scholarly journals Analysis of Corneal Distortion after Myopic PRK

2020 ◽  
Vol 10 (1) ◽  
pp. 82
Author(s):  
Michele Lanza ◽  
Luigi De Rosa ◽  
Sandro Sbordone ◽  
Rosa Boccia ◽  
Ugo Antonello Gironi Carnevale ◽  
...  
Keyword(s):  
Significant Variation ◽  
Refractive Surgery ◽  
Late Onset ◽  
Biomechanical Properties ◽  
Spherical Equivalent ◽  
Corneal Resistance Factor ◽  
Central Surface ◽  
Deformation Parameters ◽  
Corneal Shape

The purpose of the study is to evaluate the corneal biomechanical properties (CBP) and their behaviors after myopic refractive surgery both with Ocular Response Analyzer (ORA) and Corvis ST (CST). This retrospective study included 145 eyes of 145 patients with a mean age of 33.13 ± 9.24 years, who underwent myopic photorefractive keratectomy (PRK) for a refractive defect, measured as spherical equivalent, of mean −4.69 ± 2.04 D and have been evaluated before surgery and at 1, 3 and 6 months follow-up. Corneal hysteresis (CH) and corneal resistance factor (CRF) values significantly decreased after 1 month and remained statistically stable during further follow-ups. CST parameters had a different evolution: only second applanation time (AT2) differences showed a significant variation after 1 month that did not statistically change over time. Highest concavity deformation amplitude (HCDA), highest concavity peak distance (HCPD), first applanation time (AT1) and velocity (AV1) showed continuous significant differences both after 3 and after 6 months. This study suggests that after central surface ablation surgery, such as myopic PRK, corneal shape is remodeling, and its deformation parameters are going to change even at 6 months follow-up. This indicates that it should be important to evaluate refractive surgery patients during a longer follow-up because this could allow earlier diagnosis and better management of late-onset complications.

scholarly journals Simultaneous Phacoemulsification and Graft Refractive Surgery in Penetrating Keratoplasty Eyes

2011 ◽  
Vol 2011 ◽  
pp. 1-5
Author(s):  
Sepehr Feizi ◽  
Mohammad Zare ◽  
Bahram Einollahi
Keyword(s):  
Refractive Surgery ◽  
Penetrating Keratoplasty ◽  
Spherical Equivalent ◽  
Iol Implantation ◽  
Acceptable Accuracy ◽  
Corrected Visual Acuity ◽  
Spherical Equivalent Refraction ◽  
Iol Power ◽  
Relaxing Incisions

Purpose. To report outcomes of graft refractive surgery (GRS) along with clear-cornea phacoemulsification and intraocular lens (IOL) implantation in penetrating keratoplasty (PKP) eyes. Methods. Fourteen eyes of 13 patients who had received PKP underwent simultaneous GRS (relaxing incisions with or without counter-quadrant compression sutures) and clear-cornea phacoemulsification with IOL implantation. To calculate IOL power, preoperative keratometry readings and the SRK-T formula were used. Results. Mean patient age and follow-up period were years and months, respectively. A significant increase was observed in best spectacle-corrected visual acuity (from logMAR to logMAR, ). There was a significant decrease in vector keratometric astigmatism by 6.22 D (). Spherical equivalent refraction was reduced from  D to  D () which did not significantly differ from the target refraction ( D, ). No complications developed and all the grafts remained clear at the final examination. Conclusion. Simultaneous phacoemulsification and GRS is a safe and effective method to address post-PKP astigmatism and lens opacity. IOL power can be calculated from preoperative keratometry readings with an acceptable accuracy. However, patients should be informed about the possibility of high refractive errors postoperatively.

scholarly journals Outcomes of Refractive Surgery Consultations at an Academic Center: Characteristics Associated with Proceeding (or Not Proceeding) with Surgery

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Irene C. Kuo ◽  
Benjamin Lee ◽  
Jiangxia Wang
Keyword(s):  
Refractive Surgery ◽  
Laser In Situ Keratomileusis ◽  
Spherical Equivalent ◽  
Implantable Collamer Lens ◽  
High Patient Satisfaction ◽  
Academic Center ◽  
Johns Hopkins University ◽  
Technological Limitations

