Corneal erosions in contact lens wear

Nutrient Supplementation Improves Contact Lens-Induced Corneal Cell Damage Based on a SIRC Cellular Model

OBJECTIVES

The long-term use of contact lenses may damage the structure of the ocular surface and cause metabolic disorders in corneal cells. Vitamins and amino acids help maintain the physiological function of the eye. In the present study, the effects of nutrient (vitamin and amino acid) supplementation on corneal cell repair after contact lens-induced damage was investigated.

METHODS

High-performance liquid chromatography was used to quantify the nutrient contents of minimum essential medium, and the MTT assay was used to measure the viability of corneal cells. A Statens Seruminstitut rabbit cornea cellular model was established to simulate contact lens-induced keratopathy and investigate the effects of vitamin and amino acid supplementations on corneal cell repair.

RESULTS

The high water content lens group (78%) has a cell viability as high as 83.3%, whereas the cell viability of the low water content lens group (38%) is only 51.6%. The 32.0% difference between the two groups confirms the correlation between water content of lens and corneal viability.

CONCLUSIONS

Vitamin B2, vitamin B12, asparagine, and taurine supplementation may help improve contact lens-induced damage.

Role of Different Types of Contact Lenses in Epithelial Thickness

OBJECTIVE

To evaluate the potential role of different types of contact lenses, such as soft (SCL), hard (HCL), and mini scleral (SCCL), in corneal epithelial thickness with anterior segment optical coherence tomography (AS-OCT).

METHODS

In this cross-sectional study, patients who used contact lens at recent 6 months were recruited consecutively from September 2019 to October 2019, and the epithelial thicknesses of the cornea were obtained by AS-OCT and compared with control subjects who did not use contact lens.

RESULTS

In total, 184 eyes (115 subjects) were included; of them, 75 eyes were keratoconic (KCN) and 109 eyes were nonkeratoconic (non-KCN). Twenty eyes in KCN and 79 eyes of non-KCN group had no history of contact lens use and were included for comparison with KCN and non-KCN contact lens users, respectively. Mean duration of contact lens wearing was 75.63±50.42 months. The epithelial thickness of non-KCN SCL group was thinner than that of non-KCN control subjects all over the cornea, whereas the epithelium of non-KCN HCL was thinner at central site as well as nasal and temporal paracentral and midperipheral areas. Epithelial thickness of the KCN HCL group was not different from the KCN control subjects in all sectors. The KCN SCCL group had thinner epithelium at nearly all peripheral sectors as well as inferior, inferotemporal, inferonasal, and nasal midperipheral sectors compared with KCN control subjects.

CONCLUSION

The corneal epithelium was thinner at the peripheral zones in KCN SCCL users; at both peripheral and central zones in non-KCN SCL users and in central zones in non-KCN HCL users.

Effects of long-term soft contact lens wear on corneal epithelial thickness after small incision lenticule extraction

