Medical Hypothesis, Discovery & Innovation (MEHDI) Ophthalmology Journal
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Parkinson's disease and convergence insufficiency: A mini-review
Get PDFBackground: A key manifestation of Parkinson disease (PD) is visual impairment. Cognitive impairment has been found to overlap with convergence insufficiency (CI) in patients with PD and is associated with significantly greater near point convergence (NPC) distance. Difficulty in reading and diplopia were the most common symptoms of CI in PD. The prevalence of CI is greater among patients with PD. Therefore, this study aimed to assess the relationship between PD and CI.
Methods: Studies that had included data on CI, NPC, or both were selected by searching PubMed/MEDLINE and clinicaltrails.gov, without any timeline or language limitation. The following terms were used in PubMed/MEDLINE search: Clinical Trials, Parkinson Disease, and Convergence Insufficiency. For clinical trials.gov database, the terms Parkinson Disease, Convergence Insufficiency, and Completed Studies were used. Only those studies with control subjects were included. PubMed/MEDLINE search yielded 1,563 articles, but no article was found in the clinical trails.gov search. Twelve articles met the inclusion criteria, among which nine articles were selected as they had data on CI or NPC distance (cm), and PD.
Results: Overall, there were 1,563 articles; among them, 12 articles met the inclusion criteria. Nine articles were selected based on their data concerning CI or NPC distance (cm) and PD. Relative to the control group, the PD group had high CI. In addition, PD group showed increase in NPC distance than the control group.
Conclusions: These data suggest that the patients with PD had an increased likelihood of developing CI visual symptoms, and increased NPC distance than healthy controls. These findings indicate that regular eye examination is very important for patients with PD
Effects of aiming lines and visual function on the golf putting alignment
Get PDFBackground: In golf, a player hits a ball with a club, aiming to transfer the ball successively into a series of hole cups in a course consisting of 18 (or fewer) holes. 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 ± SD of age was 48.33 ± 10.07 years for study participants overall. The accuracy of ball alignment was not affected by the career 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 (all P > 0.05).
Conclusions: The accuracy of golf ball alignment did not depend on the number of aiming lines and the golfer’s career. However, the predicted putting success rate and subjective satisfaction were increased when three-line golf balls and putters were used, as compared to when one-line golf balls and putters were used
A review of recent developments in retinitis pigmentosa genetics, its clinical features, and natural course
Get PDFBackground: Retinitis pigmentosa (RP), an inherited degenerative ocular disease, is considered the most common type of retinal dystrophy. Abnormalities of the photoreceptors, particularly the rods, and of the retinal pigment epithelium, characterizes this disease. The abnormalities progress from the midperiphery to the central retina. We here reviewed the developments in RP genetics in the last decade, along with its clinical features and natural course.
Methods: The present review focused on articles in English language published between January 2008 and February 2020, and deposited in PubMed and Google Scholar databases. We searched for articles reporting on the clinical manifestations and genes related to both syndromic and non-syndromic RP. We screened and analyzed 139 articles, published in the last decade, referring to RP pathogenesis and identified, summarized, and highlighted the most significant genes implicated in either syndromic or non-syndromic RP pathogenesis, causing different clinical manifestations.
Results: Recent literature revealed that approximately 80 genes are implicated in non-syndromic RP, and 30 genes in syndromic forms, such as Usher syndrome and Bardet Biedl syndrome (BBS). Moreover, it is estimated that 27 genes are implicated in autosomal dominant RP (adRP), 55 genes in autosomal recessive RP (arRP), and 6 genes in X-linked RP (xlRP), causing different RP phenotypes. Characteristically, RHO is the most prevalent adRP- and arRP-causing gene, and RPGR the most common xlRP-causing gene. Other important genes are PRPH2, RP1, CRX, RPE65, ABCA4, CRB1, and USH2A. However, different phenotypes can also be caused by mutations in the same gene.
Conclusions: The genetic heterogeneity of RP necessitates further study to map the exact mutations that cause more severe forms of RP, and to develop and use appropriate genetic or other effective therapies in future
Non-inferiority evaluation of preservative-free latanoprost/timolol eye drops solution versus preserved latanoprost/timolol eye drops in patients with high intraocular pressure and open-angle glaucoma
Get PDFBackground: This study aimed to evaluate the non-inferiority and safety of a newly developed preservative-free (PF) multi-dose latanoprost/timolol ophthalmic solution, compared with the benzalkonium chloride (BAK)-preserved fixed combination, in patients with open-angle glaucoma and ocular hypertension.
Methods: A Phase III randomized multi-center observer-blind parallel-group clinical trial was conducted. A total of 210 adult patients (aged over 18 years) were randomly treated with the PF- or the BAK-preserved latanoprost/timolol solution once daily in the affected eye(s) for 12 weeks. Follow-up visits were scheduled at weeks 2, 6, and 12; intraocular pressure (IOP) was recorded at 8:00 AM, 12:00 PM, and 4:00 PM. The primary efficacy endpoint to prove non-inferiority was the IOP change at 8:00 AM (± 1 hour) from the baseline to the end of treatment (week 12) in the studied eye. Safety parameters were also assessed.
