Diabetic retinopathy

Ocular changes and disorders associated with Obesity

Published on: 27th July, 2018

OCLC Number/Unique Identifier: 7795938194

Obesity is a chronic and metabolic disease with a high increasing prevalence worldwide. It has multifactorial pathogenesis including genetic and behavioral factors [1-5]. Overweight and obesity have been defined and classified by the World Health Organization (WHO) and the National Institutes of Health (NIH) [2,3]. A person with a normal weight has Body Mass Index (BMI) of 18.5-24.9. A person with a BMI under 18.5 is called underweight. An adult having a BMI of 25-29.9 is overweight and pre-obese. Class 1 obesity is defined as a BMI between 30.00-34.99. Class 2 (Severe) Obesity is to have a BMI between 35.00-39.99. Morbid (Extreme, Class 3) obesity is to have a BMI over 40 [1-5]. Obesity is significantly associated with enhanced morbidity and mortality rates. It has also various economic, medical and psychological effects and causes health problems including many systemic diseases, economic costs and burdens, social and occupational stigmatization and discrimination and productivity loss [4-6]. Obesity carries the increased risk of development of many systemic and chronic diseases, including sleep apnea, depression, insulin resistance, Type 2 (adult-onset) diabetes, Gout and related arthritis, degenerative arthritis, hypertension, dyslipidemia, heart disease such as myocardial infarction, congestive heart failure, or coronary artery disease, polycystic ovary syndrome and reproductive disorders, Pickwickian syndrome (obesity, red face and hypoventilation), metabolic syndrome, non-alcoholic fatty liver disease, cholecystitis, cerebrovascular accident, colonic and renal cancer, rectal and prostatic cancer in males, and gallbladder, uterus and breast cancer in females [6-12]. In recent years, some publications reported that obesity has been strongly associated with some ocular diseases including age-related cataract and maculopathy, glaucoma, and diabetic retinopathy [13-16]. The recent reports demonstrated that the central corneal thickness and intraocular pressure were increased while as mean thickness of RNFL and retinal ganglion cell and choroidal thickness (CT) were decreased in the morbidly obese subjects [17-19]. However, another study has reported that CT increased in obese children [20]. On the other hand, a recent study reported that all values of the specific tests used to evaluate the ocular surface were within the normal range [21]. In some experimental studies, it has been demonstrated that obesity may cause retinal degeneration [22,23]. Additionally, in a past meeting presentation, it has been speculated that keratoconus is associated with severe obesity [24]. Teorically, idiopathic intracranial hypertension, and papilledema may also be associated with obesity [25]. Obesity may be also a cause of mechanical eyelid abnormalities such as entropion [26]. However, further investigations are needed to detect the significant relationship between these diseases and obesity. On the other hand, the ocular surgeries of obese patients are difficult compared to normal weight-subjects. The posterior capsule rupture and vitreous loss may easily develop during cataract surgery of these patients because obese patients have an elevated vitreous pressure and operating table cannot often be lowered or surgeon’s chair cannot be elevated sufficiently to provide the clear viewing of the operating area and tissues. So, some different surgical manipulations such as standing phacoemulsification technique and reverse Trendelenburg position have been developed. Additionally, the standing vitrectomy technique has been used for vitreoretinal interventions in morbidly obese patients [27,28]. In conclusion, all obese subjects should be subjected to a completed ophthalmological examination and to relevant clinics for the detection of possible comorbidities and diseases
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A study to correlate the central corneal thickness to the severity of diabetic retinopathy and HbA1c levels in type 2 diabetes mellitus

Published on: 14th December, 2021

Background: Diabetic retinopathy (DR) is one of the most common causes of preventable blindness. Patients with Diabetes Mellitus (DM) develop not only DR but also corneal endothelial damage leading to anatomical and physiological changes in cornea. Central corneal thickness (CCT) is a key parameter of refractive surgery and Intraocular pressure (IOP) estimation. The role of CCT and higher glycemic index in DR needs to be researched upon.Objectives: To identify the corneal endothelial morphology in patients with type 2 DM, to measure the Central Corneal thickness (CCT) in patients with type 2 Diabetes Mellitus, to assess the relationship of CCT with HbA1C levels in the study group and to correlate the CCT with the severity of Diabetic retinopathy in the study group.Methods: A cross-sectional observational study was conducted between January 2018 and June 2019 in Vydehi Institute of Medical Sciences and Research Centre, Bangalore. The study included 100 subjects with type 2 DM for 5 years or more. Patients with comorbidities that may affect the severity of DR or alter CCT and other corneal endothelial parameters such as glaucoma, previous ocular surgery or trauma, corneal degenerations and dystrophies, chronic kidney disease and Hypertension were excluded. DR was assessed by dilated fundoscopy, fundus photography and optical coherence imaging of the macula and graded as per the Early Treatment of Diabetic Retinopathy Study (ETDRS) classification. CCT and other corneal endothelial parameters were measured through specular microscopy. Relevant blood investigations including blood sugar levels were done for all patients.Statistical analysis: Relationship between CCT and grades of DR and HbA1c levels were established using the Chi-Square test. The level of significance was set at p < 0.05.Results: The mean CCT in patients with no diabetic retinopathy, very mild and mild non-proliferative diabetic retinopathy (NPDR), moderate NPDR, severe and very severe NPDR and PDR was 526.62 ± 8.084 μm, 542.07 ± 8.713 μm, 562.16 ± 8.255 μm, 582.79 ± 7.368 μm and 610.43 ± 18.256 μm respectively. Analysis of the relationship between CCT and severity of DR showed a statistically significant positive correlation between the two parameters (Pearson r = 0.933, p = 0.001). Beyond this, a correlation was found between all the corneal endothelial parameters and severity of DR. Multivariate analysis showed that advanced DR was positively correlated with CV (r  = 0.917) and CCT (r = 0.933); while it was negatively correlated with ECD (r = -0.872) and Hex (r = -0.811). A statistically significant correlation was also found between CCT and HbA1c. Also increasing age, duration of DM and higher glycemic index were positively correlated with severity of DR. Conclusion: This study, by demonstrating a strong correlation between the central corneal thickness to the severity of DR and HbA1c levels emphasizes the importance of evaluation of corneal endothelial morphology in the early screening and diagnosis of microvascular complications of DM.
Cite this ArticleCrossMarkPublonsHarvard Library HOLLISGrowKudosResearchGateBase SearchOAI PMHAcademic MicrosoftScilitSemantic ScholarUniversite de ParisUW LibrariesSJSU King LibrarySJSU King LibraryNUS LibraryMcGillDET KGL BIBLiOTEKJCU DiscoveryUniversidad De LimaWorldCatVU on WorldCat