Mechanism and clinical significance of superficial micropunctate fluorescein staining of the cornea

It is for well over a century that fluorescein has been used as a preferred dye for identifying and enhancing corneal surface change. Superficial micropunctate staining of the corneal epithelium is the most commonly encountered clinical manifestation of fluorescein staining. Despite its well accepted use, neither the cellular basis nor the clinical significance of this regularly seen phenomenon are yet clear. Despite this uncertainty, the presence of corneal staining has traditionally been used as a clinical tool to identify corneal surface changes. Recent literature reports have argued for more thorough scientific evidence to be produced attesting to the exact status of the corneal epithelium when it appears to have stained with fluorescein.In this thesis we systematically evaluated the mechanism and clinical significance of superficial micropunctate fluorescein staining of the cornea. A series of experiments were designed to determine the cellular basis of corneal staining. Six mechanisms were identified from literature reports, these were pooling of fluorescein in voids on the ocular surface, accumulation of dye solution in intercellular spaces, staining of live, damaged or dead cells, a response to exposed cells un-protected by the mucin layer and the possibility that the staining appearance is an artefact. Evaluations were aimed to determine which of these mechanisms dominates in the process.A staining model was developed to facilitate evaluation in human subjects and when this could not be used due to safety or ethical considerations, in vitro cell culture and ex vivo organ culture models were utilized. Observations were performed at high magnification and were aided by simultaneous staining with metabolic dyes to identify live, apoptotic and dead cells. The results of these studies suggest that healthy corneal epithelial cells take up fluorescein to a moderate level and dead cells stain minimally. Fluorescent intensities associated with both these situations are not typically observed with clinical slit-lamp bio-microscopy. Irrespective of the cause of insult, apoptotic cells were associated with bright florescence, i.e. hyper-fluorescence relative to the background of normal cells. We conclude that the bright fluorescence perceived as micropunctate dots on ocular surface when observed with slit-lamp bio-microscope indicates apoptotic, but not dead, cells. Such staining was also associated with an increase in the level of some, but not all inflammatory mediators in the tear film

The impact of COVID-19 on compliance to amblyopia treatment in a tertiary eye care center

Purpose: To investigate the impact of the coronavirus disease 2019 (COVID-19) outbreak on compliance to amblyopia therapy from the perspective of parents of amblyopic children. Methods: The participants for the qualitative study were enrolled from the medical records of a tertiary eye care center during the COVID-19 pandemic. The trained researcher conducted telephonic interviews consisting of validated 15 open-ended questions for 15 min. The questions were related to patients' compliance toward amblyopia treatment and the date of follow-up with their practitioners. The data collected were entered on Excel sheets in the participant's own words and later converted to a transcript for analysis. Results: A total of 217 parents of children with amblyopia who were due for follow-up were contacted through telephone. The response rate for willingness to participate was only 36% (n = 78). Of these, 76% (n = 59) of parents reported that their child was compliant toward the treatment during the therapy period and 69% reported that their child was currently not on treatment for amblyopia. Conclusion: In the current study, we have observed that although reported compliance by parents during the therapy period was good, around 69% of patients had discontinued amblyopia therapy. The main reason for the discontinuation of therapy was the failure to visit the hospital during the scheduled follow-up with the eye care practitioner

Prevalence of refractive errors in urban school children in India: The Hyderabad Eye Study

Purpose: To determine the prevalence of refractive errors in urban schoolchildren from Hyderabad, India.Methods: Prospective, cross-sectional evaluation of the ocular health of a sample of urban school children from Hyderabad,India. Five schools from various zones of Hyderabad were randomly selected and all children aged 6 to 15 yrs(n=2347) were considered. Informed consent was obtained from all children. Following unaided, aided visual acuity and slit lamp biomicroscopy, eyes were cyclopleged with 1% tropicamide. Following cycloplegia, autorefraction,subjective refraction and posterior segment evaluation with direct ophthalmoscopy was conducted. Using data from worst eye, myopia was defined as cycloplegic spherical equivalent ≤-0.50D, emmetropia as >-0.50D to +0.50D and hyperopia of ≥ +0.50D. Astigmatism was a cylindrical refractive error of ≥1.0D. Prevalence and 95% confidence intervals (CI) are presented. Influence of gender, age and school on myopia was assessed using logistic regression.Results: Of the 2347 participants, data for 2259 eligible children (11.3 ± 2.3 yrs) was considered. Prevalence of myopia, hyperopia, astigmatism and emmetropia with cycloplegic autorefraction was 35.5%(CI:33.5-37.4),14.6%(CI:13.1-16.0), 3.6%(CI:2.9-4.4) and 46.3%(CI:44.3-48.4) respectively and with subjective refraction was 21.3%(CI:19.6-23.0), 4.5%(CI:3.6-5.3), 3.5%(CI:2.8-4.3) and 70.7%(CI:68.8-72.5) respectively. Difference in the prevalence of refractive error between cycloplegic autorefraction and subjective refraction was due to children preferring no correction over low levels of myopic,astigmatic as well as hyperopic prescriptions. Myopia was associated with age (p<0.001) and school (p=0.032) but not gender. Myopia increased with age with a prevalence of 17.4%, 34.4%, 46.6% and 39.4% for ages 6,10,12 and 14 respectively. For the 5 schools, myopia prevalence ranged between 26% to 47.4%. The school with the highest prevalence had children with parents from a middle to low socioeconomic status. Prevalence of high myopia (≤-6.00D) was 0.8%(CI:0.4-1.2).Conclusions: Compared to previous studies, a greater prevalence of myopia was found in urban school children in Hyderabad. This shift reflects the global trend towards increasing myopia prevalence and indicates a need for public health policies and strategies around eye health to avoid uncorrected refractive error and to reduce the prevalence and progression of myopia

