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Diabetic Retinopathy Treated with Laser Photocoagulation and the Indirect Effect on Glycaemic Control

The prevalence of diabetes has been accelerating at an alarming rate in the last decade; some describe it as an epidemic. The study of the pathogenesis of the epiretinal membrane promotes the research on the underlying mechanisms of PDR progression, contributing to the suppression of visual loss. The electronic databases Medline and Embase were searched for cohort studies that evaluated DR in type 2 or type 1 diabetic patients and reported total mortality and/or fatal and nonfatal CV events, including myocardial infarction, angina pectoris, coronary artery bypass graft, ischemic changes on a conventional 12-lead electrocardiogram, transient ischemic attack, nonfatal stroke, or lower leg amputation. Data of 4080 patients whose primary cause for VI was DR were analysed. Since the late 1990s, the occurrence of diabetic nephropathy has been steadily increasing; this condition is now the dominant cause of end-stage renal disease (ESRD) in many countries. There was no correlation between the change in visual acuity and any of the studied background parameters. The Diabetic Retinopathy Vitrectomy Study Research Group.

Mean initial visual acuity was equal to or better than 20/40 in 32 eyes (80%). A reported safe dose is 3000 rads/30 Gray, 1000 rads/10 Gray per week in five fractions (200 rads/2 Gray per session) [3], although cases have been reported with lower doses of radiotherapy [2, 4]. Ifthe manifestation ofthe sympton is less marked than in standard photograph one, it is referred to as < 1 ; if it is more marked than in standard photograph two, it is referred to as > 2. Conclusion. You can also use indirect laser for pan-retinal photocoagulation. Carotid reconstruction surgery and ophthalmological treatment were not successful for recovering a satisfactory visual outcome in OIS. Immunoreactivity for CD34 clearly detects microvessels in epiretinal membranes (a, b).

They also reported one case of a self-repaired choroidal detachment and one case of vitreal and subretinal hemorrhage that required a second vitrectomy procedure. Diabetic macular edema (DME) can occur at any stage of DR and is regarded as the principal cause of vision loss in patients with diabetes [2]. Retinal hypoxia is implicated in the pathogenesis of DME and in the development of retinal neovascularization. Get a printable copy (PDF file) of the complete article (2.4M), or click on a page image below to browse page by page. In previously published studies we have already shown the well-established involvement of vascular endothelial growth factor (VEGF) and the contribution of other growth factors [4] in the pathogenesis of PDR [5] and NPDR with DME [3]. Clinical trials have also shown the effectiveness of laser photocoagulation, vitrectomy, and control of hyperglycemia and hypertension for DR [1]. In this study we examined the hypothesis that previous treatment with argon laser photocoagulation in patients with diabetes is positively related to their glycaemic control.

The study was conducted prospectively in 2009-2010 at the Aristotle University of Thessaloniki, Greece, following the tenets of the Declaration of Helsinki. Approval of the Institutional Review Board Ethics Committee of the Medical School of Aristotle University of Thessaloniki was also obtained. All patients signed an informed consent after the purpose of the study was explained in detail to each subject. Patients with diabetes were included in the study and were separated into 2 groups according to treatment (group A) or not (group B) with argon laser photocoagulation. Inclusion criteria for both groups included (i) patients with type 2 diabetes mellitus, (ii) visual acuity ranging between 20/40 and 20/70 for each eye of the same subject, (iii) NPDR with DME diagnosed with biomicroscopy and confirmed on fundus fluorescein angiography (FFA). Exclusion criteria for both groups included (i) previous treatment with laser photocoagulation, (ii) no evidence of PDR or clinically significant macular edema (CSME) on biomicroscopy or FFA. All patients with diabetes included in the study were offered laser treatment after receiving counseling by the same retinal specialist related to their management of DR and were provided information leaflet regarding the laser treatment and were treated in the same hospital by the same retinal specialist.

