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Cañones-Zafra R, Gros-Otero J, Garcia-Gonzalez M, Casado S, Ketabi S, Villa-Collar C, Teus MA. Atomic force microscopy for the evaluation of corneal surface roughness after femtosecond laser flap creation and excimer ablation. Int Ophthalmol 2023; 43:4131-4136. [PMID: 37505289 DOI: 10.1007/s10792-023-02821-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 07/10/2023] [Indexed: 07/29/2023]
Abstract
INTRODUCTION It is well known that the femtosecond laser lamellar cut induces some degree of surface roughness. Nevertheless, as in femtosecond laser-assisted LASIK (FS-LASIK), an excimer LASIK ablation is performed, and the post-ablation stromal bed should show some degree of smoothening. We decided to compare, using atomic force microscopy (AFM), the roughness of the corneal stromal bed, after a femtosecond lasers device flap was created with or without an excimer myopic ablation. METHODS Using 6 freshly enucleated porcine eyes, we created in every eye a flap using a femtosecond laser. Additionally, in 3 eyes, an excimer laser ablation to correct-3 diopters (D) was made. AFM imaging of the remaining corneal stroma was performed. Ten different square areas of 20 μm x 20 μm at the central area of the stroma of each corneal sample were studied. The roughness parameters used were the root-mean-square deviation from a perfectly flat surface. RESULTS The RMS deviation was 360 ± 120 nm in femtosecond laser only, and 110 ± 20 nm in those cases where excimer is also involved (p < 0.0001). CONCLUSIONS Our results show that the roughness of the surface treated with excimer is clearly lower than in the group with no excimer ablation; thus, the application of laser excimer after a flap created by femtosecond laser seems to soften the nano-irregularities created by this technique.
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Affiliation(s)
- Rafael Cañones-Zafra
- Department of Ophthalmology, Hospital Universitario Príncipe de Asturias, Carretera Alcalá-Meco S/N, 28805, Alcalá de Henares, Madrid, Spain.
- Clínica Novovisión, Madrid, Spain.
| | | | | | | | - Samira Ketabi
- Department of Ophthalmology, Hospital Universitario Príncipe de Asturias, Carretera Alcalá-Meco S/N, 28805, Alcalá de Henares, Madrid, Spain
| | - César Villa-Collar
- Clínica Novovisión, Madrid, Spain
- Department of Pharmacy, Biotechnology, Nutrition, Optics and Optometry, Universidad Europea de, Madrid, Spain
| | - Miguel A Teus
- Department of Ophthalmology, Hospital Universitario Príncipe de Asturias, Carretera Alcalá-Meco S/N, 28805, Alcalá de Henares, Madrid, Spain
- Clínica Novovisión, Madrid, Spain
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Titiyal JS, Aravind MJ, Kaur M, Nag TC, Sharma N, Agarwal T, Sinha R. Surface quality and endothelial cell viability after femtosecond laser-assisted donor lenticule preparation for endothelial keratoplasty - An in-vitro study. Indian J Ophthalmol 2020; 68:2404-2407. [PMID: 33120628 PMCID: PMC7774225 DOI: 10.4103/ijo.ijo_99_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Purpose To compare surface quality and endothelial cell viability of descemet stripping automated endothelial keratoplasty (DSAEK) donor lenticules prepared with femtosecond laser (FSL) or microkeratome (MK). Methods Experimental ex-vivo evaluation of 15 DSAEK donor lenticules prepared from optical quality donor corneas using 200 KHz FSL (9 eyes) or MK (6 eyes). Surface quality and smoothness of the cut were assessed using atomic force microscopy and endothelial cell viability was assessed using transmission electron microscopy. Results Mean lenticule thickness was 121.89 ± 17.13 μm in FSL group and 112.67 ± 5.89 μm in MK group (P = 0.33). Average roughness of stromal surface (RMSavg) [FSL- 30.51 ± 4.55 nm, MK-22.37 ± 1.83 nm; P = 0.02] and root mean square roughness (RMSrough) [FSL-31.39 ± 5.75 nm, MK-23.08 ± 0.40 nm; P = 0.012] was significantly more in FSL group. Increased granular and linear irregularities were observed in the FSL group. Endothelial cell disruption was more in FSL group (FSL- 29.49 ± 6.91% MK-13.28 ± 3.62%; P < 0.001) with decreased mean nucleus length (FSL-5.56 ± 0.17 μm, MK-7.52 ± 0.65 μm; P < 0.001). Conclusion Automated MKs are still the standard of care for donor lenticule preparation and MK-assisted donor lenticules have smoother surface with less endothelial cell disruption than FSL. Further research is mandatory before FSL platforms can be considered a viable alternative to the MK.
