The key difference between hydrodissection and hydrodelineation is that hydrodissection takes place between the lens capsule and lens cortex, while hydrodelineation takes place between the endonucleus and epinucleus.
Cataract surgery is carried out to restore the vision of patients who have cloudy vision as a result of cataracts. Phacoemulsification is the most common technique used in cataract surgeries. During this process, a tiny probe is inserted into the eye. This device usually emits ultrasound waves, which soften and break the lens to remove through suction. This is also known as small incision cataract surgery. Hydrodissection and hydrodelineation are two vital techniques that easily facilitate phacoemulsification.
CONTENTS
1. Overview and Key Difference
2. What is Hydrodissection
3. What is Hydrodelineation
4. Similarities – Hydrodissection and Hydrodelineation
5. Hydrodissection vs Hydrodelineation in Tabular Form
6. Summary – Hydrodissection vs Hydrodelineation
What is Hydrodissection?
Hydrodissection is a technique used during cataract surgery where the lens capsule is separated from the lens cortex with the use of a balanced salt solution. It is performed between the capsule and cataract cortex in the eye to free the adhesions of the cataract from the capsular bag. This allows it to rotate fully. Hydrodissection is performed after creating the capsulorhexis. During the process, a cannula consisting of a balanced salt solution is inserted into the eye, directed straight from the main incision. It is gently placed under the anterior capsule, and this moves forward, ensuring visualization of the tip. The anterior capsule is lifted slowly while the cannula points towards the lens of the equator carefully without damaging the zonules and puncturing the capsule. A slow and continuous flow of salt solution generates a fluid wave, cleaving the cortex from the posterior capsule. This fluid wave causes the bulging of the lens upwards from the pressure created by the flow of salt solution. The central part of the lens is depressed carefully with the cannula. This forces the fluid trapped to escape and disrupt equatorial cortical-capsular adhesions.
Usually, a successful hydrodissection is performed when the nucleus rotates easily by the cannula. When this technique is performed properly, the lens is mobile and gets detached from the surrounding capsule. This facilitates an easy extraction during phacoemulsification. An effective hydrodissection also allows an easy cortical clean-up, reducing the risk of capsular rupture during the process of cortical extraction.
What is Hydrodelineation?
Hydrodelineation is a technique used in cataract surgery to separate the outer epinuclear shell from the central endonucleus. It is also performed after creating the capsulorhexis. The central endonucleus has a higher density than the outer epinuclear shell; therefore, it requires a higher amount of ultrasound energy to remove.
During this technique, the canula is placed in the nucleus and positioned downward and forward toward the central plane until the nucleus starts to move. As the nucleus moves, the endonucleus is found. The cannula directs to the endonucleus, and the balanced salt solution is gently and steadily injected along a pathway. The fluid usually follows the path that has the least resistance, cleaving the epinucleus from endonucleus. A successfully carried out hydrodelineation gives out a golden ring or dark circle around the endonucleus. This signifies a circumferential division of the nucleus. The main purpose of this technique is the temporary maintenance of the epinuclear shell, which acts as a protective coat. The remaining portion of the epinuclear shell keeps the capsule stretched, preventing it from tearing.
What are the Similarities Between Hydrodissection and Hydrodelineation?
- Hydrodissection and hydrodelineation are vital techniques used in cataract surgeries.
- Both are performed after creating the capsulorhexis.
- Both require a cannula containing a balanced salt solution.
- They are phacoemulsification techniques that use ultrasound.
- The cannula with the balanced salt solution is directed towards the central plane in both phenomena.
What is the Difference Between Hydrodissection and Hydrodelineation?
Hydrodissection takes place between the lens capsule and lens cortex, whereas hydrodelineation takes place between endonucleus and epinucleus. Thus, this is the key difference between hydrodissection and hydrodelineation. Hydrodissection is a technique used to separate the lens capsule from the lens cortex, while hydrodelineation is a technique used to separate the outer epinuclear shell from the central endonucleus. Moreover, the main purpose of hydrodissection is to remove tight attachments between the inside of the lens capsule and the outer cortical layer of the lens. The purpose of hydrodelineation is to maintain the epinuclear shell temporarily.
The below infographic presents the differences between hydrodissection and hydrodelineation in tabular form for side-by-side comparison.
Summary – Hydrodissection vs Hydrodelineation
Phacoemulsification is the most common technique used in cataract surgeries. Hydrodissection and hydrodelineation facilitate phacoemulsification easily. Both techniques consist of an injection procedure using a cannula containing a balanced salt solution. Hydrodissection is used during cataract surgery, where the lens capsule separates from the lens cortex. A nucleus rotating easily by the cannula is a sign of a successful hydrodissection. Here, the lens is mobile and detached from the surrounding capsule. Hydrodelineation is a technique used in cataract surgery to separate the outer epinuclear shell from the central endonucleus. This process gives a golden ring or dark circle around the endonucleus, which signifies a circumferential division of the nucleus. So, this summarizes the difference between hydrodissection and hydrodelineation.
Reference:
1. MD, Uday Devgan. “Hydro-Dissection versus Hydro-Delineation.” Cataract Coach.
2. “Hydrodissection and Hydrodelineation.” Moran CORE.
Image Courtesy:
1. “Schematic diagram of the human eye with English annotations” (CC BY-SA 3.0) via Commons Wikimedia