Central corneal thickness in new cases of dry eyes: A case-control study.

SIGNIFICANCE: Loss of homeostasis and chronic inflammation result in ocular surface damage in dry eyes, which is also associated with corneal thinning in established cases. Yet, the correlation between corneal thickness and new cases of dry eyes remains inadequately supported by evidence. PURPOSE: This study aimed to compare the central corneal thickness of new cases of dry eyes to that of age- and gender-matched controls. METHODS: A total of 45 dry eye patients were compared with 61 age- and gender-matched non-dry eye individuals. The Ocular Surface Disease Index (OSDI) questionnaire was used to evaluate symptoms, and the central corneal thickness was measured with a Nidek CEM-530 specular microscope. Patients were grouped based on disease severity (OSDI scores), and the clinical findings were compared between groups for slit-lamp examinations, Schirmer's I test, and tear film breakup time. RESULTS: The median age of patients was 25.0 (interquartile range [IQR], 20.0 to 32.0) and 27.0 (IQR, 20.0 to 32.0) years in the control and dry eye groups, respectively (p=0.63). The median (IQR) values of the OSDI scores, tear film breakup time scores, and Schirmer's test measurements in the control groups were 10.4 (8.3 to 10.4), 12.0 (11.0 to 14.0) seconds, and 16.0 (13.5 to 19.5) mm, respectively, which differed from the dry eye groups (p<0.0001). These values in the dry eye group were 29.1 (25.0 to 39.5), 4.0 (3.0 to 8.0) seconds, and 8.0 (3.5 to 11.0) mm, respectively. Patients with dry eyes had lower central corneal thickness than controls (p<0.01). The mean ± standard deviation central corneal thicknesses in patients with dry eyes and the control group were 520.3 ± 26.8 and 545.3 ± 18.8 µm, respectively. CONCLUSIONS: The central corneal thickness in dry eyes was significantly reduced compared with the control group. These findings may be useful in monitoring and managing dry eyes and should be considered in intraocular pressure measurements and refractive surgical procedures.

Mean Amplitude of Diurnal Variation of Sub-Foveal Choroidal Thickness among Adults with Healthy Eyes Visiting Outpatient Department of a Tertiary Eye Care Centre.

Introduction: The choroid, particularly the choroidal vasculature, plays an important role in the pathophysiology of various ocular diseases. Diurnal variation in the thickness of the choroid has been reported in previous studies. This study aimed to find the mean amplitude of diurnal variation of sub-foveal choroidal thickness among adults with healthy eyes visiting the outpatient Department of a tertiary eye care centre. Methods: A descriptive cross-sectional study was conducted among adults with healthy eyes presenting to the outpatient Department of a tertiary eye care centre from 1 February 2023 to 3 June 2023 after obtaining ethical approval from the Institutional Review Committee. After a comprehensive medical eye examination, sub-foveal choroidal thickness measurement was performed using enhanced depth imaging optical coherence tomography at the baseline and subsequent interval afterwards. A convenience sampling method was used. The point estimate was calculated at a 95% Confidence Interval. Results: Among 60 eyes, the mean amplitude of the diurnal variation of subfoveal choroidal thickness was 35.16±14.08 microns (31.59-38.72, 95% Confidence Interval). The mean amplitude for the right eye was 36.30±14.08 microns, and for the left eye, it was 34.23±14.08 microns. Conclusions: The amplitude of diurnal variation of subfoveal choroidal thickness from this study was found to be similar to other studies done in international settings. Keywords: choroid; circadian rhythm; cross-sectional study; Ophthalmology.

Positive Microbiological Culture among Patients with Infective Keratitis Visiting the Cornea Unit of a Tertiary Care Centre.

