For IOL placement, location is key
Alternative method ensures lens is set properly during cataract surgery
Special to Ophthalmology Times©
The value of lens alignment technology for toric
However, a topic that is not as prevalent is how surgeons ensure that a multifocal IOL is centered on the visual axis during
Related:
Herein, I will share how I utilize lens alignment technology, not only for toric markings but also to verify the visual axis for multifocal lens implantation.
This approach has become critical for me to confirm proper placement and help decrease postoperative adverse events.
Finding the center of the visual axis
As cataract surgeons, we try to do our best at controlling variables so that we have more predictability with our outcomes.
As such, there are many preoperative tools at our disposal, including topography, aberrometry, ray tracing, or various alignment systems.
However, intraoperatively, only recently have we discovered an efficient way of applying the preoperative data we have collected and using them in the operating room.
Related:
Aberrometry has also been used intraoperatively, but its benefit is in the lens power and alignment of a toric
My colleagues and I have a variety of technologies that provide
Although we have an incredible amount of preoperative data, in surgery, we often find ourselves still guessing or “eyeballing” the placement of the lens.
For instance, in the past, we have used the Purkinje reflex of the microscope to align and center the lens, which can be affected by patient gaze. We often centered the lens based on the pupil.
However, if the pupil is irregular, we may not be placing it in the center of the visual axis, and some patients have a high-angle kappa or chord Mu (average chord mu, 0.2 ± 0.11 mm) where the center of the visual axis is not at the center of the pupil.
Related:
As a result, patients can have up to 0.5 mm to 0.6 mm of difference between the center of the pupil and the center of the visual axis.
Furthermore, if a patient has irregular or dilated pupils, it interferes with the ability to judge the location of the center of the visual axis due to the distorted pupil and iris.
An alternate approach
What I have found revolutionary about using a biometer with lens alignment technology (IOLMaster 700; Carl Zeiss) and a digital marking system (Callisto eye; Carl Zeiss) is that it allows me to use preoperative data and apply them intraoperatively to help position the lens in an efficient and consistent way.