Browsing by Author "Dahal, HN"
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Publication Pattern and Prevalence of Refractive Error and Secondary Visual Impairment in Patients Attending a Tertiary Hospital in Dhulikhel, Nepal(Kathmandu University, 2018) Kaiti, R; Pradhan, A; Dahal, HN; Shrestha, PABSTRACT Background Uncorrected refractive error is one of the most important causes of visual impairment worldwide. Objective To ascertain the pattern and prevalence of refractive error and secondary visual impairment in subjects attending Ophthalmology department. Method A prospective hospital-based study was designed where presenting visual acuity, age of presentation, refractive status, best corrected visual acuity and status of visual impairment were assessed in participants, ages ranging from 3-39 years presenting to the Ophthalmology department of Dhulikhel Hospital, Kathmandu University Hospital. History of use of spectacle was noted and participants were categorized into different visual impairment categories as per their presenting visual acuity. Result Out of a total of 4500 total clients examined during the study period, 388 (8.62%) had refractive error where 219 (56.44%) were females and 169 (43.56%) were males. Mean age at presentation was 22.70±7.69 years (range, 3-39 years). Astigmatism was the most common subtype seen in 373 eyes (48.06%), followed by myopia (366 eyes, 47.16%) and hypermetropia (31 eyes, 4.0%). Only 40.50% subjects who required refractive correction were using spectacle. 62.37% (242 clients) had some of visual impairment during their presentation. There was statistically significant improvement in visual acuity after refractive correction (p=0.00). Conclusion Uncorrected refractive error is one of the most important causes of visual impairment. Lack of awareness, infrequent ocular examination and lack of community or preschool vision screening were the main causes for the late presentation and significant visual impairment associated with the condition. Social stigma, economical limitation and negative counseling and attitudes about spectacle wear were primary factors behind the unsatisfactory spectacle use. KEY WORDS Astigmatism, Refractive correction, Refractive error, Visual impairmentPublication Prevalence and types of corneal astigmatism in patients undergoing cataract surgery(Institute of Medicine, 2017) Chaudhary, M; Dahal, HNAbstract Introduction: Cataract surgery is one of the most commonly performed ophthalmic surgical procedures worldwide, with a high rate of successful and rapid anatomical and functional visual recovery. Goal of cataract surgery is to achieve a desirable induction of refractive outcome with minimal astigmatism after surgery. This brings to interest the question of influence of preoperative and surgically induced corneal astigmatism on the final postoperative unaided visual acuity. Pre-existing corneal astigmatism is an important limiting factor for optimal results of cataract surgery in a significant number of patients. It has been estimated that 15% to 29% of patients with cataract have more than 1.50 dioptres (D) of pre-existing astigmatism. Methods: Prospective study was carried out to investigate the prevalence and pattern of pre-existing corneal astigmatism in patients undergoing cataract surgery at B.P. Koirala Lions Center for Ophthalmic Studies, T.U. Teaching Hospital for a period of 2 years. All patients underwent complete ophthalmic examination including visual acuity, refraction, slit lamp examination, applanation tonometry and dilated fundus evaluation, biometry and ultrasound B-scan examination. Corneal astigmatism was measured by Keratometer at least two times for each patient. Astigmatism was calculated from dioptric difference between vertical reading and horizontal reading. With the rule (WTR) astigmatism was considered when steep meridian was at 900 ± 300. Against the rule (ATR) astigmatism was considered when steep meridian was at 1800 ± 300. Results: Study included 225 eyes of 185 subjects, out of which 38.7% were male eyes and 61.3% were female eyes. The mean age of the subjects was 64.45±12.89 years. Mean amount of corneal astigmatism in our study was 0.84±0.80 D. 16.9% had no significant corneal astigmatism while 65.3% had corneal astigmatism between 0.25 and 1.50 diopter and 17.8% had corneal astigmatism of 1.50D or higher. With-the-rule astigmatism (axis of correcting cylinder 180±30 degrees) was present in 44.4% eyes, 40.04% of the eyes had against-the-rule (ATR) astigmatism (correcting minus cylinder 90±30 degrees), and 12.9% of the eyes had oblique astigmatism. Conclusion: Approximately two thirds of pre-operative cataract patients had 1D or less astigmatism. Corneal astigmatism increases with age. Hence, it is important to analyze the magnitude and pattern of pre-existing corneal astigmatism in aging population due to higher demand for improved vision and use of suitable methods for best visual results. Keywords: Cataract, corneal astigmatism, Keratometer, with the rule, against the rule