Showing papers in "Eye in 1997"
TL;DR: The computer system can reliably detect microaneurysms and the advantages of the computer system include objectivity, repeatability, speed and full automation.
Abstract: A fully automated digital image processing system, which provides an objective and repeatable way to quantify microaneurysms in digitised fluorescein angiograms, has been developed. The automated computer processing includes registration of same-eye retinal images for serial studies, cutting of regions-of-interest centred on the fovea, the detection of microaneurysms and the comparison of serial images for microaneurysm turnover. The microaneurysm detector was trained against a database of 68 images of patients with diabetes containing 394 true microaneurysms, as identified by an ophthalmologist. The microaneurysm detector achieved 82% sensitivity with 2.0 false-positives per image. An independent test set, comprising 20 images containing 297 true microaneurysms, was used to compare the microaneurysm detector with clinicians. The microaneurysm detector achieved a sensitivity of 82% for 5.7 false-positives per image, whereas the clinician receiver-operator-characteristic (ROC) curve gives 3.2 false-positives per image at a sensitivity of 82%. It is concluded that the computer system can reliably detect microaneurysms. The advantages of the computer system include objectivity, repeatability, speed and full automation.
183 citations
TL;DR: This review presents the concepts that underpin the theories of corneal transparency, particularly in the years since the advent of the electron microscope, which has brought about a much greater understanding ofCorneal ultrastructure.
Abstract: An understanding of the physical basis of corneal transparency has been a subject of interest amongst physicists, basic scientists and ophthalmologists. Impairment of corneal clarity is a significant cause of visual morbidity worldwide. Several highly mathematical treatises have been presented in support of different theories of corneal transparency in the normal cornea relating structure to function, particularly in the years since the advent of the electron microscope, which has brought about a much greater understanding of corneal ultrastructure. This review presents the concepts that underpin the theories of corneal transparency.
150 citations
TL;DR: The difference in activity of CNV in the two patients appeared to correlate with the quantity of membranous debris present, and changes common to both included a diffuse deposition of membrane coils external to the basement membrane of the retinal pigment epithelium.
Abstract: The purpose of this study was to describe the morphology of early choroidal neovascularisation (CNV) and compare the findings in two patients, in the first of whom the vessels appeared inactive and in the second progressive. Changes common to both included a diffuse deposition of membrane coils external to the basement membrane (BsM) of the retinal pigment epithelium (RPE), and macrophages and foreign body giant cells beneath thinned segments of Bruch's membrane (BrM). In the first patient small activated vessels surrounded by enlarged pericytes were found in the choroid beneath these areas and pursued a convoluted course, bulging into or through BrM, but without spreading in the sub-RPE space. This choroidal phase of CNV may be common and unrecognised. In the second patient there was spread of CNV in the sub-RPE space with extravasation of red cells and fibrin. The tips leaking fibrin were covered by a thick BsM-like material and naked endothelial cells were not seen. Pericytes were absent here but were observed at the non-leaking edge. The difference in activity of CNV in the two patients appeared to correlate with the quantity of membranous debris present.
123 citations
TL;DR: Test-retest variability of visual acuity measurements is lower using the ETDRS or probit methods than the traditional line assignment method.
Abstract: Purpose: The optimal method for scoring visual acuity measures is unknown. Our goal was to determine, in a clinical setting, the method of scoring visual acuity with the lowest test-retest variability. Methods: We investigated the effect of three different scoring methods using the Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity chart comparing 32 patients with macular disease and 38 age-matched normal subjects. All subjects completed six repetitions of ETDRS charts. Three scoring methods were then used (line assignment, ETDRS or letter-by-letter and probit), the results were converted to log MAR values and the test-retest variabilities analysed. Results: We found significant differences in variability among the three scoring methods (p<0.0001). The variability was greatest with the line assignment method and less with the ETDRS and probit methods. The ETDRS and probit methods had similar variabilities. The difference in variability between normals and patients was not statistically significant. There were no differences in the calculated visual acuities among the three methods, only the variabilities. Using the ETDRS or probit methods, the within-test standard deviation was about 0.04 log MAR units (two letters). Conclusion: Test-retest variability of visual acuity measurements is lower using the ETDRS or probit methods than the traditional line assignment method.
