Comparison of Blue and Green Confocal Scanning Laser Ophthalmoscope Imaging to Detect Retinal Nerve Fiber Layer Defects

PURPOSE: We detected retinal nerve fiber layer (RNFL) defects using a confocal scanning laser ophthalmoscopy (CSLO) with both blue and green laser sources and evaluated image quality based on laser wavelength. METHODS: This was a retrospective observational case study. Blue and green CSLO images of 181 eyes with suspected glaucoma were evaluated and compared. Three independent observers identified the presence of RNFL defects and determined which CSLO imaging source provided superior visibility of the defect. After assessing the defect imaging by laser source, demographics and image quality indices of optical coherence tomography between blue better and green better groups were analyzed. RESULTS: Both blue and green CSLO showed high discriminating ability for RNFL defects. The discriminating ability of blue CSLO was significantly greater than that of green CSLO (p = 0.004). Among eyes with a detectable RNFL defect, 61.8% were better visualized with the blue laser compared to the green laser. Compared with the blue better group, the green better group was significantly older (p = 0.009), had a greater proportion of females (p = 0.005), had poorer best-corrected visual acuity (p = 0.001), more severe cataracts (p = 0.001), lower signal strength (p = 0.003), and poor image quality indices (p = 0.001). CONCLUSIONS: Both blue and green CSLO imaging was useful for detecting RNFL defects, but blue CSLO was superior to green CSLO in quality of RNFL defect imaging in most patients with clear media.

Diagnostic performance of confocal scanning laser ophthalmoscope imaging and compared with color fundus camera in retinal pigment epithelial detachment of polypoidal choroidal vasculopathy / 中华眼底病杂志

Objective To observe confocal scanning laser ophthalmoscope (cSLO) based retinal imaging and color fundus camera in pigment epithelial detachment (PED) of polypoidal choroidal vasculopathy (PCV).Methods PED of 30 patients (32 eyes) were recruited from June 2016 to June 2017 in the Beijing Tongren Hospital who were detected in high-definition OCT (HD-OCT) and diagnosed as PCV by FFA and ICGA.There were 16 males (17 eyes) and 14 females (15 eyes);aged from 50-83 years,with the mean age of 66.59 years.The photographs of ocular fundus including color fundus camera,cSLO imaging,HD-OCT,FFA and ICGA were analyzed.Multimodal imaging results were regarded as gold standard.Sensitivity and specificity were calculated in serous and hemorrhagic PED diagnosis using color fundus camera and cSLO imaging.The positive number of PED was used to compare between two modes fundus imaging by using x2 test.Results Twenty serous PED eyes,3 hemorrhagic PED eyes and 9 serous/hemorrhagic PED eyes were determined using multimodal imaging.The sensitivity and specificity of color fundus camera were 45％ and 100％ in detecting serous PED and 100％ and 91％ in detecting hemorrhagic PED.The sensitivity and specificity of cSLO imaging were 83％ and 100％ in detecting serous PED and 50％ and 86％ in detecting hemorrhagic PED.The positive number of serous PED in cSLO imaging was significantly higher than color fundus camera (x2=7.752,P=0.011).The positive number of hemorrhagic PED in cSLO imaging shows no obvious difference compared with color fundus camera (x2=1.164,P=0.419).Conclusion The sensitivity and positive number of detecting serous PED with PCV in cSLO fundus imaging were higher than the color fundus camera technology.

Detection of drusen in patients with age-related macular degeneration by retro-mode imaging of F-10 confocal scanning laser ophthalmoscopy / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To discuss the application value of retro-mode imaging by F-10 confocal scanning laser ophthalmoscope (cSLO) for detecting drusen in patients with age-related macular degeneration (AMD).METHODS:This was a retrospective case study.During the period of October 2015 to December 2016, 67 patients with unilateral AMD (67 affected eyes and 67 fellow eyes) were included in this study.All patients underwent color fundus photography, optical coherence tomography (OCT) and retro-mode imaging by F-10 cSLO.The features of drusen by color fundus photography, OCT and retro-mode imaging were comparatively observed in the affected eyes of patients with unilateral AMD.Positive numbers of drusen in the fellow eyes of patients with unilateral AMD detected by color fundus photography, OCT and retro-mode imaging were calculated and compared.RESULTS:Retro-mode imaging by F-10 cSLO gave easier to identify images of drusen than color fundus photography and OCT in the affected eyes of patients with unilateral AMD.In the fellow eyes of 67 patients with unilateral AMD, retro-mode imaging showed drusen in 56 cases(84%), color funds photography showed drusen in 36 cases(54%), OCT showed drusen in 48 cases(72%), the difference was statistically significant(χ2=14.31, P0.0125).CONCLUSION:Retro-mode imaging by F-10 cSLO provides a non-invasive technique and should be useful for detecting and monitoring drusen in AMD.

