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Lin Q, Shen Z. Effect of white-to-white corneal diameter on biomechanical indices assessed by Pentacam Scheimpflug corneal tomography and corneal visualization Scheimpflug technology. Int Ophthalmol 2022; 42:1537-1543. [PMID: 34988748 DOI: 10.1007/s10792-021-02144-x] [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: 09/27/2021] [Accepted: 11/19/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE To provide evidence for more accurate evaluation of refractive surgery candidates in clinics, this retrospective study investigated the effect of corneal diameter on the biomechanical indices assessed by Pentacam Scheimpflug cornea tomography (Pentacam) and corneal visualization Scheimpflug technology (Corvis ST). METHODS The relevant data were collected of 132 eyes from 132 participants with moderate myopia who were candidates for refractive surgery. Eligible participants were apportioned to 2 groups based on the white-to-white (WTW) corneal diameter: Group A, ≤ 11.5 mm, and Group B, ≥ 11.6 mm. A single clinician performed Pentacam and Corvis ST imaging on each subject for 3 consecutive measurements, and the means were used for statistical analyses. RESULTS Each group comprised 66 eyes. As measured by Pentacam, the 2 groups were comparable regarding Df and Da. For other measurements, Group A had significantly higher K1, K2, Db, Dp, Dt, Do, PPImin, PPImax, PPIavg, while Group B had significantly higher CCT, BFSf, BFSb, and ARTmax. Corvis ST data included DA ratio, SPA1, CBI, TBI, and ARTh. Only the latter showed a significant difference, with ARTh of group A (437.04 ± 76.60) larger than group B (470.46 ± 103.36, p = 0.04). CONCLUSION In a Chinese population, WTW corneal diameter showed effect on biomechanical indices assessed by Pentacam and Corvis ST. Personalized evaluation of these measurements based on corneal diameter should improve the sensitivity and specificity for screening of keratoconus by these devices.
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Affiliation(s)
- Qinghong Lin
- Department of Refractive Surgery, Hefei Bright Eye Hospital, No. 299 Feixi Road, Hefei, 230000, China
| | - Zhengwei Shen
- Department of Refractive Surgery, Hefei Bright Eye Hospital, No. 299 Feixi Road, Hefei, 230000, China.
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Tangmonkongvoragul C, Supalaset S, Tananuvat N, Ausayakhun S. Two-Step Transepithelial Photorefractive Keratectomy with WaveLight EX500 Platform for Adolescents and Adults with Low to Moderate Myopia: A 12-Month Comparative Evaluation. Clin Ophthalmol 2021; 15:4109-4119. [PMID: 34675478 PMCID: PMC8520963 DOI: 10.2147/opth.s336727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/01/2021] [Indexed: 11/29/2022] Open
Abstract
Purpose To compare the visual and refractive results obtained after two-step TransPRK using an EX500 excimer laser for low to moderate myopic correction in adolescents and adults. Patients and Methods Retrospectively, 91 eyes of 52 patients were categorized into four groups based on age and level of myopia. The demographics, data of efficacy, safety, predictability, stability, and post-operative complications were evaluated at 1, 3, 6, and 12 months post-operatively. Results At 1-month, adolescents with low myopia achieved the highest mean efficacy index (P =0.034). The efficacy indices continuously increased during the 1-year follow-up in all groups, except in adolescents with moderate myopia. The highest safety and efficacy indices were recorded in adolescents with low myopia at 1-year. Post-operative spherical equivalent within ±0.50 D at 1 year was 48.75% of all treated eyes; however, the final mean refractive spherical equivalent (MRSE) was under-corrected in all groups. By month 3, the percentage of eyes that had grade 0.5 haze was most prevalent in adolescents with moderate myopia (P <0.001). Conclusion two-step TransPRK using an EX500 proved to be an effective, predictable, stable and safe procedure for the correction of low to moderate myopia with or without astigmatism at 1 year. Adolescents with low myopia achieved the best-post-operative UDVA, efficacy and safety indices. Adolescents tolerated night visual problems and dry eye symptoms better than adults.
