What You Must Know Before Cataract Surgery: The Comprehensive Pre-Op Examination Process

A Reassuring Guide from BGN Eye Clinic, Jamsil Lotte World Tower

Hello, this is BGN Eye Clinic, Jamsil Lotte World Tower.

This is actually my very first blog post, and I have to admit — I'm a little nervous. I kept thinking about what to write first, and the first thing that came to mind was my own grandparents. My grandfather watches the TV news and says, "The subtitles are so blurry, I can barely read them," and my grandmother laughs while doing needlework and says, "I can't even see the eye of the needle — so frustrating!" As we get older, these kinds of difficulties are something everyone goes through.

In fact, the most common cause of these symptoms is cataracts. Whenever I hear these conversations at home, I think to myself, "That's exactly what my patients say in the clinic."

But when patients come in and go through the examination, many of them are surprised. "Why does the exam take so long?" "Isn't some of this unrelated to cataracts?"

That's why, in this first post, I'd like to walk you through the comprehensive pre-operative examination process that is essential before cataract surgery — so that everyone preparing for it, including grandparents and family members, can feel a little more at ease.

The Start of the Comprehensive Cataract Exam: Visual Acuity and Intraocular Pressure Tests

The first steps in preparing for cataract surgery are the visual acuity test and the intraocular pressure (IOP) test. Many patients ask, "It's just cataract surgery — why do we need to start with these basic tests?" But in reality, these two steps are critical enough to influence the outcome of the surgery.

Why the Visual Acuity Test Matters

Cataracts cause the lens to become cloudy, resulting in blurred vision — but we need to accurately measure your current corrected vision in order to set a target vision for after surgery. For example, whether you want to live without glasses after the procedure, or whether you prioritize clear distance vision, the surgical plan changes accordingly. That is why measuring visual acuity must always come first.

The Meaning of the Intraocular Pressure Test

Another critical step is the intraocular pressure (IOP) test. This isn't just a routine check — it's an essential process to determine whether glaucoma is also present. If both cataracts and glaucoma exist simultaneously, the recovery timeline and management approach after surgery will be different. Therefore, IOP testing is a must to thoroughly assess the condition of the eye before cataract surgery.

The Pentacam is a device that uses 3D imaging to analyze the anterior segment and cornea of the eye. It is especially used in pre-refractive surgery exams and comprehensive pre-cataract surgery evaluations.

The Core of the Comprehensive Exam: Dilated Pupil Examination

One of the most important steps before cataract surgery is the dilated pupil examination (mydriasis test). Because the pupil must be artificially widened to allow thorough observation of the retina and optic nerve, this is an indispensable core step in the comprehensive cataract exam.

Why the Dilated Pupil Exam Is Necessary

Cataracts cause the lens to become cloudy and vision to blur — but we must also confirm that there are no problems with the retina or optic nerve behind it. If conditions such as macular degeneration or diabetic retinopathy are present in the retina, cataract surgery alone may not achieve the desired vision recovery. Therefore, the dilated pupil examination is essential to accurately predict surgical outcomes and improve safety.

Possible Discomfort During the Exam

After dilation drops are administered, it takes approximately 30 minutes for the pupil to fully open. Additionally, for several hours afterward, patients may experience light sensitivity and glare, making driving difficult. Some patients ask, "Can't we just skip this part?" — but because it is directly tied to the success of the surgery, it absolutely cannot be omitted.

Essential Steps: OCT and Fundus Examination

There are two procedures that must be completed during the pre-cataract surgery exam: the OCT (Optical Coherence Tomography) test and the fundus examination (retinal exam). These tests allow us to thoroughly examine the retina and optic nerve deep inside the eye.

Many patients think, "Cataracts just cloud the lens — so if you swap it out, that's the end of it, right?" But in reality, that's not the case. To achieve clear vision after surgery, the health of the retina must also be in good condition. These tests are highly significant because they can also detect hidden eye diseases at an early stage.

The Key to Successful Cataract Surgery: IOL Power Measurement (IOL Master)

Cataract surgery doesn't end simply with removing the cloudy lens. The true key lies in how precisely the replacement intraocular lens (IOL) is calibrated. This is where IOL power measurement — performed using advanced equipment such as the IOL Master — comes in.

The patient's axial length (the length of the eye), corneal curvature, and degree of astigmatism are precisely analyzed to calculate the best-fit custom lens for that individual eye. This determines whether a monofocal or multifocal lens is appropriate, and ultimately shapes the patient's quality of daily life after surgery.

Things Patients Often Overlook in the Pre-Cataract Exam

• No Driving: After pupil dilation, driving is not possible. Please come with a guardian or use public transportation.
• Overall Health Check: Because the exam process also checks for glaucoma and retinal disease, it provides important data connecting eye health to overall physical health.
• Disclose Underlying Conditions: If you have diabetes or high blood pressure, please be sure to inform your medical team. It directly affects the surgical plan.

"Do I Really Have to Do All of This?" — A Patient's Story

Not long ago, we had a patient in her 70s visiting us for the first time. While waiting for her dilated pupil exam, she said with a tired expression, "If just the tests take this long, how hard must the surgery be? Do I really have to do all of this?"

I sat down beside her and explained calmly: "The more carefully we check things now, the safer the surgery will be — and the better the results." During the examination, early signs of a retinal abnormality were discovered, which allowed us to adjust the surgical plan and ensure a stable recovery. I still clearly remember the moment when she and her daughter walked out smiling and said, "So there was a reason for all of it."

Cataract surgery cannot be undone once it is performed, which is why the pre-operative comprehensive examination is the most important part of the entire process. Even if it feels a little tedious, undergoing a thorough exam is what allows you to expect a satisfying vision recovery after surgery.

At BGN Eye Clinic Jamsil Lotte World Tower, we use state-of-the-art equipment and a systematic examination protocol to carefully design a surgical plan perfectly tailored to each patient's eyes. The safest first step toward your eye health starts with a comprehensive examination.