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

Division of Optometry and Visual Science, City University London, Londinium, England, United Kingdom
Ophthalmology (Impact Factor: 6.14). 10/2005; 112(10):1801-8. DOI: 10.1016/j.ophtha.2005.04.030
Source: PubMed


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.

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Available from: Tim Ellis, Oct 13, 2014
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    • "For example, Chen et al. [3] first used image processing algorithms to study conjunctival vessels. Owen and colleagues employed an algorithm for the detection of conjunctival vessels and the quantification of their changes in diabetic patients [4] [5]. In another study, Fukushima and Tomita utilised a computer algorithm to study the changes induced by the histamine challenge of the conjunctiva in guinea pigs [6]. "
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    ABSTRACT: To investigate the distribution of different-sized vessels in the digital images of the ocular surface, an endeavor which may provide useful information for future studies. This study included 295 healthy individuals. From each participant, four digital photographs of the superior and inferior conjunctivae of both eyes, with a fixed succession of photography (right upper, right lower, left upper, left lower), were taken with a slit lamp mounted camera. Photographs were then analyzed by a previously described algorithm for vessel detection in the digital images. The area (of the image) occupied by vessels (AOV) of different sizes was measured. Height, weight, fasting blood sugar (FBS) and hemoglobin levels were also measured and the relationship between these parameters and the AOV was investigated. These findings indicated a statistically significant difference in the distribution of the AOV among the four conjunctival areas. No significant correlations were noted between the AOV of each conjunctival area and the different demographic and biometric factors. Medium-sized vessels were the most abundant vessels in the photographs of the four investigated conjunctival areas. The AOV of the different sizes of vessels follows a normal distribution curve in the four areas of the conjunctiva. The distribution of the vessels in successive photographs changes in a specific manner, with the mean AOV becoming larger as the photos were taken from the right upper to the left lower area. The AOV of vessel sizes has a normal distribution curve and medium-sized vessels occupy the largest area of the photograph.
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    • "It does not need so advanced and expensive photography devices. Authors in [8] proved that vessel analysis of conjunctiva can detect some diseases like diabetes as well as retinal vessel analysis. They claimed tortuosity of vessels change during the disease (diabetes), and it can be a useful way to early detection of diabetes. "
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    ABSTRACT: 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.
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    ABSTRACT: To evaluate the relation between the capillary drop out in perilimbal area and the stage of diabetic retinopathy using the new approach of digital fluorescein angiography and digital image analysis technology. Anterior and posterior segment fluorescein angiography were performed in 100 diabetic participants (43 males and 57 females, mean age +/- SD was 60 +/- 10.9 years) and 81 healthy persons as control group (41 males and 40 females, mean age +/- SD was 60.8 +/- 16.7 years). The loss in perilimbal capillary was estimated objectively by measuring the perilimbal intercapillary area (PIA). A significant loss in the perilimbal capillary density was observed in all stages of diabetic retinopathy (P < 0.05). 31.7 +/- 18% increase in perilimbal intercapillary area in average due to diabetes comparing to the control group, was observed. The perilimbal capillary area drops and ischemic changes associated with diabetic retinopathies showed strong correspondence.
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