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Affiliation(s)
- Chulaluck Tangmonkongvoragul
- Department of Ophthalmology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,CMU LASIK Center, Center of Medical Excellence, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Sumet Supalaset
- Department of Ophthalmology, Chulabhorn Hospital, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Napaporn Tananuvat
- Department of Ophthalmology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,CMU LASIK Center, Center of Medical Excellence, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Somsanguan Ausayakhun
- Department of Ophthalmology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,CMU LASIK Center, Center of Medical Excellence, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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Liu Y, Zhang Y, Chen Y. Application of a scheimpflug-based biomechanical analyser and tomography in the early detection of subclinical keratoconus in chinese patients. BMC Ophthalmol 2021; 21:339. [PMID: 34544392 PMCID: PMC8454178 DOI: 10.1186/s12886-021-02102-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 09/07/2021] [Indexed: 11/10/2022] Open
Abstract
Background In vivo corneal biomechanics evaluation has been used to help screen early keratoconus in recent years. This study is to evaluate the value of a Scheimpflug-based biomechanical analyser combined with tomography in detecting subclinical keratoconus by distinguishing normal eyes from frank keratoconus (KC) and forme frusta keratoconus (FFKC) eyes in Chinese patients. Methods Study design: diagnostic test. This study included 31 bilateral frank keratoconus patients, 27 unilateral clinically manifesting keratoconus patients with very asymmetric eyes, and 79 control subjects with normal corneas. Corneal morphological and biomechanical parameters were measured using a Pentacam HR and a Corvis ST (OCULUS, Wetzlar, Germany). The diagnostic ability of computed parameters reflecting corneal biomechanical and morphological traits [including the Belin-Ambrósio deviation index (BAD_D), the Corvis biomechanical index (CBI) and the tomographic and biomechanical index (TBI)] was determined using receiver operating characteristic (ROC) curve analysis and compared by the DeLong test. Additionally, the area under the curve (AUC), the best cut-off values, and the Youden index for each parameter were reported. A novel corneal stiffness parameter, the stress-strain index (SSI), was also compared between KC, FFKC and normal eyes. Results Every morphological and biomechanical index analysed in this study was significantly different among KC, FFKC and normal eyes (P = 0.000). The TBI was most valuable in detecting subclinical keratoconus (FFKC eyes), with an AUC of 0.928 (P = 0.000), and both forms of corneal ectasia (FFKC and frank KC eyes), with an AUC of 0.966 (P = 0.000). The sensitivity and specificity of the TBI was 97.5 and 77.8 % in detecting FFKC and 97.5 and 89.7 % in detecting any KC, respectively, with a cut-off value of 0.375. The morphological index BAD_D and the biomechanical index CBI were also very useful in distinguishing eyes with any KC from normal eyes, with AUCs of 0.965 and 0.934, respectively. The SSI was significantly different between KC, FFKC and normal eyes (P = 0.000), indicating an independent decrease in corneal stiffness in KC eyes. Conclusions The combination of a Scheimpflug-based biomechanical analyser and tomography could increase the accuracy in detecting subclinical keratoconus in Chinese patients. The TBI was the most valuable index for detecting subclinical keratoconus, with a high sensitivity and specificity. Evaluation of corneal biomechanical properties in refractive surgery candidates could be helpful for recognizing potential keratoconic eyes and increasing surgical safety.
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Affiliation(s)
- Yan Liu
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Restoration of Damaged Ocular Nerves, Peking University Third Hospital, 49 North Garden Road, Haidian District, 100191, Beijing, China
| | - Yu Zhang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Restoration of Damaged Ocular Nerves, Peking University Third Hospital, 49 North Garden Road, Haidian District, 100191, Beijing, China
| | - Yueguo Chen
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China. .,Beijing Key Laboratory of Restoration of Damaged Ocular Nerves, Peking University Third Hospital, 49 North Garden Road, Haidian District, 100191, Beijing, China.
