Impact of Surgical Learning Curve in Descemet Membrane Endothelial Keratoplasty on Visual Acuity Gain.

PURPOSE: To evaluate the learning curve for graft preparation and graft unrolling during Descemet membrane endothelial keratoplasty (DMEK) and to assess the evolution of visual acuity gain and percentage cell loss with experience. METHODS: The first 109 DMEK procedures performed by a single surgeon (A.S.) at the Rothschild Foundation Ophthalmology Hospital in Paris, France, between March 2012 and November 2014 were included. Best-corrected visual acuity and endothelial cell density were recorded preoperatively and again 1 week, 1 month, 3 months, and 6 months after DMEK. Donor age and ECC were registered. Graft preparation time and graft unrolling time were assessed using video recording. Incidence and types of complications were noted. RESULTS: The number of cases necessary to reach 90% of the plateau of the learning curve was 68 for preparation time and 46 for unrolling time in this model. There was no correlation between the best-corrected visual acuity gain at 6 months postsurgery and the learning curve. The percentage cell loss was found to be significantly lower with experience (R = 0.17, P = 0.0011). CONCLUSIONS: Surgical experience allowed faster graft preparation and faster unrolling time in DMEK. Neither experience nor percentage cell loss influenced postoperative visual acuity gain. The number of procedures needed to reach a good standard of care was estimated to be 50 in our patient database.

Changes to Corneal Aberrations and Vision After Monovision in Patients With Hyperopia After Using a Customized Aspheric Ablation Profile to Increase Corneal Asphericity (Q-factor).

PURPOSE: To evaluate the visual outcomes and fourth-order Zernike spherical aberrations induced with a customized change in corneal asphericity (ΔQ) correction of presbyopia combined with monovision for hyperopic patients. METHODS: Consecutive hyperopic patients who underwent presbyopic LASIK between September 2013 and July 2014 were included. For the non-dominant eyes, the aspheric ablation profile associated with a myopic refraction was planned using the Custom-Q nomogram (Alcon Laboratories, Inc., Fort Worth, TX). Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), spherical equivalent refraction, ΔQ, and change in corneal spherical aberration coefficient (ΔC40) were analyzed. Postoperative data were collected at 1, 3, and 6 months. RESULTS: Sixty-five patients were included. The mean age was 56.5 ± 5.7 years (range: 47 to 70 years). At the 6-month follow-up, the spherical equivalent refraction for non-dominant and dominant eyes was -1.07 ± 0.74 and 0.32 ± 0.55 diopters (D), respectively. The mean binocular UDVA was 0.01 ± 0.04 logMAR (range: -0.12 to 0.30 logMAR); 91% of patients achieved 20/20 or better binocular UDVA and 83% of patients had Jaeger 3 (Parinaud 4) or better binocular UNVA. The ΔQ for non-dominant and dominant eyes was -0.61 ± 0.15 and -0.33 ± 0.25, respectively, for a 6-mm pupil diameter and was significantly higher for non-dominant eyes (P < .0001). The achieved ΔC40 was -0.49 ± 0.23 µm for non-dominant eyes (for a theoretical ideal value of -0.40 µm) and -0.30 ± 0.18 µm for dominant eyes. For non-dominant eyes, the attempted ΔQ (-0.60) was close to the achieved value (-0.61 ± 0.15). CONCLUSIONS: For hyperopic patients, combining the customized corneal aspheric ablation profile with monovision is safe, effective, and reproducible, inducing intended changes in corneal spherical aberrations. [J Refract Surg. 2016;32(11):734-741.].