Imaging performance and quantitative analysis of confocal scanning laser ophthalmoscope for cystoid macular edema / 中华实验眼科杂志

Background Cystoid macular edema (CME) is caused by many fundus diseases.The noninvasive clinical diagnosis methods for CME are conventional color fundus photography up to now.However,these images can not display the CME range well.Confocal scanning laser ophthalmoscope (cSLO) based retinal imaging can provide clear picture with high contrast.However,whether cSLO imaging is feasible in the quantitative assessment of CME remains unclear.Objective This study was to image the boundary of CME and assess the quantification of CME image from cSLO imaging technology.Methods A series case-observational study was designed.This study protocal was approved by Ethic Committee of Beijing Tongren Hospital.cSLO based retinal imaging technology was carried out on consecutive 24 eyes of 24 patients with clinically diagnosed and OCT confirmed CME in Beijing Tongren Eye Center from August to December 2015 under the informed consent of each individual.The radial scan range was 45°× 45 ° and the line scan level was 49 at macula area.The pseudocolar image,green light reflective image (532 nm) and infrared reflective image (785 nm) were collected.The imaging was analyzed by EasyScan software (version 1.2.2).Fundus color photography and SD-OCT were carried out in each patient.The images were graded by specialists according to the SD-OCT cross sectional results.Results The primary causes of CME included epiretinal membrane (10 eyes),branch retinal vein occlusion (BRVO) (6 eyes),central retinal vein occlusion (CRVO) (4 eyes),diabetic retinopathy (DR) (3 eyes) and CRVO with BRVO (1 eye).A CME image was exhibited on the fundus color photogram with the obscure boundary;while the clear range of CME was displayed by the cSLO imaging.The mean score of CME from pseudocolar image,green light reflective image and infrared reflective image was 3.21±0.78,2.67±0.96 and 2.54±0.83,respectively,which was significantly higher than 1.33±0.82 from the fundus color photography (all at P＜0.01).Conclusions In CME patients,the imaging quality from cSLO-based retinal imaging technology is better than that from traditional fundus color photography.Combined with SD-OCT sectional scan analysis,cSLO-based retinal imaging technology may offer a method to observe and record more fundus details for CME diagnosis.

Characteristics of fundus autofluorscence in patients with atrophic age-related macular degeneration / 中华实验眼科杂志

Background The early diagnosis and treatment is vital for the age-related macular degeneration (AMD).Previous examining methods were fundus fluorescein angiography(FFA)and optical coherence tomography (OCT).However,a new diagnostic technique,fundus autofluorescence(FAF),is applying in ophthalmology.objective This study was to observe the FAF characteristics of atrophic AMD. Methods Thirty-nine eyes of 28 patients with atrophic AMD were diagnosed and collected in our hospital and classified based on the criteria of Chen Song.FAF was performed by a confocal scanning laser ophthalmoscope(Heidelberg Retina Angiograph 2,HRA2).Characteristics of FAF images were compared with FFA images or color fundus photographs.Written informed consent was obtained from each patient prior to the examination. Results Areas with abnormal increased or decreased FAF signals were consisted or unconsisted with funduscopically visible alterations.Seven manifestations of FAF were found in the eyes with preatrophic stage of atrophic AMD,including slight change,focal increase pattern,patchy pattern,linear pattern,lacelike pattern,reticular pattern,and speckled pattern.In atrophic stage of atrophic AMD,geographic atrophy showed a well-defined hypoautofluorescence area;while non-geographic atrophy showed a ill-defined hypoautofluorescence area.There were three abnormal FAF patterns(focal,band and diffuse)in the junctional zone of geographic atrophy and diffuse pattern in the junctional zone of non-geographic atrophy. Conclusion FAF imaging is helpful for the diagnosis of atrophic AMD as a new non-invasive technique.

Quantitative evaluation of experimental choroidal neovascularization by confocal scanning laser ophthalmoscopy: fluorescein angiogram parallels heparan sulfate proteoglycan expression

The objective of the present study was to develop a quantitative method to evaluate laser-induced choroidal neovascularization (CNV) in a rat model using Heidelberg Retina Angiograph 2 (HRA2) imaging. The expression of two heparan sulfate proteoglycans (HSPG) related to inflammation and angiogenesis was also investigated. CNV lesions were induced with argon laser in 21 heterozygous Zucker rats and after three weeks a fluorescein angiogram and autofluorescence exams were performed using HRA2. The area and greatest linear dimension were measured by two observers not aware of the protocol. Bland-Altman plots showed agreement between the observers, suggesting that the technique was reproducible. After fluorescein angiogram, HSPG (perlecan and syndecan-4) were analyzed by real-time RT-PCR and immunohistochemistry. There was a significant increase in the expression of perlecan and syndecan-4 (P < 0.0001) in retinas bearing CNV lesions compared to control retinas. The expression of these two HSPG increased with increasing CNV area. Immunohistochemistry demonstrated that the rat retina damaged with laser shots presented increased expression of perlecan and syndecan-4. Moreover, we observed that the overexpression occurred in the outer layer of the retina, which is related to choroidal damage. It was possible to develop a standardized quantitative method to evaluate CNV in a rat model using HRA2. In addition, we presented data indicating that the expression of HSPG parallels the area of CNV lesion. The understanding of these events offers opportunities for studies of new therapeutic interventions targeting these HSPG.

