Epi Contoura – Streamlight

Epi Contoura Streamlight represents a groundbreaking advancement in laser procedures for vision correction. This technique is specifically tailored for patients with thin corneas, providing remarkable results through a procedure that is completely painless, touch-less, cut-less, blade-less, and flap-less.

Photorefractive Keratectomy (PRK) – Touch-less & Supra LASIK Procedures

Unlike LASIK, PRK does not involve creating a corneal flap. Instead, the outer layer of the cornea, known as the epithelium, is entirely removed to reveal the underlying stromal tissue. This layer is essential for protecting the deeper layers of the cornea and maintaining vision. Following this, a laser reshapes the cornea similarly to LASIK. The epithelial layer typically heals within four days, during which the patient is provided with a soft contact lens for protection.

PRK, LASEK, EpiLASEK, and Supra or Touch-less LASIK are categorized as advanced surface ablation (ASA) procedures, all of which avoid creating a corneal flap.

Drawbacks of Surface Laser Procedures

Post Surgery Discomfort

After the removal of the epithelium, patients may experience moderate discomfort for three to five days. This sensation can vary and is often described as pain, discomfort, or a feeling of something foreign in the eye. Although there haven’t been direct comparisons between PRK and Touch-less LASIK, many surgeons agree that post-operative discomfort is quite similar.

Extended Recovery Time

Surface laser procedures necessitate the use of a bandage contact lens for several days until the epithelium fully regenerates. During this healing phase, patients are advised to avoid typical activities, including work and driving, due to impaired vision. While many notice improvements in their vision within days of surgery, full results may take 3-6 months to manifest.

Risk of Corneal Haze

One concern with surface ablation techniques like PRK and Touch-less LASIK is the potential for increased corneal haze, particularly in patients with higher refractive errors. Incomplete removal of epithelial cells can lead to irregular healing, causing visual disturbances that may be distressing.

Higher Risk of Corneal Ulcers

The absence of the protective epithelial layer during the extended healing phase raises the risk of infections like keratitis or corneal ulcers compared to LASIK.

Why Surface Ablations Remain Popular?

Surface ablation may be preferable to LASIK in patients with epithelial basement membrane disease and in patients who have had corneal surgery before, like corneal grafts.

They were thought to offer a distinct advantage in patients with thin corneas, but with new technologies for LASIK, this is no longer true.

Myths Regarding LASIK and ASA (PRK, LASEK, epi LASIK, Supra LASIK) Comparison in Thin Corneas

In fact, in a head to head trail to dispel this myth, Daniel Durrie MD and Stephen Slade MD, compared wavefront-guided thin-flap LASIK (SBK with a femtosecond laser-created 100 micron, 8.5mm flap) and advanced surface ablation in fellow eyes of 50 bilaterally operated patients.

They showed that during follow-up visits through the first month after surgery, the advanced surface ablation procedure was associated with more pain and lower patient satisfaction. Also, the visual outcomes were significantly better in the LASIK eyes on the first day after surgery and remained so for at least three months

The newer LASIK machines like the wavefront-guided LASIK and Contoura Vision Topography Guided LASIK correct the vision based on the eye’s unique attributes and enable the creation of thinner, narrower, and planar flaps, just like femtosecond laser LASIK. These thin flaps allow stromal ablation in even patients with thin corneas with great efficacy and safety. Most doctors agree that thinner flaps (100 µm) have a better postop visual acuity compared with thicker flaps as well. The Contoura Vision Topography Guided LASIK, in fact, provides a better quality of vision than any other laser refractive procedure, in patients with thin corneas also.

Also, most doctors are also now aware of the fact that patients with thinner corneas are NOT more susceptible to ectasia or protrusion of the cornea, since the thinner corneas have altered biomechanics, making them stronger. In fact, the most important risk factor for ectasia is keratoconus (disease and forme fruste) which must be ruled out before any laser refractive procedure. Both LASIK and ASA are contraindicated in patients with keratoconus.