Visual Recovery and Clinical Outcomes With Torn Donor Tissue: A Comparative Study on Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To evaluate the clinical impact of implanting donor tissue torn during preparation for the Descemet membrane endothelial keratoplasty procedure. METHODS: In this single-center retrospective analysis of consecutive cases, 10 cases with torn donor tissue from one surgeon's caseload of 175 procedures were analyzed and compared with control cases. Best-corrected visual acuity, endothelial cell density of the donor tissue measured by specular microscopy, and the recipient's central corneal thickness were recorded preoperatively and again 1, 3, and 6 months after surgery. RESULTS: In the torn graft group, mean central corneal thickness decreased from 660 ± 81 µm preoperatively to 520 ± 36 µm at 6 months after surgery. central corneal thickness was higher at 1 month but decreased faster between 1 and 3 months in the torn graft group compared with the controls (-86 ± 50.2 µm and -12.6 ± 25.5 µm, respectively, P = 0.04). Best-corrected visual acuity in the torn graft group was 0.25 ± 0.23 logMAR, 0.21 ± 0.20 logMAR, and 0.16 ± 0.16, respectively, at 1, 3, and 6 months after surgery with no significant differences found when compared with controls. The percent endothelial cell loss between the preoperative and 1-month postoperative values was significantly higher in the torn graft group than in the controls (32.3% and 24.6%, respectively, P = 0.04) but was identical at 6 months (35.7% in the torn graft group and 34.8% in the control group). CONCLUSIONS: Anatomical recovery was shown to be slower in patients who received torn donor tissue, but long-term clinical outcomes were similar in both groups.

Repeatability of Keratometry Measurements Obtained With Three Topographers in Keratoconic and Normal Corneas.

PURPOSE: To assess the repeatability of the corneal topography functions of Orbscan II (Bausch & Lomb, Rochester, NY), OPD-Scan III (Nidek, Gamagori, Japan), and iTrace (Tracey Technologies, Houston, TX) in keratoconic eyes and in a control group of normal patients. METHODS: In this prospective cohort study, patients were recruited between November 2011 and May 2012. Measurements were performed with a combined Placido-scanning slit system (Orbscan II) and two combined Placido-aberrometer systems (OPD-Scan III and iTrace). Repeatability limit and intraclass correlation coefficients (ICCs) of keratometric readings were calculated. RESULTS: Fifty-nine keratoconic eyes of 34 patients and 54 normal eyes of 27 patients were included. Three groups were evaluated: all stage I-IV keratoconic eyes (59 eyes), a subgroup consisting of stage I-II keratoconic eyes (41 eyes), and normal eyes (54 eyes). For almost all parameters studied, the repeatability limit was higher in the two groups of keratoconic eyes compared to normal eyes with all three topographers, indicating lower repeatability. For the maximum keratometry measurement, repeatability limit was 1.73, 1.49, and 1.41 diopters (D) in the stage I-IV keratoconic eyes group, 1.11, 1.02, and 0.98 D in the stage I-II keratoconic eyes group, and 0.61, 0.37, and 1.02 D in the normal eyes group with Orbscan II, OPD-Scan III, and iTrace, respectively. CONCLUSIONS: Topographies performed in keratoconic eyes are less repeatable than those performed in normal eyes. Threshold values of keratometric changes used to ascertain keratoconus progression should be carefully considered. Caution should be taken when interpreting the topographies of such patients. The higher variability should be taken into account before performing any treatment.

Opaque Bubble Layer Risk Factors in Femtosecond Laser-assisted LASIK.

PURPOSE: To determine the characteristics and risk factors for occurrence of opaque bubble layer (OBL) during femtosecond laser-assisted flap creation for LASIK. METHODS: One hundred ninety-eight eyes of 102 consecutive patients who underwent LASIK flap creation performed with the Alcon WaveLight FS200 laser (Alcon Laboratories, Inc., Fort Worth, TX) were retrospectively analyzed in a cohort study. Preoperative manifest refraction, corneal keratometry, central corneal thickness, white-to-white corneal diameter, corneal hysteresis, corneal resistance factor, and programmed flaps parameters were collected. Digital images automatically recorded after flap creation were analyzed to measure OBL areas. Correlation tests were performed between preoperative corneal parameters and OBL areas. RESULTS: The incidence rate of OBL was 48% (103 eyes). The mean OBL area as a percentage of the corneal flap area in the OBL group was 4.25% ± 7.16% (range: 0% to 32.9%). The central corneal thickness, corneal resistance factor, and corneal hysteresis were significantly positively correlated with the OBL area (r = 0.242, P = .001; r = 0.254, P = .028; and r = 0.351, P < .0001, respectively). Corneal hysteresis and OBL area were positively correlated, independently of the central corneal thickness and other confounder factors with standardized coefficient (r = 0.353 ± 0.227, P = .002). CONCLUSIONS: This study confirms the already known OBL risk factors with a larger cohort and suggests for the first time that an elevated corneal hysteresis is an independent predictive risk for OBL occurrence.

