Long-term changes in corneal structure and tear inflammatory mediators after orthokeratology and LASIK

PURPOSE: To monitor changes in corneal structure and level of inflammatory mediators in tears of myopic patients following orthokeratology (OK) and laser in situ keratomileusis (LASIK). METHODS: Sixty-two myopic subjects were analyzed in this prospective study. Thirty-two had worn Paragon CRT contact lenses and 30 underwent standard LASIK. Thirty-two control subjects were also recruited. Pachometry and corneal topography were performed 12 months after both interventions. Tears were collected and assayed using ELISA for IL-6, IL-8, matrix metalloproteinase-9 (MMP-9), and epidermal growth factor (EGF). RESULTS: Corneal power decreased in the central area and increased in the paracentral area. Simultaneously, there was a central corneal thinning with mid-peripheral thickening for OK. No changes were observed for LASIK. In comparison with controls, IL-6, IL-8, MMP-9, and EGF levels were increased significantly for OK (P < 0.01). Only MMP-9 (P < 0.01) and EGF (P < 0.01) were increased for LASIK. Pro-inflammatory response was found to be associated with the degree of myopia in the OK group. The MMP-9 and EGF upregulation was linked to the presence of iron deposition in both groups, whereas increased levels of EGF were connected with the presence of myopic regression after LASIK. CONCLUSIONS: Both interventions involved important tissue reshaping. The physical presence of a reverse geometry contact lens caused certain markers to change significantly in comparison with no lens wear or LASIK in the long-term response. MMP-9 was significantly higher in tears of subjects presenting iron deposition after OK or LASIK, and EGF levels seemed to play an important role in postoperative refractive outcomes after LASIK.Supported by National Grant PI081380 from Instituto de Salud Carlos III, Spain, awarded to the Ocular Surface and Contact Lens Research Group GI-1750

Pigmented corneal ring associated with orthokeratology in caucasians : case reports

BACKGROUND: The aim was to report the appearance of a pigmented ring in both eyes of two patients undergoing overnight orthokeratology. METHODS: Two Caucasian patients, one male and one female, were fitted with orthokeratology lenses to correct myopia between -2.00 and -2.50 DS with Paragon corneal refractive therapy lenses worn overnight. Treatment was successful in both patients achieving uncorrected vision of 6/6 or better monocularly under high (100 per cent) and low (10 per cent) contrast conditions. RESULTS: At the six-month visit both patients presented with pigmented rings under slitlamp examination in both eyes. The location of the ring was consistent with the corneal area being flattened for myopic correction. Clinical examination was otherwise normal. CONCLUSIONS: Despite being initially reported in Asian patients from Hong Kong, a pigmented ring related to orthokeratology treatment is also present in Caucasian patients, reducing the potential role of an ethnic link. Further large-scale studies need to be done to estimate the actual incidence of this condition and the potential implications for corneal health

Corneal biomechanical properties in different ocular conditions and new measurement techniques

Several refractive and therapeutic treatments as well as several ocular or systemic diseases might induce changes in the mechanical resistance of the cornea. Furthermore, intraocular pressure measurement, one of the most used clinical tools, is also highly dependent on this characteristic. Corneal biomechanical properties can be measured now in the clinical setting with different instruments. In the present work, we review the potential role of the biomechanical properties of the cornea in different fields of ophthalmology and visual science in light of the definitions of the fundamental properties of matter and the results obtained from the different instruments available. The body of literature published so far provides an insight into how the corneal mechanical properties change in different sight-threatening ocular conditions and after different surgical procedures. The future in this field is very promising with several new technologies being applied to the analysis of the corneal biomechanical properties

Current approaches to soft contact lens handling training - Global perspectives

Purpose All neophyte contact lens wearers require training on how to handle contact lenses. Currently, almost no published information exists describing the most common approaches used by those involved in such training in soft contact lens wearers. This study aimed to gather information on the approaches taken by those conducting this training worldwide. Methods An online survey was created in English and translated to Spanish and distributed internationally via social media, conference attendees, and professional contacts. The anonymous survey included information on workplace setting of respondents, information about the typical approaches used for application and removal of soft contact lenses, length of the appointment, and success rate with their approach. Survey responses were received between May 2021 and April 2022. Results A total of 511 individuals completed the survey and responses were received from 31 countries with 48.7% from the UK. The most common approach taught for application was to have the patient hold the upper eyelashes (84.7%) and to hold the lower eyelid with the same hand as the lens (89.4%). Lenses were applied directly to the cornea by 57.7% of the respondents. The most common approach taught for lens removal was to drag the lens inferiorly from the cornea prior to removal (49.3%). Most respondents did not use videos to aid the teaching appointment (62.0%); however, they felt that their approach was successful in most cases (90). Application and removal training sessions lasted a median of 30 min and contact lenses were typically dispensed after the instructor witnessing successful application and removal three times. Conclusion Various methods are adopted globally for training of application and removal of soft contact lenses, with many advising a patient-specific approach is required for success. The results of this survey provide novel insights into soft contact lens handling training in clinical practice