Glycaemic control was estimated by measuring blood levels of HbA1c (Hemoglobin A1c) in four consecutive measurements, that is, at baseline and at 3 months, 6 months, and 12 months after laser treatment in group A and in four consecutive measurements at baseline and at 3, 6, and 12 months in group B as well. The Kenalog intraocular injection is targeted at patients with cases of clinically significant macular edema, cystoids macular degeneration, or cysts within the retina, as well as those with proliferative diabetic retinopathy that has been resistant to laser treatment. Statistical analysis was performed with the Statistical Package for the Social Sciences (SPSS). The differences between groups were analyzed by multivariate analysis of variance (MANOVA). The differences between groups with respect to sex were tested by chi-square test (Table 1). A two-tailed value of less than 0.05 was considered to indicate statistical significance. Seventy-two patients with diabetes were included in the study: group A (treated with laser) 36 patients and group B (untreated) 36 patients.

Characteristics of patients included in the study are shown in Table 1. There were no significant differences between the two diabetic groups with respect to sex, age, duration of diabetic disease, and blood levels of HbA1c prior to treatment with argon laser photocoagulation. Furthermore, there were also no significant differences between the two groups with respect to comorbidities such as systemic arterial hypertension (SAH), dyslipidemia, renal dysfunction and atherosclerotic cardiovascular disease, their income, educational level, habits (smoking and/or drinking), and insurance status (private versus social). Blood levels of HbA1c in group A were significantly lower 3 months after laser treatment as compared to blood levels of HbA1c before laser treatment (% versus %, , MANOVA). Interestingly, blood levels of HbA1c in group A sustained significantly decreased after 6 months after laser treatment as compared to blood levels of HbA1c before laser treatment (% versus %, , MANOVA). More interestingly, blood levels of HbA1c in group A sustained significantly decreased even after 12 months after laser treatment as compared to blood levels of HbA1c before laser treatment (% versus %, , MANOVA). No significant negative correlations between the extent or the type (focal, grid, or both) of laser photocoagulation and the concentration of HbA1c in blood after laser treatment were found in group A (all values > 0.05).

Blood levels of HbA1c in group B did not differ significantly in four consecutive measurements (% versus %, % versus %, and % versus %, resp., all ) (Table 2). No significant positive correlations were found between blood pressure (BP) levels, body mass index (BMI), weight, and the laser treatment. But there were positive correlations between some social habits, such as smoking, alcohol, exercise, and the laser treatment but not significant ones. Panretinal (PRP) and focal or grid laser photocoagulation, when indicated in patients with PDR or DME, respectively, has beneficial effect on DR by reducing the risk of severe visual loss even more than 50% [6–8]. In our study, we came to an interesting observation that previous argon laser photocoagulation in patients with diabetes is positively related to their glycaemic control. A feasible explanation for this trend is that patients with diabetes who undergo laser photocoagulation treatment apparently consider laser photocoagulation as an operation and subsequently attain the attitude of the operated patient, who in general complies better to doctor’s guidelines, such as antidiabetic treatment, exercise and diet, achieving stricter glycaemic control, and hypothesis that was generally supported from our Institutional Psychologist. Additionally, the improved glycaemic control could be attributed to a psychological effect of becoming motivated to improve the health status [9] after having been subjected to laser photocoagulation and a stark realization of the diabetic disease that is leading to impaired eyesight.

With the inherent fear of vision loss in this patient population some had probably experienced some degree of visual loss and may fear losing more, which could motivate them to change their behaviour. Also the discomfort or pain associated with the procedure [10] could be a potential motivator to alter diet to prevent the likelihood of requiring further courses of treatment. On the other hand, patients with diabetes who reject the laser treatment obviously do not realize the seriousness of their eye involvement (either as a result of their own perception or because of a patient-doctor communication failure) and thus continue to their previous way of living (in terms of glycaemic control, systemic follow-ups with their diabetologists, healthy eating). We also suggest that diabetologists have an additional reason to encourage patients with diabetes to visit an ophthalmologist [11], expect for direct treatment of DR [3, 6, 8]; they should expect better glycaemic control in certain cases. We are not aware if the same results for better glycaemic control imply for patients who had laser for PDR; to our experience, because PDR does not always imply severe visual loss, patients with PDR do not always realize the seriousness of DR eye disease. To our knowledge, this is the first study that examines the possible “indirect effect” of laser treatment to glycaemic control. Larger number of patients and duration of glycaemic control could safely examine more related parameters and support our findings.

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