Research Articles (Ophthalmology)
Permanent URI for this collection
Browse
Browsing Research Articles (Ophthalmology) by Title
Now showing 1 - 20 of 22
Results Per Page
Sort Options
- ItemAbnormal serum lipoprotein levels as a risk factor for the development of human lenticular opacities(Clinics Cardiv Publishing, 2003-04) Meyer, D.; Parkin, D.; Maritz, F. J.; Liebenberg, P. H.Aim: To determine whether an association exists between the different plasma lipoprotein constituents and the prevalence of lenticular opacities in dyslipidaemic subjects. Methods: Adult patients (n = 115) of both genders were included if their fasting total serum cholesterol concentrations exceeded the 95th percentile of normal or their serum low-density lipoprotein (LDL) : high-density lipoprotein (HDL) ratios exceeded 5. Patients were excluded if they suffered from any condition known to cause, or predispose them to, elevated lipoprotein levels or lenticular opacification. Lenticular changes were assessed by means of a slit-lamp through the fully dilated pupil. Results: An extremely strong association (p < 0.0001) was found to exist between HDL cholesterol levels and the development of lens opacities. Below an HDL-C level of 1.5 mmol/l subjects had a seven-fold higher calculated probability of falling in the lens opacity subgroup than those with HDL-C levels above 1.5 mmol/l [odds ratio = 7.33 (95% CI = 2.06–26.10; p = 0.001)]. An equally strong association was found between high (>5) LDL:HDL ratios and the development of lens opacities (p < 0.0003). The risk of falling into the cataract subgroup if the individual’s LDL:HDL ratio exceeded 5 was 2.35 (95% CI = 1.09–5.04; p = 0.014). Conclusions: This study strongly suggests that an association exists between low levels of HDL cholesterol and high LDL:HDL ratios on one hand and the development of adult lens opacification on the other.
- ItemAnti-allergic ophthalmic drugs in general practice : which, why and when?(Medpharm Publications, 2013) Mohamed, N.; Smit, D. P.Ocular allergies present in many different guises. They may vary from self-limiting episodes of acute allergic conjunctivitis, to potentially sight-threatening chronic conditions, such as vernal keratoconjunctivitis. This article provides a brief description of the different ocular allergic conditions to aid accurate diagnosis. It also focuses on the different types of anti-allergic ophthalmic preparations and how to employ them in a logical, stepwise management strategy to obtain optimal results, while minimising exposure to potent drugs with potentially serious side-effects.
- ItemAnti-infective ophthalmic preparations in general practice(Medpharm Publications, 2012) Smit, DerrickOcular infections may be bacterial, viral, fungal or parasitic in aetiology. Pharmacological preparations are available to treat infections that are caused by these groups of organisms. The majority of these preparations are intended for topical administration, although some systemically administered agents may be needed to treat or prevent specific ocular infections. This article discusses the different anti-infective options that are available to general practitioners to treat infections caused by each aetiological group. It also discusses the role that is played by povidone-iodine and antibiotic-steroid combinations to manage eye infections. A summary of all these drugs is provided in table form for easy reference.
