DIABETES AND THE EYE and effect of diabetic mellitus

diabetic and the eye

1. Ratumo caroline-HSM212-0758/2023 Langat julius-HSM212-0882/23 Scarlet wangui-HSM212-0623/23 Lerionka albert-HSM212-0629/23 Deonicia ndambuki-HSM212-0757/23 DIABETES AND THE EYE

2. INTRODUCTION Dabetes mellitus is a chronic metabolic disorder characterized by sustained elevated blood glucose resulting from defects in insuline secretion,action or both.Therefore if not well controlled leads to serious complications resulting in multiple diseases or disorders that affect multiple body organs.

3. Classification Type I diabetes( INSULIN DEPENDENT) Develops in childhood due to the destruction of the beta cells mass leading to absolute insulin deficiency. Has an abrupt onset, with thirst , increased appetite , excessive urina tion, and weight loss occurring over a period of several days. Type 2 diabetes: Usually develops in adulthood and is related to obesity. Lack of physical activity , and unhealthy diets.

4. This is the more common type of diabetes (Representing 90% of diabetes cases worldwide) Treatment may involve lifestyle changes and weight loss alone, or oral medication or even insulin injections.

5. pathogenesis Disease of the capillaries and small vessels (microangiopathy) causes Retinopathy, nephropathy, neuropathy and heart diseases . High blood glucose levels cause endothelial cells lining the blood vessels to take in more glucose than normal (these cells do not depend on insulin) they then form more glycoproteins on their surface than normal Also cause the basement membrane to grow thicker and weaker . The walls of the vessels become abnormally thick but weak, and therefore they bleed ,leak protein, and slow the flow of blood through the body.

6. Ocular effects of diabetes

7. Ocular effects of diabetes Diabetes can cause changes to virtually all structures of the eye. Eyelids Conjunctiva Cornea + tears Iris Lens Vitreous Retina Oculomotor nerves EOM

8. Lids Prone to i nfection s due to high blood sugar l evel . Recurrent styes and blepharoconjunctivitis. Xanthelasma ptosis due to damage to CN3 Dry eye dysfunction of meibomian glands

9. Conjunctiva Telangiectasis Sludging of the blood in conjunctival Vessels subconjunctival hemorrhage. Dry eye syndrome-accessory glands Recurrent infections

10. Tear film instability The incidence of dry eye is correlated with the level of glycated hemoglobin; the higher the level the higher the incidence of dry eye hence causing epithelial barrier dysfunction subsequently leading to corneal complications and then loss of lacrimal function unit dysfunction Accumulation of sorbitol within cells; cellular edema and dysfunction, results In lacrimal gland structure damage/dysfunction and the induction of decreased tear secreation Reduction in the number of goblet cells; reduces mucin production and the hydrophilic nature of the ocular surface leading to tear film instability

11. Paralyses of the Extraocular Muscles Extraocular motility disorders may occur in patients with diabetes, secondary to diabetic neuropathy, involving the third, fourth, or sixth cranial nerve. Rarely, simultaneous palsies of multiple extraocular nerves can occur. Patients with extraocular palsies present with binocular diplopia. Pupil sparing is an important diagnostic feature in diabetes-related third cranial nerve palsy, distinguishing it from surgical causes, such as intracranial aneurysm or tumor. In diabetic cranial nerve palsies, recovery of extraocular muscle function generally occurs within 3 months

12. Cornea 1)Diabetic corneal neuropathy This is a potential visual impairment condition caused by damage to the trigeminal nerve under chronic hyperglycemia, and results in reduction or loss of corneal innervation. Diabetic corneal neuropathy is characterized by photophobia, ocular irritation, or pain. The majority of corneal symptoms are the result of damage to the small Aδ and C nerve fibers of the cornea [3] . The loss of corneal sensory innervation causes corneal epithelial breakdown, delayed wound healing, and subsequently progresses to corneal ulceration, melting, and perforation.

13. 2)Corneal epithelium abnormality The corneal epithelium consists of cell layers and the basement membrane. The epithelium is an important barrier to the cornea, which can resist attacks from pathogens. However, diabetic patients are vulnerable to corneal epithelium dysfunctions, such as superficial puncture keratitis and epithelium erosion. Corneal epithelium abnormality is one of the most common and long-term complications of DM. 3)Corneal stroma abnormality DM may also cause alterations in the corneal stroma leading to corneal stroma disorder. DM may induce both structural and functional alterations in the corneal stroma, and these processes result in loss of corneal transparency and threaten the vision of the patients

14. 4. Corneal endothelium abnormality DM also exerts a profound effect on the corneal endothelium. Changes in endothelial morphological parameters, such as endothelial cell density. Functional disturbances may lead to increased endothelial permeability and endothelial autofluorescence, which subsequently result in the impairment of cornea dehydration and lead to corneal swelling

