Christopher S. Sáles

The First 100 Eyes of Standardized Descemet Stripping Automated Endothelial Keratoplasty versus Standardized Descemet Membrane Endothelial Keratoplasty.

PURPOSE To compare results of the first 100 eyes of Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) that were performed with a standardized technique at a single institution. DESIGN Single-center, retrospective case series. PARTICIPANTS The first 100 eyes of standardized DSAEK and DMEK that underwent surgery for Fuchs corneal dystrophy at our center. We excluded patients with prior ocular surgery other than cataract surgery to limit confounding variables. METHODS Best spectacle-corrected visual acuity (BSCVA; in logarithm of the minimal angle of resolution [logMAR] units) was obtained and specular microscopy of donor corneal tissue was performed before surgery. Postoperative complications, BSCVA, and the percent of endothelial cell loss (ECL) recorded at 6 months were compared with the Student t test. Patients with pre-existing ocular comorbidity that impacted visual potential such as macular degeneration, amblyopia, advanced glaucoma, and other optic neuropathies were excluded from the analysis of visual acuity, but were included for the outcomes of complications and ECL. MAIN OUTCOME MEASURES Visual acuity improvement, ECL 6 months after surgery, postoperative complications, iatrogenic primary graft failure (IPGF), and rebubbling. RESULTS Of the 200 eyes, 62 DSAEK eyes and 70 DMEK eyes had 6-month BSCVA available and no vision-limiting comorbidities. Mean BSCVA increased from 0.41±0.19 logMAR and 0.27±0.11 logMAR before surgery to 0.20±0.13 logMAR and 0.11±0.13 logMAR 6 months after DSAEK and DMEK, respectively (P<0.001). Seventy-one DSAEK eyes and 70 DMEK eyes had 6-month ECL data available: ECL was 25.9±14.0% after DSAEK and 27.9±16.0% after DMEK (P=0.38). There were no IPGFs in the DSAEK cohort and there were 4 of 100 IPGFs after DMEK (P=0.12). Rebubbling was performed in 2 of 100 eyes after DSAEK and in 6 of 100 eyes after DMEK (P=0.28). CONCLUSIONS Compared with DSAEK, DMEK provided better visual recovery and comparable 6-month ECL. The DMEK group had a higher, although not statistically significant, percentage of rebubbling procedures and IPGFs.

Standardized DMEK Technique: Reducing Complications Using Prestripped Tissue, Novel Glass Injector, and Sulfur Hexafluoride (SF6) Gas.

Purpose: To report low complication rates in Descemet membrane endothelial keratoplasty (DMEK) using sulfur hexafluoride (SF6) gas, a novel glass injector, and donor tissue prestripped by an eye bank technician. Methods: A standardized technique of DMEK was performed in 80 consecutive Fuchs corneal dystrophy cases using technician-prestripped tissue, a novel glass injector, a modified Yoeruek tap technique, and an SF6 gas (20% concentration) bubble for prolonged tissue support. Twenty-five donors were premarked with an “S” stamp for intraoperative orientation. Surgery was performed by 2 experienced DMEK surgeons and 2 inexperienced cornea fellows. Complications were recorded, and the percent endothelial cell loss was calculated at 6 months postoperatively. Results: There were 5 cases that received an air bubble injection postoperatively (6% rebubble rate). There were 6 grafts that immediately failed, 2 because of excessive surgical trauma, and 4 because of upside-down graft placement documented by optical coherence tomography. None of the 25 cases with an S stamp failed. Recipient corneas cleared quickly with no clinical evidence of toxicity from the SF6 gas bubble, and the grafts experienced a mean endothelial cell loss of 27% at 6 months. Conclusions: Tissue prestripped by an eye bank technician can be safely used for DMEK surgery. SF6 gas for prolonged tissue support may reduce the rebubble rate in DMEK, with no apparent acute toxic effect. An unrecognized upside-down graft was the primary cause of graft failure in this series. Upside-down grafts may be eliminated by the use of donor tissue premarked by the eye bank with an S orientation stamp.

One-Year Outcomes from a Prospective, Randomized, Eye-to-Eye Comparison of Wavefront-Guided and Wavefront-Optimized LASIK in Myopes