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Affiliation(s)
- Jeewan S Titiyal
- Cornea, Cataract and Refractive Surgery Services, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - M J Aravind
- Cornea, Cataract and Refractive Surgery Services, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Manpreet Kaur
- Cornea, Cataract and Refractive Surgery Services, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Tapas C Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
| | - Namrata Sharma
- Cornea, Cataract and Refractive Surgery Services, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Tushar Agarwal
- Cornea, Cataract and Refractive Surgery Services, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Rajesh Sinha
- Cornea, Cataract and Refractive Surgery Services, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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Ziebarth NM, Dias J, Hürmeriç V, Shousha MA, Yau CB, Moy VT, Culbertson WW, Yoo SH. Quality of corneal lamellar cuts quantified using atomic force microscopy. J Cataract Refract Surg 2012; 39:110-117. [PMID: 23141078 DOI: 10.1016/j.jcrs.2012.07.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 07/17/2012] [Accepted: 07/19/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE To quantify the cut quality of lamellar dissections made with the femtosecond laser using atomic force microscopy (AFM). SETTING Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA. DESIGN Experimental study. METHODS Experiments were performed on 3 pairs of human cadaver eyes. The cornea was thinned to physiologic levels by placing the globe, cornea side down, in 25% dextran for 24 hours. The eyes were reinflated to normal pressures by injecting a balanced salt solution into the vitreous cavity. The eyes were placed in a holder, the epithelium was removed, and the eyes were cut with a Visumax femtosecond laser. The energy level was 180 nJ for the right eye and 340 nJ for the left eye of each pair. The cut depths were 200 μm, 300 μm, and 400 μm, with the cut depth maintained for both eyes of each pair. A 12.0 mm trephination was then performed. The anterior portion of the lamellar surface was placed in a balanced salt solution and imaged with AFM. As a control, the posterior surface was placed in 2% formalin and imaged with environmental scanning electron microscopy (SEM). Four quantitative parameters (root-mean-square deviation, average deviation, skewness, kurtosis) were calculated from the AFM images. RESULTS From AFM, the 300 μm low-energy cuts were the smoothest. Similar results were seen qualitatively in the environmental SEM images. CONCLUSION Atomic force microscopy provided quantitative information on the quality of lamellar dissections made using a femtosecond laser, which is useful in optimizing patient outcomes in refractive and lamellar keratoplasty surgeries.
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Affiliation(s)
- Noël M Ziebarth
- From the Biomedical Atomic Force Microscopy Laboratory (Ziebarth, Dias), Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, and the Bascom Palmer Eye Institute (Hürmeriç, Shousha, Culbertson, Yoo) and the Department of Physiology and Biophysics (Yau, Moy), University of Miami Miller School of Medicine, Miami, Florida, USA.
| | - Janice Dias
- From the Biomedical Atomic Force Microscopy Laboratory (Ziebarth, Dias), Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, and the Bascom Palmer Eye Institute (Hürmeriç, Shousha, Culbertson, Yoo) and the Department of Physiology and Biophysics (Yau, Moy), University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Volkan Hürmeriç
- From the Biomedical Atomic Force Microscopy Laboratory (Ziebarth, Dias), Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, and the Bascom Palmer Eye Institute (Hürmeriç, Shousha, Culbertson, Yoo) and the Department of Physiology and Biophysics (Yau, Moy), University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Mohamed Abou Shousha
- From the Biomedical Atomic Force Microscopy Laboratory (Ziebarth, Dias), Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, and the Bascom Palmer Eye Institute (Hürmeriç, Shousha, Culbertson, Yoo) and the Department of Physiology and Biophysics (Yau, Moy), University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Chiyat Ben Yau
- From the Biomedical Atomic Force Microscopy Laboratory (Ziebarth, Dias), Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, and the Bascom Palmer Eye Institute (Hürmeriç, Shousha, Culbertson, Yoo) and the Department of Physiology and Biophysics (Yau, Moy), University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Vincent T Moy
- From the Biomedical Atomic Force Microscopy Laboratory (Ziebarth, Dias), Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, and the Bascom Palmer Eye Institute (Hürmeriç, Shousha, Culbertson, Yoo) and the Department of Physiology and Biophysics (Yau, Moy), University of Miami Miller School of Medicine, Miami, Florida, USA
| | - William W Culbertson
- From the Biomedical Atomic Force Microscopy Laboratory (Ziebarth, Dias), Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, and the Bascom Palmer Eye Institute (Hürmeriç, Shousha, Culbertson, Yoo) and the Department of Physiology and Biophysics (Yau, Moy), University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Sonia H Yoo
- From the Biomedical Atomic Force Microscopy Laboratory (Ziebarth, Dias), Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, and the Bascom Palmer Eye Institute (Hürmeriç, Shousha, Culbertson, Yoo) and the Department of Physiology and Biophysics (Yau, Moy), University of Miami Miller School of Medicine, Miami, Florida, USA
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