Keratoplasty for keratoconus: advantages and disadvantages

Keratoconus is a progressive bilateral corneal ectasia, accompanied by loss of vision due to high irregular astigmatism, which is the leading indication for corneal transplantation. The review presents a variety of surgical corneal transplantation techniques for keratoconus available today and discussed their advantages and disadvantages.

Scheimpflug Topography Oriented Adequate Repositioning of a Misaligned Free Flap after Laser in situ Keratomileusis

This report describes a case of Scheimpflug topography oriented adequate repositioning of a misaligned thick free flap after laser in situ keratomileusis (LASIK). A 24-year-old patient consulted for irregular astigmatism and disoriented free right eye flap. The patient previously underwent binocular LASIK at a private clinic. During the right eye surgery, the flap was repositioned after laser ablation due to the free flap. The free flap was not repositioned to its original configuration due to insufficient preoperative corneal marking. On examination, the uncorrected visual acuity was 0.4, and refractive power was +2.00 Dsph with −4.25 Dcyl axis 66 in the right eye. Scheimpflug topography revealed irregular right eye astigmatism. The sagittal curvature of topography showed a 40° counterclockwise misalignment of the steep axis of the cornea. The free flap was repositioned by 40° clockwise rotation. After this, the refractive corneal power improved to −1.00 Dsph with −1.00 Dcyl Axis 19 in the right eye. The uncorrected and best-corrected visual acuity improved to 20/30 and 20/25 (x − 0.25Dsph −1.25 Dcyl A20), respectively. This is the first report on free flap repositioning using Scheimpflug topography. As proper flap positioning was compromised because of the free LASIK flap with no preoperative corneal marking, the flap was effectively repositioned using Scheimpflug topography.

Possibilities of scleral lenses for visual rehabilitation of patients with corneal scars

Purpose. To analyze the efficacy and safety of SCL in patients with corneal cicatricial changes and other concomitant conditions. Material and мethods. The study included 19 patients (20 eyes) with cicatricial deformity of the cornea of various etiology, who were fitted with scleral contact lenses. Results and discussions. The use of SCL is possible in post-traumatic pathology, such as corneoscleral scars with or without aphakia, as well as after keratitis with an outcome in cicatricial deformity, cicatricial changes after a burn. A significant increase in visual acuity compared with spectacle correction has been proven. Depending on the topography of the scar, it is possible to select scleral lenses such as Oblate and Prolate, as well as with different versions of the support zone: both toric and quadratic. Conclusion. Scleral lenses can be successfully used for optical correction in patients with cicatricial changes in the cornea and other concomitant post-traumatic conditions of ineffectiveness of other methods of visual rehabilitation. Key words: cornea, lenses, vision correction, contact lenses, visual rehabilitation, scleral lenses, corneal scars, post-traumatic astigmatism, aphakia, keratitis, toric lenses, quadratic lenses, astigmatism, irregular cornea, regular cornea, regular astigmatism, irregular cornea, irregular astigmatism, prolate, oblate.

Descemet membrane endothelial keratoplasty in a patient with iris-fixated intraocular lens and prior radial keratotomy: a case report

Background Anterior segment surgeries such as cataract surgery, intraocular lens (IOL) repositioning, and radial keratotomy (RK) may hasten endothelial dysfunction, particularly in the context of pre-existing Fuchs dystrophy, necessitating future corneal transplantation. Case presentation A 68-year-old woman with a history of RK with associated irregular astigmatism in both eyes and iris-fixated intraocular lens (IF-IOL) in the left eye presented with six months of decreased vision in the left eye. She was found to have Fuchs dystrophy and underwent DMEK surgery. She had an uncomplicated postoperative course, with uncorrected visual acuity improving to 20/20 three months after surgery. Conclusion To our knowledge, this is the first reported case of a highly successful DMEK surgery in a patient with prior RK and IF-IOL.

Simultaneous transepithelial topographic-guided laser and cross-linking to correct irregular astigmatism in a pediatric patient

Purpose: To evaluate an original approach for treating corneal ectasia and irregular astigmatism secondary to penetrating trauma in a pediatric patient. Case report: An 11 year old patient had a penetrating trauma in right eye when he was two and the refractive error was +1.50 diopters sphere −6.00 diopters cylinder axis 95°. To correct irregular astigmatism, the patient underwent simultaneous transepithelial topographic-guided laser Central Corneal Remodeling (CCR) and Corneal Cross-linking (CXL) in the attempt to regularize corneal ectasia and to improve the quality of vision. Uncorrected and Corrected Distance Visual Acuity were measured using Efficacy and Safety indexes; objective and subjective qualities of vision were evaluated using respectively corneal morphological irregularity index and National Eye Institute Visual Function questionnaires. Conclusions: Twelve month follow up suggests that simultaneous CCR and CXL could be effective to improve the quality of vision and to halt the progression of post-traumatic ectasia in pediatric patients.

Comparison of corneal irregular astigmatism by the type of corneal regular astigmatism

We investigated the relation between corneal regular and irregular astigmatism in normal human eyes. In 951 eyes of 951 patients, corneal irregular astigmatism, such as asymmetry and higher-order irregularity components, was calculated using the Fourier harmonic analysis of corneal topography data within the central 3-mm zone of the anterior corneal surface. The eyes were classified by the type of corneal regular astigmatism into four groups; minimum (< 0.75 diopters), with-the-rule (WTR), against-the-rule (ATR), and oblique astigmatism. The mean age was significantly different among the four groups (P < 0.001); patients with WTR astigmatism were the youngest, followed by those with minimum, oblique, and ATR astigmatism. Significant inter-group differences were found among the four groups in asymmetry (P = 0.005) and higher-order irregularity components (P < 0.001); the largest was in eyes with oblique astigmatism, followed by ATR, WTR, and minimum astigmatism. The stepwise multiple regression analysis revealed that corneal regular astigmatism pattern significantly influenced the amount of corneal irregular astigmatism after controlling for confounding factors (P < 0.001). Corneal irregular astigmatism, such as asymmetry and higher order irregularity components, was the largest in eyes with oblique astigmatism, followed by those with ATR, WTR, and minimum astigmatism, even after adjustment for age of subjects.

Comparison of Amsler–Krumeich and Sandali Classifications for Staging Eyes with Keratoconus

Keratoconus (KC) is the most common corneal ectasia characterized by progressive corneal thinning, protrusion, and irregular astigmatism. The Amsler–Krumeich classification based on the analysis of corneal topography, corneal thickness, refraction and biomicroscopy is the most commonly used; recently, a new classification based on anterior segment Optical Coherence Tomography was introduced by Sandali and colleagues. Since there is no information about the possible agreement between these two classifications, the aim of this study is to compare the stratification of consecutive KC patients using the Amsler–Krumeich and Sandali classifications, and to further ascertain KC cases in which one classification is preferred over the other. Overall, 252 eyes of 137 patients (41.45 ± 16.93 years) were analyzed: in 156 eyes (61.9%), the Amsler and Sandali staging differed in one stage while in 75 cases (29.8%) it differed in two or more stages. In 222 eyes (88.1%), the Sandali staging was higher compared to the Amsler one. These results show that the two classifications are not fully interchangeable: the Amsler–Krumeich classification is more appropriate in identifying and longitudinally monitoring patients with early stages of KC, while the Sandali classification for the diagnosis and follow-up of patients with more advanced stages, particularly when a surgical planning has to be chosen.