Epidemiology, Microbiology, and Genetics of Contact Lens-Related and Non-Contact Lens-Related Infectious Keratitis.

ABSTRACT: Infectious keratitis is a rare but severe condition associated with a range of ocular and systemic predisposing conditions, including ocular trauma, prior surgery, surface disease, and contact lens (CL) wear. This review explores the epidemiology of infectious keratitis, specifically the differences in disease incidence and risk factors, causative organism profile and virulence characteristics and host microbiome, genetics, gene expression, proteomics, and metabolomic characteristics in CL-related and non-CL-related diseases. Differences exist in the epidemiology, demographics, causative organisms, and their virulence characteristics in CL-related and non-CL-related diseases, and there is less evidence to support differences between these groups of individuals in the ocular surface microbiome, genetics, and pathways of disease. Genetic variations, however, in the host immune profile are implicated in both the onset and severity of infectious keratitis in CL and non-CL wearers. As technologies in metabolomics, proteomics, and genomics improved to be better able to process small-volume samples from the ocular surface, there will be improved understanding of the interplay between the CL, ocular surface, host immune profile, and the microbial environment. This may result in a more personalized approach in the management of disease to reduce disease severity.

Refractive Status in Nepalese Pre-Term and Full-Term Infants Early in Life.

SIGNIFICANCE: This study suggests that pre-term infants, even without retinopathy of prematurity, are at risk for abnormal refractive development and informs the need for close monitoring of refractive error in such infants, regardless of their retinopathy of prematurity status. PURPOSE: The present study aims to investigate the refractive error trend in Nepalese pre-term infants without retinopathy of prematurity (ROP) in the first 6 months of life and explore the association of refractive error with birth weight (BW) and gestational age (GA). METHODS: Thirty-six pre-term infants without ROP and 40 full-term infants underwent cycloplegic retinoscopy at birth, term (for pre-term only), 3 months, and 6 months chronologically. Refractive status was classified into emmetropia (mean spherical equivalent refraction [SER] 0 to +3.00D), myopia (SER < 0.00D), and significant hyperopia (SER > +3.00D). Refractive parameters at various age points were compared between the pre-term and full-term infants using general linear model repeated measures ANOVA. RESULTS: At birth, the SER in the pre-term infants was +0.84 ± 1.72D; however, there was a shift toward myopia at 6 months of age (SER = -0.33 ± 1.95D). There was a significant difference in SER, astigmatism, and anisometropia between pre-term and full-term infants by 6 months of age (P < .01). Astigmatism and anisometropia showed an increasing trend with age in pre-term infants (P < .05 at 6 months) in contrast to a decreasing trend in full-term infants (P < 0.05 at 3 and 6 months). In pre-term infants, there was a statistically significant positive relationship between GA and SER (ß = 0.32, R = 17.6%, P < .05) but a negative relationship between BW and astigmatism (ß = -1.25, R = 20.6%, P < .01). CONCLUSIONS: Pre-term infants who do not develop ROP show a trend toward increasing myopia and demonstrate greater astigmatism and anisometropia than full-term infants in their first 6 months of life.

Effectiveness of measuring the central field with the Berkeley field test.

INTRODUCTION: There are several limitations of the Amsler chart as a screening tool due to its low sensitivity and high false-negative results. The Berkeley central visual field test (BCFT), which is a simple power-point presentation of a 50-point scoring system for the central 10-degree of the visual field, was devised as an alternative to the Amsler chart. OBJECTIVES: To compare the efficacy of measuring the central visual field using the Berkeley central field test (BCFT) and the Amsler grid test. MATERIALS AND METHODS: In a comparative and validity study, 30 subjects with maculopathy and 35 controls were recruited. The maculopathy subjects with the best corrected visual acuity of 20/200 or better and 2.5M for distant and near vision respectively, were included. All the subjects under went a complete eye examination where visual assessment was done using the distant and near vision Log MAR Chart. The subjects were assessed with the Amsler chart-II at a distance of 30 cm. The BCFT was used as a 50- point scoring system. The effectiveness of BCFT was compared with that of the Amsler grid regarding the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). RESULTS: Out of 65 subjects, 30 subjects had maculopathy and 35 were normal. The mean age of the 65 subjects was 49.8±9.1 years. Of the 30 subjects with maculopathy, the majority (54%) had age- related macular degeneration. The sensitivity, specificity, PPV and NPV of the Amsler grid test were found to be 80%, 100%, 100% and 87%, respectively, whereas those of the BCFT were 71%, 99%, 98% and 82% (p=0.37). CONCLUSION: The BCFT test was as good as the Amsler grid test at detecting the presence of maculopathy.

Ocular manifestations of childhood acute leukemia in a tertiiary level eye centre of Kathmandu, Nepal.

