Résumé
Background The incidence of dry eye is increasing among young adults because of wide usage of video display terminal.But the early diagnosis of dry eye still presents challenge to medical practitioners.The accurate diagnosis and treatment of the dry eye,therefore,is a topic of high interest to researchers.Previous examination outcome of dry eye is interferred primarily due to invasive procedure.It is very important to search an examination approach.Objective This study was to use Keratograph 5M,a non-invasive ocular surface analyzer to evaluate the influence of watching video display terminal on ocular surface and tear film.Methods Eighty-one eyes of 81 health volunteers among 18-30 years were enrolled in Affiliated Eye Hospital of Nanchang University from March 1,2015 to November 10,2015 under the informed consent,including 39 males and 42 females.The subjects watched the computer for continuously 3 hours under the nature light,and ocular surface related examinations were performed and compared before and after video display terminal exposure,including non-invasive tear film break-up time (NITBUT),tear meniscus height,conjunctival hyperemia scoring,limbal congestion scoring,corneal fluorescein staining scoring,meibomian gland imaging and lipid layer analysis.Results The number of eyes with visual fatigue,dryness,pain,blurring and conjunctival congestion was significantly increased after 3-hour video display terminal exposure in comparison with before (all at P＜0.01).The initial NITBUT and mean NITBUT were (6.086± 3.701) s and (9.103 ± 4.680) s,and tear meniscus height was (0.190 ± 0.032) mm after trail,which were significantly lower than (11.445 ±4.964) s,(14.626 ±4.467) s and (0.212 ±0.040) mm of before trail,respectively;The conjunctical hyperemia scoring and limbal congestion scoring were 0.869 ±0.311 and 0.572 ±0.276 after trial,which were significantly higher than 0.780 ± 0.306 and 0.509 ± 0.266 before trail,showing significant differences before and after exposure of video display terminal (all at P＜0.01).The intraocular pressure and the eye number of different scores of corneal fluorescence staining,abnormal meibomian gland and different morphological lipid layer of tear were unchanged before and after exposure of video display terminal.Conclusions Long-term exposure of video display terminal results in significant and temporary adverse influence on tear film and ocular surface.Keratograph 5M non-invasive ocular sudace analyzer can objectively assess overall ocular surface conditions.
Résumé
Background Radiation-induced optic neuropathy (RION) is a severe complication after radiotherapy for head and neck cancer,which threatens the visual acuity and quality of life of patients.Till now,there is no recognized treatment for RION.It is of great significance to study the natural progression of the RION,and to prevent and treat RION.Objective This study was to establish an ideal radioactive optic nerve injury animal model.Methods Healthy 8-week SD rats with hygiene grade were randomly divided into normal control group and model group,with 6 rats in each group.The total 30 Gy dose of radiation with 3 portions was used to irradiate the head model group rats;ELISA was performed to analysis the changes of endothelin-1 (ET-1) and Von Willebrand factor (vWF) concentrations in blood 2,4 and 8 weeks after irradiation.Hematoxylin-eosin staining and transmission electron microscope were performed to observe the changes of optic structure.The use and care of the experimental animals complied with the ARVO statement.Results The concentrations of ET-1 in the model group were (23.18± 0.11),(27.98 ±0.22),(33.90 ±0.1 1),(65.25 ±0.38) and (43.82 ± 0.09) pg/ml before irradiation,1 day,2,4,6 weeks after irradiation,those in the normal control group were (22.65 ± 0.14),(23.18 ± 0.19),(23.68 ± 0.15),(24.23±0.12) and (23.58±0.16)pg/ml.The concentrations of vWF in the model group were (63.16±2.21),(88.32± 2.06),(123.38 ± 1.36),(191.40 ± 0.61) and (141.69 ± 0.82) pg/ml before irradiation,1 day,2,4,6 weeks after irradiation,those in the normal control group were (62.82 ± 1.56),(63.35 ±2.06),(64.12 ± 1.76),(63.52±2.02) and (63.48 ± 1.55)pg/ml.There were significant differences of ET-1 and vWF concentrations among different groups and time points (ET-1:Fgroup =32.160,P =0.012;Ftime =21.180,P =0.023.vWF:Fgroup =73.110,P=0.001;Ftime =46.180,P =0.002).The nerve fiber bundles was swelled with disordered arrangement and vacuolization 8 weeks after irradiation.Axon swell and atrophy,axons with myelin sheath layer plate separation were obtained.The rates of axon demyelination in the normal control group and model group were (1.35 ±0.79) ％ and (14.44±2.32)％,respectively.There was a statistically significant difference between the two groups (t =14.07,P＜0.01).Conclusions The total 30 Gy dose of radiation on the head of rats can make stable radioactive optic nerve injury model.This model making method is simple,cheap and practical,which is worth further study.