The role of naturally acquired intracellular Pseudomonas aeruginosa in the development of Acanthamoeba keratitis in an animal model.

BACKGROUND: Acanthamoeba is an environmental host for various microorganisms. Acanthamoeba is also becoming an increasingly important pathogen as a cause of keratitis. In Acanthamoeba keratitis (AK), coinfections involving pathogenic bacteria have been reported, potentially attributed to the carriage of microbes by Acanthamoeba. This study assessed the presence of intracellular bacteria in Acanthamoeba species recovered from domestic tap water and corneas of two different AK patients and examined the impact of naturally occurring intracellular bacteria within Acanthamoeba on the severity of corneal infections in rats. METHODOLOGY/PRINCIPAL FINDINGS: Household water and corneal swabs were collected from AK patients. Acanthamoeba strains and genotypes were confirmed by sequencing. Acanthamoeba isolates were assessed for the presence of intracellular bacteria using sequencing, fluorescence in situ hybridization (FISH), and electron microscopy. The viability of the bacteria in Acanthamoeba was assessed by labelling with alkyne-functionalized D-alanine (alkDala). Primary human macrophages were used to compare the intracellular survival and replication of the endosymbiotic Pseudomonas aeruginosa and a wild type strain. Eyes of rats were challenged intrastromally with Acanthamoeba containing or devoid of P. aeruginosa and evaluated for the clinical response. Domestic water and corneal swabs were positive for Acanthamoeba. Both strains belonged to genotype T4F. One of the Acanthamoeba isolates harboured P. aeruginosa which was seen throughout the Acanthamoeba's cytoplasm. It was metabolically active and could be seen undergoing binary fission. This motile strain was able to replicate in macrophage to a greater degree than strain PAO1 (p<0.05). Inoculation of Acanthamoeba containing the intracellular P. aeruginosa in rats eyes resulted in a severe keratitis with increased neutrophil response. Acanthamoeba alone induced milder keratitis. CONCLUSIONS/SIGNIFICANCE: Our findings indicate the presence of live intracellular bacteria in Acanthamoeba can increase the severity of acute keratitis in vivo. As P. aeruginosa is a common cause of keratitis, this may indicate the potential for these intracellular bacteria in Acanthamoeba to lead to severe polymicrobial keratitis.

Kaleidos-based binocular vision analyzer for the estimation of refractive errors and horizontal ocular deviation in children.

CLINICAL RELEVANCE: Knowing the agreement and interobserver variability of the 2WIN-S photorefractometer with cycloplegic retinoscopy and prism cover test is important for judging the clinical usefulness of the device. BACKGROUND: This study aims to determine an agreement and interobserver reliability between 2WIN-S photorefractometer and cycloplegic retinoscopy for estimating refractive errors and between 2WIN-S and prism cover test for measuring horizontal ocular deviation in children. METHODS: Two groups of 129 and 64 participants (range, 5 to 16 years) were recruited for the agreement and interobserver reliability studies, respectively. Non-cycloplegic 2WIN-S refraction was compared with cycloplegic retinoscopy for low and moderate myopia and hyperopia. Similarly, corneal reflex-function (CR-function) of 2WIN-S was compared with prism cover test for horizontal ocular deviation. Bland-Altman plots were used to depict agreement, and the intraclass correlation coefficient (ICC) was used for determining interobserver reliability of repeated measures. RESULTS: The mean differences in spherical equivalent, J0 (Cartesian astigmatism) and J45 (oblique Jackson cross-cylinder) between cycloplegic retinoscopy and 2WIN-S were 1.10 (95% CI = 0.97 to 1.21, p < 0.001), -0.06 (95% CI = -0.09 to -0.03, p < 0.001) and 0.009 (95% CI = -0.01 to 0.03, p = 0.35), respectively. The overall median difference in the horizontal ocular deviation between prism cover test and 2WIN-S was -4.5 (Interquartile range = -12.0 to 4.0). For constant strabismus, this difference was insignificant (median= -2.0, interquartile range = -11.0 to 6.7, p = 0.19) between prism cover test and 2WIN-S. The ICC was high for the spherical equivalent (0.997; p < 0.001), J0 (0.932; p < 0.001) and J45 (0.901; p < 0.001), whereas it was low-to-moderate for horizontal ocular deviation (0.50; p < 0.001). CONCLUSION: 2WIN-S refraction was in agreement with cycloplegic retinoscopy for low and moderate myopia and hyperopia, and requires an adjustment for the consistent differences between cycloplegic retinoscopy and 2WIN-S refraction. The measurement of constant strabismus with 2WIN-S is comparable to that of prism cover test.