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Ibrahim Al-Mashahedah AM, Kanwar RK, Kanwar JR. Utility of nanomedicine targeting scar-forming myofibroblasts to attenuate corneal scarring and haze. Nanomedicine (Lond) 2019; 14:1049-1072. [DOI: 10.2217/nnm-2017-0305] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Corneal scarring refers to the loss of normal corneal tissue, replaced by fibrotic tissue (during wound repair) thereby affecting corneal transparency and vision quality. The corneal wound healing process involves a complex series of physiological events resulting in the transformation of transparent keratocytes into opaque myofibroblasts; the prominent cause of irregular extracellular matrix synthesis leading to the development of corneal opacity/hazy vision. Globally, corneal scarring/haze is one of the most prevalent causes of blindness. Ocular trauma (physical and chemical) and microbial infections induce corneal tissue damage. Although great progress has been made in the clinical management of ocular diseases, the global rates of corneal blindness remain high, nonetheless. The topical conventional modalities treating corneal wounds/injuries have inherent limitations/side effects such as low bioavailability of a therapeutic agent, upregulation of the intraocular pressure and the toxicity/allergy of the drug. These limitations/side effects rather than treating the wound, often negatively affect the healing process, especially, when applied frequently for longer periods. Recently, there has been an increasing evidence provided by the preclinical studies that nanotechnology-based drug-delivery systems can improve drug bioavailability, through controlled drug release and targeted delivery. After reviewing the epidemiology, risk factors of corneal scarring/haze and the conventional ocular medicines, we review here the different nanodrug-delivery systems and potential drug candidates including nanoherbal formulations investigated for their efficacy to heal the damaged cornea. Finally, we discuss the challenges of using these nanomedicinal platforms.
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Affiliation(s)
- Aseel Mahmood Ibrahim Al-Mashahedah
- Nanomedicine-Laboratory of Immunology & Molecular Biomedical Research (NLIMBR), School of Medicine (SOM), Faculty of Health, Deakin University, Waurn Ponds, Geelong 3216, Australia
| | - Rupinder Kaur Kanwar
- Nanomedicine-Laboratory of Immunology & Molecular Biomedical Research (NLIMBR), School of Medicine (SOM), Faculty of Health, Deakin University, Waurn Ponds, Geelong 3216, Australia
| | - Jagat Rakesh Kanwar
- Nanomedicine-Laboratory of Immunology & Molecular Biomedical Research (NLIMBR), School of Medicine (SOM), Faculty of Health, Deakin University, Waurn Ponds, Geelong 3216, Australia
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Ang BCH, Foo RCM, Lim EWL, Tan MMH, Nah GKM, Thean LSY, Tan CWT, Zhao PSB. Risk factors for early-onset corneal haze after photorefractive keratectomy in an Asian population: Outcomes from the Singapore Armed Forces Corneal Refractive Surgery Programme 2006 to 2013. J Cataract Refract Surg 2018; 42:710-6. [PMID: 27255247 DOI: 10.1016/j.jcrs.2016.01.047] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 01/06/2016] [Accepted: 01/26/2016] [Indexed: 11/26/2022]
Abstract
PURPOSE To assess the incidence and risk factors for early corneal haze after myopic photorefractive keratectomy (PRK). SETTING Tertiary eye center, Singapore. DESIGN Retrospective case series. METHODS The refractive results and corneal haze severity 3 months after PRK were analyzed. Eyes were categorized into 4 groups based on haze severity. Multivariate ordinal logistic regression analysis adjusting for age, ethnicity, sex, use of intraoperative mitomycin-C (MMC), preoperative sphere, and preoperative cylinder was performed. RESULTS The study reviewed data from 177 patients (347 eyes) with a mean age of 22.6 years ± 4.1 (SD). The majority of the patients were Chinese (98.3%) and men (98.3%). The mean preoperative spherical equivalent (SE) was -3.34 ± 1.19 diopters (D). One hundred thirty-five eyes (38.9%) had PRK with MMC. Ten eyes (2.9%) had enhancement surgery. The overall efficacy index was 0.88 and the safety index was 1.07. At 3 months, 187 eyes (53.9%) had no haze, 76 eyes (21.9%) had a haze grade of more than 0 and less than 1, 76 eyes (21.9%) had a haze grade of 1 or more and less than 2, and 8 eyes (2.3%) had grade 2 haze. Higher degrees of myopia (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.13-1.63; P = .001) and astigmatism (OR, 1.56; 95% CI, 1.09-2.24; P = .014) were associated with increased severity of corneal haze, whereas older age (OR, 0.94; 95% CI, 0.88-0.99; P = .023) had a protective effect. CONCLUSION Myopia and astigmatism were associated with increased severity of haze, and older age was protective against early corneal haze development after PRK in an Asian population. FINANCIAL DISCLOSURE None of the authors has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Bryan Chin Hou Ang
