Eyeworld

EW CORNEA 118 October 2017 by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer Corneal lifting uses a crescentic keratectomy approach to stop keratoconus progression and reduce astigmatism A new procedure called "corneal lifting" can pro- duce corneal flattening, a reduction in the anterior chamber depth, and a decreased incidence of optical aber- rations in patients with keratoconus, according to data presented at the 2017 ASCRS•ASOA Symposium & Congress in Los Angeles by Cesar Carriazo, MD, Clinica Carriazo, Barranquilla, Colombia. The successful management of keratoconus requires a combined strategy of stopping the progres- sion of ectasia along with visual rehabilitation. "We have experience now with a technique that uses the excimer or femtosecond laser to re- shape the ectatic cornea by means of crescentic keratectomy," Dr. Carriazo said. "The benefit of this technique is the reduction of anterior cham- ber depth, one of the hallmarks of keratoconus, and the correction of irregular astigmatism and higher order aberrations, despite using large optical zones." Corneal lifting Dr. Carriazo's surgical technique varies slightly, depending on which laser method is chosen. With the excimer laser, the surgery involves the use of a crescentic mask that was developed by Dr. Carriazo. The mask is transparent and is placed on the cornea. Laser is used to penetrate through the mask onto the cornea and remove the tissue. The mask is shaped differently, according to how much corneal tissue needs to be removed. The shape and size of the resection is altered depending on the grade of keratoconus. For femto- second laser procedures, Dr. Carriazo employs a software platform, as opposed to the mask. After anesthetic drops are applied, an 8 mm in diameter crescentic mask is placed on the New approach to managing keratoconus: Laser crescentic keratectomy 270-degree keratectomy by femtosecond laser ablation 270-degree ablation piece removed by femtosecond laser Interrupted stitches after ablation Three-month postoperative slit lamp examination Source: Cesar Carriazo, MD cornea. The mask is aligned with the patient's pupil. A platform devel- oped for this procedure is used to perform the ablation of either 180 degrees, 270 degrees, or 360 degrees of corneal tissue, through the mask. The larger the defect, the more tissue is ablated. Dr. Carriazo noted that smaller ablations of 120 degrees were insufficient to counter the strong force from the peripheral cor- nea postoperatively. Once ablation is completed, Dr. Carriazo performs a paracentesis to reduce the intra- ocular pressure and help suture the edges of the corneal resection with interrupted stitches. Prospective study Dr. Carriazo performed corneal lifting in 63 patients in a prospec- tive study at his institute. His results after 30 months of follow-up (range: 1–30 months) in 63 keratoconus pa- tients (15 female, 48 male; mean age 30.83 ± 12.65 years) who underwent corneal lifting revealed improved vi- sual acuity and a reduction in higher order aberrations postoperatively, especially coma. The anterior chamber was re- duced from 3.91 ± 1.48 mm preoper- atively to 3.52 ± 1.21 mm postopera- tively (P<.000005). "The decrease in anterior chamber depth was –0.38 ± 0.15 mm. This means the position of the epithelium was changed to the position of the endothelium because we reduced the anterior chamber by 400 µm," Dr. Carriazo explained. According to his outcomes, the mean endothelial cell count in the patient group was 2170 ± 363 preop- eratively and 2032 ± 329 postopera- tively (P>.05). The thinnest corneal point was 442.35 ± 85.13 µm. Pa- chymetry did not show any statisti- cally significant changes, measuring 442.35 ± 85.13 µm preoperatively and 455.49 ± 77.25 µm postopera- tively (P>.05). At 2 years, uncorrected visual acuity increased from 0.04 ± 0.06 to 0.21 ± 0.17 (P=.0001), and the best corrected visual acuity increased from 0.33 ± 0.15 to 0.72 ± 0.45 (P=.000001). The spherical equiv- alent was –5.47 ±2.59 D preopera- tively and –1.82 ± 0.45 D postoper- atively (P=.0000001). Higher order

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