The present study investigated changes in corneal epithelial thickness after small incision lenticule extraction (SMILE) in patients with long-term preoperative soft contact lens (SCL) wear, the impact of SCL wear on the efficacy of surgical outcomes and the effects of long-term SCL wear on postoperative corneal aberrations. Patients were assigned to three groups according to the duration of SCL wear: Group A, the non-SCL-wearing group; group B, those with SCL wear ≤1 year; and group C, those with SCL wear >1 year. Epithelial thickness was recorded in nine zones by anterior segment optical coherence tomography across a 5-mm diameter before surgery and at 1 week, and 1, 3 and 6 months post-surgery. Corneal epithelial thickness and corneal aberrations among the three groups were compared, as well as the effects of changes in corneal epithelial thickness on postoperative visual acuity and manifest refraction. No significant differences were noted with regard to age or preoperative spherical equivalent among groups A (22 eyes), B (17 eyes) and C (18 eyes). Preoperative corneal epithelial thickness in the inferonasal, inferior and inferotemporal zones was thinner in group B compared with that in group A, and corneal epithelial thickness was thinner in all nine zones in group C compared with that in group A (P<0.05). At all follow-up time points, in the central, nasal, inferonasal, inferior, inferotemporal and temporal areas, the epithelial thickness was thinner in group C compared with that in group A (P<0.05). At 3 months postoperatively, the epithelial thickness was thinner in the inferonasal and inferior sectors in group C compared with that in group B (P<0.05), and at 6 months postoperatively, the epithelial thickness in the inferior region was thinner in group C compared with that in group B (P<0.05). There were no significant differences in visual acuity or manifest refraction among the three groups at all postoperative time points. The total higher-order aberrations were greater in group C compared with those in group A for all time points (P<0.05) and were greater in group C at 1 and 3 months postoperatively compared with those in group B (P<0.05). The spherical aberrations at 3 and 6 months postoperatively were greater in group C compared with those in group A (P<0.05). The coma aberrations were greater in group C compared with those in groups A and B for all time points (P<0.05). In conclusion, long-term SCL wear will result in corneal epithelial thinning, which does not impact visual acuity or manifest refraction after SMILE.

Ocular surface microvascular response and its relation to contact lens fitting and ocular comfort: an update of recent research

This review examines vascular responses in the ocular surface to contact lens wear and its relation to lens fitting characteristics and contact lens-related discomfort. A search of PubMed was performed to find original research in English, within the past 10 years, that studied the ocular surface, including lid-wiper vascular responses to the lens. The interaction between the lens and ocular surface triggers vascular responses, impacting the lens fitting and contact lens-related discomfort. Contact lens-related discomfort is a multifactorial event, which is affected by lens characteristics. Overall, contact lenses with low modulus and a relatively tight fit produce significant ocular comfort. If an appropriate lens fit is achieved, lens fitting characteristics may not play a critical role in contact lens-related discomfort. On the other hand, the pathogenic and vascular changes of lid-wiper vascular responses appear to play an essential role in developing contact lens-related discomfort, in concert with reactions of the cornea (compression and staining) and conjunctiva (indentation and staining). Robust evaluation of lid-wiper changes at the cellular and microvascular level may hold the key to better understanding the mechanism of contact lens-related discomfort and reveal strategies for eliminating lid wiper epitheliopathy and improving ocular comfort in contact lens wearers.

CLEAR - Evidence-based contact lens practice

Evidence-based contact lens -->practice involves finding, appraising and applying research findings as the basis for patient management decisions. These decisions should be informed by the strength of the research study designs that address the question, as well as by the experience of the practitioner and the preferences and environment of the patient. This reports reviews and summarises the published research evidence that is available to inform soft and rigid contact lens history and symptoms taking, anterior eye health examination (including the optimised use of ophthalmic dyes, grading scales, imaging techniques and lid eversion), considerations for contact lens selection (including the ocular surface measurements required to select the most appropriate lens parameter, lens modality and material selection), evaluation of lens fit, prescribing (teaching self-application and removal, adaptation, care regimen and cleaning instructions, as well as -->minimising risks of lens wear through encouraging compliance) and an aftercare routine.

Tear Proteases and Protease Inhibitors: Potential Biomarkers and Disease Drivers in Ocular Surface Disease

Tears are highly concentrated in proteins relative to other biofluids, and a notable fraction of tear proteins are proteases and protease inhibitors. These components are present in a delicate equilibrium that maintains ocular surface homeostasis in response to physiological and temporal cues. Dysregulation of the activity of protease and protease inhibitors in tears occurs in ocular surface diseases including dry eye and infection, and ocular surface conditions including wound healing after refractive surgery and contact lens (CL) wear. Measurement of these changes can provide general information regarding ocular surface health and, increasingly, has the potential to give specific clues regarding disease diagnosis and guidance for treatment. Here, we review three major categories of tear proteases (matrix metalloproteinases, cathepsins, and plasminogen activators [PAs]) and their endogenous inhibitors (tissue inhibitors of metalloproteinases, cystatins, and PA inhibitors), and the changes in these factors associated with dry eye, infection and allergy, refractive surgery, and CLs. We highlight suggestions for development of these and other protease/protease inhibitor biomarkers in this promising field.

