1
|
Ma RT, Hu DWJ, Zhou LH, Li WP, Li YJ, Yi BX. Botulinum toxin type A in treating early-stage patients with small-angle acute acquired comitant esotropia. Int J Ophthalmol 2024; 17:1094-1101. [PMID: 38895688 PMCID: PMC11144776 DOI: 10.18240/ijo.2024.06.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 03/12/2024] [Indexed: 06/21/2024] Open
Abstract
AIM To investigate botulinum toxin A (BTXA) efficacy on small-angle (≤25Δ) acute acquired concomitant esotropia (AACE) in early-stage patients. METHODS The electronic medical record data of AACE patients during March 2019 and June 2023 were collected in this retrospective and hospital-based cohort study. A total of 72 small-angle AACE patients received BTXA extraocular muscle injection. Patients were grouped by onset-to-treatment time (Group A: ≤6mo, Group B: >6mo). Deviation of esotropia, eye alignment and stereopsis were analyzed at the period of pre/post-injection (1wk, 1, 3, and 6mo). Orthophoria rate at 6mo (horizontal deviation <10Δ and binocular single vision) were considered as outcome index. RESULTS There were no significant baseline differences (P>0.05) between two groups except onset-to-treatment time (2mo vs 11mo, P<0.001). Higher orthophoria rates were in Group A at last follow-up (94.74% vs 73.53%, P=0.013). Post-BTXA deviations of two groups at 1mo showed no difference (P>0.05); while in 3 and 6mo Group A was significantly smaller than group B (all P<0.001). No statistically significant differences were observed among all post-BTXA deviations of near and distance in Group A. In Group B, deviation at 3mo (near: 2Δ vs 0, P<0.001; distance: 4Δ vs 0, P<0.001) and 6mo (near: 6Δ vs 0, P<0.001; distance: 6Δ vs 0, P<0.001) was significant increased compared to deviation at 1wk after treatment. Group A showed better stereopsis recovery in last follow-up compared to Group B (80″ vs 200″, P=0.002). Both groups obtained improved stereopsis after treatment (Group A: 80″ vs 300″, P<0.001; Group B: 200″ vs 300″, P=0.037). CONCLUSION BTXA is effective for AACE with small deviation (≤25Δ) in early stage. Delayed treatment (>6mo) may reduce BTXA efficacy. Early BTXA intervention benefits long-term eye alignment and stereopsis recovery.
Collapse
Affiliation(s)
- Run-Ting Ma
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Die-Wen-Jie Hu
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Lian-Hong Zhou
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Wen-Ping Li
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Yuan-Jin Li
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Bei-Xi Yi
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| |
Collapse
|
2
|
Xu J, Yang F, Lin P, Qian D, Zheng T. Biometric factors associated with the postoperative visual performance of a multifocal intraocular lens. Heliyon 2024; 10:e31867. [PMID: 38845945 PMCID: PMC11154599 DOI: 10.1016/j.heliyon.2024.e31867] [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] [Received: 02/06/2024] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 06/09/2024] Open
Abstract
Purpose To identify the biometric factors associated with postoperative visual performance after uneventful phacoemulsification with multifocal intraocular lens (MIOL) implantation. Methods In this retrospective cohort study, 72 eyes of 72 patients implanted with the HumanOptics Diff-aAY MIOL were included. Preoperative examination data including the white-to-white distance (WTW), anterior chamber depth (ACD), axial length and corneal astigmatism were gathered through the electronic medical records. One month postoperatively, the pupil parameters, corneal aberrations, corneal astigmatism, IOL tilts and IOL decentrations were measured using an OPD-Scan III aberrometer. Postoperative visual performance parameters were recorded as the visual acuity, depth of focus, modulation transfer function (MTF) and point spread function (PSF) values, area under log contrast sensitivity function (AULCSF), retinal straylight and visual function questionnaire scores. Univariate and multivariate linear regression analyses were then performed to evaluate the associations between the potential biometric factors and postoperative visual outcomes. Results Younger age predicted greater MTF and PSF values, better AULCSF and better retinal straylight (P < 0.05). A lower corneal trefoil predicted better MTF and PSF values (P < 0.05). Smaller IOL decentration predicted better distance-corrected near visual acuity, greater AULCSF and better retinal straylight (P < 0.05). A less negative spherical equivalent (SE) predicted better MTF values (P = 0.017), while a more negative SE predicted better Visual Function Index-14 (VF-14) questionnaire scores and satisfaction scores (P < 0.05). A higher IOL power predicted better best corrected distance visual acuity (P = 0.005). Lower preoperative corneal astigmatism predicted greater MTF values (P = 0.020). Lower postoperative corneal astigmatism, smaller corneal high-order aberrations (HOAs), smaller photopic pupil size, larger WTW and deeper ACD predicted a better AULCSF (P < 0.05). Conclusions IOL decentration, IOL power, age, preoperative and postoperative corneal astigmatism, SE, photopic pupil size, corneal trefoil, WTW, ACD and corneal HOAs were significantly associated with postoperative visual performance. These findings might aid in patient selection prior to MIOL implantation.