Human tear metabolites associated with nucleoside-signalling pathways in bacterial keratitis.

OBJECTIVE: The study aimed to profile and quantify tear metabolites associated with bacterial keratitis using both untargeted and targeted metabolomic platforms. METHODS: Untargeted metabolomic analysis using liquid-chromatography-Q Exactive-HF mass-spectrometry explored tear metabolites significantly associated with bacterial keratitis (n = 6) compared to healthy participants (n = 6). Differential statistics and principal component analysis determined meaningful metabolite differences between cases and controls. Purines and nucleosides were further quantified and compared between 15 cases and 15 controls in the targeted metabolomic platform using TSQ quantum access triple quadrupole mass spectrometry. Compound quantification was done by plotting the calibration curves and the difference in the compound levels was evaluated using the Wilcoxon rank-sum test. RESULTS: In the untargeted analysis, 49 tear metabolites (27 upregulated and 22 downregulated) were differentially expressed between cases and controls. The untargeted analysis indicated that the purine metabolism pathway was the most affected by bacterial keratitis. Metabolite quantification in the targeted analysis further confirmed the upregulation of xanthine (P = 0.02) and downregulation of adenine (P < 0.0001), adenosine (P < 0.0001) and cytidine (P < 0.0001) in the tears of participants with bacterial keratitis compared to that of healthy participants. CONCLUSIONS: Bacterial keratitis significantly changes the tear metabolite profile, including five major compound classes such as indoles, amino acids, nucleosides, carbohydrates, and steroids. This study also indicates that tear fluids can be used to map the metabolic pathways and uncover metabolic markers associated with bacterial keratitis. Conceivably, the inhibition of nucleoside synthesis may contribute to the pathophysiology of bacterial keratitis because nucleosides are required for maintaining cellular energy homeostasis and immune adaptability.

Agreement between Lea Symbols and Patti Pics visual acuity in children and adults.

BACKGROUND: Patti Pics (PP) and Lea Symbols (LS) are commonly used by eye care practitioners worldwide. Although the relationship between the two tests is fairly well understood, the availability of different chart designs (single optotypes, multiple optotypes, multiple optotypes with crowding box) merits futher understanding. The purpose of this study is to explore the agreement between the acuity measures obtained with Patti Pics and Lea Symbols in children and adults and compare their performance with the Sloan Letter (SL) chart in adults. METHODS: Monocular visual acuity was obtained from ninety-three 3 to 5-year-old children using Patti Pics and Lea Symbols. Acuities were also obtained from 113 adults using the same tests under identical conditions. Acuity results obtained with the pediatric tests were compared with the gold-standard Sloan Letter chart in adults. The Bland-Altman method was implemented to compare the level of agreement between tests. RESULTS: Patti Pics yielded worse visual acuity than the Lea Symbols by approximately half a logMAR line in both children (mean difference: -0.07 ± 0.07 logMAR, p <0.01) and adults (Mean difference: -0.05 ± 0.06 logMAR, p <0.01). The 95% limits of agreement between Lea Symbol acuity and Patti pics acuity in children was ± 0.14 logMAR. Mean difference between the Sloan Letter chart and Lea Symbols acuity was not statistically significant (p = 0.08) in adults but the difference was statistically significant between PP and SL (p<0.001). The 95% limits of agreement between LS and SL and between PP and SL was ± 0.19 logMAR and ± 0.22 logMAR, respectively. CONCLUSION: Patti Pics consistently underestimated visual acuity as compared to Lea Symbols both in children and adults although the differences were not clinically significant. The LS and PP did not yield clinically significant differences in acuities when compared with Sloan letters in adults.