118 citations
TL;DR: Two mechanisms seem to contribute to this effect: relaxation of the ciliary muscle and changes in extracellular matrix, causing decreased resistance in the uveoscleral outflow routes.
Abstract: As there is no epithelial barrier between the anterior chamber and the ciliary muscle, aqueous humour may freely pass between the ciliary muscle bundles into the supraciliary and suprachoroidal spaces, from which it is drained through the sclera This uveoscleral outflow of aqueous humour accounts for 40-60% of the total outflow in monkeys, whereas it is considerably less in (3-8%) in cats and rabbits Direct measurements in human eyes have suggested that less than 15% is drained by the uveoscleral routes However, indirect calculations have given a value of about 35% in young adults and 3% in elderly persons (> 60 years) Under normal conditions, in monkeys, the uveoscleral outflow is insensitive to changes in the intraocular pressure, but cyclodialysis and experimental uveitis increase the uveoscleral outflow and make it more pressure sensitive The uveoscleral outflow is decreased by contraction (pilocarpine) and increased by relaxation (atropine) of the ciliary muscle Thus, changing the tone of the ciliary muscle may redistribute aqueous humour between the conventional and uveoscleral outflow routes Prostaglandins decrease the intraocular pressure by increasing the uveoscleral outflow Two mechanisms seem to contribute to this effect: relaxation of the ciliary muscle and changes in extracellular matrix, causing decreased resistance in the uveoscleral outflow routes
114 citations
TL;DR: Nine different amacrine cell types of cat, rabbit and human retinas are presently quite well studied in terms of morphologies, classification, mosaics, neurotransmitter content, neural circuitry and physiological responses to light.
Abstract: Since amacrine cells are important interneurons of the inner retina and their activity may be detected in certain waveforms of the electroretinogram, this paper reviews their morphologies, classification, mosaics, neurotransmitter content, neural circuitry and physiological responses to light. Nine different amacrine cell types of cat, rabbit and human retinas are presently quite well studied in terms of the aforementioned aspects and are described in detail in this paper.
113 citations
TL;DR: The uveal tract contains rich networks of both resident macrophages and MHC class II+ dendritic cells, and the role of these various cell types in immune homeostasis and ocular inflammation is briefly considered.
Abstract: Inflammatory and immune-mediated diseases of the eye are not purely the consequence of infiltrating inflammatory cells but may be initiated or propagated by immune cells which are resident or trafficking through the normal eye. The uveal tract in particular is the major site of many such cells, including resident tissue macrophages, dendritic cells and mast cells. This review considers the distribution and location of these and other cells in the iris, ciliary body and choroid in the normal eye. The uveal tract contains rich networks of both resident macrophages and MHC class II+ dendritic cells. The latter appear strategically located to act as sentinels for capturing and sampling blood-borne and intraocular antigens. Large numbers of mast cells are present in the choroid of most species but are virtually absent from the anterior uvea in many laboratory animals; however, the human iris does contain mast cells. Small numbers of what are presumed to be trafficking lymphocytes are present in the uveal tract of normal eyes. There is little data available on the presence or absence of eosinophils. The role of these various cell types in immune homeostasis and ocular inflammation is briefly considered.
100 citations
TL;DR: This paper is about the classification, diagnosis and management of dry eye and its message is that in recent years the authors have come to a far better under standing of the disease and now have more rational opportunities for therapy.
Abstract: INTRODUCTION Robert Doyne, Founder of the Oxford Congress, was born in 1857 and came to Oxford in 1886.1 He lived with his family at 53 Broad Street, not far from Keble College, which was later to become his college when he was appointed Margaret Ogilvie's Reader. Mrs Ogilvie, who created the readership, was married to one of the consulting ophthalmologists of that time. Doyne started the Oxford Eye Dispensary in a builder's yard, but shortly after, he established the Eye Hospital at 21-22 Wellington Square, now the site of the University Chest. It found its present site In Walton Street almost exactly 100 years ago, in the fever block of the Radcliffe Infirmary. Although after retirement Doyne moved to London, he died in Oxford following a stroke in 1916, in a house on the Woodstock Road, opposite to the church of St Phillip and St James. Doyne wrote over 87 papers and made a similar number of presentations in his clinical lifetime. At least one of these had implications for the topic of dry eye,2 the subject of this lecture. This paper is about the classification, diagnosis and management of dry eye and its message is that in recent years we have come to a far better under standing of the disease and now have more rational opportunities for therapy. To set the scene I will briefly describe some normal features of the tear system.