- ItemAstute and safe use of topical ocular corticosteroids in general practice : practical guidelines(Health and Medical Publishing Group (HMPG), 2013-04) Janse van Rensburg, E.; Meyer, D.Corticosteroids are the most effective way to treat ocular inflammation. They relieve symptoms rapidly and often prevent permanent damage. These medications, however, must be used with caution, as use of steroid-containing topical drops can lead to serious side-effects. In situations where resources are limited it is often difficult to decide if steroids can be given safely. The purpose of this article is to briefly review the most important features of topical steroids and provide a practical and safe guideline for their use in general practice
- ItemBiomarkers as a predictor for diabetic retinopathy risk and management : a review(AOSIS, 2018) Phillips, Kevin C.; Clarke-Farr, Peter C.; Matsha, Tandi E.; Meyer, DavidBackground: The systemic and ocular manifestations of diabetes are an increasing burden on both private and public healthcare systems. The ability to accurately predict patient susceptibility and prognostic implications of the disease is essential to its optimal management and planning. Aim: The purpose of this paper was to review alternative biomarkers to those currently in use regarding the diagnosis and prognosis of diabetes and the ocular effects of the disease. Current biomarkers include Fasting Plasma Glucose (FPG), Oral Glucose Tolerance Test (OGTT) and Glycolated Haemoglobin (HbA1c). Methods: The research strategy comprised of a comprehensive literature review of articles from Mendeley, Cochrane and Elsevier with additional input from experts in the field serving as co-authors. Results: The review found that there are alternative biomarkers to those currently utilised. These include adiponectin, apolipoprotein B, C-reactive protein and ferritin. Fructosamine, while useful where whole blood is available, is unreliable as a diagnostic biomarker resulting in a 10% variation coefficient. Post-prandial glucose (PPG) measurement most closely predicted HbA1c. Conclusion: With prediction of risk for diabetes in individuals, a value combination, expressed as either a numerical score or a percentage, consisting of adiponectin, apolipoprotein B, C-reactive protein and ferritin, almost doubled the relative risk of contracting the disease. Eye care practitioners need to question diabetic patients about their FPG and HbA1c levels and encourage them to have the relevant tests regularly, including PPG. The importance of biomarkers should be emphasised and used as an educational tool to facilitate better diabetes management and treatment adherence.
- ItemCortical lens opacities in the young patient - an indication for a lipogram?(Health & Medical Publishing Group, 2001) Meyer, D.; Maritz, F. J.; Liebenberg, P. H.; Parkin, D. P.; Burgess, L. J.Aim. To determine the characteristics and prevalence of lenticular opacification in patients with underlying dyslipidaemia. Methods. Eighty patients of both genders and all ages (18 - 90 years) were enrolled in the trial if they met the inclusion criteria for dyslipidaemia. Patients were included if their fasting serum cholesterol and triglyceride concentrations were > 5.2 mmol/1 and > 2.3 mmol/1, respectively, when measured on three separate occasions over a 1-month period. Patients were excluded if they suffered from any condition known to cause or predispose them to elevated lipid levels or lenticular opacification. Lenticular changes were assessed by means of a slit-lamp through the fully dilated pupil and other physical signs were documented subsequent to thorough physical evaluation. Results. In addition to the classic clinic signs of dyslipidaemia, 31% of patients had cortical lens opacities. Cortical opacities were twice as prevalent as Achilles tendon thickening (16.3%) in our study, the second most prevalent sign of elevated lipid levels. In the subgroup of patients aged under 50 years, 55% had lenticular opacities, predominantly cortical (80%). Conclusions. Cortical lens opacification was the most prevalent sign of dyslipidaemia and it occurred at a relatively young age in our trial population in those patients who were affected. Cortical lenticular opacification should be regarded as an indication for blood lipid profile evaluation.
- ItemDealing with dry eye disease in general practice(Medpharm Publications, 2012) Smit, DerrickDry eye disease (DED) is a very common condition with significant morbitity. It is under-diagnosed by healthcare practitioners, since the presenting symptoms are often non-specific or misleading, and clinical signs may be subtle, or absent. To help overcome this problem, validated symptom questionnaires have been developed to aid the diagnosis, and grading of severity, of DED. Recent advances in the understanding of the multifactorial aetiology of this condition have also permitted the development of modalities aimed at treating specific underlying causes, rather than merely alleviating symptoms. An awareness of the causes and risk factors involved in this disease will assist the family practitioner in recommending lifestyle and dietary changes that, on their own, may provide sufferers with considerable symptomatic relief. A better understanding of the pathophysiology will, in turn, allow the family practitioner to make informed choices when prescribing initial treatment, and also guide the practitioner to know when to refer a patient for specialist management.
- ItemEfficacy of cryotherapy in retinoblastoma(Health & Medical Publishing Group, 1976) Molteno A. C. B.Five cases of retinoblastoma treated by freezing are reported. From these cases it appears that a single freeze thaw cycle will destroy all tumor and that with suitable instruments it is possible to destroy tumors involving up to 30% of the volume of the globe without causing blindness.
