Secure Control of Eye Position

During surgery, patients may have difficulty keeping their eyes from moving.

Conventional LASIK - In conventional LASIK, fixation of the patient’s eye may or may not be provided for. If fixation is provided for, the conventional fixation tools utilized do not downsize and simultaneously provide for containment of the delicate and highly absorbent flap and stromal bed tissues.

Excessive eye movements during LASIK can cause several problems including:
• Mechanical rubbing of the delicate flap/corneal bed tissues against the lid speculum. (Illustration 8)
• Inaccurate placement of laser beam
• Inadvertent contact of the flap and flap bed with pooling cul de sac fluids, lid margins and lashes resulting in possible contamination.
• Prolongation of the procedure
• Change in hydration status form contact with lid margin and cul-de sac fluids.
• Added manipulations to reposition and fixate the flap back into position.

Although some lasers have incorporated trackers to follow eye movements the tracking technology has limitations. One of these limitations is that there will always be a critical delay between measurement alignment and delivery. Even if the tracker has a sampling rate as fast as 4,000 times per second, time is still needed to adjust the laser mechanics and optics so that the energy is delivered to the predetermined position on the cornea. However during a latency period of 10 milliseconds, the normal eye can move up to 19mm . Another limitation of trackers results from large eye movements which cause a temporarily shut down of the laser treatment delivery. These delays may result in changes in hydration of the target tissue thereby resulting in non-standardization of the laser ablation rate. Researchers have proven the need for laser refractive surgeons to minimize changes in surface hydration status of the ablating corneal tissue to maximize the predictability of excimer laser photo refractive procedures . A third limitation of trackers may be the "false sense of security" created causing some to take a "back seat" approach to the laser delivery step of Stage II.

LAHayeSIK™ Surgical System - The conformed fit of the LAHayeSIK™ Handpiece provides a means of controlling the patient’s eye movements relative to the Handpiece while concurrently containing the surgical field. LAHayeSIK™ is designed to minimize eye movements and inadvertent contact of the open delicate surgical tissues to the conjunctiva, lid margins, lashes, lid speculum, drape edges, and cul de sac fluids, which may lead to contamination, mechanical abrasion, and change in hydration status affecting laser effectiveness and overall delay in the procedure. (Illustration 9)

It is the opinion of some researchers and LASIK physicians that the combination of ocular fixation with laser trackers may provide an added advantage. LAHayeSIK™ is well matched with most eye trackers.

Patients also find comfort in knowing that they do not have to worry about trying to keep their eyes steady during their operation.

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