100 citations
TL;DR: These clinical and immunopathological features indicate that there is an underlying T-cell-mediated autoimmunity to uveal/retinal antigens in the development of these two forms of bilateral granulomatous uveitis.
Abstract: Although the inciting events in the pathogenesis of sympathetic ophthalmia and Vogt-Koyanagi-Harada (VKH) syndrome are different, these two forms of bilateral, granulomatous uveitis share several clinical, histopathological and immunohistochemical features, including their association with HLA types and in their in vitro T-cell response to retinal antigens. These clinical and immunopathological features indicate that there is an underlying T-cell mediated autoimmunity to uveal/retinal antigens in the development of these forms of uveitis. Both forms exhibit preservation of the choriocapillaris and retina despite extensive inflammatory cell infiltration in the choroid. Recent experimental studies suggest that this preservation of choriocapillaris could be the result of anti-inflammatory products secreted by the retinal pigment epithelium, including transforming growth factor-beta and a novel protein called retinal pigment epithelial protective protein that is known to suppress the phagocyte generation of superoxide. Such suppression of the oxidant release in the choroidal inflammation could help protect the uvea from necrotic change and preserve the choriocapillaris from inflammatory cell infiltration.
100 citations
TL;DR: The pattern electroretinogram (PERG) has now been in routine clinical use for sufficiently long to allow a personal clinical review of its relationship to the cortically generated pattern visual evoked potential (PVEP).
Abstract: The pattern electroretinogram (PERG) has now been in routine clinical use for sufficiently long to allow a personal clinical review of its relationship to the cortically generated pattern visual evoked potential (PVEP). The PERG and PVEP findings are presented from 520 eyes with optic nerve demyelination (382 eyes), optic nerve compression (90 eyes) or heredo-familial optic atrophy (48 eyes), and these are compared with the findings obtained in 223 eyes with dysfunction anterior to the retinal ganglion cells. Dysfunction anterior to the retinal ganglion cells gives a reduction in the P50 component of the PERG, but this component is usually spared in optic nerve disease where selective loss of the N95 component is by far the most frequently occurring abnormality. A diagnostic strategy is presented.
96 citations
TL;DR: While the grade of haze showed no relevant differences between the two groups, scar tissue was found histologically in the mitomycin group in only 1 of 8 corneas compared with 5 of 8 in the BSS group.
Abstract: Sixteen eyes of eight rabbits were randomised to either mitomycin C or Balanced Salt Solution (BSS) application after photorefractive keratectomy (PRK). Regular examinations of wound healing and haze were performed with the slit lamp. The animals were killed between 1 and 26 weeks after treatment, and the corneas examined by light and electron microscopy. While the grade of haze showed no relevant differences between the two groups, scar tissue was found histologically in the mitomycin group in only 1 of 8 corneas compared with 5 of 8 in the BSS group. A marked reduction in keratocytes in all mitomycin-treated corneas and a normal density of keratocytes in the BSS group was observed. Mitomycin reduced the number of keratocytes in the treated corneas, leading to less scar formation but not to a reduction in haze. Since no morphological correlate has been found, haze remains unexplained in the mitomycin-treated corneas.
TL;DR: It is apparent that most primary care doctors view their undergraduate ophthalmic medical education as inadequate and this is reflected in their confidence and understanding, and it is strongly suggested that general Ophthalmic education is aimed at teaching examination techniques and ophthalmological principles suitable for primary care practice.