Assessment of genotypes, endosymbionts and clinical characteristics of Acanthamoeba recovered from ocular infection.

INTRODUCTION: Acanthamoeba is an emerging pathogen, infamous for its resilience against antiprotozoal compounds, disinfectants and harsh environments. It is known to cause keratitis, a sight-threatening, painful and difficult to treat corneal infection which is often reported among contact lens wearers and patients with ocular trauma. Acanthamoeba comprises over 24 species and currently 23 genotypes (T1-T23) have been identified. AIMS: This retrospective study was designed to examine the Acanthamoeba species and genotypes recovered from patients with Acanthamoeba keratitis (AK), determine the presence of endosymbionts in ocular isolates of Acanthamoeba and review the clinical presentations. METHODOLOGY: Thirteen culture-confirmed AK patients treated in a tertiary eye care facility in Hyderabad, India from February to October 2020 were included in this study. The clinical manifestations, medications and visual outcomes of all patients were obtained from medical records. The Acanthamoeba isolates were identified by sequencing the ribosomal nuclear subunit (rns) gene. Acanthamoeba isolates were assessed for the presence of bacterial or fungal endosymbionts using molecular assays, PCR and fluorescence in situ hybridization (FISH). RESULTS: The mean age of the patients was 33 years (SD ± 17.4; 95% CI 22.5 to 43.5 years). Six (46.2%) cases had AK associated risk factors; four patients had ocular trauma and two were contact lens wearers. A. culbertsoni (6/13, 46.2%) was the most common species, followed by A. polyphaga and A. triangularis. Most of the isolates (12/13) belonged to genotype T4 and one was a T12; three sub-clusters T4A, T4B, and T4F were identified within the T4 genotype. There was no significant association between Acanthamoeba types and clinical outcomes. Eight (61.5%) isolates harboured intracellular bacteria and one contained Malassezia restricta. The presence of intracellular microbes was associated with a higher proportion of stromal infiltrates (88.9%, 8/9), epithelial defect (55.6%, 5/9) and hypopyon (55.6%, 5/9) compared to 50% (2/4), 25% (1/4) and 25% (1/4) AK cases without intracellular microbes, respectively. CONCLUSIONS: Genotype T4 was the predominant isolate in southern India. This is the second report of T12 genotype identified from AK patient in India, which is rarely reported worldwide. The majority of the Acanthamoeba clinical isolates in this study harboured intracellular microbes, which may impact clinical characteristics of AK.

Understanding clinical and immunological features associated with Pseudomonas and Staphylococcus keratitis.

Pseudomonas aeruginosa and Staphylococcus aureus are the two dominant Gram-negative and -positive species, respectively, isolated from patients with contact lens-related bacterial keratitis. The clinical features of bacterial keratitis vary, such that timely differential diagnosis can be challenging, which may cause a delay in diagnosis resulting in poorer outcome. This review aims to explore the current understanding of clinical and immunological features associated with contact lens-related P. aeruginosa and S. aureus keratitis based on currently available evidence. Firstly, the review characterises contact lens-related P. aeruginosa and S. aureus keratitis, based on clinical features and prognostic factors. Secondly, the review describes the primary immune response associated with a bacterial infection in in-vivo non-scratch contact lens-wearing animal models, colonised by bacteria on contact lens and topical administration of bacteria on the cornea. Finally, the review discusses the role of macrophage inflammatory protein-2 (MIP-2) and intercellular adhesion molecule (ICAM-1) in neutrophil recruitment based on both in-vivo scratch models of bacterial keratitis and bacterial challenged in cell culture models.

Flash VEP in clinically stable pre-term and full-term infants.

