• Description: A bilateral, often asymmetric corneal ectasia with onset during adolescence; causes thinning of the cornea and steep keratometry (a.k.a. cornea is "cone" shaped) leading to blurry vision. Associated with eye rubbing and progresses into the 4th decade of life. 

• Treatment: No treatment but corneal crosslinking can be recommended to slow progression; RGP or scleral contact lenses to improve vision. 

• Emergency?: No but early detection is important to slow progression. 

• Helpful Testing: Topography/tomography, anterior segment OCT. 

• Differential Diagnoses: Pellucid marginal degeneration, corneal ectasia, corneal scarring

Notes:

• Keratoconus is genetic; it is important to educate patients about having family members screened.

• Complications include hydrops, cornea scarring, progressive vision loss. 

• Common symptoms are blurry vision, starbursts in vision, and light sensitivity. 

• Description: A complication of keratoconus in which Descemet's membrane ruptures and aqueous enters the cornea. 

• Treatment: Antibiotic gtt, hypertonic saline solution, consider cycloplegia for pain, consider steroid, discontinue contact lens wear. 

• Emergency?: Yes, extremely painful for patients and can cause corneal scarring which can lead to vision loss. 

• Helpful Testing: Anterior segment OCT, slit lamp photos

• Differential Diagnoses: Corneal scarring, cornea edema. 

• Description: A corneal ectasia in which the cornea thins and bulges (often inferiorly, causing a "kissing dove" appearance on topography). 

• Treatment: No treatment but corneal crosslinking can be recommended to slow progression; RGP or scleral contact lenses to improve vision. 

• Emergency?:No but early detection if important to slow progression. 

• Helpful Testing: Topography/tomography, anterior segment OCT.

• Differential Diagnoses: Keratoconus, post-refractive surgery corneal ectasia. 

Notes:

• The condition is similar to keratoconus in that it is a corneal ectasia that causes blurry vision, starbursts in vision, and light sensitivity. 

• The cornea thinning often occurs at 4:00 and 8:00, causing the "kissing doves" or "crab claw" appearance on tomography.