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2.
Zhonghua Yan Ke Za Zhi ; 56(2): 103-109, 2020 Feb 11.
Artigo em Chinês | MEDLINE | ID: mdl-32074820

RESUMO

Objective: To investigate the application value of Pentacam combined with Corvis ST in evaluation of the changes of corneal biomechanics after femtosecond laser small incision lenticule extraction (SMILE) in Chinese myopia with an irregular cornea. Methods: The clinical records for 104 eyes of 57 patients who received SMILE in the Refractive Center of Beijing Tongren Hospital during January 2018 and May 2018 were collected. According to the keratoconus severity index (KSI), they were divided into two groups: regular corneal group (KSI<15%) and irregular corneal group (KSI: 15% to 25%). In both groups, the anterior corneal surface radius curvature was>7.25 mm (K<46.50 diopters), the posterior corneal surface radius curvature was>5.90 mm, the thinnest pachymetry was>490 µm, and best corrected visual acuity was ≥1.0. The vision, refraction, and corneal biomechanics before and after SMILE were assessed. The Topographic and Biomechanics Index (TBI) was analyzed by Pentacam combined with Corvis ST. Results: Before SMILE, the Corvis Biomechanical Index (CBI), TBI, and Belin/Ambrósio Deviation Normalized Index (BADD) of the irregular corneal group were significantly higher (t=-2.17, -6.78, -4.37, P<0.05) than the regular corneal group, while the stiffness parameter (SPA1) was significantly lower (t=2.58, P=0.011) compared to the regular corneal group (P<0.05). In the irregular group, the TBI was (0.28±0.2); the maximum value was 0.03, and the minimum value was 0.43. The CBI was (0.09±0.21); the maximum value was 0.00, and the minimum value was 0.54. The BADD was (1.33±0.47); the maximum value was 0.42, and the minimum value was 2.26. In the regular group, the TBI was (0.05±0.08); the maximum value was 0.00, and the minimum value was 0.20. The CBI was (0.01±0.03); the maximum value was 0.00, and the minimum value was 0.17. The BADD was (0.92±0.46); the maximum value was 0.00, and the minimum value was 1.64. There was no significant difference between two groups in age (t=0.20, P=0.508), central corneal thickness (t=1.64, P=0.104), biomechanical corrected IOP (t=0.73, P=0.468), max inverse radius (t=-0.24, P=0.815), spherical equivalent (t=-0.97, P=0.335), and best corrected visual acuity (t=0.21, P=0.833). After SMILE, the deformation amplitude in the irregular group was significantly higher at 1 month and 3 months (t=-3.13, -3.09, P<0.05). The irregular group had a significantly higher deformation amplitude ratio at 1 week, 1 month, and 1 year (t=-2.72, -3.39, -2.51, P<0.05). The SPA1 in the irregular group was significantly lower than the regular group at 1 week, 1 month, and 3 months (t=2.11, 2.73, 3.70, P=0.335, 0.010,<0.001). The changes of deformation amplitude (t=0.50, -1.10, -0.73, 2.12, P>0.05), max inverse radius (t=-1.52, -1.41, 0.01, -0.79, P>0.05), and SPA1(t=0.89, 0.90, 1.12, 0.90, P>0.05) after SMILE were similar between the irregular and regular groups, except that at 1 month after SIMILE, the deformation amplitude ratio changed more significantly in the irregular group (t=-3.01, P=0.003). Conclusions: The changes of corneal biomechanics in the groups of regular cornea and irregular cornea were stable with no significant difference during 1 year of post-SMILE. The diagnosis based on the corneal topography and corneal biomechanics is of certain significance for the screening of early keratoconus before keratorefractive surgery. (Chin J Ophthalmol, 2020, 56:103-109).


