Comparison of macular changes according to the etiology of optic neuritis:a cross-sectional study

AIM:To compare the macular structure including foveal thickness among patients with optic neuritis(ON)according to the etiology and to investigate the possible correlation between structural and visual outcomes METHODS:In this retrospective cross-sectional study,the clinical data of patients with aquaporin-4 immunoglobulin G-related ON(AQP4 group,40 eyes),myelin oligodendrocyte glycoprotein IgG-related ON(MOG group,31 eyes),and multiple sclerosis-related ON(MS group,24 eyes)were obtained.The retinal thickness of the foveal,parafoveal and perifoveal regions were measured.Visual acuity(VA),visual field index and mean deviation were measured as visual outcomes.RESULTS:The AQP4 group showed a significantly thinner fovea(226.4±13.4μm)relative to the MOG(236.8±14.0μm,P=0.015)and MS(238.9±14.3μm,P=0.007)groups.The thickness in the parafoveal area also was thinner in the AQP4 group,though the difference in perifoveal retinal thickness was not significant.Foveal thickness was correlated with VA in the AQP4 group(coefficientρ=-0.418,P=0.014),but not in the MOG and MS groups(P=0.218 and P=0.138,respectively).There was no significant correlation between foveal thickness and visual field test in all three groups.CONCLUSION:The significant thinning in the fovea and parafoveal areas in the AQP4 group compared to the MOG and MS groups are found.Additionally,macular changes in AQP4-ON show a significant correlation with VA.The results provide the possibility that retinal structural damage could reflect functional damage in AQP4-ON,distinct from MOGON and MS-ON.

Optical Fibre Communication Feature Analysis and Small Sample Fault Diagnosis Based on VMD-FE and Fuzzy Clustering

To solve the problems of a few optical fibre line fault samples and the inefficiency of manual communication optical fibre fault diagnosis,this paper proposes a communication optical fibre fault diagnosis model based on variational modal decomposition(VMD),fuzzy entropy(FE)and fuzzy clustering(FC).Firstly,based on the OTDR curve data collected in the field,VMD is used to extract the different modal components(IMF)of the original signal and calculate the fuzzy entropy(FE)values of different components to characterize the subtle differences between them.The fuzzy entropy of each curve is used as the feature vector,which in turn constructs the communication optical fibre feature vector matrix,and the fuzzy clustering algorithm is used to achieve fault diagnosis of faulty optical fibre.The VMD-FE combination can extract subtle differences in features,and the fuzzy clustering algorithm does not require sample training.The experimental results show that the model in this paper has high accuracy and is relevant to the maintenance of communication optical fibre when compared with existing feature extraction models and traditional machine learning models.

Differential Diagnosis for Multiple Sclerosis-related Optic Neuritis

Purpose:.To analyze clinical features and main causes of multiple sclerosis-related optic neuritis(MS-ON), providing evidence for the differential diagnosis of MS-ON.Methods: Clinical data were collected from 527 patients, 123 males and 404 females, diagnosed with MS-ON between June2008 and June 2013. Visual acuity, optometry, visual field,slit-lamp microscopy, indirect ophthalmoscopy(20D), optical coherence tomography(OCT) and magnetic resonance imaging(MRI) were performed. Venous blood was sampled for detection of autoimmune antibodies and Aquaporin(AQP-4).Results:.Fifty nine cases were diagnosed with neuromyelitis optica-related optic neuritis.(NMO-ON),.27 Sjogren's syndrome-related optic neuropathy,.22 tumors,.21 anterior ischemic optic neuropathy, 15 radiation-induced optic neuropathy, 14 optic neuropathy-related infection, 17 genetic eye diseases and 10 open angle glaucoma. Among168 MS-ON patients undergoing optic nerve MRI,90 cases(53.57%) had a lesion < 15 mm in size, 15-30 mm in 76(45.24%) and > 30 mm in two(1.19%).Conclusion:.MS-ON is more commonly misdiagnosed with NMO-ON and Sjogren's syndrome, when compared to optic neuropathy, tumors and ischemic optic neuropathy.

