Louis Hoffart

Correction of Postkeratoplasty Astigmatism by Femtosecond Laser Compared with Mechanized Astigmatic Keratotomy

PURPOSE To compare the effectiveness of arcuate keratotomy (AK) performed with a femtosecond laser (FSL) or Hanna keratome (Moria, Anthony, France) for correction of postkeratoplasty astigmatism. DESIGN Prospective, randomized study. METHODS This clinical study included 20 eyes. Two groups of 10 eyes underwent AK using an FLS or keratome. Refractive and keratometric astigmatism were evaluated before surgery and 6 months after surgery. The astigmatic changes in the 2 groups were measured through arithmetic and vector analysis (Alpins method). RESULTS Six months after surgery, the mean uncorrected and corrected visual acuities did not change significantly. The mean preoperative refractive cylinder was 8.6 +/- 3.0 diopters (D) and 6.7 +/- 2.1 D, decreasing to 3.9 +/- 2.4 D and 4.7 +/- 2.4 D after laser AK and mechanized AK, respectively. The mean arithmetic change was significantly higher after laser AK, with a decrease of -55.4 +/- 20.7% (P = .011). Vector analysis showed a systematic undercorrection of astigmatism in both groups with a refractive correction index of 0.82 and 0.90 after laser AK and mechanized AK, respectively. Although no statistically significant differences were detected, a wider spread of angle of error and an almost significant difference of mean absolute angle of error (P = .052) suggest a larger misalignment of treatment during mechanized AK. All cases were uncomplicated after laser AK, 1 microperforation occurred and 1 case with off-center incisions occurred after mechanized AK. CONCLUSIONS AK performed with the femtosecond laser was effective in reducing postkeratoplasty astigmatism and has some advantages over conventional techniques. However, efficacy could be improved by a more accurate nomogram and alignment of treatment.

Corneal endothelial cell loss after cataract extraction by using ultrasound phacoemulsification versus a fluid-based system.

Purpose: To compare in vivo corneal endothelial cell loss (ECL) after fluid-based versus ultrasound phacoemulsification. Methods: In this prospective randomized study, 2 groups of 21 patients underwent phacoemulsification with ultrasound (group 1) or a fluid-based system (group 2). A “divide and conquer” method with capsular bag lens implantation was performed. Cataracts graded up to nuclear opalescence 4.9 in Lens Opacities Classification System III (LOCS III) only were included. Endothelial cell density (ECD), percent hexagonality, endothelial cell area (ECA), coefficient of variation in cell size, and central corneal pachymetry were measured preoperatively, 7 days, 1 month, and 3 months after surgery. Statistical analysis was performed by using a 2-tailed Student t test. Results: Average nuclear opalescence was identical in both groups (P = 0.908). Mean ECD was 1867 ± 451 and 2031 ± 400 cells/mm2 at 3 months postoperatively. Mean ECL was 498 ± 415 (20.6% ± 17.1%) and 302 ± 302 cells/mm2 (13.3% ± 13.2%) at 7 days, 589 ± 342 (24.3% ± 14%) and 254 ± 214 cells/mm2 (11.2% ± 9.1%) at 1 month, and 555 ± 340 (22.9% ± 14%) and 247 ± 208 cells/mm2 (10.9% ± 9.1%) at 3 months in groups 1 and 2, respectively. ECL was significantly lower for group 1 than for group 2 (P < 0.001) after the first postoperative month. A significant increase in ECA was also observed at the first and third (P = 0.012) postoperative months. Conclusions: Our study showed significantly lower ECL after phacoemulsification for a fluid-based versus an ultrasound system. The fluid-based method was safer than conventional ultrasound in cataract surgery, with a nuclear opalescence graded up to 4.9 in the LOCS III classification.