Assuntos
Córnea , Ceratocone , Miopia , Fenômenos Biomecânicos , Córnea/fisiologia , Córnea/cirurgia , Substância Própria , Topografia da Córnea , Humanos , Acuidade Visual
3.
Zhonghua Yan Ke Za Zhi ; 56(1): 47-52, 2020 Jan 11.
Artigo em Chinês | MEDLINE | ID: mdl-31937063

RESUMO

Objective: To compare the keratometric measurements of the Verion image guided system with the partial coherence interferometry (IOLMaster700) and the scheimpflug corneal topography (Pentacam). Methods: In this cross-sectional study, 146 eyes of 88 patients [mean age, (69±10) years; 62 eyes of male patients and 84 eyes of female patients] with cataract were examined before cataract extraction and IOL implantation surgery in the Tenth People's Hospital Affiliated to Tongji University from January 2016 to March 2017. Corneal curvature values acquired by the Verion optical imaging system were compared with the IOLMaster700 and the Pentacam. Keratometric data, magnitude of astigmatism, and steep astigmatic axis measurements from all three instruments were also compared. According to the steep axis of astigmatism, the eyes were divided into groups of with the rule (WTR), against the rule (ATR), and oblique astigmatism. The parameter differences between the Verion and the other devices in the three groups were analyzed. The data were evaluated using repeated measures analysis of variance and Bland-Altman plots. Results: The values of steep keratometry (Ks) of the Verion, IOLMaster700, and Pentacam were (44.60±1.32), (44.73±1.37), (44.43±1.35) D, respectively. The values of flat keratometry (Kf) of the Verion, IOLMaster700, and Pentacam were (43.51±1.41), (43.51±1.52), (43.40±1.45) D, respectively. The values of mean keratometry (Km) of the Verion, IOLMaster700, and Pentacam were (44.60±1.32), (44.12±1.35), (43.92±1.34) D, respectively. The values of astigmatism magnitude were (1.09±0.87), (1.24±1.02), (1.04±0.80) D, respectively. The F values were 1.81, 0.31, 0.93 and 2.22 in relation to Ks, Kf, Km and corneal astigmatism magnitude among the three instruments, respectively (all P>0.05). The 95% confidence intervals of Kf, Ks and astigmatism magnitude between the Verion and the other two devices were -1.10 to 0.80 D, -0.55 to 0.88 D; -1.10 D to 1.10 D, -0.80 to 1.04 D; -1.21 to 0.90 D, -0.92 to 1.02 D. The outcomes were considered acceptable. There were no statistically differences in steep astigmatic axis measurements between the Verion and the other two instruments among the WTR (62 eyes), ATR (45 eyes) and oblique (15 eyes) groups (F=0.63, 0.37; P=0.54, 0.72, respectively). Conclusions: The Verion image guided system is a reliable system for the measurement of keratometry values and astigmatism. The keratometric power, magnitude and steep axis of astigmatism have no significant difference, and there is a good agreement among the Verion, IOL Master 700, and Pentacam. (Chin J Ophthalmol, 2020, 56: 47-52).


Assuntos
Astigmatismo/diagnóstico , Comprimento Axial do Olho , Biometria/instrumentação , Catarata/complicações , Córnea/patologia , Topografia da Córnea , Imagem Óptica/instrumentação , Idoso , Idoso de 80 Anos ou mais , Extração de Catarata , Estudos Transversais , Feminino , Humanos , Lentes Intraoculares , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Cirurgia Assistida por Computador
4.
Eur J Ophthalmol ; 30(1): 139-146, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30541357

