Most keratoconus-afflicted people have progressive vision loss but do not become legally-blind. However, corneal scarring is a major predisposing factor for legal-blindness in people living with keratoconus. Ocular (eyeball) trauma can also predispose a keratoconus-afflicted person to progressing to legal-blindness. If you are wondering how to determine if your inadequate eyesight meets the definition of legal-blindness, this classification is applicable if the vision in the “better” eye is 20/200 or worse while utilizing corrective eyeglasses or contact lenses.
Comparing Total Blindness to Legal-Blindness – What is the Difference?
It is possible to still see shapes in your visual field if you have legal-blindness. In contrast, people with total blindness may be unable to even see shapes. The Helen Keller National Center (HKNC) describes total blindness as seeing nothing, or having such limited vision that no useful information about the environment is depicted. Not being able to tell day-time from night-time is an aspect of total-blindness that can contribute to sleep disorders.
According to the Sleep Foundation, total-blindness predisposes to a specific sleep disorder caused by a disturbance in the normal day-time versus night-time perception. In contrast, most legally-blind people can discern whether it is day-time or night-time – even if unable to tell one face from another.
Contact Lenses and Corneal Scarring
Traditional soft and hard contact lenses – due to their small-sized diameters – rest on the cornea. In a keratoconus-afflicted person, wearing traditional contact lenses for several hours may scratch the cornea due to its weakened state (consequent to corneal epithelial thinning). Not everyone living with keratoconus has corneal epithelial thinning, but this is associated with an increasing level of cornea pain and reduced comfort in wearing traditional contact lenses. An abrasion on the cornea can result in permanent corneal scarring, and this can interfere with eyesight by causing blurriness.
The National Eye Institute reports that improper cleaning of contact lenses can lead to an eye infection (termed keratitis), and keratitis is a major cause of corneal scarring. The added risk for someone living with keratoconus is that the resulting scarring may be greater than in someone without some form of underlying cornea disorder, and thereby markedly worsen overall eyesight.
For a keratoconus-afflicted person who experiences discomfort in wearing traditional contact lenses, scleral contact lenses may be preferable. However, corneal scarring may be so severe that the consequence is legal-blindness.
Using a White Cane to Navigate if Legally-Blind
The Perkins School for the Blind website specifies that the customary way the standard white cane is used is called the “Hoover Method”. It involves swinging the cane from side-to-side in a rhythmic pattern before each step to detect unseen obstacles. An advantage of using a white cane (whether totally-blind or legally-blind) is that it can enable other people to recognize that you cannot see things around you. In this way, it can alert people on a busy street to tell you when they are passing you. In a hallway in your workplace and/or school, carrying a white cane with you can also make it easier for you to avoid having a preventable accident.
Corneal Transplants and Legal-Blindness
You may benefit from a corneal transplant if you are keratoconus-afflicted and have progressed to legal-blindness. Although organ rejection may occur – and any organ transplant requires anti-rejection medication for life along with a lifestyle adjustment – corneal transplants actually are successful 98 percent of the time. However, the donor’s cornea must be a “tissue-type” match for you, so you may have to wait for a lengthy period of time until a matching deceased donor’s cornea becomes available for your transplant. This is just one of numerous reasons why preventing legal-blindness – as much as possible – through caring for your eyes is the best approach.
The staff of the Precision Keratoconus Center wants to help you prevent legal-blindness from occurring, and are available to help you understand how to cope with keratoconus symptoms resulting in worsened vision.