Collapse
Affiliation(s)
- Jie Xu
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia and Related Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Fan Yang
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia and Related Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Peimin Lin
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia and Related Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Dongjin Qian
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia and Related Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Tianyu Zheng
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia and Related Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| |
Collapse
|
3
|
Yigit DD, Kockar A, Gurez C, Inal A, Gokyigit B. A Comparative Analysis of Surgical Outcomes for Infantile Esotropia With and Without Prior Botulinum Toxin a Injection. J Pediatr Ophthalmol Strabismus 2024:1-7. [PMID: 38380936 DOI: 10.3928/01913913-20240102-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
PURPOSE To compare the surgical outcomes in patients who had a failed botulinum toxin A injection before surgery versus those who had surgery as primary treatment (primary surgery) for infantile esotropia. METHODS The files of patients who had strabismus surgery in the Strabismus Unit of Beyoglu Eye Training and Research Hospital between January 2012 and March 2022 were reviewed. This study included 104 eyes of 52 patients with infantile esotropia. The angle of deviation before and 1, 3, and 6 months after botulinum toxin A injection or surgery, complications, pattern deviations, family history, abnormal head position, history of prematurity, intensive care unit admission, and consanguineous marriage were noted. A successful outcome was defined as ocular alignment of 10 prism diopters (PD) or less. RESULTS The study population consisted of 52 patients: 27 (52%) boys and 25 (48%) girls. In the botulinum toxin A group (n = 26), the mean age at admission was 14.0 ± 6.8 months, whereas the mean preoperative near and far angle of deviation were 41.92 ± 12.2 and 41.3 ± 13.0 PD, respectively. The mean age at the time of surgery was 40.6 ± 18.1 months. In the primary surgery group (n = 26), the mean age at admission was 34.0 ± 15.9 months. The mean preoperative near and far angle of deviation were 37.3 ± 8.0 and 35.3 ± 10.5 PD, respec tively. The mean age at the time of surgery was 48.1 ± 18.5 months. The success rates 6 months after treatment in the botulinum toxin A group and the primary surgery group were 76.9% and 88.5% in near (P > .05) and 80.8% and 88.5% in far (P > .05), respectively. Three patients had transient ptosis and one had consecutive exotropia after botulinum toxin A injection. CONCLUSIONS In infantile esotropia treatment, strabismus surgery after failed botulinum toxin A injection compared to primary surgery has statistically comparable surgical success rates. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XXX-XXX.].
