Fortnightly Review: Treating myopia with the excimer laser: the present position

Abstract

Summary points Excimer laser photorefractive keratectomy is the latest in a long line of surgical treatments for myopia (short sightedness) Around 50 centres (including three research centres) in the United Kingdom offer this treatment and tens of thousands of patients have been treated worldwide Considerable individual variation in corneal wound healing exists following photorefractive keratectomy, and this limits the predictability of the procedure Predictability of refractive outcome is much better for lower amounts of myopia (up to around - 6.00 dioptres) Important side effects exist which are all more common in people with higher myopia (regression, corneal haze, loss of best corrected visual acuity) Overall patient satisfaction is high and around 85% of patients are pleased with the outcome even if this is a partial correction only Careful patient selection and counselling are vitally important, and all patients must be fully informed of possible side effects

Recent Advances: Ophthalmology

“…Photorefractive keratectomy is a technique of modifying the refractive power of the cornea by laser ablation of the central area, thereby rendering the eye less short sighted 3. Trials of excimer laser photorefractive keratectomy for myopia started in 1989 in Germany and Britain, and later in the United States.…”

Comparable change in stromal refractive index of cat and human corneas following blue-IRIS

“…Photoablation of the stromal bed is typically accomplished via a single-photon absorption mechanism at 193 nm. [1][2][3] This process modifies the cornea's refractive and biomechanical properties and induces additional optical power in the cornea by changing the shape of its anterior surface. However, complications, such as dry eye, 4 stromal haze, 5 diffuse lamellar keratitis, 6 or inflammation 7 can occur from stromal photoablation, epithelial debridement, and/or the creation of the epithelial flap.…”

Treating myopia

“…EDITOR,--David S Gartry's review restores some balance to the debate about photorefractive keratectomy, emphasising that such surgery must be predictable, effective, and safe with a low incidence of complications 1. The excimer laser was introduced to treat myopia in the expectation that photoreactive keratectomy would surpass incisional keratotomy (microsurgery: the safer American development of Russian radial keratotomy) in predictability.…”