Accurate cataract diagnosis requires precise measurements. Learn about optical biometry, slit lamp exams, and how we calculate your new lens power.
Send us all your questions or requests, and our expert team will assist you.
Diagnosing a cataract is relatively simple; any eye doctor can see the cloudy lens during a routine exam. However, evaluating a patient for cataract surgery is a much more complex scientific process. It is not enough to simply remove the old lens; we must precisely calculate the power of the new artificial lens (IOL) that will replace it.
At LIV Hospital, the pre-operative evaluation is the most critical step in your journey. We use a suite of advanced diagnostic technologies to map the unique geometry of your eye. These measurements act as the blueprint for your surgery. If the measurements are even a millimeter off, your vision will not be perfect. Therefore, we dedicate significant time to this “measurement phase” to ensure your visual outcome exceeds your expectations.
Every evaluation begins with the standard Snellen Eye Chart.
This is the microscope used by the ophthalmologist to look directly at the cataract.
Before we operate on the front of the eye, we must ensure the back of the eye is healthy.
Optical biometry is the most important test for planning cataract surgery, measuring the physical dimensions of the eye to calculate the ideal IOL power. LIV Hospital uses devices like the IOLMaster or Lenstar, which use laser light to measure axial length and corneal curvature with precision to 0.01 millimeters. Complex formulas, such as the Barrett Universal II, predict the lens needed for optimal vision. Unlike older ultrasound A-Scans, optical biometry is non-contact, painless, and more accurate.
Corneal Topography
For patients with astigmatism, a 3D map of the cornea is essential. Topography projects rings onto the eye to analyze curvature, identify steep areas, and guide Toric lens alignment for precise astigmatism correction. Without this map, lens placement is only an estimate.
Optical Coherence Tomography (OCT)
OCT uses light waves to capture cross-sectional images of the retina, useful when dense cataracts block the view. It examines the macula for swelling, holes, or membranes, ensuring that premium lenses like multifocals will function properly.
Specular Microscopy
This test evaluates the cornea’s inner endothelial layer, which pumps water out to maintain clarity. Cell counts help assess risk, as cataract surgery can stress these cells. If the count is low, protective measures like viscoelastics are used to prevent corneal swelling.
Preparing for Measurements
Accurate readings require the cornea in its natural shape. Stop wearing soft contacts for one week and RGP lenses for two to three weeks before the exam. Use artificial tears to prevent dryness and bring your current glasses to compare vision changes.
A cataract evaluation usually lasts around two hours and involves multiple scans. The eyes will be dilated, causing temporary blur and light sensitivity, so bring sunglasses and a driver. After testing, the surgeon consults with you on lens options, including Monofocal for distance, Toric for astigmatism, or Trifocal for both near and far vision.
The doctor will explain your refractive target. Emmetropia provides clear distance vision but requires reading glasses. Monovision sets one eye for distance and one for near, reducing dependence on glasses. Multifocal lenses split light for both near and far vision. Test results guide which option your eye can safely support.
Routine cases usually just need Biometry and a Slit Lamp exam. Advanced testing, like OCT or Specular Microscopy, is added if:
Send us all your questions or requests, and our expert team will assist you.
A Slit Lamp Exam detects lens cloudiness. Optical Biometry measures eye length and Keratometry checks corneal curvature to calculate the lens implant power.
Stop wearing contact soft lenses 1 week, hard lenses 2-3 weeks before the exam. Bring sunglasses as your eyes will be dilated.
No, it is painless and non-invasive. You look at a target while the machine uses lasers to measure your eye.
Optical biometry is precise to 0.01 mm, helping achieve the refractive target for clear vision, often 20/20 without glasses.
OCT is used if retinal issues are suspected, such as in diabetes or macular degeneration, to ensure cataract surgery improves vision.
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