Application of data mining algorithms to study data trends for corneal transplantation.

PURPOSE: To utilize data mining for analysis of corneal transplantations (CT) in Florida from 2005-2014, segmented by demographics, geography, and transplantation technique. METHODS: A retrospective, database study was performed utilizing data queried from the Healthcare and Cost Utilization Project using Current Procedural Terminology codes for lamellar keratoplasty (ALK), endothelial keratoplasty (EK), and penetrating keratoplasty (PKP). Payer status, ethnic group, age, gender, and geography (urban versus rural) was extracted from each surgical encounter and reconfigured to provide a "clean", congruous dataset for statistical analysis. This Institutional Review Board-approved study did not utilize identifiable patient information; thus, individual informed consent was not required. RESULTS: From 2005-2014, CT (n=28,607) represented less than 1% of the total ambulatory surgeries (n=12,695,932) performed in Florida. EK volume increased while PKP and ALK volume decreased, year-over-year. Statistical significance was found between transplantation technique by sex (P<0.001) and ethnic group (P<0.001). The largest sex discrepancy was EK (59% female, 41% male). White patients underwent relatively fewer PKP than EK (71% vs. 83% of totals), while Black patients underwent relatively more PKP than EK (14% vs 6% of totals). Statistical significance was found between techniques by payer (P<0.001). Medicare was the most common payer for all techniques, but ALK and PKP had higher percentages of private insurance and self-pay. No statistical significance was found between techniques by geographic location. Corneal edema (22.4%), endothelial dystrophy (17.5%), and bullous keratopathy (10.9%) were erroneously coded as indications for ALK. Corneal scars (2.5%) and corneal opacity (1.7%) were erroneously coded as indications for EK. CONCLUSIONS: CT rates in Florida appear to overrepresent the female sex and underrepresent ethnic minorities, with propensities between PKP and African Americans, EK and female patients, and EK and Medicare reimbursement. Our study further confirms the utility of data mining for providing efficient, detailed, and practical insights into ophthalmology procedures, while highlighting the intrinsic challenges of large datasets.

Risk Factors for Repeat Keratoplasty After Endothelial Keratoplasty-An IRIS Registry Analysis.

PURPOSE: To assess risk factors for repeat keratoplasty after endothelial keratoplasty (EK). DESIGN: Retrospective cohort study. METHODS: EK procedures performed between 2013 and 2018 in the IRIS Registry (Intelligent Research in Sight) were identified. STUDY POPULATION: Patients aged 18 years and older who underwent EK. MAIN OUTCOME MEASURES: (1) Risk factors for repeat keratoplasty and (2) complication rates after EK. A Kaplan-Meier survival analysis was used to determine the probability of repeat keratoplasty. A multivariable shared frailty survival model was used to assess risk factors. RESULTS: A total of 59 344 procedures were identified in the registry, of which 30 600 EK procedures met the inclusion criteria for the analysis. The probability of repeat keratoplasty was 17.4% (95% CI 16.7-18.0) at 5 years. Risk factors for repeat keratoplasty include postoperative rebubbling procedure (HR 2.24, 95% CI 2.05-2.45), prior failed graft (HR 2.07, 95% CI 1.84-2.32) or bullous keratopathy (HR 1.47, 95% CI 1.33-1.61) vs Fuchs dystrophy as surgical indication; subsequent routine cataract surgery (HR 1.61, 95% CI 1.45-1.79), as well as subsequent (HR 1.53, 95% CI 1.39-1.69) and prior/concurrent (HR 1.23, 95% CI 1.11-1.36) glaucoma surgery or history of glaucoma (HR 1.24, 95% CI 1.14-1.35). Medicaid (HR 1.47, 95% CI 1.13-1.92), military/government (HR 1.29, 95% CI 1.03-1.60), Medicare Fee-for-Service (HR 1.17, 95% CI 1.05-1.31) or Medicare Managed (HR 1.17, 95% CI 1.01-1.36) insurances vs private insurance, as well as Black vs White race (HR 1.25, 95% CI 1.11-1.40) and smoking (HR 1.16, 95% CI 1.05-1.27) were also associated with an increased risk of undergoing repeat keratoplasty. CONCLUSIONS: Black race, government-based insurance plans, and smoking were identified as independent factors associated with repeat keratoplasty in addition to history of glaucoma, glaucoma surgery, and prior graft failure or bullous keratopathy as surgical indication.

Assessment of Corneal Densitometry in Big-Bubble Dissection Versus Manual Dissection Deep Anterior Lamellar Keratoplasty.

