Eyeworld

EW CORNEA 38 January 2019 by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer created using a femtosecond laser that allowed ICRS implantation in the 6–7 mm optic zone. The ring segments were implanted deep in the corneal stroma, at 80% depth from the thinnest part of the cornea as measured by the anterior segment OCT. At 3 months following surgery, the Intacs SK group showed an increase in uncorrected distance visual acuity of logMAR 0.99 ± 0.35 at baseline to logMAR 0.29 ± 0.17, while the Keraring S16 group showed an increase in uncorrect- ed visual acuity of log MAR 0.93 ± 0.4 at baseline to logMAR 0.41 ± 0.34. The keratometric values were reduced in both groups, which seems to indicate that ectasia was thwarted. "Frequent postoperative controls are important to identify ectatic progression," Dr. Seitz said. "Progression is defined as a func- tion of the topographic refraction in the flat and steep axes. There is no progression if we observe no ICRS improve visual acuity in higher grade ectasia patients and help to stabilize the cornea I ntracorneal ring segments (ICRS) are emerging as a practi- cable treatment option in eyes with corneal ectatic disease. ICRS implantation is mini- mally invasive and complication free in the hands of an experienced surgeon. They can be explanted (reversible) and can be combined with or followed by corneal stabiliz- ing procedures, such as crosslinking (CXL). Approaches to the treatment of ectasia are stage related and include contact lenses, ICRS, CXL, deep anterior lamellar keratoplasty (DALK), and penetrating keratoplas- ty (PKP). Corneal ectatic disorders are a group of presumably non-inflam- matory, progressive eye conditions characterized by bilateral, often asymmetric corneal thinning. They are associated with a reduction in the mechanical strength of the cor- nea, a progressive decrease in visual acuity, and the development of both irregular astigmatism and corneal opacification. Ectatic disorders are either primary, as seen in keratoco- nus and pellucid marginal degen- eration, or iatrogenic, as noted in post-LASIK corneal ectasia. Intacs for ectatic disease Berthold Seitz, MD, Saarland Uni- versity Medical Center, Department of Ophthalmology, Homburg, Ger- many, shared his experience using ICRS in patients with keratectasia in a presentation he gave at the 2018 World Ophthalmology Congress. According to Dr. Seitz, ICRS were effective in stopping the progression associated with keratectasia and improved visual acuity. 1 His study included 84 eyes of 69 patients who received ICRS from August 2011 to September 2015, of which 74 eyes were implanted with Intacs SK (Addition Technology, Lombard, Illinois) and 10 eyes with the Keraring S16 (Mediphacos, Belo Horizonte, Brazil). The Intacs group was comprised of patients diagnosed with keratoconus who had con- tact lens intolerance (n=65 eyes), PMD (n=2 eyes), and post-LASIK keratectasia (n=6 eyes) with clear, unscarred central corneas, and one case involving a Ferrara Ring (AJL Ophthalmic, Araba, Spain) explanta- tion. The Keraring group was made up of 10 keratoconus eyes. The same surgeon conducted all of the surgeries and the tunnel was increase in K value of 1 D after two checkup exams within 6 months or any changes in visual acuity." When and how do ICRS work? In a study that evaluated the out- comes of ICRS for the treatment of keratoconus, corrected distance visual acuity (CDVA) decreased significantly in patients with mild keratoconus (P<0.01) but signifi- cantly increased in all other grades (P<0.05). The improvement in visual acuity and the decrease of kerato- metric and aberrometric values were stable over a long period of time in eyes with stable keratoconus. Eyes with progressive keratoconus showed a significant improvement immediately after the procedure, then had a significant regression of greater than 3 D by the end of the follow-up period. 2 The best indications for the implantation of ICRS were a loss of two or more lines of best corrected visual acuity after ectasia and eyes with post-LASIK ectasia grade 4, according to a study that evaluated the clinical results of ICRS in a large series of post-LASIK ectasia patients and determined which clinical pa- rameters were related to the success of the technique. Patients who lost two or more lines due to ectasia had a mean gain of 2.89 lines of corrected distance visual acuity after ICRS implantation (P<.001). In contrast, patients who did not lose vision after ectasia had a mean loss of –2.00 lines of CDVA after ICRS implantation (P<.001). The study showed that the odds ratio of a gain of at least one line of CDVA was 18 Intracorneal ring segments and ectasia Intacs SK for treatment of keratoconus, pellucid marginal degeneration, and iatrogenic keratectasia after LASIK Presentation spotlight According to [Dr. Seitz's] study outcomes, eyes with post-LASIK keratectasia benefited from Intacs implantation, improving corrected and uncorrected visual acuity. Intacs are placed in a midperipheral stromal tunnel created with the femtosecond laser in 80% depth, as measured with the anterior segment OCT in the 6–7 mm zone Source: Berthold Seitz, MD

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