Eyes Of Diabetic Patients Research Articles

Corneal Endothelium in Patients with Diabetes Mellitus: A Historical Cohort Study

Retinopathy is the major cause of ocular morbidity in patients with diabetes mellitus. Chronic hyperglycemia spares no organ and can affect the morphology and function of the various corneal layers, compromising its transparency. This study was conducted to associate the status of corneal endothelium to diabetes mellitus (DM) and identify risk factors of compromised corneal endothelium. A total of 220 eyes of randomly selected patients (110 diabetic and 110 nondiabetic) were subjected to detailed slitlamp and fundus evaluation. Corneal endothelial status was evaluated using the Nidek Confoscan 2. Cell density, percentage polymegathism, and pleomorphism were calculated. The findings in diabetic patients were compared to those without disease. The outcome was correlated to diabetic retinopathy (DR). The effects of hypertension, hyperlipidemia, age, gender, type, duration, glycemic control, and grades of DR was also considered. The mean corneal endothelial cell density was -175 cells/mm2 (95% CI -317 to -33 cells/mm2) less in eyes of diabetic patients. The number of endothelial cells with polymegathism was significantly greater among eyes of diabetic patients. There were less corneal endothelial cells with pleomorphism in nondiabetic patients. Polymegathism and pleomorphism of corneal endothelial cells seems to be positively associated with DM type II. Cell density was significantly lower in eyes with DR than those without DR. Corneal endothelium in diabetic patients seems to be compromised. Evaluation of corneal endothelium should be part of protocol for eye care of diabetic patients.

Enzymatic Vitreolysis

In the absence of posterior vitreous detachment, vitreous cortex is adhered to the internal limiting lamina of the inner retina. This junction between the vitreous and the retina is thought to participate in the pathophysiology of diverse retinal diseases, including proliferative diabetic retinopathy and diabetic macular edema. Vitrectomy has been associated with decrease of macular edema and improvement of visual acuity in eyes of diabetic patients. Thus, many pharmacologic agents have been studied with the aim of inducing a posterior vitreous detachment in order to facilitate the surgical procedure and reduce complications of vitrectomy. More recently, different agents such as plasmin and microplasmin have shown to be able to induce a posterior vitreous detachment given as a single intravitreal injection. The aim of this article is to give a scope about the pharmacologic vitreolysis and posterior vitreous detachment studies and describe some ongoing clinical trials that will determine the efficacy and safety of these novel therapies for diabetic retinopathy.

Specificity and sensitivity of Heidelberg retina tomograph macular edema maps and the effect of exudate and hemorrhage

Abstract Purpose To assess the specificity and sensitivity of the Macular Edema Module (MEM) of the Heidelberg Retina Tomograph (HRT, Heidelberg Engineering, Heidelberg, Germany) versus Stereoscopic Color Fundus Photographs (SCFP) for patients with different grades of diabetic macular edema (ME) and non‐diabetic subjects. The effect of local exudates and hemorrhage on the specificity and sensitivity of MEM was also investigated. Methods The study included 20 eyes of 20 normal subjects without diabetes and 60 eyes of 60 diabetic patients. Eyes of diabetic patients were classified as without ME (n = 20), with questionable ME (n =20) and with Clinically Significant Macular Edema (CSME, n =20). All participants underwent a full ophthalmological evaluation, plus SCFP and HRT II MEM assessment. The sectors with exudate and/or hemorrhage on the SCFP were removed from the CSME group to generate a modified group (n=20) with CSME and without exudate or hemorrhage. Results In the normal subject group, the specificity of MEM was 92.2%. In the diabetes without macular edema group, the specificity of MEM was 91.7%. In the questionable ME group, the specificity of MEM was 93.1%. In the CSME group, the specificity of MEM was 87.3%, and the sensitivity for detecting CSME was 77.1%. In the modified group with CSME and without exudate or hemorrhage, the specificity of MEM was 85.7% and the sensitivity for detecting CSME was 96.9%. Conclusion The determination of diabetic macular edema by MEM shows good to moderate sensitivity and very good specificity. Furthermore, removing the influence of the exudate and/or hemorrhage resulted in excellent sensitivity and very good specificity.