RESUMO

IMPORTANCE: This study shows that a newer long-arc length intrastromal corneal ring segment is efficient and safe for keratoconus treatment. BACKGROUND: To evaluate visual, tomographic results and complications of a 320-degree intrastromal corneal ring segment implantation with the femtosecond laser for keratoconus treatment. DESIGN: A prospective, nonrandomized, and interventional study. PARTICIPANTS: A total of 34 eyes of 31 patients diagnosed with keratoconus were enrolled. METHODS: Patients were divided into two groups based on the strategy used for 320-degree intrastromal corneal ring segment thickness selection. In one group, this selection was based on spherical equivalent (SE group) and in the other on the mean asphericity (Q group). The uncorrected and corrected distance visual acuities, spherical equivalent, K1, K2, Km, Kmax, and mean asphericity (Q) on corneal tomography were evaluated preoperatively and at 3 and 6 months postoperatively. For astigmatism improvement, we analyzed the corneal tomographic vectorial astigmatism change preoperatively and at 6 months postoperatively. The mean follow-up period was 6.63 ± 0.96 months. RESULTS: The mean uncorrected distance visual acuity and corrected distance visual acuity improved with a significant spherical equivalent improvement (p < 0.05), with no differences between the 320-degree intrastromal corneal ring segment groups. All corneal tomographic parameters improved significantly (p < 0.05) between the preoperative and postoperative intervals, with a significant better performance when we used spherical equivalent for the 320-degree intrastromal corneal ring segment thickness selection. Finally, the mean vectorial corneal tomographic astigmatism significantly improved after 6 months, again with no differences between groups. CONCLUSION: This study suggests that implanting a 320-degree intrastromal corneal ring segment is a safe and effective procedure for treating patients with keratoconus. It also suggests that for thickness selection spherical equivalent is the better strategy.


Assuntos
Substância Própria/cirurgia , Ceratocone/cirurgia , Implante de Lente Intraocular/métodos , Refração Ocular/fisiologia , Acuidade Visual , Adolescente , Adulto , Criança , Substância Própria/patologia , Topografia da Córnea , Feminino , Seguimentos , Humanos , Ceratocone/diagnóstico , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Estudos Prospectivos , Desenho de Prótese , Fatores de Tempo , Adulto Jovem
5.
Eur J Ophthalmol ; 30(1): 104-111, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30328359

RESUMO

PURPOSE: The purpose of this study is to evaluate the effects of variation in tunnel length of same-sized clear corneal phacoemulsification incisions on the generation of surgically induced astigmatism and corneal astigmatism. METHODS: A total of 126 cataract patients treated in four study groups based on location and tunnel length of the clear corneal incisions (superior long, superior short, temporal long, temporal short) were reviewed. In the short tunnel groups, a 2.8 mm keratome was used with a motion parallel to the iris surface, while in the long tunnel groups, the same keratome was advanced in the corneal stroma until the mark on the keratome was reached. The surgically induced astigmatism and the corneal astigmatism were measured with corneal topography. The tunnel lengths were determined by anterior segment optical coherence tomography. RESULTS: The tunnel lengths of the long tunnel groups were significantly longer than the short tunnel groups. The total and anterior corneal surgically induced astigmatism of the superior long group was significantly higher than the other groups. Posterior corneal surgically induced astigmatism was similar. The postoperative total and anterior corneal astigmatism values of the superior long group was significantly higher than the other groups. No difference was observed for mean change in corneal astigmatism between the groups. CONCLUSION: The tunnel length of a clear corneal incision is a significant determinant of surgically induced astigmatism for superior placed corneal incisions. Therefore, for superiorly positioned clear corneal incision, the incision should be rectangular with a shorter tunnel to keep the surgically induced astigmatism to a minimum. For squarer-shaped clear corneal incision, limbal-temporal incisions may be performed for astigmatic neutrality.