Prevalence and Patterns of Refractive Errors in Children and Young Adults in an Urban Region in South India:the Hyderabad Eye Study

Purpose: To determine the prevalence of refractive error (RE) and associated risk factors for myopic refractive errors in children and young adults from the urban region of Hyderabad, South India. Methods: Four thousand sixty-five (4,065) participants aged 6–22 years were enrolled and examined in this cross-sectional study conducted from October 2013 to January 2015. Participants were enrolled from a random sample of schools and universities in regions representative of urban Hyderabad. RE was determined using cycloplegic autorefraction. The association of demographic factors such as age, gender, and socio-economic category (SEC) (low/mid/high) with myopia was explored with logistic regression with robust standard error. Results: Of the total participants, 2,259 were children aged 6–15 years and 1,806 were adolescents and young adults aged 16–22 years. Overall prevalence of myopia, high myopia (≤ −5.00D and ≤ −6.00 D), hyperopia, emmetropia, and astigmatism was 29.8% (95% CI: 26.0% to 33.6%, n = 1,216), 2.9% (95% CI: 1.9% to 3.9%, n = 120), 1.1% (95%CI: 0.7% to 1.5%, n = 46), 14.7% (95% CI: 12.4% to 17.0%, n = 599), 46.9% (95% CI: 43.7% to 50.1%, n = 1913) and 8.6% (95% CI: 7.4% to 9.9%, n = 352) respectively. A strong correlation existed between age and prevalence of myopia (R2 = 0.88, p &lt; .001) and high myopia (R2 = 0.71, p &lt; .001). Children from schools of low SEC (34.7%) had higher prevalence of myopia compared to the mid SEC (16.8%) (p = .043). Conclusion: Myopia was the most prevalent refractive error and increased with age in this urban population. More myopia was observed in schools of low SEC.</p

TFOS lifestyle: Impact of contact lenses on the ocular surface

Several lifestyle choices made by contact lens wearers can have adverse consequences on ocular health. These include being non-adherent to contact lens care, sleeping in lenses, ill-advised purchasing options, not seeing an eyecare professional for regular aftercare visits, wearing lenses when feeling unwell, wearing lenses too soon after various forms of ophthalmic surgery, and wearing lenses when engaged in risky behaviours (e.g., using tobacco, alcohol or recreational drugs). Those with a pre-existing compromised ocular surface may find that contact lens wear exacerbates ocular disease morbidity. Conversely, contact lenses may have various therapeutic benefits. The coronavirus disease-2019 (COVID-19) pandemic has impinged upon the lifestyle of contact lens wearers, introducing challenges such as mask-associated dry eye, contact lens discomfort with increased use of digital devices, inadvertent exposure to hand sanitizers, and reduced use of lenses. Wearing contact lenses in challenging environments, such as in the presence of dust and noxious chemicals, or where there is the possibility of ocular trauma (e.g., sport or working with tools) can be problematic, although in some instances lenses can be protective. Contact lenses can be worn for sport, theatre, at high altitude, driving at night, in the military and in space, and special considerations are required when prescribing in such situations to ensure successful outcomes. A systematic review and meta-analysis, incorporated within the review, identified that the influence of lifestyle factors on soft contact lens dropout remains poorly understood, and is an area in need of further research. Overall, this report investigated lifestyle-related choices made by clinicians and contact lens wearers and discovered that when appropriate lifestyle choices are made, contact lens wear can enhance the quality of life of wearers