Lower Somatostatin Expression Is an Early Event in Diabetic Retinopathy and Is Associated With Retinal Neurodegeneration

To test the hypothesis that a reduction of somatostatin (SST) in the retina exists in patients without clinically detectable diabetic retinopathy and that it is associated with retinal neurodegeneration. Human diabetic postmortem eyes (n = 10) without clinically detectable retinopathy were compared with eyes (n = 10) from nondiabetic donors. SST mRNA (RT-PCR) and SST-28 immunoreactivity (confocal laser) were measured separately in neuroretina and retinal pigment epithelium (RPE). In addition, SST-28 (radioimmunoassay) was measured in the vitreous fluid. Glial fibrillar acidic protein (GFAP) was assessed by immunofluorescence and Western blot. Apoptotic cells were quantified using transferase-mediated dUTP nick-end labeling. A higher expression of SST was detected in RPE than neuroretina in both groups. SST mRNA levels and SST-28 immunoreactivity were significantly lower in both RPE and the neuroretina from diabetic donors compared with nondiabetic donors. These results were in agreement with those obtained by measuring SST-28 in the vitreous fluid of the same donors. Increased GFAP and a higher degree of apoptosis were observed in diabetic retinas compared with nondiabetic retinas. These changes were most evident in patients with the higher deficit of SST. Underproduction of SST is an early event in the eyes of diabetic patients and is associated with glial activation and neural death. In addition, our results suggest that RPE is an important source of SST in the human eye. The possible role of the lower production of SST in the pathogenesis of diabetic retinopathy requires further investigation.

The correlation between optical coherence tomographic features and severity of retinopathy, macular thickness and visual acuity in diabetic macular edema

To investigate the correlation between the features of optical coherence tomography (OCT) and the severity of concurrent retinopathy, central macular thickness (CMT), and best-corrected visual acuity in clinically significant diabetic macular edema. In a prospective study, OCT was performed in 55 eyes of 55 patients with clinically significant diabetic macular edema, in 58 eyes of 30 patients with diabetes without retinopathy, and in 40 eyes of 21 healthy control subjects. The OCT features were categorized into: type 1, sponge-like retinal swelling; type 2, cystoid macular edema; type 3, serous retinal detachment; and type 4, vitreofoveal traction. The CMT in eyes with diabetic macular edema was significantly higher than in eyes of healthy controls or in eyes of diabetic patients without retinopathy (P < 0.001). Visual acuity correlated with CMT in diabetic macular edema (r = 0.558, P < 0.001). The prevalence of OCT type 1 was significantly higher in eyes with mild-to-moderate non-proliferative retinopathy (NPDR) than in eyes with severe NPDR to proliferative retinopathy (PDR) (P = 0.0069). The prevalence of OCT types 3 and 4 was significantly higher in eyes with severe NPDR to PDR than in eyes with mild-to-moderate NPDR (P = 0.0056). OCT type 1 showed the least CMT (P < 0.001) and the best visual acuity (P = 0.002). There was a significant correlation between OCT patterns of clinically significant diabetic macular edema and severity of retinopathy, CMT, and visual acuity.