Assuntos
Segmento Anterior do Olho/patologia , Astigmatismo/diagnóstico , Topografia da Córnea/métodos , Facoemulsificação/efeitos adversos , Complicações Pós-Operatórias/diagnóstico , Tomografia de Coerência Óptica/métodos , Astigmatismo/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia
6.
Eur J Ophthalmol ; 30(1): 125-131, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30384777

RESUMO

PURPOSE: To evaluate the visual, refractive, topographic, pachymetric, and biomechanical outcomes after intracorneal ring segment implantation in corneas with post-LASIK ectasia. METHODS: Retrospective longitudinal study enrolling 26 eyes of 22 patients with post-LASIK ectasia and undergoing intracorneal ring segment implantation (KeraRing®, Mediphacos) using a 60-kHz femtosecond laser (IntraLase®, IntraLase Corp.) for corneal tunnelization. Visual, refractive, anterior, and posterior corneal topographic (Pentacam HR, Oculus), pachymetric, and corneal biomechanical changes (Ocular response Analyzer, Reichert) were evaluated during a 12-month follow-up. Vector analysis of astigmatic changes was performed. RESULTS: A statistically significant reduction of sphere (p = 0.043) was observed at 1 month after surgery, with a significant improvement of uncorrected distance visual acuity associated (p = 0.019). Likewise, a significant reduction of anterior corneal power measurements (p ⩽ 0.014) and steepest posterior keratometric reading (p = 0.006) were observed at 1 month postoperatively, with no significant changes afterwards (p ⩾ 0.133). No significant changes were observed in manifest cylinder (p ⩾ 0.175), corrected distance visual acuity (p ⩾ 0.174), flattest posterior keratometric measurement (p ⩾ 0.282), volumetric measurements (p ⩾ 0.051), and corneal biomechanical parameters (p ⩾ 0.068). Vector analysis revealed an initial trend to overcorrection of astigmatism, with a trend to undercorrection at the end of follow-up and a significant variability in the outcome achieved in each patient. CONCLUSION: The implantation of KeraRing segments in post-LASIK corneal ectasia generates a significant modification of spherical refraction and a visual improvement due to a central corneal flattening generated. More refined nomograms of implantation in these cases should be developed to achieve a more predictable correction of astigmatism.


Assuntos
Córnea/cirurgia , Doenças da Córnea/cirurgia , Cirurgia da Córnea a Laser/efeitos adversos , Implante de Lente Intraocular/métodos , Complicações Pós-Operatórias/cirurgia , Refração Ocular/fisiologia , Acuidade Visual , Adulto , Córnea/patologia , Doenças da Córnea/diagnóstico , Doenças da Córnea/etiologia , Topografia da Córnea , Dilatação Patológica/diagnóstico , Dilatação Patológica/cirurgia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/patologia , Desenho de Prótese , Reoperação , Estudos Retrospectivos
7.
Zhonghua Yan Ke Za Zhi ; 55(12): 904-910, 2019 Dec 11.
Artigo em Chinês | MEDLINE | ID: mdl-31874503

