Abstract
Purpose: :
The Intracor represents a new treatment option of surgery for presbyopia. It consists in five concentric intrastromal cuts with the femtosecond (Technolas Perfect Vision®) without cutting through the epithelium. Its mechanism of action remains unclear. The aim of this study is to describe the intrastromal incisions histology and ultrastructure on human corneas grafts and to compare if it is possible to perform the same shape with the Intralase (Abbott Medical Optics®) femtosecond laser.
Methods: :
Our study was conducted on 5 human corneas supplied by the French Eye Bank. Histological section through the center shows corneal intrastromal incisions numbered vertical center to the periphery by the numbers 1, 2, 3, 4 and 5 at each half-cornea, called A and B. The various measurements were made on half-thin sections after staining with toluidine blue and using for each cornea, the length of the 5 incisions, the distance between Bowman and the incision, the distance between the incision and Descemet's membrane and the total corneal thickness were measured. We calculated the average lengths of the different incisions. We also measured the distance between the incisions at 3 different levels of stromal depth.The same study was performed with the Intralase femtosecond laser using the IEK module (with only 4 concentric intrastromal cuts) with the parameters of the original intracor shape.The aim is to compare the concentric cuts to see if it is possible to perform the intracor cut with an other laser.
Results: :
Obtained from measurements, we calculated the average lengths (N) and standard deviations of the incisions (N1 = 299μm + / -45.72, N2 = 263μm + / -37.19, N3 = 224μm + / -32.74, N4 = 208μm + / -31.41 , N5 = 180μm + / -36.42) The diameter of the rings (A) was measured (A1 = 1690μm, 2080μm = A2, A3 = 2546μm, 2890μm = A4, A5 = 3287μm) The average spacing (E) between the incisions were measured (E1 = 187μm, 205μm = E2, E3 = 190μm, 189μm = E4, E5 = 188μm)
Conclusions: :
In this study, we tried to describe for the first time, the incisions intrastromal histology and ultrastructure on human corneas grafts of corneas bank using two different femtosecond laser. The results show some differences between the two methods, corneas linked to technical artefacts of the study. The histologic and ultrastructural study allowed us to highlight the specific architecture of intrastromal incisions on human corneas from bank Intracor laser technique. Other studies, especially in vivo, are needed to compare results and help them to consider the mode of action of this new technique We compare our measurements to those referenced by Technolas,and they are rigorously close.
Keywords: cornea: stroma and keratocytes • laser • presbyopia