Feasibility Study on Computer-Aided Screening for Diabetic Retinopathy

To conduct a feasibility study of computer-aided screening for diabetic retinopathy by developing a computerized program to automatically detect retinal changes from digital retinal images. The study was carried out in three steps. Step 1 was to collect baseline retinal image data of 600 eyes of normal subjects with normal fundi and data of 300 eyes of diabetic patients with diabetic retinopathy. All data were recorded by digital fundus camera. Step 2 was to analyse all retinal images for normal and abnormal features. By this method, the automated computerized screening program was developed. The program preprocesses colour retinal images and recognizes the main retinal components (optic disc, fovea, and blood vessels) and diabetic features such as exudates, haemorrhages, and microaneurysms. All of the accumulated information is interpreted as normal, abnormal, or unknown. Step 3 was to evaluate the sensitivity and specificity of the computerized screening program by testing the program on diabetic patients and comparing the program's results with the results of screening by retinal specialists. Diabetic patients (182 patients, 336 eyes) were examined by retinal specialists; 221 eyes had a normal fundus and 115 eyes had nonproliferative diabetic retinopathy. Digital retinal images were taken of these 336 eyes and interpreted by the automated screening program. The program had a sensitivity and specificity of 74.8% and 82.7%, respectively. The automated screening program was able to differentiate between the normal fundus and the diabetic retinopathy fundus. The program may be beneficial for use in screening for diabetic retinopathy. Further development of the program may provide higher sensitivity.

Dry eye in diabetic patients

To compare the prevalence of keratoconjunctivitis sicca (KCS) in a prospective cohort of 22,382 diabetic patients with that in the general population. Prospective, observational, cohort study. A district of israel's largest health maintenance organization. We followed the electronic medical records of all patients in the district older than 50 years (159,634 patients) between January 1 and December 31, 2003. Of those, 22,382 (14.0%) had diabetes. The proportion of ocular lubrication consumers was compared among diabetic and nondiabetic patients. All HbA1c laboratory tests performed by the diabetic patients were documented (41,910 tests), and glycemic control was correlated with the consumption of ocular lubrication. Ocular lubrication use by diabetic patients compared with the general population and the relationship between glycemic control and ocular lubrication use. After age and gender adjustment, a significantly higher percentage of diabetic patients (20.6%) received ocular lubrication, compared with nondiabetic patients (13.8%, P < .001). The difference was significant for all age groups and for both sexes (P < .001). A similar significant difference was prominent between diabetic and nondiabetic patients aged 60 to 89 years who were frequent users of ocular lubrication. Ocular lubrication consumption increased with poorer glycemic control (mean annual HbA1c levels). Multivariate analysis revealed this effect to be independent of age, sex, place of birth, or place of residence. KCS is significantly more common among diabetic patients. Poor glycemic control correlates with increased artificial tear use in diabetic patients.

Risk Factors for Postoperative Hemorrhage after Vitrectomy for Diabetic Retinopathy

Objective: To identify the potential risk factors for postvitrectomy diabetic vitreous hemorrhage (PDVH). Methods: A matched case-control nested into a retrospective follow-up study was done to review the surgical results in 68 consecutive eyes undergoing primary pars plana vitrectomy for vitreous hemorrhage. The eyes were divided into two groups based on the presence of PDVH (19 cases and 49 controls) and were matched on surgeon and the date of surgery. Twenty-three factors related to the preoperative examination and eight factors related to the operative procedure were analyzed. Statistical analysis was based on conditional logistic regression models with PDVH as the dependent variable. The mean follow-up interval was six months. Results: The factors associated with the incidence of PDVH were iris neovascularization (OR = 9.8, P = 0.03), lower extremity amputations (OR = 8.3, P = 0.02) and the use of antihypertensive agents within three months before vitrectomy (OR = 0.2, P = 0.04). Phakic and aphakic eyes of diabetic patients with lower extremity amputations would have a 70% probability of developing PDVH. This probability would have dropped to 30–40% had they been taking antihypertensive treatment. Conclusions: Iris neovascularization and lower extremity amputations increase the risk of PDVH. Antihypertensive treatment before vitrectomy decreases this risk.

Relation of diabetic macular edema to cytokines and posterior vitreous detachment

