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Papers by David Touboul

Journal of Cataract and Refractive Surgery, 2015

To evaluate the safety and efficacy of wavefront-guided laser in situ keratomileusis (LASIK) for ... more To evaluate the safety and efficacy of wavefront-guided laser in situ keratomileusis (LASIK) for the correction of low to high myopia and myopic astigmatism using data derived from a new-generation Hartmann-Shack aberrometer. Refractive Surgery Unit, Bordeaux Hospital University, France. Retrospective case series. This retrospective study analyzed the initial group of eyes treated with wavefront-guided LASIK for myopia and myopic astigmatism using the Visx S4IR excimer laser and wavefront data derived from a new Hartmann-Shack aberrometer (iDesign Advanced Wavescan aberrometer). Refractive (refraction and refractive accuracy) and visual outcomes (uncorrected [UDVA] and corrected [CDVA] distance visual acuities) were recorded 3 months postoperatively. The study included 100 eyes of 50 consecutively treated patients. The mean decimal UDVA improved from 0.1 ± 0.1 (SD) preoperatively to 1.1 ± 0.15 postoperatively (P < .01). A monocular UDVA of 20/16, 20/20, and 20/25 were achieved in 76.6%, 94.4%, and 96.6% of eyes, respectively. The postoperative manifest spherical equivalent was within ±0.5 diopter in all eyes. No eye lost 2 or more lines of CDVA, and 29.2% of the eyes gained 1 or more lines of CDVA. Wavefront-guided LASIK performed using data derived from the new Hartmann-Shack aberrometer was safe, effective, and predictable for treating myopia and myopic astigmatism. No author has a financial or proprietary interest in any material or method mentioned.

La Revue de Médecine Interne, 2006

Introduction.-L'atteinte ophtalmologique et des glandes salivaires dans le lymphome du manteau es... more Introduction.-L'atteinte ophtalmologique et des glandes salivaires dans le lymphome du manteau est rare. Fait clinique.-Un patient de 67 ans présentait un syndrome sec primitif confirmé par l'histologie des glandes salivaires accessoires. Secondairement, il présentait un lymphome du manteau. Discussion.-L'absence de spécificité de l'histologie et la présentation atypique d'un syndrome de Gougerot-Sjögren doivent inciter à une étude immunohistochimique complémentaire de la biopsie des glandes salivaires.

Journal of Refractive Surgery, 2013

To analyze the induced corneal higher order aberrations (HOAs) after wavefront-optimized ablation... more To analyze the induced corneal higher order aberrations (HOAs) after wavefront-optimized ablation. Sixty-four myopic eyes that underwent wavefront-optimized myopic LASIK were divided into three groups based on spherical equivalent (SE): low myopia group (23 eyes with SE <-3.00 diopters [D]); moderate myopia group (27 eyes with SE between -3.00 and -6.00 D); and high myopia group (14 eyes with SE >-6.00 D). Total corneal HOA, corneal spherical aberrations, corneal coma through a 6-mm pupil size, and corneal eccentricity were measured with a dual Scheimpflug imaging device preoperatively and 3 months after surgery. An overall increase in total corneal HOA was observed with a mean of 0.18±0.18 μm (P<.01), although this induction was not statistically significant in the low myopic group with a mean of 0.006±0.15 μm (P=.85). Root-mean-square spherical aberration varied the most after myopic ablation, with an overall induction of positive spherical aberration of 0.27±0.25 μm (P<.001). Although the wavefront-optimized profile was designed to preserve the preoperative HOAs of the total eye, a significant induction of the corneal HOAs after myopic treatment was observed. The magnitude of the induced corneal HOA was related to the amount of intended correction. Corneal wavefront profiles do not reflect the visual performance; however, they provide relevant information, which may help in optimizing new laser treatment algorithms.

Journal of Cataract and Refractive Surgery, 2008

The ocular response analyzer (ORA) (Reichert, Inc.) was used in the case of a middle-aged man who... more The ocular response analyzer (ORA) (Reichert, Inc.) was used in the case of a middle-aged man who developed unilateral corneal ectasia after bilateral laser in situ keratomileusis (LASIK). The preoperative refraction was similar in the 2 eyes. Post-LASIK ectasia was central in the left eye; topography was oblate in the right eye. The ORA values consisted of the mean of 4 measurements. Corneal hysteresis and corneal resistance factor were almost equal in the ectatic eye and the nonectatic eye. However, significant between-eye differences in the morphology of the signals were noted, most prominently in the lower amplitude of the applanation peaks in the ectatic eye. The shape of the applanation signal yielded important information in addition to corneal hysteresis and corneal resistance factor.

Journal of Cataract and Refractive Surgery, 2012

To define the contribution of the corneal epithelium in corneal topography in keratoconus and dis... more To define the contribution of the corneal epithelium in corneal topography in keratoconus and discuss the implications regarding combined topography-guided photorefractive keratectomy and corneal collagen crosslinking (CXL). French National Reference Center for Keratoconus, Bordeaux, France. Case series. Specular topographies were performed before and immediately after epithelial removal during conventional CXL surgery in patients with keratoconus. The study included 1 eye with forme fruste keratoconus, 4 eyes in Krumeich stage I, and 3 eyes in stage II. The mean simulated maximum keratometry (K) increased by 2.87 diopters (D) after epithelial removal. The mean effective refractive power increased by a mean of 4.01 D and the astigmatic refractive power, by a mean of 2.17 D. The difference in mean axis deviation was not significant. The mean inferior-superior ratio irregularity index increased 1.51 units. All K and refractive readings except astigmatic refractive axis were significantly increased after epithelial removal. All regularity indices increased significantly without the epithelium. The amplitude of variations in K readings made it difficult to predict the refractive changes after custom laser photoablation based on epithelial-based topography. The astigmatism refractive axis did not change significantly; therefore, this axis could be useful for astigmatic corrections, whereas the spherical component would not be useful. Topographic changes after epithelial removal can be important but not intuitive in keratoconus eyes. This should be considered in custom topography-guided photoablation strategies when attempting to correct refractive errors at the time of CXL.