PURPOSE: The aim of this study was to assess corneal densitometry and visual outcomes after big-bubble deep anterior lamellar keratoplasty (BB-DALK) and manual dissection deep anterior lamellar keratoplasty in patients with keratoconus. METHODS: This retrospective comparative observational study included 40 keratoconic patients who underwent DALK surgery: 22 eyes had BB-DALK (group I) and 18 eyes had failed BB technique and DALK was completed by manual dissection (group II). Best -corrected visual acuity (BCVA), corneal topographic parameters, residual stromal tissue thickness, and endothelial cell count were recorded at 1, 3, 6, and 12 months postoperatively. Densitometric analysis of different corneal layers and zones was performed using Scheimpflug tomography at each visit; values were recorded and compared between the 2 groups. RESULTS: At 1 and 6 months postoperatively, BCVA was better in group I than in group II, but with no statistically significant difference. At 12 months, the visual acuities became nearly similar in both groups (0.30 ± 0.13 vs. 0.30 ± 0.14 logarithm of the minimum angle of resolution, P = 0.888). Regarding corneal densitometric analysis, the recorded values for the posterior corneal layer were significantly higher in group II compared with group I at 3, 6, 9, and 12 months postoperatively in the 0- to 2-mm zone (P < 0.001) and the 2- to 6-mm zone (P = 0.029, 0.028, 0.001, and <0.001). CONCLUSIONS: Manual dissection DALK after failed BB technique may affect the interface stromal reflectivity up to 12 months postoperatively. However, this does not significantly affect the visual acuity in comparison with successful BB-DALK.

Corneal biomechanics and intraocular pressure assessment after penetrating keratoplasty for non keratoconic patients, long term results.

BACKGROUND: To evaluate corneal biomechanical properties by the Ocular Response Analyzer (ORA) in non keratoconic patients underwent penetrating keratoplasty (PK). METHODS: Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann- correlated intraocular pressure (IOPg), cornea-compensated IOP (IOPcc) using the ORA, and central graft thickness (CGT) were measured in 30 eyes at least two years after penetrating keratoplasty for non keratoconic indications. IOP using the Goldmann applanation tonometer (GAT) was also obtained after compensation for graft thickness and astigmatism. RESULTS: The mean age of patients was 33.1 ± 10.13 years; indications for PK were herpetic corneal scar (53.3%), corneal stromal dystrophy (23.3%), traumatic corneal opacity (10%), chemical corneal opacity (6.7%), and Fuchs endothelial dystrophy (6.7%). Mean CH and CRF were 8.52 ± 1.81 mmHg, and 8.56 ± 1.59 mmHg, respectively. Mean CGT was 532.43 ± 30 µm. Mean IOP GAT, IOPg, and IOPcc were 11.88 ± 3.66, 14.64 ± 4.08, and 17.27 ± 4.60 mmHg, respectively (P < 0.001). No significant association was found between CGT and IOP readings obtained using either the ORA or GAT. There were significant negative association between CH with both IOP GAT and IOPcc, while CRF had significant positive association with IOPg. CONCLUSION: After penetrating keratoplasty for non keratoconic patients, graft biomechanics does not return to average values even 2 years after the operation; moreover, intraocular pressure measurement with ORA gives higher values than thickness compensated GAT.

[Practical assessment of DSAEK in the management of endothelial decompensation following penetrating keratoplasty]. / Évaluation pratique de la prise en charge par DSAEK des décompensations endothéliales après kératoplasties transfixiantes.

PURPOSE: To report our anatomical and functional results as well as possible complications of the first six Descemet's stripping endothelial keratoplasties (DSAEK) performed in our department for endothelial decompensation after penetrating keratoplasty (PK) METHODS: This was a retrospective and observational monocentric study of six patients with DSAEK after prior PK between January 2015 and July 2016. The data collected were: demographic characteristics (age, sex), ophthalmological comorbidities, initial indication for PK, delay between PK and DSAEK. Best corrected visual acuity (BCVA) preoperatively and at 1, 3 and 6 months postoperatively were collected in Monoyer's and Parinaud scale and converted to log MAR for statistical analysis. The central cornea and graft thickness measured on OCT as well as postoperative complications were also collected. RESULTS: Mean follow-up duration was 7.2 months [3-10]. The average time after PK was 7.7 years. The mean age of the patients was 67.5 years [32-87]. The initial indication for PK was Fuchs dystrophy (3/6), pseudophakic bullous keratopathy (1/6), corneal laceration (1/6) and other corneal dystrophy (1/6). The authors report one case a combined phaco-DSAEK surgery. The complications observed were: an early graft detachment treated by an additional air bubble injection (1/6) and cystoid macular edema in one other case. The average central corneal thickness decreased from 780µm at day 7 postoperatively to 656µm at 6 months. The average thickness of the graft decreased from 154µm at day 7 to 122µm at 6 months. The mean preoperative BCVA was 1.52 log MAR [1.0-1.7], compared to the mean postoperative BCVA which was 1.5 log MAR [1.1-2.3] at 1 month, 1.15 log MAR [0.5-1.7] at 3 months and 1.1 log MAR [0.7-1.7] at 6 months (data available for 4 patients at 6 months). The recovery of visual acuity was limited in 2 cases, despite corneal clarity restored in all our patients. DISCUSSION: Our results can be compared to those described in literature. As more penetrating keratoplasty grafts reach the end of their lives, this will allow for more powerful studies. CONCLUSION: DSAEK on eyes previously treated with PK is a good alternative to a new PK in the case of endothelial decompensation of the graft. The possibility of a posterior lamellar graft allows for faster visual recovery, with preservation of the anterior corneal power and a lower rate of complications.