OBJECTIVE To compare wavefront (WF)-guided and WF-optimized LASIK in myopes. DESIGN Prospective, randomized, eye-to-eye study. PARTICIPANTS A total of 72 eyes of 36 participants with myopia with or without astigmatism. METHODS Participants were randomized to receive WF-guided or WF-optimized LASIK with the WaveLight Allegretto Eye-Q 400-Hz excimer laser platform (Alcon, Inc., Hüenberg, Switzerland). LASIK flaps were created using the 150-kHz IntraLase iFS (Abbott Medical Optics, Santa Ana, CA). Evaluations included measurement of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), <5% and <25% contrast sensitivity, and WF aberrometry. Patients also completed a validated questionnaire detailing symptoms on a quantitative scale. MAIN OUTCOME MEASURES Safety, efficacy, predictability, refractive error, UDVA, CDVA, contrast sensitivity, and higher-order aberrations (HOAs). RESULTS The frequency with which the WF-guided and WF-optimized groups achieved postoperative UDVA of ≥ 20/16 or ≥ 20/20 and the frequency with which the groups lost 1 or 2 or more lines or maintained their preoperative CDVA were not statistically different from each other (all P > 0.05). The frequency with which the WF-guided group attained a refractive error within ± 0.25 diopters of emmetropia was higher than in the WF-optimized group (67.6%, 95% confidence interval [CI], 50.4-84.8 vs. 41.2%, 95% CI, 23.2-59.2; P = 0.03). The WF-guided groups mean UDVA was better than the WF-optimized groups UDVA by approximately 1 Early Treatment Diabetic Retinopathy Study line (-0.17 ± 0.11 logarithm of the minimum angle of resolution [logMAR], slightly <20/12 Snellen vs. -0.13 ± 0.12, slightly >20/16; P = 0.05). There were no statistically significant differences in contrast sensitivity, astigmatism, coma, or higher-order root mean square error between the groups (all P > 0.05), but the WF-guided group had less trefoil compared with the WF-optimized group (0.14 ± 0.07 vs. 0.20 ± 0.09; P < 0.01). There were no statistically significant differences in subjective parameters between the groups (all P > 0.05). CONCLUSIONS Wavefront-guided and WF-optimized LASIK using the Alcon WaveLight Allegretto Eye-Q 400-Hz excimer laser platform provide similar results in myopic patients; however, the WF-guided approach may yield small gains in visual acuity, predictability, and HOAs.

Stamping an S on DMEK Donor Tissue to Prevent Upside-Down Grafts: Laboratory Validation and Detailed Preparation Technique Description.

Purpose: To report endothelial cell loss (ECL) caused by a novel S-stamp preparation technique for Descemet membrane endothelial keratoplasty (DMEK). Methods: Six cadaveric human corneas were prepared for DMEK transplantation using a single standardized technique, including the application of a dry ink gentian violet S-stamp to the stromal side of Descemet membrane. Endothelial cell death was evaluated and quantified using computerized analysis of vital dye staining. Results: ECL caused by the S-stamp was 0.6% (range 0.1%–1.0%), which comprised less than one-tenth of the total ECL caused by our preparation of the DMEK graft from the start to finish, including recovery, prestripping, S-stamping, and trephination (13.7% total ECL, range 9.9%–17.6%). Conclusions: Our novel S-stamp donor tissue preparation technique is intuitive to learn and holds the promise of preventing iatrogenic primary graft failure due to upside-down grafts without causing unacceptable increases in ECL.

Managing residual refractive error after cataract surgery

We present a review of keratorefractive and intraocular approaches to managing residual astigmatic and spherical refractive error after cataract surgery, including laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), arcuate keratotomy, intraocular lens (IOL) exchange, piggyback IOLs, and light-adjustable IOLs. Currently available literature suggests that laser vision correction, whether LASIK or PRK, yields more effective and predictable outcomes than intraocular surgery. Piggyback IOLs with a rounded-edge profile implanted in the sulcus may be superior to IOL exchange, but both options present potential risks that likely outweigh the refractive benefits except in cases with large residual spherical errors. The light-adjustable IOL may provide an ideal treatment to pseudophakic ametropia by obviating the need for secondary invasive procedures after cataract surgery, but it is not widely available nor has it been sufficiently studied.

Corneal Sensation and Dry Eye Symptoms after Conventional versus Inverted Side-Cut Femtosecond LASIK : A Prospective Randomized Study

PURPOSE To compare corneal sensation and self-reported dry eye symptoms after femtosecond-assisted LASIK with conventional versus inverted side cuts. DESIGN Prospective, randomized, eye-to-eye study. PARTICIPANTS A total of 120 eyes in 60 participants with myopia. METHODS Fellow eyes were randomized to receive femtosecond-assisted LASIK with a conventional 70-degree side cut made with the 60 kHz IntraLase FS (Abbott Medical Optics, Santa Ana, CA) or an inverted 130-degree side cut made with the 150 kHz IntraLase iFS (Abbott Medical Optics). Cochet-Bonnet aesthesiometry (Luneau Ophthalmologia, Chartes, France) measured corneal sensation (60 mm = normal sensation; <60 mm = depressed sensation) preoperatively and at postoperative months 1, 3, 6, and 12. Participants also completed serial dry eye surveys using the same subscales (frequency, severity, bothersome) as the validated, Rasch-tested, linear-scaled Quality of Vision questionnaire. MAIN OUTCOME MEASURES Objective corneal sensation and self-reported light sensitivity, dryness, foreign body sensation, and pain/discomfort. RESULTS Preoperative corneal sensation as measured by mean Cochet-Bonnet aethesiometry was equal between the inverted and conventional side cut groups but was better in eyes with an inverted side cut compared with a conventional side cut at all postoperative months (inverted vs. conventional: 1 month, 14.5 vs. 13.2 mm; 3 months, 24.9 vs. 18.4 mm; 6 months, 51.2 vs. 42.6 mm; 12 months, 59.8 vs. 58.3 mm; all P ≤ 0.02). None of the subjective dry eye parameters demonstrated statistically significant differences between the groups at any time point. CONCLUSIONS The LASIK flaps with an inverted side cut are associated with superior recovery of corneal sensation compared with flaps with a conventional side cut during the first postoperative year; however, this may not translate to significant improvements in subjective dry eye symptoms.