Collapse
|
4
|
Oyemade KA, Xu TT, Lopez Dominguez J, Dumbrava MG, Hodge DO, White LJ, Dalvin LA. Population-based incidence of intraocular tumours in Olmsted County, Minnesota. Br J Ophthalmol 2023; 107:1369-1376. [PMID: 35450938 PMCID: PMC10350913 DOI: 10.1136/bjophthalmol-2021-320682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 04/12/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS To determine population-based incidence of intraocular tumours in Olmsted County, Minnesota. METHODS Record review of the Rochester Epidemiology Project medical record linkage system from 1 January 2006 to 31 December 2015 for patient demographics, tumour type by clinical diagnosis and presence or absence of confirmation by histopathology. The incidence rate of any intraocular tumour and of each tumour type was calculated per million person-years. Poisson regression analysis was used to analyse changes in incidence over time. RESULTS There were 948 patients diagnosed with intraocular tumours resulting in an age-adjusted and sex-adjusted incidence rate of 727.5 per million (95% CI: 680.8 to 774.2, p<0.05). Most tumours were benign (953, 98%). Of the benign lesions, melanocytic lesions were the majority (942, 97%), with adjusted incidence rates of 646.9 (95% CI: 602.8 to 691.1) for choroidal nevus and 55.8 (95% CI: 43.2 to 64.8) for iris nevus. Malignant lesions were rare (16, 2%) with 13 cases of choroidal melanoma and 1 case each of iris melanoma, retinal leukaemic infiltration and metastasis. The adjusted incidence rate for choroidal melanoma was 7.1 (95% CI: 2.5 to 11.8). CONCLUSION In a population-based setting, most intraocular tumours are benign and melanocytic. Although malignant lesions are less common, it is important to remain vigilant with appropriate monitoring given the potential for vision loss and life-threatening malignancy.
Collapse
Affiliation(s)
| | - Timothy T Xu
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA
| | | | | | - David O Hodge
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, Florida, USA
| | - Launia J White
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, Florida, USA
| | - Lauren A Dalvin
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA
| |
Collapse
|
5
|
Li Y, Tong L, Chen Y, Zhang B, Wan M, Yin X, Zhang F. The efficacy of botulinum toxin type A treatment and surgery for acute acquired comitant esotropia. Front Med (Lausanne) 2023; 10:1219419. [PMID: 37601790 PMCID: PMC10436330 DOI: 10.3389/fmed.2023.1219419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/18/2023] [Indexed: 08/22/2023] Open
Abstract
Aim To compare the long-term efficiency of botulinum toxin type A (BTXA) injection and surgery on acute acquired comitant esotropia (AACE). Methods This retrospective study enrolled patients with AACE from January 2020 to August 2022. The horizontal angle of deviation pre- and post-treatment was measured. Deviations in BTXA and surgical treatment were compared. The BTXA group was divided into adequate treatment (AT) and inadequate treatment (inAT) subgroup based on the deviation of no more than 4 prism diopters (at near and distance) or temporary exotropia at the 2 week follow-up. The two subgroups were compared to determine the long-term efficacy of BTXA treatment. Results Ninety-two patients with AACE were included. Follow-up was 6 months. The deviations of the surgery and BTXA group were significantly smaller at the 6 month follow-up than at pre-treatment (p < 0.001). The deviation before treatment in the surgery group was larger than in the BTXA groups (p < 0.001) but smaller at the 6 month follow-up (p < 0.001). The deviation was similar in the AT-BTXA and inAT-BTXA subgroups before treatment (p = 0.322 for distance and p = 0.051 for near) but smaller in the AT-BTXA subgroup at 6 month follow-up (p < 0.001 for near and distance). Conclusion Surgery and BTXA successfully treat AACE. Surgery has a more precise and lasting therapeutic effect than BTXA. AACE patients adequately treated with BTXA and with deviations of no more than 4 prism diopters at 2 weeks follow-up had better outcomes.
Collapse
Affiliation(s)
- Yipao Li
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Luyao Tong
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
- The First Affiliated Hospital of Ningbo University, Ningbo, China
| | - Yuanyuan Chen
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - BinJun Zhang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Minghui Wan
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xiangping Yin
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Fang Zhang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| |
Collapse
|
6
|
Rocha-de-Lossada C, Rodríguez-Vallejo M, Rodríguez-Calvo-de-Mora M, Ribeiro FJ, Fernández J. Managing low corneal astigmatism in patients with presbyopia correcting intraocular lenses: a narrative review. BMC Ophthalmol 2023; 23:254. [PMID: 37280550 DOI: 10.1186/s12886-023-03003-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 05/31/2023] [Indexed: 06/08/2023] Open
Abstract
Cataract surgery has become a refractive procedure in which emmetropia is the goal, with the implantation of extended depth-of-focus or multifocal intraocular lenses (IOLs) being the commonly selected option to restore vision beyond the far distance. The selection criteria for implanting these lenses can differ from those for monofocal IOLs and even between technologies, as eye characteristics can affect postoperative visual performance. Corneal astigmatism is an eye characteristic that can affect visual performance differently, depending on the implanted IOL. The magnitude of corneal astigmatism, the tolerance of the IOL to this astigmatism, economic aspects, comorbidities, and the efficacy of astigmatism treatment are factors that can make surgeons' doubt as to what astigmatism treatment should be applied to each patient. This review aims to summarize the current evidence related to low astigmatism tolerance in presbyopia-correcting lenses, the efficacy achieved through corneal incisions, and their comparison with the implantation of toric IOLs.