Journal of Cataract and Refractive Surgery, 2011

DESIGN: Case series. METHODS: This retrospective uncontrolled double-center study comprised eyes ... more DESIGN: Case series. METHODS: This retrospective uncontrolled double-center study comprised eyes with progressive keratoconus. Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), corneal pachymetry, endothelial cell count, and corneal hysteresis and corneal resistance factor were evaluated at baseline and at 1, 3, 6, and 12 months. RESULTS: One hundred forty-two eyes were enrolled in the study. At 6 months, the CDVA had stabilized in 53 eyes (48.1%), improved in 36 eyes (32.7%), and decreased in 18 eyes (16.3%). At 12 months, the CDVA had stabilized in 31 eyes (47.6%), improved in 26 eyes (40.0%), and decreased in 8 eyes (12%). At 6 months, keratoconus progression had stopped in 51 eyes (49.03%) and the maximum keratometry (K) value had decreased by more than 1.0 diopter (D) in 37 eyes (35.5%); it continued to progress in 16 eyes (15.3%). At 12 months, keratoconus progression had stopped in 42 eyes (68.8%) and the maximum K value had decreased by more than 2.0 D in 13 eyes (21.3%). The complication rate with loss of vision was 3.5%. CONCLUSIONS: Ultraviolet-A light associated with riboflavin CXL is an efficient procedure to stabilize and improve progressive keratoconus. The results reinforce previous studies highlighting the efficacy and safety of the procedure. A large prospective randomized clinical trial is needed.

Journal Français d'Ophtalmologie, 2005

ABSTRACT Purpose Despite progress in mechanical microkeratomes used in refractive surgery, mechan... more ABSTRACT Purpose Despite progress in mechanical microkeratomes used in refractive surgery, mechanical complications during cutting of the cornea still occur. Cutting by laser could reduce these complications and to date, the femtosecond laser is the only potential candidate for this purpose. Our study reports preliminary results with a femtosecond microkeratome for cutting porcine corneas ex vivo. Methods We first examined the fundamental principles of the interaction between the femtosecond laser and the corneal stroma, including the volume of tissue lesions, the laser breakdown threshold of the stroma and the laser ablation selectivity. We then analyzed the quality of cutting corneal flaps with the laser, focusing on collateral tissue effects and the roughness of the interfaces observed both histologically and with scanning electron microscopy. Results The photoablative and photodisruptive effects were very similar with the femtosecond laser. This characteristic is specific to ultrashort impulsion photodisruptor lasers and allows for a very precise surgical procedure. The laser-induced breakdown threshold of porcine corneal stroma was found to be 0.55 J/cm2 Collateral tissue lesions were on the submicrometer level. The roughness of the stromal bed was optimal for postage stamp cutting, providing very many contiguous points of impact which were as spherical as possible. Conclusion Corneal photodisruption with a femtosecond laser is reproducible and extremely accurate. The optomechanical parameters involved with this technique require great technological skill and should be placed in experienced hands.

Journal Français d'Ophtalmologie, 2009

Cornée COMMUNICATIONS ORALES récidive inflammatoire a été notée en dehors de la zone greffée et a... more Cornée COMMUNICATIONS ORALES récidive inflammatoire a été notée en dehors de la zone greffée et a nécessité une adaptation du traitement d'entretien. Dans tous les cas, une amélioration ou une stabilisation de l'acuité visuelle a été notée. Discussion : Selon les indications, la greffe lamellaire cornéo-sclérales peut jouer un rôle architectonique (en cas de perforation avérée ou imminente), visuel (en cas d'astigmatisme important ou de perforation) ou immunologique (en limitant l'accès des médiateurs de l'inflammation sur la zone amincie). Conclusion : La greffe lamellaire cornéo-sclérale est une arme particulièrement efficace dans l'arsenal thérapeutique des amincissements cornéens périphériques dégénératifs ou immunologiques. Leur réalisation au cours des affections immunologiques ne se conçoit qu'après prise en charge de l'inflammation causale. 311 Greffes cornéennes endothéliales dans les dystrophies de Fuchs. Endothelial keratopasty in Fuchs endothelial corneal dystrophy.

Journal Français d'Ophtalmologie, 2013

The endothelio-descemetic interface (EDI) of a deep anterior lamellar keratoplasty (DALK) may bec... more The endothelio-descemetic interface (EDI) of a deep anterior lamellar keratoplasty (DALK) may become the locus of a neovascular proliferation. Bevacizumab (Avastin) is an antiangiogenic alternative available for curative treatment in deep corneal neovascularization. We report the case of a 49-year-old woman who had received two arcuate relaxing incisions for high astigmatism after DALK. She developed graft rejection associated with significant neovascular stromal invasion in the EDI of the graft-host interface. Two subconjunctival injections of bevacizumab 1 month apart as well as thermocauterization of the feeding vessel were necessary and effective. No recurrence has been observed after 2 years of follow-up. Corneal neovascularization can be a cause of DALK rejection. A combination of anti-antiangiogenic and physical methods may abort graft rejection and permanently restore graft function.