Objective. Refractive surgery volume has not rebounded despite economic recovery and literature describing safety, efficacy, and high patient satisfaction. We sought to examine characteristics of consultation seekers and status after consultation. Methods. Charts of patients seeking refractive surgery at Johns Hopkins University from 2013 through 2016 were retrospectively reviewed for age, gender, refractive characteristics, and outcome: surgery (photorefractive keratectomy, laser in-situ keratomileusis, implantable collamer lens, or refractive lens exchange); no surgery—“lost candidate” (good candidates who were lost after consultation); noncandidates based on technological limitations or contraindications; or no surgery—possessing expectations that surgery would not meet. Associations between characteristics and status after consultation were examined. Results. Twenty percent (142/712) of all patients were “lost candidates”; 57% (408/712) completed surgery. More women (56% or 401/712) sought consultation, but a greater percentage (63% or 195/311) of men completed surgery than women did (53% or 213/401) p=0.02. Of consultation seekers, 60% were low myopes, 29% were high myopes (>6 diopters of myopic spherical equivalent), and 11% were hyperopes. Surgical patients’ mean age was 34.2 ± 10.2 (standard deviation) years; for each additional year of age, patients were less likely to have surgery p<0.001. Hyperopes were ≥3 times more likely than myopes to have expectations not met by surgery or to be noncandidates than to have surgery p<0.005. Conclusions. Most patients seeking refractive surgery had 6 diopters or less of myopia. About 20% of patients were lost after consultation; better counseling and follow-up of candidates may be warranted. Expectations and technology limit eligibility for many, especially hyperopes. Low surgery volume may affect training of future refractive surgeons.

scholarly journals Corneal Cross-Linking (with a Partial Deepithelization) in Keratoconus with Five Years of Follow-Up

2016 ◽  
Vol 8 ◽  
pp. OED.S38364 ◽  
Author(s):  
Virgilio Galvis ◽  
Alejandro Tello ◽  
Néstor I. Carreño ◽  
Alvaro I. Ortiz ◽  
Rodrigo Barrera ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Corneal Thickness ◽  
Case Series ◽  
Cross Linking ◽  
Spherical Equivalent ◽  
Corneal Endothelial Cells ◽  
Corneal Resistance Factor ◽  
Endothelial Cell Count ◽  
Corrected Visual Acuity

We performed a retrospective interventional case series including 80 eyes of 48 patients with keratoconus (KC) who were treated with modified corneal cross-linking (CXL) for KC (with a partial deepithelization in a pattern of stripes). The average follow-up was 5.8 years (with a minimum of 5 years). At the last follow-up visit, compared with preoperative values, there were no significant changes in spherical equivalent, average keratometry, corneal thickness, corneal hysteresis, or corneal resistance factor. The distance-corrected visual acuity was 20/39 preoperatively and 20/36 postoperatively ( P = 0.3). The endothelial cell count decreased by 4.7% ( P < 0.005). These findings suggest that this modified corneal CXL technique is a safe and effective alternative to halt the progression of KC up to five years after the procedure. However, some concerns remain as to whether this technique can affect in some degree the corneal endothelial cells.

Influence of corneal biomechanical properties on IOP indices in patients with keratoconus

The Eye ◽  
2019 ◽  
Vol 21 (128) ◽  
pp. 15-19
Author(s):  
Irina Bubnova ◽  
Veronica Averich ◽  
Elena Belousova
Keyword(s):  
Disease Progression ◽  
Corneal Thickness ◽  
Central Zone ◽  
Biomechanical Properties ◽  
Resistance Factor ◽  
Corneal Resistance Factor ◽  
Mean Values ◽  
Coefficient Of Elasticity ◽  
D Values ◽  
Corneal Biomechanical Properties

Purpose: Evaluation of corneal biomechanical prop¬erties and their influence on IOP indices in patients with keratoconus. Material and methods. The study included 194 eyes with keratoconus (113 patients aged from 23 to 36 years old). Corneal refraction in central zone varied from 48.25 to 56.75 D, values of corneal thickness ranged from 279 to 558 μm. Patients were divided into 4 groups according to Amsler classification: I stage – 40 eyes; II stage – 78 eyes; III stage – 54 eyes and IV stage – 22 eyes. Standard ophthal¬mological examination was carried out including pneumo¬tonometry. IOP indices and values of biomechanical prop¬erties were evaluated by dynamic bidirectional pneumatic applanation and pneumatic impression. Results. Study of corneal biomechanical properties in patients with keratoconus showed a decrease of such biomechanical indices as corneal hysteresis (CH) on aver¬age to 8.42±1.12 mm Hg, corneal resistance factor (CRF) – to 7.45±0.96 mm Hg, coefficient of elasticity (CE) – 5.35± 0.87 mm Hg. Values of these indices strongly depended on the stage of keratoconus. In the whole sample, the aver¬age corneal compensated IOP (IOPcc) amounted to 15.08± 2.43 mm Hg, Goldman IOP (IOPg) was 11.61±2.37 mm Hg and pneumatic tonometry IOP (IOPp) was 10.13±2.94 mm Hg. IOPcc indices didn’t have any statistically significant differ¬ence in dependence on the stage of keratoconus (р>0.473), while in process of disease progression IOPg and IOPp indi¬ces showed statistically significant decrease of mean values. Conclusion. Progression of keratoconus led to a de¬crease in corneal biomechanical properties which deter¬mine reduction of such indices as IOPg and IOPp in contrast to IOPcc.

