Anti-VEGF Agents for the Treatment of Pigment Epithelial Detachments Associated With Neovascular Age-related Macular Degeneration: An Evidence-based Approach

Editorial, No abstrac

Anti-VEGF Agents for the Treatment of Pigment Epithelial Detachments Associated With Neovascular Age-related Macular Degeneration: An Evidence-based Approach

Editorial, No abstrac

Keratoconus: is it a Non-inflammatory Disease?

Editorial/No abstrac

Keratoconus: is it a Non-inflammatory Disease?

Editorial/No abstrac

Late-Onset Anterior Dislocation of a Posterior Chamber Intraocular Lens in a Patient with Pseudoexfoliation Syndrome

Here, we report on a patient with pseudoexfoliation syndrome who developed acute angle-closure glaucoma with a marked myopic shift due to anterior dislocation of the posterior chamber intraocular lens almost 16 months after an uneventful phacoemulsification. Examination with a Scheimpflug camera was extremely useful in confirming the diagnosis. This is the fist case of late-onset angle-closure glaucoma with a significant myopic shift due to anterior dislocation of the posterior chamber intraocular lens, which resulted in a permanent alteration of the postoperative target refraction

Validation of Neural Network Predictions for the Outcome of Refractive Surgery for Myopia

Background: Refractive surgery (RS) for myopia has made a very big progress regarding its safety and predictability of the outcome. Still, a small percentage of operations require retreatment. Therefore, both legally and ethically, patients should be informed that sometimes a corrective RS may be required. We addressed this issue using Neural Networks (NN) in RS for myopia. This was a recently developed validation study of a NN.  Methods: We anonymously searched the Ophthalmica Institute of Ophthalmology and Microsurgery database for patients who underwent RS with PRK, LASEK, Epi-LASIK or LASIK between 2010 and 2018. We used a total of 13 factors related to RS. Data was divided into four sets of successful RS outcomes used for training the NN, successful RS outcomes used for testing the NN performance, RS outcomes that required retreatment used for training the NN and RS outcomes that required retreatment used for testing the NN performance. We created eight independent Learning Vector Quantization (LVQ) networks, each one responding to a specific query with 0 (for the retreat class) or 1 (for the correct class). The results of the 8 LVQs were then averaged so we could obtain a best estimate of the NN performance. Finally, a voting procedure was used to reach to a conclusion. Results: There was a statistically significant agreement (Cohen’s Kappa = 0.7658) between the predicted and the actual results regarding the need for retreatment. Our predictions had good sensitivity (0.8836) and specificity (0.9186). Conclusion: We validated our previously published results and confirmed our expectations for the NN we developed. Our results allow us to be optimistic about the future of NNs in predicting the outcome and, eventually, in planning RS

Simulation of Corneal imaging properties for near objects

Purpose Using raytracing simulation to study the effect of corneal imaging metrics for different aperture sizes as a function of object distances with different schematic model eyes. Methods This raytracing simulation determined the best focus (with the least root‐mean‐square (rms) ray scatter) and the best wavefront focus (with least rms wavefront error) for four schematic model eyes (Liou‐Brennan (LBME), Atchison (ATCHME), Gullstrand (GULLME) and Navarro (NAVME)) with 4 aperture sizes (2–5 mm) and 30 object distances in a logscale from 10 cm to 10 m plus infinity. For each configuration, 10,000 rays were traced through the cornea, and the aperture stop was located at the lens front apex plane as described in the model eyes. The wavefront was decomposed into Zernike components to extract the spherical aberration term. Results The focal distance with respect to the corneal front apex increases from around 31 mm for objects at infinity to around 40 mm for objects at 10 cm. The best (wavefront) focus was systematically closer to the cornea compared with the paraxial focus, and the overestimation of focal length with the paraxial focus was larger for large aperture sizes and small object distances. The rms ray scatter and wavefront error were both systematically larger with large aperture and small object sizes. At best focus the rms wavefront error was systematically larger, and the rms ray scatter was systematically smaller compared to the best wavefront focus. Spherical aberration varied more with GULLME than with LBME or NAVME, and increased strongly at smaller object distances. Conclusions The imaging properties of the cornea, especially spherical aberration, increase strongly as the object distance decreases. This effect should be considered, especially when considering aberration correcting lenses for near vision such as multifocal or enhanced depth of focus lenses