Journal Français d'Ophtalmologie, 2011

Investigative Opthalmology & Visual Science, 2012

American Journal of Ophthalmology, 2013

To develop a method for automatizing the detection of subclinical keratoconus based on a tree cla... more To develop a method for automatizing the detection of subclinical keratoconus based on a tree classification. DESIGN: Retrospective case-control study. METHODS: SETTING: University Hospital of Bordeaux. PARTICIPANTS: A total of 372 eyes of 197 patients were enrolled: 177 normal eyes of 95 subjects, 47 eyes of 47 patients with forme fruste keratoconus, and 148 eyes of 102 patients with keratoconus. OBSERVATION PROCEDURE: All eyes were imaged with a dual Scheimpflug analyzer. Fifty-five parameters derived from anterior and posterior corneal measurements were analyzed for each eye and a machine learning algorithm, the classification and regression tree, was used to classify the eyes into the 3 above-mentioned conditions. MAIN OUTCOME MEASURES: The performance of the machine learning algorithm for classifying eye conditions was evaluated, and the curvature, elevation, pachymetric, and wavefront parameters were analyzed in each group and compared. RESULTS: The discriminating rules generated with the automated decision tree classifier allowed for discrimination between normal and keratoconus with 100% sensitivity and 99.5% specificity, and between normal and forme fruste keratoconus with 93.6% sensitivity and 97.2% specificity. The algorithm selected as the most discriminant variables parameters related to posterior surface asymmetry and thickness spatial distribution. CONCLUSION: The machine learning classifier showed very good performance for discriminating between normal corneas and forme fruste keratoconus and provided a tool that is closer to an automated medical reasoning. This might help in the surgical decision before refractive surgery by providing a good sensitivity in detecting ectasia-susceptible corneas.

Cornea, 2012

We describe a case of a 52-year-old man in whom the appearance of an air bubble developed, trappe... more We describe a case of a 52-year-old man in whom the appearance of an air bubble developed, trapped within the Descemet membrane (DM), that occurred during a planned deep anterior lamellar keratoplasty using the "big bubble" technique. This situation can occur because Descemet membrane's anatomic structure can be opened by the gas dissection; this complication may result in unanticipated results during and after this type of surgery. Surgeons should be aware of this specific risk, so they will recognize it when it occurs. Optical coherence tomography (OCT) imaging and surgical management are presented.

American Journal of Ophthalmology, 2013

ABSTRACT Purpose: To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) u... more ABSTRACT Purpose: To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) using a modified “big-bubble” technique. Setting: Retrospective, interventional case series of eyes operated at a private hospital by a single surgeon (MB). Methods: Review of the medical records of all consecutive patients who underwent a modified DALK (small “big-bubble“ technique) between April 2012 to December 2013 at Villa Igea Hospital, Forli'. The standardized procedure included: 1) Partial thickness 9mm trephination; 2) Pneumatic dissection of the stroma; 3) Removal of about half thickness of the anterior stroma within the 9.0 mm incision; 4) Marking of the central 6.0 mm optical zone, perforation of the bubble and removal of the deep stroma with exposure of Descemet within the 6.0 mm zone; 5) Suturing of a donor lamella, 350-400 micron in thickness and 9.0 mm in diameter, obtained by means of microkeratome-assisted dissection. When pneumatic dissection failed, Descemet was dissected by hand over the same 6 mm central optical zone. Complete suture removal was performed 12 months postoperatively. Main outcome measures were best spectacle-corrected visual acuity (BSCVA), and endothelial cell density (ECD). Differences between groups were tested with a two-tailed Student’s t-test (p values <0.05 were considered significant). Results: Seventy-two eyes of 72 patients were included in the study. Indications for surgery were keratoconus (n=66, 91.6%), herpetic scars (n=2, 2.7%) and corneal dystrophy, exposure scar, corneal neoplastic infiltration, as well as scar secondary to trichiasis (n=1, %1.4 each). Pneumatic dissection succeeded in 32 (44.4%), and failed in 40 eyes (55.5%) patients. Stromal dissection was completed by hand in 39 of 40 eyes: microperforation occurred in 4 eyes (only in one patient after successful formation of a big bubble) but the procedure could be completed uneventfully. Macroperforation occurred in 1 eye and required conversion into mushroom keratoplasty. The average follow-up time was 7.4 months (range=3 to 18 months). The overall mean BSCVA was 0.6±0.2 and the mean ECD was 2060±355cells/mm2. In those eyes with all sutures out (n=15), BSCVA improved significantly from 0.52±0.14 before, to 0.74±0.16 (p<0.005) after complete suture removal. No significant difference in BSCVA (p = 0.9) could be found between eyes with successful and eyes with failed pneumatic dissection (0.58±0.25 versus 0.58±0.21). Postoperative complications included partial graft melting (n=2) requiring graft exchange in one case, stromal rejection (n=1) and high-degree astigmatism requiring relaxing incisions (n=1). Conclusions: The results of small “big-bubble” DALK exposing only the central 6 mm of Descemet’s membrane compare favorably to those of conventional big bubble surgery. However, the modification offers the refractive advantages of a 9.0 mm graft, the safety of performing a descemetic dissection only over a limited area, and the elimination of irregularities in the surgical wound, as both the graft edge and the recipient edge need no hand refinement. Complications are rare and if pneumatic dissection fails, the procedure can be completed by hand in almost all cases without affecting final visual acuity.

