Damien Gatinel

Topographic and tomographic properties of forme fruste keratoconus corneas.

PURPOSE To investigate the efficacy of topography and tomography indices combined in discriminant functions to detect mild ectatic corneas. METHODS The authors retrospectively reviewed the data of 143 eyes separated into three groups by the Corneal Navigator OPD scanning system (Nidek, Gamagori, Japan): normal (N; LASIK surgery with a 2-year follow-up; n = 72), forme fruste keratoconus (N topography with contralateral KC; FFKC; n = 40), and KC (n = 31). Topography and tomography indices, corneal thickness spatial profile (CTSP), and anterior and posterior curvature spatial profiles were obtained with the Orbscan IIz (Bausch & Lomb Surgical, Rochester, NY). The percentage of thickness increase (PTI) from the thinnest point to the periphery, the percentage of variation of anterior (PVAK), and posterior curvature were calculated and compared by Kruskal-Wallis test. The usefulness of these data to discriminate among the three groups was assessed by receiver operating characteristic (ROC) curve analysis. RESULTS Posterior elevation of the thinnest point (TP), all positions of CTSP, PTI for all distances from the TP, and PVAK from a 5- to 7-mm distance from the TP were significantly different in the FFKC compared with the N group. The discriminant functions between the FFKC and the N groups and between the KC and the N groups reached an area under the ROC curve of 0.98 and 0.99, respectively. PTI indices and maximum posterior central elevation were the most important contributors to the discriminant function. CONCLUSIONS Indices generated from corneal thickness and curvature measurements over the entire cornea centered on the TP can identify very mild forms of ectasia undetected by a Placido-based neural network program.

Detection of static cyclotorsion and compensation for dynamic cyclotorsion in laser in situ keratomileusis

PURPOSE: To evaluate the degree of static and dynamic cyclotorsion using a rotational eye tracker in laser in situ keratomileusis (LASIK) to correct myopic astigmatism. SETTING: Rothschild Foundation, Paris, France. DESIGN: Cohort study. METHODS: Laser in situ keratomileusis with active iris registration using a Zyoptix 100 Hz excimer laser with Advanced Control Eyetracking was performed in eyes with myopic astigmatism. In all cases, iris registration was used to evaluate the degree of static cyclotorsion preoperatively and the degree of dynamic cyclotorsion and intraoperatively. The direction, mean values, and ranges of static and dynamic cyclotorsion were recorded. The amplitude of intraoperative cyclotorsion was reported. RESULTS: The study included 74 consecutive eyes (38 patients). The direction of cyclotorsion was not statistically significant. The mean static cyclotorsion was 3.08 degrees ± 2.68 (SD) (range −7.0 to 14.0 degrees) and the mean dynamic cyclotorsion, 3.39 ± 2.94 degrees (range −10.3 to 13.5 degrees). During photoablation, the mean amplitude of cyclotorsion was 2.69 ± 1.63 degrees (range 0.0 to 9.2 degrees). The magnitude of dynamic cyclotorsion was less than 5 degrees in 66% of eyes, 5 degrees or more in 34% of eyes, and 10 degrees or more in 4% of eyes. CONCLUSIONS: Static and dynamic cyclotorsion was detected with a dynamic eye tracker in eyes having LASIK. Rotational movements were mainly static but had significant amplitude during photoablation. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Aqueous flare induced by heparin-surface-modified poly(methyl methacrylate) and acrylic lenses implanted through the same-size incision in patients with diabetes

Purpose: To compare the degree of blood–aqueous barrier (BAB) breakdown in eyes of diabetic patients after phacoemulsification and implantation of heparin‐surface‐modified poly(methyl methacrylate) (PMMA) or soft hydrophobic acrylic intraocular lenses (IOLs) performed using the same technique with the same incision size to determine the influence of the IOLs on postoperative inflammation independent of other surgical factors. Settings: Department of Ophthalmology, University of Paris XIII, Bobigny, France. Methods: In a prospective study, 44 eyes of 31 diabetic patients with or without mild to moderate diabetic retinopathy were randomly assigned to receive an HSM PMMA IOL (22 eyes) or a soft hydrophobic acrylic IOL (22 eyes) after standardized phacoemulsification surgery. Both types of IOLs had a 6.0 mm optic, were inserted unfolded, and were placed in the bag through a calibered 6.0 mm superior scleral incision. Anterior chamber flare was measured preoperatively and 1, 7, 30, and 240 days postoperatively using the Kowa 500 laser flare meter. Results: The mean flare value was higher on the first postoperative day in both groups. There were no statistically significant between‐group differences in flare scores or clinical parameters preoperatively or at any postoperative visit. Conclusions: No significant difference was observed in inflammation between eyes having HSM PMMA IOL implantation or those having soft hydrophobic acrylic IOL implantation through the same‐size incision. This indicates that hydrophobic acrylic and HSM PMMA materials induce the same degree of BAB breakdown after phacoemulsification in eyes of diabetic patients.

Retrospective testing of a new method for detecting ectasia-susceptible corneas.

Keratectasia is a rare but severe complication of laser in situ keratomileusis (LASIK). As the number of patients who have refractive surgery increases, more cases of ectasia are being recognized. The best predictor for the development of ectasia after LASIK is the presence of an overlooked ectatic disorder preoperatively, in which case LASIK is an aggravating factor for the acceleration of the ectatic process. The recent case report by Hodge et al. highlights a patient who developed unilateral corneal ectasia 6 years after unilateral LASIK despite normal preoperative parameters and good postoperative stromal bed thickness. We recently described a new method for detecting a very early form of keratoconus (ectasiasusceptible corneas) that is undetected by Placidobased neural network. In that article, we described a discriminant function based on elevation topography and tomography indices that could be used to identify forme fruste keratoconus with 93% sensitivity and 92% specificity. Themean output values of the discriminant function were 0.55 G 0.78 in the normal group and 3.55G 1.32 in the forme fruste keratoconus group, with 1.55 selected as the cutoff value for the best discrimination.