Collapse
Affiliation(s)
- Carlos Rocha-de-Lossada
- Qvision, Department of Ophthalmology of VITHAS Almería Hospital, Almería, 04120, Spain
- Ophthalmology Department, VITHAS Málaga, Málaga, 29016, Spain
- Hospital Regional Universitario de Málaga, Plaza del Hospital Civil, S/N, Málaga, 29009, Spain
- Departamento de Cirugía, Universidad de Sevilla, Área de Oftalmología. Doctor Fedriani, S/N, Sevilla, 41009, Spain
| | | | - Marina Rodríguez-Calvo-de-Mora
- Qvision, Department of Ophthalmology of VITHAS Almería Hospital, Almería, 04120, Spain
- Ophthalmology Department, VITHAS Málaga, Málaga, 29016, Spain
- Hospital Regional Universitario de Málaga, Plaza del Hospital Civil, S/N, Málaga, 29009, Spain
| | - Filomena J Ribeiro
- Departamento de Oftalmologia, Hospital da Luz, Lisbon, 1500-650, Portugal
- Faculdade de Medicina, Universidade de Lisboa, Lisbon, 1649-028, Portugal
| | - Joaquín Fernández
- Qvision, Department of Ophthalmology of VITHAS Almería Hospital, Almería, 04120, Spain
| |
Collapse
|
7
|
Pereira A, Aldrees S, Pimentel MC, Yan P. Updated review: optical coherence tomography findings of the pachychoroid disease spectrum. CANADIAN JOURNAL OF OPHTHALMOLOGY 2023; 58:e33-e35. [PMID: 35868437 DOI: 10.1016/j.jcjo.2022.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 04/21/2022] [Accepted: 06/23/2022] [Indexed: 10/17/2022]
Affiliation(s)
| | | | | | - Peng Yan
- University of Toronto, Toronto, ON; Kensington Eye Institute, Toronto, ON.
| |
Collapse
|
8
|
Suwannaraj S, Rojanasaksothron C, Methapisittikul Y, Wongwai P, Yospaiboon Y. Botulinum Toxin Injection versus Extraocular Muscle Surgery for Acute Acquired Comitant Esotropia. Clin Ophthalmol 2023; 17:413-420. [PMID: 36748049 PMCID: PMC9899017 DOI: 10.2147/opth.s401019] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 01/26/2023] [Indexed: 02/01/2023] Open
Abstract
Purpose To compare the success rate of extraocular muscle surgery and botulinum toxin injection for treatment in patients with acute acquired comitant esotropia (AACE). Patients and Methods This is a retrospective cohort study in which we treated 34 patients of AACE with botulinum toxin compared with 80 patients who had been treated with surgery. The data included angle of deviation in prism diopter (PD) at baseline and one, three, and six months after treatment. The main outcome was the success rate in each treatment group. Results In the surgery group, mean esodeviation angles at baseline and one, three, and six months after treatment were 50.8 ± 18.3 PD, 4.9 ± 8.3 PD, 4.6 ± 9.5 PD, and 5.5 ± 10.3 PD, whereas those in the botulinum toxin group were 51.2 ± 14.3 PD, 13.9 ± 17.4 PD, 22.0 ± 19.3, and 31.3 ± 23.8 PD, respectively. There was a statistically significant difference in the deviation angles between the two groups (p < 0.001). The success rate in the surgery group at one, three, and six months was 81%, 84%, and 79%, whereas that in the botulinum toxin group was 50%, 27%, and 27%. Conclusion Botulinum toxin injection was not as effective as conventional extraocular muscle surgery in AACE patients. However, the treatment is safe, fast-acting, and improves both cosmetic appearance and quality of life. This may be considered as a chance for patients not preferring surgery.