Journal of Refractive Surgery, 2013

To compare the discriminating ability of corneal elevation generated by a dual Scheimpflug analyz... more To compare the discriminating ability of corneal elevation generated by a dual Scheimpflug analyzer calculated with different reference surfaces for distinguishing normal corneas from those with keratoconus and subclinical keratoconus. A total of 391 eyes of 208 patients were prospectively enrolled in the study and divided into three groups: 167 eyes of 113 patients with keratoconus, 47 contralateral topographically normal eyes of patients with clinically evident keratoconus in the fellow eye, and 177 eyes of 95 refractive surgery candidates with normal corneas. All eyes were measured with a dual Scheimpflug analyzer (GALILEI Analyzer; Ziemer Ophthalmic Systems AG, Port, Switzerland). Maximum elevation values were recorded within the central 5-mm diameter in both anterior and posterior elevation maps. Discriminating ability of corneal elevation measurements obtained by best-fit toric and aspheric (BFTA) and best-fit sphere (BFS) reference surfaces were compared by receiver operator characteristic (ROC) curves. ROC curve analysis showed that corneal elevation measured by BFTA had a significantly better ability than with BFS for distinguishing normal corneas from those with keratoconus and forme fruste keratoconus (P = .01). Posterior elevation measured by BFTA had a significantly higher predictive accuracy for forme fruste keratoconus than anterior elevation with an area under ROC curves of 0.88 and 0.80, respectively (P = .01). The sensitivity and specificity achieved with the maximum posterior elevation for detecting keratoconus and forme fruste keratoconus were 99% and 99% for keratoconus and 82% and 80% for forme fruste keratoconus with the cut-off value at 16 and 13 μm, respectively. The ability to discriminate between normal cornea and forme fruste keratoconus with elevation parameters was significantly improved by using BFTA instead of BFS reference surface.

American Journal of Ophthalmology, 2013

ABSTRACT Purpose: To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) u... more ABSTRACT Purpose: To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) using a modified “big-bubble” technique. Setting: Retrospective, interventional case series of eyes operated at a private hospital by a single surgeon (MB). Methods: Review of the medical records of all consecutive patients who underwent a modified DALK (small “big-bubble“ technique) between April 2012 to December 2013 at Villa Igea Hospital, Forli'. The standardized procedure included: 1) Partial thickness 9mm trephination; 2) Pneumatic dissection of the stroma; 3) Removal of about half thickness of the anterior stroma within the 9.0 mm incision; 4) Marking of the central 6.0 mm optical zone, perforation of the bubble and removal of the deep stroma with exposure of Descemet within the 6.0 mm zone; 5) Suturing of a donor lamella, 350-400 micron in thickness and 9.0 mm in diameter, obtained by means of microkeratome-assisted dissection. When pneumatic dissection failed, Descemet was dissected by hand over the same 6 mm central optical zone. Complete suture removal was performed 12 months postoperatively. Main outcome measures were best spectacle-corrected visual acuity (BSCVA), and endothelial cell density (ECD). Differences between groups were tested with a two-tailed Student’s t-test (p values <0.05 were considered significant). Results: Seventy-two eyes of 72 patients were included in the study. Indications for surgery were keratoconus (n=66, 91.6%), herpetic scars (n=2, 2.7%) and corneal dystrophy, exposure scar, corneal neoplastic infiltration, as well as scar secondary to trichiasis (n=1, %1.4 each). Pneumatic dissection succeeded in 32 (44.4%), and failed in 40 eyes (55.5%) patients. Stromal dissection was completed by hand in 39 of 40 eyes: microperforation occurred in 4 eyes (only in one patient after successful formation of a big bubble) but the procedure could be completed uneventfully. Macroperforation occurred in 1 eye and required conversion into mushroom keratoplasty. The average follow-up time was 7.4 months (range=3 to 18 months). The overall mean BSCVA was 0.6±0.2 and the mean ECD was 2060±355cells/mm2. In those eyes with all sutures out (n=15), BSCVA improved significantly from 0.52±0.14 before, to 0.74±0.16 (p<0.005) after complete suture removal. No significant difference in BSCVA (p = 0.9) could be found between eyes with successful and eyes with failed pneumatic dissection (0.58±0.25 versus 0.58±0.21). Postoperative complications included partial graft melting (n=2) requiring graft exchange in one case, stromal rejection (n=1) and high-degree astigmatism requiring relaxing incisions (n=1). Conclusions: The results of small “big-bubble” DALK exposing only the central 6 mm of Descemet’s membrane compare favorably to those of conventional big bubble surgery. However, the modification offers the refractive advantages of a 9.0 mm graft, the safety of performing a descemetic dissection only over a limited area, and the elimination of irregularities in the surgical wound, as both the graft edge and the recipient edge need no hand refinement. Complications are rare and if pneumatic dissection fails, the procedure can be completed by hand in almost all cases without affecting final visual acuity.