INTRODUCTION: In some instances, the understanding of the ocular manifestations in childhood leukemia is not only important to establish the diagnosis but also reflects the disease state and prognosis. OBJECTIVE: To study the ocular manifestations of childhood acute leukemia among the children attending a tertiary-level hospital in Nepal. MATERIALS AND METHODS: A cross-sectional, descriptive study was undertaken at the B.P. Koirala Lions Centre for Ophthalmic Studies (BPKLCOS) and Kanti Children Hospital (KCH), Kathmandu, over a period of one-and-a-half years. Children diagnosed with acute childhood leukemia referred to the BPKLCOS from the Oncology Unit of the KCH and the Emergency Department of the Tribhuvan University Teaching Hospital (TUTH) were included in the study, using a non-probability sampling method. RESULTS: Of the 71 cases with childhood acute leukemia, 55 (77.5%; 95% CI = 66% - 85%) had acute lymphoblastic leukemia(ALL)whereas the other 16 (23%) had acute myeloblastic leukemia (AML). Ocular involvement were seen in 33 cases (46%) and were more frequent in cases of AML as compared to those with ALL (p=0.001, OR 5.0, 95% CI= 1.4 - 17.5). Direct ocular involvement and secondary ocular involvement were observed in 12 (16.9%) and 29 (40.8%) subjects, respectively. Ocular symptoms were present in only 11 cases (15.49%). Cerebro-spinal fluid (CSF) and bone marrow examination in cases with direct ocular involvement showed 10 cases (83.3%) positive for blast cells in the CSF and 6 cases (50%) positive for blast cells in bone marrow. The most common secondary manifestation was retinal haemorrhage, seen in 23 cases (32.4%). CONCLUSION: In view of the high asymptomatic ocular involvement and the significant visual morbidity, a routine ophthalmic examination is recommended as an integral part of the medical examination in all cases of childhood acute leukemia.

Outcome of horizontal strabismus surgery and parents' satisfaction.

INTRODUCTION: A clinical audit of strabismus surgery in children in terms of functional and cosmetic outcomes helps improve the quality of services in pediatric ophthalmology. OBJECTIVE: To evaluate the outcome of strabismus surgery and assess the satisfaction of the patients' parents with respect to the surgery outcome. SUBJECTS AND METHODS: A study of an interventional series of cases that included 60 strabismic subjects was carried out. The bilateral strabismus surgery under general anesthesia was performed on all subjects using the fornix approach. The parents' understanding about strabismus and the cosmetic outcome was assessed through a set of interview questionnaires. The main outcome measures were the amount of deviation, the parents' knowledge about strabismus and their satisfaction after the intervention. RESULTS: Of the 60 subjects, 32 (53.3%) were esotropic and 28 (46.7%) exotropic. The male to female ratio was 1:1. The mean age with standard deviation was 16.6±8.5 years,with a range of 3 to 35 years. The pre- operative mean esotropia with standard deviation was 48.2±14.8 pd, with a range of 22 to 114 pd). The pre-operative mean exotropia was 57.8±14.2 pd, with a range of 25 to 90 pd). In 93.47% of the subjects, the ocular deviation after surgery reduced significantly (p=less than 0.00). After the strabismus surgery, orthophoria was achieved in 15 (25%) subjects, and with excellent cosmetics. After surgery, gross binocular single vision was attained in 39.3% of the exotropes and in 17.9% of the esotropes. Only 30% of the parents were aware about the strabismus and the treatment modalities. Nearly 90% of the parents were satisfied with the cosmetic outcome. CONCLUSION: Horizontal and bilateral strabismus has good surgical outcome with improved cosmetic acceptance.

Visual function in patients on ethambutol therapy for tuberculosis.

PURPOSE: Aim of the study was to evaluate the effects of ethambutol therapy in visual functions. METHODS: Prospective evaluation of 88 eyes of 44 patients on ethambutol therapy under Directly Observed Treatment Short-course (category I) for primary tuberculosis was done before start of ethambutol therapy and after 2 months of starting the therapy. Parameters evaluated were visual acuity with Bailey Lovie Log-MAR chart, contrast sensitivity with Pelli-Robson contrast sensitivity chart, color vision with Farnsworth D15 test, visual fields with Octopus automated perimetry, and multifocal electroretinography (ERG) with Roland-RETI scan along with anterior and posterior segments evaluation. RESULTS: No visual functional defect was noted at baseline. On follow-up, color vision, visual field parameters, and anterior and posterior segment findings were not affected in any patients. Mean visual acuity before starting therapy was 0.00±0.08 Log-MAR and after therapy was 0.08±0.18 Log-MAR. Change in visual acuity was statistically significant (p=0.004). Difference between contrast sensitivity before and after therapy was statistically highly significant both monocularly and binocularly (p<0.005 in both cases). P1 amplitudes (in terms of nV/deg(2) and µV) of ERG waves were significantly reduced and their P1 latencies were significantly increased in all the rings after ethambutol therapy (p<0.05). There was no significant change in N1 amplitudes and N1 latencies after therapy in any of the rings. CONCLUSIONS: Visual acuity, contrast sensitivity, and multifocal ERG are sensitive tests to detect ethambutol toxicity in subclinical stages and hence very useful tools for monitoring patients under ethambutol therapy for ocular toxicity.