PURPOSE: Pre-term infants are at risk of abnormal visual development that can range from subtle to severe. The aim of this study was to compare flash VEPs in clinically stable pre-term and full-term infants at 6 months of age. METHODS: Twenty-five pre-term and 25 full-term infants underwent flash VEP testing at the age of 6 months. Monocular VEPs were recorded using flash goggles on a RETIscan system under normal sleeping conditions. Amplitude and peak time responses of the P2 component in the two eyes were averaged and compared between the two groups. Multiple regression analyses were performed to assess the relationship of the P2 responses with birth weight (BW) and gestational age (GA). RESULTS: At 6 months corrected age, pre-term infants had significantly delayed P2 peak times than full-term infants (mean difference: 10.88 [95% CI 4.00-17.76] ms, p = 0.005). Pre-term infants also showed significantly reduced P2 amplitudes as compared to full-term infants (mean difference: 2.36 [0.83-3.89] µV, p = 0.003). Although the regression model with GA and BW as fixed factors explained 20% of the variance in the P2 peak time (F2,47 = 5.98, p = .0045), only GA showed a significant negative relationship (ß = -2.66, p = .003). Neither GA (ß = 0.21, p = .28) nor BW (ß = 0.001, p = .32) showed any relationship with P2 amplitude. CONCLUSIONS: Our results demonstrate that, compared with full-term infants, clinically stable pre-term infants exhibit abnormal flash VEPs, with a delay in P2 peak time and a reduction in P2 amplitude. These findings support a potential dysfunction of the visual pathway in clinically stable pre-term infants as compared to full-term infants.

Effect of High Myopia on Optic Nerve Head by Confocal Scanning Laser Ophthalmoscopy in Nepalese Eyes.

PURPOSE: To compare parameters of confocal scanning laser ophthalmoscopy (Heidelberg Retinal Tomograph [HRT] II) in high myopia with age- and sex-matched emmetropes. METHODS: A hospital-based cross-sectional study was conducted among Nepalese subjects aged 18 to 35 years at BP Koirala Lions Centre for Ophthalmic Studies, Institute of Medicine, Maharajgunj, Kathmandu from November 2015 to October 2016. Fifty consecutive subjects with high myopia (spherical equivalent ranging from -6.00 to -12.00 diopters) and age- and sex-matched emmetropic subjects were enrolled for comparison. Correlations between disc area and other HRT parameters, asymmetry between the right and left eyes, and comparisons between male and female subjects in both high myopic and emmetropic groups were evaluated. RESULTS: Disc area was not significantly (p = 0.11) larger in high myopic eyes than in emmetropic eyes. HRT parameters in highly myopic eyes involved smaller cup parameters and greater rim parameters compared with emmetropic eyes. Disc area was found to be significantly positively correlated with inter disc parameters and significantly negatively correlated with rim to disc area ratio in the high myopia group. Disc area and other intra-disc parameters showed significant correlations between right and left eyes in both high myopia and emmetropia, and no significant differences between males and females from a Nepalese population. CONCLUSIONS: Characteristics of HRT parameters in high myopic eyes involved smaller cup parameters and greater rim parameters compared with emmetropic eyes in a Nepalese population. The effect of disc area on HRT parameters differed significantly only in height variation contour by emmetropic eyes.

Awareness of Eye Health and Diseases among the Population of the Hilly Region of Nepal.

PURPOSE: To collect information regarding awareness and knowledge of eye health and diseases among the population of the hilly region of Nepal. METHODS: In a population-based survey, 1834 participants were enrolled in to the study. Field procedures included the development of a survey questionnaire, field orientation, pretesting, and household data collection. Association between knowledge of eye diseases was derived using the Chi-square test and odds ratios with a 95% confidence interval. A P value of ≤0.05 was considered significant. RESULTS: Most participants were 31-40 years old (33.4%), female (51.1%), of upper caste (43.4%), Hindus (83.3%), received secondary level of education (34.4%), and involved in agriculture (48.6%). Awareness of cataract, night blindness, glaucoma, strabismus, and systemic diseases was 74.6%, 53.4%, 17.4%, 70.8%, and 46.5%, respectively. Knowledge regarding these diseases among those aware was 39.1%, 72.2%, 50.9%, and 92.3%, respectively. Awareness of cataract was significantly higher (88.4%) among higher caste groups (P < 0.001; OR, 4.29; 95% CI, 3.34-5.54), followed by business as an occupation (88.2%; P = 0.001; OR, 2.65; 95% CI, 1.44-4.9). Awareness of night blindness was significantly higher among students (72.6%; P < 0.001; OR, 2.46; 95% CI, 1.65-3.67). CONCLUSION: There was a general lack of awareness and knowledge of common eye diseases. Improved awareness and knowledge are required for the prevention, early treatment, and access to eye care.