Artificial intelligence for characterization of diminutive colorectal polyps:A feasibility study comparing two computer-aided diagnosis systems

BACKGROUND Artificial intelligence(AI)has potential in the optical diagnosis of colorectal polyps.AIM To evaluate the feasibility of the real-time use of the computer-aided diagnosis system(CADx)AI for ColoRectal Polyps(AI4CRP)for the optical diagnosis of diminutive colorectal polyps and to compare the performance with CAD EYE^(TM)(Fujifilm,Tokyo,Japan).CADx influence on the optical diagnosis of an expert endoscopist was also investigated.METHODS AI4CRP was developed in-house and CAD EYE was proprietary software provided by Fujifilm.Both CADxsystems exploit convolutional neural networks.Colorectal polyps were characterized as benign or premalignant and histopathology was used as gold standard.AI4CRP provided an objective assessment of its characterization by presenting a calibrated confidence characterization value(range 0.0-1.0).A predefined cut-off value of 0.6 was set with values<0.6 indicating benign and values≥0.6 indicating premalignant colorectal polyps.Low confidence characterizations were defined as values 40%around the cut-off value of 0.6(<0.36 and>0.76).Self-critical AI4CRP’s diagnostic performances excluded low confidence characterizations.RESULTS AI4CRP use was feasible and performed on 30 patients with 51 colorectal polyps.Self-critical AI4CRP,excluding 14 low confidence characterizations[27.5%(14/51)],had a diagnostic accuracy of 89.2%,sensitivity of 89.7%,and specificity of 87.5%,which was higher compared to AI4CRP.CAD EYE had a 83.7%diagnostic accuracy,74.2%sensitivity,and 100.0%specificity.Diagnostic performances of the endoscopist alone(before AI)increased nonsignificantly after reviewing the CADx characterizations of both AI4CRP and CAD EYE(AI-assisted endoscopist).Diagnostic performances of the AI-assisted endoscopist were higher compared to both CADx-systems,except for specificity for which CAD EYE performed best.CONCLUSION Real-time use of AI4CRP was feasible.Objective confidence values provided by a CADx is novel and self-critical AI4CRP showed higher diagnostic performances compared to AI4CRP.

Bilateral retinal nerve fiber layer thickness reduction in a 9-year-old myopic boy suffering from unilateral optic neuritis:A case report

BACKGROUND In this paper,we present a 9-year-old boy who demonstrates a complex interplay between myopia progression,axial length(AL)extension,and retinal nerve fiber layer(RNFL)thickness loss in both eyes.Additionally,concurrent optic neuritis has directly impacted RNFL thickness in his right eye,and its potential indirect influence on RNFL and macular ganglion cell layer(mGCL)thickness in his left eye is also noteworthy.CASE SUMMARY A 9-year-old boy with bilateral myopia presented with diminished vision and pain in his right eye due to optic neuritis,while his left eye showed pseudopapilledema.Steroid therapy improved his vision in the right eye,and 16-mo follow-up revealed recovery without recurrence despite myopia progression.Follow-up optical coherence tomography conducted 16 mo later revealed a notable thinning of the RNFL in both eyes,especially along with a reduction in mGCL thickness in the left eye.This intricate interaction between optic neuritis,myopia,and retinal changes underscores the need for comprehensive management,highlighting potential long-term visual implications in young patients.CONCLUSION The progression of myopia and AL extension led to the loss of RNFL thickness in both eyes in a 9-year-old boy.Concurrently,optic neuritis directly affected RNFL thickness in his right eye and may indirectly play a role in the thickness of RNFL and mGCL in his left eye.

