By the time this is posted, I will have returned from the local eye hospital, where the progression of an eye condition I have called keratoconus will have been assessed. I have written this before setting off as sometimes the eye examination requires dilation of the pupils and other irritating procedures that can affect one’s vision for several hours, making using a computer difficult.
The condition causes the cornea – the clear, outermost layer of the front of the eye largely responsible for the eye’s ability to focus (by refracting light onto the retina) – to progressively thin, which results in cone-shaped bulging, rather than the usual dome shape of a healthy cornea. This can lead to a range of visual disturbances and symptoms including seeing multiple images or “ghosting” in a single eye, glare or halos around lights, sensitivity to light, and blurred vision. I personally find that ghosting and halos of light to be my most significant symptoms, particularly in situations with high levels of contrast such as when looking at headlights or streetlamps at night, whilst my daytime vision only suffers from blurring that is correctable with contact lenses.
Initially visual impairment can be corrected with glasses, but as the condition progresses one must upgrade to contact lenses; typically soft hydrogel contacts are first used, sometimes upgraded to rigid gas-permeable or large scleral lenses as required, and sometimes two kinds of lenses can be combined, or “piggy-backed”. If even contacts fail to correct vision a range of surgical procedures can be considered, from inserting rings (called Intacs) into the cornea to reinforce it and artificially restore a more dome-like shape to corneal transplants.
Whilst the underlying causes of the condition are poorly understood and as of yet no cures exist, a newer procedure called corneal cross-linking (or CXL) has shown promise for slowing, and even halting, progression of the disease. In CXL a riboflavin treatment and Ultraviolet-A radiation are combined to induce the formation of new bonds between collagen molecules in the cornea to recover and maintain mechanical strength. However, this treatment is only suitable for cases in which the condition is continuing to progress, but has not yet thinned or scarred excessively. If today’s investigations show my eyes as progressively worsening this treatment option may be considered, but we’ll have to wait and see.