Impact of hinge motion on stent edge restenosis after new generation drug-eluting-stent implantation in RCA

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
T Jimba ◽  
M Ikutomi ◽  
D Nishijyo ◽  
M Yamasaki ◽  
A Shindou ◽  
...  
Keyword(s):  
Stent Implantation ◽  
Biomechanical Properties ◽  
Plaque Burden ◽  
Drug Eluting Stent ◽  
Landing Zone ◽  
Binary Restenosis ◽  
Drug Eluting ◽  
New Generation ◽  
Hinge Angle

Abstract Background Edge restenosis still occurs after stent implantation, even by using new generation drug-eluting stents (DES) considered to have favorable biomechanical properties. Mechanical stress imposed on the stent edge are thought to be aggravated by hinge motion at a point between the stented and unstented segments, inducing chronic local inflammation and neointimal overgrowth. Purpose The aim of this study was to investigate the association between the development of edge restenosis and hinge motion in right coronary artery (RCA) where the excessive vessel movement is commonly observed. Methods Among consecutive 650 lesions in RCA where new generation DESs were implanted between 2009 and 2019, 427 serial lesions with sets of angiographies at baseline and follow-up (6–18 month) were included. In addition to conventional quantitative angiography analysis, hinge angle at stent edges was measured (Fig. 1). All the appropriate data for intravascular imaging were analyzed for both stent edges and reference segments. Results Binary restenosis occurred in 43 lesions, and 39 of them were referred to re-intervention. Fifty five percent of them were related to stent edges (15 at proximal and 9 at distal edges). Classical risk factors including diabetes and hemodialysis were more prevalent in the restenosis group (p&lt;0.05). Hinge angle was statistically larger in edge restenosis group than body restenosis or no restenosis group (17.3° vs 11.6° vs 10.6°, p&lt;0.001, Fig. 2). In per-edge analysis, hinge angle, dissection and residual plaque ratio were the independent predictors for binary restenosis (Table 1) with the optimal cut-off value of hinge angle 11.5°. The coexistence of excessive hinge angle and residual plaque burden had an amplified effect on the angiographic stenotic progression at stent edge (p for interaction &lt;0.001) and the incidents of binary restenosis (16.7% vs 1.7% p&lt;0.01, Figs. 3,4). Conclusion Substantial stress determined by angulation at the stent edge and its interaction with residual plaque can be considered as one of the plausible mechanisms for edge restenosis. For tortuous RCA lesions, it would be important to decide the stent-landing zone for minimizing hinge motion and optimize the future stent design. Funding Acknowledgement Type of funding source: None

Corneal densitometry in patients with keratoconus undergoing intrastromal Ferrara ring implantation

2021 ◽  
pp. 112067212110206
Author(s):  
Pablo Felipe Rodrigues ◽  
Bernardo Kaplan Moscovici ◽  
Guilherme Ferrara ◽  
Luciano Lamazales ◽  
Marcela Mara Silva Freitas ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Medical Records ◽  
Spherical Equivalent ◽  
Interventional Study ◽  
Data Comparison ◽  
Corneal Densitometry ◽  
Corrected Visual Acuity ◽  
Ring Segment ◽  
The Mean

Objective: Evaluation of central corneal densitometry changes following Ferrara corneal ring segment implantation in patients with keratoconus, especially the correlation between corneal densitometry and keratometry. Methods: Retrospective, non-comparative, interventional study based on the review of medical records of patients diagnosed with keratoconus who underwent Ferrara corneal ring segment implantation. Pre and post-operative corneal densitometry measurements obtained with Pentacam HR (Oculus, Wetzlar, Germany) were analyzed. The follow-up time was 3 months, and data comparison was made, using specific statistical analysis, with the data of 3 months postoperatively. Results: The study sample consisted of 43 eyes of 36 patients. The mean corrected visual acuity improved from 0.82 LogMAR preoperatively (SD ± 0.33) to 0.19 LogMAR (SD ± 0.13) postoperatively. The mean spherical equivalent varied from −4.63 (SD ± 3.94) preoperatively to −2.16 (SD ± 2.63) postoperatively. Asphericity varied from −0.69 (SD ± 0.32) preoperatively to −0.27 (SD ± 0.31) postoperatively. The mean maximum K was 54.01D (SD ± 3.38) preoperatively and 51.50D (SD ± 2.90) postoperatively. The mean anterior densitometric value was 18.26 (SD ± 2.03) preoperatively and 17.66 (SD ± 1.84) postoperatively. Conclusion: Corneal densitometry is an interesting technology that should be studied in keratoconus patients. Our results suggest that the corneal densitometry in the cornea’s anterior layer reduces after ICRS implantation and correlates with corneal keratometry. Further studies should be performed to increase the knowledge in this field.

