Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report 2 patients who experienced progressive blurring of vision following myopic laser in situ keratomileusis (LASIK) in 1 eye (Case 1) and bilaterally (Case 2). High against-the-rule astigmatism, associated with perilimbal thinning inferiorly, was seen on refraction in all eyes. Regional corneal pachymetry confirmed the peripheral corneal thinning inferiorly. Corneal topography revealed the typical features of pellucid marginal corneal degeneration (PMCD) in the untreated eye of Case 1. Advanced changes were noted in the fellow eye. The corneal topography findings in Case 2 were similar to those seen in PMCD. Patients with early PMCD may present to the refractive surgeon with a stable refraction, normal corrected visual acuity, and adequate central corneal thickness. Corneal topography data along with regional corneal pachymetry must be interpreted carefully to detect these cases. Laser in situ keratomileusis can lead to a rapid progression of PMCD.
 ...
PMID:Keratectasia in 2 cases with pellucid marginal corneal degeneration after laser in situ keratomileusis. 1268 50

The authors suggested the method of intraoperative dot-type keratocompression to localize the zones of ectasia in keratoconus. Corneocompression is made before corneal transplantation under the monitoring of the operation microscope by a special corneocompressor (from the keratoconus top to its periphery). The sagging degree of the examined corneal portion proportionate to its thinning is in the focus of attention. Simultaneously, the ectasia zone is marked by a 1% solution of brilliant green, after which a decision is made on the possibility of its radical incision by trepans of various sizes, ranging from 7.5 to 11 mm. Penetrating keratoplasty was made by using this method in 116 patients (147 eyes) with keratoconus of degrees III-IV according to Amsler. Better refractive results, including a higher visual acuity and a lower degree of postoperative astigmatism in long-term follow-ups ranging from 2 to 12 years, were ensured in the main group (77 patients, 93 eyes) versus the control group (39 patients, 54 eyes). Finally, the authors suggested, on the basis of their own experience, an operational classification of keratoconus.
 ...
PMID:[Penetrating keratoplasty in keratoconus by using the method of intraoperative corneal compression]. 1293 99

Systemic scleroderma is a progressive multi-system connective tissue disease. Ocular involvement includes keratoconjunctivitis sicca, progressive shallowing of conjunctival fornices, peripheral ulcerative keratitis and eyelid tightness. No association has been reported between scleroderma and pellucid marginal degeneration, which is a rare bilateral corneal ectasia. Pellucid marginal degeneration is characterised by non-inflammatory and progressive peripheral corneal thinning inferiorly, often with high against-the-rule astigmatism. We report a case of a 55-year-old woman with systemic scleroderma who presented with rapidly progressing against-the-rule astigmatism. The differential diagnosis of peripheral corneal thinning and the challenge of the surgical management of pellucid marginal degeneration are briefly discussed.
 ...
PMID:Pellucid marginal degeneration and scleroderma. 1518 10

A candidate for refractive surgery presented with classic (type I) Ehlers-Danlos syndrome (EDS). Clinical examination revealed blue sclera, limbus-to-limbus corneal thinning, myopia, and astigmatism. Orbscan (Bausch & Lomb) pachymetry mapping provided a striking demonstration of the limbus-to-limbus thinning with a central corneal thickness of 360 microm in the right eye and 383 microm in the left eye and midperipheral corneal thickness ranging from 370 to 438 microm and 376 to 434 microm, respectively. Despite the theoretical biomechanical weakness from the thin cornea and defective collagen, regular surface topography was maintained without the development of keratoconus. Although all types of EDS remain a contraindication to laser refractive surgery, Orbscan mapping provides a valuable insight into corneal shape and thickness in this condition.
 ...
PMID:Orbscan mapping in Ehlers-Danlos syndrome. 1531 10

A 27-year-old man had excimer photoastigmatic keratectomy in the right eye and laser in situ keratomileusis in the left eye for the treatment of equivalent myopia. Preoperative slitlamp examination did not reveal evidence of keratoconus, central corneal pachymetry was 485 microm in the right eye and 500 microm in the left eye, and corneal topography revealed asymmetric bow-tie astigmatism with inferior steepening in the right eye and a small area of inferior steepening in the left eye. Twenty-two months after surgery, the patient complained of poor vision in the left eye. Slitlamp examination of the left eye revealed central corneal thinning and protrusion, with a Fleischer ring within the flap. Corneal topographic evaluation revealed a stable map in the right eye and central corneal steepening indicative of keratectasia in the left eye.
 ...
PMID:Photorefractive keratectomy versus laser in situ keratomileusis to prevent keratectasia after corneal ablation. 1561 36