Abstract: Purpose: To gain an insight into the adequacy of ophthalmic medical education for doctors in the primary care setting. Methods: A short forced-choice questionnaire was set to 150 randomly selected primary care practitioners in and around Bristol. Information was collected in relation to undergraduate and postgraduate ophthalmic education, ophthalmic confidence, facilities and understanding. Results: One hundred and thirty-three primary care doctors replied to the questionnaire of whom 35% were fundholders and 47% in training practices. Only 22% of all respondents felt their undergraduate ophthalmic medical education to be adequate. However, 83% of the 86 primary care doctors who had attended postgraduate update courses in ophthalmology felt these to be adequate. Despite the availability of an ophthalmoscope and distance vision chart, only 56% felt confident with the ophthalmoscope and only 61% reported that their distance chart was set up in accord with manufacturer's instructions. Seventy-one per cent of respondents reported having access to dilating agents but only 61% felt confident using them. Understanding of two key ophthalmic terms was also poor. Despite the general satisfaction, attendance of postgraduate update courses did not appear to alter facilities, confidence or understanding. Conclusions: It is apparent that most primary care doctors view their undergraduate ophthalmic medical education as inadequate and this is reflected in their confidence and understanding. Postgraduate courses, although more favourably received, do not appear to alter these findings. We strongly suggest, therefore, that general ophthalmic education is aimed at teaching examination techniques and ophthalmological principles suitable for primary care practice.
TL;DR: Comparison of these results with those of a previous audit carried out at this hospital 23 years ago suggests little improvement in the success rate of primary surgery, but the improvement in final retinal reattachment has been rather greater than previously suggested.
Abstract: SUMMARY Purpose: To define the current success rate of primary retinal detachment repair at one centre. Methods: One hundred and fifty-three consecutive patients undergoing surgery for primary retinal detach ments over a 6 month period were studied prospect ively. Data sheets were completed immediately after surgery and at final follow-up. One hundred and twenty-seven patients completed 6 months of follow up. Follow-up data on the remainder were obtained from the referring unit or directly from the patients by telephone. The term primary success was used to describe persisting retinal reattachment after a single operation. Multiple logistic regression was carried out to establish factors associated with failure. Results: One hundred and twenty-three patients (80 %) had persisting retinal reattachment after a single procedure. Of the 30 patients who required further surgery, in 5 the retina remained detached at final follow-up. The final anatomical success rate was 97%. New or missed breaks were the major causes of failure of primary surgery. Failure of primary surgery was associated with the presence of highly elevated breaks ({3 = 0.11, P = 0.03). No other pre-operative factors appeared to predict failure to reattach the retina. Conclusions: Comparison of these results with those of a previous audit carried out at this hospital 23 years ago suggests little improvement in the success rate of primary surgery (75% vs 80%). The improvement in final retinal reattachment has been rather greater (from 88% to 97%). The major impact of recent technical advances in retinal reattachment surgery has been on the success rate of reoperations after failed primary surgery.
TL;DR: It is concluded that susceptibility to EAU is connected with a Th1-dominant response, but resistance can involve either a ‘null’, F344-like response (Th1-low/Th2-low) or a Th2-Dominant response.
Abstract: This study addresses the question whether susceptibility versus resistance to experimental autoimmune uveoretinitis (EAU) is connected to a Th1-type (interferon-gamma high, interleukin-4 low), versus a Th2-type (IFN-gamma low, IL-4 high) response. Primed lymph node cells of susceptible Lewis rats produced IFN-gamma in response to antigen in culture and transferred EAU to syngeneic recipients, whereas lymph node cells of resistant F344 rats made no IFN-gamma and did not transfer disease. Reversal of the disease pattern, by treatment of F344 rats with B. pertussis toxin and immunisation of Lewis rats with antigen in incomplete Freund's adjuvant, resulted in a parallel reversal of these response patterns. Neither strain produced significant IL-4 responses. A study of the response patterns in mice confirmed that high Th1 responders were susceptible, whereas low Th1 responders and Th2 responders were resistant. We conclude that susceptibility to EAU is connected with a Th1-dominant response, but resistance can involve either a 'null', F344-like response (Th1-low/Th2-low) or a Th2-dominant response.
TL;DR: This primary neurogenerative disorder presents with diabetes mellitus and progressive optic atrophy, probably due to pathology in the optic nerve, and found no evidence of mitochondrial genome defects or rearrangements.
