Ophthalmology

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Abnormal 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.
Anti-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.
Anti-infective ophthalmic preparations in general practice
(Medpharm Publications, 2012) Smit, Derrick
Ocular 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.
Astute 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
Biomarker concentrations in serum and urine of patients with Ocular Tuberculosis – a prospective descriptive study.
(Stellenbosch : Stellenbosch University, 2022-03) Van der Colff, Frederich James; Smit, Derrick; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Ophthalmology
ENGLISH ABSTRACT: Purpose: To describe biomarker concentrations in serum and urine of South African patients with ocular tuberculosis (OTB). Methods: A prospective study to compare 29 urine and serum biomarkers in 14 OTB patients at a tertiary eye clinic. Results: Median age of participants (7 male and 7 female) was 38.5 years (range 25‐73). Most biomarker concentrations were significantly higher in serum than in urine (p < 0.01). Only two (IL‐1RA and IL‐2) showed higher concentrations in urine than serum (p < 0.01). Three biomarkers (sIL‐2Ra, sTNFRI and IFNγ) showed no difference in concentration between urine and serum (p > 0.05). Conclusions: Most biomarkers tested showed significant differences in concentration between serum and urine and therefore these 2 biofluids cannot be used interchangeably when studying biomarker profiles. One notable exception is IFNγ, as its concentration did not differ between serum and urine.
Biomarkers as a predictor for diabetic retinopathy risk and management : a review
(AOSIS, 2018) Phillips, Kevin C.; Clarke-Farr, Peter C.; Matsha, Tandi E.; Meyer, David
Background: 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.
Clinical and laboratory characteristics of ocular syphilis and neurosyphilis among individuals with and without HIV infection
(Stellenbosch : Stellenbosch University, 2022) Mathew, Dony Korah; Smit, Derrick; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Ophthalmology.
ENGLISH ABSTRACT: BACKGROUND/AIMS: In the era of increasing incidence of syphilis globally, ocular syphilis is re-emerging as an important cause of uveitis. The aim of this study was to determine the clinical and laboratory characteristics of ocular- and neurosyphilis among individuals with and without HIV infection. METHODS: Retrospective analysis of patients diagnosed with ocular syphilis presenting to Tygerberg Hospital, South Africa, over a 5-year period ending December 2018. RESULTS: Two-hundred-and-fifteen eyes of 146 patients were included. HIV co-infection was present in 52.1% of the patients, with 23.7% of these patients being newly diagnosed on presentation. The median age was 36.5 + 9.8 years. Bilateral involvement occurred in 47.3%; with 68.1% of these patients being HIV positive. The most frequent form of intraocular inflammation was posterior uveitis (40.9%), followed by panuveitis (38.1%); both of which were more predominant in HIV-positive eyes. Seventy-four percent of all eyes had a visual acuity < 20/50 and 40% < 20/200 at presentation. A lumbar puncture was performed in 113 patients (77.4%). Sixteen patients had confirmed neurosyphilis and 27 probable neurosyphilis according to the UpToDate algorithms. CONCLUSION: This study included the largest number of ocular syphilis cases with the largest proportion of HIV infection to date. Forty-three of 146 patients (29.5%) had neurosyphilis. HIV status must be determined in all patients with ocular syphilis since almost ¼ of patients were newly diagnosed with HIV infection by doing so.
