Safal Khanal

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.

Visual deficits in Nepalese patients with oculocutaneous albinism

Background Albinism poses a significant threat to visual functions and causes remarkable ocular morbidity often resulting in visual disabilities. The study aimed at describing the visual status in patients with diagnosed cases of complete oculocutaneous albinism (OCA) attending to a tertiary eye hospital in Nepal. Methods This was a cross-sectional descriptive hospital-based study of all diagnosed oculocutaneous albinotic cases (16 males and 9 females; mean age of 16 years) who visited the Department of Ophthalmology at the Institute of Medicine, for ocular consultation between September 1, 2011 and December 1, 2013. Results Twenty-five cases (50 eyes) with OCA were enrolled in the study. All the participants had maximally reduced visual acuity (mean: 1.24 ± 0.50 logMAR). Myopic astigmatism was the most common refractive error (n = 17; 34%). 58% of all participants had with-the-rule astigmatism. Considering the spherical equivalent power, most of the eyes (n = 30; 60%) had myopia, with overall mean SE refractive error of −1.59 ± 5.39 D. Visual acuity improved significantly with refractive correction in place (paired sample t-test, p < 0.05). Horizontal pendular nystagmus was the most common nystagmus (n = 34 eyes; 68%). Alternating esotropia and alternating exotropia each were observed in 16% of participants who had strabismus (40% of all cases). The diaphanous iris, foveal hypoplasia and poliosis were the most consistent clinical features. Conclusion Patients with OCA present with a broad spectrum of visual deficits that impair the visual functions. Significant improvement in visual acuity following optical correction serves as an impetus to the reduction of visual disabilities in individuals with albinism.

Profile of paediatric low vision population: a retrospective study from Nepal.

Childhood blindness and low vision have become major public health problems in developing countries. The purpose of this study was to categorise the causes of visual impairment according to aetiology and provide detailed local information on visually impaired children seeking low‐vision services in a tertiary eye centre in Nepal.

Repeatability of Arterial Spin Labeling MRI in Measuring Blood Perfusion in the Human Eye: MRI of Blood Perfusion in the Human Eye

Quantifying blood perfusion in ocular tissues is challenging, partly because the majority of the blood is carried by the choroid, which is difficult to visualize because it is located between the retina and sclera.

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 (β = 0.32, R = 17.6%, P < .05) but a negative relationship between BW and astigmatism (β = -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.

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.

Evaluation of intraocular pressure estimates obtained using an iCare rebound tonometer

The aims of this study were to evaluate the intra‐ and inter‐observer repeatability of intraocular pressure (IOP) estimates obtained using an iCare rebound tonometer and to investigate the variation in IOP measurements due to positional differences in probe placement on the cornea.