Visual symptoms associated with refractive errors among Thangka artists of Kathmandu valley.

BACKGROUND: Prolong near work, especially among people with uncorrected refractive error is considered a potential source of visual symptoms. The present study aims to determine the visual symptoms and the association of those with refractive errors among Thangka artists. METHODS: In a descriptive cross-sectional study, 242 (46.1%) participants of 525 thangka artists examined, with age ranged between 16 years to 39 years which comprised of 112 participants with significant refractive errors and 130 absolutely emmetropic participants, were enrolled from six Thangka painting schools. The visual symptoms were assessed using a structured questionnaire consisting of nine items and scoring from 0 to 6 consecutive scales. The eye examination included detailed anterior and posterior segment examination, objective and subjective refraction, and assessment of heterophoria, vergence and accommodation. Symptoms were presented in percentage and median. Variation in distribution of participants and symptoms was analysed using the Kruskal Wallis test for mean, and the correlation with the Pearson correlation coefficient. A significance level of 0.05 was applied for 95% confidence interval. The majority of participants (65.1%) among refractive error group (REG) were above the age of 30 years, with a male predominance (61.6%), compared to the participants in the normal cohort group (NCG), where majority of them (72.3%) were below 30 years of age (72.3%) and female (51.5%). RESULT: Overall, the visual symptoms are high among Thangka artists. However, blurred vision (p = 0.003) and dry eye (p = 0.004) are higher among the REG than the NCG. Females have slightly higher symptoms than males. Most of the symptoms, such as sore/aching eye (p = 0.003), feeling dry (p = 0.005) and blurred vision (p = 0.02) are significantly associated with astigmatism. CONCLUSION: Thangka artists present with significant proportion of refractive error and visual symptoms, especially among females. The most commonly reported symptoms are blurred vision, dry eye and watering of the eye. The visual symptoms are more correlated with astigmatism.

Ocular morbidity among porters at high altitudes.

INTRODUCTION: High altitude, often characterized by settings over 2400m, can be detrimental to the human body and pose a significant risk to ocular health. Reports concerning various ocular morbidities occurring as a consequence of high altitude are limited in the current literature. OBJECTIVES: This study was aimed at evaluating the ocular health of porters working at high altitudesof Himalayas in Nepal. MATERIALS AND METHODS: A mobile eye clinic was set up in Ghat and patient data were collected from its out- patient unit by a team of seven optometrists which was run for five days. Ghat is a small village in north-eastern Nepal, located at 2860 m altitude. Travellers walking through the trekking route were invited to get their eyes checked at the clinic. Comprehensive ocular examinations were performed, including visual acuities, objective and subjective refraction, anterior and posterior segment evaluations, and intraocular pressure measurements; blood pressure and blood glucose levels were also measured as required. Ocular therapeutics, prescription glasses, sunglasses and ocular health referrals were provided free of cost as necessary. A total of 1890 people visited the eye clinic, among which 57.4% (n=1084) were porters. CONCLUSIONS: Almost half of the porters had an ocular morbidity. Correctable refractive error was most prevalent, with other ocular health-related complications, including dry eye disease, infectious disorders, glaucoma and cataract. Proper provision of regular and effective eye care services should be made more available for those residing at these high altitudes in Nepal.

