Related Experiment Video
Updated: May 21, 2026
05:14
Comparison of Agreement and Accuracy using Binocular Wavefront Optometer with Autorefractor and Phoropter
Published on: September 16, 2025
Intraocular lens power calculation after corneal refractive surgery
Mohammad-Ali Javadi1, Sepehr Feizi, Parviz Malekifar
1Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Journal of Ophthalmic & Vision Research
|June 28, 2012
Summary
Phacoemulsification with intraocular lens implantation in eyes with prior refractive surgery achieved comparable refractive outcomes. A novel method for calculating intraocular lens power proved simple and effective.
Area of Science:
- Ophthalmology
- Refractive Surgery
- Cataract Surgery
Background:
- Previous corneal refractive surgery, such as photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK), can complicate cataract surgery planning.
- Accurate intraocular lens (IOL) power calculation is crucial for achieving desired refractive outcomes after phacoemulsification (PE).
Purpose of the Study:
- To evaluate the refractive results of phacoemulsification (PE) and posterior chamber intraocular lens (PCIOL) implantation in patients who have undergone prior myopic corneal refractive surgery.
- To assess a new method for calculating IOL power in this specific patient population.
Main Methods:
- A retrospective study included 18 eyes of 14 patients with prior PRK or LASIK who underwent PE+PCIOL.
- Computerized corneal topography was used to determine central keratometry for IOL power calculation with the SRK/T formula.
- A modified approach involved selecting an IOL power 1 D greater than the calculated value.
Main Results:
- The mean implanted IOL power was not significantly different from the target refraction.
- Postoperative spherical equivalent refractive error was comparable to the intended refraction.
- Achieved refractive outcomes were within ±1.0 D in 61.1% of eyes and within ±2.0 D in 88.9% of eyes.
Conclusions:
- The proposed method for IOL power calculation is simple and does not require pre-refractive surgery data.
- This approach yields refractive outcomes comparable to established methods for eyes with prior keratorefractive surgery.
Related Concept Videos
01:16Focusing of Light in the Eye
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
01:28Angle Closure Glaucoma: Treatment
Angle-closure glaucoma, or closed-angle glaucoma, is an eye condition where the iris bulges out and blocks the iridocorneal angle, resulting in a buildup of aqueous humor and increased intraocular pressure. Immediate medical attention is necessary due to the sudden onset of symptoms. The treatment for angle-closure glaucoma includes short-term and long-term approaches. Short-term treatment involves using eye drops like pilocarpine to lower intraocular pressure by increasing aqueous humor...
01:27Open Angle Glaucoma: Treatment
In open-angle glaucoma, the iridocorneal angle remains open, but the trabecular meshwork becomes stiff, slowing down the outflow of aqueous humor. This causes a buildup of aqueous humor in the anterior chamber, leading to a sudden increase in intraocular pressure. The treatment for open-angle glaucoma focuses on reducing the elevated intraocular pressure by either decreasing the secretion of aqueous humor or increasing its outflow.
Drugs such as carbonic anhydrase inhibitors, α2- and...
Drugs such as carbonic anhydrase inhibitors, α2- and...
01:25Glaucoma: Overview
Glaucoma is an eye condition characterized by increased intraocular pressure that damages the retina and optic nerve, leading to irreversible blindness if left untreated. The human eye has various components, including the cornea, iris, pupil, lens, and optic nerve. Aqueous humor is secreted by the epithelium of the ciliary body in the posterior chamber and flows through the trabecular meshwork and canal of Schlemm, maintaining normal intraocular pressure. The trabecular meshwork and the canal...