Algorithm addresses corneal scarring

November 30, 2011

An algorithm for addressing corneal scarring might avoid the need for most corneal transplantation procedures by using the law of optics for optimally shaping the front surface of the cornea. Arun Gulani, MD, MS, uses refractive PRK to treat corneal scars and explained how his system works.

Jacksonville, FL-An algorithm for addressing corneal scarring might avoid the need for most corneal transplantation procedures by using the law of optics for optimally shaping the front surface of the cornea. Arun Gulani, MD, MS, uses refractive PRK to treat corneal scars and explained how his system works.

“Despite the elegance and the minimalistic approaches of modern-day transplantations, they rarely result in emmetropic outcomes,” said Dr. Gulani, founding director and chief surgeon, Gulani Vision Institute in Jacksonville, FL.

“This made me apply Corneoplastique principles using the 5S system algorithm-sight, scar, shape, strength, and sight-to take a corneal scar straight to vision,” he said. “All principles of laser Corneoplastique surgery are maintained (i.e., the procedures are topical, brief, esthetically pleasing, and visually promising).”

Dr. Gulani explained that he developed Corneoplastique, a protocol that utilizes a spectrum of surgical techniques, to address the challenging issues that these patients present. He teaches the application of laser PRK for these cases and explained his rationale for that choice.

“The shape of the cornea decides the refractive status,” Dr. Gulani said. “Why not use this knowledge along with the principles of optics wherein, if the anterior lens surface (of a lens of certain thickness, in this case, cornea) is a perfect shape, it overrides and decreases the impact of the posterior irregularities in shape or clarity.

“Laser PRK shapes the cornea and as a side effect removes the scar or moves it more posteriorly into the corneal thickness,” he added. “Many patients see 20/20 despite the presence of a residual scar. Unlike laser phototherapeutic keratectomy, which addresses the scar but might distort the vision, PRK aims for vision despite the scar.”

Dr. Gulani teaches his fellows to chase the SHAPE not the SCAR.

The PRK procedure performed is a standard technique with mitomycin C. He uses the 5S system for almost all his patients to achieve an unaided emmetropic outcome, he explained.

“The scar is an important part of the system,” he said. Dr. Gulani analyzes the scar based on the position of the scar and has simplified its nomenclature for teaching purposes into “on-cornea” or “in-cornea.” He has access to the world’s most sophisticated and futuristic diagnostic technologies but emphasizes that all technology pales compared with the superior refraction ability that the LASIK surgeon should possess.

“The most important thing I do with these patients is that I manually [perform refraction] through the scar,” Dr. Gulani said. “If the vision improves to better than 20/30, they undergo laser treatment. If the vision is less than 20/40, I do a hard contact lens trial; if the vision is better than 20/30 they undergo laser treatment and less than 20/40 they undergo a two-stage PRK procedure.”

He provided an example with a case in which the scar was on the cornea. The scar could be peeled and, with a refractive PRK procedure, achieve an excellent emmetropic outcome.

“On-corneal scars actually cause bizarre refractive errors including high astigmatism,” he said. “If surgeons keep ‘chasing’ it, they are actually chasing a camouflaged refraction and not the true refraction. Cases such as these do very well with peeling of the scar followed by laser ablation.”

In contrast, in-corneal scars become part of the cornea and become a refractive error and, therefore, should be treated as a refractive error, with no attention paid to the scar, Dr. Gulani said.

“Despite residual scars, the patients achieve 20/20 or better vision,” he said.

He emphasized that this algorithm can be applied in almost any scenario of anterior corneal scarring, including patients who have undergone previous refractive surgery or previous epikeratophakia, and anterior corneal dystrophies with refractive errors.

Of course, those with structural instability will require the 5S system first to build the cornea, followed by laser PRK as a planned stage.

And again, using Corneoplastique principles, a surgeon can combine this concept with any combination of intraocular surgery and lens implant sequels. Dr. Gulani provided an example of a multifocal lens implant “nightmare” case that was referred to him. The problem was corrected with two procedures staged for emmetropia, and the patient achieved 20/20 vision from 20/200 vision preoperatively.

“Using this concept, most corneal scars, including those resulting from LASIK or PRK complications, can be addressed using laser PRK to go through the scar for a refractive outcome, bringing patients back to excellent unaided emmetropia,” Dr. Gulani said.

Dr. Gulani has no financial interest in the subject matter.

References

1. Gulani AC. Principles of surgical treatment of irregular astigmatism in unstable corneas. Text book of irregular astigmatism. Diagnosis and treatment. Thorofare, NJ: SLACK Incorporated; 2007:251-261.

2. Gulani AC, Holladay J, Belin M, Ahmed I. Future technologies in LASIK-Pentacam advanced diagnostic for laser vision surgery. In: Experts Review of Ophthalmology. London, 2012. (in press)

3. Gulani AC. A new concept for refractive surgery: Corneoplastique. Ophthalmology Management. 2006;57-63.

4. Gulani AC. Corneoplastique: Art of vision surgery. Video Journal of Cataract and Refractive Surgery. 2006;22(3).

5. Gulani AC. Corneoplastique. Techniques in Ophthalmology. 2007;5:11-20.

6. Gulani AC. Laser vision surgery and corneal scars. Video Atlas of Ophthalmic Surgery. 2010; section vi; video ii.

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