Macular thickness and macular volume measurements using spectral domain optical coherence tomography in normal Nepalese eyes.

PURPOSE: To record the normative values for macular thickness and macular volume in normal Nepalese eyes. METHODS: In all, 126 eyes of 63 emmetropic subjects (mean age: 21.17±6.76 years; range: 10-37 years) were assessed for macular thickness and macular volume, using spectral domain-optical coherence tomography over 6×6 mm(2) in the posterior pole. A fast macular thickness protocol was employed. Statistics such as the mean, median, standard deviation, percentiles, and range were used, while a P-value was set at 0.05 to test significance. RESULTS: Average macular thickness and total macular volume were larger in males compared to females. With each year of increasing age, these variables decreased by 0.556 µm and 0.0156 mm(3) for average macular thickness and total macular volume, respectively. The macular thickness was greatest in the inner superior section and lowest at the center of the fovea. The volume was greatest in the outer nasal section and thinnest in the fovea. The central subfield thickness (r=-0.243, P=0.055) and foveal volume (r=0.216, P=0.09) did not correlate with age. CONCLUSION: Males and females differ significantly with regard to macular thickness and macular volume measurements. Reports by other studies that the increase in axial length reduced thickness and volume, were negated by this study which found a positive correlation among axial length, thickness, and volume.

Topographic corneal changes in children with vernal keratoconjunctivitis: A report from Kathmandu, Nepal.

PURPOSE: The present study was conducted to determine corneal topographic characteristics of children with vernal keratoconjunctivitis (VKC) and compare the corneal topographic indices in VKC subjects with normal subjects MATERIAL AND METHOD: In the hospital based comparative study, 115 consecutive subjects with VKC and 102 age and sex matched normal subjects were selected for the videokeratography with NIDEK ophthalmic operating system. Keratoconus-like topography was determined based on the expert classifier system. Other assessments included visual acuity testing with LogMAR chart, slit lamp biomicroscopy, dilated fundus examination, measurement of central corneal thickness and intraocular pressure. Topographic indices were analyzed and compared using unpaired t-test among different groups. Sensitivity and specificity was estimated by the ROC curve. RESULT: Among 115 subjects with VKC, males comprised of 86 subjects (66.1%) and mean age of presentation was 10.9 (SD 4.9) years with mixed VKC in 56.5%. Keratoconus-like topography was present in 13 subjects (11.3%). The keratoconus predictiv index (sensitivity 92.3%, specificity 98.5%), the opposite sectoral index (sensitivity 84.6%; specificity 93.2%), the differential sectoral index (sensitivity 92.3%; specificity 90.8%) were found to be signficantly associated with VKC subjects having keratoconus-like topography. CONCLUSION: A high prevalence of keratoconus-like topography was observed in patients with VKC.

Phlyctenular keratoconjunctivitis among children in the tertiary eye hospital of Kathmandu, Nepal.

BACKGROUND: This study was conducted to determine clinical profile and etiological factors for phlyctenular keratoconjunctivitis (PKC) in our patients. MATERIALS AND METHODS: In the descriptive study, 50 pediatric cases of PKC were enrolled into the study from outpatient department of BP Koirala Lions Center for Ophthalmic Studies between August 2011 and August 2012. The age, sex, exposure to tuberculosis, ocular symptoms, and systemic complaints were recorded. Morphological description of PKC such as number, type, location and scars HISTORY and number of recurrence was also noted. The conjunctival swab was taken from all patients and sent for microbiological examination. Report of systemic involvement, worm infestation was also noted. Mantoux testing for possibility of tuberculosis was also performed. RESULTS: PKC was detected in 59 eyes of 50 children having mean age of 8.0 ± 6.2 years including 54% males, unilateral involvement in 82%, the limbal involvement in 52% and multiple PKC in 34% children. Associated ocular disorder was blepharitis in 12 (24%) children. Conjunctival swab and culture revealed Staphylococcus infection in 10 (20%) children. Of eight recurrent cases, two had urinary tract infection managed with systemic antibiotics, three had parasitic infestation treated with antihelmentics, one had mantoux positive without having evidence of tuberculosis and two cases had blepharitis as a local factor. CONCLUSIONS: PKC is mostly presented as unilateral disorder of conjunctiva. PKC is associated with blepharitis, Staphylococcus infection, worm infestation and systemic infection.

