Medical Hypothesis, Discovery & Innovation in Optometry

Background: Cataract surgery in patients with diabetes is indicated either to improve visual acuity or to allow assessment and treatment of fundus changes. We aimed to document the effects of phacoemulsification on the corneal endothelium in patients with or without diabetes.
Methods: This comparative, prospective, non-randomized controlled interventional study was conducted in patients with visually significant immature senile cataracts in the ophthalmology department at Sohag University Hospital between January 2018 and December 2020. The following data were recorded: corrected distance visual acuity, keratometry readings, refraction, slit lamp measurements, specular microscopy results, and biometry data. Changes in corneal parameters were documented preoperatively and at 1, 3, and 6 months postoperatively using specular microscopy.
Results: Sixty-four eyes of 64 patients with visually significant senile cataracts were included (32 eyes in the diabetic group and 32 eyes in the non-diabetic control group). We found greater mean endothelial cell loss in the non-diabetic group (179 cells/mm2; 6.4%) than in the diabetic group (134 cells/mm2; 4.8%) at 3 months postoperatively, yet the difference was not significant. The difference could be explained by the higher mean cumulative dissipated energy (CDE) used in the non-diabetic group (5.37 J) than in the diabetic group (4.68 J), although the difference was also not significant. Moreover, we found significantly higher coefficient of variation (CV) in the non-diabetic group than in the diabetic group at 1, 3, and 6 months postoperatively (P = 0.03, P = 0.02, and P = 0.008, respectively).
Conclusions: Endothelial cell density was directly related to the CDE of phacoemulsification and not to diabetes. CV was significantly higher in the non-diabetic group than in the diabetic group. Future studies with a larger sample size, longer follow-up, and more diabetic subgroups with different levels of glycemic control are warranted to verify our conclusions.
Keywords: phacoemulsification, intraocular, CDE, cumulative dissipated energy, cataract surgery, diabetes mellitus, corneal endothelium, diabetic, non-diabetic, specular microscopy, endothelial cell density, coefficient of variation, CV, central corneal thickness, CCT

Background: Glaucoma is a progressive, irreversible optic neuropathy results in serious vision loss and blindness.  The aim of this review was to summarize key concepts of last decade POAG pharmaceutical treatment trials.
Methods: Search in PudMed/MEDLINE and clinicaltrials.gov from 2010 January 1, to 2020 February 28, yielded 77 and 120 papers respectively, using the key words ‘POAG’ and Ocular ‘Topical Therapeutics’.
Results: Thirty-three records were compatible with our inclusion criteria. Pharmaceutical treatment is a common intervention in POAG for lowering IOP.  Prostaglandin (PG) analogues are most commonly recommended as initial medical therapy, which administrated either as a monotherapy or in combination with other IOP-lowering classes of medications. Alternative therapies such as β-blockers, α-2 adrenergic receptor agonist, and topical carbonic anhydrase inhibitors have been used in combination or as a monotherapy. Rho-kinase inhibitors such as netarsudil 0.02%, AR-13324 0.02% and ripasudil are new IOP lowering medications. Despite IOP reduction, there is a significant number of patients with POAG that may experience progression, and the risk of blindness over long period of time is considerable.
Conclusions: Clinical trials on pharmaceutical treatment of POAG found medical treatment effective and safe. In addition, the new novel Rho-kinase inhibitors that have shown significant IOP reduction. The new fixed combinations have shown significant reductions in IOP. Considering POAG as an irreversible cause of vision loss, if not treated early, and early diagnosis has been made, a significant number of patients are likely to progress and the risk of blindness over time is considerable. 
Keywords: primary open angle glaucoma, intervention study, randomized clinical trials, RCTs, drug therapies, pharmaceutical treatment, medical therapy, prostaglandin analogues, beta adrenergic blockers, α-2 adrenergic receptor agonist, carbonic anhydrase inhibitor, Rho-kinase inhibitor
 

Background: The prevalence of hearing impairment in Nepal is 16.5%, affecting approximately 2.71 million people. Deaf children are visually dependent, and even a mild refractive error may cause visual discomfort. The goal of this study was to determine the need for vision screenings in schools for the hearing impaired in Biratnagar, Nepal.
Method: A cross-sectional study was conducted with permission from Birat Deaf Secondary School, Biratnagar, Nepal. A total of 130 hearing-impaired students were examined. Non-invasive, comprehensive optometric examinations were performed to detect visual disorders. When a more detailed evaluation was needed, the students were referred to Biratnagar Eye Hospital.
Results: Of the 130 hearing-impaired students, 58 (44.6%) were male and 72 (55.4%) were female. The mean ± standard deviation of age was 16.03 ± 3.8 years (range 6–25 years). Twenty-one (16.1%) students had refractive errors: 13 (10%) had myopia, 7 (5.4%) had hyperopia, and 1 (0.8%) had anisometropia. In the cover test, 88 (67.7%) had orthophoria, 19 (14.6%) had exophoria, 11 (8.5%) had esophoria, 5 (3.85%) had exotropia, and 3 (2.3%) had esotropia. Cover tests were not performed in 4 (3.1%) students, as they were unable to fixate due to nystagmus or decreased vision. On ocular examination, 20 (15.3%) students had anterior segment abnormalities, including lid abnormality, conjunctivitis, Bitot’s spots, pterygium, corneal opacity, and lenticular opacity. Posterior segment or retinal abnormalities were found in four students with one having Usher syndrome. Color vision defects, nystagmus, and amblyopia were found in 8 (6.1%), 2 (1.5 %), and 1 (0.8%), respectively.
Conclusion: The findings of the present study reflect the need of periodic vision screenings in schools for the hearing impaired in Nepal. These children are at a high risk of vision impairment. 
Keywords: vision screening, refractive error, strabismus, hearing impairment, student, screening, myopia, hyperopia, anisometropia, strabismus, Nepal