Short-term Results of Penetrating Keratoplasty Performed with the Femtec Femtosecond Laser

PURPOSE To evaluate the use of the Femtec femtosecond (fs) laser for penetrating keratoplasty (PK) in the treatment of corneal diseases. DESIGN Prospective, nonrandomized clinical study. METHODS Nine eyes of nine patients underwent surgery for PK. Five had pseudophakic bullous keratopathy, three had Fuchs dystrophy, and one presented in a keratoconus patient. A Femtec (20/10 PerfectVision; GmbH, Heidelberg, Germany) fs laser was used to create penetrating cuts on donor and recipient corneas. All patients were evaluated for uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), pachymetry, topography, and endothelial cell density (ECD). Scanning electron microscopy (SEM) was performed on corneal tissue after surgery. RESULTS All eyes were treated successfully without intraoperative complications. The mean follow-up was 6 +/- 3 months. At the last postoperative examination mean BSCVA was 20/69 and there was a significant improvement (P = .08) in both UCVA and BSCVA. Mean astigmatism was 2.9 +/- 1.2 diopters. Mean ECD was 1194 +/- 465 cells/mm(2) with a mean cell loss after surgery of 49.8% +/- 19.8%. SEM displayed smooth rectilinear cut margins and minor remaining tissue bridges. One patient presented a retinal detachment three months after surgery that was successfully treated and two subjects showed an allograft rejection. CONCLUSION Use of the Femtec fs laser was effective and safe to perform PK. Short-term visual results and refractive results are analogous to conventional PK or other fs laser-assisted PK studies. Longer-term follow-up of additional cases is necessary to precisely quantify the endothelial cell loss after fs surgery.

Wet versus Dry Age-Related Macular Degeneration in Patients with Central Field Loss: Different Effects on Maximum Reading Speed

PURPOSE To describe new, efficient predictors of maximum reading speed (MRS) in age-related macular degeneration (AMD) patients with central field loss. Type of AMD (wet versus dry) was scrutinized, because this factor seems to offer a promising model of differential visual adaptation induced by different temporal courses of disease progression. METHODS Linear mixed-effects (LME) analyses were performed on a dataset initially collected to assess the effect of interline spacing on MRS. MRS was measured with MNread-like French sentences in 89 eyes (64 dry and 25 wet) of 61 patients with AMD. Microperimetry examination was performed on each eye. The eyes were included only if they had a dense macular scotoma including the fovea, to ensure that patients used eccentric viewing. RESULTS Analyses show the unique contributions--after adjustment for the effects of other factors--of three new factors: (1) MRS was higher for wet than for dry AMD eyes; (2) an advantage of similar amplitude was found for phakic eyes compared with pseudophakic eyes; and (3) MRS decreased when distance between fixation preferred retinal locus (PRL) and fovea increased. In addition, the instantaneous slope of the relationship between scotoma area and MRS was much shallower than reported in two other studies. CONCLUSIONS The four effects improve the ability to predict MRS reliably for AMD patients. The wet/dry difference is a major finding that may result from the different time courses of the two types of disease, thus involving different types of visuomotor and attentional adaptation processes.

Small Effect of Interline Spacing on Maximal Reading Speed in Low-Vision Patients with Central Field Loss Irrespective of Scotoma Size

PURPOSE It has been suggested that crowding, the adverse low-level effect due to the proximity of adjacent stimuli, explains slow reading in low-vision patients with absolute macular scotomas. According to this hypothesis, crowding in the vertical dimension should be released by increasing the vertical spacing between lines of text. However, studies with different experimental paradigms and only a few observers have given discrepant results on this question. The purpose of this study was to investigate this issue with a large number of patients whose macular function was carefully assessed. METHODS MP1 microperimetry examination was performed for each low-vision patient. Only eyes with an absolute macular scotoma and no foveal sparing (61 patients with AMD, 90 eyes; four patients with Stargardt disease, eight eyes) were included. Maximal reading speed was assessed for each eye with French sentences designed on the MNREAD test principles. RESULTS The effect of interline spacing on maximal reading speed (MRS) was significant although small; average MRS increased by 7.1 words/min from standard to double interline spacing. The effect was weak irrespective of PRL distance from the fovea and scotoma area and regardless of whether an eccentric island of functional vision was present within the scotoma. CONCLUSIONS Increasing interline spacing is advisable only for very slow readers (<20 words/min) who want to read a few words (spot reading). Vertical crowding does not seem to be a major determinant of maximal reading speed for patients with central scotomas.