Retinal nerve fiber layer thickness in glaucomatous Nepalese eyes and its relation with visual field sensitivity.

BACKGROUND: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous Nepalese eyes using spectral domain optical coherence tomography (SD-OCT) and study its relationship with visual field sensitivity. METHODS: A total of 120 eyes comprising primary open angle glaucoma (POAG), glaucoma suspects (GS), normal tension glaucoma (NTG) and healthy subjects (n=30 cases in each group) underwent a complete ophthalmic examination, including optic nerve head (ONH) evaluation and standard automated perimetry (SAP). RNFL thickness measurements around the optic disk were taken with circular spectral domain optical coherence tomography (SD-OCT) scans. Analysis of variance (ANOVA) was used for comparison of RNFL parameters among various study groups. The relationship of RNFL parameters with visual field (VF) global indices was evaluated with regression analysis. RESULTS: The mean pRNFL thickness was significantly less in the POAG (64.30±14.45µm, p<0.01), NTG (85.43±9.79µm, p<0.001) and GS (102.0±9.37µm, p<0.001) groups than in the healthy group (109.8±8.32µm). The RNFL was significantly thinner across all quadrants in all study group pairs (p<0.05) except for normal vs. GS (only superior and inferior quadrant, significant). Linear regression plots with RNFL thickness as a predictor of MD and LV demonstrated a strong and statistically significant degree of determination in the POAG group (R(2)=0.203 and 0.175, p=0.013 and 0.021). CONCLUSION: The RNFL thickness measurements with SD-OCT are lower in glaucomatous eyes as compared to age-matched GS and normal eyes in the Nepalese population. A high resolution SD-OCT could aid significantly in the early diagnosis of glaucoma in Nepal.

Ocular morbidity among street children in Kathmandu Valley.

PURPOSE: Prevalence of ocular morbidity among street children is largely unknown. The present study was carried out to determine the prevalence of ocular morbidity among street children in the Kathmandu Valley. METHODS: A cross-sectional study consisting of an eye examination program among 569 street children aged younger than 18 years was conducted from March 2013 to February 2014. Children were included from 11 safe houses of 6 non-governmental organizations and an independent eye camp. Eye examination included visual acuity testing, anterior segment and posterior segment examination, retinoscopy and refraction, cover test, convergence, accommodation and color vision tests. Chi-square test was used to analyze the association of ocular morbidity with age, sex and living conditions. RESULTS: The majority of children (43.8%) were in the age group of 12-15 years, and the male to female ratio was 3.9:1. Uncorrected and best-corrected visual acuity ≥6/9 in at least one eye was found in 89.8% and 98.4% of children, respectively. Total ocular morbidity was observed at 31.6%. The most common types of ocular morbidity were conjunctivitis (11.0%) and refractive error (11.6%). Ocular morbidity was more common in children over 15 years of age (40.9%; p < 0.01; odds ratio 1.8). CONCLUSIONS: Ocular infection and refractive error represent the most common ocular morbidities in street children in the Kathmandu Valley.

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.

Ocular morbidity among the children of squatter settlements in Kathmandu.

