CataracTools – Improve your surgery

Sulcus lens calculator

With this tool, you’ll be able to choose the best lens power for the eye of your patient. First, enter the power and the A constant of the lens in the bag, the app will tell you the power of the most common lenses. Alcon MNA60AC, Sensar AR40e and Tecnis ZA9003 are shown by default, but custom lenses are available.

Though the “rule of the nines” is widely used, our calculator offers a more precise approach. Generally speaking, during surgery, we insert the lens with the closest lens power to emmetropia in the bag. When facing sulcus implantation, we have to decrease the power by -0.5, -1 and -1.50 depending on the power lens^1-3. Then, the A constant difference is applied. Therefore, a triple source of error is affecting our decision.

With our app, a custom modification is applied to every single lens power and then the constant difference is applied. However, we’ll always be left with one source of error: choose the lens power with the closest to 0 result. Using the emmetropic value offered by your biometer, you’ll get the most accurate result possible.

Lenses with optics captured by the capsulorexis are expected to have the same power behaviour than lenses in the bag⁴. So, if you intend to capture it, choose the lens on the right column.

Iris Claw Calculator

With this formula, you’ll obtain a quick calculation of the appropriate lens power. You just have to enter the desired lens in the bag power and its constant and the app will automatically give you the suggested iris claw lens power.

Both prepupillary and retropupillary options have been considered and added to the app. However, only Artisan lenses are included by default. Let us know which other lenses you’d like to see included in the app.

IOP correction according to corneal thickness

Features the correction table used for adjusting intraocular pressure based on central corneal thickness (CCT)⁴. This includes just the table. Actually, a searching box and button were considered, but scrolling through the table gives the fastest result.

Biometry lens switcher

Change the lens AFTER the biometry has been done. This calculator takes into account the SRKT constants of the lenses and gives you the new result. If the optimized constant is not available, the nominal A constant will be used and a prompt appears on the screen.

This is specially useful for old biometries or in selected cases when you want to customize the lens for a patient. IOLcon database of lenses has been included here.

Visual acuity conversion

This calculator will assist you when converting visual acuity scales: decimal, Snellen, logMAR and ETDRS.

Treat and Extend scheduler

Easy up your scheduling with this calendar. Designed for treating patient with age-related macular disease and diabetic macular oedema, but feel free to use it for any treat-and-extend schedule you see fit.

Just select a day of the calendar and a variety of dates will show up:
– A 3-month loading phase
– 4, 6, 8, 10, 12… usual periods for your Q4, Q6, Q8… till Q20 and Q24.
– Press on the new date that specific calendar will appear, just in case you want to program custom schedules (2 injections every 10 weeks, for example)

Lens suggestion algorithm for surgeons

One of the least extended behaviours is to optimize and customize the lens selection according to the patients eye.

First, the algorithm will ask for centering results. Pseudoexfoliation, zonular weakness, Marfan syndrome… this conditions represent a higher risk of un-centered lenses. Therefore, an aspheric lens with neutral asphericity correction will provide the higher guarantee of good visual accuity with lower risk.

For other patients, the corneal spherical aberration will be asked, and a lens will be suggested to fix it. You can default to the desired 0.10 residual aberration or input your own. Results around 0.05 and 0.10 provide the best focus – quality balance.