[Comparison of anatomic and functional results between Z6 femtosecond laser assisted and manual trephination in deep anterior lamellar keratoplasty for advanced keratoconus [French version]]. / Comparaison des résultats anatomiques et fonctionnels à 12 mois d'une série de kératoplasties lamellaires profondes assistées au laser femtoseconde Z6 versus trépanation manuelle pour kératocônes sévères.

The management of severe keratoconus requires corneal transplantation, for which the gold standard is deep anterior lamellar keratoplasty (DALK), preserving the healthy Descemet's membrane and endothelium. The safety and reproducibility of corneal cuts have been improved by the evolution of femtosecond lasers in refractive surgery, and femtosecond laser in DALK would seem to provide the same advantages over the manual method. In our retrospective study, we compare functional and anatomical results of femtosecond assisted DALK versus manual trephination DALK in patients with keratoconus in stage 4 of the Krumeich classification. It is a retrospective study including all patients with stage 4 keratoconus who underwent femtosecond laser assisted DALK between November 2012 and November 2015 in Nantes hospital. We compared those patients to a group of patients who underwent manual DALK in the same period, paired by age and maximal keratometry. We assessed visual acuity, pachymetry, endothelial cell density (specular microscopy), and keratometry before surgery and at 4, 8 and 12 months of follow-up. Laser settings and intraoperative complications were recorded. Nineteen patients underwent surgery by femtosecond assisted DALK, 6 women and 12 men with average age 30.2±10.8 years at transplantation. They were paired with a group of 17 patients who underwent manual DALK in order to compare results. Before surgery, mean visual acuity in the femtosecond group was 0.90 logMAR versus 0.89 logMAR in the manual group, showing no statistically significant difference (P=0.96). Both groups were similar in terms of preoperative age, mean keratometry, pachymetry and endothelial cell density. Average visual acuity post-surgery was 0.27, 0.26; and 0.14 logMAR for femtosecond DALK versus 0.27, 0.17 et 0.25 for manual DALK at 4, 8 and 12 months follow-up, respectively showing no statistically significant difference. After surgery, at 4, 8 and 12 months, mean pachymetry was similar in both groups, and average endothelial cell density was 2390 cells/mm2 in femtoDALK versus 2531 cells/mm2 in manual DALK at 12 months of follow-up, showing no statistically significant difference (P=0.5726). The rate of Descemet's membrane microperforations during the procedure was low and similar for both groups. Our study allows for a 12 month follow-up, with assessment of visual recovery, anatomical result and endothelial safety in a sample of 19 femtosecond laser assisted DALK with no statistical significant difference versus the manual trephination group. Femtosecond laser allows for increased reproducibility of the DALK procedure without reducing adverse effects during surgery. Femtosecond laser seems to improve the technique of the DALK procedure, and future developments could improve the reproducibility of DALK even further. A medical economics study would be necessary to determine the cost effectiveness of femtosecond laser assisted DALK.

Comparison of 12-month anatomic and functional results between Z6 femtosecond laser-assisted and manual trephination in deep anterior lamellar keratoplasty for advanced keratoconus.

