) and violence 1.8% (1/55).CT scanning efficacy and the clinincal significanceBoth axial and coronal CT scanning could show the orbital fracture morphologies with corresponding features for all types of the fractures. Axial scanning is better for the medial and lateral wall fractures and the coronal views especially gave better results for inferior and superior wall fractures as well as other types like medial and complexed fractures. 3D reconstructions can gave doctors’ best impression on those non blow-out fractures with replaced orbital bones and good for diagnosis and designing surgeries.Among the whole group of 211 orbital fractures, 156 cases were blow-out fractures and rest 55 cases were non blow-out fractures. The major clinical symptom was diaplopia in 135 patients(72.2%) and enophthalmos in 103 cases (55.1%).Clinical classification and featuresThe blow-out fractures accounted for 73.93% in total cases. 44.08%(69/156)were medial wall fractures , 23.69% (37/156) for inferior and 32.23% (50/156) for medial-inferior orbital fractures.Diplopia were found in 113cases (72.44%) and 55.12% (86 cases) with enophthaimos. Among the 55case of none blow-out fractures, 24 cases were with involvement of lateral wall fractures and 8 for simple simple superior wall, naso-ethmo-orbital fractures in 7 cases, 3 with LeFortII, 2 with LeFortIII, zygomatic related fractures in 9 cases and 2 cases hard to be classified. There were 28 peadiatric orbital wall fractures (13.27%) among the 211 cases. Violence was the major cause accounting for 46.42% (13/28) . There were 11 cases of simple orbital floor fractures with 7 trapdoor type, 6 medial wall fractures, 5 medial-inferior and 6 complexed fractures. Vomitings occurred in 4 children 19%) and 3 of them were with trapdoor fractures.Superior orbital wall fractures involved with frontal sinus and upper orbital rim were found in 20 cases. In these type of fractures, enophthalmos was severer and the ocular motility disturbances were more likely related with its accompanied other major parts of the fractures. 5 children were blind due to accompanied optic canal fractures.General clinical findings in blow-out fracturesMedial wall fractures:There were 29 enophthalmos (41.46%) out of 69 patients with the difference of2.85±0.72mm comparing the contralateral eyes ; Diplopia occurred in 50.72%patients. All patients with subjective diplopia could be evaluated out for thedisturbances of extraocular muscle motilities by both red glass technique andsynoptophore .Inferiro orbital wall fractures:Among the 37 inferior wall fractures 14 cases 37.83% ) were withenophthalmmos with the difference of 2.44±0.46mm comparing the contralateral eyes ; Diplopia occurred in 26cases (70.45%).The inferior rectus muscle function alterations were found out in 39 patients wit 6 cases of involvement of inferior oblique muscles. Synoptophore was more sensitive than red glass technique in finding the inferior oblique muscles motility changes(15 out of 33 inferior rectus muscle function abnormalities accompanied by inferior oblique muscle involvement were found.).Medial-inferior orbital wall fractures:45 out of 50 cases of Medial-inferior orbital wall fracture patients had enophthalmos (90%) and the difference comparing with the contralateral eyes was 2.44±0.46mm. Diplopia occurred in. 47cases(94.00%). 82% patient could bo detected with inferior oblique muscle function alterations. The severity and incidence of enophthalmos and diplopia were higher than other two types of blow-out fractures respectively.Vision alterations and the etiologyComparing the visual acuities before and six months after wounded for all patients, the number with relatively normal visual acuities in blowout fracture patients was significant higher than that in non-blowout fracture (Mann-Whitney test, Z=-9.007, P<0.001) .Global ruptures and vitreous hemorrhage were two primary ocular injuries causing visual acuity decreased in orbital blowout fracture with incidence of 26.3%. There was no significant difference found among medial, inferior and medial-inferior wall fractures in visual injuries before and six months after wounded (Kruskal-Wallis test, P=0.641) . The incidence of