Kératoplastie lamellaire antérieure assistée par laser femtoseconde

Introduction Les keratoplasties lamellaires anterieures sont de realisation delicate et l’utilisation du laser femtoseconde dans cette indication doit permettre d’en ameliorer les resultats anatomiques et fonctionnels. Nous rapportons le premier cas de keratoplastie lamellaire anterieure assistee par un laser femtoseconde. Observation Il s’agit d’une patiente âgee de 63 ans, presentant une dystrophie corneenne anterieure de Francois, traitee par keratoplastie lamellaire anterieure assistee par laser femtoseconde ( Femtec 20/10 Perfect Vision ® ). Une decoupe corneenne lamellaire par laser femtoseconde a ete realisee a 400 μm de profondeur sur un greffon corneen, positionne sur une chambre anterieure artificielle ( Moria ® , France ), puis sur la cornee receveuse du patient. Resultats Au cours de la periode postoperatoire, le lenticule corneen etait parfaitement adapte au lit receveur avec une interface claire. L’evaluation en OCT III (Carl Zeiss Meditech, Dublin) a permis de constater une pachymetrie centrale de 713 μm avec un lit receveur extremement regulier et une epaisseur centrale de 132 μm. Discussion Les decoupes corneennes assistees par laser femtoseconde doivent en comparaison avec les decoupes mecanisees ameliorer la securite operatoire, la reproductibilite, et la predictibilite des decoupes obtenues. Une meilleure congruence du greffon limite le risque de deplacement secondaire et la meilleure regularite de l’interface doit ameliorer le resultat fonctionnel. Conclusion Les keratoplasties lamellaires anterieures assistees par laser femtoseconde Femtec 20/10 Perfectvision ® presentent de nombreux avantages pour la prise en charge des pathologies corneennes necessitant une keratoplastie lamellaire anterieure. Des etudes comparatives, multicentriques, et randomisees sont necessaires afin d’evaluer les resultats de cette technique.

Eye Movements and Reading Speed in Macular Disease: The Shrinking Perceptual Span Hypothesis Requires and Is Supported by a Mediation Analysis

PURPOSE Reading speed of patients with central field loss (CFL) correlates with the size of saccades (measured in letters per forward saccade [L/FS]). We assessed whether this effect is mediated by the total number of fixations, by the average fixation duration, or by a mixture of both. METHODS We measured eye movements (with a video eye tracker) of 35 AMD and 4 Stargardt patients (better eye decimal acuity from 0.08-0.3) while they monocularly read single-line French sentences continuously displayed on a screen. All patients had a dense scotoma covering the fovea, as assessed with MP1 microperimetry, and therefore used eccentric viewing. Results were analyzed with regression-based mediation analysis, a modeling framework that informs on the underlying factors by which an independent variable affects a dependent variable. RESULTS Reading speed and average fixation duration are negatively correlated, a result that was not observed in prior studies with CFL patients. This effect of fixation duration on reading speed is still significant when partialling out the effect of the total number of fixations (slope: -0.75, P < 0.001). Despite this large effect of fixation duration, mediation analysis shows that the effect of L/FS on reading speed is fully mediated by the total number of fixations (effect size: 0.96; CI [0.82, 1.12]) and not by fixation duration (effect size: 0.02; CI [-0.11, 0.14]). CONCLUSIONS Results are consistent with the shrinking perceptual span hypothesis: reading speed decreases with the average number of letters traversed on each forward saccade, an effect fully mediated by the total number of fixations.