Background: This study aimed to compare the impact of visual function and the presence and number of aiming lines on golf putting alignment between beginner and expert golfers.
Methods: In this prospective comparative study, 43 participants with a mean ± standard deviation (SD) of corrected distance binocular visual acuity of –0.07 ± 0.74 logarithm of the minimum angle of resolution, who knew their average golf scores, were divided into beginner and expert golfers. Six visual function tests were conducted to assess heterotropia, dominant eye, verification of current spectacles, static visual acuity, stereopsis, and fixation disparity. At the putting distances of 1.5 m and 3 m, alignment errors were measured five times each, using golf balls with 1 and 3 aiming line(s) and putters with 1 and 3 aiming line(s).
Results: The mean age ± SD of the participants was 48.33 ± 10.07 years. The accuracy of ball alignment was not affected by the carrier or number of aiming lines, but the putter alignment was higher for the 3-lines putter than for the 1-line putter (P < 0.05). When the number and shape of the aiming line were the same for both the ball and putter, the aiming accuracy was found to be higher. In both stereopsis and fixation disparity, the combination of putting distance and a 3-lines ball showed negative values; all other combinations showed positive values, but no statistically significant correlation was detected.
Conclusions: The accuracy of golf ball alignment did not depend on the number of aiming lines and the golfer’s carrier.
Keywords: aiming line, putting, alignment, dominant eye, sport vision, golfer, golf ball, putter
 

Background: Optic disc pit (ODP) is a rare congenital defect of the optic disc that can lead to maculopathy and gradual visual impairment. This review summarizes our current knowledge on the diagnostic and therapeutic approaches to ODP maculopathy (ODP-M) in children.
Methods: A thorough literature search was performed using the PubMed database from 1960 to 2020. An additional search was conducted using Google Scholar for completeness.
Results: ODP-M is characterized by the accumulation of subretinal and/or intraretinal fluid. The exact pathogenetic mechanisms are not fully understood, but the origin of the fluid remains unknown. Although ODP-M is more likely to occur during the third or fourth decade of life, cases of children with serous retinal detachment have been recorded. In adults, ODP-M may resolve spontaneously, but most cases require surgical intervention to prevent permanent loss of vision. Various surgical methods have been described, including pars plana vitrectomy (PPV) combined with various techniques, including laser photocoagulation, intravitreal gas injection, and macular buckling.
Conclusions: PPV remains the mainstay surgical approach for ODP-M. However, ODP-M may differ between children and adults. Children constitute a unique population of patients that require a different and probably more tailor-made approach. Detailed clinical examination, combined with a thorough analysis of retinal imaging, may improve our understanding of the background and pathophysiology of the disease and eventually provide us with new insights into the management of ODP-M in the pediatric population.
Keywords: congenital anomalies, optic disc pit, optic disc pit maculopathy, retinal imaging, surgical treatment, pars plana vitrectomy

Background: To determine the prevalence of amblyopia in schoolchildren aged 7–9 years old in Mashhad, Iran.
Methods: This was a cross-sectional, community-based study with schoolchildren aged 7–9 years old. We randomly selected 20 of 189 elementary schools (three schools per district; 10 male-segregated and 10 female-segregated schools) from a proportional combination of public schools across Mashhad. Basic vision exams were performed. If amblyopia was suspected, children underwent supplementary vision exams. The diagnostic criterion for amblyopia was a best corrected visual acuity (BCVA) in one or both eyes equal to or worse than 20/40 or an interocular difference of more than two lines in BCVA without any significant organic pathology.
Results: A total of 2831 children were included in the study. All children were examined comprehensively by an optometrist, and amblyopia was detected in 49/2831 (1.7% [95% CI, 1.22 to 2.18]). Of the 49 children with amblyopia, 20 (40.8%) were amblyopic in the right eye, nine (18.4%) in the left eye, and 20 (40.8%) in both eyes. Twenty-four (49%) were first graders, 15 (30.6%) were second graders, and 10 (20.4%) were third graders. The most prevalent subtype of functional amblyopia was anisometropic amblyopia.
Conclusions: Considering the prevalence of amblyopia among schoolchildren aged 7–9 years old (1.7%), timely detection of amblyopia through preschool screening programs is essential for early treatment or prevention of further visual impairment during childhood.
Keywords: amblyopia, prevalence, elementary school, preschool children, Iran, diagnostic screening program