- ItemEyelid problems in general practice(Medpharm Publications, 2012) Smit, Derrick P.General practitioners are often confronted with complaints regarding the eyelids. The author presents a number of clinical cases that illustrate common eyelid problems, and provides a discussion of each case to highlight the important features of the condition. Appropriate treatment for each condition is also covered. Many eyelid conditions are amenable to treatment from general practitioners, but those conditions requiring specialist management need to be identified, and referred appropriately.
- ItemFundus auto fluorescence and spectral domain ocular coherence tomography in the early detection of chloroquine retinopathy(AOSIS Publishing, 2015-08-21) Goodman, Megan B.; Ziskind, AriPurpose: To determine the sensitivity of spectral domain ocular coherence tomography (SD-OCT) and fundus auto fluorescence (FAF) images as a screening test to detect early changes in the retina prior to the onset of chloroquine retinopathy. Method: The study was conducted using patients taking chloroquine (CQ), referred by the Rheumatology Department to the Ophthalmology Department at Tygerberg Academic Hospital. Group A consisted of 59 patients on CQ for less than 5 years, and Group B consisted of 53 patients on CQ for more than 5 years. A 200 × 200 macula thickness map, 5-line raster SD-OCT on a Carl Zeiss Meditec Cirrus HD-OCT and FAF images on a Carl Zeiss Meditec Visucam 500 were recorded for 223 eyes. Images were reviewed independently, and then those of Groups A and B compared. Results: There were no statistically significant differences between Groups A and B. The criteria included the internal limiting membrane and the retinal pigment epithelium (ILM-RPE) thickness, interdigitation zone integrity (p = 0.891, df = 1, χ² = 0.1876), ellipsoid zone integrity (p = 0.095, df = 2, χ² = 4.699) and FAF image irregularities (p = 0.479, df = 1, χ² = 4995978). Conclusion: The inclusion of SD-OCT and FAF as objective tests into the prescribed screening guidelines does not appear to simplify the detection of subclinical injury in patients on chloroquine treatment.
- ItemIntra-ocular concentration-time relationships of subconjunctivally administered gentamicin(Health & Medical Publishing Group, 1991) Van Rooyen, M. M. B.; Coetzee, J. F.; Du Toit, D. F.; Van Jaarsveld, P. P.Eighty-nine patients scheduled for cataract removal or lens implantation were divided randomly into three groups. Each received 5, 10 or 20 mg gentamicin subconjunctivally at times varying between 0,2 and 19 hours pre-operatively. At surgery a sample of aqueous humour was obtained and analysed for gentamicin concentration. The data for each group were subjected to non-linear regression analysis to fit an open one-compartment pharmacokinetic model with first-order kinetics. A statistically acceptable fit was obtained. The average values of the pharmacokinetic parameters obtained from the single doses were used to simulate multiple-dose kinetics. The average target intra-ocular gentamicin concentrations and dosage interval were specified in the computer program, which subsequently allowed calculation of the dose required. This allowed the construction of a simple linear nomogram that can be used to read off the dose needed for handling specific clinical situations.