Journal of Cataract and Refractive Surgery, 2015

To evaluate the safety and efficacy of wavefront-guided laser in situ keratomileusis (LASIK) for ... more To evaluate the safety and efficacy of wavefront-guided laser in situ keratomileusis (LASIK) for the correction of low to high myopia and myopic astigmatism using data derived from a new-generation Hartmann-Shack aberrometer. Refractive Surgery Unit, Bordeaux Hospital University, France. Retrospective case series. This retrospective study analyzed the initial group of eyes treated with wavefront-guided LASIK for myopia and myopic astigmatism using the Visx S4IR excimer laser and wavefront data derived from a new Hartmann-Shack aberrometer (iDesign Advanced Wavescan aberrometer). Refractive (refraction and refractive accuracy) and visual outcomes (uncorrected [UDVA] and corrected [CDVA] distance visual acuities) were recorded 3 months postoperatively. The study included 100 eyes of 50 consecutively treated patients. The mean decimal UDVA improved from 0.1 ± 0.1 (SD) preoperatively to 1.1 ± 0.15 postoperatively (P < .01). A monocular UDVA of 20/16, 20/20, and 20/25 were achieved in 76.6%, 94.4%, and 96.6% of eyes, respectively. The postoperative manifest spherical equivalent was within ±0.5 diopter in all eyes. No eye lost 2 or more lines of CDVA, and 29.2% of the eyes gained 1 or more lines of CDVA. Wavefront-guided LASIK performed using data derived from the new Hartmann-Shack aberrometer was safe, effective, and predictable for treating myopia and myopic astigmatism. No author has a financial or proprietary interest in any material or method mentioned.

La Revue de Médecine Interne, 2006

Introduction.-L'atteinte ophtalmologique et des glandes salivaires dans le lymphome du manteau es... more Introduction.-L'atteinte ophtalmologique et des glandes salivaires dans le lymphome du manteau est rare. Fait clinique.-Un patient de 67 ans présentait un syndrome sec primitif confirmé par l'histologie des glandes salivaires accessoires. Secondairement, il présentait un lymphome du manteau. Discussion.-L'absence de spécificité de l'histologie et la présentation atypique d'un syndrome de Gougerot-Sjögren doivent inciter à une étude immunohistochimique complémentaire de la biopsie des glandes salivaires.

Journal of Refractive Surgery, 2013

To analyze the induced corneal higher order aberrations (HOAs) after wavefront-optimized ablation... more To analyze the induced corneal higher order aberrations (HOAs) after wavefront-optimized ablation. Sixty-four myopic eyes that underwent wavefront-optimized myopic LASIK were divided into three groups based on spherical equivalent (SE): low myopia group (23 eyes with SE <-3.00 diopters [D]); moderate myopia group (27 eyes with SE between -3.00 and -6.00 D); and high myopia group (14 eyes with SE >-6.00 D). Total corneal HOA, corneal spherical aberrations, corneal coma through a 6-mm pupil size, and corneal eccentricity were measured with a dual Scheimpflug imaging device preoperatively and 3 months after surgery. An overall increase in total corneal HOA was observed with a mean of 0.18±0.18 μm (P<.01), although this induction was not statistically significant in the low myopic group with a mean of 0.006±0.15 μm (P=.85). Root-mean-square spherical aberration varied the most after myopic ablation, with an overall induction of positive spherical aberration of 0.27±0.25 μm (P<.001). Although the wavefront-optimized profile was designed to preserve the preoperative HOAs of the total eye, a significant induction of the corneal HOAs after myopic treatment was observed. The magnitude of the induced corneal HOA was related to the amount of intended correction. Corneal wavefront profiles do not reflect the visual performance; however, they provide relevant information, which may help in optimizing new laser treatment algorithms.

Journal of Cataract and Refractive Surgery, 2008

The ocular response analyzer (ORA) (Reichert, Inc.) was used in the case of a middle-aged man who... more The ocular response analyzer (ORA) (Reichert, Inc.) was used in the case of a middle-aged man who developed unilateral corneal ectasia after bilateral laser in situ keratomileusis (LASIK). The preoperative refraction was similar in the 2 eyes. Post-LASIK ectasia was central in the left eye; topography was oblate in the right eye. The ORA values consisted of the mean of 4 measurements. Corneal hysteresis and corneal resistance factor were almost equal in the ectatic eye and the nonectatic eye. However, significant between-eye differences in the morphology of the signals were noted, most prominently in the lower amplitude of the applanation peaks in the ectatic eye. The shape of the applanation signal yielded important information in addition to corneal hysteresis and corneal resistance factor.

Journal of Cataract and Refractive Surgery, 2012

To define the contribution of the corneal epithelium in corneal topography in keratoconus and dis... more To define the contribution of the corneal epithelium in corneal topography in keratoconus and discuss the implications regarding combined topography-guided photorefractive keratectomy and corneal collagen crosslinking (CXL). French National Reference Center for Keratoconus, Bordeaux, France. Case series. Specular topographies were performed before and immediately after epithelial removal during conventional CXL surgery in patients with keratoconus. The study included 1 eye with forme fruste keratoconus, 4 eyes in Krumeich stage I, and 3 eyes in stage II. The mean simulated maximum keratometry (K) increased by 2.87 diopters (D) after epithelial removal. The mean effective refractive power increased by a mean of 4.01 D and the astigmatic refractive power, by a mean of 2.17 D. The difference in mean axis deviation was not significant. The mean inferior-superior ratio irregularity index increased 1.51 units. All K and refractive readings except astigmatic refractive axis were significantly increased after epithelial removal. All regularity indices increased significantly without the epithelium. The amplitude of variations in K readings made it difficult to predict the refractive changes after custom laser photoablation based on epithelial-based topography. The astigmatism refractive axis did not change significantly; therefore, this axis could be useful for astigmatic corrections, whereas the spherical component would not be useful. Topographic changes after epithelial removal can be important but not intuitive in keratoconus eyes. This should be considered in custom topography-guided photoablation strategies when attempting to correct refractive errors at the time of CXL.

