Purpose. To validate clinically a new method for estimating the corneal power (P c ) using a variable keratometric index (n kadj) in eyes with previous laser refractive surgery. Setting. University of Alicante and Medimar International Hospital (Oftalmar), Alicante, (Spain). Design. Retrospective case series. Methods. This retrospective study comprised 62 eyes of 62 patients that had undergone ...

PURPOSE To compare the corneal power measurements obtained using different topographic instruments after myopic photorefractive keratectomy (PRK). METHODS Patients with myopia who were candidates for corneal refractive surgery were sequentially included. Pre-PRK and six months post-PRK corneal powers were measured using Javal manual keratometer, Orbscan II, Galilei, Tomey TMS4, and EyeSys 200...

PURPOSE To describe the different formulas that try to overcome the problem of calculating the intraocular lens (IOL) power in patients that underwent corneal refractive surgery (CRS). METHODS A Pubmed literature search review of all published articles, on keyword associated with IOL power calculation and corneal refractive surgery, as well as the reference lists of retrieved articles, was pe...

BACKGROUND To evaluate and compare the astigmatism prediction errors taken with the Pentacam measurements, Baylor nomogram, and Barrett formula for toric intraocular lens (IOL) implantation. METHODS Phacoemulsification with toric Precizon IOL implantation was performed in 41 eyes with corneal astigmatism (range, 1 to 5 diopters (D)) determined by IOLMaster and SimK on Pentacam. Preoperative c...

There is a long history of corneal refractive surgery. Leonardo Da Vinci in 1508 said the theory of refractive errors. The first systematic analysis of the nature and results of refractive errors came from Francis Cornelius Donders. His classic treatise, “On the anomalies of accommodation and refraction of the eye”, outlined the fundamental principles of physiological optics. Ironically, in thi...

BACKGROUND To examine the influence of posterior corneal astigmatism on postoperative refractive astigmatism in pseudophakic eyes after cataract surgery. METHODS The study enrolled 64 pseudophakic eyes of 50 patients (71.8 ± 9.9 years old, mean ± standard deviation) who had undergone phacoemulsification with non-toric IOL implantation. Refractive astigmatism was measured using an auto ref-ker...

PURPOSE To investigate the association between ocular biometrics such as axial length (AL), anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD) and corneal power (CP) with different refractive errors. METHODS In a cross-sectional study on the 40 to 64-year-old population of Shahroud, random cluster sampling was performed. Ocular biometrics were measured using the A...

For more than 100 years, eye scientists and clinicians have recognized that there is a difference between the refractive and anterior corneal astigmatism of the human eye. Javal postulated an approximately linear relationship between corneal astigmatism and refractive astigmatism, which became known as Javal’s rule: refractive astigmatism 1⁄4 1.25 (keratometric astigmatism) 0.50 90. For most ey...