Imprinted hydrogels with LbL coating for dual drug release from soft contact lenses materials

A combined strategy to control the release of two drugs, one anti-inflammatory (diclofenac sodium, DCF) and one antibiotic (moxifloxacin hydrochloride, MXF), from a soft contact lens (SCL) material, was assessed. The material was a silicone-based hydrogel, which was modified by molecular imprinting with MXF and coated by the layer-by-layer (LbL) method using natural polyelectrolytes: alginate (ALG), poly-l-lysine (PLL) and hyaluronate (HA), crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Imprinting was used to increase the amount of MXF loaded and to sustain its release, while the LbL coating acted as a diffusion barrier for DCF and improved the surface properties. The drugs were loaded by soaking in a DCF + MXF dual solution. High hydrostatic pressure (HHP) was successfully applied in the sterilization of the drug-loaded hydrogels. The transmittance, refractive index, wettability and ionic permeability of the hydrogels remained within the required levels for SCLs application. The concentrations of the released DCF and MXF stayed above the IC₅₀ and the MIC (for S. aureus and S. epidermidis) values, for 9 and 10 days, respectively. No ocular irritancy was detected by the HET-CAM test. NIH/3T3 cell viability demonstrated that the drug-loaded hydrogels were not toxic, and cell adhesion was reduced.

Inventory of the Recommendations for Patients with Pollen Allergies and Evaluation of Their Scientific Relevance

Pollens are responsible for allergic rhinitis, conjunctivitis, and asthma. The incidence of these diseases, which have adversely impacted the social and professional lives of people who are allergic to pollen, has tripled in the past 25 years. Official institutes, health care institutions, public interest groups, and mainstream news media provide people who are allergic to pollen with advice aimed at reducing their symptoms. The aim of this work was to provide an inventory of the prevention guidelines in the world and to evaluate their scientific relevance. A PubMed search was carried out using specific keywords. The scientific relevance of the recommendations was evaluated based on the publications disproving or confirming their merit. The guidelines issued by 12 countries in Europe, North America, and Australia were inventoried. The recommendations for avoidance were most often based on scientific data regarding their impact on pollen exposures, but they have not been clinically validated. Several studies provided additional details, however, that allowed the guidelines to be further substantiated. These guidelines have been adopted in numerous industrialized countries in the world, and they generally appear to be of relevance.

Adverse events in allergy sufferers wearing contact lenses

Allergy is the fifth leading chronic condition in industrialized countries among all ages, and the third most common chronic disease among children under 18 years old. Many of allergic patients also have problems with vision and want to improve their quality of life by wearing contact lenses. They are most frequently young and active individuals, for whom contact lenses provide greater convenience and more satisfying vision correction than spectacles. However, application of high quality and immunologically neutral products do not protect from allergic side reactions. Nowadays, eye-related allergy and contact lens wear concern larger and larger populations worldwide. The purpose of this review is to summarize the studies on ocular complications associated with wearing contact lenses. The article presents indications for allergic patients especially on the care system and wear schedule.

Contact lens wearers' experiences while trekking in the Khumbu region/Nepal: a cross-sectional survey

BACKGROUND

Safe contact lens wear depends on a hygiene regime and lens-appropriate wear patterns which may be compromised during travel in remote and wilderness areas. The purpose of this study was to describe the experience of contact lens wearers while trekking at high-altitude in Nepal.

METHODS

For this descriptive study, trekkers with contact lenses were recruited in Lukla and invited to complete an online-questionnaire on trip preparation, contact lens use, care and experiences, and possible changes for future travel. Quantitative data were analysed using SurveyMonkey; content analysis applied to qualitative responses.

