Author: Dr. Luis Felipe Hernández Matute
Diabetes is a major cause of blindness in the world. Furthermore, we see that the incidence of diabetes has increased in recent years as a result of factors such as a sedentary lifestyle, stress, poor eating habits, alcohol consumption, the higher rate of survival of the diabetic population, etc.
It is important to know that diabetes affects all the tissues of our body, therefore the eye can also be altered in many ways. We will briefly review some of the ways in which diabetes affects our eyes:
1. Paralysis of the extra-ocular muscles: This is presented as a deviation in alignment of the eyes or a drooping upper eyelid. In the latter case, the eye is closed and the patient cannot open it. This paralysis is due to the inflammation of the nerves that activate the muscles around the eye due to the sustained elevated levels of blood sugar that occurs in diabetes. Treatment of this type of paralysis is the normalization of glucose levels and administering neurotropic vitamins. Bell's palsy usually resolves completely over a period of 6 to 8 weeks.
2. Refractive changes (graduation of eyeglasses): The sudden elevation of blood glucose causes a change in the shape of the eye lens, which results in a marked increase or decrease in the graduation of the eyeglasses. This causes visual changes and the patient feels very anxious not knowing what is happening to him or her. When diabetes is controlled and the glucose levels return to normal, the lens generally returns to its original shape. Only then the vision and refractive needs stabilize.
3. Cataracts: In diabetic patients the process of clouding of the lens, called cataracts, is accelerated. Cataracts require surgery to restore vision.
4. Glaucoma is one of the most serious complications of diabetes. In addition to having a greater tendency to glaucoma, a diabetic patient may develop a very devastating form of glaucoma: neovascular glaucoma. This type of glaucoma requires a complex drug treatment and surgery to prevent a profound visual loss.
5. Diabetic retinopathy is a condition affecting the micro-circulation in the retina. It is produced by the occlusion of the capillary vessels that leaving the retinal tissue without oxygen. In response to this deprivation of oxygen, the body produces a series of vascular changes ranging from fluid buildup (edema), exudation (deposit of lipoid substances), bleeding and disorderly proliferation of new vessels that end up destroying the retina, with the consequent visual loss. Diabetic retinopathy is clinically divided into two forms:
a) Non-proliferative Diabetic Retinopathy, which is characterized by edema, exudates and retinal hemorrhages. It may be treated with the application of an intraocular drug and / or laser applications, as appropriate.
b) Proliferative Diabetic Retinopathy, which is characterized by neovascular proliferation, membrane formation and hemorrhages extending to the vitreous humor. The membranes can cause a tractional retinal detachment. This is the most advanced stage of damage to the internal structures of the eye. Treatment is complex and includes combinations of different surgical techniques (vitrectomy, membrane removal, replacing the detached retina, etc.), laser application and intraocular drugs. The visual recovery prognosis is limited and depends on the level of tissue damage.
6. Optic Neuritis is a complication where the optic nerve becomes inflamed and therefore causes severely decreased vision. It may be treated with cortico-steroid medications, and recovery may not be complete.
We have reviewed some of the eye complications that often occur in diabetic patients. It is essential to know that if you are diabetic, these are REAL COMPLICATIONS that can happen, but many of these are preventable if you maintain normal blood glucose levels.
A periodic ophthalmologic examination is the best way to detect any abnormal situation at an early stage preventing the terminal stages of the process.
To understand these facts we need to know how the eye works. In a general manner, the eye works very similar to a digital camera; it captures an image that is sent via a cable to the computer that analyzes it. If the cable from the digital camera to the computer is damaged, the latter cannot analyze the images the camera takes. The eye captures the image on the retina and it is then sent to the brain via the nerve fibers (which together form the optic nerve); if these fibers are damaged, the images perceived by the eye do not reach the brain, a process which can lead to blindness.
1. Glaucoma is the slow death of the nerve fibers of the optic nerve
The bundle of nerve fibers that carry the image to the brain can be damaged and if so, they will stop sending information to the brain. When this happens, the image does note reach the brain and vision is lost.
2. In glaucoma, the death of the nerve fibers is related to inadequate eye pressure.
The vast majority of people with glaucoma have an inadequate (higher) intraocular pressure, causing eye compression and therefore, death of the optic nerve fibers. The only globally accepted treatment for glaucoma is to lower the intraocular pressure levels with medication, laser or surgery.
3. During early stages of glaucoma there are no symptoms.
Glaucoma is also called the "silent thief of sight" because it progresses slowly causing vision loss and the patient does not perceive it until it is too late. That's why an early and periodic evaluation of the optic nerve can detect glaucoma at its initial stages, before there is any damage to the eye structures.
4. With glaucoma, side vision is affected.
In the vast majority of people suffering from glaucoma the first place where vision is lost is in the area around the nose. This is a point where the visual fields of both eyes overlap and that makes it difficult to perceive any changes. In advanced stages of glaucoma, central vision is preserved and vision on both sides of the eye is lost.
5. In general, you did nothing wrong to cause glaucoma. There are risk factors that can cause someone to develop glaucoma more than others. Family history and age (over 40 years) are the risk factors associated with glaucoma.