Bilateral atypical optic neuritis associated with tuberculosis in an immunocompromised patient

A 27 year-old lady,presented with sudden loss of vision in the right eve tor a week.It was followed In poor vision in the left eye alter 3 days.It involved the whole entire visual field and was associated with pain on eye movement.She was diagnosed to have miliary tuberculosis and retroviral disease 4 months ago.She was started on anti-TB since then but defaulted highly active anti-retroviral therapy(HAART).On examination.her visual acuity was no perception of light in the right eye and 6/120(pinhole 3/60) in the lelt eye.Anterior segment in both eyes was unremarkable.Funduscopy showed bilateral optic disc swelling with presence ot multiple foci of choroiditis in the peripheral retina.The vitreous and relinal vessels were normal.Chest radiography was normal.CT scan of orbit and brain revealed bilateral enhancement of the optic nerve sheath that suggest the diagnosis of bilateral atypical optic neuritis.This patient was managed with infectious disease team.She was started on HAART and anti-TB treatment was continued.She completed anti-TB treatment alter 9 months without any serious side effects.During follow up the visual acuity in both eyes was not improved.However.funduscopy showed resolving ol disc swelling and choroiditis following treatment.

Optical coherence tomography in central nervous system demyelinating diseases related optic neuritis

AIM：To compare the thickness of the peripapillary retinal nerve fiber layer（RNFL）and ganglion cell-inner plexiform layer（GCIPL）among patients with various forms of optic neuritis（ON）and to identify whether any particular parameters or their thinning pattern can be used to distinguish the type of ON.METHODS：This prospective study was conducted at the Department of Ophthalmology,Faculty of Medicine,Siriraj Hospital,Thailand,between January,2015 and December,2016.We enlisted patients over 18 years of age with history of ON and categorized patients into 4 groups：1）aquaporin 4 antibodies（AQP4-IgG）positive;2）multiple sclerosis（MS）;3）myelin oligodendrocyte glycoprotein antibodies（MOG-IgG）positive;4）idiopathic-ON patients.Healthy controls were also included during the same study period.All patients underwent complete ophthalmological examination and spectral domain optical coherence tomography（OCT）imaging to analyze RNFL and GCIPL thickness after at least 3mo since the last episode of acute ON.The generalized estimating equation（GEE）models were used to compare the data amongst ON groups. RESULTS： Among 87 previous ON eyes from 57 patients（43 AQP4-IgG＋ON,17 MS-ON,8 MOG-IgG＋ON,and 19idiopathic-ON）,mean logMAR visual acuity of AQP4-IgG＋ON,MS-ON,MOG-IgG＋ON,and idiopathic-ON groups was 0.76±0.88,0.12±0.25,0.39±0.31,and 0.75±1.08,respectively.Average,superior,and inferior RNFL were significantly reduced in AQP4-IgG＋ON,MOG-IgG＋ON and idiopathic-ON eyes,relative to those of MS-ON.Differences were not statistically significant for RNFL or GCIPL between the AQP4-IgG＋ON and MOG-IgG＋ON groups,whereas visual acuity in MOG-IgG＋ON was slightly,but not significantly,better（0.39 vs 0.76）.Although RNFL thickness in MOG-IgG＋ON was significantly reduced as compared to MS-ON,mean visual acuity and GCIPL were not different.CONCLUSION：Thinning of superior and inferior quadrants of RNFL are more commonly seen in MOG-IgG＋ON and AQP4-IgG＋ON.Long term visual acuity in MOG-IgG＋ON is often better than AQP4-IgG＋ON,whereas the structural change from OCT is comparable.