RESULTS

The majority of the 158 participants (124; 78.48%) reported no problems with their lenses (daily disposables, soft lenses, extended-wear lenses, hard/rigid lenses) during their stay although dry air, dust, wind, cold temperatures, and difficult hygiene maintenance were challenging. Freezing lenses and freezing solutions were additional challenges. Thirty-four (21.52%) experienced a variety of problems. Improvements were requested from manufacturers. Lodges should provide better access to clean water, mirrors and lighting. Almost 60% of participants had not sought any pre-travel health advice.

CONCLUSIONS

Remote and wilderness areas provide a challenge for appropriate contact lens wear and care. The decision between the potential risk of infection due to touching lenses (daily disposables, soft/hard lenses) and the potential risk of corneal erosion (extended-wear lenses) needs to be made in pre-travel consultations. Travel health professionals and travel agencies should remind CL-wearing trekkers to carefully assess their wear and care routine to accommodate potentially challenging conditions.

Biometric risk factors for corneal neovascularization associated with hydrogel soft contact lens wear in Korean myopic patients

PURPOSE

To investigate the biometric risk factors for corneal surface complications associated with hydrogel soft contact lens (SCL) fitting in myopic patients in Korea.

METHODS

This is a retrospective case-control study. The records of 124 subjects (124 eyes) who wore SCLs on a daily basis were reviewed. Thirty-one patients (31 eyes) who were diagnosed with corneal neovascularization (NV) while wearing SCLs were included in the complication group. Ninety-three age- and sex-matched patients (93 eyes) who wore SCLs, who did not have corneal NV and who visited our clinic for correction of refractive errors were included in the control group. The degree of spherical equivalent, astigmatism and corneal base curve radius (BCR) were compared in both groups.

RESULTS

Patients with NV exhibited poorer best corrected visual acuity and more myopia than controls (p = 0.008 and 0.006, respectively). In univariate analysis, highly myopic patients (-9 diopters [D] or higher) were more likely to experience NV (odds ratio [OR], 2.232; 95% confidence interval [CI], 1.602 to 3.105). High astigmatism (≥2 D) increased the risk of complications (OR, 2.717; 95% CI, 1.141 to 6.451). Steep cornea, in which BCR was <7.5 mm, also raised the risk of complications (OR, 4.000; 95% CI, 1.661 to 9.804). Flat cornea was not a risk factor for the development of NV.

CONCLUSIONS

High myopia, high astigmatism, and steep cornea seemed to be risk factors in the development of corneal NV in SCL wearers.

The effect of tinted soft contact lens wear on functional visual acuity and higher-order aberrations

PURPOSE

To investigate the differences of functional visual acuity (FVA) and high order aberrations (HOAs) in relation to tinted and clear hydrogel soft contact lens (SCL) wear.

METHODS

A prospective comparative study was performed in 16 eyes of 16 healthy volunteers. Dynamic visual acuity (using a FVA measurement system) and higher-order aberrations (using a wavefront sensor) were compared in subjects wearing two types of soft contact lenses: 1-day Acuvue(®) (Vistakon, Jacksonville, FL) clear and the 1-day Acuvue(®) Define(TM) (Vistakon, Jacksonville, FL) tinted lens. The blink rates were recorded during FVA testing. The correlation between the difference of HOAs and differences in FVA values was analyzed.

RESULTS

The mean LogMAR FVA scores with clear and tinted SCLs were 0.07 ± 0.13 and 0.14 ± 0.17 (P<0.05). The mean blink frequencies with clear and tinted SCL wear were 18.4 ± 8.3 and 25.3 ± 4.7 blinks/min (P<0.05). Both 3rd-order aberrations and total HOAs showed statistically significant differences between the two types of soft contact lenses for 6mm pupil measurements (P<0.05). A significant positive linear correlation was observed between ΔHOAs and ΔLogMAR FVA for 6mm pupil measurements (R=0.53, P=0.04).