PURPOSE: To determine the prevalence of ocular morbidity and refractive error among the children of the squatter settlements in Kathmandu. METHODS: A cross-sectional study was carried out at five squatter settlement areas at Kathmandu, including 366 children younger than 16 years. Detailed eye examination included the visual acuity testing, cycloplegic refraction, binocular vision assessment, anterior segment examination, and posterior segment examination. Variations in age, sex, and ethnic distribution of the study population were analyzed through analysis of variance. Pearson χ test with Yate correction was used to analyze different types of ocular morbidity. Pearson correlation coefficient test was performed to correlate refractive error in the right eye and the left eye. RESULTS: Majority of children (28.9%) belonged to the age group 8 to 10 years, and most of them belonged to the Manohara settlement area (40.2%). Male-female ratio was 0.7. Uncorrected and best-corrected visual acuity of better than or equal to 6/9 in at least one eye was found in 87.9% and 99.0% children, respectively. Total ocular morbidity was observed in 33.7%. The common type of ocular morbidity was conjunctivitis (11.2%), refractive error (9.0%), and blepharitis (5.4%). Ocular morbidity was common in infants (57.9%; p = 0.043; odds ratio, 2.8) and 14- to 15-year-old children (52.8%; p = 0.002; odds ratio, 2.5). CONCLUSIONS: Ocular infection and refractive error represent the common ocular morbidity in children living in squatter settlements.

Visual status and ocular morbidity in older adults living in residential care.

BACKGROUND: The frequency of visual impairment and blindness increases with age and is more prevalent among older adults living in residential care centers. The main aim of this study was to assess the visual status and determine the prevalence and major causes of visual impairment and blindness among the older adults living in residential care centers of Kathmandu Valley, Nepal. METHODS: A cross-sectional study was conducted on 385 residents of 60 years or older residing in seven residential care centers of Kathmandu Valley. Presenting distance visual acuity was assessed in each eye with a Snellen chart at 6-m distance in non-standardized outdoor illumination. Objective and subjective refractions were performed and the best-corrected distance visual acuity was considered in the better eye. Near acuity was assessed binocularly with The Lighthouse Near Acuity Card. Complete anterior and posterior segment examination was carried out. RESULTS: The mean age of residents was 74.34 ± 8.19 years. The majority was female residents (78.2 %). The prevalence of visual impairment and blindness was 43.70 %. Adequate refractive correction could alone reduce the prevalence of visual impairment and blindness by 15.40 %. Cataract was the leading cause of visual impairment and blindness, which was followed by age-related macular degeneration, corneal opacity, glaucoma, and macular scar. CONCLUSIONS: The prevalence of visual impairment and blindness is significant among the older adults living in residential care centers. The frequency of visual impairment and blindness can be prevented by adequate refractive correction, frequent eye examination, and appropriate high use of cataract surgery.

Duane's retraction syndrome: a retrospective review from Kathmandu, Nepal.

PURPOSE: The aim was to study the clinical characteristics of Duane's retraction syndrome (DRS) in Nepalese patients. METHOD: Medical records from 52 cases of DRS from May 2003 to April 2010 were retrospectively reviewed for age, gender, laterality and clinical characteristics. Forty-one case records (78.8 per cent) that had complete clinical findings were considered for further evaluation. Examination included visual acuity by Snellen chart, refraction, associated horizontal and vertical strabismus in primary gaze, upshoot and downshoot on attempted adduction, binocular vision assessed with the Worth four-dot test on adopted gaze and stereopsis examined with the Titmus stereo test. RESULTS: DRS type I was the most common type observed in 73.2 per cent of cases, followed by DRS type II (14.6 per cent) and DRS type III (12.2 per cent). It was more common in female patients (58.5 per cent) than male patients (χ(2) = 4.6, df = 1, p = 0.03). DRS was more common in the left eye (68.3 per cent) than the right eye and unilaterally present in 95.1 per cent of subjects. In primary gaze, orthotropia (41.5 per cent) was more common than exotropia (34.1 per cent) and esotropia (24.4 per cent) and vertical strabismus was present in 24.4 per cent of subjects. Upshoot and downshoot on attempted adduction was seen in 14.6 and 9.8 per cent, respectively. Binocular single vision was present in 68.3 per cent of subjects by Worth four-dot test at near. Stereopsis of 3,000 seconds of arc was present in 9.8 per cent, 100 to 200 seconds of arc in 14.6 per cent and 40 to 60 seconds of arc in 43.9 per cent with the Titmus stereo test. CONCLUSION: DRS is more common in female patients and the left eye. DRS type I is the most common type.