Neuroprotective effects of gypenosides in experimental autoimmune optic neuritis

AIM：To determine whether gypenosides have protective effects in experimental autoimmune optic neuritis（EAON）.METHODS：Mice were randomly divided into seven groups：control group,model group,three different density gypenosides monotherapy,methylprednisolone monotherapy,combination of gypenosides and methylprednisolone group.The control group was subcutaneously injected with oil emulsion adjuvant and all other groups were subcutaneously immunized with an emulsified mixture of myelin oligodendrocyte glycoprotein（MOG） 35-55 peptide to induce EAON.Mice in the gypenosides groups were administered injections daily with three concentrations（15 mg/kg,30 mg/kg,45 mg/kg） of gypenosides respectively.Mice in the methylprednisolone group and the combination treatment group were injected daily with methylprednisolone（20 mg/kg） or methylprednisolone（20 mg/kg） ＋ gypenosides（30 mg/kg）,respectively.After MOG immunization,visual evoked potential（VEP）,optical coherence tomography（OCT）,and histopathologic examination were performed at 14,20,30,and 40 d post-inoculation（p.i.）.All results were expressed as mean±SEM.The data were evaluated by oneway ANOVA followed by Tukey or Games-Howell test.RESULTS：Compared with the control group,p2 latency was prolonged in the model group（P=0.041）.Combination treatment can alleviated the change in VEP at 20 d p.i.（P=0.012）.Average peripapillary retinal nerve fiber layer（RNFL） thickness was reduced in the model group（P= 0.000,30d;P=0.000,40d） and gypenosides treatment remarkably diminished the degree of RNFL degenerationat 30 d and 40 d p.i（P=0.000,30d;P=0.000,40d）.The pathomorphological results showed a decrease in demyelination（P=0.020） and inflammatory reactions in the combination group compared with the model group（20d p.i.）.Gypenosides treatment also alleviated the degree of axonal loss（40d p.i.）（P=0.003）.CONCLUSION：Treatment with gypenosides exerts protective effects on retinal nerve fibers and axons in EAON.When combined with gypenosides,methylprednisolone reduces demyelination in the acute stage of EAON.

Primary Sjgren's syndrome related optic neuritis

AIM:To determine the clinical features,diagnosis and treatment of the primary Sjogren syndrome(SS)related optic neuritis.METHODS:The clinical data of 8 patients(12 eyes)with primary SS related optic neuritis were analyzed retrospectively.RESULTS:Eight of 128 consecutive patients with optic neuritis resulted from varied causes fulfilled the diagnostic criteria for the primary SS.They presented initially with the signs and symptoms of non-specific optic neuritis,and 5 patients presenting without dryness showed a chronic inflammation of submandibular gland or parotid gland,and lymphocyte infiltration was demonstrated by labial gland biopsy in 2 patients.There were serum positive titers for anti-Sjogren syndrome A(SSA)in 7 patients and anti-Sjogren syndrome B(SSB)in 8 patients.Anti-aquaporin-4(AQP4)antibody was negative in all the 8 patients.Both glucocorticoids and immunosuppressive agent were administered,and visual acuity elevated in 8 eyes(66.7%),3 patients(37.5%)recurred in the follow-up.CONCLUSION:Primary SS related optic neuritis is less common and easily misdiagnosed.The conventional therapies for optic neuritis could not control the recurrence.

Acute changes in ganglion cell layer thickness in ischemic optic neuropathy compared to optic neuritis using optical coherence tomography

AIM:To elucidate the changes of different ganglion cell layer(GCL)thinning patterns between the optic neuritis(ON)and non-arteritic anterior ischemic optic neuropathy(NAION).METHODS:A prospective,observational study was conducted to evaluate the timing of GCL changes between acute ON and NAION using optical coherence tomography.RESULTS:Thinning on optical coherence tomography in the NAION group occurs as early as 11 d after symptomatic onset of vision loss and follows an altitudinal pattern.The mean superior-inferior GCL thickness difference in the NAION cohort was clinically significant at 5.7μm in the NAION cohort compared to controls of 0.8μm(P=0.032),but not significant in the ON group compared to controls with both groups measuring 1.1μm.Global thinning was significant for the ON group compared to controls at 7.2μm(P=0.011)but not the NAION group compared to controls at 1.35μm.CONCLUSION:These findings suggest that future treatments for NAION should be given early,and possibly before 11 d in order to prevent GCL and irreversible vision loss.

Effects of minocycline on apoptosis and neuronal changes in retinal ganglion cells from experimental optic neuritis rats