Simultaneous Correction of Unilateral Rainbow Glare and Residual Astigmatism by Undersurface Flap Photoablation After Femtosecond Laser-Assisted LASIK.

PURPOSE: To report and document a case of successful rainbow glare correction using undersurface ablation of the LASIK flap. METHODS: A 33-year-old woman was treated bilaterally for myopia using femtosecond laser-assisted LASIK with the FS200 femtosecond laser (Alcon Laboratories, Inc., Fort Worth, TX). Postoperatively, she complained of rainbow glare in her right eye, and presented some residual myopic astigmatism. Six months after the initial LASIK procedure, the right eye flap was lifted and a toric excimer correction was delivered on its stromal side. RESULTS: Visual symptoms related to the rainbow glare disappeared immediately after the completion of the procedure and did not reoccur. Uncorrected visual acuity improved by two lines. CONCLUSIONS: Rainbow glare following femtosecond laser-assisted LASIK can be successfully corrected by undersurface ablation of the flap.

Intraoperative OCT-Assisted DMEK: 14 Consecutive Cases.

PURPOSE: To describe the utility of a new intraoperative optical coherence tomographer (OCT) to evaluate endothelio-Descemet graft orientation during Descemet membrane endothelial keratoplasty (DMEK) procedures. METHODS: Prospective, observational, and single-center pilot case series including 14 eyes of 14 patients consecutively scheduled for DMEK surgery. After injecting the graft into the anterior chamber, the graft orientation was assessed with the help of anterior segment OCT. The surgical time and unfolding time were measured. The postoperative measurements included best-corrected visual acuity, central pachymetry, and specular microscopy at 1 month. RESULTS: Using the OCT images, it was possible to evaluate the graft orientation in all cases. The mean unfolding time was 6.1 ± 3.0 minutes, the mean best-corrected visual acuity was 0.3 ± 0.3 logarithm of the minimum angle of resolution, the mean decrease in central pachymetry was 213 ± 177 µm, and the mean central endothelial cell count was 1906 ± 319 cells per square millimeter. CONCLUSIONS: Live intraoperative OCT is useful to visualize and assess graft orientation in DMEK surgery. It enables faster graft positioning with less graft manipulation in the presence of severe corneal edema.

Corneal enantiomorphism in normal and keratoconic eyes.

PURPOSE: To evaluate the ability to discriminate between normal and keratoconic corneas by analyzing intereye corneal asymmetry parameters and defining a score of similarity that outlines the normal range of asymmetry between right and left eyes. METHODS: This prospective, non-randomized study included 102 normal corneas of 51 patients and 64 keratoconic corneas of 32 patients. Topographic and tomographic parameters of the right and left eyes were extracted from an elevation and Placido-based corneal topography. Asymmetry was determined by subtracting the right eye value from the left eye value for each variable and by considering the absolute value of the result. A discriminant function was constructed to separate the normal and keratoconic groups. RESULTS: The mean intereye asymmetry differences were statistically significant for all variables except the vertical and horizontal decentration of the thinnest point, the corneal thickness at 2.5, 3, 3.5, and 4 mm from the thinnest point, and the posterior keratometry at 4.5 mm from the thinnest point. The discriminant function was composed of three variables (the difference between flat and steep keratometry, the 3-mm irregularity, and the anterior elevation of the thinnest point) and reached an area under the receiver operator characteristic curve of 0.992, a sensitivity of 94%, and a specificity of 100%. CONCLUSIONS: A discriminant function constructed from the intereye difference of three corneal indices may be accurate and useful for the topography-based detection of advanced keratoconus. In the future, incorporating such data in automated artificial intelligence software may improve the detection ability of earlier forms of keratoconus.

