Classification system aimed at various corneal refractive surgery complications

Dr. Gulani's 5S classifications are an extension of his previous systemization for LASIK.¹ The 5S system proceeds as follows:

"The ability to plan for unaided emmetropia is based on the principle of using the cornea as a platform for visual rehabilitation irrespective of the pathology or the previous surgery," Dr. Gulani said. "The cornea is corrected to final reshaping with the excimer laser for excellent unaided emmetropia."

"A point to remember is that, optically, the posterior opacities may be of little significance in these patients," he said. "Don't focus on chasing the scar; focus on improving the vision."

"This instrument not only allows the ability to study the cornea in three dimensions³ but also enables the clinician to determine the relationship of the cornea to other visually significant anatomy," he said.

Dr. Gulani noted that the use of the imaging technology and 5S Classification System is invaluable for determining which surgical approach to take for keratoconus ranging from form fruste to advanced cases.⁴

In a case of keratoconus with extensive central scarring, treatment for the patient might be deep lamellar keratoplasty to correct the cornea for the central pathology (site) of the opacity (scar) and thickness (strength). By addressing the thickness, he noted, the amount of donor tissue is increased by about 20%, so that there is more tissue to work with later when sculpting this tissue with the excimer laser (shape) to achieve unaided vision (sight).

He described another patient at the other end of the spectrum who underwent epikeratophakia 18 years previously. With a decentered scarred central cornea, the patient had a best-corrected visual acuity of 20/400.