Sub-Retinal Hemorrhage - A Rare Complication After LASIK Surgery

sub-retinal hemorrhage is a serious complication of LASIK surgery

The ever-growing use of LASIK to correct or improve vision is an evidence of many advantages and benefits associated with LASIK. Relatively lower costs, high safety profile, ease, simplicity and quick recovery are some of those benefits. It is also fairly painless, and it can be done without a hospital stay. Like many other lasers, LASIK uses complex systems for producing and focusing the light beam, making them more precise than other kinds of surgery. While no surgery (including LASIK) is 100% safe and free of side effects, there is, indeed, a very low risk of infection and other complications associated with LASIK.

One of such rare complications that has been observed during and after a few patients undergoing LASIK procedure is sub-retinal hemorrhage.

To better understand the concept of "sub-retinal hemorrhage", you should first familiarize yourself with the following basic terms:

What is retina?
The retina is a thin layer of light-sensitive nerve fibers and cells that covers the inside of the back of the eyeball. In order for you to see, light must pass through the lens of the eye and focus on the retina.

What does retina do?
For the sake of understanding, you can assume that your retina acts like a camera. It takes a "picture" and transmits the image through the optic nerve to the brain.

What is hemorrhage?
In its simplest definition, the term hemorrhage refers to the blood loss as a result of bleeding.

What are the meanings of the term "sub-retinal"?
The term "sub" literally means "below" or "beneath". Accordingly, "sub-retinal" means "below or beneath the retina". It happens when small blood vessels in the retina leak fluid or tiny amounts of blood, blurring the vision and, if left untreated, it could lead to a more severe complication, known as "retinal detachment" which often results in complete vision loss or blindness.

Retinal detachment can be defined as an eye condition in which the retina pulls away or "detaches" from the back of the eye.

Definition of sub-retinal hemorrhage
Therefore, sub-retinal hemorrhage can be defined as the "blood loss or bleeding that occurs below or beneath the surface of retina due to the occasional damage to small retinal blood vessels caused by improper or inexperienced use of LASIK laser.

What causes sub-retinal hemorrhage during LASIK?
In its simplest definition, LASIK is a minor surgical procedure which reshapes the cornea by means of an excimer laser. During the reshaping of the cornea by an excimer laser, not all laser energy is consumed in the ablation process and a small amount of laser energy also enters the eye which poses a great risk for the retina present at the back of the eye. This remaining pulse energy propagates further through the eye and actually hits the retina and the strongly absorbing retinal pigment epithelium behind. This sudden energy burst significantly increases the inner of retina rise which can damage the retina depending on its value and time duration occurs and therefore influences the ability to see. It has been suggested that this could be one of the causes of abnormal expansion of blood vessels of retina which often explode to leak blood beneath the retina, a phenomenon known as "sub-retinal hemorrhage".

Can we prevent sub-retinal hemorrhage during LASIK?
One of the suggested reasons for this is not the LASIK laser itself but is often the inexperienced use or lack of proper knowledge in carrying out the LASIK expertly. For example, if a too high average laser power with a low numerical aperture is chosen, the surgeon can easily damage the retina and affect the visual acuity. One of the best strategies to deal with this is to use lower laser pulse power with increasing repetition rate. This not only increases the irradiated area, but clearly drops the maximum temperature reached inside the irradiated tissue.

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