RESUMO

Objective: To study the safety and efficacy of topography-guided customized excimer laser subepithelial ablation combined with accelerated collagen cross-linking technique in treatment of early keratoconus. Methods: Ninteen patients(20 eyes) (13 males 14 eyes, and 6 females 6 eyes), aged 12 to 44 years (24.7±8.0) were diagnosed as keratoconus by three-dimensional corneal topography and tomography, clinical history and examinations, and classified as KC1~KC3. Based on the classical excimer laser subepithelial keratomileusis (LASEK) method, topography guided laser ablation was performed with an excimer laser system (WaveLight EX500). After laser ablation, the corneal stromal bed was immersed with 0.1% riboflavin for 10 minutes, and then was irradiated by ultraviolet light (Avedro KXL) at 30 mW/cm(2) for 4 minutes. All the patients were followed up for more than 12 months. The uncorrected visual acuity (UCVA), diopter, best corrected visual acuity (BSCVA), corneal topography, central corneal endothelial cell density (ECD), hexagonal cell percentage (HEX), coefficient of variation (CV) and other indicators were observed. For normal distribution variables, Dunnett-t test was used before and after operation, and Wilcoxon test was used for variables with abnormal distribution. And the complications were recorded. Results: There was no loss of BSCVA at 12 months postoperatively, 20% of the eyes had no change of BSCVA, and 15% of the eyes gained 1 line of BSCVA, 15% of the eyes gained 2 lines of BSCVA, 50% of the eyes gained 3 lines and more of BSCVA. There was no significant difference in UCVA, BSCVA, manifest refractive spherical equivalent (MRSE) and the cylinder at 3 months postoperatively (P>0.05). The BSCVA were significantly improved at 6 and 12 months postoperatively compared with those before operation (t=3.095, 3.079, <0.05). Although there was no significant difference in UCVA and MRSE, the cylinder was significantly reduced at 6 and 12 months postoperatively (t=-2.890, -2.435, P<0.05). Apex curvature (Kapex) and mean pupil power (MPP) within 4.5mm of central cornea decreased significantly (Z=-2.903, P<0.01; Z=-2.667, P<0.01). Even though the thinnest corneal thickness decreased from pre-operational (461.9±31.1) µm to post-operational (416.6±27.0) µm (Z=-3.059, P<0.01), the cornea became regular with keratometric asymmetry index of anterior corneal surface decreased (Z=-2.667, P<0.01). The corneal optical quality parameters were improved. There was no significant difference in ECD, HEX and CV at 12 months postoperatively (P>0.05). Twelve months after operation, grade 0, 0.5, 1 and 2 haze were seen on 20%, 55%, 20% and 5% corneas respectively. Conclusions: The topography guided excimer laser ablation combined with accelerated corneal collagen cross linking is safe and effective in treatment of early stage keratoconus. It can significantly improve corneal regularity while preventing keratoconus progression, so as to improve the best corrected visual acuity postoperatively. (Chin J Ophthalmol, 2019, 55: 904-910).


Assuntos
Ceratocone , Terapia a Laser , Adolescente , Adulto , Criança , Colágeno , Córnea , Substância Própria , Topografia da Córnea , Reagentes para Ligações Cruzadas , Feminino , Humanos , Ceratocone/terapia , Masculino , Fármacos Fotossensibilizantes , Raios Ultravioleta , Adulto Jovem
8.
Zhonghua Yan Ke Za Zhi ; 55(12): 911-915, 2019 Dec 11.
Artigo em Chinês | MEDLINE | ID: mdl-31874504

RESUMO

Objective: To investigate the diagnosis of normal cornea, subclinical keratoconus and keratoconus by artifical intelligence. Methods: Diagnostic study. From January 2016 to January 2019, who admitted to Tianjin Eye Hospital from 18 to 48 years old, with an average of (28.4±8.2) years of myopia patients in 2 018 cases. Two experienced ophthalmologists labeled keratoconus, subclinical keratconus and nomal cornea based on the topography. The data of 80% (1 615 cases) patients were randomly selected as the training set by computer random sampling method, and the data of 20% (403 cases) patients were used as the verification set. Using the Gradient Boosting Decision Tree (GBDT) algorithm to extract 28 corneal parameters, and establish an algorithm model to diagnose the corneal condition of the patient, verify the diagnostic accuracy of the model by using the 10-fold cross-validation method, and evaluate the model using the receiver operating characteristic curve. Sensitivity and specificity with the original labeling and ophthalmic resident labeling. Results: The diagnostic accuracy of the model was 95.53%. The area under the receiver operating characteristic curve (AUC) of the validation set was 0.996 6. The accuracy of the model for diagnosis of subclinical keratoconus and normal cornea was 96.67%, the AUC of the validation set was 0.993 6; the accuracy of diagnosis of keratoconus and normal cornea was 98.91%, and the AUC of the validation set was 0.998 2. The diagnostic accuracy of the model is 95.53%, which is significantly better than the resident's 93.55%. Conclusion: The model established by artifical intelligence can diagnose the subclinical keratoconus with high accuracy, which can greatly improve the clinical diagnosis efficiency and accuracy of young and primary ophthalmologists. (Chin J Ophthalmol, 2019, 55: 911-915).


