Comparison of visual performance between two extended depth-of-focus intraocular lenses: the novel aspheric hybrid diffractive bifocal-based design versus wavefront-shaping
This prospective study comparing two extended depth-of-focus intraocular lenses found that while both provide good distance-to-intermediate vision, the hybrid aspheric diffractive bifocal-based AMEUH offers superior functional near vision and near satisfaction, whereas the wavefront-shaping DFT015 provides better intermediate acuity, suggesting that patient selection should be tailored to specific visual priorities.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
For millions of people, the clouding of the eye's natural lens, known as a cataract, is a barrier to seeing the world clearly. Modern surgery removes this clouded lens and replaces it with a permanent artificial one. In the past, the goal was simply to restore sight. Today, the aim is to restore a full range of vision, allowing people to see distant landscapes, read a menu at a restaurant, and check a smartphone without constantly swapping glasses. To achieve this, surgeons use special lenses designed to extend the depth of focus, a concept that allows the eye to keep objects sharp at multiple distances simultaneously. While some of these lenses split light to create two or three focal points, others use subtle changes to the shape of light waves to stretch a single focus into a continuous range. The challenge for eye surgeons is choosing the right tool for each patient, as different designs offer different strengths and weaknesses.
A team of researchers in China recently set out to compare two specific types of these advanced lenses to see how they perform in real patients. One lens, known as the AMEUH, uses a hybrid design that combines a smooth, aspheric surface with a series of microscopic rings on the back. These rings act like a bifocal, adding power for near vision, while the front surface helps smooth out the transition between distances. The other lens, the DFT015, relies on a different approach called wavefront shaping. Instead of splitting light or adding rings, it gently reshapes the light waves passing through the center of the lens to stretch the focus without creating the optical side effects often seen in older designs. The researchers wanted to know which of these two distinct technologies provided better vision for distance, intermediate tasks like computer work, and close-up reading.
The study followed 73 patients who underwent cataract surgery at a hospital in Chongqing. The patients were divided into two groups based on their preference and the surgeon's recommendation: 37 received the hybrid AMEUH lens, and 36 received the wavefront-shaping DFT015 lens. The surgeons aimed to leave the patients with a natural focus for distance, meaning no glasses would be needed for far-away objects. Six months after the operation, the team measured how well the patients could see at various distances, how sensitive their eyes were to contrast in different lighting, and how satisfied they felt with their vision in daily life. They also asked the patients about any visual disturbances, such as halos around lights or ghost images.
The results showed that both lenses were highly successful at restoring clear distance vision. Patients in both groups could see far away with equal sharpness, and their ability to distinguish objects in low light or with glare was also comparable. However, the two lenses began to diverge when it came to intermediate and near vision. The patients with the DFT015 lens saw slightly better at an intermediate distance of about two feet, which is the typical distance for a computer screen. In contrast, the patients with the AMEUH lens saw significantly better at a near distance of about 16 inches, which is the standard distance for reading a book or a phone.
This difference was reflected in the patients' daily experiences. While everyone was happy with their distance and computer vision, those with the AMEUH lens reported much higher satisfaction with their ability to read without glasses. Nearly 90 percent of the AMEUH group said they did not need glasses for reading, compared to only about 42 percent of the DFT015 group. The researchers also calculated the total area of clear vision across all distances and found that the AMEUH lens provided a broader range of usable vision overall, particularly in the near zone. Despite having a design that includes rings to help with near vision, the AMEUH lens did not cause more visual disturbances than the other lens; reports of halos or glare were rare and mild in both groups.
The study suggests that while both lenses are excellent choices for restoring distance and intermediate vision, they cater to slightly different needs. The wavefront-shaping DFT015 lens appears to be a strong option for patients who prioritize clear vision for computer work and intermediate tasks. The hybrid AMEUH lens, with its ability to provide superior near vision, seems better suited for patients who have high demands for reading and close-up work. The researchers noted that the choice between the two should depend on what the patient values most, as each design involves a different balance of optical benefits. The findings offer a clearer picture for surgeons and patients navigating the complex world of modern cataract surgery, helping to match the right lens to the right lifestyle.
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