blindness in orbital blowout fracture was significant lower than that in non-blowout fracture (Mann-Whitney test, Z=-8.124, P<0.001) .Traumatic optic neuropathy is the major cause for visual injuries in non-blowout fracture patients and the incidence was 69.0%. The incidence of blindness in non blowout fracture patients with optic foramen fracture was significant higher than that without optic foramen fracture (Mann-Whitney test, Z=-5.050, P<0.001) .Sub-classification of blow-out orbital fractures and related ocular motilitydisturbancesSub-classification of medial orbital fracturesAccording the sub-classification criteria defined, 30 out of 69 patients were assubtype I and 39 were subtype 2.Clinical findings in subtypes:Enophthlmos in subtype I: 80% (24/30) of the patients with enophthalmos of2.98±0.71mm difference comparing with contralateral eyes. Enophthlmos in subtype II: 12.8%(5/39) cases had enophthalmos of 2.25±0.42mm difference comparing with contralateral eyes. Comparing with subtype II, the incidence and severity of enophthalmos in subtype I patients were significantly higher than that of subtype II (Z=-6.075, P<0.05, t=3.365, P<0.05) .Diplopia in subtypes: 38.46% (10/26) patient had diplopia and most of them were crossed type. 61.53% (24/39) of subtype II had diplopia and more were on same side. Comparing type I with type II medial orbital fracture groups, the incidence of medial rectus muscle palsy was higher in the former group (Z=-4.346, P<0.05) but with lower rate of medial rectus muscle restriotion (Z=-4.382,P<0.05). Meanwhile there was no statistical difference (Z=-0.400,P>0.05) between the occurrence of simultaneous paralysis and restriction of medial rectus muscles in these two groups. Less chance of diplopia in subtype I than in subtype 2 statistically (Z=-2.187, P<0.05).Sub-classification of inferior orbital fracturesAccording the sub-classification criteria defined , 14 out of 37 patients were assubtype I and 23 were subtype 2.Clinical findings in subtypes:Enophthlmos in subtype I: 64.28% (9/14) of the patients with enophthalmos of2.58±0.4mm difference comparing with contralateral eyes.Enophthlmos in subtype II: 21.73% (5/23) cases had enophthalmos of2.10±0.24mm difference comparing with contralateral eyes.Comparing with subtype II, the incidence and severity of enophthalmos in subtype I patients were significantly higher than that of subtype II (Z=-3.141, P<0.05, t=2.873, P<0.05)Diplopia in subtypes: 71.42% (10/14) patients had diplopia and most of them were at down gaze. 69.56% (16/23) of subtype II had diplopia with up gaze in most cases. Comparing type I with type II medial orbital fracture groups, no difference was found in term of diplopia occurrence between the two subtypes (Z=-2.11 ,P>0.05). comparing type I with subtype II of inferior orbital fractures, the rate of inferior rectus muscle palsy was higher in type I than in type II (Z=-3.065, P<0.05),but with less inferior rectus muscle restriction in type I (Z=-2.740,P<0.05).There was no statistical difference (Z=-0.116, P>0.05)of simultaneous paralysis and restriction of inferior rectus muscle in these 2 subtypes.Subtypes of Medial-inferior orbital wall fracturesType IM-M : In this medial wall predominant fracture type, 68.2% (15/22) patients had enophthalmos of 2.61±0.78mm difference comparing to the contralateral eyes. And 59.1% (13/22) were with dipiopia as the result of medial rectus muscle restriction in most cases.Type IM-I type: In this inferior wall predominant fracture type, 28/30 (93.3%) patients had enophthalmos of 3.66±0.93mm difference comparing to the contralateral eyes. And 24/30cases (80.0%) were with dipiopia as the result of inferior rectus muscle restriction in most cases.The incidence and severity of enophthalmos in IM-I subtype patients was significant statistically higher than that in subtype IM-M patients. No significant difference of dipiopia occurrence was found between these two subtypes. The incidences of medial and inferior rectus muscle function disturbances between thse two subtype had no difference statistically ( (5/22, 22.7%; 8/30, 26.7%) (X~2=0.105, P=0.746; X~2=0.509, P=0.476) ).The outcome of extraocular muscle functions for the patients