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3D printing has a great and surprising number of uses in the field of medicine. Some of these uses are nowadays on a trial phase but others are becoming more common as 3D printing of prosthesis and implants. This study uses the most advanced technology in topography to get a 3D image of the anterior surface of the eye and explores how to use this information to get a scleral cover shell prosthesis by 3D printing techniques. The reliable results of the study could lead the way to new ways of fitting scleral cover shell prosthesis. Advance topography and 3D printing simplify the process and benefit patients avoiding the step of getting an ocular mold and reducing the number of visits to the eye care professional. [ABSTRACT FROM AUTHOR]

Background: Contact lenses can cause complications in 2/3 of the total population, but in most cases, they are mild and easy to manage. However, most of the studies are short-term. The aim of the study was to analyze the publications on the long-term effects of contact lens wear to understand the current research landscape through the analysis of dating networks as well as determining the different research areas and the most cited publications.Methods: The Web of Science database was used to perform the publication search, looking for the terms "Long-term" AND "contact lens wear" within the period between 1977 and January 2021. The CitNetExplorer and CiteSpace software were then used to conduct the publication analysis. To obtain the graphics, the VOSviewer software was used.Results: A total of 721 publications were found with 2999 citations generated within the network. The year 2010 was singled out as a "key year", considering the number of publications that emerged in that year and increase in adaptations of contact lens worldwide. The most widely cited publication was "Effects of long-term extended contact lens wear on the human cornea", an article by Holden et al., which was published in 1985. By using the clustering function, we were able to establish three clusters that encompassed the different research areas within this field: morphological changes, the loss of corneal sensitivity, tear film characteristics and longitudinal changes in ocular physiology.Conclusions: The main research topic in this field focuses on the morphological changes that take place in the corneal endothelial cell layer. [ABSTRACT FROM AUTHOR]

Purpose To evaluate how soft lens power affects rigid gas-permeable (RGP) lens power and visual acuity (VA) in piggyback fittings for keratoconus. Methods Sixteen keratoconus subjects (30 eyes) were included in the study. Piggyback contact lens fittings combining Senofilcon-A soft lenses of −6.00, −3.00, +3.00 and +6.00 D with Rose K2 RGP contact lenses were performed. Corneal topography was taken on the naked eye and over each soft contact lens before fitting RGP lenses. Mean central keratometry, over-refraction, RGP back optic zone radius (BOZR) and estimated final power as well as VA were recorded and analyzed. Results In comparison to the naked eye, the mean central keratometry flattened with both negative lens powers ( p < 0.05 in all cases), did not change with the +3.00 soft lens power ( p = 1.0); and steepened with the +6.00 soft lens power ( p = 0.02). Rigid gas-permeable over-refraction did not change significantly between different soft lens powers (all p > 0.05). RGP's BOZR decreased significantly with both positive in comparison with both negative soft lens powers (all p < 0.001), but no significant differences were found among negative- or positive-powers separately (both p > 0.05). Estimated RGP's final power increased significantly with positive in comparison with negative lens powers (all p < 0.001), but no significant differences were found among negative or positive lens powers separately (both p > 0.05). Visual acuity did not change significantly between the different soft lens powers assessed (all p > 0.05). Conclusion The use of negative-powered soft lenses in piggyback fitting reduces RGP lens power without impacting VA in keratoconus subjects. [ABSTRACT FROM AUTHOR]