Introduction: Keratitis is the infection and inflammation of the cornea. Microbial keratitis is a potentially sight-threatening corneal condition. The aim of this study was to find out the prevalence of positive microbiological culture among patients with infective keratitis visiting the Cornea Unit of a tertiary care centre. Methods: A descriptive cross-sectional study was conducted among patients with a clinical diagnosis of infective keratitis presenting to the Cornea Unit of a tertiary eye care centre from 16 October 2020 to 16 March 2021 after obtaining ethical approval from the Ethical Review Board. After slit-lamp examination, corneal scrapings were performed under aseptic conditions which were subjected to Gram stain, potassium hydroxide preparation and culture for bacterial and fungal pathogens. A convenience sampling method was used. The point estimate was calculated at a 95% Confidence Interval. Results: Among 428 patients, 337 (78.73%) (73.24-84.33, 95% Confidence Interval) had a positive microbiological culture. A total of 213 (49.76%) of enrolled samples had a prior history of ocular trauma. Aspergillus species 68 (20.17%) and Streptococcus species 33 (9.79%) were the most common organisms isolated from fungal and bacterial corneal ulcers respectively. Conclusions: The prevalence of positive microbiological culture among patients with infective keratitis from this study is similar to the pattern reported from similar settings. Keywords: corneal ulcer; keratitis; prevalence.

Normative Vascular Features on OCT Angiography in Healthy Nepalese Eyes.

Purpose: To establish normative data on morphological characteristics and quantitative parameters of Foveal Avascular Zone (FAZ) as well as their systemic and ocular associations using OCT angiography (OCT-A) in healthy Nepalese subjects. Patients and Methods: A prospective, cross-sectional, population-based study recruiting 210 healthy samples (420 eyes) aged 10 to 70 years was conducted. All the samples underwent detailed comprehensive eye examination followed by Optical Coherence Tomography Angiography (OCTA) and Enhanced Depth Imaging performed in each eye using Spectral Domain Optical Coherence Tomography. Foveal avascular zone area and vessel density in superficial and deep retinal plexus and Sub foveal Choroidal Thickness (SFCT) were evaluated. Ocular and systemic associations of these parameters were also studied in a multivariate analysis utilizing linear regression. Results: The mean superficial and deep FAZ area was 459.96 ± 124.75 µm (95% confidence interval [CI], 443.08-476.83) and 589.0 ± 141.39 µm (95% CL, 570.77-609.02), respectively. The vessel density in superficial capillary plexus was 54.03 ± 9.34% (95% CL, 53.98-54.11) while the vessel density in deep capillary plexus was 25.91 ± 38% (95% CL, 25.85-25.96). The mean SFCT in this study was 308.89 ± 68.87µm (95% CL, 299.64-318.14 µm). There was no statistically significant inter-eye difference in the FAZ parameters. Myopic eyes had smaller FAZ, lesser vessel density and thinner SFCT. Association was observed between superficial FAZ area and systolic blood pressure, and deep FAZ area and diastolic blood pressure. Conclusion: This study reports the normative data on FAZ parameters in healthy Nepalese subjects which can serve as references for interpreting these parameters in different retinal-choroidal diseases.

A Combined Intervention of Single Vision Plus Lens and Tropicamide in the Treatment of Pseudomyopia: A Perspective Case Report from Nepal.

This study highlights the role of cycloplegic refraction in the detection of accommodative spasm and the use of tropicamide 1% as cycloplegic and single vision plus lens for its management. This was a case study carried at tertiary eye hospital in Kathmandu, Nepal. In this study, 2 subjects presenting with complain of sudden onset of diminution of vision for near and distance along with asthenopic symptoms having history of prolonged near work were recruited. Pre-cycloplegic refraction showed fluctuating myopic refractive error which after cycloplegia showed a significant hyperopic shift. Single vision plus lens (base on post-mydriatic treatment) giving optimal vision for near and distance along with tropicamide 1% twice a day basis and abstinence of triggering factor was started as initial treatment modality. Subjects were kept under close surveillance and followed up fortnightly over 2 months. During this period, the dosages of tropicamide were gradually tapered based on symptomatic relief of patient and no recurrence of the condition was observed in both subjects for next 2 month.