Journal of Cataract and Refractive Surgery, 2011

DESIGN: Case series. METHODS: This retrospective uncontrolled double-center study comprised eyes ... more DESIGN: Case series. METHODS: This retrospective uncontrolled double-center study comprised eyes with progressive keratoconus. Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), corneal pachymetry, endothelial cell count, and corneal hysteresis and corneal resistance factor were evaluated at baseline and at 1, 3, 6, and 12 months. RESULTS: One hundred forty-two eyes were enrolled in the study. At 6 months, the CDVA had stabilized in 53 eyes (48.1%), improved in 36 eyes (32.7%), and decreased in 18 eyes (16.3%). At 12 months, the CDVA had stabilized in 31 eyes (47.6%), improved in 26 eyes (40.0%), and decreased in 8 eyes (12%). At 6 months, keratoconus progression had stopped in 51 eyes (49.03%) and the maximum keratometry (K) value had decreased by more than 1.0 diopter (D) in 37 eyes (35.5%); it continued to progress in 16 eyes (15.3%). At 12 months, keratoconus progression had stopped in 42 eyes (68.8%) and the maximum K value had decreased by more than 2.0 D in 13 eyes (21.3%). The complication rate with loss of vision was 3.5%. CONCLUSIONS: Ultraviolet-A light associated with riboflavin CXL is an efficient procedure to stabilize and improve progressive keratoconus. The results reinforce previous studies highlighting the efficacy and safety of the procedure. A large prospective randomized clinical trial is needed.

Journal Français d'Ophtalmologie, 2005

ABSTRACT Purpose Despite progress in mechanical microkeratomes used in refractive surgery, mechan... more ABSTRACT Purpose Despite progress in mechanical microkeratomes used in refractive surgery, mechanical complications during cutting of the cornea still occur. Cutting by laser could reduce these complications and to date, the femtosecond laser is the only potential candidate for this purpose. Our study reports preliminary results with a femtosecond microkeratome for cutting porcine corneas ex vivo. Methods We first examined the fundamental principles of the interaction between the femtosecond laser and the corneal stroma, including the volume of tissue lesions, the laser breakdown threshold of the stroma and the laser ablation selectivity. We then analyzed the quality of cutting corneal flaps with the laser, focusing on collateral tissue effects and the roughness of the interfaces observed both histologically and with scanning electron microscopy. Results The photoablative and photodisruptive effects were very similar with the femtosecond laser. This characteristic is specific to ultrashort impulsion photodisruptor lasers and allows for a very precise surgical procedure. The laser-induced breakdown threshold of porcine corneal stroma was found to be 0.55 J/cm2 Collateral tissue lesions were on the submicrometer level. The roughness of the stromal bed was optimal for postage stamp cutting, providing very many contiguous points of impact which were as spherical as possible. Conclusion Corneal photodisruption with a femtosecond laser is reproducible and extremely accurate. The optomechanical parameters involved with this technique require great technological skill and should be placed in experienced hands.

Journal Français d'Ophtalmologie, 2009

Cornée COMMUNICATIONS ORALES récidive inflammatoire a été notée en dehors de la zone greffée et a... more Cornée COMMUNICATIONS ORALES récidive inflammatoire a été notée en dehors de la zone greffée et a nécessité une adaptation du traitement d'entretien. Dans tous les cas, une amélioration ou une stabilisation de l'acuité visuelle a été notée. Discussion : Selon les indications, la greffe lamellaire cornéo-sclérales peut jouer un rôle architectonique (en cas de perforation avérée ou imminente), visuel (en cas d'astigmatisme important ou de perforation) ou immunologique (en limitant l'accès des médiateurs de l'inflammation sur la zone amincie). Conclusion : La greffe lamellaire cornéo-sclérale est une arme particulièrement efficace dans l'arsenal thérapeutique des amincissements cornéens périphériques dégénératifs ou immunologiques. Leur réalisation au cours des affections immunologiques ne se conçoit qu'après prise en charge de l'inflammation causale. 311 Greffes cornéennes endothéliales dans les dystrophies de Fuchs. Endothelial keratopasty in Fuchs endothelial corneal dystrophy.

Journal Français d'Ophtalmologie, 2013

The endothelio-descemetic interface (EDI) of a deep anterior lamellar keratoplasty (DALK) may bec... more The endothelio-descemetic interface (EDI) of a deep anterior lamellar keratoplasty (DALK) may become the locus of a neovascular proliferation. Bevacizumab (Avastin) is an antiangiogenic alternative available for curative treatment in deep corneal neovascularization. We report the case of a 49-year-old woman who had received two arcuate relaxing incisions for high astigmatism after DALK. She developed graft rejection associated with significant neovascular stromal invasion in the EDI of the graft-host interface. Two subconjunctival injections of bevacizumab 1 month apart as well as thermocauterization of the feeding vessel were necessary and effective. No recurrence has been observed after 2 years of follow-up. Corneal neovascularization can be a cause of DALK rejection. A combination of anti-antiangiogenic and physical methods may abort graft rejection and permanently restore graft function.