Congenital and genetic disruptions of human ocular motility and alignment – phenotypic / genotypic bi-directional algorithm
(Stellenbosch : Stellenbosch University, 2019-04) Oystreck, Darren T; Meyer, David; Stellenbosch University. Facult of Medicine and Health Sciences. Dept. of Surgical Sciences: Ophthalmology
ENGLISH ABSTRACT: Our understanding of congenital and genetic disruption to human ocular motility and alignment has expanded significantly over the past 15 years due in large part to advances in genetics. This has permitted identification of many underlying genetic causes in several conditions and provided new insight into the development and function of the oculomotor system. However, this information has also disturbed current classification systems based almost exclusively on ocular motility characteristics resulting in a knowledge gap between clinicians and researchers. As part of a team of researchers from several institutions a series of studies were conducted to better elucidate the clinical and genetic features in a large heterogeneous group of subjects with known or suspected congenital or genetic disorders affecting ocular motility and alignment. This dissertation is the outcome of this work. It also provided an opportunity to assess the value of the orthoptic evaluation by critically evaluating ocular motility and alignment patterns in this population. The main objective was to identify key patterns that can be used to predict underlying genotypes. This could provide a more rapid, cost effective approach to these disorders and better define the role for the general ophthalmologist in the investigation. This work spans over a decade and resulted in 47 publications that provide key pieces to the expanding body of knowledge in this field. Several publications served as reviews for knowledge translation for the ophthalmologist and one focuses on summarizing the orthoptic evaluation. In total 845 enrolled subjects received orthoptic evaluations. This included 40 different diagnoses and 25 different genes with mutations identified. The orthoptic information in these subjects formulated part of all research team publications. Despite only scratching the surface of the entire domain of genetic ocular motility and alignment disorders, this is likely is the largest and broadest collection of diagnoses in one report. A new classification scheme is proposed, one that is based on the underlying pathomechanisms accounting for disruption to ocular motility and alignment. A simplified clinical approach has been developed for the general ophthalmologist to utilize key orthoptic assessments as aids in appropriately classifying encountered subjects. This is important as each diagnostic category of conditions generally requires different investigations and management. This research also identified significant phenotypic overlap in genetically distinct disorders and phenotypic variability in the same genetic disorder. Therefore it is concluded that orthoptic features in isolation cannot be used to reliability predict the underlying genotype. The addition of information from other medical specialties improves this prediction. However, due to the currently small number of genotyped individuals in many of these rare disorders, more research is required before definitive genotype-phenotype spectrums can be identified. It is also emphasizes the need for standardization of the orthoptic assessment and reporting of the findings to ensure that similarities and differences be identified accurately.
Cortical 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.
A critical appraisal of the etiology of adult human lenticular opacification and an investigation into the role of metabolic factors in its pathogenesis
(Stellenbosch : Stellenbosch University, 2001-12) Meyer, David; Parkin, D. P.; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Surgical Sciences. Ophthalmology.
ENGLISH ABSTRACT: The eye is that biological instrument which conveys the light of the external world into the inner world of the mind, wherein we receive the miraculous gift of vision. So precious is this gift, that Science must search for ways to keep this portal clear for the flow of light. Indeed, Science is called upon to “make war upon the bloody tyrant, Time.” (Shakespeare W. Sonnet No. 16). For, in the course of ageing, the lens grows cloudy and cataractous. In this battle between Science and Time, we are fortunate to live in an era in which Science is uncovering the molecular basis for the various obstacles to vision. The question arises, whether or not, the ruinous hand of time can be stayed. Due to unrelenting, progressive lens opacification, most of the elderly are destined to be subjected to loss of vision and with passage of time, even blindness. Globally the cataract surgery rate is inadequate to keep pace with the ever growing demand on financial and human resources created by the cataract problem. An immense challenge therefore is directed to primary eye care: “Can cataract be prevented or can its onset at least be postponed?” This laudable ultimate aim can only be achieved once the