Conjunctival Images Research Articles

Development of Automated Conjunctival Hyperemia Analysis Software

Conjunctival hyperemia is observed in a variety of ocular inflammatory conditions. The evaluation of hyperemia is indispensable for the treatment of patients with ocular inflammation. However, the major methods currently available for evaluation are based on nonquantitative and subjective methods. Therefore, we developed novel software to evaluate bulbar hyperemia quantitatively and objectively. First, we investigated whether the histamine-induced hyperemia of guinea pigs could be quantified by image analysis. Bulbar conjunctival images were taken by means of a digital camera, followed by the binarization of the images and the selection of regions of interest (ROIs) for evaluation. The ROIs were evaluated by counting the number of absolute pixel values. Pixel values peaked significantly 1 minute after histamine challenge was performed and were still increased after 5 minutes. Second, we applied the same method to antigen (ovalbumin)-induced hyperemia of sensitized guinea pigs, acquiring similar results except for the substantial upregulation in the first 5 minutes after challenge. Finally, we analyzed human bulbar hyperemia using the new software we developed especially for human usage. The new software allows the automatic calculation of pixel values once the ROIs have been selected. In our clinical trials, the percentage of blood vessel coverage of ROIs was significantly higher in the images of hyperemia caused by allergic conjunctival diseases and hyperemia induced by Bimatoprost, compared with those of healthy volunteers. We propose that this newly developed automated hyperemia analysis software will be an objective clinical tool for the evaluation of ocular hyperemia.

Vessel Extraction of Conjunctival Images Using LBPs and ANFIS

The main goal of medical imaging applications is to diagnose some diseases, try to prevent the progression of them, and actually cure the patients. The number of people that suffer from diabetes is growing very fast these recent years in many countries and it is needed to diagnose this disease in the beginning to prevent the subsequent side effects like blindness and so on. One of the first ways to detect this disease is analysis of vessels in some parts of the eye such as retina and conjunctiva. Some studies have been done on effects of vessel changes of conjunctiva in diabetes diagnosis and it is proved that conjunctival vessel extraction and analysis is a good way for this purpose. In this paper, we proposed a method to detect and extract the vessels of conjunctiva automatically. It is the first stage of the process of diabetes diagnosis. We first extract some textural features from each pixel of the conjunctiva image using LBP and then classify each pixel to vessels or nonvessels according to the features vector based on a supervised classifier, ANFIS. We tested the proposed algorithm on 40 conjunctival images to show the performance and efficiency of our method.

In Vivo Cross-Sectional Observation and Thickness Measurement of Bulbar Conjunctiva Using Optical Coherence Tomography

To observe in vivo bulbar conjunctival structures, and determine the reproducibility of thickness measurements of normal human conjunctiva through optical coherence tomography (OCT) images. The bulbar conjunctivas of three study groups were observed: five enucleated porcine eyes with 20 um thickness aluminum foils inserted beneath conjunctival stroma; five glaucoma patients with 6-0 thread placed beneath conjunctival stroma during trabeculectomy; and 18 normal subjects. The cross-sectional conjunctival images were acquired using the scanning protocol from an optical coherence tomography device (Anterior Segment 5 Line Raster scanning protocol, Cirrus HD-OCT; Carl Zeiss Meditec, Inc., Dublin, CA). The thickness of different conjunctival layers was measured using central corneal thickness measurement software in the 18 normal subjects. Two reproducible parameters-interobserver (within-subject between-examiners) and intraobserver (within-subject between-date)-were estimated with intraclass correlation coefficients (ICC). A thin hyporeflective surface layer, corresponding to the conjunctival epithelium layer, was observed. Beneath it, the conjunctival stroma appeared hyperreflective and was separated by a demarcation from the underlying progressively lower reflective Tenon's capsule. The anatomic location of the demarcation, which represents the loose connection between the conjunctival stroma and Tenon's capsule, was confirmed by inserting aluminum foil in porcine eyes, and by a 6-0 thread mark in glaucoma patients' eyes. The average conjunctival epithelium, stroma, and full thickness of the 18 normal subjects was 47.3 ± 8.4 um, 190.8 ± 47.5 um, and 238.8 ± 51.1 um, respectively. The intraobserver and interobserver intraclass correlation coefficients ranged from 0.918 to 0.985. It is possible to accurately image and measure the cross-sectional structures of the bulbar conjunctival tissue with high resolution OCT.

Evaluation of histamine-induced conjunctival oedema in guinea pigs by means of image analysis

BackgroundConjunctival oedema is commonly observed in patients with allergic conjunctivitis and can be induced by histamine. In animal models of allergic conjunctivitis, conjunctival oedema is generally evaluated by measuring the...

Image Analyses of the Kinetic Changes of Conjunctival Hyperemia in Histamine-Induced Conjunctivitis in Guinea Pigs

Conjunctival hyperemia is the most common finding in patients with allergic conjunctivitis. Histamine is a typical chemical mediator involved in allergic conjunctivitis and induces hyperemia. Here, we investigated the kinetic changes in bulbar hyperemia induced by histamine in eyedrops. Male guinea pigs were challenged with histamine in eyedrops. Bulbar conjunctival images were taken every 10 seconds by a digital camera up to 8 minutes after histamine challenge, and the software program ImageJ was used to analyze the images. Images were binarized, and a region of interest unobscured by corneal and scleral vessels was selected as the evaluation area. Evaluations were carried out before and after histamine challenge by counting the numbers of absolute pixel values, percent changes in pixels, or the fractal dimension in acquired images. After histamine challenge, the conjunctival vessel area continued to increase up to 5 minutes before stabilizing. The various parameters used to evaluate the images (numbers of absolute pixel values, percent change in pixels, or the fractal dimensions) markedly increased 1 minute after histamine challenge, gradually increased up to 5 minutes, and then gradually decreased before reaching a level that remained significantly higher than that before histamine challenge. This is the first report to quantitatively evaluate bulbar hyperemia induced by histamine using image analysis. The development of software that can automatically yield meaningful values for hyperemia from hyperemia images will be a useful objective tool in clinical trials for evaluation of drug effects in animal models and in humans.