Blindness among Patients with Type II Diabetes Mellitus Presenting to the Outpatient Department of Ophthalmology of a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Introduction: Diabetic retinopathy is a major microvascular complication of diabetes, and may progress to sight-threatening stages causing blindness with a consequent decrease in their quality of life. This study aimed to find out the prevalence of blindness among patients with type II diabetes mellitus attending the Outpatient Department of Ophthalmology of a tertiary care hospital. Methods: A descriptive cross-sectional study was conducted among patients with type II diabetes mellitus presenting to the Outpatient Department of Ophthalmology of a tertiary care centre from 2 August 2021 to 30 June 2022 after receiving ethical approval from the Institutional Review Committee (Reference number: 74/2021). Diabetic patients underwent detailed eye examination including vision, slit lamp biomicroscopy examination, and fundus evaluation with full pupil dilation. Convenience sampling method was used. Point estimate and 95% Confidence Interval were calculated. Results: Among 449 type II diabetic patients, blindness was seen in 17 (3.79%) (2.02-5.56, 95% Confidence Interval) patients. Among them, 1 (5.88%) had severe non-proliferative diabetic retinopathy, 3 (17.65%) had proliferative diabetic retinopathy and 8 (47.06%) had severe diabetic macular oedema. Conclusions:  The prevalence of blindness among patients with type II diabetes mellitus was less than in other studies conducted in similar settings. Screening and timely management of diabetic retinopathy could reduce the prevalence of blindness due to diabetic retinopathy. Keywords: blindness; diabetic retinopathy; prevalence.

Non-strabismic Binocular Vision Dysfunction among the Medical Students of a Teaching Hospital: A Descriptive Cross-sectional Study.

Introduction: Non-strabismic binocular vision dysfunctions are visual disorders that affect the person's binocular vision and visual outcome while performing near tasks and are very common among medical students. This study aimed to find out the prevalence of non-strabismic binocular vision dysfunction among the medical students of a teaching hospital. Methods: A descriptive cross-sectional study was conducted among medical students of a teaching hospital from 25 April 2022 to 25 May 2022. Ethical approval was obtained from the Institutional Review Committee of the same institute (Reference number: 139/17). A detailed ocular evaluation including history, visual acuity, refraction, and detailed orthoptic evaluation was done. Convenience sampling was done. Point estimate and 95% Confidence Interval were calculated. Results: Out of 284 students, 79 (27.81%) (22.60-33.02, 95% Confidence Interval) had non-strabismic binocular vision dysfunctions. Convergence insufficiency was the commonest one seen in 38 (48.10%), followed by divergence excess seen in 8 (10.12%) and convergence excess seen in 8 (10.12%) students. Conclusions: The prevalence of non-strabismic binocular vision dysfunction among medical students was lower than in other studies conducted in similar settings. Keywords: binocular vision; convergence excess; convergence insufficiency; prevalence.

Computational study for temperature distribution in ArF excimer laser corneal refractive surgeries using different beam delivery techniques.

Refractive errors are the most common causes of vision impairment worldwide and laser refractive surgery is one of the most frequently performed ocular surgeries. Clinical studies have reported that approximately 10.5% of patients need an additional procedure after the surgery. The major complications of laser surgery are over/under correction and dry eye. An increase in temperature may be a cause for these complications. The purpose of this study was to estimate the increase in temperature during laser refractive surgery and its relationship with the complications observed for different surgical techniques. In this paper, a finite element model was applied to investigate the temperature distribution of the cornea when subjected to ArF excimer laser at a single spot using various beam delivery systems (broad beam, scanning slit, and flying spot). The Pennes bio-heat equation was used to predict the temperature values at different laser pulse energies and frequencies. The maximum temperature increase by ArF laser ([Formula: see text] frequency and [Formula: see text] pulse energy) at a single spot was [Formula: see text] for [Formula: see text] diopter correction ([Formula: see text] of ablation of corneal stroma) using broad beam, scanning slit, and flying spot beam delivery approaches respectively. The peak temperature due to a single pulse was estimated to be [Formula: see text]. Although the peak temperature (sufficient energy to break intermolecular bonds) exists for a very short time ([Formula: see text]) compared to the thermal relaxation time ([Formula: see text]), there is some thermal energy exchange between corneal tissues during a laser refractive surgery. Heating may cause collagen denaturation, collagen shrinkage, and more evaporation and hence proposed to be a risk factor for over/under correction and dry eye.