Femtosecond Laser―Assisted Decagonal Penetrating Keratoplasty

PURPOSE To assess the use of a new polygonal trephination pattern for penetrating keratoplasty (PK) assisted by femtosecond laser. DESIGN Prospective, nonrandomized clinical study. METHODS Sixteen eyes underwent decagonal PK. Nine had Fuchs dystrophy, 4 had pseudophakic bullous keratopathy, 1 had experienced trauma, 1 had corneal amyloidosis, and 1 had keratoconus. A Femtec (Tecnolas PerfectVision) laser was used to create decagonal penetrating cuts on both donor and recipient corneas. All patients were evaluated for uncorrected visual acuity, best spectacle-corrected visual acuity, pachymetry, topography, and endothelial cell density. Scanning electron microscopy was performed on corneal tissue after surgery. RESULTS All eyes were treated successfully without intraoperative complications. The mean follow-up ± standard deviation was 9.75 ± 3.5 months. Mean postoperative best spectacle-corrected visual acuity was 20/53, and there was a significant improvement in both uncorrected visual acuity (P = .0019) and best spectacle-corrected visual acuity (P = .001). At 6 months, mean ± standard deviation manifest astigmatism was 1.90 ± 1.20 diopters. Mean endothelial cell density was 1502 ± 458 cells/mm². Scanning electron microscopy displayed straight decagonal cut margins and minor remaining tissue bridges. CONCLUSIONS Use of the decagonal trephination profile was effective and safe to perform PK. Short-term visual results and refractive results are encouraging compared with those of conventional PK studies. Longer-term follow-up and comparative studies are necessary to determine precisely advantages the and optimal surgical settings of this technique.

Tomographie par cohérence optique en domaine spectral du segment antérieur : la 3e dimension

PURPOSE Anterior segment imaging using optical coherence tomography (OCT) time domain technology has been used for many years. When it appeared, it was a promising technique in the analysis of the anterior segment, making it possible to reach a definition of the ocular structures comparable with histology. Now with new-generation OCT, it is possible to perform high-definition and three-dimensional imaging. MATERIAL AND METHOD A 3D OCT-1000 (Topcon, Tokyo, Japan) parameterized to obtain high-definition and 3D imaging of the iridocorneal structures. RESULTS We present a collection of images obtained using this technique. DISCUSSION Based on a very sophisticated tool for retinal and glaucoma imagery, it is now possible to obtain very-high-quality imaging of the anterior segment, which, with its great versatility, increases the value of acquiring this type of device. CONCLUSIONS The potential of 3D OCT-1000, already a very good exam for the posterior segment, and the only one to perform anterior segment three-dimensional imaging in a single acquisition, should not be neglected.

Fluorescent in situ hybridization (FISH) on corneal impression cytology specimens (CICS): study of epithelial cell survival after keratoplasty.

PURPOSE To assess corneal epithelial cell survival after keratoplasty. METHODS Corneal impression cytology (CIC) was performed on sex-mismatched corneal transplants. Fluorescent in situ hybridization (FISH) with sex chromosome-specific probes was performed to identify epithelial cell mosaicism and therefore allocate the donor or recipient origin of the cells. Twenty-four samples of corneal epithelial cells derived from 21 transplanted patients were analyzed. All patients received post-operative treatment using dexamethasone eye drops, with progressive tapering over 18 months, and nine patients also received 2% cyclosporine eye drops. RESULTS Out of the 24 samples reaching quality criteria, sex mosaicism was found in 13, demonstrating the presence of donor-derived cells at the center of the graft for at least 211 days post keratoplasty. Kaplan-Meier analysis established a median survival of donor corneal epithelial cells of 385 days. Although not statistically significant, the disappearance of donor cells seemed to be delayed and the average number of persistent cells appeared to be greater when 2% cyclosporine was used topically as an additional immunosuppressive therapy. CONCLUSIONS The combination of corneal impressions and FISH analysis is a valuable tool with negligible side effects to investigate the presence of epithelial cell mosaicism in sex-mismatched donor transplants. Epithelial cells survived at the center of the graft with a median survival of more than one year, suggesting slower epithelial turnover than previously described.