وصف
Keratoconus is a progressive eye disorder that affects the cornea, the transparent front part of the eye. The condition is characterized by the cornea gradually thinning and bulging into a cone-like shape, leading to distorted vision. Keratoconus often begins during the teenage years and progresses slowly over time. Common symptoms include blurred or distorted vision, sensitivity to light, and increased nearsightedness or astigmatism. The exact cause of keratoconus is not fully understood, but genetic and environmental factors may contribute to its development. Early stages of keratoconus can be managed with glasses or contact lenses, but advanced cases may require surgical intervention. In severe cases, a corneal transplant may be recommended to restore clear vision. Regular eye exams are crucial for detecting and monitoring keratoconus, especially in individuals with a family history of the condition.
ملخص
- Keratoconus is defined as an ectatic corneal dystrophy involving central or paracentral corneal thinning, leading to irregular myopic astigmatism. It often presents bilaterally, with varying severity between eyes, and typically emerges in the second decade of life. Factors like contact lens use, UV exposure, and eye rubbing are associated with its progression.
- Histologically, keratoconus affects all corneal layers, causing thinning and microscopic alterations. Early changes occur in the epithelium, while advanced cases exhibit Bowman's membrane dystrophy and breaks, leading to linear scars (Vogt's striae). Corneal topography, particularly video-keratography, is crucial for diagnosis, revealing subclinical and clinical forms classified by cone location and morphology.
- Management aims to halt progression with corneal cross-linking (CXL), which strengthens the cornea using riboflavin and UV light. CXL is indicated for progressive disease with sufficient corneal thickness and limited scarring. Spectacles and soft contact lenses can manage early cases, while rigid gas permeable (RGP) lenses offer better vision correction by masking corneal irregularities.
- Intracorneal ring segments (ICRS) reshape the cornea to improve vision and facilitate better spectacle correction. Different ring types exist, and femtosecond lasers enhance precision in tunnel creation. However, ICRS primarily reshape the cornea, requiring subsequent correction with glasses or contact lenses.
- Keratoplasty, or corneal transplantation, involves replacing the diseased cornea with donor tissue. Penetrating keratoplasty replaces the entire cornea, while lamellar techniques replace only specific layers. DALK (Deep Anterior Lamellar Keratoplasty) minimizes rejection risk. Post-operative management includes steroid use and addressing astigmatism.
- Phakic IOLs (Intraocular Lenses) can be considered after keratoplasty, CXL, or ICRS to further refine vision. Careful follow-up is essential for keratoconus patients, and a combination of treatments might be necessary to address both corneal weakness and refractive errors.
نموذج شهادة
حول المتحدثين
د. تامر جمالي
جراح القرنية وتصحيح البصر، مستشفيات مغربي، الإمارات العربية المتحدة
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