6. Direct causes of glaucoma may exist
There are several types of glaucoma: Primarily closed-angle and open-angle glaucoma. Among open-angle glaucoma, one of the most devastating types is presented in young people as a secondary effect from the use of topical steroids. Steroids are anti-inflammatory eye drops and make people feel fresh eyes but the intraocular pressure may rise causing damage to the optic nerve. If these drugs are used for a long time they can lead to blindness.
7. Overall exposure to world does not cause glaucoma
Personal habits, diet, and activity generally do not cause glaucoma, but there are some risk factors that may. The risk factors are different for open-angle and closed angle glaucoma. Some risk factors for closed-angle glaucoma are: age after 40, hyperopia (small eyes), the behavior of the internal structures of the eye (iris, lens, choroid, etc.) and pseudo-exfoliation.
8. The odds of going blind from glaucoma are low.
It is true that once the damage occurs it cannot be repaired, but if detected early, and given treatment to lower and stabilize intraocular pressure there might be no progression of glaucoma. Compliance and strict monitoring of the treatment program further reduces the chances of reaching blindness from glaucoma.
9. You do not have to change your life if you have glaucoma.
If you have glaucoma is ideal to keep a healthy diet full of vegetables and fruits and to exercise. It is best to avoid smoking and avoid positions where your head is below the waist for a long time (for example some yoga positions). Reading and drinking a glass of wine do not hurt anyone!
10. Follow-up appointments with the glaucoma specialist are very important to control glaucoma.
Glaucoma is a progressive disease and specialists should periodically follow up the optic nerve damage. To detect any change in glaucoma specialist should:
• Measure intraocular eye pressure (tonometry)
• Assess whether the angle is open or closed (gonioscopy)
• Examine the optic nerve (ophthalmoscopy, photographs, CT scans, etc.),
• Evaluate periferal vision (perimetry or visual field test)
In conclusion, glaucoma is damage to the optic nerve caused by raised intraocular eye pressure. Initially glaucoma has no symptoms but it can progress reducing the visual field all the way up to blindness. People who are at higher risk for glaucoma are those who have relatives with glaucoma and who are over 40 years old.
It is very important to get a complete evaluation (including intraocular pressure measurement and pupillary dilation) by an ophthalmologist, performed regularly to detect risk factors and avoid possible damage from glaucoma.
Author: Dr. Eileen Rinze,
The eye is like a ball filled with liquid. This liquid is called aqueous humor and it is constantly produced. If the eye does not have some sort of drain for this liquid to come out, there would be a point where the eye could break out due to excess liquid. The internal drainage system in charge of removing the aqueous humor of the eye is called the trabecular meshwork. It is like a sort of strainer that filters and directs the liquid into the circulation.
It is very important that this drainage system is in optimal conditions for the aqueous humor to drain out fast enough and maintain an ideal pressure inside the eye. The range of normal internal eye pressure is between 10 and 21 mmHg. When this drainage system is clogged or has scars, the ocular internal pressure may rise to incredibly high levels, as high as 70mmHg. This pressure can cause irreversible visual loss even in a few hours. Therefore, it is very important to have a routine screening once a year, because an ophthalmologist can detect any abnormality in the drainage system of your eyes and prevent an increased pressure and damage to the optic nerve.
Today you can often prevent these increases in intraocular pressure with the aid of a laser treatment. The reason for the indication of laser treatment is a narrow angle, referring to the angle formed between the iris and the cornea, where the trabecular meshwork is located.
Fig. 1 Open-angle and Closed-angle glaucoma
Narrow angle glaucoma, can be treated through a YAG Laser Peripheral Iridotomy. In this procedure, the Laser opens a microscopic hole in the iris that allows the fluid behind the iris to pass through it. This flattens the iris and often reopens the drainage.
Fig.2 YAG laser peripheral iridotomy
Fig. 3 Iridotomy
Depending on the anatomy of the eye, there is a possibility that the Peripheral Iridotomy will not open the drainage. If this is the case, another treatment called "Argon-Laser iridoplasty" could be necessary. This treatment stretches the iris to try to open the drain and it involves a higher amount of Laser shots.
Fig. 4 Argon-Laser Iridoplasty
Finally, there is another laser treatment to lower the intraocular pressure, even if there is an open drainage, or open-angle. This type of laser is called Argon-Laser Trabeculoplasty, and it has the ability to lower the intraocular pressure at the same degree as eye-drops would. It is often used in patients who have a contraindication to regularly use eye-drops. It is also used in patients who have failed to achieve the desired intraocular pressure with the maximum medical treatment and do not desire surgery. This laser opens small holes in the trabecular meshwork to increase the outflow of the aqueous humor.
Fig. 5 Argon-Laser Trabeculoplasty in open-angle glaucoma
The most important information you need to learn is that open or closed angle glaucoma may not show any symptoms and the only way to detect them is through a comprehensive eye exam. It is therefore important to visit your eye doctor regularly for early detection of any condition.
Vision Integral is a private ophthalmologic clinic in Guatemala City . We are a team of 9 specialists graduates of the best universities in Guatemala , the United States and Canada working together since 1987. We value above their overall health .
We are ready to answer any of your questions and needs