| The human orbital anatomy structure and adjacent tissuesare very complicated. Traditionally orbital fractures have beentreated surgically by several clinicians from departments ofstomatology, plastic surgery, neurosurgery or rhinology as wellas ophthalmology. Ophthalmologists should pay more attentionto visual injuries involved in the patients. Very few good andreliable articles about visual injuries in orbital fracture patientswere found in literature search and some conclusions weredrawn short of supporting by clinical statistics. The patientswith orbital fractures investigated in this study were all fromthe key ophthalmological center in Changchun city, a majorlarge city in northeast China. The purpose of our paper was tofind the etiology of different types of orbital fractures and therelationships between different types of orbital fracture andvisual injuries .A retrospective review was undertaken for this study. 193patients (211 eyes) aging from 5 to 67.diagnosed with orbitalfractures between September 2002 and December 2004 at thedepartment of ophthalmology in the second clinical hospital ofJi lin University were involved with 157 males and 36 females.Comprehensive clinical examinations including slit lampmicroscope, ophthalmoscope, automated static thresholdperimerter, electroetinogram, visual evoked potential andfundus fluorescein angiograph were used to exam all patients.Computerized tomography examination including axialscanning, coronal scanning and three-dimensionalreconstruction were used to make the final diagnosis of orbitalfracture. In this paper orbital fractures were classified intoblowout fracture and non-blowout fracture respectively. Theorbital blowout fracture is further divided into orbital floorfracture, medial wall fracture and inferior and medial orbitalwall united fracture. Orbital non-blowout fractures includesuperior orbital wall fracture, external orbital wall fracture,naso-orbito-ethmoid fracture, LeFortâ…¡type fracture, LeFortâ…¢type fracture, orbito-maxillary-zygomatic fracture, opticforamen fracture accompanied complex orbital fractures. Allpatients were followed up more than six months either withmedical therapy or surgeries. The standards of commentingvisual acuities are normal, slight visual injury, low vision, andblindness. Data were analyzed with SPSS software.Mann-Whitney test was used to analyze the relationshipbetween two samples while Kruskal-Wallis was used to analyzethe relationship among multiple samples. The causes of orbital fractures in our data were motorvehicle accidents(42.2%, 89/211), assaults(33.6%, 71/211),slick substance impacted (12.3%, 26/211), falls (6.6%,14/211), industry injures (3.3%, 7/211), and other traumas(2.6%, 4/156). The etiology for orbital blowout fractures inthis study were assaults(44.9%,70/156),motor vehicleaccidents(29.5%,46/156),slick substance impacted(13.5%,21/156),falls(7.1%,11/156), industry injures(2.6%,4/156),and others(2.6%,4/156). But motor vehicle accidents( 78.2% , 43/55 ) was in the first place for causingnon-blowout fractures and then followed by slick substanceimpacted( 9.1%,5/55), falls (5.5%,3/55), industry injures(5.5%,3/55),and assaults (1.8%,1/55). Scleral ruptures and vitreous hemorrhage were twoprimary ocular traumas causing visual injuries in orbitalblowout fracture with incidence of 26.3%. Traumatic opticneuropathy is the major cause for visual injuries in non-blowoutfracture patients and the incidence rate was 69.0%. Comparing the visual acuities before and six months afterwounded,the number with relatively normal visual acuities inblowout fracture patients was significant higher than that innon-blowout fracture(Mann-Whitney test,Z=-9.007,P<0.001).From the view of eye protective mechanism,the orbitalblowout fracture was more protective than that of non-blowoutfracture. There was no significant difference found among threesubtypes of orbital blowout fracture in visual injuries beforeand six months after wounded(Kruskal-Wallis test,P=0.641).The incidence of blindness in orbital blowout fracture wassignificant lower than that in non-blowout fracture(Mann-Whitney test,Z=-8.124,P<0.001). The types oforbital related fractures causing blindness were LeFort â…¡(100%,3/3), LeFort â…¢(100%,2/2), naso-orbito-ethmoid(57.1%,4/7), external orbital wall (54.2%,13/24),orbital-maxillary-zygoma (44.4%,4/9)and superior orbitalwall(37.5%,3/8). Visual acuities of 95 patients were examined within 2weeks after injury and followed-up more than 6 months.Decreased visual acuities were found in 54 cases(56.8%)within 2 weeks after injury while only 27 cases(28.4%)6months after injury were reported. Part of patients appearedreversible visional diminution after orbital fracture withtendency of recovering. Traumatic optic neuropathy(TON)was a key factor invisual injury causing blindness in orbital fracture patients. Theincidence of vision decrease was 100%(22/22)and 11.1%(1/9)for visual loss respectively in TON without optic foramenfracture. Blindness in TON patients with optic foramenfractures was 100%(22/22). The incidence of blindness in nonblowout fracture patients with optic foramen fracture wassignificant higher than that without optic foramen fracture(Mann-Whitney test,Z=-5.050,P<0.001).The types of orbitalfactures with optic foramen fractures were external orbital wallfacture (40.9%,9/22),superior orbital wall facture(13.6%,3/22),orbital-maxillary-zygomatic facture(13.6%,3/22),medial orbital wall facture(9.1%,2/22),LeFortâ…¡(9.1%,2/22)and LeFort â…¢(9.1%,2/22)facture, naso-orbito-ethmoid(4.5%,1/22)facture. In conclusion, assault was the primacy causative factorcausing orbital blowout fracture and motor vehicle accidentwas the major factor causing orbital non-blowout fracture inthis series of patients. The incidence of patents with normalvisual acuities in orbital blowout fracture group was significanthigher than that in orbital non-blowout fracture. Part of patientsappeared with character of reversible visual acuity decreaseafter orbital fracture. Scleral rupture and vitreous hemorrhagewere two primary eyeball injury types causing visual decreasein orbital blowout fracture and the traumatic optic neuropathywas the key cause for inducing visual loss in non-blowoutfracture group. The incidence of blindness in orbital blowoutfracture was significant lower than that in non-blowout fracture.No significant difference was found among three subtypes oforbital blowout fracture in terms of visual injuries. Theincidence of blindness in patients with optic foramen fracturerelated orbital fracture was significant higher than that withoutoptic foramen fracture. External orbital wall fracture was themajor type causing optic foramen fracture in this group ofpatients.
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