Measurement of pupil center shift in refractive surgery candidates with caucasian eyes using infrared pupillometry.

PURPOSE: To evaluate the effectiveness of the pupil center shift with changes in the state of pupil size and with other ocular variables. METHODS: Dynamic pupillometry with the Topolyzer Vario (Alcon Laboratories, Inc., Fort Worth, TX) was performed in 248 eyes of 124 patients scheduled for corneal laser refractive surgery. High-resolution images were obtained using the infrared-sensitive camera (incorporated in the videokeratoscope) under mesopic and photopic conditions. Measurements of pupil diameters, distance between the pupil center and keratoscopic axis, and spatial shift of the pupil center were obtained after analysis. RESULTS: The mean distance between the pupil center and the corneal vertex in mesopic and photopic conditions of illumination in myopic eyes was 0.27 ± 0.14 (range: 0.02 to 0.70 mm) and 0.24 ± 0.12 mm (range: 0.06 to 0.65 mm), respectively, whereas it was 0.36 ± 0.15 (range: 0.03 to 0.70 mm) and 0.31 ± 0.16 mm (range: 0.03 to 0.77 mm) in hyperopic eyes, respectively. The mean spatial pupil center shift was significant: 0.11 ± 0.07 mm (range: 0.02 to 0.57 mm) in myopic eyes and 0.12 ± 0.09 mm (range: 0.02 to 0.47 mm) in hyperopic eyes. The pupil center shifted consistently temporally as the pupil dilated. The pupil center shift was not significantly related to sex, age, eye (right or left), or refractive error. CONCLUSIONS: The mean distance between the pupil center and the corneal vertex is greater in hyperopic eyes than in myopic eyes, whereas the spatial shift of this pupil center has a temporal direction as the pupil dilates and is constantly small in all groups. However, pupil center shift can be important in a few patients.

AcuTarget measurements: repeatability and comparison to OPD-Scan III.

PURPOSE: To evaluate repeatability of the AcuTarget (SensoMotoric Instruments, Teltow, Germany) measurements and compare them to those obtained with the OPD-Scan III (NIDEK, Inc., Fremont, CA). METHODS: Measurements were taken with the AcuTarget and OPD-Scan III in 62 eyes of 31 patients. Results were compared using paired Student's t tests, Pearson correlation coefficients, and 95% limits of agreement. RESULTS: Repeatability of the AcuTarget was good with intraclass correlation coefficients of 0.773, 0.777, and 0.780 for Purkinje-versus-pupil along the x-axis, y-axis, and chord length measurements, respectively. No statistically significant difference was observed between the AcuTarget and OPD-Scan III for Purkinje-versus-pupil measurement along the x-axis (P = .061) and chord length (P = .950). Conversely, a statistically significant difference was observed between the two systems for measurements along the y-axis (P < .001). No statistical difference was found between the mean of the first three acquisitions and the best acquisition obtained with the AcuTarget. CONCLUSIONS: Measurements provided by the AcuTarget have good repeatability and are close to those obtained with the OPD-Scan III. Although controversies remain on where to best center refractive procedures, this may help in analyzing the importance of refractive surgery centration in relation to visual acuity and visual symptoms.

Repeatability of Ocular Response Analyzer waveform parameters in normal eyes and eyes after refractive surgery.

