OBJECTIVE To study the central corneal thickness of a Spanish population group and determine the influence of age, gender, axial length and refractive error on central corneal thickness (CCT) values. METHODS An observational, cross-sectional, double masked study was conducted on 357 eyes of consecutive Caucasian patients without ophthalmic disease. They were distributed according to age, and ...

PURPOSE To determine the accuracy of a method of calculating intraocular lens (IOL) power after corneal refractive surgery. SETTING Department of Ophthalmology, Hospital de Gipuzkoa, San Sebastián, Spain. METHODS The SRK/T formula was modified to use the pre refractive surgery K-value (Kpre) for the effective lens position (ELP) calculation and the post refractive surgery K-value (Kpost) fo...

BACKGROUND The cornea is responsible for two-thirds of the eye's refractive power which is a function of the shape and refractive index. The aim of this present study is to examine human eyes in vivo for corneal shape changes in response to short-term elevation in intraocular pressure. METHODS Videokeratographic and tonometric assessments at baseline were compared with the same assessments wh...

LASIK (laser-assisted in situ keratomileusis) is a common laser refractive procedure for myopia and astigmatism, involving permanent removal of anterior corneal stromal tissue by excimer ablation beneath a hinged flap. Correction of refractive error is achieved by the resulting change in the curvature of the cornea and is limited by central corneal thickness, as a thin residual stromal bed may ...

The corneal wound healing response following refractive procedures represents a subject of high relevance, due to its direct influence on the postoperative results. Technical modifications of current refractive procedures, like the automated flap creation with the femtosecond laser, LASEK, PRK with mitomycin C and Epi-LASIK have been proposed as alternatives to traditional LASIK and PRK. Severa...

Formulas For Intraocular lens Power calculatIon Modern cataract surgery replaces the natural lens of the eye with an intraocular lens (IOL). After surgery, the optical system of the eye will consist of two major refractive elements, the cornea and the newly inserted IOL. This two-lens system is at the basis of IOL power calculation. To facilitate calculations, both the cornea and the IOL are co...

PURPOSE To test a pseudophakic eye model that allows for intraocular lens power (IOL) calculation, both in normal eyes and in extreme conditions, such as post-LASIK. METHODS PARTICIPANTS The model's efficacy was tested in 54 participants (104 eyes) who underwent LASIK and were assessed before and after surgery, thus allowing to test the same method in the same eye after only changing corne...

Corneal refractive surgeries for the correction of myopia, hyperopia, astigmatism and hyperopia are quick and effective procedures, and have been growing in popularity over the last two decades. However, post-surgery corneal ectasia remains one of the most feared surgical complications. This is where the biomechanical integrity of the cornea begins to fail, with progressive thinning of the stro...

Calculating the surgically induced refractive change following ocular surgery is important for evaluating the results of keratore-fractive procedures, smaller incisions and various wound closures for cataract surgery, and the effect of suturing techniques and suture removal following corneal transplant surgery. We present a ten-step method of calculating the spherical- and cylindrical-induced r...