of blow-out orbital fractures after orbital reconstruction surgeries: Effect of orbital fractures types:After 6 months of orbital reconstruction surgeries, 92.5% of medial wall fractures patients and 91.43% and 91.67% for inferior and medial-inferior wall fractured patient respectively recovered from ocular motility disturbance with no dipiopia at primary position. The outcome of extraocular muscle functions for the patients of blow-out orbital fractures after orbital reconstruction surgeries:Effect of orbital fractures types : After 6 months of orbital reconstruction surgeries, 92.5% of medial wall fractures patients and 91.43% and 91.67% for inferior and medial-inferior wall fractured patient respectively recovered from ocular motility disturbance with no dipiopia at primary position.The effect of time interval between trauma and surgeriesFor all the 3 types of orbital blow-out fractures, surgeries done less than 3 weeks after traumas gave a better ocular mobility disturbance relieved result statistically in EOM restriction types 6 months after surgeries(P 1=0.02, P2=0.03, X~2=12.75 ,P3<0.001 for meidal, inferior and medial-inferior wall fractures). The EOM palsy patients who had significant recovered with no dipiopia at primary position before 3 weeks after trauma showed no statistically difference between these 3 types of fractures.( P4=1.00 P5=1.00, x~2=0.10 P6=0.76) The major causes for orbital blowout fractures in this study were assaults (44.9%, 70/156) and motor vehicle accidents (29.5%, 46/156) ; But motor vehicle accidents (78.2%, 43/55) was in the first place for causing non-blowout fractures.Causes for visual acuity alterationsComparing the visual acuities before and six months after wounded, the number with relatively normal visual acuities in blowout fracture patients was significant higher than that in non-blowout fracture (Mann-Whitney test, Z=-9.007, P<0.001). Scleral ruptures and vitreous hemorrhage were two primary ocular injuries causing visual injuries in orbital blowout fracture with incidence of 26.3%. There was no significant difference found among three subtypes of orbital blow(?)ut fracture in visual injuries before and six months after wounded (Kruskal-Walli(s) test, P=0.641) . The incidence of blindness in orbital blowout fracture was significant lower than that in non-blowout fracture (Mann-Whitney test, Z=-8.124, P<0.001) .Traumatic optic neuropathy is the major cause for visual injuries in non-blowout fracture patients and the incidence was 69.0%. The incidence of blindness in non blowout fracture patients with optic foramen fracture was significant higher than that without optic foramen fracture (Mann-Whitney test, Z=-5.050, P<0.001) .Effect of Optic nerve decompression surgeries and steroid treatment on the visual outcome of traumatic optic neuropathy caused by optic canal fractures:By controlling pre-treatment visual acuity, with or without orbital fractures, timeinterval between trauma and treatment and methods of treatment, the P values oflogistic regression index for the post surgery visual outcome with pre-treatmentvisual acuities, accompanied orbital fractures , and time interval between traumaand treatment are as followings: 0.78、-0.14, -0.21, 0.00, 0.39.Surgery factor (surgical group) had no statistic effect on the outcome of visualacuities. But pre-surgery visual acuity and treatment methods factor had statisticsignificance on the study model (X~2=33.07, 10.0, P=0.01、0.04) .By controlling other factors, the partial correlation coefficient of post-surgeryvisual outcome with pre-treatment visual acuities, accompanied orbital fractures ,and time interval between trauma and treatment are as followings: 0.51、-0.20、0.77、-0.01, P values are 0.01、0.36、0.00、0.97.The treatment effect of surgery and steroid treatment on visual outcomeThe effect of the pre-treatment visual acuities, with or without orbital fractures, andtime interval between trauma and treatment on the post-treatment visual acuities between these two treatment methods were statistically compared by using Kruskal-Wallis Test. The results are X~2=0.00,0.01,0.06, P=0.99,0.95,0.82,0.21. T test was used for the measurement and T=0.84 , P=0.41. St更多还原