PURPOSE: To study the repeatability of the biomechanical waveform parameters measured with the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Depew, NY) device in normal eyes and eyes after refractive surgery. METHODS: This was a prospective, comparative non-interventional study of a case series. Two hundred eyes of 100 patients were divided into five groups: normal eyes of patients younger than 30 years, normal eyes of patients between 30 and 50 years old, normal eyes of patients older than 50 years, eyes of patients with a history of LASIK, and eyes of patients with a history of photorefractive keratectomy. The repeatability of the 37 waveform parameters in addition to corneal hysteresis (CH), corneal resistance factor (CRF), IOP measurement with Goldmann applanation tonometer (IOPg), and IOP evaluated with the intraclass correlation coefficient (ICC) (IOPcc) were examined. RESULTS: In addition to IOPg, IOPcc, CRF, and CH, five parameters had an ICC greater than 0.6 (substantial agreement): P1area, the area of peak 1 (ICC = 0.823); P2area, the area of peak 2 (ICC = 0.646); h1, the height of peak 1 (ICC= 0.702); P1area1, the area of peak 1 derived from the upper 50% of the applanation peak (ICC = 0.772); and h11, the height of peak1 derived from the upper 50% of the applanation peak 1 (ICC = 0.697). CONCLUSIONS: This study shows that not all parameters derived from the corneal deformation waveform signal have the same repeatability. Therefore, analysis of the waveform indices should rely on the more repeatable ones to derive consistent conclusions.

Unilateral rainbow glare after uncomplicated femto-LASIK using the FS-200 femtosecond laser.

PURPOSE: To report a case of rainbow glare following femtosecond laser-assisted LASIK (femto-LASIK) with the Wavelight FS-200 femtosecond laser (Alcon Laboratories, Inc., Fort Worth, TX). METHODS: A patient was treated bilaterally for myopia with femto-LASIK using the FS-200 femtosecond laser. Postoperatively, he complained of rainbow glare in his right eye. RESULTS: Three months postoperatively, the induced grating pattern (hyperreflective spot-like zones corresponding to the surgeon-programmed spot and line separation distance of the FS-200 femtosecond laser) was demonstrated with confocal microscopy at the level of the flap interface in the right eye. CONCLUSIONS: This is the first report of rainbow glare following femto-LASIK with the FS-200 femtosecond laser documented with in vivo confocal microscopy.

Unilateral ectasia after LASIK in a patient with abnormal topography but normal tomography.

PURPOSE: To report a case of unilateral ectasia developing after LASIK in a patient with abnormal topography but normal tomographic indices. METHODS: Case report and literature review. RESULTS: A patient was treated bilaterally for myopia using LASIK. Five years and 5 months postoperatively, unilateral ectasia in the right eye was diagnosed. Preoperatively, anterior curvature (Placido) map of the right cornea showed an asymmetry with 1.8 diopters of steepening when evaluated from upper left to lower right meridians, and a skewing of the steepest radial axes. The calculated KISA% index was 128.4 in the right eye and 5.6 in the left eye. Conversely, posterior elevation map and pachymetry map of the right eye showed no frank abnormalities. CONCLUSIONS: This case is interesting because it shows that for this patient, the anterior curvature (Placido) map was more sensitive to detect cornea at risk of post-LASIK ectasia than the tomographic features

Long-term rejection incidence and reversibility after penetrating and lamellar keratoplasty.

PURPOSE: To identify risk factors for corneal graft rejection and rejection irreversibility. DESIGN: Retrospective cohort study. METHODS: setting: Institutional. patients: A total of 1438 consecutive eyes of 1438 patients who underwent corneal transplantation for optical indication at the Centre Hospitalier National d'Ophtalmologie des XV-XX, Paris, France, between December 1992 and December 2010 were studied. Surgical technique was penetrating keratoplasty (PK) in 1209 cases, anterior lamellar keratoplasty (ALK) in 165 cases, and Descemet stripping with endothelial keratoplasty in 64 cases. main outcome measures: Cumulative incidence of rejection episodes and rejection irreversibility rate. RESULTS: A total of 299 cases of rejection episodes were identified, of which 145 (48.5%) were irreversible after treatment. In multivariate analysis, the cumulative incidence of rejection episodes was influenced by recipient age (P = .00002), recipient rejection risk (P = .0003), lens status (P = .00003), and surgical group (P = .035). A higher incidence of rejection episodes was observed in young patients (<20 years) and patients aged from 41 to 50, high-risk recipients, aphakic eyes and eyes with anterior chamber intraocular lens, and eyes with PK (compared with eyes with ALK). Rejection episodes were more likely to be irreversible for high-risk recipients (P = .02), for eyes with preoperative hypertony (P = .009), and for eyes with poor visual acuity at presentation (P = .002). CONCLUSIONS: Recipient rejection risk and surgical group are the main risk factors for rejection as they both influence the incidence of rejection and the reversibility rate. Recipient age and lens status are predictive factors for the occurrence of rejection. Preoperative hypertony is a predictive factor for rejection irreversibility.