The management of severe keratoconus requires corneal transplantation, for which the gold standard is deep anterior lamellar keratoplasty (DALK), preserving the healthy Descemet's membrane and endothelium. The safety and reproducibility of corneal cuts have been improved by the evolution of femtosecond lasers in refractive surgery, and femtosecond laser in DALK would seem to provide the same advantages over the manual method. In our retrospective study, we compare functional and anatomical results of femtosecond-assisted DALK versus manual trephination DALK in patients with keratoconus in stage 4 of the Krumeich classification. It is a retrospective study including all patients with stage 4 keratoconus who underwent femtosecond laser-assisted DALK between November 2012 and November 2015 in Nantes university medical center. We compared those patients to a group of patients who underwent manual DALK in the same period, paired by age and maximal keratometry. We assessed visual acuity, pachymetry, endothelial cell density (specular microscopy), and keratometry before surgery and at 4, 8 and 12 months of follow-up. Laser settings and intraoperative complications were recorded. Nineteen patients underwent surgery by femtosecond-assisted DALK, 6 women and 12 men with average age 30.2±10.8 years at transplantation. They were paired with a group of 17 patients who underwent manual DALK in order to compare results. Before surgery, mean visual acuity in the femtosecond group was 0.90 logMAR versus 0.89 logMAR in the manual group, showing no statistically significant difference (P=0.96). Both groups were similar in terms of preoperative age, mean keratometry, pachymetry and endothelial cell density. Average visual acuity post-surgery was 0.27; 0.26; and 0.14 logMAR for femtosecond DALK versus 0.27; 0.17 et 0.25 for manual DALK at 4, 8 and 12 months follow-up respectively, showing no statistically significant difference. After surgery, at 4, 8 and 12 months, mean pachymetry was similar in both groups, and average endothelial cell density was 2390 cells/mm2 for femto DALK versus 2531 cells/mm2 for manual DALK at 12 months of follow-up, showing no statistically significant difference (P=0.5726). The rate of Descemet's membrane microperforations during the procedure was low and similar for both groups. Our study allows for a 12-month follow-up, with assessment of visual recovery, anatomic result and endothelial safety in a series of 19 femtosecond laser-assisted DALK with no statistical significant difference versus the manual trephination group. Femtosecond laser allows for increased reproducibility of the DALK procedure without reducing adverse effects during surgery. Femtosecond laser seems to improve the technique of the DALK procedure, and future developments could improve the reproducibility of DALK even further. A medical economics study would be necessary to determine the cost-effectiveness of femtosecond laser-assisted DALK.

[Objective assessment of donor material for penetrating corneal transplantation]. / Ob''ektivizatsiia otsenki donorskogo materiala dlia skvoznoi peresadki rogovitsy.

Reliable suitability evaluation of donor material is the crucial issue of penetrating corneal transplantation. The main parameter to be considered is endothelial cell density (ECD). However, when it comes to practice, one has to admit significant variation in ECD readings of cadaver corneas obtained by different methods. AIM: to investigate discrepancies in ECD measurements and to define objective criteria for the evaluation of a donor cornea before full-thickness grafting. MATERIAL AND METHODS: In a hundred cadaver eyes, discrepancies in ECD measurements by different methods (specular microscopy, confocal microscopy, and keratoanalyzer) were studied and objective evaluation criteria developed along with an optimal algorithm of pretransplantation assessment. Digital fluorescence microscopy was chosen as the reference method. RESULTS: It has been established that a triple measurement average obtained with any of the tested methods is informative enough as to the state of the donor cornea. CONCLUSION: The highest ECD values were obtained with specular microscopy, the lowest - with confocal microscopy. For reliable evaluation of donor corneas, we recommend that the average of a triple ECD measurement be taken using one of the mentioned methods.

Quantitative assessment of videokeratography data using fourier series harmonic analysis.

PURPOSE: To describe a method of mathematically decomposing videokeratography data using Fourier series harmonic analysis and present examples of its clinical application. METHODS: Videokeratography data were decomposed by Fourier analysis into spherical component, regular astigmatism, asymmetry (decentration or skewness), and higher-order irregular astigmatism. These 4 Fourier components were analyzed in both normal and pathologic eyes. Color-coded maps were generated to present the 4 Fourier components. RESULTS: Color-coded mapping of the results of Fourier analysis of videokeratography data facilitated visual and instant interpretation of complex corneal topographic information. By using Fourier components, time course of changes in corneal topography following penetrating keratoplasty and influence of suture removal were quantitatively evaluated. The Fourier analysis method was successfully applied to determine the most appropriate correction lenses in eyes after penetrating keratoplasty. CONCLUSIONS: Fourier analysis of videokeratography data allows mathematical separation of regular and irregular astigmatism and is useful in the quantitative assessment of corneal optics in eyes with both pathologic and postsurgical conditions.

Price graft-over-host technique to manage positive pressure during penetrating keratoplasty.

Intraoperative positive pressure with resulting iris and lens prolapse can pose a difficult scenario during penetrating keratoplasty. In the Price graft-over-host technique, the graft is sutured across the trephinated host cornea, which maintains a formed anterior chamber and thus avoids intraoperative complications. The technique was used in 33 eyes, and no primary or secondary graft failures occurred. Eleven episodes of acute rejection in 11 eyes were treated successfully with steroids.