PurposeTo investigate whether angiotensin II (AII) or vascular endothelial growth factor (VEGF) is related to diabetic macular edema (DME) in patients with and without posterior vitreous detachment (PVD). DesignA case-control study. MethodsVitreous fluid samples were obtained at vitreoretinal surgery from 28 eyes of 28 DME patients without PVD, 8 eyes of 8 DME patients with PVD, 14 eyes of 14 nondiabetic patients, and 8 eyes of diabetic patients without retinopathy. The VEGF levels in vitreous fluid and plasma were determined by enzyme-linked immunosorbent assay, while AII levels were measured by radioimmunoassay. ResultsThe vitreous levels of AII and VEGF were significantly higher in DME patients with or without PVD than in nondiabetic patients or diabetic patients without retinopathy (without PVD: P < .0061, P < .0001, P = .0261, and P < .0001; with PVD: P < .0012, P < .0001, P = .0473, and P < .0001, respectively). There was no significant difference in the vitreous levels of AII or VEGF between patients with or without PVD (P = .4948 and P = .6642, respectively). The vitreous level of AII significantly correlated with that of VEGF in DME patients without PVD (P = .576) or with PVD (P = .488). AII and VEGF levels in vitreous fluid were significantly higher than the respective plasma levels. ConclusionsWe found that the vitreous levels of AII and VEGF were elevated in DME patients irrespective of the status of PVD. Angiotensin II and VEGF may be induced in the eyes and be related to the pathogenesis of DME.

Retinal thickness in healthy and diabetic subjects measured using optical coherence tomography mapping software.

To define the normal retinal thickness in healthy subjects using optical coherence tomography (OCT) mapping software and to assess the ability of OCT to detect early macular thickening in diabetic patients. Six radial scans centered on the fixation point were done on 60 healthy eyes and 70 eyes of 35 diabetic patients without macular edema on biomicroscopy. Retinal thickness was measured automatically with OCT mapping software. Mean retinal thickness was compared in subgroups of healthy patients based on age, sex, and eye, and in the eyes of diabetic patients and healthy subjects. Thickening was diagnosed if mean retinal thickness of an area was greater than the mean thickness + 2SD in the corresponding area in healthy subjects; or if the difference between right and left eye exceeded the mean difference + 2 SD in a given area in healthy subjects. In healthy subjects, mean retinal thickness in the central macular area 1000 microm in diameter was 170+/-18 microm. There was no significant difference according to age, or left or right eye, but central macular thickness was significantly greater in men than women (p=0.0139). No difference was observed between the eyes of healthy subjects and diabetic patients without macular edema on biomicroscopy, but OCT detected early macular thickening in 12 diabetic eyes. In this study average retinal thickness and mean local variations in a normal population were defined using a commercially available mapping software. OCT seems a sensitive tool for detecting early retinal thickening.

Aqueous flare induced by heparin-surface-modified poly(methyl methacrylate) and acrylic lenses implanted through the same-size incision in patients with diabetes

Purpose To compare the degree of blood–aqueous barrier (BAB) breakdown in eyes of diabetic patients after phacoemulsification and implantation of heparin-surface-modified poly(methyl methacrylate) (PMMA) or soft hydrophobic acrylic intraocular lenses (IOLs) performed using the same technique with the same incision size to determine the influence of the IOLs on postoperative inflammation independent of other surgical factors. Settings Department of Ophthalmology, University of Paris XIII, Bobigny, France. Methods In a prospective study, 44 eyes of 31 diabetic patients with or without mild to moderate diabetic retinopathy were randomly assigned to receive an HSM PMMA IOL (22 eyes) or a soft hydrophobic acrylic IOL (22 eyes) after standardized phacoemulsification surgery. Both types of IOLs had a 6.0 mm optic, were inserted unfolded, and were placed in the bag through a calibered 6.0 mm superior scleral incision. Anterior chamber flare was measured preoperatively and 1, 7, 30, and 240 days postoperatively using the Kowa 500 laser flare meter. Results The mean flare value was higher on the first postoperative day in both groups. There were no statistically significant between-group differences in flare scores or clinical parameters preoperatively or at any postoperative visit. Conclusions No significant difference was observed in inflammation between eyes having HSM PMMA IOL implantation or those having soft hydrophobic acrylic IOL implantation through the same-size incision. This indicates that hydrophobic acrylic and HSM PMMA materials induce the same degree of BAB breakdown after phacoemulsification in eyes of diabetic patients.

