Eyeworld

58 | EYEWORLD | SEPTEMBER 2023 C ORNEA References 1. Barraquer J. Modification of refraction by means of intracor- neal inclusions. Int Ophthalmol Clin. 1966;6:53–78. 2. Colin J, et al. Correcting keratoconus with intracorneal rings. J Cataract Refract Surg. 2000;26:1117–1122. 3. Dockery PW, et al. Intracorneal ring segment implantation in advanced keratoconus. Eur J Ophthalmol. 2023;33:1324–1330. 4. Jacob S, et al. Corneal allogen- ic intrastromal ring segments (CAIRS) combined with corneal cross-linking for keratoconus. J Refract Surg. 2018;34:296–303. 5. Haciagaoglu et al. Allograft corneal ring segment for kera- toconus management: Istanbul nomogram clinical results. Eur J Ophthalmol. 2022. Online ahead of print. 6. Nacaroglu SA, et al. Efficacy and safety of intracorneal allo- genic ring segment implantation in keratoconus: 1-year results. Eye (Lond). 2023. Online ahead of print. study included 24 patients with keratoconus, stage 1 to 4, with 6–18 months of follow-up. The procedure resulted in significant improve- ment in UDVA, CDVA, and other improvements. Since then, Dr. Jacob has enhanced the CAIRS procedure with customization. She said it can be implanted in small optic zones (4.2–4.3 mm), and arc length, thickness, and shape can be customized for individual patient needs. "This customization can be done to match exactly to the patient's topography, unlike the synthetic segments where fixed thickness or width gradations are present (i.e., there is a fixed gradient from one end to the other)," she said. "In CAIRS … the gradient can change extremely locally as per the patient's topogra- phy. This can be done using the Jacob CAIRS Customizer [Epsilon Instruments] and the man- ual Jacob CAIRS Trephine [Madhu Instruments] or using the femtosecond laser." Dr. Jacob said CAIRS can be implanted more superficially than synthetic segments, allowing a greater effect without the risk of corneal melts. Dr. Jacob said more than 600 patients with all grades of keratoconus have undergone CAIRS. "The patient experience has been very positive with patients reporting a decrease in distortion and improvement in visual acuity," she said. "The refractive error comes down and becomes more tolerable. Most have bilateral disease and undergo sequential bilateral sur- gery, again showing that they like the outcome from the surgery. In addition, many refer their friends from support groups or other known contacts who suffer from ectasia. CAIRS has also been accepted with enthusiasm by kerato- conus specialists around the world, indicating its safety and efficacy." Dr. Jacob said that compared to DALK, CAIRS is minimally invasive with less of a learn- ing curve. Compared to other allogenic tech- nologies, such as lenticule implantation, CAIRS leaves the visual axis untouched. Compared to subtractive techniques, such as topography- guided PRK, Dr. Jacob said there is no risk of destabilizing non-progressive keratoconus with CAIRS. "Being an additive technology, [CAIRS] has the advantage of being able to harness a much greater amount of effect. In subtractive tech- niques, the effect that can be obtained has to be balanced against the risk of inducing progres- sion of keratoconus because of the amount of tissue removed. Thus, large effects cannot be obtained," she said. Dr. Dockery thinks one of the biggest ad- vantages of allogenic segments over synthetic is continued from page 56 A) Jacob CAIRS Trephine; B) Jacob CAIRS Customizer Pre- and post-CAIRS: Top left shows preop sagittal curvature map, top right shows postop sagittal curvature map, bottom left shows difference map with a maximum flattening of 15.8 D achieved, bottom right shows the postop slit lamp image Source (all): Soosan Jacob, MD

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