BCLA CLEAR Presbyopia:Epidemiology and impact

The global all-ages prevalence of epidemiologically-measured 'functional' presbyopia was estimated at 24.9% in 2015, affecting 1.8 billion people. This prevalence was projected to stabilise at 24.1% in 2030 due to increasing myopia, but to affect more people (2.1 billion) due to population dynamics. Factors affecting the prevalence of presbyopia include age, geographic location, urban versus rural location, sex, and, to a lesser extent, socioeconomic status, literacy and education, health literacy and inequality. Risk factors for early onset of presbyopia included environmental factors, nutrition, near demands, refractive error, accommodative dysfunction, medications, certain health conditions and sleep. Presbyopia was found to impact on quality-of-life, in particular quality of vision, labour force participation, work productivity and financial burden, mental health, social wellbeing and physical health. Current understanding makes it clear that presbyopia is a very common age-related condition that has significant impacts on both patient-reported outcome measures and economics. However, there are complexities in defining presbyopia for epidemiological and impact studies. Standardisation of definitions will assist future synthesis, pattern analysis and sense-making between studies

Improvement of Retinal Images Affected by Cataracts

Eye fundus images are used in clinical diagnosis for the detection and assessment of retinal disorders. When retinal images are degraded by scattering due to opacities of the eye tissues, the precise detection of abnormalities is complicated depending on the grading of the opacity. This paper presents a concept proof study on the use of the contrast limited adaptive histogram equalization (CLAHE) technique for better visualization of eye fundus images for different levels of blurring due to different stages of cataracts. Processing is performed in three different color spaces: RGB, CIELAB and HSV, with the aim of finding which one better enhances the missed diagnostic features due to blur. The experimental results show that some fundus features not observable by naked eye can be detected in some of the space color processed with the proposed method. In this work, we also develop and provide an online image process, which allows clinicians to tune the default parameters of the algorithm for a better visualization of the characteristics of fundus images. It also allows the choice of a region of interest (ROI) within the images that provide better visualization of some features than those enhanced by the processing of the full picture

Modern scleral contact lenses: a review

Scleral contact lenses (ScCL) have gained renewed interest during the last decade. Originally, they wereprimarily used for severely compromised eyes. Corneal ectasia and exposure conditions were the primaryindications. However, the indication range of ScCL in contact lens practices seems to be expanding, andit now increasingly includes less severe and even non-compromised eyes, too.All lenses that partly or entirely rest on the sclera are included under the name ScCL in this paper;although the Scleral Lens Education Society recommends further classification. When a lens partly restson the cornea (centrally or peripherally) and partly on the sclera, it is called a corneo-scleral lens. A lensthat rests entirely on the sclera is classified as a scleral lens (up to 25 mm in diameter maximum). Whenthere is full bearing on the sclera, further distinctions of the scleral lens group include mini-scleral andlarge-scleral lenses.This manuscript presents a review of the current applications of different ScCL (all types), their fittingmethods, and their clinical outcomes including potential adverse events. Adverse events with these lensesare rare, but the clinician needs to be aware of them to avoid further damage in eyes that often are alreadycompromised. The use of scleral lenses for non-pathological eyes is discussed in this pape

Current approaches to soft contact lens handling training – Global perspectives

Purpose: All neophyte contact lens wearers require training on how to handle contact lenses. Currently, almost no published information exists describing the most common approaches used by those involved in such training in soft contact lens wearers. This study aimed to gather information on the approaches taken by those conducting this training worldwide. Methods: An online survey was created in English and translated to Spanish and distributed internationally via social media, conference attendees, and professional contacts. The anonymous survey included information on workplace setting of respondents, information about the typical approaches used for application and removal of soft contact lenses, length of the appointment, and success rate with their approach. Survey responses were received between May 2021 and April 2022. Results: A total of 511 individuals completed the survey and responses were received from 31 countries with 48.7% from the UK. The most common approach taught for application was to have the patient hold the upper eyelashes (84.7%) and to hold the lower eyelid with the same hand as the lens (89.4%). Lenses were applied directly to the cornea by 57.7% of the respondents. The most common approach taught for lens removal was to drag the lens inferiorly from the cornea prior to removal (49.3%). Most respondents did not use videos to aid the teaching appointment (62.0%); however, they felt that their approach was successful in most cases (90). Application and removal training sessions lasted a median of 30 min and contact lenses were typically dispensed after the instructor witnessing successful application and removal three times. Conclusion: Various methods are adopted globally for training of application and removal of soft contact lenses, with many advising a patient-specific approach is required for success. The results of this survey provide novel insights into soft contact lens handling training in clinical practice.</p