- From the Vision Performance Centre (Ang, Lim, Nah, Tan, Zhao), the Military Medicine Institute, Singapore Armed Forces, National Healthcare Group Eye Institute (Ang), Tan Tock Seng Hospital, the Singapore National Eye Centre (Foo), the DSO National Laboratories (Tan), Defence Medical and Environmental Research Institute, the W Eye Clinic (Nah), the Department of Ophthalmology (Nah, Thean, Tan, Zhao), the National University Health System, and the Department of Ophthalmology (Thean), Jurong Health Services, Singapore
| | - Reuben Chao Ming Foo
- From the Vision Performance Centre (Ang, Lim, Nah, Tan, Zhao), the Military Medicine Institute, Singapore Armed Forces, National Healthcare Group Eye Institute (Ang), Tan Tock Seng Hospital, the Singapore National Eye Centre (Foo), the DSO National Laboratories (Tan), Defence Medical and Environmental Research Institute, the W Eye Clinic (Nah), the Department of Ophthalmology (Nah, Thean, Tan, Zhao), the National University Health System, and the Department of Ophthalmology (Thean), Jurong Health Services, Singapore
| | - Edmund Wei Long Lim
- From the Vision Performance Centre (Ang, Lim, Nah, Tan, Zhao), the Military Medicine Institute, Singapore Armed Forces, National Healthcare Group Eye Institute (Ang), Tan Tock Seng Hospital, the Singapore National Eye Centre (Foo), the DSO National Laboratories (Tan), Defence Medical and Environmental Research Institute, the W Eye Clinic (Nah), the Department of Ophthalmology (Nah, Thean, Tan, Zhao), the National University Health System, and the Department of Ophthalmology (Thean), Jurong Health Services, Singapore
| | - Mellisa Mei Hui Tan
- From the Vision Performance Centre (Ang, Lim, Nah, Tan, Zhao), the Military Medicine Institute, Singapore Armed Forces, National Healthcare Group Eye Institute (Ang), Tan Tock Seng Hospital, the Singapore National Eye Centre (Foo), the DSO National Laboratories (Tan), Defence Medical and Environmental Research Institute, the W Eye Clinic (Nah), the Department of Ophthalmology (Nah, Thean, Tan, Zhao), the National University Health System, and the Department of Ophthalmology (Thean), Jurong Health Services, Singapore
| | - Gerard Kwang Ming Nah
- From the Vision Performance Centre (Ang, Lim, Nah, Tan, Zhao), the Military Medicine Institute, Singapore Armed Forces, National Healthcare Group Eye Institute (Ang), Tan Tock Seng Hospital, the Singapore National Eye Centre (Foo), the DSO National Laboratories (Tan), Defence Medical and Environmental Research Institute, the W Eye Clinic (Nah), the Department of Ophthalmology (Nah, Thean, Tan, Zhao), the National University Health System, and the Department of Ophthalmology (Thean), Jurong Health Services, Singapore
| | - Lennard See Yin Thean
- From the Vision Performance Centre (Ang, Lim, Nah, Tan, Zhao), the Military Medicine Institute, Singapore Armed Forces, National Healthcare Group Eye Institute (Ang), Tan Tock Seng Hospital, the Singapore National Eye Centre (Foo), the DSO National Laboratories (Tan), Defence Medical and Environmental Research Institute, the W Eye Clinic (Nah), the Department of Ophthalmology (Nah, Thean, Tan, Zhao), the National University Health System, and the Department of Ophthalmology (Thean), Jurong Health Services, Singapore
| | - Clement Woon Teck Tan
- From the Vision Performance Centre (Ang, Lim, Nah, Tan, Zhao), the Military Medicine Institute, Singapore Armed Forces, National Healthcare Group Eye Institute (Ang), Tan Tock Seng Hospital, the Singapore National Eye Centre (Foo), the DSO National Laboratories (Tan), Defence Medical and Environmental Research Institute, the W Eye Clinic (Nah), the Department of Ophthalmology (Nah, Thean, Tan, Zhao), the National University Health System, and the Department of Ophthalmology (Thean), Jurong Health Services, Singapore
| | - Paul Song Bo Zhao
- From the Vision Performance Centre (Ang, Lim, Nah, Tan, Zhao), the Military Medicine Institute, Singapore Armed Forces, National Healthcare Group Eye Institute (Ang), Tan Tock Seng Hospital, the Singapore National Eye Centre (Foo), the DSO National Laboratories (Tan), Defence Medical and Environmental Research Institute, the W Eye Clinic (Nah), the Department of Ophthalmology (Nah, Thean, Tan, Zhao), the National University Health System, and the Department of Ophthalmology (Thean), Jurong Health Services, Singapore.
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