- ItemThe intraocular pressure-lowering properties of intravenous paracetamol(Dove Medical Press, 2016) Van Den Heever, Henning; Meyer, DavidAim: The aim of this paper was to investigate the intraocular pressure (IOP)-changing properties of a single standard dose of intravenous (IV) paracetamol and compare it to that of topical timolol, oral acetazolamide, and no treatment. Methods: A prospective, randomized, investigator-blind, parallel-group study was conducted in 73 eyes of 52 subjects. Subjects received a single dose of IV paracetamol (1 g), oral acetazolamide (250 mg), topical timolol (0.5%, one drop), or no treatment. Baseline IOP was measured, and the measurement was repeated at 1, 2, 4, and 6 hours after treatment. Results: Paracetamol reduced IOP from baseline by -10.8% (95% confidence interval [CI]: -4.9% to -16.8%, P=0.146) at 1 hour, -13.3% (95% CI: -8.3% to -18.4%, P=0.045) at 2 hours, -11.8% (95% CI: -5.5% to -18.4%, P=1.000) at 4 hours, and -23.9% (95% CI: -17.8% to -30.1%, P=0.006) at 6 hours after treatment. In the no-treatment group, the change was -2.9% (95% CI: +1.0% to -6.7%, P= referent) at 1 hour, -2.1% (95% CI: +2.9% to -7.2%, P= referent) at 2 hours, -7.6% (95% CI: -3.9% to -11.2%, P= referent) at 4 hours, and -6.9% (95% CI: -3.6% to -10.2%, P= referent) at 6 hours. Acetazolamide reduced IOP by -18.8% (95% CI: -12.7% to -24.8%, P=0.000) at 1 hour, -26.2% (95% CI: -18.2% to -34.2%, P=0.001) at 2 hours, -24.6% (95% CI: -16.9% to -32.3%, P=0.000) after 4 hours, and -26.9% (95% CI: -19.6% to -34.3%, P=0.000) 6 hours after treatment. Timolol reduced IOP by -31.2% (95% CI: -26.7% to -35.7%, P=0.000) at 1 hour, -27.7% (95% CI: -20.7% to -34.8%, P=0.000) at 2 hours, -28.7% (95% CI: -21.1% to -36.2%, P=0.000) at 4 hours, and -21.3% (95% CI: -13.4% to -30.0%, P=0.030) at 6 hours after treatment. The average change in IOP for the no-treatment group was -4.8% (95% CI: -2.6% to -6.9%, P= referent). It was -15.7% (95% CI: -9.3% to -22.1%, P=0.021) for paracetamol, -23.1% (95% CI: -16.4% to -29.8%, P=0.000) for acetazolamide, and -25.3% for the timolol group (95% CI: -19.4% to -31.2%, P=0.000). The maximal change in IOP for the no-treatment group was -9.2% (95% CI: -3.2% to -15.3%, P= referent). It was -25.9% (95% CI: -16.6% to -35.2%, P=0.009) for paracetamol, -33.8% (95% CI: -25.5% to -42.1%, P=0.000) for acetazolamide, and -36.8% (95% CI: -31.0% to -42.5%, P=0.000) for the timolol group. Conclusion: Intravenously administered paracetamol shows IOP-lowering properties over the first 6 hours after administration. Clinicians performing IOP measurements in patients who have received IV paracetamol in the preceding 6 hours should interpret these measurements with caution. Further studies are needed to investigate the IOP-changing properties of paracetamol.
- ItemManagement of chemical ocular injuries – what every GP should know(Health and Medical Publishing Group (HMPG), 2013-04) Meyer, D.; Jansen van Rensburg, J.
- ItemOutpatient treatment of retinal detachment(Health & Medical Publishing Group, 1989-01) Van Rooyen, M. M. B.; Van Biljon, G.; Du Toit, A. M.Outpatient treatment of retinal detachment is a new concept. The first 20 cases treated in the Department of Ophthalmology at Tygerberg Hospital are discussed. After an inert gas has been injected into the vitreous cavity the patient is allowed to go home, where he must remain in the therapeutic position. When the patient returns the next day the retina will usually be reattached around the breaks, and laser photocoagulation or cryopexy is performed. The succes rate is high, and this procedure should be considered in all cases in which it is indicated.
- ItemPaintball ocular injuries(Health & Medical Publishing Group, 1999) Kruger, L. P.; Acton, J. K.Introduction. Six cases of ocular injury following paintball injuries sustained during war games are described. A CO2-powered rifle shoots a 14 mm plastic-coated paintball at participants. The muzzle velocity of the gun is 250 ft/sec (76 m/sec). Locally manufactured paintballs are harder than the more expensive imported varieties and may account for the severity of our reported injuries. Method. Six patients presented to a retinal specialist with various ocular injuries, predominantly of the posterior pole. Results. All patients were young males. There were no cases of ocular penetration. A variety of retinal pathologies was noted, with three cases requiring surgery; however this did not significantly improve the visual outcome. Conclusions. These cases highlight the severe ocular injuries that may occur from paintball injuries. Recommendations to avoid ocular injury are made.