etiology of cataractogenesis is well understood. This dissertation seeks to examine two previously unrecognized etiological aspects that, if correctly understood and managed, have the potential to achieve preventive ophthalmological goals that may indeed help to stay the ‘ruinous hand of time’. The first aspect deals with the role of lipids and was examined using a study group of dyslipidemic subjects. The first part of the study concluded that dyslipidemic patients develop cortical lens opacities more frequently and at an earlier age than the normal population, and that cortical lens opacities should be regarded as one of the most reliable clinical signs of dyslipidemia. Furthermore, an extremely strong correlation was found to exist between low HDL Cholesterol levels and the development of opacities. Below a HDL-Cholesterol level of 1,5mmol/l, subjects had more than seven-fold higher risk of falling in the lens opacity subgroup than those with HDLCholesterol levels above 1,5mmol/l. An equally strong correlation was demonstrated between high (>5) LDLHDL ratios and the development of lens opacities. Subjects with a LDL:HDL-C ratio below 5 possessed a 2.35 times greater risk of having lenticular opacities than the group with a LDL:HDL-C ratio greater than 5. The prevention or retardation of dyslipidemia associated lens opacities is therefore possible, provided patients with a genetic predisposition are detected early and their blood lipids managed adequately. The second aspect deals with the relationship between age related cataracts and the acetylation status of the individual. This study compellingly submits that the slow acetylator pheno- and genotype may be regarded as a genetic indicator of risk for age related cataract. The ability accurately to classify a patient genotypically and phenotypically, may henceforth be useful in health counseling since, if an individual is identified as being a slow acetylator, additional preventative and precautionary measures may be taken, i.e. the prevention of UVexposure to the eye and caution with the ingestion of xenobiotics like caffeine, commercial dyes, food preservatives, and drugs. Furthermore, such a finding should be taken into account in the long term therapeutic management of glaucoma, with special regard to carbonic anhydrase inhibitors which are sulphonamide-related drugs and totally dependent on the N-acetyltransferase pathway for metabolism. These drugs may accumulate in the slow acetylator over time and exert toxic effects intra-ocularly, conceivably including cataractogenesis. The search for genetic and metabolic mechanisms that may contribute to human cataractogenesis should be pursued with great enthusiasm. This endeavour may help Science to achieve its primary objective, ablate the effects of Time and really aid in preventing cataracts in man.
CXCL13, CXCL10 and CXCL8 as indicators of ocular and neurological involvement in patients with ocular syphilis: an observational descriptive study
(Stellenbosch : Stellenbosch University, 2022) Van der Merwe, Laurie Wiid; Smit, Derrick; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Ophthalmology.
ENGLISH ABSTRACT: Aim To investigate the role of the chemokines CXCL13, CXCL10 and CXCL8 in the diagnosis of ocular‐ and neurosyphilis by examining the serum, aqueous humour (AH) and cerebrospinal fluid (CSF) of patients with ocular syphilis. Methods An observational descriptive study was performed prospectively at Tygerberg Academic Hospital in Cape Town, South Africa from 1 February 2018 till 31 January 2021 which enrolled 23 participants. Upon diagnosis of ocular syphilis, the HIV status of each patient was determined, and 3 samples (AH, serum and CSF) were collected to measure the levels of CXCL13, CXCL10 and CXCL8 in each. Results The mean concentrations of all 3 biomarkers were higher in the AH and CSF than in the serum. The mean concentrations of the 3 measured biomarkers were markedly different when comparing both AH and CSF levels to serum levels. The level of CXCL13 measured in the AH correlated well with the concentrations found in the CSF of patients with neurosyphilis. In patients with neurosyphilis, mean AH levels of CXCL13 and CXCL10 were markedly higher than in serum while mean CSF levels of CXCL10 were also markedly higher than in serum. Also, the AH/serum ratio of CXCL13 and CXCL10, as well as the CSF/serum ratio of CXCL10, was much higher in patients with neurosyphilis than without. In patients with HIV infection, mean AH CXCL13 levels were much higher than in patients without HIV infection. Conclusion The levels of CXCL13, CXCL10 and CXCL8 in the AH of patients with neurosyphilis are similar to previously reported levels in the CSF of patients with neurosyphilis and can potentially be an adjunct in the diagnosis of ocular syphilis. Patients with ocular syphilis who tested negative for neurosyphilis with conventional CSF testing showed features of neurosyphilis when analysing the CSF chemokines.
Dealing with dry eye disease in general practice
(Medpharm Publications, 2012) Smit, Derrick
Dry 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.