Journal Français d'Ophtalmologie, 2011

Investigative Opthalmology & Visual Science, 2012

American Journal of Ophthalmology, 2013

To develop a method for automatizing the detection of subclinical keratoconus based on a tree cla... more To develop a method for automatizing the detection of subclinical keratoconus based on a tree classification. DESIGN: Retrospective case-control study. METHODS: SETTING: University Hospital of Bordeaux. PARTICIPANTS: A total of 372 eyes of 197 patients were enrolled: 177 normal eyes of 95 subjects, 47 eyes of 47 patients with forme fruste keratoconus, and 148 eyes of 102 patients with keratoconus. OBSERVATION PROCEDURE: All eyes were imaged with a dual Scheimpflug analyzer. Fifty-five parameters derived from anterior and posterior corneal measurements were analyzed for each eye and a machine learning algorithm, the classification and regression tree, was used to classify the eyes into the 3 above-mentioned conditions. MAIN OUTCOME MEASURES: The performance of the machine learning algorithm for classifying eye conditions was evaluated, and the curvature, elevation, pachymetric, and wavefront parameters were analyzed in each group and compared. RESULTS: The discriminating rules generated with the automated decision tree classifier allowed for discrimination between normal and keratoconus with 100% sensitivity and 99.5% specificity, and between normal and forme fruste keratoconus with 93.6% sensitivity and 97.2% specificity. The algorithm selected as the most discriminant variables parameters related to posterior surface asymmetry and thickness spatial distribution. CONCLUSION: The machine learning classifier showed very good performance for discriminating between normal corneas and forme fruste keratoconus and provided a tool that is closer to an automated medical reasoning. This might help in the surgical decision before refractive surgery by providing a good sensitivity in detecting ectasia-susceptible corneas.

Cornea, 2012

We describe a case of a 52-year-old man in whom the appearance of an air bubble developed, trappe... more We describe a case of a 52-year-old man in whom the appearance of an air bubble developed, trapped within the Descemet membrane (DM), that occurred during a planned deep anterior lamellar keratoplasty using the "big bubble" technique. This situation can occur because Descemet membrane's anatomic structure can be opened by the gas dissection; this complication may result in unanticipated results during and after this type of surgery. Surgeons should be aware of this specific risk, so they will recognize it when it occurs. Optical coherence tomography (OCT) imaging and surgical management are presented.

American Journal of Ophthalmology, 2013

ABSTRACT Purpose: To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) u... more ABSTRACT Purpose: To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) using a modified “big-bubble” technique. Setting: Retrospective, interventional case series of eyes operated at a private hospital by a single surgeon (MB). Methods: Review of the medical records of all consecutive patients who underwent a modified DALK (small “big-bubble“ technique) between April 2012 to December 2013 at Villa Igea Hospital, Forli'. The standardized procedure included: 1) Partial thickness 9mm trephination; 2) Pneumatic dissection of the stroma; 3) Removal of about half thickness of the anterior stroma within the 9.0 mm incision; 4) Marking of the central 6.0 mm optical zone, perforation of the bubble and removal of the deep stroma with exposure of Descemet within the 6.0 mm zone; 5) Suturing of a donor lamella, 350-400 micron in thickness and 9.0 mm in diameter, obtained by means of microkeratome-assisted dissection. When pneumatic dissection failed, Descemet was dissected by hand over the same 6 mm central optical zone. Complete suture removal was performed 12 months postoperatively. Main outcome measures were best spectacle-corrected visual acuity (BSCVA), and endothelial cell density (ECD). Differences between groups were tested with a two-tailed Student’s t-test (p values <0.05 were considered significant). Results: Seventy-two eyes of 72 patients were included in the study. Indications for surgery were keratoconus (n=66, 91.6%), herpetic scars (n=2, 2.7%) and corneal dystrophy, exposure scar, corneal neoplastic infiltration, as well as scar secondary to trichiasis (n=1, %1.4 each). Pneumatic dissection succeeded in 32 (44.4%), and failed in 40 eyes (55.5%) patients. Stromal dissection was completed by hand in 39 of 40 eyes: microperforation occurred in 4 eyes (only in one patient after successful formation of a big bubble) but the procedure could be completed uneventfully. Macroperforation occurred in 1 eye and required conversion into mushroom keratoplasty. The average follow-up time was 7.4 months (range=3 to 18 months). The overall mean BSCVA was 0.6±0.2 and the mean ECD was 2060±355cells/mm2. In those eyes with all sutures out (n=15), BSCVA improved significantly from 0.52±0.14 before, to 0.74±0.16 (p<0.005) after complete suture removal. No significant difference in BSCVA (p = 0.9) could be found between eyes with successful and eyes with failed pneumatic dissection (0.58±0.25 versus 0.58±0.21). Postoperative complications included partial graft melting (n=2) requiring graft exchange in one case, stromal rejection (n=1) and high-degree astigmatism requiring relaxing incisions (n=1). Conclusions: The results of small “big-bubble” DALK exposing only the central 6 mm of Descemet’s membrane compare favorably to those of conventional big bubble surgery. However, the modification offers the refractive advantages of a 9.0 mm graft, the safety of performing a descemetic dissection only over a limited area, and the elimination of irregularities in the surgical wound, as both the graft edge and the recipient edge need no hand refinement. Complications are rare and if pneumatic dissection fails, the procedure can be completed by hand in almost all cases without affecting final visual acuity.