Reliability of Grading Lissamine Green Conjunctival Staining

To assess the reliability of a lissamine green grading scale for conjunctival images. A 20-second video clip of the right eye of 288 contact lens-wearing individuals was recorded using a digital slip-lamp camera after instilling liquid lissamine green. A single nasal and temporal still image were selected. A masked reader used the Oxford grading scale to grade the images on two occasions whereas a second masked reader graded each image on 1 occasion. kappa statistics and 95% confidence intervals (CIs) were used to determine the within- and between-grader reliability overall and when the sample was stratified by age, sex, contact lens type, and disease severity. There was substantial within-grader reliability for both the nasal (kappasimple = 0.69, 95% CI, 0.63-0.75) and temporal (kappasimple = 0.73, 95% CI, 0.67-0.79) images. There was moderate between-grader reliability for both the nasal (kappasimple = 0.51, 95% CI, 0.44-0.58) and temporal (kappasimple = 0.51, 95% CI, 0.44-0.58) images. Age, sex, and contact lens type did not affect within- or between-examiner reliability. There may have been an influence of disease severity on within-examiner reliability, because grading of the temporal images was significantly less reliable in the images with more significant staining. Within- and between-grader reliability of lissamine green staining seems to be at least substantial to moderate. Because the extent of conjunctival staining may influence reliability, this should be considered when studies may include patients with significant staining.

Vascular Response of the Bulbar Conjunctiva to Diabetes and Elevated Blood Pressure

Retinovascular changes associated with diabetes have been clearly documented; changes in vessels of the conjunctiva are less well described. We examined changes in conjunctival vessel morphologic features in participants with and without diabetes. Case-control study. Fifty-three patients with diabetes (17 with type 1 diabetes, 36 with type 2 diabetes) and 60 controls (all aged 20-94 years). Digital red-free conjunctival images were captured and an automated computer algorithm was used to derive indices that describe the morphologic features of vessels of the conjunctiva. Percentage differences in vessel indices were adjusted for age, gender, blood pressure, and smoking status. Mean vessel diameter (micrometers) and vessel density (square millimeters of vessel per square centimeter of bulbar conjunctiva). A strong positive association between the duration of diabetes and overall mean vessel width was observed (P<0.001), resulting from changes in larger vessels (>80 mum in width). Conversely, the duration of diabetes showed a strong inverse association with vessel area (P<0.001) that appeared to be driven by the trend observed in smaller vessels (<40 mum in width). A 25% reduction (95% confidence interval [CI], -35% to -13%; P<0.001) in vessel density in those with type 1 diabetes and a 14% reduction (95% CI, -24% to -3%; P = 0.016) in those with type 2 diabetes, compared with controls, was observed. Mean vessel widths were 11% (95% CI, 4%-17%; P = 0.001) wider in type 1 and 5% (95% CI, 0%-10%; P = 0.073) wider in those with type 2 diabetes compared with controls. The difference in magnitude of effect for type 1 and type 2 diabetes compared with controls was explained by duration of diabetes. Grade of diabetic retinopathy and elevated blood pressure showed similar but less strong associations with vessel indices. Loss of capillaries and macrovessel dilation in the conjunctiva associated with diabetes compares with well-known vessel changes in the retina. Associations between morphologic changes in the conjunctiva and elevated blood pressure were similar but less strong; this may show that diabetic angiopathy predominates in those with both diabetes and elevated blood pressure.

Toxocaral chorio-retinitis. Treatment of early cases with photocoagulation.

<h3>Background</h3> Fabry disease (FD) is a treatable multisystem disease caused by a defect in the alpha-galactosidase gene. Ocular signs of FD, including corneal verticillata, are among the earliest diagnostic findings. Conjunctival lymphangiectasia (CL) has not previously been associated with FD. <h3>Methods</h3> We examined the eyes of a cohort of 13 adult patients, eight men and five women, with documented classic FD, all treated with enzyme replacement therapy (ERT) at the University of Alabama at Birmingham between February 2014 and April 2015. The average age was 48 years with a range of 35–55 years for men and 21–71 years for women. The mean duration of ERT was 8.4 years (men 8.9 years, women 7.6 years) with a range of 4–14 years. Classical Fabry mutations included Q283X, R227X, W236X and W277X. A high resolution Haag-Streit BQ-900 slit lamp with EyeCap imaging system was used to record conjunctival images. <h3>Results</h3> CL was observed in 11 of the 13 patients (85%) despite long-term ERT. Clinical presentations included single cysts, beaded dilatations and areas of conjunctival oedema. Lesions were located within 6 mm of the corneal limbus. Ten of the 13 subjects (77%) had Fabry-related cataracts and all 13 demonstrated bilateral corneal verticillata. Twelve of the 13 patients had evidence of dry eye, 9 of whom were symptomatic, and 10 had peripheral lymphoedema. <h3>Conclusion</h3> CL represents a common but under-recognised ocular manifestation of FD, which persists despite ERT, and is often accompanied by peripheral lymphoedema and dry eye syndrome.