15. 5 Corneal limbal stem cell abnormality Corneal limbus is a narrow band of tissue that encircles the cornea. Under physiological conditions, corneal limbal epithelial stem cells give rise to progeny (transit amplifying cells), which differentiate into mature corneal epithelium during their radial migration towards the central cornea. The renewal of the corneal epithelium by LESCs may explain the clinically observed delays in diabetic wound healing. In DM, a reduction in the expression of LESC markers and slower wound healing in cultured diabetic LESCs have been observed, which may account for diabetic LESC dysfunction

16. 6. Corneal refractive fluctuation Fluctuations in blood sugar levels can affect the corneal shape and curvature. High blood sugar causes fluid to enter the corneal stroma, causing the cornea to swell and steepen, which can cause a temporary myopic shift.

17. Anterior chamber Non-granulomatous anterior uveitis, Vogt-Koyanagi-Harada syndrome, and panuveitis are the most frequent types of uveitis in patients with diabetes. There is a positive correlation between hyperglycemia and inflammation in the anterior chamber in patients with anterior uveitis. The behavior of uveitis in these patients is more aggressive and occurs more often bilaterally due to inflammatory mediators like interleukins and cytokines.

18. Pupil abnorma lities Miosis-damage to sympathetic nerves Sluggish pupil response- both parasympathetic and sympathetic pathways. Anisocoria-damage to oculomotor nerves .

19. Iris Rubeosis iridis: due to Retinal hypoxia, release of vasoproliferative substance (Angiogenic factor), causing Neovascularization of the iris. Iris atrophy and pigment dispersion Iritis

20. Intraocular Pressure Glaucoma : Is a complication of rubeosis of the iris A low intraocular pressure : Hypotony is caused in diabetic ketoacidosis (due to increased plasma bicarbonate levels).

21. Lens Refractive error Collection of the sugar alcohol sorbitol in the lens, due to inc rea sed aldose reductase activity , causes the lens to swell and changes its refractive power.

22. Myopic shift HYPERMETROPIC SHIFT

23. Cataract Cataract is a major cause of vision impairment in people with diabetes. It occurs 10-20 years after the onset of insulin dependent diabetes. Control of the diabetes with restoration of normal blood glucose levels stops progression of the opacity.

24. DIABETICS NEUROPATHY Paralysis of ocular muscles innervated by the third or sixth nerve. Sudden onset of diplopia and painful muscle paralysis associated with a homolateral headache. Short dur atio n of hy perg lycemia in a diabetic, the paralysis disappears s pontaneo usly with in several weeks This effect is explained by the diabetic peripheral circulatory disorder that develops in the feeding vessels to the facial nerves, often causing the microcirculatory insufficiency and edema that are responsible for the signs and symptoms of Bell palsy.

25. Diabetic pupillary defect Medical lesions in diabetes usually spare the pupil, compared with surgical lesions (aneurysm …), which involve the pupil. This is because of the microangiopathy, which involves the vasa nervorum, causing ischemia of the main trunk of nerve, and sparing the pial vessels, which supply the superficial pupillomotor parasympathetic fibers

26. Diabetic Retinopathy Retinopathy is the most important ocular complication of diabetes It is more common in type 1 diabetes than in type 2, and sight-threatening disease is present in up to 10%. Proliferative diabetic retinopathy (PDR) affects 5–10% of the diabetic population. Type 1 diabetics are at particular risk, with an incidence of up to 90% after 30 years .

27. RISK FACTORS Duration of DM Control of diabetes Will not prevent but delays Hypertension Renal disease Pregnancy Obesity, hyperlipidaemia , smoking, anaemia Duration and diabetic retinopathy

28. DR Pathogenesis

29. CLASSIFICATION

30. .

31. Diabetic papillopathy Diabetic papillopathy is an uncommon ocular manifestation of diabetes mellitus (DM). The underlying path ogenesis is unclear but it maybe the result of small vessel disease . Presentation is usually with mild optic nerve dysfunction and slow progression .

32. Investigations Random blood sugar Optical coherence tomography Fluorescein angiography Bscan

33. OCT

34. Management Observation Medical treatment Anti VEGF Laser Vitrectomy

35. Medical treatment: Glucose control : Controlling diabetes. Maintaining the hbaic level in the 6-7% range. Level of ac tivit y Maintaining a healthful lifestyle with regular exercise can help reduce the complication of diabetes and DR. Blood pressure control. Lipid-lowering therapy.

36. Anti VEGF Bevacizumab ------- avastin Ranibizumab ------- lucentis Aflibercept ----------- eylea

37. Laser treatments

38. Reduces severe visual loss Indications: focal laser . Indication DME S eal leaking of microaneurysm Grid laser Indication DME Diffuse capillary leakage treatment PRP laser PDR-Destruction of peripheral ischaemia Laser therapy :

39. References 1. Kanski 9 th Edition 2. Ak Khurana 3 internet