Keratoglobus is a rare bilateral condition characterized by a globular protrusion of the cornea. The cornea remains transparent and shows a generalized thinning, most pronounced in the periphery. Most often keratoglobus is a congenital disease, but it may be secondarily acquired. This corneal pathology causes severe visual impairment: it induces extreme myopia, irregular astigmatism, and corneal scarring due to previous hydrops. Spectacle corrections are utilized as long as they provide adequate visual function. Surgery is performed when visual needs are no longer satisfied. However, surgical management of this disease is difficult because of the extreme thinness of the entire cornea. Penetrating keratoplasty is one of the first surgical approaches to have been tested, but it has been partly renounced in favor of more complex procedures. Optimal surgical treatment for keratoglobus remains unknown because of the scarcity of reported surgical results.
 ...
PMID:[Keratoglobus: review of the literature]. 1639 11

Keratoconus is a noninflammatory, progressive disease with ectasia and thinning of the corneal stroma, leading to decrease visual acuity related to asymmetrical irregular astigmatism and myopia. Currently, patients with keratoconus who are contact lens intolerant, are primarily treated by penetrating keratoplasty. When the cornea is transparent, other options may be considered. There are several studies about intrastromal rings implantation, in eyes with keratoconus. The major objective of corneal ring implantation is to reshape the abnormal cornea without removing corneal tissue or touching the central cornea.
 ...
PMID:[Present views concerning surgery treatment of keratoconus]. 1641 14

Orthokeratology (OK) is a clinical technique that uses specially designed rigid contact lenses to reshape the cornea to temporarily reduce or eliminate refractive error. This article reviews the history of traditional daily-wear OK (1960s to 1980s) and discusses the reasons for the recent resurgence in interest in the new modality of overnight OK, using reverse-geometry lens designs (1990s to the present). The clinical efficacy of the current procedure is examined and outcomes from clinical studies in terms of refractive error change and unaided visual acuity are summarised. Onset of the effects of overnight OK lens wear is rapid, with most change after the first night of lens wear and stability of refractive change after seven to 10 days. Mean reductions in myopic refractive error of between 1.75 and 3.33 D and individual reductions of up to 5.00 D have been reported. There appear to be slight reductions or minimal changes in astigmatism with the use of reverse-geometry lenses and most patients are reported to achieve 6/6 unaided vision or better. The induction of higher order aberrations, in particular, spherical aberration, has been reported and this may affect subjective vision under conditions of low contrast and pupil dilation. Patient satisfaction with overnight OK has been reported as similar to or better than with other popular modalities of contact lens wear. Available evidence suggests that the corneal changes induced by overnight OK are fully reversible. The refractive effect in OK is achieved by central epithelial thinning and this has raised concerns about compromise of the epithelial barrier to microbial infection. Recent reports of microbial keratitis in the modality are reviewed and the overall safety of the procedure is examined critically. Recent research on stromal contributions to the OK effect, particularly relating to overnight oedema, is summarised. Emerging issues in OK, including myopic control, correction of other refractive errors and permanency of the OK effect, are discussed.
 ...
PMID:Orthokeratology review and update. 1663 67

Keratoconus is a bilateral, non-inflammatory and progredient corneal ectasia with an incidence of approximately 1 per 2,000 in the general population. Within the second decade of life the cornea develops a conical shape, due to thinning of the corneal stroma with subsequent irregular astigmatism and myopia leading to marked impairment of vision. The most common presentation of the keratoconus is as a sporadic disorder, but it has long been recognized that a significant minority of patients exhibit a family history as an autosomal dominant mode of inheritance. Most investigators suggest complete penetrance of predisposing factors with variable phenotypic expression. In some patients heterozygous mutations in the VSX1 gene are described as the underlying gene defect. An association with Down syndrome, monosomia X (Turner syndrome), Leber's congenital amaurosis, mitral valve prolaps, collagenosis, retinitis pigmentosa and Marfan syndrome is described. The role of corneal cells in the pathogenesis of keratoconus is supported by the published reports of recurrence of keratoconus in eyes after penetrating keratoplasty due to graft repopulation by the recipient cells. Placido-based computeed videokeratographic corneal curvature mapping systems, linked with pachymetry, are useful for identifying overt and subclinical cases of keratoconus. Different indices may quantify the clinical features of keratoconus and may improve the classification. We compared videokeratometric data (Fourier series harmonic analysis and wavefront analysis) in eyes with keratoconus to answer the question of which parameters are useful for early diagnosis of keratoconus.
 ...
PMID:[Keratoconus: epidemiology, risk factors and diagnosis]. 1680 19

The observational case describes bilateral recurrent keratoconus in corneal transplants performed in a patient with self-induced keratoconus secondary to compulsive eye rubbing. Slitlamp findings demonstrated corneal stromal thinning and scarring in the patient's right eye and temporal corneal hydrops in his left eye. Videokeratography of the right eye confirmed the presence of corneal steepening and irregular astigmatism, consistent with the diagnosis of keratoconus involving each transplant. Together with the history of ongoing compulsive eye rubbing, these findings support the concept that chronic mechanical trauma to the cornea may contribute to the development of keratoconus.
 ...
PMID:Bilateral recurrent self-induced keratoconus. 1899 47


<< Previous 1 2 3 4 5 6 7 8 Next >>