BACKGROUND： Minocycline, a tetracycline derivative, is neuroprotective in models of various neurological diseases. OBJECTIVE： To investigate the effects of minocycline on retinal ganglion cells （RGCs） in rats with optic neuritis, and to compare with the effects of methylprednisolone. DESIGN, TIME AND SETTING： This neuropathology controlled study was performed at the First Affiliated Hospital, Chongqing Medical University, China in May 2007. MATERIALS： A total of 22 female Wistar rats were randomly assigned into a normal control group （n ： 5） and an experimental group （n = 17）. The experimental group was composed of a model subgroup （n = 7）, a minocycline subgroup （n = 5）, and a methylprednisolone subgroup （n = 5）. Minocycline was supplied by Sigma, USA. METHODS： Antigen homogenate made from guinea pig spinal cord and complete Freund adjuvant was used to induce autoimmune encephalomyelitis, which could induce demyelinated optic neuritis models. Rats in the minocycline subgroup were intraperitoneally injected with minocycline （45 mg/kg） daily from day 8 following autoimmunity. Rats in the methylprednisolone subgroup were intraperitoneally injected with methylprednisolone （20 mg/kg） daily from day 8 following autoimmunity. MAIN OUTCOME MEASURES： On day 18 after autoimmunily induction, pathological changes in the optic nerve were observed by hematoxylin-eosin staining. The percentage area of axons in the transverse section of the optic nerve was measured by Bielschowsky staining. Apoptosis of RGCs was detected by TUNEL. RESULTS： Under an optical microscope, the optic nerve in rats with demyelinated optic neuritis showed a vacuole-like structure of fibers, irregular swelling of the axons, and infiltration of a large quantity of inflammatory cells. With an electron microscope, the optic nerve presented with vacuole-like structures in the axons, a small percentage area of axons in the transverse section, loose myelin sheaths, and microtubules and microfilaments disappeared. The pathological changes in the optic nerve met the changes in demyelinated optic neuritis. Moreover, there was significant apoptosis of RGCs. The percentage area of optic nerve axons in the transverse section was significantly increased and the number of apoptotic RGCs was increased after treatment with methylprednisolone and minocycline. Compared with methylprednisolone, minocycline had better effects on reducing RGC apoptosis （P 〈 0.05）. CONCLUSION： Minocycline has better inhibitory effects on RGC apoptosis than methylprednisolone. Minocycline can decrease the damage to axons of demyelinated optic neuritis rats, and has similar protective effects on neurons from demyelinated optic neuritis rats as methylprednisolone.

Structural-visual functional relationships detected by optical coherence tomography in varying age-cohorts' patients with optic neuritis

AIM: To assess the relationships of final best-corrected visual acuity(BCVA) and the optic nerve structural loss in varying age-cohorts of optic neuritis(ON) patients.METHODS: This is a retrospective, cross-sectional study.Totally 130 ON subjects(200 eyes) without ON onset within 6mo were included, who underwent BCVA assessment,peripapillary retinal nerve fibre layer(pRNFL) and macular segmented layers evaluation by optical coherence tomography(OCT).RESULTS: For the 0-18y cohort, the final BCVA(logMAR)was significantly better and less frequent recurrences than adult cohorts(P=0.000). The final BCVA(logMAR) in all age-cohorts of the ON patients had negative and linear correlations to the pRNFL thicknesses and macular retinal ganglion cell layer(mRGCL) volumes, when the pRNFL thicknesses were reduced to the thresholds of 57.2-67.5 μm or 0.691-0.737 mm;in mRGCL volumes, respectively, with the strongest interdependence in the 19-40y cohort. The ON patients from varying age cohorts would be threatened by blindness when their pRNFL thicknesses dropped 36.7-48.3 μm or the mRGCL volumes dropped to 0.495-0.613 mm;.CONCLUSION: The paediatric ON has best prognosis and young adult ON exhibits perfectly linear correlations of final vision and structural loss. The pRNFL and the mRGCL could be potential structural markers to predict the vision prognosis for varying-age ON patients.

Optical diagnosis of colorectal polyps using convolutional neural networks

Colonoscopy remains the gold standard investigation for colorectal cancer screening as it offers the opportunity to both detect and resect pre-malignant and neoplastic polyps.Although technologies for image-enhanced endoscopy are widely available,optical diagnosis has not been incorporated into routine clinical practice,mainly due to significant inter-operator variability.In recent years,there has been a growing number of studies demonstrating the potential of convolutional neural networks(CNN)to enhance optical diagnosis of polyps.Data suggest that the use of CNNs might mitigate the inter-operator variability amongst endoscopists,potentially enabling a“resect and discard”or“leave in”strategy to be adopted in real-time.This would have significant financial benefits for healthcare systems,avoid unnecessary polypectomies of non-neoplastic polyps and improve the efficiency of colonoscopy.Here,we review advances in CNN for the optical diagnosis of colorectal polyps,current limitations and future directions.