Review on current concepts of myopia and its control strategies.

Myopia poses a significant burden on the healthcare system, economy and quality of life. It is an emerging global public health challenge and requires interventions to delay or stop onset and progression. With changing times and evidence, the concepts of myopia are changing along with the treatment and control strategies. Behavioural modifications including increased outdoors time and reduced near work, optical and pharmaceutical management options are reviewed. This paper presents a current overview on the concepts of myopia, and is expected to summarize updates on myopia control methods.

Mobile health intervention for promotion of eye health literacy.

PURPOSE: Improving eye health awareness in the underserved population is a universal eye health priority. The ubiquity of cell phones and internet usage provides new and innovative opportunities for health promotion. This study evaluated the effect of mobile health intervention (text message link) to promote eye health literacy (EHL) of priority ocular morbidities. METHODS: This study was an intervention evaluation and employed a two-armed pre-test post-test approach. Baseline assessment on EHL was performed on 424 university students. Participants were categorised into intervention and control groups, using the 1:1 allocation ratio. The intervention and control group received a text message alone and text message with a link, respectively. EHL was assessed via a self-administered questionnaire. The primary outcome measures were changes in EHL scores between baseline and one month post-intervention. Descriptive analysis was performed to assess the cost-effectiveness of the intervention. RESULTS: With low attrition and a response rate of 95.6%, 409 responses were eligible for analysis. The mean age of the participants (49.4% males and 50.6% of females) was 19.9±1.68 years. Baseline EHL scores were low, and there was no correlation with a demographic profile (all p<0.05, CI 95%). The demographic characteristics were similar between the two groups (for all, P <0.05, CI 95%) at baseline. The EHL scores improved in both groups between the pre-and post-test assessment; however, improvements were statistically significant only in the control group. The one-month post-intervention EHL scores were also higher in the intervention group compared to the control (p≤0.001, CI 95% for all). The total cost incurred for the intervention used was 11.5 USD. CONCLUSION: Text message link demonstrated effectiveness for improving the EHL scores; the low baseline EHL scores substantially improved with intervention. The text message link intervention is a cost-effective method and could be considered in advocating for eye health in developing countries, particularly during global emergencies.

Constructing Item Banks for Measuring Quality of Life in Refractive Error.

SIGNIFICANCE: Existing patient-reported outcome instruments in refractive error are paper-based questionnaires. They are not comprehensive and psychometrically robust. This study has identified the content of the refractive error-specific item banks that aim to provide comprehensive and scientific measurement of refractive error-specific quality of life. PURPOSE: The purpose of this study was to identify minimally representative, optimally informative, and efficient sets of items for measuring quality of life in people with refractive error. METHODS: First, items were identified from existing patient-reported outcome instruments. Second, items were developed from qualitative studies with people with refractive error (48 and 101 in-depth interviews in Australia and Nepal, respectively). Third, classification and selection of items were done based on a set of systematic criteria using an iterative process of binning and winnowing. The resulting items underwent cognitive testing with people with refractive error in Australia and in Nepal. Each step was guided by an expert panel consensus. RESULTS: We retrieved 792 items from the existing patient-reported outcome instruments. From the interviews conducted in Australia, a total of 2367 comments were coded into 807 initial items. Similarly, from the interviews conducted in Nepal, 3477 comments were coded into 914 initial items. After binning and winnowing, followed by cognitive testing, a final set of items comprising 337 items for the Item-pool (Australia) and 308 items for the Item-pool (Nepal), both spanning 12 domains, was obtained. Forty-seven percent of items were common across the two item pools. In the Item-pool (Nepal), 65% items were common for corrected and uncorrected refractive error. CONCLUSIONS: We identified the content of two different sets of item banks to comprehensively measure the impact of refractive error on quality of life for people in Australia and Nepal, which may be applicable to high-income country settings and low- and middle-income country settings, respectively. Future work aims to develop computer-adaptive testing system to administer the item banks, resulting in useful measurement tools for researchers, clinicians, and policy planners.

