KOTA KINABALU: Diabetic retinopathy (DR) is a long term complication of diabetes mellitus and is now the leading cause of blindness in patients with diabetes.
A diabetic patient is 25 times more likely to have visual impairment compared to a non-diabetic person.
This was mentioned by KPJ Sabah Specialist Hospital Consultant Ophthalmologist and vitreo-retinal surgeon, Dr. Chin Kel Vin during a talk entitled “Keep an eye on diabetes” which was held on June 13. This talk is part of the public awareness programme organised by the hospital.
“The prevalence of diabetes mellitus in Malaysia is around 10 percent so an estimated three million Malaysians are affected. This number is expected to increase by 50 percent in the next 20 years. A recent study done at Universiti Malaya Medical Centre noted that 51.4 percent of diabetic patients had diabetic retinopathy.”
Dr. Chin explained that diabetes retinopathy is caused by microvascular damage due to long term diabetes.
“The mechanism of damage is due to microvascular occlusion and leakages. Microvascular occlusion is the blockage of the retinal blood vessels and results in formation of new vessels which are fragile. Left untreated, these new vessels can result in vitreous haemorrhage and retinal scar formation. Microvascular leakages cause swelling in the retina and may result in visual impairment.”
Explaining on the the classification of DR, it is divided into non-proliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR) and diabetic macular edema (DME).
According to Dr. Chin, patients with NPDR may still have a good vision but fundus examination will reveal multiple pathologies in the eye such as retinal hemorrhages, cotton wool spots and hard exudates.
“When left untreated, NPDR will progress with PDR where new vessels have formed in the retina. These new vessels are fragile and act like ‘time bombs’ when they suddenly rupture and vitreous haemorrhage occurs. This causes an instant blurring of vision in the affected eye.
“ The vitreous haemorrhage may resolve slowly but retinal scar formation is common. These scars will inevitably pull on the retina resulting in a tractional retinal detachment which has a poor visual prognosis.
“PDR is considered an ocular emergency and is treated with pan retinal photocoagulation (PRP). PRP involves the use of a laser to destroy peripheral retina in order to preserve central vision. This procedure aims to halt the progression of the disease rather than improve vision. PRP is usually completed in two or three sittings and is done as an outpatient procedure in the eye clinic.
“Surgery is indicated in PDR cases where there is a non-resolving vitreous haemorrhage or advanced scarring resulting in a tractional retinal detachment,” explains dr. Chin.
“The surgery is called vitrectomy and it involves the use of a sophisticated vitrectomy machine, microscope with viewing system and microsurgical instruments. Vitrectomy is essentially a ‘key-hole’ surgery whereby three small openings are made in the eye and instruments are placed through these openings to perform the surgery. At the end of surgery, PRP laser is usually done with an endolaser probe and the eye is filled with either a gas or silicon oil tamponade.”
According to Dr. Chin, the cost of vitrectomy is expensive due to the high cost of the machines used as well as the use of disposable single-use instruments and consumables like the gas or silicon oil tamponade.
“On the other hand, DME is caused of fluid leakages from the blood vessels resulting in the macula to swell. This causes a blurry, washed out vision. The primary risk factors for DME are the duration of diabetes , control of diabetes and coexisting diseases like hypertension and hyperlipidemia. An optical coherence tomography (OCT) is a medical imaging technique which uses a laser beam to create a high resolution 3-D image of the retina. An OCT scan helps to diagnose and monitor the progression of DME.”
In his presentation, Dr. Chin mentioned that the treatment options for DME are laser, intravitreal steroid injections and intravitreal anti-VEGF injections.
“ Laser has been the traditional method of treating DME but unfortunately, it is not very effective and 20 precent of patients will continue to lose vision. Steroid injections are more effective but has marked side effects such as glaucoma and cataract formation. Anti-VEGF injections such as Lucentis or Eylea is now considered the gold standard treatment for DME. This treatment results in visual improvement and usually requires three to five injections in the first year of treatment. Unfortunately, the main drawback is the high cost of the medication.”
Dr. Chin recommends that patients with diabetes mellitus should be treated by a multi-disciplinary team involving doctors, dieticians and pharmacists.
“With the advent of the Internet and ever increasing cost of living, patients may be tempted to self-medicate instead of seeking professional advice. This is not a good idea as diabetic complications are more expensive and difficult to treat,” said Dr. Chin.
Dr. Chin also stresses that a regular eye examination by an ophthalmologist is important to diagnose and monitor diabetic retinopathy.
“With early detection and treatment of diabetic retinopathy, loss of vision can be prevented.”
In conjunction with the talk, KPJ Sabah Specialist Hospital is offering a comprehensive eye examination package which consist of a dilated eye examination by an ophthalmologist , intraocular pressure check and fundus photography for RM150. For an appointment , please call 088-322069.