One-year eye-to-eye comparison of wavefront-guided versus wavefront-optimized laser in situ keratomileusis in hyperopes

Background To compare wavefront (WF)-guided and WF-optimized laser in situ keratomileusis (LASIK) in hyperopes with respect to the parameters of safety, efficacy, predictability, refractive error, uncorrected distance visual acuity, corrected distance visual acuity, contrast sensitivity, and higher order aberrations. Methods Twenty-two eyes of eleven participants with hyperopia with or without astigmatism were prospectively randomized to receive WF-guided LASIK with the VISX CustomVue S4 IR or WF-optimized LASIK with the WaveLight Allegretto Eye-Q 400 Hz. LASIK flaps were created using the 150-kHz IntraLase iFS. Evaluations included measurement of uncorrected distance visual acuity, corrected distance visual acuity, <5% and <25% contrast sensitivity, and WF aberrometry. Patients also completed a questionnaire detailing symptoms on a quantitative grading scale. Results There were no statistically significant differences between the groups for any of the variables studied after 12 months of follow-up (all P>0.05). Conclusion This comparative case series of 11 subjects with hyperopia showed that WF-guided and WF-optimized LASIK had similar clinical outcomes at 12 months.

Comparison of self-reported quality of vision outcomes after myopic LASIK with two femtosecond lasers: a prospective, eye-to-eye study

Purpose To compare self-reported quality of vision (QoV) outcomes after myopic LASIK (laser-assisted in situ keratomileusis) with two femtosecond lasers. Design Prospective, randomized, eye-to-eye study. Methods Consecutive myopic patients were treated with wavefront-guided LASIK bilaterally. Eyes were randomized according to ocular dominance. The flap of one eye was made with the IntraLase FS 60 kHz femtosecond laser with a conventional 70° side-cut, and the flap of the fellow eye was made with the IntraLase iFS 150 kHz femtosecond laser with an inverted 130° side-cut. Patients completed the validated, Rasch-tested, linear-scaled 30-item QoV questionnaire preoperatively and at Months 1, 3, 6, and 12. Results The study enrolled 120 fellow eyes in 60 patients. None of the measured QoV parameters exhibited statistically significant differences between the groups preoperatively or at any postoperative time point. Conclusion Creating LASIK flaps with an inverted side-cut using a 150 kHz femtosecond laser and with a conventional 70° side-cut using a 60 kHz femtosecond laser resulted in no significant differences in self-reported QoV assessed by the QoV questionnaire.

Comparison of ocular aberrations measured by a Fourier-based Hartmann-Shack and Zernike-based Tscherning aberrometer before and after laser in situ keratomileusis

Purpose To assess agreement between a Hartmann‐Shack aberrometer (Wavescan) and a Tscherning aberrometer (Wavelight Allegro Analyzer) and their respective agreement with manifest refraction before and after laser in situ keratomileusis (LASIK). Setting Stanford Eye Laser Center, California, USA. Design Prospective comparative observational study. Methods Multiple readings were obtained both aberrometers preoperatively and 12 months after wavefront‐guided LASIK. Sphere, cylinder, spherical equivalent (SE), defocus Z(2,0), astigmatism Z(2,2), spherical aberration Z(4,0), coma Z(3,1), trefoil Z(3,3), and total higher‐order aberrations (HOAs) were compared using intraclass correlation coefficients (ICCs) (perfect agreement = 1; disagreement = 0). Results In the 100 study eyes, preoperative agreement was good to excellent between the aberrometers for the parameters of defocus, astigmatism, and spherical aberration (ICC: 0.8, 0.9, and 0.7, respectively) but was poor for coma, trefoil, and total HOAs (ICC: 0.6, –0.2, and 0.4, respectively). At 12 months, ICCs worsened for all parameters (ICC: defocus = 0.6; astigmatism = 0.2; spherical aberration = 0.6; coma = 0.4; trefoil = –0.3; total HOAs = 0.4). Preoperative agreement of sphere, cylinder, and SE was good to excellent between the manifest refraction and both aberrometers (ICC Hartmann‐Shack: 0.98, 0.95, and 0.97, respectively; ICC Tscherning: 0.97, 0.92, and 0.98, respectively). However, agreement was poor to fair between the manifest refraction and both aberrometers at 12 months (ICC Hartmann‐Shack: 0.4, 0.1, and 0.4, respectively; ICC Tscherning: 0.03, 0.02, and 0.2, respectively). Conclusions Although some HOAs measured with both aberrometers agreed preoperatively, such agreement might not persist after LASIK. Spherocylinder measurements with both aberrometers seemed to agree closely with the manifest refraction before LASIK, but not at 12 months. Financial Disclosure Dr. Manche has equity in Calhoun Vision, Inc., Krypton Vision, Seros Medical, LLC, and Veralas and is a consultant to Best Doctors, Gerson Lehrman Group.