Back to Freepaper Session
Assessment of the KAMRA inlay clinical results using videokeratography and corneal OCT: two year results
Session Title: Intracorneal inlays for correction of presbyopia
Session Date/Time: Tuesday 08/10/2013 | 08:00-10:30
Paper Time: 08:06
Venue: Main Lecture Hall (Ground Floor)
First Author: : F.Carones ITALY
Co Author(s): :
To correlate the videokeratographic and ocular coherence tomography (OCT) findings with the clinical results from eyes which underwent Kamra inlay implantation (Acufocus, Inc.) to correct presbyopia. Eyes were either emmetropic, myopic or hyperopic, with or without astigmatism. The target of the surgical procedure was to provide them with the best possible uncorrected visual acuity at all distances, thus correcting any preexisting visual error by excimer laser ablation at the same time of the inlay implant (combined LASIK and Kamra implant, CLK).
Carones Ophthalmology Center, outpatient private ambulatory clinic, Milan, Italy.
Forty eyes of 40 patients (age range 43 to 57 years) have been followed over a two-year period. The inlay was implanted under an attempted 200 µm, 9.0 diameter corneal flap using the WaveLight FS200 Femtosecond laser. Twenty-four eyes received simultaneous excimer laser ablation (WaveLight EX500) to correct hyperopia (+0.75 to +3.75 D) and 12 eyes were treated to correct myopia (-1.25 to -4.50 D) in the same way. Four eyes being plano just received the implant. Refraction, uncorrected (UCVA) and best corrected visual acuity (BCVA) were tested at 4 meters for distance, at 65 cm for intermediate, and at 45 cm for near. Accomodative amplitude was also measured. Corneal topography was assessed with the Keratron Onda (Optikon 2000), the Vario (Oculus), and with the Sirius Scheimpflug/placido topographer (CSO). Corneal OCT was performed with the OTI. Assessments were performed before and the day after surgery, at 1 week, then at 1, 3, 6 months after the procedure and then at 6-month intervals up to 2 years.
At the 3 month and all subsequent visits, none of the eyes had less than 20/25 BCVA at 4 meters distance, and none of the eyes lost more than one Snellen BCVA line compared to preoperatively. At the same distance, UCVA was 20/25 or better in 34 eyes (85%). Accommodation amplitude measured an average of 2.75±0.45 D with 36 eyes (90%) being able to read 20/25 or better at 45 cm. Corneal OCT measured flaps in the range 171 to 211 µm. Corneal topography showed a mild circular steeper area over the inlay which correlated with: a) the flap thickness (the thinner, the steeper, r=-0.723), b) time after surgery (steeper at 1 and 3 months, then decreasing), c) the type of attempted correction (steeper in eyes which had hyperopic ablation).
These findings indicate: 1) The Kamra inlay produces good results to correct presbyopia when implanted in conjunction with LASIK to correct preexisting refractive errors. BCVA is only minimally affected, and UCVA results are satisfactory at all distances. 2) The inlay produces better results when implanted deeper in the cornea. Visual stability is higher, recovery is faster, and corneal topography measures more regular anterior corneal curvature. 3) Corneal topography changes, like steepening over the area of the inlay, are good predictors for the evaluation of the corneal healing response in terms of tissue reaction over the inlay. 4) Corneal OCT can be helpful to assess the actual flap thickness and to evaluate the stromal over the inlay.