Anterior capsular contraction after cataract surgery in eyes of diabetic patients

AIMTo investigate change in the area of anterior capsular opening (ACO) after cataract surgery and its relation to the degree of postoperative anterior inflammation in patients with diabetes mellitus (DM).METHODS31...

Perifoveal microcirculation before and after vitrectomy for diabetic cystoid macular edema

PURPOSE: To quantify the perifoveal microcirculation in diabetic eyes before and after successful vitreous surgery for cystoid macular edema without posterior vitreous detachment, and to determine whether improvement in perifoveal microcirculation is associated with improvement in postoperative visual acuity. METHODS: In a prospective study, vitreous surgery was performed on 11 eyes of nine consecutive diabetic patients with cystoid macular edema, and their mean perifoveal capillary blood flow velocity was measured by fluorescein angiography with a scanning laser ophthalmoscope. Visual acuity was measured preoperatively and postoperatively, and the results were converted to the logarithm of the minimum angle of resolution (logMAR). The correlation between changes in logMAR visual acuity and capillary blood flow velocity was evaluated. RESULTS: In all nine eyes of seven patients with successful vitreous surgery, the cystoid macular edema resolved within 6 months after surgery, and the mean capillary blood flow velocity was significantly increased compared with that before surgery (2.19 mm per second versus 2.68 mm per second, P = .021); the changes in capillary blood flow velocity were significantly correlated with the changes in the logMAR visual acuity ( P = .024). CONCLUSIONS: Vitreous surgery may improve perifoveal microcirculation in the eyes of diabetic patients with cystoid macular edema and resolve the macular edema. Improvement of perifoveal microcirculation may be an important factor affecting visual outcome.

Elevated plasma vascular endothelial cell growth factor and thrombomodulin in juvenile diabetic patients.

The major cause of morbidity and mortality in patients with type 1 diabetes mellitus is vascular disease and the death rate in this group of patients can be up to six times that of the general population. Elevated levels of blood glucose can cause endothelial cell damage, and markers of endothelial damage such as von Willebrand factor (vWF) and thrombomodulin (TM) have been reported to increase in adult diabetic patients. Growth factors are strongly linked to smooth muscle cell proliferation that contributes significantly to the vascular occlusive process and it has been shown that vascular endothelial cell growth factor (VEGF) stimulates release of vWF from endothelial cells. Vascular endothelial cell growth factor levels have been shown to be increased in vitreous fluid from the eyes of diabetic patients with proliferative retinopathy compared to those without. In this study we have shown that plasma levels of both TM and VEGF were significantly increased in juvenile diabetic patients with no clinical evidence of vascular disease compared to normal age and sex-matched control subjects. Median TM levels were 45.5 ng/mL (I.Q.R. 34 to 56 ng/mL) and 61 ng/mL (I.Q.R. 41 to 72 ng/mL) in the control group and in the diabetic patients respectively (p = .0005) and median levels of VEGF were 19.6 pg/mL (I.Q.R. 15.9 to 28.1 pg/mL) in the control group and 37.1 pg/mL (I.Q.R. 22.1 to 50.3 pg/mL) in the diabetic patients (p = .027 Mann-Whitney U test). This suggests that microvascular disease begins in childhood and can be detected using laboratory tests before any clinical changes are apparent.

The electroretinogram sensitivity in patients with diabetes.

Electroretinograms (ERGs) were measured in 65 patients with diabetes and 10 control subjects. The single flash ERGs were recorded as a function of the stimulus intensity. A Naka-Rushton-type function was fit to b-wave amplitudes, measured as a function of stimulus intensity, to evaluate changes in ERG amplitude and sensitivity. We also measured the temporal aspects of the ERG b-waves. The ERG sensitivity tended to decrease as the retinopathy progressed. An average sensitivity loss in eyes with diabetic retinopathy was statistically significant. However, the eyes of diabetic patients without visible retinopathy did not show significant ERG sensitivity loss. There was less variability in temporal compared with amplitude measurements of ERG components, and significantly prolonged b-wave implicit times were found in all stages of retinopathy and in eyes of diabetic patients without retinopathy.

