Corneal Degenerations and Ectasias

Degeneration of a tissue is defined as a deterioration that results in impaired structure and function. These changes occur at the cellular level and are caused by biomolecular alterations induced by aging, as well as a wide variety of adverse external and internal influences. Traditionally, degenerations have been classified as involutional (age-related) or non-involutional, depending on type of deposition (hyaline, amyloid, lipid, calcific), and by anatomic location (anterior, posterior, central or peripheral). Degenerations may be unilateral or bilateral, often with asymmetric involvement. Heredity does not play a direct role in these processes. The noninflammatory ectatic diseases of the cornea discussed in this chapter include keratoconus, pellucid marginal degeneration, keratoglobus, and posterior keratoconus. An exceptional degeneration unreported in literature (presumed alimentary cuprum keratopathy) is presented in this chapter. Pseudogerontoxon is one of the characteristic degenerations commonly seen in Middle Eastern populations.

Recurrent Keratoconus. Clinical Case

Purpose: To provide a clinical case of recurrent keratoconus from our practice.Materials and method. A patient came to the clinic with a complaint of decreased visual acuity in the right eye. A series of standard instrumental examinations and Scheimpflug keratotopography were performed, and astigmatism of the right eye was diagnosed. Similar examinations were carried out during the patient’s attendance at follow-up examinations.Results. Based on the results of scanning Scheimpflug keratotopography, the diagnosis of keratoconus (forme fruste) was made. On examination after 1 year, there were no complaints of decreased visual acuity and data from the same instrumental examinations indicating keratoconus. After this examination, the patient came 3.5 years later with complaints of a new decreased visual acuity in the right eye. During instrumental examinations and keratopography, data were obtained indicating the presence of posterior keratoconus. After 1 year, a follow-up examination took place without complaints. The data of instrumental studies are identical to the previous visit; keratotopography revealed a decrease in posterior elevation.Discussion and conclusion. It was revealed that the patient was constantly taking the hydroxyurea drug against the background of systemic disease up to the 3rd visit, at the time of the 4th visit she had not taken it for 1 year. There are publications in the literature on the effect of this type of drugs on the collagen of the dermis of the skin, the type of which corresponds to the collagen of the cornea. We hypothesize that drugs may have an effect on the biomechanical properties of the cornea, which requires further in-depth study.

Acute Transient Macular Edema after Uneventful Cataract Surgery

Purpose: to provide a clinical case of recurrent keratoconus from our practice.Materials and method. A patient came to the clinic with a complaint of decreased visual acuity in the right eye. A series of standard instrumental examinations and Scheimpflug keratotopography were performed, and astigmatism of the right eye was diagnosed. Similar examinations were carried out during the patient’s attendance at follow-up examinations.Results. Based on the results of scanning Scheimpflug keratotopography, the diagnosis of keratoconus (forme fruste) was made. On examination after 1 year, there were no complaints of decreased visual acuity and data from the same instrumental examinations indicating keratoconus. After this examination, the patient came 3.5 years later with complaints of a new decreased visual acuity in the right eye. During instrumental examinations and keratopography, data were obtained indicating the presence of posterior keratoconus. After 1 year, a follow-up examination took place without complaints. The data of instrumental studies are identical to the previous visit; keratotopography revealed a decrease in posterior elevation.Discussions and conclusion. It was revealed that the patient was constantly taking the hydroxyurea drug against the background of systemic disease up to the 3rd visit, at the time of the 4th visit she had not taken it for 1 year. There are publications in the literature on the effect of this type of drugs on the collagen of the dermis of the skin, the type of which corresponds to the collagen of the cornea. We hypothesize that drugs may have an effect on the biomechanical properties of the cornea, which requires further in-depth study.

Posterior keratoconus—clinical aspects and anterior segment optical coherence tomography findings: A case report

Purpose: To describe a case of Posterior Keratoconus (keratoconus posticus); its clinical condition, corneal, refractive response to intracorneal ring implantation (MyoRing), anterior segment optical coherence tomography findings; and micro incisional cataract surgery outcome. Methods: Case report. Results: The case was studied with high resolution anterior segment optical coherence tomography (OCT), epithelium OCT, corneal topography, and aberrometry. A MyoRing was implanted and after the development of cataract, microincisional cataract surgery was performed. A large hyperopic shift was observed following the ring implantation. Calculation of the intraocular lens showed poor predictability. Conclusions: Posterior keratoconus is a rare corneal congenital disorder characterized by a posterior corneal elevation. Surprisingly, on the total corneal aberrometry, the coma is within normal levels; in the anterior and posterior corneal aberrometry, all the low order and high order aberrations are outside of normal parameters. The epithelial thickness is normal on the contrary to anterior keratoconus. Micro incisional cataract surgery can be safely performed in these eyes, although a refractive surprise is expected due to errors in the intraocular lens calculation.

Posterior keratoconus

Posterior keratoconus (PKC) is a rare, typically non-inflammatory condition that is characterised by an abnormal posterior corneal curvature, which may be accompanied by overlying stromal opacification. It is usually congenital and can be associated with other ocular and systemic abnormalities. PKC remains a clinical diagnosis, although imaging techniques including ultrasound biomicroscopy and anterior segment optical coherence tomography may be useful tools for confirmation and classification. Genetic studies should be considered, although no specific genetic defects have been identified thus far. As a potential cause of amblyopia, early diagnosis and management are crucial in maximising visual potential. Occasionally, management considerations may also include surgical intervention, such as corneal transplantation. Intraocular lens power calculation at the time of cataract surgery requires special consideration. Here, we review the present literature on PKC and consider future directions in the management of this rare entity.