Assuntos
Inteligência Artificial , Paquimetria Corneana , Topografia da Córnea , Ceratocone , Adolescente , Adulto , Córnea , Humanos , Ceratocone/diagnóstico , Pessoa de Meia-Idade , Curva ROC , Sensibilidade e Especificidade , Adulto Jovem
9.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 36(6): 1018-1023, 2019 Dec 25.
Artigo em Chinês | MEDLINE | ID: mdl-31875377

RESUMO

In the evaluation of tear film stability based on corneal topography, a pretreatment algorithm for tear film video was proposed for eye movement, eyelash reflection and background interference. First, Sobel operator was used to detect the blur image. Next, the target image with highlighted ring pattern was obtained by the morphological open operation performed on the grayscale image. Then the ring pattern frequency of the target image was extracted through the Hough circle detection and fast Fourier transform, and a band-pass filter was applied to the target image according to the ring pattern frequency. Finally, binarization and morphological closed operation were used for the localization of the ring pattern. Ten tear film videos were randomly selected from the database and processed frame by frame through the above algorithm. The experimental results showed that the proposed algorithm was effective in removing the invalid images in the video sequence and positioning the ring pattern, which laid a foundation for the subsequent evaluation of tear film stability.


Assuntos
Córnea , Lágrimas , Algoritmos , Topografia da Córnea
15.
Vestn Oftalmol ; 135(5. Vyp. 2): 171-176, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31691656

RESUMO

INTRODUCTION: According to various sources, occurrence rate of keratectasia (KE) after Laser in situ Keratomileusis (LASIK) ranges from 0.04 to 0.2%. No known technique for keratorefractive surgery eliminates the probability. Neither corneal cross-linking, nor implantation of polymeric segments can completely prevent its development. PURPOSE: To treat KE after LASIK with bandage lamellar-optical keratoplasty (BLOK) surgery and to evaluate the results. MATERIAL AND METHODS: The study included 22 patients with KE after LASIK divided into two groups. The first group consisted of 6 patients; they underwent BLOK surgery using a segment transplant 1.5 mm in width and 180-220 µm in thickness. The second group included 16 patients who underwent BLOK surgery using 2.75 mm wide, 290-350 µm thick allogeneic transplant of individual length. The follow-up lasted 4 years. RESULTS: In the first group, uncorrected visual acuity (UCVA) improved by 0.4±007, in the second group - by 0.46±0.15. After two years, two patients had their transplant exchanged for a wider one due to ectasia progression. Corneal refraction was stable at 45.36±1.47 Diopters in all other patients of the first group. In the second group, it was consistently between 40.6 and 45.7 Diopters. The main complication of the BLOK surgery was displacement of the edge of the corneal flap formed during LASIK - occurred in 4 patients. CONCLUSION: Bandage lamellar-optical keratoplasty proved effective in treating patients with KE after LASIK, leading to improvement of visual acuity, strengthening of the cornea and normalization of its surface; it slows further progression of ectasia.


Assuntos
Doenças da Córnea , Transplante de Córnea , Ceratomileuse Assistida por Excimer Laser In Situ , Bandagens , Córnea , Topografia da Córnea , Dilatação Patológica , Humanos , Lasers de Excimer , Complicações Pós-Operatórias
16.
Asia Pac J Ophthalmol (Phila) ; 8(5): 385-390, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31567265

RESUMO

The advent of "flapless" small-incision lenticule extraction (SMILE), employing all-in-one technology, has resulted in a revolutionary breakthrough in refractive surgeries. SMILE has been gaining popularity due to fewer potential complications, such as postoperative dry eyes and greater biomechanical stability, etc. However, attention must be given to 1) the centration on the corneal vertex, 2) the proper alignment of the astigmatic axis, and 3) the relationship between pupil size and treatment diameter, to achieve good SMILE results. There is no pupil-tracking system to ascertain the accuracy of centration during the SMILE surgery. To improve the centration accuracy, our center uses two corneal topographers (Pentacam and Sirius) to measure and determine corneal vertex. Proper predicted optical zone diameter is not clearly defined yet in SMILE. Some scholars insist that mesopic pupil size should be taken into consideration when setting the predicted optical zone. Meanwhile, the issue of "functional optical zone" still has many unresolved issues and warrants further studies.