CONCLUSIONS

Tinted contact lens wear appears to induce a reduction in optical quality. Functional visual acuity measurement is a useful procedure to study the changes of visual performance and quality in tinted contact lens wear.

TREM-2 promotes host resistance against Pseudomonas aeruginosa infection by suppressing corneal inflammation via a PI3K/Akt signaling pathway

PURPOSE

To explore the role of triggering receptor expressed on myeloid cells 2 (TREM-2) in Pseudomonas aeruginosa (PA) keratitis.

METHODS

BALB/c mice were routinely infected with PA and evaluated at various postinfection time points for corneal expression of TREM-2, by real-time PCR, Western blot, and flow cytometry. Next, BALB/c and C57BL/6 mice were respectively treated with TREM-2 siRNA or agonistic anti-TREM-2 antibody, to determine the role of TREM-2 in PA keratitis. Bacterial load and neutrophil infiltration were tested by plate count and myeloperoxidase assay, respectively. Th1-/Th2-type and proinflammatory cytokine expression were tested by real-time PCR and ELISA after in vivo and in vitro silencing of TREM-2. Moreover, phosphorylated Akt levels were tested by Western blot in murine macrophages after treatment with agonistic anti-TREM-2 antibody. mRNA levels of proinflammatory cytokines were examined in murine macrophages after TREM-2 activation and lipopolysaccharide stimulation, following pretreatment with inhibitors for PI3K or Akt, to determine whether PI3K/Akt is required in TREM-2-mediated immune modulation. In addition, BALB/c mice were treated with wortmannin and analyzed for bacterial load and proinflammatory cytokine expression.

RESULTS

TREM-2 expression was elevated in the infected BALB/c corneas at 3 or 5 days postinfection. Silencing of TREM-2 accelerated disease progression by enhancing bacterial load and corneal inflammation, whereas activation of TREM-2 promoted host resistance to PA keratitis. PI3K/Akt signaling is required in the TREM-2-mediated immune modulation, and inhibition of PI3K resulted in worsened disease after PA corneal infection.

CONCLUSIONS

TREM-2 promoted host resistance to PA infection by suppressing corneal inflammation via activation of the PI3K/Akt pathway.

Three-year follow-up of secondary anterior iris fixation of an aphakic intraocular lens to correct aphakia

PURPOSE

To evaluate the efficacy, predictability, stability, safety, and complications of secondary anterior iris fixation of the Artisan iris-fixated intraocular lens (IOL) to correct aphakia in eyes without sufficient capsule support.

SETTING

Department of Ophthalmology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.

DESIGN

Cohort study.

METHODS

Eyes having implantation of aphakic iris-fixated IOLs for aphakia correction were followed for 3 years.

RESULTS

The study evaluated 72 eyes (72 patients). After 3 years, the uncorrected distance visual acuity improved in all eyes (P<.05); 53 eyes (73.6%) reached 20/40 or better. Two eyes had a postoperative corrected distance visual acuity (CDVA) worse than the preoperative CDVA due to postoperative ischemic optic neuropathy and retinal detachment, respectively. The mean spherical equivalent (SE) decreased from 11.65 diopters (D) ± 1.21 (SD) to -0.58 ± 0.56 D (P<.05); the SE at the last follow-up was within ±1.00 D of the target refraction in 63 eyes (87.5%). The mean endothelial cell loss 3 years postoperatively was 9.78%. There was no significant postoperative intraocular pressure increase throughout the follow-up. Twelve patients (16.7%) reported glare and halos during night driving. Iris pigment precipitates on the IOLs occurred in 4 eyes (5.6%) 3 years postoperatively. No other serious complications occurred.

CONCLUSIONS

Three-year results indicate that secondary implantation of aphakic IOLs is effective, predictable, and safe for the correction of aphakia in eyes without capsule support. However, longer follow-up with a larger cohort is necessary to confirm these conclusions.