Macular Retinal Capillary Hemodynamics in Diabetic Patients

Macular retinal capillary hemodynamics was evaluated in 39 nonhypertensive insulin-dependent diabetic patients and 24 age-matched control subjects using the blue field entoptic simulation technique. A statistically significant 25% increase in macular capillary flow velocity was observed among the diabetic eyes along with a 37% decrease in the density of the entoptically perceived leukocytes. When the eyes of diabetic patients were graded according to the modified composite scale of Klein et al, capillary flow velocity was elevated in the group without retinopathy as well as in those with mild background retinopathy and those with preproliferative or proliferative retinopathy. The density of the entoptically perceived leukocytes was more severely reduced in those with retinopathy than in those without retinopathy but was poorly correlated with the composite grading scale. These results are consistent with the concept that in diabetes, capillary obstruction, either transient or permanent, may focally occur within the retina associated with vasodilation in the adjacent microvasculature because of relative tissue hypoxia.

The Effect of Plasma Glucose Decrement on Refractive Changes in the Eyes of Diabetic Patients

The Effect of Plasma Glucose Decrement on Refractive Changes in the Eyes of Diabetic Patients

Intramuscular Nerve and Neuromuscular Junction Alteration In Extraocular Muscles of Diabetic Mice

Diabetes mellitus is one of the commonest causes of neuropathy. Diabetic neuropathy is a heterogeneous group of neuropathic disorders to which patients with diabetes mellitus are susceptible; more than one kind of neuropathy can frequently occur in the same individual. Abnormalities are also known to occur in nearly every anatomic subdivision of the eye in diabetic patients. Oculomotor palsy appears to be common in diabetes mellitus for their occurrence in isolation to suggest diabetes. Nerves to the external ocular muscles are most commonly affected, particularly the oculomotor or third cranial nerve. The third nerve palsy of diabetes is characteristic, being of sudden onset, accompanied by orbital and retro-orbital pain, often associated with complete involvement of the external ocular muscles innervated by the nerve. While the human and experimental animal literature is replete with studies on the peripheral nerves in diabetes mellitus, there is but a paucity of reported studies dealing with the oculomotor nerves and their associated extraocular muscles (EOMs).

The Effect of Vitreous and Retinal Surgery on Corneal Endothelial Cell Density

The effect of vitreoretinal surgery on corneal endothelial cell density was studied prospectively in 69 eyes by comparing preoperative endothelial cell densities to postoperative data. The mean cell loss in eyes of diabetic patients did not differ significantly from those of non-diabetics. The mean endothelial cell loss in 30 phakic eyes which underwent pars plana vitrectomy without lens removal was 1.3 ± 1.4%. In aphakic eyes, vitrectomy and scleral buckling led to a mean cell loss of 12.6 ± 2.3%. When vitrectomy was combined with lentectomy and scleral buckling, the mean cell loss was 8.5 ± 1.8%, but eyes undergoing fluid-gas exchange in addition to these procedures suffered a mean cell loss of 16.9 ± 1.9%. The presence of the lens protects the corneal endothelium during pars plana vitrectomy, while fluid-gas exchange in aphakic eyes appears to have a detrimental effect.

Long-Term Results of Silicone Tube in Filtering Surgery for Eyes with Neovascular Glaucoma

We operated on 59 eyes with advanced neovascular glaucoma (37 eyes in diabetic patients and 22 eyes in patients with central retinal vein occlusion) using a trabeculectomy technique that includes a simple silicone tube as the draining element. Mean (+/- 1 S.D.) intraocular pressure preoperatively was 57 +/- 8.7 mm Hg. During follow-up periods ranging from one to five years, the mean intraocular pressure decreased to 27 +/- 16.5 mm Hg. Adequate control of intraocular pressure (24 mm Hg or less) was achieved in 37 eyes (63%). Only four eyes required enucleation. Nine silicone tubes had to be removed because of necrosis of the scleral flap and conjunctival perforation or because they were expulsed. Surgery relieved the severe ocular pain even when intraocular pressure was not satisfactorily controlled.