The efficacy and safety of diode laser cycloablation in the treatment of refractory glaucoma in a South African population
(Stellenbosch : Stellenbosch University, 2022-04) Thomas, Jason Peter; Smit, Derrick; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Ophthalmology
ENGLISH SUMMARY: The development of a safe and effective protocol for trans-scleral cyclophotocoagulation in a Southern African population presenting with refractory glaucoma to a tertiary eye care centre. prospective, non-randomised, observational study of patients attending the Eye Clinic at Tygerberg Hospital, Cape Town, South Africa between March 2018 and January 2020. 119 eyes of 105 eligible patients were treated during the study period. The mean laser power was 1766 ± 187 milliwatt per burn for a mean of 15.6 ± 2.9 burns per eye. Mean total delivered energy per eye was 55.28 ± 12.61 Joule. 64% of the patients who followed up for the entire six-month period had an intraocular pressure reduction of ≥ 30% and 42.2% of those followed up had an IOP of ≤ 22 mmHg. The pain scores reported by patients decreased significantly between pre-operatively and three months (coefficient -1.752, p<0.001) and between pre-operatively and six months (coefficient -1.498, p=0.002). There was not a statistically significant effect on the change in topical medication from pre-operatively to three months (coefficient = -0.089, p=0.186), nor from pre-operatively to six months (coefficient = -0.003, p=0.946). Oral acetazolamide use decreased from 50.4% of patients at the date of their initial cyclophotocoagulation treatment to 9.3% at three months and further to 7.8% at six months. One eye had a scleral perforation at the time of initial treatment; no further complications arose. An individualized, “pop-titrated” cyclophotocoagulation protocol is safe and effective for use in a Southern African population. Retreatment should be considered at three months if intraocular pressure is not adequately controlled.
Efficacy 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.
Eyelid 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.
Fundus auto fluorescence and spectral domain ocular coherence tomography in the early detection of chloroquine retinopathy
(AOSIS Publishing, 2015-08-21) Goodman, Megan B.; Ziskind, Ari
Purpose: 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.
Hutchinson's sign as a marker of ocular involvement in HIV-positive patients with herpes zoster ophthalmicus
(Health and Medical Publishing Group (HMPG), 2010) Van Dyk, M.; Meyer, D.
Background. A positive Hutchinson's sign indicates an increased risk of ocular involvement in herpes zoster ophthalmicus (HZO). We examined the sensitivity of Hutchinson's sign as an indicator of ocular involvement in a consecutive series of patients presenting with HZO. Methods. We conducted a descriptive observational prospective study of patients ≥18 years old presenting with HZO and consenting to pre- and post-test counselling and HIV and CD4 testing. A full ophthalmological examination focused on the extent of ocular involvement, and the presence of Hutchinson's sign was confirmed by two clinicians. Results. Thirty-three patients were enrolled; 29 were HIV positive, of whom 18 (62%) had not been diagnosed with HIV prior to enrolment. Of the 29 HIV-positive patients, 21 (72%) were Hutchinson's sign positive (HSP), all of whom had intra-ocular involvement (95% confidence interval 88 - 100%). Of the 8 HIV-positive, Hutchinson's sign-negative (HSN) patients, 4 did and 4 did not display intra-ocular involvement. Neither the mean CD4 count nor the average age in the HSP group differed significantly from the HSN group. Conclusion. We confirmed that a Hutchinson's sign- and HIVpositive patient with HZO has a very high positive predictive value for intra-ocular involvement. Neither age nor CD4 count had predictive value for ocular involvement. Young adults presenting with HZO should be suspected of having HIV, and HIV-positive patients with HZO but HSN may still have ocular involvement. All patients with HZO should be seen by an ophthalmologist.
Intra-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.
The intraocular pressure-lowering properties of intravenous paracetamol
(Dove Medical Press, 2016) Van Den Heever, Henning; Meyer, David
Aim: 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.
Long tube implants in the management of glaucoma
(Health & Medical Publishing Group, 1976) Molteno, A. C. B.; Straughan, J. L.; Ancker, E.; Molteno, A. C. B.; Straughan, J. L.; Ancker, E.
The design, surgical insertion and results of a plastic draining implant for severe glaucoma are reported. The need for pharmacological control of bleb inflammation is stressed and the favourable long term outlook for patients with such implants is discussed.

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