- ItemPolymerase chain reaction to search for Herpes viruses in uveitic and healthy eyes : a South African perspective(Makerere University, Faculty of Medicine, 2015) Laaks, Debbie; Smit, Derrick Peter; Harvey, JustinObjective: To analyse aqueous polymerase chain reaction (PCR) results in patients diagnosed with undifferentiated uveitis and determine prevalence of herpesviridae in non-uveitic patients undergoing routine cataract extraction. Design: Retrospective comparative case series and prospective cross-sectional study. Subjects: 72 patients with idiopathic uveitis and 57 surgical patients. Methods: Diagnostic aqueous paracentesis with PCR testing for 6 herpes viridae in uveitic patients. Anterior chamber paracentesis immediately pre-operative in the prospective arm, with PCR testing. Results: In the retrospective review we had a 47.2% positive PCR yield. Data analysis revealed a statistically significant correlation between a positive yield and being HIV+ (p=0.018); between an EBV+ yield and being HIV+ (p= 0.026) and a CMV+ result and being HIV+ (p=0.032). Posterior uveitis (p=0.014) and symptoms <30 days (p= 0.0014) had a statistically significant yield. In the prospective arm of the study: all 57 patients were HIV- and all aqueous samples were negative for the 6 herpesviridae. Conclusion: We recommend PCR testing for Herpesviridae as a safe second line test for patients with undifferentiated uveitis. We were unable to establish prevalence and suggest that the idea of a commensal herpes virus is unlikely if the blood-ocular barrier is intact
- ItemRetinopathy in diabetic patients evaluated at a primary care clinic in Cape Town(Health & Medical Publishing Group, 2007-10) Read, Olivia; Cook, ColinDiabetic retinopathy is the fifth leading cause of global blindness, affecting an estimated 1.8 billion people and responsible for 4.8% of blindness.1 In South Africa, it is the third leading cause of blindness after cataract and glaucoma, and is responsible for 5% of blindness (0.04% of the total population). Cataract and refractive error are prioritised for the first phase of Vision 2020 in South Africa, while strategies to deal with diabetic retinopathy are recommended as a priority for the second phase.2 These strategies will include provision of adequate screening and argon laser treatment. The prevalence of diabetes differs in different population groups in South Africa. Among black and coloured South Africans, diabetes has risen from 3% to 12% over the past 10 years. Overall, the prevalence is conservatively estimated to be 3 - 5% (30 000 - 50 000 per million population).2 The prevalence of retinopathy in people with diabetes is estimated to be 20% (6 000 - 10 000 per million population), and the prevalence of blindness among these is estimated to be 5% (300 - 500 blind per million population).2 The objective of this study was to evaluate the retinopathy status of patients with diabetes seen at a primary care clinic in Cape Town and to assess the adequacy of the current diabetic screening programmes.
- ItemScreening for retinitis in children with probable systemic cytomegalovirus infection at Tygerberg Hospital, Cape Town, South Africa(Health and Medical Publishing Group, 2017) Engelbrecht, J. F.; Freeman, N.; Rautenbach, R. M.Background. The incidence of immunocompromised children with probable systemic cytomegalovirus (CMV) infection is increasing. Currently, there is no protocol for screening children for CMV retinitis in South Africa. Screening for CMV retinitis may prevent permanent visual impairment. Objectives. To determine the prevalence of retinitis in children with probable systemic CMV infection. To assess the value of clinical and laboratory data in identifying risk factors for the development of CMV retinitis in children. Methods. A retrospective, cross-sectional study design was used. All children (≤12 years) with probable systemic CMV infection who underwent ophthalmic screening over a 5-year period, were included. Presumed CMV retinitis was diagnosed by dilated fundoscopy. All cases were evaluated to identify possible risk factors for the development of CMV retinitis. Results. A total of 164 children were screened. Presumed CMV retinitis was diagnosed in 4.9% of participants. Causes of immunosuppression were HIV infection (n=7) and chemotherapy (n=1). HIV infection showed a definite trend towards association with the development of CMV retinitis in our study population (p=0.064). Conclusion.The prevalence of CMV retinitis was 4.9% in our sample. Other than HIV, we were not able to identify additional risk factors for CMV retinitis. Our results show that CD4 levels are possibly not a reliable indicator to predict CMV retinitis.