Results: In total, 196 patients completed the study. The pressure-lowering effect of the PF eye drops was comparable to that of the preserved formulation at all time points. Latanoprost/timolol PF formulation was non-inferior to the BAK-preserved solution as shown by the change in IOP from day 0 to week 12. The point estimate of the inter-treatment difference was 0.624 mmHg (95% CI: -0.094, 1.341). Both treatments were well-tolerated during the study, and they had similar adverse event profiles.
Conclusions: PF-latanoprost/timolol combination was found to be non-inferior to the BAK-preserved formulation based on the efficacy at all times, with similar local tolerance
Five generations of intraocular lens power calculation formulas: A review
Get PDFBackground: The effectiveness of cataract surgery depends on preoperative biometric data, including the axial length (AL), keratometric value (K), anterior chamber depth (ACD), and the accuracy of the intraocular lens power (IOLp) calculation. Five generations of IOLp calculation formulas have been developed. This review summarizes these formulas and focuses on the characteristics, advantages, and disadvantages of each. Moreover, it compares the results of several formulas used in patients with specific characteristics.
Methods: The authors searched PubMed and Google Scholar, using keyword combinations including IOLp, formulas, AL, ACD, K, and diopters (D). Two hundred recent articles that referred to IOLp calculation formulas and their effectiveness when used preoperatively in cataract surgery were retrieved and analyzed.
Results: Each generation has advantages and disadvantages for individual patients, and the selection of the most appropriate IOL differs due to patients’ different ALs. The shorter or longer the eye is, the less accurate some formulas become. Formulas such as SRK-T, Holladay, SRK-II, Hoffer, and Binkhorst II seem to have comparable efficacy. However, studies have indicated that Hoffer is superior for short eyes. In contrast, SRK/T appears to be slightly more superior for long eyes. The fifth-generation formulas also appear to be very promising.
Conclusions: Based on the available literature, there is no gold standard as yet that can be used for all patients. Instead, each patient should be managed individually depending on their particular eye characteristics
Effects of ascorbic acid on chemical and thermal corneal burns: A comprehensive literature review
Get PDFBackground: Ascorbic acid has been suggested to be effective against chemical burns. It was first tested in rabbits before being implemented in human subjects. It was proven to be useful in treatments for different conditions, such as corneal chemical and thermal burns. Herein, we aimed to review the effects of ascorbic acid in the healing of chemical and thermal corneal burns.
Methods: We performed an electronic search of English literature in MEDLINE, clinicaltrials.gov, and Google Scholar, without time constraints. Articles were selected based on inclusion and exclusion criteria, using they keywords: Corneal Burn, AND Corneal Ulcer, AND Vitamin C. This yielded 17 English language articles focused on the effect of vitamin C on chemical or thermal corneal burn-induced ulcers.
Results: The 17 eligible studies that fulfilled the inclusion criteria included three retrospective, nonrandomized, comparative studies on human subjects and 14 in vivo, laboratory-based studies on rabbits (12 studies), rats (one study), as well as guinea-pigs (one study). Most studies showed benefits in using vitamin C as a prophylactic treatment to delay or stop corneal ulcer formation after chemical or thermal corneal burn.
Conclusions: Vitamin C is a very basic, inexpensive prescription and can be used to treat corneal ulcers following a variety of corneal burns. This review highlights the necessity for conducting randomized controlled trials to investigate the prophylactic role of vitamin C and to determine its minimum required dose for the management of corneal ulcers after different types of corneal burns
Multifocal visual evoked potential for evaluation of open-angle glaucoma
Get PDFBackground: To correlate multifocal visual evoked potential (mfVEP) findings with static automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT) in eyes with primary open angle glaucoma (POAG).
Methods: This cross-sectional study included a consecutive sample of 40 eyes of 40 patients with POAG. The participants underwent a complete ophthalmologic assessment, axial length (AL) measurement, and assessments with SAP, SD-OCT, and mfVEP.
Results: POAG cases were aged 49.70 ± 14.16 years (mean ± SD) and most were females (n = 24, 60%). For eyes of patients with POAG, the mfVEP upper-ring signal-to-noise ratio (SNR) showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.33; P = 0.038), and a significant positive correlation with the superior hemifield of the visual field (VF) and the inferior-quadrant retinal nerve fiber layer (RNFL) thickness (r = + 0.34; P = 0.030; r = + 0.51; P < 0.001, respectively). Similarly, the mfVEP lower-ring SNR showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.36; P = 0.024) and a significant positive correlation with the inferior hemifield of the VF and superior quadrant RNFL thickness (r = + 0.55; P < 0.001 and r = + 0.70; P < 0.001, respectively).
Conclusions: mfVEP is a promising tool for objective assessment of the VF in patients with POAG, as it is positively correlated with the VF and OCT RNFL thickness. Future longitudinal studies with a larger sample size and a specific glaucoma subtype, along with multiple follow-up evaluations, are warranted to confirm our preliminary results
Demographic correlations for 100 most-cited authors in ophthalmic research; a bibliometric study
Get PDFBackground: To analyze the academic characteristics, career trajectory, scholarly publications, and demographic background of the 100 most-cited authors in ophthalmic literature.
