Surgical outcomes of isolated lens coloboma with or without cataract among young adults

Objective: To evaluate the visual and refractive outcomes after phacoemulsification surgery in eyes with isolated lens coloboma. Design: Prospective, consecutive case series. Participants: Eighteen eyes with isolated lens coloboma of 13 patients were included in the study. Mean patient age was 13.9 ± 6.5 years. Methods: Patients underwent phacoemulsification surgery, with combined implantation of capsular tension ring (CTR) and intraocular lens. In colobomas of less than 120°, a CTR was used, whereas in colobomas of more than 120°, a Cionni-modified single eyelet CTR was used to achieve better capsular centration. The main outcome measures were uncorrected distance visual acuity, corrected distance visual acuity, refraction, and keratometry. Results: Mean logMAR uncorrected distance visual acuity and corrected distance visual acuity improved significantly from 1.53 ± 0.35 and 1.02 ± 0.47 before surgery to 0.67 ± 0.51 and 0.52 ± 0.49 at the last visit of the follow-up (p < 0.001). Mean refractive cylinder and spherical equivalent decreased significantly from –6.73 ± 1.73 and –6.72 ± 4.07 D preoperatively to –1.40 ± 1.39 and –0.83 ± 1.31 D at the end of the follow-up (p = 0.001 and p = 0.01, respectively). Mean keratometric astigmatism at preoperative and postoperative visits were 1.58 ± 0.97 and 1.65 ± 0.94 D, respectively (p = 0.70). Conclusions: Phacoemulsification with CTR and intraocular lens implantation is an effective and safe option for providing a refractive correction and a significant visual improvement in eyes with isolated lens coloboma.

Identical Location Transmission Electron Microscopy Imaging of Site-Selective Pt Nanocatalysts: Electrochemical Activation and Surface Disordering

We have employed identical location transmission electron microscopy (IL-TEM) to study changes in the shape and morphology of faceted Pt nanoparticles as a result of electrochemical cycling; a procedure typically employed for activating platinum surfaces. We find that the shape and morphology of the as-prepared hexagonal nanoparticles are rapidly degraded as a result of potential cycling up to +1.3 V. As few as 25 potential cycles are sufficient to cause significant degradation, and after about 500–1000 cycles the particles are dramatically degraded. We also see clear evidence of particle migration during potential cycling. These finding suggest that great care must be exercised in the use and study of shaped Pt nanoparticles (and related systems) as electrocatlysts, especially for the oxygen reduction reaction where high positive potentials are typically employed.