Corneal thickness, curvature, and elevation readings in normal corneas: combined Placido-Scheimpflug system versus combined Placido-scanning-slit system.

PURPOSE: To evaluate agreement in central corneal thickness (CCT), keratometry, and anterior and posterior elevation map measurements in normal corneas between a combined Placido-Scheimpflug system and a combined Placido-scanning-slit elevation topography system. SETTING: Department of Cataract & Refractive Surgery, Rothschild Foundation, Paris, France. DESIGN: Evaluation of diagnostic test or technology. METHODS: Measurements were performed with a combined Placido-Scheimpflug system (TMS-5) and a combined Placido-scanning-slit system (Orbscan II). Ultrasound (US) pachymetry was used as the reference for CCT measurements. Bland-Altman plots were used to evaluate agreement between instruments. RESULTS: The mean CCT measurements by US pachymetry, the Placido-Scheimpflug system, and the Placido-scanning-slit system were 556.74 µm ± 42.45 (SD), 543.23 ± 36.73 µm, and 564.45 ± 41.26 µm, respectively. Although the CCT readings were statistically significantly thinner with the Placido-Scheimpflug system than with the other systems, there was high correlation between instruments. Peripheral corneal thickness readings were also thinner with the Placido-Scheimpflug system than with the Placido-scanning-slit system. Keratometry and anterior and posterior best-fit sphere (BFS) measurements were comparable between the 2 optical devices. Anterior and posterior maximum central elevations measured by the 2 instruments were not comparable or strongly correlated. Repeatability after 3 successive measurements was excellent for all parameters except maximum central elevation. CONCLUSIONS: Although highly correlated, with corneal thickness readings were not interchangeable between the 2 optical devices. No statistically significant differences in keratometry or BFS measurements were observed between the 2 devices. There were important discrepancies in the maximum central elevation between the 2 topographers. FINANCIAL DISCLOSURE: Drs. Gatinel and Saad are consultants to Technolas Perfect Vision. No other author has a financial or proprietary interest in any material or method mentioned.

Graft rejection and graft failure after anterior lamellar versus penetrating keratoplasty.

PURPOSE: To compare anterior lamellar keratoplasty (ALK) with the reference surgical technique (penetrating keratoplasty [PK]) for risk of rejection. DESIGN: Retrospective, comparative case series. METHODS: setting: Institutional. patients: One hundred forty-nine consecutive ALK procedures (ALK group) and 149 matched PK procedures (PK group) performed for optical indication in eyes with corneal diseases not involving the corneal endothelium (ie, keratoconus, scars after infectious keratitis, stromal dystrophies, and trauma). main outcome measures: Three-year graft survival and cumulative incidence of rejection episodes. RESULTS: The 3-year overall graft survival was 98.3% in the ALK group and 94.3% in the PK group (P = .03). The 3-year cumulative incidence of irreversible rejection was 0.0% in the ALK group and 5.2% in the PK group (P = .02). The 3-year cumulative incidence of rejection episodes was 10.0% in the ALK group and 23.2% in the PK group (P = .01). The average graft-to-rejection episode time was 21.6 ± 22.0 months in the PK group and 19.4 ± 12.7 months in the ALK group (P = .76). CONCLUSIONS: ALK techniques dramatically decrease the risk of irreversible endothelial and stromal rejection after corneal transplantation. Immune-mediated rejection episodes are observed after ALK, but its lower graft failure rate compared with PK is at least partly the result of the absence of endothelial rejection. In addition, the incidence of rejection episodes after ALK was 50% less than that observed after PK.