Overview

Diabetic retinopathy and macular pucker are both different eye disorders that can have serious consequences for your eyesight. There are certain risk factors and symptoms for both disorders that overlap but there are also several distinctions that will be discussed in this article.

Diabetic retinopathy

Diabetic retinopathy is a microvascular disorder, which means that it involves changes in the small blood vessels in your eyes. It is associated with the long-term effects of diabetes. It is more common in patients with type 2 diabetes, with around 77.3% of patients with diabetic retinopathy having type 2 diabetes and about 25.1% of patients with diabetic retinopathy having type 1 diabetes.¹ Type 1 diabetes is a disorder when patients do not produce insulin. The insulin receptors, which are where the insulin binds and exerts its effects, are functional, therefore, patients can inject insulin with doctor's advice and manage their symptoms.² However, type 2 diabetes patients produce insulin, but the receptors do not respond to it; this means that the patients require lifestyle changes, such as diet and sport.³ Diabetes of either type, when untreated, can have several health consequences such as diabetic retinopathy.

Background of developing diabetic retinopathy

Chronic hyperglycaemia

Consistently high blood sugar can cause pathways that are not usually utilised as a way to process glucose to be used. This is fine short-term however, if this occurs for a prolonged period it can cause oxidative stress which results in activation of cells called cytokines which increase the vascular permeability, meaning that the blood vessels are more absorbent and this can cause problems to occur, cytokine activation can also cause microvascular occlusion – which means the small blood vessels are blocked.

Oxidative stress means that there is a higher activation of reactive oxygen species, which can lead to cell and tissue damage

Morphological changes

The early signs of diabetic retinopathy are changes in the eye which can be detected by an ophthalmologist, the morphological changes include loss of pericytes which are cells that line the vessels to protect them, basement membrane thickening, loss of endothelial cells which line the inside of the vessels and increased vascular permeability which means that blood vessels absorb things they would not absorb in normal circumstances.

Müller cells

Müller cells are primary glial cells of the retina, and they are responsible for maintaining the structural integrity of the retina and the regulation of the blood-retinal barrier and retinal blood flow. When someone has diabetic retinopathy, there is a lower number of channels called Kir4.1 channels, and this causes an increased intake of potassium which in excess can cause swelling of the Müller cell,s which can cause them to not function properly.

Symptoms

There are various symptoms of diabetic retinopathy, which include:

• Blurred vision
• Distorted vision
• Floaters
• Total vision loss (this is rare and unlikely to happen if it is diagnosed and treated)

Risk factors¹

Modifiable risk factors 

These can be altered by the individual:

• Hypertension, which means high blood pressure
• Obesity
• Dyslipidaemia, which means high cholesterol
• Poor glycaemic control – which means high blood glucose and/or sugar levels, this is usually associated with untreated diabetes. Meaning your fasting blood glucose is >130mg/Dl
• Nephropathy – which means that there is a loss of kidney function
• Chronic hyperglycaemia – continuously high blood sugar levels

Non-modifiable risk factors 

These cannot be altered by the individual:

• Puberty
• Pregnancy

Less common risk factors

• Inflammation
• Hormonal influences, for example, leptin (leptin is a hormone associated with feeding and hunger)
• Genetic factors

Diagnosis of diabetic retinopathy

If an ophthalmologist suspects diabetic retinopathy, then a full history of the patient’s health must be taken including how long the patient has had diabetes for, how long it has been treated for and whether it is type 1 or type 2 diabetes.

Treatment of diabetic retinopathy⁴

To prevent diabetic retinopathy or prevent its progression it is important to manage the symptoms of diabetes, including controlling your blood sugar and cholesterol. However if the diabetic retinopathy progresses there are treatments to help manage the symptoms:

• Laser treatment
• Eye injection
• Steroid eye implants
• Eye surgery

Laser treatment

Laser treatment uses a laser to remove new blood vessels because at advanced stages of diabetic retinopathy, the new blood vessels can be weak and result in bleeding into the eye. A doctor will give you local anaesthetic drops into your eyes and also widen your pupils and contact lenses to be able to focus the laser on the correct point. This treatment takes approximately 20-40 minutes, and although it can help reduce the eye changes it does not improve sight.

Side effects of laser treatment include:

• Blurred vision
• Increased sensitivity to light
• Aching or discomfort

Eye injections

Injections of a medication called anti-VEGG may be injected directly into the eyes to prevent the formation of new blood vessels at the back of the eyes. The injections are given once a moth and once there are improvements to your vision, then the injections can be given less frequently or stopped altogether.

Potential side effects:

• Eye discomfort
• Bleeding inside the eye
• Floaters
• Feeling like there is something in your eye
• Watery, dry or itchy eyes

Steroid implants

If eye injections do not work, you may potentially be offered an eye implant called a intravitreal implant containing a steroid medicine called dexamethasone. The implant is injected into the eye and it slowly releases dexamethasone over a period of time, this helps reduce the swelling in your eye and can improve eyesight. The implant dissolves and can help to improve your eyesight.

Possible side effects:

• Headaches
• Increased pressure in the eye
• Cataracts
• Bleeding in your eye
• Eye pain
• Problems with your eyesight

Eye surgery

If a large amount of blood has collected in your eye or there is lots of scar tissue it is likely that surgery will be recommended, the surgeon will make a small incision in your eye before removing the vitreous humour which is a transparent jelly like substance that fills the space behind the lens of the eye. You will need to wear a patch over your eye and likely have blurred vision for some time after the operation. However, your vision should return to normal.

Risks:

• Cataract
• Bleeding into the eye
• Retinal detachment
• Fluid buildup in the cornea
• Infection

Macular pucker⁵

Macular pucker is a wrinkling of your retina due to scar tissue; the retina is an area of the eye that contains cells called nerves that specifically respond to light. The macular area of the eye is where the light-sensing nerves come together.

Symptoms

Macular pucker commonly occurs in one eye, but it can occur in both. However, typically one eye is more affected than the other. It causes symptoms such as:

• Distorted vision
• Straight lines appearing wavy
• Blurred vision
• Double image
• One eye sees things larger than the other – glasses cannot fix this

Causes and risk factors

There are many different causes of macular pucker, some of which include:

• Tears in the retina
• Retinal detachment
• Eye surgery
• Eye trauma
• Infection
• Diabetes related retinal disease

Diagnosis

There are several techniques to diagnose macular pucker performed by professional ophthalmologists:

• Amsler grid eye test – a grid is presented to you, and through a series of questions, a doctor will be able to determine whether there is damage to the macula
• Optical coherence tomography, an imaging method that takes pictures of your retina and allows detection of whether there is any puckering present in the macular region

Treatment

Glasses will not fix all of the symptoms of macular puckering. However, they may be able to improve your overall vision

Surgical treatment may be advised for example a surgery called vitrectomy with membranectomy which is a procedure that removes the scar tissue from the retina, it is important to note that after surgery you will likely need to take time off for approximately 2-4 weeks, and it may take 3 months for vision to be back to normal.

Risks of surgery:

• Bleeding
• Infection
• Retinal tear or detachment
• Worsening of cataracts
• Macular hole
• Glaucoma
• High eye pressure

Summary

There are some similarities but also distinct differences in the causes and treatments of macular pucker and diabetic retinopathy. However, there is an overlap in symptoms and therefore, it is important to go to a specialist if you notice any changes in your vision or are worried about your vision.