Diagnosis of lacrimal punctum lesions using optical coherence tomography: a preliminary study

AIM:To study the imaging characteristics of lacrimal punctum lesion with optical coherence tomography(OCT),and provide imaging basis for the diagnosis and treatment of lacrimal punctum diseases.METHODS:A total of 25 patients(28 eyes)with epiphora and lacrimal puncta lesions were enrolled.Lacrimal puncta lesions included:punctum membrane obstruction in 7 cases(9 eyes),punctum agenesis in 1 case(1 eye),a mass protruded from the punctum in 1 case(1 eye),slit puncta in 1 case(1 eye),peri-puncta mass in 2 cases(2 eyes),chronic dacryocystitis in 4 cases(4 eyes),and primary puncta stenosis in 9 cases(10 eyes;3 eyes mild,4 eyes moderate and 3 eyes severe).All patients were examined by slit lamp microscopy and OCT to observe the morphological characteristics of abnormal punctum.RESULTS:Two types of complete membrane obstruction and incomplete membrane obstruction of puncta were observed in OCT images of 7 patients.No lacrimal punctum and lacrimal canalicular cavity were found in 1 case with punctum agenesis.OCT images showed that a narrow lumen remained in the lacrimal puncta in 1 patient with a mass protruded from the punctum.OCT of punctum in a patient with slit punctum after stent placement showed stent and abnormal lacrimal structure.No abnormal intraluminal structure was found in 2 cases of peri-puncta mass after OCT scan,and the lacunar space was narrower than that of the contralateral eye.OCT of puncta in 4 patients with chronic dacryocystitis showed that pus floated in tear with lump-like medium-low reflex.In 9 patients with primary lacrimal puncta stenosis,OCT image could clearly show the changes of puncta lumen in different degrees and shapes.CONCLUSION:OCT is feasible for the examination of pathological punctum,and can provide imaging basis for the diagnosis and treatment of punctum disease.

Role of optical spectroscopy using endogenous contrasts in clinical cancer diagnosis

Optical spectroscopy has been intensively studied for cancer management in the past two decades.This review paper first introduces the background of optical spectroscopy for cancer management,which includes the advantages of optical techniques compared to other established techniques,the principle of optical spectroscopy and the typical setup of instrumentation.Then the recent progress in optical spectroscopy for cancer diagnosis in the following organs is reviewed:the brain,breast,cervix,lung,stomach,colon,prostate and the skin.Reviewed papers were selected from the PubMed database with keywords combining the terms of individual optical spectroscopy techniques and cancers.The primary focus is on the in vivo applications of optical spectroscopy in clinical studies.Ex vivo studies are also included for some organs to highlight special applications or when there are few in vivo results in the literature.Practical considerations of applying optical spectroscopy in clinical settings such as the speed,cost,complexity of operation,accuracy and clinical value are discussed.A few commercially available clinical instruments that are based on optical spectroscopy techniques are presented.Finally several technical challenges and standard issues are discussed and firm conclusions are made.

Clinical Analysis of the Etiology of Optic Neuritis in Patients at Different Ages in China

Purpose:.To determine the etiology of optic neuritis in patients of different ages in China. Methods: Records of optic neuritis patients who were hospitalized in the Department of Neuro-ophthalmology, General PLA Hospital, Beijing, between January 1, 2011 and December 31, 2011 were retrospectively reviewed. Results:.A total of 132 patients were divided into three groups by age..The percentage of patients aged ≤16 years,.16-45 years and >45 years were 17.4% (23/132),.54.6% (72/132), and 28.0% (37/132) respectively. The distribution of etiologies differed significantly among the three groups(x2=23.2, P=0.026)..The percentage of idiopathic demyelinating optic neuritis was the highest in the 16-45 group (44.4%), and the proportion of neuromyelitis optica was the highest in the ≤16 years group. Infectious optic neuritis was more frequently seen in patients aged ≤16 years and >45 years. The source of infection was viral (n=2), nasosinusitis (n=1) and bacterial (n=1) in the ≤16 years group and neurosyphilis (n=3) and nasosinusitis (n=1) in the >45 years group. The percentage of paraneoplastic syndrome in the >45 years group was 8.11% (3/37). Conclusion:.The etiology of optic neuritis in patients at various ages differed significantly.