Influence of Diabetes Mellitus on the Morphometric Analysis of the Optic Nerve Head

To evaluate the influence of diabetes mellitus (DM)on the optic nerve head topographic parameters, each group of 101 patients with open-angle glaucoma (OAG)and 91 control subjects was divided into two subgroups according to the presence or absence of DM.We compared the optic nerve head topographic parameters among groups using Topographic Scanning System (TopSSTM software version 2.2, LDT, Inc., U.S.A.);53 nonglaucomatous eyes without DM (normal group), 38 nonglaucomatous eyes with DM, 67 OAG eyes without DM, and 34 OAG eyes with DM. In the group with OAG without DM, mean contour depth, cup shape, neuroretinal rim area (NRRA), NRRA/disc area were significantly smaller but, effective area and cup/disc area were signifcantly larger than normal group (p<0.05, Student t-test).In nonglaucomatous group, the presence of diabetes showed statistically significant decrease in mean contour depth, cup shape, NRRA, NRRA/disc area ratio (p<0.05).It also showed increase in effective area and cup/disc ratio (p<0.05).These changes were similar to those reported for glaucomatous optic nerve damage.In the group with OAG, the presence of diabetes did not show statistically significant differences in the optic nerve head topographic parameters. In this study, we tried to measure the diabetic changes of the optic nerve head quantitatively using the confocal scanning laser ophthalmoscope (TopSSTM). These results suggest that the diabetic changes should be considered in the evaluation of the optic nerve head parameters for the screening or early diagnosis of open-angle glaucoma when using TopSSTM.

Diagnostic Criteria, Its Sensitivity, and Specificity with the Confocal Scanning Laser Ophthalmoscope TopSSTM

This study was conducted to establish glaucomatous diagnostic criteria and to investigate its sensitivity and specificity with the confocal scanning laser ophthalmoscope(TopSSTM) on the basis of the normal values of the optic disc parameters in previous study. Abnormal ratio of optic disc parameters were analysed in 80 primary open angle glaucoma eyes - the subjects were divided into three groups according to visual field defects, each group of mild, moderate, and severe. and then glaucomatous diagnostic critera was established. According to this diagnostic criteria, we calculated its sensitivity and specificity. We established the glaucomatous diagnostic criteria with high sensitive five parameters(1/2 depth area, C/D ratio, neuroretinal rim area(NRRA), volume above, and notching), the established criteria are 1) If NRRA is decreased, one of the four parameters is abnormal. 2) If NRRA is normal, notching and one of the other three parameters are abnormal. Notching was defined as decreased neuroretinal area at either 6 o/c or 12 o/c sector. With this criteria, the sensitivity was 89.7% in mild group and 100% in moderate and severe groups and the specificity was 89.1% in normal groups. This criteria showed high sensitivity and specificity in the diagnosis of glaucoma, so as to be useful in the early detection of glaucomatous spticdisc changes.

Relationship between Optic Disc Parameters and Myopic Refractive Errors in Myopia

Myopic discs(range: -0.5D) which were taken a confocal scanning laser ophthalmoscope(HRT, Heidelberg Engineering) were analyzed to determine the relationship between optic disc parameters and myopic refractive errors. Regression analysis and coefficient variation were used for a statistic tool. The disc area was not correlated with the myopic refractive error(p=0.21) and showed 16.0% of coefficient of variation. Cup area, cup disc area ratio, rim area, cup volume, rim volume, mean cup depth, maximum cup depth and cup shape measure showed statistically significant correlation with myopic refractive error, respectively(p<0.05). Among these parameters, rim area varied least(within all myopic eyes) with 16.5% of coefficient of variation. As the rim area is the most stable optic disc parameter interindividually in myopic population, it seem to be valuable for follow-up evaluation when a glaucomatous damage is suspected in myopic eyes by calculating its expected normal value with a regression equation.