Journal of Refractive Surgery, 2013

To compare the discriminating ability of corneal elevation generated by a dual Scheimpflug analyz... more To compare the discriminating ability of corneal elevation generated by a dual Scheimpflug analyzer calculated with different reference surfaces for distinguishing normal corneas from those with keratoconus and subclinical keratoconus. A total of 391 eyes of 208 patients were prospectively enrolled in the study and divided into three groups: 167 eyes of 113 patients with keratoconus, 47 contralateral topographically normal eyes of patients with clinically evident keratoconus in the fellow eye, and 177 eyes of 95 refractive surgery candidates with normal corneas. All eyes were measured with a dual Scheimpflug analyzer (GALILEI Analyzer; Ziemer Ophthalmic Systems AG, Port, Switzerland). Maximum elevation values were recorded within the central 5-mm diameter in both anterior and posterior elevation maps. Discriminating ability of corneal elevation measurements obtained by best-fit toric and aspheric (BFTA) and best-fit sphere (BFS) reference surfaces were compared by receiver operator characteristic (ROC) curves. ROC curve analysis showed that corneal elevation measured by BFTA had a significantly better ability than with BFS for distinguishing normal corneas from those with keratoconus and forme fruste keratoconus (P = .01). Posterior elevation measured by BFTA had a significantly higher predictive accuracy for forme fruste keratoconus than anterior elevation with an area under ROC curves of 0.88 and 0.80, respectively (P = .01). The sensitivity and specificity achieved with the maximum posterior elevation for detecting keratoconus and forme fruste keratoconus were 99% and 99% for keratoconus and 82% and 80% for forme fruste keratoconus with the cut-off value at 16 and 13 μm, respectively. The ability to discriminate between normal cornea and forme fruste keratoconus with elevation parameters was significantly improved by using BFTA instead of BFS reference surface.

American Journal of Ophthalmology, 2013

ABSTRACT Purpose: To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) u... more ABSTRACT Purpose: To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) using a modified “big-bubble” technique. Setting: Retrospective, interventional case series of eyes operated at a private hospital by a single surgeon (MB). Methods: Review of the medical records of all consecutive patients who underwent a modified DALK (small “big-bubble“ technique) between April 2012 to December 2013 at Villa Igea Hospital, Forli'. The standardized procedure included: 1) Partial thickness 9mm trephination; 2) Pneumatic dissection of the stroma; 3) Removal of about half thickness of the anterior stroma within the 9.0 mm incision; 4) Marking of the central 6.0 mm optical zone, perforation of the bubble and removal of the deep stroma with exposure of Descemet within the 6.0 mm zone; 5) Suturing of a donor lamella, 350-400 micron in thickness and 9.0 mm in diameter, obtained by means of microkeratome-assisted dissection. When pneumatic dissection failed, Descemet was dissected by hand over the same 6 mm central optical zone. Complete suture removal was performed 12 months postoperatively. Main outcome measures were best spectacle-corrected visual acuity (BSCVA), and endothelial cell density (ECD). Differences between groups were tested with a two-tailed Student’s t-test (p values <0.05 were considered significant). Results: Seventy-two eyes of 72 patients were included in the study. Indications for surgery were keratoconus (n=66, 91.6%), herpetic scars (n=2, 2.7%) and corneal dystrophy, exposure scar, corneal neoplastic infiltration, as well as scar secondary to trichiasis (n=1, %1.4 each). Pneumatic dissection succeeded in 32 (44.4%), and failed in 40 eyes (55.5%) patients. Stromal dissection was completed by hand in 39 of 40 eyes: microperforation occurred in 4 eyes (only in one patient after successful formation of a big bubble) but the procedure could be completed uneventfully. Macroperforation occurred in 1 eye and required conversion into mushroom keratoplasty. The average follow-up time was 7.4 months (range=3 to 18 months). The overall mean BSCVA was 0.6±0.2 and the mean ECD was 2060±355cells/mm2. In those eyes with all sutures out (n=15), BSCVA improved significantly from 0.52±0.14 before, to 0.74±0.16 (p<0.005) after complete suture removal. No significant difference in BSCVA (p = 0.9) could be found between eyes with successful and eyes with failed pneumatic dissection (0.58±0.25 versus 0.58±0.21). Postoperative complications included partial graft melting (n=2) requiring graft exchange in one case, stromal rejection (n=1) and high-degree astigmatism requiring relaxing incisions (n=1). Conclusions: The results of small “big-bubble” DALK exposing only the central 6 mm of Descemet’s membrane compare favorably to those of conventional big bubble surgery. However, the modification offers the refractive advantages of a 9.0 mm graft, the safety of performing a descemetic dissection only over a limited area, and the elimination of irregularities in the surgical wound, as both the graft edge and the recipient edge need no hand refinement. Complications are rare and if pneumatic dissection fails, the procedure can be completed by hand in almost all cases without affecting final visual acuity.