Prevalence of myopia and binocular vision dysfunctions in microscopists / 国际眼科杂志(Guoji Yanke Zazhi)

·AIM: To determine the refractive and binocular vision status in clinical microscopists. ·METHODS: It was an observational and cross sectional hospital based study. One hundred and three microscopists working at Tribhuvan University Teaching Hospital were recruited in the study. All subjects had a comprehensive eye examination including static retinoscopy, dynamic retinoscopy and orthoptic evaluation. Information about their visual symptoms associated with microscopy was also collected. ·RESULTS: The prevalence of refractive error in this group of microscopists was 69. 90% . Majority of the subjects were myopic (68. 93% of total subjects) with the mean myopic error of - 1. 58 ± 1. 89 D. Convergence insufficiency was found in 61. 20% of the study population. Prevalence of accommodative insufficiency and infacility were 41. 30% and 40. 06% respectively. Fusional vergence was also reduced in this study population. The outcomes of this study were expected to increase the awareness about the refractive and binocular vision anomalies among this population. · CONCLUSION: There was found to be increased prevalence of refractive error in clinical microscopists, especially myopia. Majority of them had vergence and accommodative anomalies. Most of the subjects reported asthenopic symptoms associated with their microscopy work, which may affect their work efficiency.

Contact lenses for visual rehabilitation in Bilateral Nanophthalmos with Retinal Dystrophy- A case report.

BACKGROUND: Nanophthalmos is an uncommon developmental ocular disorder characterized by a small eye with short axial length, high hyperopia and high lens to eye volume ratio due to arrested development of the globe in all directions. Different types of fundus changes can rarely occur with nanophthalmos. OBSERVATIONS: This is a case report of a 17 years old female who presented with bilateral gradual progressive visual loss and photophobia at Tilganga Institute of Ophthalmology on 3rd July 2015. Her best corrected visual acuity was 20/300 with +12.00Ds/-1.00Dcyl@180 in the right eye and 20/200 with +12.00Ds/-1.50Dcyl@180 in the left eye. Axial lengths of two eyes were markedly shortened with pigmentary changes at the macula and dull foveal reflex along with retinal flecks in the mid-periphery. Full field ERG showed diminished rod and cone waves suggestive of rod and cone dysfunction. With the use of Rigid Gas Permeable (RGP) contact lenses, the acuity improved to 20/200 and 20/125 in the right and left eye respectively. CONCLUSION: This study proposes the use of contact lenses and light absorptive filters for better visual rehabilitation.

Visual functions and disability in diabetic retinopathy patients.

PURPOSE: This study was undertaken to find correlations between visual functions and visual disabilities in patients with diabetic retinopathy. METHOD: A cross-sectional study was carried out among 38 visually impaired diabetic retinopathy subjects at the Low Vision Clinic of B.P. Koirala Lions Centre for Ophthalmic Studies, Kathmandu. The subjects underwent assessment of distance and near visual acuity, objective and subjective refraction, contrast sensitivity, color vision, and central and peripheral visual fields. The visual disabilities of each subject in their daily lives were evaluated using a standard questionnaire. Multiple regression analysis between visual functions and visual disabilities index was assessed. RESULT: The majority of subjects (42.1%) were of the age group 60-70 years. Best corrected visual acuity was found to be 0.73±0.2 in the better eye and 0.93±0.27 in the worse eye, which was significantly different at p=0.002. Visual disability scores were significantly higher for legibility of letters (1.2±0.3) and sentences (1.4±0.4), and least for clothing (0.7±0.3). Visual disability index for legibility of letters and sentences was significantly correlated with near visual acuity and peripheral visual field. Contrast sensitivity was also significantly correlated with the visual disability index, and total scores. CONCLUSION: Impairment of near visual acuity, contrast sensitivity, and peripheral visual field correlated significantly with different types of visual disability. Hence, these clinical tests should be an integral part of the visual assessment of diabetic eyes.