Three-dimensional Printing of Optical Lenses and Ophthalmic Surgery: Challenges and Perspectives.

PURPOSE: To determine whether the historical Ridley lens could be reproduced with current three-dimensional lens printing technology. METHODS: A reproduction of the Ridley lens was printed using the Printoptical Technology (LUXeXceL Group BV, Kruiningen, Netherlands). Photographs and electron microscopy images were taken. Dimensions, weight, anterior and posterior surface radius of curvature, optical transmission, back optical power, and surface analysis using interferometry were obtained. RESULTS: The printed lens was 8.10 ± 0.01 mm in diameter, 2.50 ± 0.01 mm thick, and weighed 117 mg. The anterior radius of curvature was 14.63 ± 0.69 mm and the posterior radius of curvature was 10.88 ± 0.22 mm. The back focal length in air was 14.1 ± 0.4 mm. An average 75% transmission in the visible spectrum (400 to 700 nm) was achieved. Surface analysis showed significant surface roughness. CONCLUSIONS: The printed reproduction of the Ridley lens was far from current clinical standards, but had the properties of a biconvex lens.

Reliability of cone counts using an adaptive optics retinal camera.

BACKGROUND: To assess the reproducibility and repeatability of cone imaging in healthy human eyes, using the RTx-1 Adaptive Optics Retinal Camera and its proprietary cone-counting software. DESIGN: Single-centre, prospective study. PARTICIPANTS: Ten healthy adults. METHODS: Macular cones were imaged. Intrasession repeatability was assessed by comparing 10 consecutive acquisitions obtained by the same operator from each subject. For the intersession study, each subject was imaged five consecutive days. Interoperator reproducibility was also evaluated by comparing the images obtained from 10 different subjects by two independent operators. Finally, intergrader agreement was evaluated by comparing the cone counts measured by two masked graders. MAIN OUTCOME MEASURES: Mean cone density (cells/mm(2) ), spacing between cells (µm) and percentage of cones with six neighbours calculated on Voronoi diagrams were measured. Correlation coefficients, intraclass correlation coefficients, and coefficients of variation were calculated. RESULTS: Correlation coefficient and intraclass correlation coefficient were respectively 0.81 and 0.96 between operators, and 0.97 and 0.98 between the two graders. The intrasession and intersession coefficients of variation were under 7%. The percentage of cells with six neighbours and the spacing between cones varied in the same proportion (coefficients of variation ranged from 1.66 to 10.05%). CONCLUSIONS: Overall, the test-retest variability of RTx-1 and its software was good in normal human eyes. Further studies in the normal clinical setting are mandatory.

Choroidal thickness measurement in children using optical coherence tomography.

PURPOSE: To measure choroidal thickness (CT) in children of various ages by using spectral optical coherence tomography with enhanced depth imaging and to investigate the association between subfoveal CT and ocular axial length, age, gender, weight, and height in children. METHODS: Healthy children were prospectively included between May and August 2012. Optical coherence tomography with the enhanced depth imaging system (Spectralis, Heidelberg, Germany) was used for choroidal imaging at nine defined points of the macula of both eyes. Axial length was measured using IOLMaster (Carl Zeiss Meditec, Dublin, CA). Height, weight, and refraction were recorded. Interobserver agreement in readings was also assessed by the Bland-Altman Method. RESULTS: Three hundred and forty-eight eyes from 174 children aged 3.5 years to 14.9 years were imaged. The mean subfoveal CT in right eyes was 341.96 ± 74.7 µm. Choroidal thickness increased with age (r = 0.24, P = 0.017), height, and weight but not with gender (P > 0.05). It was also inversely correlated to the axial length (r = 0.24, P = 0.001). The nasal choroid appeared thinner than in the temporal area (analysis of variance, P < 0.0001). CONCLUSION: In children, CT increases with age and is inversely correlated to axial length. There is a significant variation of CT between children of the same age.

Sutureless intrascleral intraocular lens implantation after ocular trauma.

PURPOSE: To report the results and safety of sutureless intrascleral haptic fixation in traumatized eyes and to compare this procedure with retropupillary iris-claw intraocular lens (IOL) fixation. SETTING: University Hospital of Strasbourg, Strasbourg, France. DESIGN: Interventional case series. METHODS: Patients with traumatic cataract and severely damaged capsular bags were divided into 2 groups (Group 1: intrascleral IOLs [Acrysof MN60 AC]; Group 2: retropupillary iris-claw IOLs [Verisyse]). The main outcome was the final visual acuity. The surgically induced astigmatism (SIA) was calculated by the vectorial method. RESULTS: Twenty-six eyes of 23 patients were studied, 8 eyes in Group 1 and 18 eyes in Group 2. The mean follow-up was 14 months. There was no difference in corrected distance visual acuity (CDVA) at the time of the surgery (P>.05). The mean CDVA (logMAR) was 1.68 ± 1.15 (SD) preoperatively and 0.55 ± 0.9 postoperatively in Group 1 (P = .03) and 1.11 ± 1.13 and 0.32 ± 0.47, respectively, in Group 2 (P = .003). The final CDVA was not different between groups (P>.05). The mean SIA was 1.91 ± 1.66 diopters (D) in Group 1 and 2.74 ± 1.92 D in Group 2 (P>.05). No intraoperative complications occurred in Group 2; a haptic broke in Group 1. Macular edema occurred in both groups. CONCLUSIONS: Sutureless intrascleral IOLs corrected posttraumatic aphakia. The SIA was comparable between groups. This procedure should be considered after trauma when other implantation techniques are not possible.

Videokeratographic anomalies in familial keratoconus.

OBJECTIVE: To analyze videokeratography of relatives of established familial keratoconus (FK) patients to detect low-expressivity keratoconus and improve the diagnosis criteria of forme fruste keratoconus. DESIGN: Multicenter case-control study. PARTICIPANTS: Twenty-three families with 55 clinical keratoconus patients, 89 first-degree relatives, 43 other relatives, and a control group of 130 subjects. METHODS: Videokeratography was performed on both eyes of patients after clinical examination, and corneal maps were analyzed. Statistical comparisons were conducted between first-degree and other relatives and a control population. MAIN OUTCOME MEASURES: Qualitative (using a 0.5-diopter [D] increment scale) and quantitative analyses of videokeratographs. RESULTS: Two corneal patterns were overrepresented in the relatives of FK patients: the J and inverted-J form patterns. Results of the quantitative analysis of these suspect patterns showed that the inferior - superior values (reflecting the inferior - superior dioptric asymmetry) were close to 0.8 D and the Srax (relative skewing of the steepest radial axes) was superior to 21 degrees. CONCLUSION: Our study using topography in clearly established genetic keratoconus families allowed us to detect suspect topographical patterns and brings new data to the difficult task of diagnosing forme fruste keratoconus.