Assuntos
Substância Própria/cirurgia , Ceratomileuse Assistida por Excimer Laser In Situ/métodos , Lasers de Excimer/uso terapêutico , Miopia/cirurgia , Refração Ocular/fisiologia , Acuidade Visual , Substância Própria/diagnóstico por imagem , Topografia da Córnea , Humanos , Miopia/diagnóstico , Miopia/fisiopatologia
18.
Artigo em Inglês | MEDLINE | ID: mdl-31614850

RESUMO

Background: Recurrent keratoconus (RKC) develops as a progressive thinning of the peripheral and the inferior cornea after keratoplasty, in both graft and host, causing secondary astigmatism, refractive instability, and reduced visual acuity. We evaluated the effectiveness of corneal cross-linking (CXL) in patients diagnosed with RKC. Methods: Accelerated-CXL via the epi-off technique was performed in15 patients (18 eyes) diagnosed with RKC. Topographic and biomechanical changes were assessed at 12 months. Results: Differences in maximum keratometry, thinnest corneal thickness, and biomechanical parameters (deformation amplituderatio, inverse concave radius, applanation 1 velocity, and applanation 2 velocity, stiffness A1) versus baseline were statistically significant (p < 0.05).Best corrected visual acuity was improved in 13 eyes and unchanged in 4;manifest refractive spherical equivalent was reduced in 13 eyes, increased in 3,and unchanged in 1 eye; topographic astigmatism was reduced in 9 eyes, remained stable in 1 eye, and increased in 7 eyes. Conclusions: Improved topographic and biomechanic indexes at 1 year after CXL suggest it's potential as first-line therapy for RKC, as it is for KC.


Assuntos
Topografia da Córnea/métodos , Reagentes para Ligações Cruzadas/uso terapêutico , Ceratocone/cirurgia , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Adulto , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade
20.
Invest Ophthalmol Vis Sci ; 60(12): 3794-3802, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31525776

RESUMO

Purpose: To provide insight into the mechanism underlying corneal deformation in keratoconus, we examined the relations among corneal curvature, thickness, and volume as well as the association of corneal scar formation with these parameters. Methods: A total of 288 corneas of 174 keratoconus patients and 114 corneas of 57 control subjects were examined by anterior segment-optical coherence tomography (AS-OCT). Anterior and posterior refractive values, corneal thickness (CT), and corneal volume (CV) were determined by AS-OCT for both control and keratoconic eyes. The pattern of corneal stromal scarring was also determined from the AS-OCT images. Results: The distribution of CV was similar for keratoconic and control eyes, whereas anterior and posterior refractive values as well as CT showed a wider distribution for keratoconic eyes. The progression of corneal deformation initially occurred without corneal thinning but was later associated with a decrease in CT and an eventual loss of CV. The progression of scarring from the anterior to the posterior stroma was associated with an increase in anterior refractive value and decreases in posterior refractive value, CT, and CV. Conclusions: The progression of keratoconus as reflected by corneal deformation was associated with a reduction in CT and CV as well as stromal scar formation. The loss of CV occurred after the initial decline in CT, suggesting that stromal degradation occurred only at the advanced stage of keratoconus.


Assuntos
Córnea/patologia , Ceratocone/fisiopatologia , Tomografia de Coerência Óptica , Adolescente , Adulto , Idoso , Segmento Anterior do Olho/diagnóstico por imagem , Lesões da Córnea/patologia , Substância Própria/patologia , Topografia da Córnea , Elasticidade/fisiologia , Feminino , Humanos , Ceratocone/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Refração Ocular/fisiologia , Adulto Jovem
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