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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]

Keratoconus is a bilateral and asymmetric disease which results in progressive thinning and steeping of the cornea leading to irregular astigmatism and decreased visual acuity. Traditionally, the condition has been described as a noninflammatory disease; however, more recently it has been associated with ocular inflammation. Keratoconus normally develops in the second and third decades of life and progresses until the fourth decade. The condition affects all ethnicities and both sexes. The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 cases per 100,000 persons/year, respectively, with highest rates typically occurring in 20- to 30-year-olds and Middle Eastern and Asian ethnicities. Progressive stromal thinning, rupture of the anterior limiting membrane, and subsequent ectasia of the central/paracentral cornea are the most commonly observed histopathological findings. A family history of keratoconus, eye rubbing, eczema, asthma, and allergy are risk factors for developing keratoconus. Detecting keratoconus in its earliest stages remains a challenge. Corneal topography is the primary diagnostic tool for keratoconus detection. In incipient cases, however, the use of a single parameter to diagnose keratoconus is insufficient, and in addition to corneal topography, corneal pachymetry and higher order aberration data are now commonly used. Keratoconus severity and progression may be classified based on morphological features and disease evolution, ocular signs, and index-based systems. Keratoconus treatment varies depending on disease severity and progression. Mild cases are typically treated with spectacles, moderate cases with contact lenses, while severe cases that cannot be managed with scleral contact lenses may require corneal surgery. Mild to moderate cases of progressive keratoconus may also be treated surgically, most commonly with corneal cross-linking. This article provides an updated review on the definition, epidemiology, histopathology, aetiology and pathogenesis, clinical features, detection, classification, and management and treatment strategies for keratoconus. [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]

Purpose: To assess long-term intraocular straylight changes induced by corneal refractive therapy (CRT) and to determine whether these changes persist after cessation of CRT lens wear. Methods: A single-center, prospective, longitudinal study was performed in 22 subjects (group 1) undergoing overnight corneal refractive therapy for 1 year. Ten right eyes of 10 subjects (group 2) with emmetropia served as controls. In each subject, high contrast visual acuity (HCVA), manifest refraction and intraocular straylight were determined at several time points during treatment and 1 month after discontinuing treatment. Straylight was measured using the van den Berg straylight meter (third generation). EDTRS charts (logMAR units) were used to assess HCVA. For both groups, only data for the right eyes were analyzed. Results: Straylight (mean±standard deviation) significantly fell from baseline (0.98±0.13) to values recorded after 1 month (0.88±0.13, p =0.011), 3 months (0.88±0.13, p =0.004), 6 months (0.88±0.13, p =0.000) and 12 months (0.76±0.12, p =0.003) of treatment. One month after discontinuing CRT lens wear, straylight was still significantly lower than baseline (0.89±0.13, p =0.003). No correlations were observed between intraocular straylight and HCVA. Conclusions: Good refractive outcomes and reductions in straylight were observed in response to corneal refractive therapy for myopia. The reduction in straylight observed after discontinuing CRT warrents further investigation. [ABSTRACT FROM AUTHOR]