scholarly journals Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications

2017 ◽  
Vol 11 (1) ◽  
pp. 176-193 ◽  
Author(s):  
Renato Ambrósio, Jr ◽  
Fernando Faria Correia ◽  
Bernardo Lopes ◽  
Marcella Q. Salomão ◽  
Allan Luz ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Front Surface ◽  
Corneal Biomechanics ◽  
Screening Tests ◽  
3D Tomography ◽  
Biomechanical Assessment ◽  
Current State ◽  
Corneal Refractive Surgery ◽  
Corneal Shape ◽  
The Impact

Background:Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea.Method:The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea.Conclusions:The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy.

scholarly journals Experiment on PMMA models to predict the impact of corneal refractive surgery on corneal shape: Comment

2007 ◽  
Vol 15 (12) ◽  
pp. 7243 ◽  
Author(s):  
José R. Jiménez ◽  
Francisco Rodríguez-Marín ◽  
Rosario G. Anera ◽  
Luis Jiménez del Barco
Keyword(s):  
Refractive Surgery ◽  
Corneal Refractive Surgery ◽  
Corneal Shape ◽  
The Impact

scholarly journals Experiments on PMMA models to predict the impact of corneal refractive surgery on corneal shape

2006 ◽  
Vol 14 (13) ◽  
pp. 6142 ◽  
Author(s):  
Carlos Dorronsoro ◽  
Daniel Cano ◽  
Jesús Merayo-Lloves ◽  
Susana Marcos
Keyword(s):  
Refractive Surgery ◽  
Corneal Refractive Surgery ◽  
Corneal Shape ◽  
The Impact

Sjogren Syndrome and Dry Eye: The Impact of Corneal Refractive Surgery

Cornea ◽  
2010 ◽  
Vol 29 (9) ◽  
pp. 1072 ◽  
Author(s):  
Patrick M K Tam ◽  
Alvin L Young ◽  
Philip T H Lam
Keyword(s):  
Dry Eye ◽  
Refractive Surgery ◽  
Sjögren Syndrome ◽  
Sjogren Syndrome ◽  
Corneal Refractive Surgery ◽  
The Impact

scholarly journals A multicenter study of the distribution pattern of posterior corneal astigmatism in Chinese myopic patients having corneal refractive surgery

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yijun Hu ◽  
Shanqing Zhu ◽  
Lu Xiong ◽  
Xuejun Fang ◽  
Jia Liu ◽  
...  
Keyword(s):  
Image Quality ◽  
Distribution Pattern ◽  
Multicenter Study ◽  
Refractive Surgery ◽  
Corneal Astigmatism ◽  
Astigmatism Correction ◽  
Corneal Refractive Surgery ◽  
The Impact ◽  
Anterior Corneal Astigmatism ◽  
Posterior Corneal Astigmatism

Abstract Including posterior corneal astigmatism (PCA) into consideration may increase the accuracy of astigmatism correction after corneal refractive surgery. In the present study we aim to investigate the distribution pattern of PCA in a large number of myopic patients from multiple ophthalmic centers. There were 7829 eyes retrospectively included in the study. Pentacam data of the eyes were retrieved from the machine and only results with image quality labelled with ‘OK’ were included. Distribution of PCA was slightly positively skewed (Skewness = 0.419, Kurtosis = 0.435, KS P < 0.0001). Mean PCA was 0.34 ± 0.14 D (range: 0.00 D-0.99 D). PCA was ≥ 0.25 D in 74.91% of the eyes and was ≥ 0.50 D in 11.61% of the eyes. In 97.55% of the eyes the steep meridian of PCA was vertical (SMV). PCA magnitude was significantly higher in eyes with SMV PCA (P < 0.0001) or high manifest astigmatism (MA, P < 0.0001). There was a significant correlation between anterior corneal astigmatism (ACA) magnitude and PCA magnitude in all of the eyes (r = 0.704, P < 0.0001). There was also a trend of decreasing frequency and magnitude of SMV PCA with aging (both P < 0.0001). In conclusion, PCA is present in myopic patients having corneal refractive surgery and PCA magnitude is increased with higher MA or ACA. Consideration of the impact of PCA on laser astigmatism correction may be necessary.

scholarly journals Analysis of Corneal Refractive Surgery in Soldiers from a Specific Region, China

2020 ◽  
Author(s):  
Wei-Yang Shao ◽  
Hong-Zhen Jia ◽  
Bei Cui ◽  
Li-Qun Cao ◽  
Li-Wei Qin ◽  
...  
Keyword(s):  
Physical Examination ◽  
Refractive Surgery ◽  
Specific Region ◽  
Laser In Situ Keratomileusis ◽  
Low Grade ◽  
Slit Lamp ◽  
Slit Lamp Examination ◽  
History Of ◽  
Corneal Refractive Surgery ◽  
The Impact

Abstract Background: Increasing numbers of young people of the appropriate age are joining the army after vision improvement by refractive surgery. However, there is little research on the long-term influence of this population and the potential impact on mission capability. Methods: A cluster sampling survey was conducted. The respondents were soldiers who planned to apply for military academies in a specific region of China in 2020. According to the Physical Examination Standards for Citizens Eligible for Enlistment and the Physical Examination Law for Citizens Eligible for Enlistment, a medical history inquiry, vision examination, color vision examination, slit-lamp examination, and personal interview were performed to obtain information regarding the patients' preoperative myopia, corneal refractive surgery method used, operation time, and symptoms of postoperative discomfort. Results: Among the 1263 soldiers who underwent the physical examination, 435 soldiers (862 eyes) had a history of corneal refractive surgery, accounting for 34.44%. Among the soldiers with a history of corneal refractive surgery, the treatment of preoperative low-grade myopia accounted for 41.61%, moderate-grade myopia accounted for 43.68%, and high-grade myopia accounted for 14.71%. Regarding the surgical methods used, small incision lenticule extraction (SMILE) accounted for 23.44%, excimer laser in situ keratomileusis (LASIK) accounted for 66.67%, and trans-epithelial photorefractive keratectomy (PRK) accounted for 9.89%. The postoperative time was 2.76 ± 1.01 years. Soldiers with uncorrected visual acuity (UCVA) ≤ 4.9 accounted for 3.94%, and soldiers with UCVA > 4.9 accounted for 96.06%. Slit-lamp examination found no surgical complications affecting visual function, such as dry eye syndrome, corneal infection, corneal haze (above grade 3), and corneal epithelial implantation. Conclusion: The proportion of soldiers who have undergone corneal refractive surgery has significantly increased, and LASIK is the main surgical method used. The impact of complications related to corneal refractive surgery on the army should be emphasized, and health education and reasonable training should be strengthened to avoid eye-related diseases.

Sign in / Sign up

Export Citation Format

Share Document