Methods: In this observational cross-sectional study, a database containing every ophthalmology journal article from 1967 to 2018 was built using Scopus journal article information. The 100 authors with the most citations were identified, along with a control group of authors with at least five publications. Information about each author, such as gender, institution, and educational degrees were found from online web searches. Intra- and inter-group analyses were performed to identify correlations that may lead to having a high level of impact in ophthalmology literature.
Results: Of the 100 most-cited ophthalmologists, 56 practice in the United States (US) and only 12 are female. In an odds ratio (OR) analysis, highly-cited researchers more often lived in the US (OR, 2.97; P < 0.001), were male (OR, 2.4; P = 0.02), and graduated from an elite medical school (OR, 3.89; P = 0.02) and/or residency (OR, 3.67; P = 0.02), but were not from an undergraduate institution (P = 0.75). There was no difference in citation numbers between different ophthalmology subspecialties (P = 0.22) or advanced degrees (PhD, MPH in addition to MD). Women among the top-100-cited authors were more likely to author high impact journal articles (P < 0.05).
Conclusions: Among highly-cited ophthalmologists, practicing in the US and attending a top medical school or residency program may provide training for a successful research career in ophthalmology. Additionally, top female ophthalmologists participate in more influential research
Refractive amblyopia among children aged 4–12 years in a hospital-based setting in Gaza Strip, Palestine
Get PDFBackground: Refractive amblyopia is the most common cause of amblyopia in the Gaza Strip. However, the pattern of this condition has not yet been studied in this region. This study aimed to determine the pattern of refractive amblyopia in Gazan children aged 4–12 years.
Methods: This was a hospital-based cross-sectional study using a purposive sampling method. Children aged 4–12 years who attended the Children’s Unit at Gaza Ophthalmic Hospital, Gaza Strip, Palestine from September 2019 to July 2020, were examined. A comprehensive eye test was conducted for all participants. Those who failed the eye examinations and were diagnosed with refractive amblyopia were included in the study. Demographic data and amblyopic refractive error patterns were analyzed accordingly.
Results: Of the 107 children, 72.9% were newly diagnosed with refractive amblyopia. The mean ± standard deviation (SD) of age of the children who participated was 7.85 ± 1.55 years. Approximately two-thirds of the patients were female (57.9%). Unilateral amblyopia was predominant in 60.7% of the cases. Moderate amblyopia was common (81.9%). A total of 149 amblyopic eyes were examined in total, with a mean ± SD (range) of best-corrected distance visual acuity and spherical equivalent of 0.45 ± 0.19 (0.2 to 1.3) logarithm of the minimum angle of resolution and + 0.76 ± 4.51 diopters (- 10.25 to + 11.50). Astigmatism was the most common amblyogenic factor (53.7%) among children with amblyopia.
Conclusions: The frequency of refractive amblyopia was 72.9%, and meridional amblyopia accounted for the highest percentage. Girls were more commonly affected than boys. The majority were in the 7-year-old age group. Most cases were unilateral with moderate refractive amblyopia. Our study yields insights into the patterns of refractive amblyopia among children in the Gaza Strip
Cataract prevalence following a nationwide policy to shorten wait time for cataract surgery
Get PDFBackground: Cataract is an age-related eye disease. Visual impairment from cataract can be restored by cataract surgery. In 2004 the Canadian federal government invested in a multibillion dollar wait time strategy to shorten the wait time for cataract surgery, a government-insured health service in all Canadian jurisdictions. We assessed if this nationwide policy reduced the number of Canadians waiting for cataract surgery as more individuals with cataract were free of cataract following the rapidly conducted surgery.
Methods: In this cross-sectional study we analyzed data from randomly selected individuals aged greater than or equal to 45 years responding to the Canadian Community Health Survey (CCHS) in 2000/2001, 2003, 2005, and the CCHS Healthy Aging in 2008/2009. Information on cataract was obtained from self-reported questionnaire. The age- and sex-standardized prevalence of cataract was calculated for comparisons.
Results: Cataract was reported by 0.93 million Canadians in 2000/2001, 0.99 million in 2003, 1.10 million in 2005, and 1.34 million in 2008/2009. This corresponds to an age- and sex-standardized prevalence of 8.9% in 2000/2001, 9.0% in 2003, 9.5% in 2005, and 10.2% (P <0.05) in 2008/2009. The increase in age- and sex-standardized prevalence was greater in individuals without secondary school graduation than those with secondary school graduation or higher (4.3% versus 1.3%, P < 0.05) and was seen in all Canadian provinces. The largest increase was documented in a province (Saskatchewan, from 9.8% in 2000/2001 to 12.6% in 2008/2009, P < 0.05) with the longest median wait times for cataract surgery (118 days in 2008) and the lowest number of ophthalmologists per 100,000 population (1.96 versus 3.35 national average).
Conclusions: The age- and sex-standardized prevalence of cataract increased 4-5 years after the multibillion-dollar wait time strategy was launched in 2004. A lower threshold to diagnose cataract may be one potential reason for this finding. Further research is needed to understand the true reasons for the increase