Containment of keratoconus and other abnormally shaped corneas

July 1, 2010

An holistic approach that focuses on the healthy part of the cornea.

If you take topographical mapping across the keratoconic cornea, you will see the inferior cornea is invaginated or dimpled in (steeper in curvature), pushing the central and superior cornea out. It is always bilateral, but one cornea is more advanced than the other. Dr Bronstein felt keratoconus was a redistribution of the pressure and not just an ectasia of the cornea, and said the central ring will be pointed or oblong, not round. If you look straight ahead and put your index finger on your lower lid and press in you have induced a close topography of keratoconus, in my opinion. Why not match or align the aspheric corneal shape with an ARGP?1

If you fit soft or soft silicone hydrogel lenses, which curvature are you looking at? Which part of the cornea is diseased and dying and which area is alive and healthy? Do we, as clinicians, preserve and enhance what is living and ignore what is dying? Do we focus on the disease (central Ks) and run the risk of pinching off or peripherally sealing off the healthy and flatter superior cornea with steeply fit spherical RGPs with apical clearance or alignment? Do soft contacts or steeply fit spherical RGPs seal off, or suck onto, the superior quadrants of these aspheric corneas, helping to invaginate the inferior cornea, induce oedema, and trap old tears carrying out waste products such as lactic acid, carbon dioxide, and dead cellular debris? With very high oxygen permeable contacts (soft or rigid), is this what causes the central stippling, 3-9 staining, vertical folds, we see in apical clearance or apical alignment fits? My teachers, Dr Bronstein and Iacono, impression was 'yes.' In soft silicone hydrogel fits, look at the amount of neovascularity you are inducing on the whole cornea. Does this induce a steep cone and more myopia on pseudocones (distorted corneas) from tight-fitted contacts and poor refractive surgery results? Are the discomfort and reduced wearing time caused by not looking at and fitting the whole cornea and not managing the patient in a holistic manner? Is 3-9 staining just from poor blinking or an RGP fit that is too steep or tight? Is it just looking at design from keratometry readings giving you central Ks and not fitting aligned to the 9th ring flatter periphery? Dr George Iacono said this is: "Just fitting the 3 mm island," and added, "we all know what happened to Three Mile Island."