Change of Visual Acuity and Related Factors in Idiopathic Optic Neuritis

Purpose : To study the change of visual acuity and related factors in idiopathic optic neuritis. Methods: Retrospectively studying 136 cases (210 eyes) of idiopathic optic neuritis hospitalized in our department during last 5 years. The data was analyzed with the methods of multivariate stepwise regression analysis by SPSS statistic package. Results: The final visual acuity was very strongly related positively to the initial visual acuity at the time point of starting treatment and negatively to the time span beginning the treatment to the time showing improvement, age of patient and the duration from onset of the disorder to the time point of treatment beginning. Conclusions: Promptly right treatment can significantly change the natural course and the final vision of optic neuritis. Severe visual loss, old age, longer time without right therapy and slow improvement after the treatment may indicate an unfavorable final visual recovery. The different dosages of steroid applied in this study was not significant in view of the final visual acuity. Eye Sience 2001; 17: 46 ～ 49.

An unusual cause of optic neuritis:rickettsiosis disease

Optic neuritis(ON) may be associated to a range of autoimmune or infectious diseases.We report herein a case of ON induced by Rickettsia conorii.A 53-year-old woman presented with a recent decrease in visual acuity and headache.ON was diagnosed on the basis of ophthalmologic examination and flash visual evoked potentials.Etiological investigation made in our department eliminated first autoimmune disorders(vasculitis and connective tissue diseases).Rickettsial optic neuritis was confirmed by detection of specific antibodies in serum and the negativity of other serologic tests.An association between corticosteroids and cyclines was prescribed with improvement of visual acuity.

Optical diagnosis of colorectal polyps using high-definition i-scan: An educational experience

AIM:To examine performances regarding prediction of polyp histology using high-definition (HD) i-scan in a group of endoscopists with varying levels of experience. METHODS:We used a digital library of HD i-scan still images, comprising twin pictures (surface enhancement and tone enhancement), collected at our university hospital. We defined endoscopic features of adenomatous and non-adenomatous polyps, according to the following parameters:color, surface pattern and vascular pattern. We familiarized the participating endoscopists on optical diagnosis of colorectal polyps using a 20-min didactic training session. All endoscopists were asked to evaluate an image set of 50 colorectal polyps with regard to polyp histology. We classified the diagnoses into high confidence (i.e., cases in which the endoscopist could assign a diagnosis with certainty) and low confidence diagnoses (i.e., cases in which the endoscopist preferred to send the polyp for formal histology). Mean sensitivity, specificity and accuracy per endoscopist/image were computed and differences between groups tested using independent-samples t tests. High vs low confidence diagnoses were compared using the pairedsamples t test. RESULTS:Eleven endoscopists without previous experience on optical diagnosis evaluated a total of 550 images (396 adenomatous, 154 non-adenomatous). Mean sensitivity, specificity and accuracy for diagnosing adenomas were 79.3%, 85.7% and 81.1%, respectively. No significant differences were found between gastroenterologists and trainees regarding performances of optical diagnosis (mean accuracy 78.0%vs 82.9%,P = 0.098). Diminutive lesions were predicted with a lower mean accuracy as compared to non-diminutive lesions (74.2% vs 93.1%, P = 0.008). A total of 446 (81.1%) diagnoses were made with high confidence. High confidence diagnoses corresponded to a significantly higher mean accuracy than low confidence diagnoses (84.0% vs 64.3%, P = 0.008). A total of 319 (58.0%) images were evaluated as having excellent quality. Considering excellent quality images in conjunction with high confidence diagnosis, overall accuracy increased to 92.8%. CONCLUSION:After a single training session, endoscopists with varying levels of experience can already provide optical diagnosis with an accuracy of 84.0%.