Collapse
Affiliation(s)
- Sirinya Suwannaraj
- KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Chawisa Rojanasaksothron
- KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Yanasiri Methapisittikul
- KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Phanthipha Wongwai
- KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Yosanan Yospaiboon
- KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand,Correspondence: Yosanan Yospaiboon, KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, 123 Mitraparb Highway, Khon Kaen, 40002, Thailand, Tel +66-4336-3010, Fax +66-4334-8383, Email
| |
Collapse
|
9
|
Khoramnia R, Wallek H, Güngör H, Yildirim TM, Auffarth GU, Mayer CS. [Fixation of an intraocular lens using reverse optic capture with haptic tuck for intraoperative posterior capsule rupture]. Ophthalmologe 2021; 118:960-964. [PMID: 34143281 DOI: 10.1007/s00347-021-01432-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/03/2021] [Accepted: 05/18/2021] [Indexed: 10/21/2022]
Abstract
Exact positioning and optimal axial alignment are mandatory to achieve satisfactory postoperative refractive results after implantation of a toric or presbyopia correcting intraocular lens (IOL). Posterior capsule rupture can preclude stable capsular fixation. In such cases, reverse optic capture with haptic tuck results in stable fixation of the lens with respect to centering, rotation and axial position. Only the haptics are positioned in the capsule, behind the anterior capsulorrhexis. The optic remains in the sulcus; thus, the lens is fixed in the rhexis, providing long-term stability despite the presence of posterior capsule rupture.
Collapse
Affiliation(s)
- Ramin Khoramnia
- Universitäts-Augenklinik Heidelberg, International Vision Correction Research Centre (IVCRC), Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.
| | - Hannah Wallek
- Universitäts-Augenklinik Heidelberg, International Vision Correction Research Centre (IVCRC), Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland
| | - Helin Güngör
- Universitäts-Augenklinik Heidelberg, International Vision Correction Research Centre (IVCRC), Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland
| | - Timur M Yildirim
- Universitäts-Augenklinik Heidelberg, International Vision Correction Research Centre (IVCRC), Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland
| | - Gerd U Auffarth
- Universitäts-Augenklinik Heidelberg, International Vision Correction Research Centre (IVCRC), Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland
| | - Christian S Mayer
- Universitäts-Augenklinik Heidelberg, International Vision Correction Research Centre (IVCRC), Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland
| |
Collapse
|
10
|
Dependence of the heating effect on tissue absorption coefficient during corneal reshaping using different UV lasers: A numerical study. Phys Eng Sci Med 2021; 44:221-227. [PMID: 33475960 DOI: 10.1007/s13246-021-00971-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 01/05/2021] [Indexed: 10/22/2022]
Abstract
Corneal reshaping using laser ablation effect is a well-known ophthalmologic operation implemented to correct many vision disorders. UV pulsed lasers are utilized in this surgery due to their high absorption in corneal tissue without affecting the other parts of the eye. Ideally ablation may not be associated with heat transport, since high temperature is the enemy of soft tissues. However, the thermal effect of this procedure can cause tissue damage if the temperature rises above the safety level without appropriate handling. In the present study, we try to find the trade-off between efficient ablation and minimal temperature rise. So the thermal effect on the corneal tissue after applying five UV wavelengths; 193, 210, 213, 223 and 248 nm has been simulated and investigated by solving Penne's bio-heat transfer equation using the finite element method. A 3D model of the human cornea is constructed using COMSOL Multiphysics computer software and the temperature rise is determined at the end of the laser pulse. The same spot size and pulse duration are used for each wavelength. While the absorption coefficient of the corneal tissue is the only variable as it is a wavelength dependent. The proposed results show that, the heating effect is directly proportional to the absorption coefficient. The highest recorded temperature was 259 °C at 193 nm, while, the minimum value was (70.1 °C) recorded at 248 nm at which the cornea has the lowest absorption coefficient.
Collapse
|