- ItemSerum lipid parameters and the prevalence of corneal arcus in a dyslipidaemic patient population(Clinics Cardiv Publishing, 2004-08) Meyer, D.; Liebenberg, P. H.; Maritz, F. J.Aim: To determine whether an association exists between plasma lipoprotein constituents and the prevalence of corneal arcus in dyslipidaemic patients. Methods: Adult patients (n = 115) were included if their fasting total serum cholesterol concentrations exceeded the 95th percentile or their serum low-density lipoprotein (LDL) : high density lipoprotein (HDL) ratios exceeded 5. Slit-lamp assessment of the corneas was performed. Results: The study group divided into a subgroup with arcus 37% (43) and a subgroup without arcus 63% (72). Total serum cholesterol and triglyceride levels were not associated with corneal arcus. A significant difference was found (p < 0.05) between the mean levels of LDL cholesterol (LDL-C) in the group without arcus (5.61 ± 1.74 mmol/l) and the group with arcus (5.96 ±1.71 mmol/l). The mean serum HDL-cholesterol (HDL-C) in the group with corneal arcus was 1.04 ± 0.30 mmol/l as opposed to 1.31 ± 0.38 mmol/l in the group without arcus (p < 0.005 for difference). The mean LDL-C : HDL-C ratio in the group without arcus was 4.28 (SD: 1.99), and 5.73 (SD: 2.09) in the group with a corneal arcus (p < 0.05). Conclusions: Low HDL-C levels, high LDL-C levels and LDL-C : HDL-C ratios > 5 have been implicated as risk factors of numerous circulatory diseases. The observations in this study suggest that the presence of corneal arcus in the dyslipidaemic patient correlates strongly with these same risk indicators.
- ItemSmall-gauge pars plana vitrectomy for the management of symptomatic posterior vitreous detachment after phacoemulsification and multifocal intraocular lens implantation : a pilot study from the Pan-American Collaborative Retina Study Group(Hindawi, 2015-08) Navarro, Rodrigo M.; Machado, Leonardo M.; Maia Jr., Ossires; Wu, Lihteh; Farah, Michel E.; Magalhaes Jr., Octaviano; Arevalo, J. Fernando; Maia, MauricioPurpose. To determine the efficacy of 23-gauge pars plana vitrectomy (PPV) for symptomatic posterior vitreous detachment (PVD) on visual acuity (VA) and quality after multifocal intraocular lenses (IOLs). Methods. In this prospective case series, patients who developed symptomatic PVD and were not satisfied with visual quality due to floaters and halos after multifocal IOL implantation underwent PPV. Examinations included LogMAR uncorrected visual acuity (UCVA), intraocular pressure, biomicroscopy, and indirect ophthalmoscopy at baseline and 1, 7, 30, and 180 days postoperatively. Ultrasonography and aberrometry were performed. The Visual Functioning Questionnaire 25 (VFQ-25) was administered preoperatively and at 30 days postoperatively. Both the postoperative UCVA and questionnaire results were compared to preoperative findings using the Wilcoxon test. Results. Sixteen eyes of 8 patients were included. VA significantly improved from 0.17 to 0.09 postoperatively (𝑃 = 0.017). All patients reported improvement of halos, glare, and floaters. VFQ-25 scores significantly improved in general vision (𝑃 = 0.023), near activities (𝑃 = 0.043), distance activities (𝑃 = 0.041), mental health (𝑃 = 0.011), role difficulties (𝑃 = 0.042), and driving (𝑃 = 0.016). Conclusion. PPV may increase UCVA and quality of vision in patients with bilateralmultifocal IOLs and symptomatic PVD. Larger studies are advised