READ technology is the newest method to correct presbyopia:
READ technology, which stands for Refractive Enhanced Ablation for Presbyopia, is one of the newest laser methods for treating presbyopia, which is known as the main competitor of the Presbyond method.
What is the main difference between READ and other methods?
In old methods such as "Monovision", one eye was completely adjusted for far and the other eye was completely adjusted for near, which caused a person to have blurred vision in intermediate distances (like working with a monitor). But READ works as follows:
1. Creation of multifocal vision in the cornea: unlike traditional methods, in READ, the surface of the cornea is trimmed in such a way that its curvature becomes "multifocal". This means that each eye alone can cover a range of distances.
2. Improving the depth of focus (Depth of Focus): This technology increases the depth of focus with very precise and subtle changes in the curvature of the cornea so that the transition between far and near vision is very smooth and without "blind spots" or intermediate blur.
3. Precise personalization: This method was developed at the Rothschild Institute in Paris and is designed based on complex mathematical algorithms, exactly according to the eye anatomy of each patient. However, because this operation is performed on the "cornea", if the person has cataracts, doctors usually suggest other methods such as lens replacement (RLE).
To perform surgery with the READ method (abbreviation for Refractive Enhanced Ablation for Presbyopia) using Alcon devices (such as WaveLight EX500), precise technical and software steps must be followed. This work is a specialized protocol that requires the close cooperation of the surgeon and the optometry expert with the software of the device. Next, the step-by-step steps of how to perform this surgery are described: 1. Evaluation and calculation stage (Pre-op)
Before touching the laser device, the patient's data must be entered into the programming software (such as WaveNet or Contoura topography). The goal is to increase the "Depth of Focus" by controlled manipulation of these deviations.
• Calculation of Q-Value: The surgeon changes the \bm{Q} value (curvature coefficient of the cornea) in such a way that the cornea is transformed from a spherical state to a hyper-aspheric state. This makes the light focus on the retina at different points (far and near).
2. Alcon EX500 device settings
In the control panel of the device, the surgeon goes through the following steps:
• Selection of the Ablation Profile: Unlike normal LASIK, which uses a Wavefront Optimized profile, a Customized Aspheric profile is used in READ.
• Entering READ variables: The surgeon manually includes the additional values (Add) required for myopia in the non-dominant eye (or both eyes depending on the protocol).
• Centration: The device must be locked exactly on the optical center (Visual Axis). The smallest error in centering in multifocal methods such as READ can cause glare. 3. The Surgical Process (The Procedure)
Surgery is usually performed by Femto-LASIK method:
1. Creating a flap: using a femtosecond laser (such as Alcon FS200), a very thin layer is lifted from the cornea.
2. EX500 laser radiation: Excimer laser sharpens the cornea according to READ calculations. This cutting is such that the center of the cornea is optimized for near vision and the surrounding areas for far vision (or vice versa, depending on the surgeon's design).
3. Eye-Tracking Technology: The 1050 Hz tracking system of the Elkan device monitors the eye movement every millisecond so that the sharpener is applied exactly in place.
4. Vision strategy (Blended Vision)
In the READ method, the device is adjusted in such a way that:
• Dominant eye: is adjusted for complete far vision (Planus).
• Non-dominant eye: a small amount of myopia (usually between \bm{-1.00} to \bm{-1.50} diopters) remains in it, but with the difference that due to the special sharpening, the quality of far vision of this eye is also It is preserved to a great extent.
Why is this method popular with the Elkan device?
Elkan devices prevent the drying of the cornea during the operation due to the very high speed (500 pulses per second), which is critical in the accuracy of delicate surgeries such as READ. Also, the PerfectPulse system allows the energy of each laser pulse to be controlled so that the surface of the cornea remains perfectly smooth.
Important technical warning
Performing READ surgery is not just about pressing a button on the device. This work requires a software license and the completion of special training courses by the surgeon to know how much "spherical deviation" to induce for each patient so that the person does not experience a loss of quality of vision at night.