Clinical Research Directory

Improving Visual Quality in Patients With Irregular Corneas Using Asymmetrical Toric Intraocular Lenses

Cataract surgery in patients with irregular corneas presents unique challenges, primarily due to the high variability in keratometry and corneal tomography measurements, which complicates accurate intraocular lens (IOL) calculations. In these patients, therapeutic options are currently limited to either non-toric IOLs and rigid contact lenses postoperatively or conventional toric IOLs for the reduction of total astigmatism within cataract surgery. While conventional toric IOLs may be beneficial in selected cases with a stable astigmatic pattern and clear axis, their effectiveness is largely limited, as significant irregularity and higher order aberrations reduce predictability, accuracy of formulae, and refractive outcomes. Therefore, the development of a reliable method to reduce total astigmatism - including irregular components - would represent a major advancement, potentially improving both visual function and patient quality of life. The aim of this exploratory study is to evaluate the effectiveness of customized toric intraocular lenses (AMILens Individual, AMIPLANT GmbH, Germany) in reducing total corneal astigmatism in patients with a significant irregular astigmatic component. These lenses are designed to address corneal aberrations up to the 6th Zernike order, thereby extending correction beyond the capabilities of conventional toric IOLs. To our knowledge, no clinical study has yet investigated this novel approach.

Effect of Corneal and Scleral RGP Lenses on Ocular Health and Visual Quality in Keratoconus

This study aims to compare the ocular health and visual quality of corneal rigid gas permeable lenses (CRGPL) and scleral rigid gas permeable lenses (SRGPL) for patients with keratoconus in a crossover clinical trial. The study will analyze subjective and objective outcomes, including best corrected visual acuity, contrast sensitivity, higher-order aberrations and subjective perception of visual function and comfort. It will also investigate the impact of both lens types on the health of the ocular surface, including evaluation of corneal, conjunctival, and scleral tissues, and tear film. Only one randomized controlled trial has compared the effect of CRGPL and SRGPL wear for patients with an ectatic corneal disorder. With the increasing popularity of SRGPL, examining the differences in efficacy, safety, and patient-reported outcomes between the two types of lenses is increasingly relevant.

Intrastromal Fresh Human Corneal Lenticule Implantation Using Smile Surgery for Treatment of Irregular Corneal Astigmatism After Penetrating Keratoplasty (new Approach)

The aim of the study is to present the effect of implanting intrastromal fresh corneal lenticule by SMILE surgery as a new method-approach to correct the corneal shape on purpose to reduce irregular astigmatism and increasing visual acuity after penetrating keratoplasty.

Wavefront Guided Scleral Lenses for Keratoconus and Irregular Astigmatism

Aberrations are the spreading of light from a point focus. Aberrations of the eyes can be objectively evaluated with a wavefront aberrometer. Lower order aberrations such as defocus and astigmatism can be corrected with glasses and traditional/disposable soft contact lenses. Patients with ectatic corneal disease, such as keratoconus, or irregular astigmatism cause by surgery, trauma or disease, experience vision that is unlikely to be adequately corrected with glasses or disposable soft contact lenses due to higher order aberrations (HOA). HOA's cause halos, flare, glare, starbursts, doubling, smearing or ghosting of vision. Specialty contact lenses, such as scleral lenses, can be used to mask the irregularity of the cornea, reducing HOA's and improving vision. In many patients the resultant vision, though improved, still has some level of residual HOA's affecting the quality of vision. Custom scleral lenses with customized wavefront guided optics can be used to reduce residual HOA's and improve vision further. These lenses have been referred to as higher order aberration correcting scleral lenses or HOA correcting sclerals and wavefront guided scleral lenses or WFG sclerals.