From the Guidelines
Keratoconus is the primary corneal condition that causes a cone-like shape, and it is a progressive eye disorder that occurs when the normally round cornea thins and begins to bulge outward into a cone shape, leading to distorted vision. This condition is usually bilateral and varies in severity from clinically undetectable to advanced disease, with eye rubbing, family history, and younger age of onset resulting in greater progression of disease 1. The most common signs of corneal ectasia include inferior steepening, superior flattening, skewing of radial axes on power topographic maps, abnormal islands of elevation anteriorly and/or posteriorly on tomography, and decentered or abnormal corneal thinning or rate of change of corneal thickening from the center to the periphery 1.
Some key points to consider in the management of corneal ectasia include:
- Early treatment options for keratoconus, such as rigid gas permeable contact lenses, scleral lenses, or hybrid lenses, can improve vision 1
- Corneal collagen cross-linking (CXL) is recommended to strengthen corneal tissue and prevent further bulging in progressive keratoconus, typically performed as an outpatient procedure using riboflavin drops and UV light 1
- In severe cases, corneal transplantation (penetrating keratoplasty or deep anterior lamellar keratoplasty) may be necessary, with deep anterior lamellar keratoplasty (DALK) offering advantages such as no risk for endothelial rejection and a low risk of stromal rejection 1
- Other cone-like corneal conditions, such as pellucid marginal degeneration and keratoglobus, can also cause distorted vision and occur due to weakened collagen fibers in the cornea, often with genetic predisposition, and can be exacerbated by eye rubbing or allergies 1
Regular eye exams are essential for early detection of corneal ectasia, as early intervention can significantly slow progression and preserve vision 1. It is also important to note that corneal cross-linking (CXL) reduces the risk of progressive ectasia in patients with keratoconus and stabilizes the corneal, and it is recommended as a treatment option for progressive keratoconus 1.
From the Research
Corneal Conditions that Cause a Cone-Like Shape
- Keratoconus is a bilateral and asymmetric disease that results in progressive thinning and steeping of the cornea, leading to irregular astigmatism and decreased visual acuity 2.
- The condition is characterized by progressive corneal protrusion and thinning, leading to irregular astigmatism and impairment in visual function 3.
- Keratoconus causes ectatic changes in the cornea, resulting in thinning and cone-like steepening, leading to irregular astigmatism and reduced vision 4.
Key Features of Keratoconus
- Progressive thinning and steeping of the cornea 2.
- Irregular astigmatism and decreased visual acuity 2.
- Corneal protrusion and thinning 3.
- Ectatic changes in the cornea, resulting in thinning and cone-like steepening 4.
Diagnosis and Treatment of Keratoconus
- Corneal topography is the primary diagnostic tool for keratoconus detection 2.
- Treatment strategies for keratoconus are tailored to disease severity and progression, and may include vision correction with glasses or soft contact lenses, rigid gas-permeable contact lenses, or scleral lenses 4.
- Corneal collagen cross-linking has emerged as a pivotal treatment aimed at halting the progression of corneal ectasia 5, 4.