Regional changes in corneal shape over a 6-month follow-up after femtosecond-assisted LASIK

2019 ◽  
Vol 45 (6) ◽  
pp. 766-777 ◽  
Author(s):  
FangJun Bao ◽  
Si Cao ◽  
JunJie Wang ◽  
Yuan Wang ◽  
Wei Huang ◽  
...  
Keyword(s):  
Corneal Shape

scholarly journals Hydrocephalus presenting as idiopathic aqueductal stenosis with subsequent development of obstructive tumor: report of 2 cases demonstrating the importance of serial imaging

2017 ◽  
Vol 20 (4) ◽  
pp. 329-333 ◽  
Author(s):  
Jarod L. Roland ◽  
Richard L. Price ◽  
Ashwin A. Kamath ◽  
S. Hassan Akbari ◽  
Eric C. Leuthardt ◽  
...  
Keyword(s):  
Late Onset ◽  
Diagnostic Testing ◽  
Subsequent Development ◽  
Mass Effect ◽  
Aqueductal Stenosis ◽  
Pineal Region ◽  
Serial Imaging ◽  
Cerebrospinal Fluid Diversion ◽  
First Case

The authors describe 2 cases of triventricular hydrocephalus initially presenting as aqueductal stenosis that subsequently developed tumors of the pineal and tectal region. The first case resembled late-onset idiopathic aqueductal stenosis on serial imaging. Subsequent imaging revealed a new tumor in the pineal region causing mass effect on the midbrain. The second case presented in a more typical pattern of aqueductal stenosis during infancy. On delayed follow-up imaging, an enlarging tectal mass was discovered. In both cases hydrocephalus was successfully treated by cerebrospinal fluid diversion prior to tumor presentation. The differential diagnoses, diagnostic testing, and treatment course for these unusual cases are discussed. The importance of follow-up MRI in cases of idiopathic aqueductal stenosis is emphasized by these exemplar cases.

scholarly journals Mass Spectrometry but Not Fluorimetry Distinguishes Affected and Pseudodeficiency Patients in Newborn Screening for Pompe Disease

2017 ◽  
Vol 63 (7) ◽  
pp. 1271-1277 ◽  
Author(s):  
Hsuan-Chieh Liao ◽  
Min-Ju Chan ◽  
Chia-Feng Yang ◽  
Chuan-Chi Chiang ◽  
Dau-Ming Niu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Newborn Screening ◽  
Pompe Disease ◽  
Late Onset ◽  
Asian Population ◽  
Dried Blood Spots ◽  
Fluorimetric Assay ◽  
Analytical Range ◽  
Patient Referrals

Abstract BACKGROUND Deficiency of the lysosomal enzyme acid α-glucosidase (GAA) causes Pompe disease. Newborn screening for Pompe disease is ongoing, and improved methods for distinguishing affected patients from those with pseudodeficiency, especially in the Asian population, would substantially reduce the number of patient referrals for clinical follow-up. METHODS We measured the enzymatic activity of GAA in dried blood spots on newborn screening cards (DBS) using a tandem mass spectrometry (MS/MS) assay. The assay displayed a relatively large analytical range compared to the fluorimetric assay with 4-methylumbelliferyl-α-glucoside. DBS from newborns confirmed to have infantile-onset Pompe disease (IOPD, n = 11) or late-onset Pompe disease (LOPD) (n = 12) and those from patients bearing pseudodeficiency alleles with or without Pompe mutations, or Pompe disease carriers (n = 230) were studied. RESULTS With use of the MS/MS GAA assay in DBS, 96% of the pseudodeficiency newborns and all of the Pompe disease carriers were well separated from the IOPD and LOPD newborns. The fluorimetric assay separated &lt;10% of the pseudodeficiencies from the IOPD/LOPD group. CONCLUSIONS The relatively large analytical range MS/MS GAA assay but not the fluorimetric assay in DBS provides a robust approach to reduce the number of referrals and should dramatically facilitate newborn screening of Pompe disease.

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