Preparing Your Eyes for Cataract Surgery

Biometry is a painless, non-contact measurement process that determines the appropriate power for your new artificial lens, also called an intraocular lens or IOL. The measurements collected include axial length (the front-to-back depth of your eye), keratometry (the curvature of your cornea), and anterior chamber depth (the space between your cornea and your iris).

Modern optical biometry instruments use light to gather this information without touching your eye. The process takes roughly 10 to 15 minutes, and your Cataract Surgeon may repeat the measurements to confirm consistency before finalizing your lens selection.

Corneal topography is a detailed scan that maps the entire surface of your cornea and can detect subtle irregularities or astigmatism that standard measurements might not fully capture. Astigmatism is a common condition where the cornea is slightly curved in an uneven way, which affects how light focuses on the retina.

If you have had previous laser vision correction such as LASIK or PRK, your Cataract Surgeon uses specialized calculation formulas that account for your altered corneal shape. This step is especially important in guiding the choice between standard and premium lens options.

During your preoperative visit, your Cataract Surgeon will dilate your pupils (widen them with eye drops) to examine your retina and optic nerve in detail. This allows us to identify conditions like macular degeneration, diabetic changes, or retinal tears that could limit the vision improvement you experience after surgery.

We also measure your eye pressure using tonometry and examine the drainage structures of your eye to screen for glaucoma. If any findings require attention, your Cataract Surgeon will discuss the appropriate next steps with you before proceeding.

Your Cataract Surgeon will assess your eye surface during the preoperative visit and can repeat measurements if readings vary between sessions. If dry eye or blepharitis is significant, your surgeon may delay biometry until after a short course of treatment. Consistently stable readings across two sessions give your surgeon the confidence needed to finalize your lens power selection.

In most cases, yes. Stopping glaucoma medications without guidance from your doctor can cause dangerous rises in eye pressure that may harm the optic nerve. Your Cataract Surgeon takes your glaucoma drops into account when planning both your surgical approach and your postoperative medication schedule. Always confirm the plan at your preoperative appointment rather than making changes on your own.

Because of fasting requirements, your insulin dose or oral diabetes medication may need to be adjusted on the morning of surgery. Your Cataract Surgeon and primary care physician work together to guide these changes. Stable blood sugar in the days surrounding surgery supports better healing. If you have active diabetic eye disease affecting the retina, your surgeon may want to address that before proceeding with cataract removal.

Biometry and corneal mapping use light and do not touch your eye, so they are entirely painless. Pupil dilation drops may sting briefly and cause temporary light sensitivity and blurry near vision for a few hours, which is normal. Eye pressure checks use either a gentle puff of air or a brief contact with a numbed cornea, and neither causes more than a momentary sensation.

Let your Cataract Surgeon know as soon as possible. Depending on which supplement it is and how close you are to your surgery date, your surgeon may proceed with additional precautions or may adjust your schedule. This is exactly the kind of detail to bring up at your preoperative visit rather than waiting until the day of surgery.

Even with highly accurate modern biometry, a small number of patients may end up needing glasses for certain distances after surgery, which is considered a normal part of the outcome range rather than an error. In rare cases where the lens power is significantly mismatched, options such as an enhancement procedure or lens exchange may be discussed. The preparation steps your surgeon asks you to follow, including stopping contacts on time and treating dry eye first, are specifically designed to minimize this possibility by giving your surgeon the most accurate measurements possible.