Relationship between Optic Disc Parameters and Myopic Refractive Errors in Myopia

Myopic discs(range: -0.5D) which were taken a confocal scanning laser ophthalmoscope(HRT, Heidelberg Engineering) were analyzed to determine the relationship between optic disc parameters and myopic refractive errors. Regression analysis and coefficient variation were used for a statistic tool. The disc area was not correlated with the myopic refractive error(p=0.21) and showed 16.0% of coefficient of variation. Cup area, cup disc area ratio, rim area, cup volume, rim volume, mean cup depth, maximum cup depth and cup shape measure showed statistically significant correlation with myopic refractive error, respectively(p<0.05). Among these parameters, rim area varied least(within all myopic eyes) with 16.5% of coefficient of variation. As the rim area is the most stable optic disc parameter interindividually in myopic population, it seem to be valuable for follow-up evaluation when a glaucomatous damage is suspected in myopic eyes by calculating its expected normal value with a regression equation.

Criteria to Determine the Relevance of the Changes of Disc Parameter to the Progress of the Disease

The purpose of this study is to establish the criteria to discriminate whether the difference of the optic disc parameters compared actually reflects the progress of the disease or it is merely caused by the intraexaminer or interexaminer error. Using the confocal scanning laser ophthalmoscope (TopSS), one eye of each of 20 healthy adults were exmained by the same examiner and one eye of each of 10 adults were examined by different examiners for two consecutive days. The results out of these repeated examinations were analysed to obtain 95%confidence intervals by analysis of the change of the 12 optic disc parameters, and to determine whether the results have been influenced by the disc size or the disc tilt. The criteria to differentiate actual progression of disease from potential errors of the test were obtained. In addition, it was confirmed that changes in the parameters were not influenced by the disc size or the contour tilt. In conclusion,the outcomes of this study can be utilized as a guiding criteria when judging the relevance of the parameter changes to the progress of the disease.

Optic Disc Measurements with Topographic Scanning System

Quantitative analysis of the optic nerve head topography is important in diagnosis, differential diagnosis and follow-up of optic nerve diseases, especially in glaucoma. This study was undertaken to analyze the optic nerve head with confocal scanning laser ophthalmoscope(TopSSTM Software Version 2.2, LDT.Inc) and further to determine gender, age, refractive error and axial length-based on differences in the size and topography of the optic disc. One hundred normal human optic nerve heads of 100 subjects (42 men, 58 women, mean age 43.3+/-14.5 years) were evaluated. The men value of the parameters in TopSSTM were as follows : horizontal disc diameter 1.62+/-0.17mm, vertical disc diameter 1.77+/-0.24mm average disc diameter 1.71+/-0.15mm, disc area 2.31+/-0.43 mm2, cup area 1.01+/-0.50 mm2, horizontal cup to disc ratio 0.52+/-0.17, vertical cup to disc ratio 0.47+/-0.20, average cup to disc ratio 0.45+/-0.18, rim area 1.30+/-0.35 mm2. There were no significant correlations between these morphometric optic disc parameters and age, refractive error or axial length(p>0.05). However, male subjects had about 10% larger optic discs compared with female subjects. The optic disc size was well correlated with cup area and rim area (p<0.05).

The Normal Values of Optic Disc Parameters According to the Optic Disc Size

We analysed the optic nerve head of 151 normal eyes with 8 confocal scanning laser ophthalmoscope (TopSSTM, Laser Diagnostic Technologies, Inc.), and obtained the normal values of each parameters. As the optic disc size increases, the cup shape, effective area, 1/2 depth area, C/D ratio, neuroretinal rim area, volume above, volume below, and 1/2 depth volume also increase. Therefore we obtained the normal values of these parameters according to the optic disc size. The entire subjects were divided into four groups according to the disc area, each group of 1. 5mm2-2.0mm2, 2.0mm2-2.5mm2, 2.5mm2-3.0mm2, and 3.0mm2-3.5mm2`, respectively. The normal values of other parameters such as contour variation, rnean contour depth, average depth, maximum depth, average slope, and maximum slope which are not affected by optic disc size were obtained without grouping. This may minimize the error in evaluating the optic disc parameters and may be useful in the early detection of glaucomatous optic disc changes.

The Effect of Optic Disc Size or Age on Evaluation of Optic Disc Parameters

It has been reported that the number of optic nerve fibers decrease with age, and the C/D ratio increases as the optic disc size increases. Consequently, the normal values of the optic disc parameters measured by an optic disc analyser may change according to the optic disc size or age. We attempted to investigate the effect of individual variations in optic disc size or age on interpretation of optic disc parameters. Topographic disc parameters of 104 normal subjects aged 40 to 69 were measured using a confocal scanning laser ophthalmoscope (TopSSTM , Laser Diagnostic Technologies, Inc.). Fourteen parameters were evaluated according to the optic disc size or age. Statistical analysis was done by regression analysis. With an increase in optic disc size, the increase in cup shape, effective area, 1/2 depth area, C/D ratio, neuroretinal rim area, volume above, volume below, and 1/2 depth volume were statistically significant (p0.1). Age did not show any statistically significant influence on optic disc parameters (p>0.1). In conclusion, optic disc size, but not age, should be considered in the interpretation of optic disc parameters.