Abstract: Wolfram syndrome is the association of diabetes mellitus and optic atrophy, also called DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy and deafness). Incomplete characterisation has caused diagnostic confusion; we therefore undertook a nationwide cross-sectional case finding study. We identified 45 patients with Wolfram syndrome, median age 29 years. All patients fulfilled the ascertainment criteria (juvenile onset diabetes mellitus and optic atrophy). Optic atrophy presented in 38 patients with reduced visual acuity and colour vision defect (median age 11 years), progressing to visual acuity of 6/60 or less in 35 patients (median time 8 years, range 1-25 years). Visual field examinations recorded before acuity deteriorated showed central scotomas with peripheral constriction. Blind patients had absent pupillary reflexes. Horizontal nystagmus was seen in patients with other signs of cerebellar degeneration. There was no pigmentary retinal dystrophy; only 3 patients had background diabetic retinopathy, despite a median duration of diabetes of 24 years. Electroretinography was normal in 3 patients and showed reduced amplitude in 3 patients; visual evoked responses were abnormal (10/10 patients: reduced amplitude to both flash and pattern stimulation). Magnetic resonance imaging showed generalised brain atrophy with reduced signal from the optic nerves and chiasm. A postmortem brain specimen from one patient revealed atrophy of the optic nerves, chiasm, cerebellum and brainstem. We found no evidence of mitochondrial genome defects or rearrangements. This primary neurogenerative disorder presents with diabetes mellitus and progressive optic atrophy, probably due to pathology in the optic nerve.
TL;DR: There is evidence to suggest that prognostically significant microcirculatory patterns may be detectable by non-invasive imaging techniques that may provide a substitute for biopsy to guide the clinical management of patients with these sight- and life-threatening tumours.
Abstract: The microcirculation of ciliary body and choroidal melanomas is remodelled into patterns. The presence of microvascular networks, composed of back-to-back loops that encircle microdomains of tumour, and parallel vessels with cross-linking, are associated with death from metastatic melanoma. The formation of these complex vascular patterns may result from reciprocal interactions between the tumour cell and the extracellular matrix, and pattern formation may reflect an invasive tumour cell phenotype. Ciliary body and choroidal melanomas are among the few forms of cancer treated before a pathologist assigns a grade to indicate whether tumour is likely to follow a benign or aggressive course. There is evidence to suggest that prognostically significant microcirculatory patterns may be detectable by non-invasive imaging techniques that may provide a substitute for biopsy to guide the clinical management of patients with these sight- and life-threatening tumours.
TL;DR: Endothelial cell monolayer attenuation and keratocyte loss are consistent findings in grafts removed subsequent to clinically observed endothelial rejection, which suggests death of donor corneal cells is mediated, at least in part, by apoptosis.
Abstract: Infiltrating inflammatory cell phenotypes and apoptosis in rejected human corneal allografts
TL;DR: It is believed that corneal wedge excision offers an excellent surgical result for patients with PMD, although modification of the technique may be required to improve long-term astigmatic drift.
Abstract: Purpose: A retrospective study reporting long-term visual and astigmatic results of patients with pellucid marginal degeneration (PMD) treated by corneal wedge excision. Methods: The notes of 9 patients (10 eyes) treated by corneal wedge excision were reviewed. All patients had typical PMD and were treated by excision of an inferior crescent of diseased corneal tissue. The excised area measured approximately 2 mm in width and extended from the 4 o'clock to the 8 o'clock meridian. All thinned corneal tissue was removed. Normal-thickness corneal stroma was then reapposed with 10/0 nylon or 10/0 polypropylene sutures. Post-operative selective suture removal was performed until a satisfactory visual and astigmatic result was achieved. This was guided by refraction, keratometry and photo-keratoscopy results. Pre-operative best corrected visual acuity ranged from 6/12 to 6/60 with an associated mean keratometric astigmatism of =13.8 dioptres (range 8–25 dioptres, axis range 30°–175°). Mean follow-up was 59 months (range 14–138 months). Results: Post-operatively a stable corrected visual acuity of 6/9 or better was achieved in all cases in a mean time of 5.4 months (range 3–12 months). Mean post-operative keratometric astigmatism was 1.4 dioptres (range 0.5–4 dioptres). Over the course of follow-up long-term astigmatic drift (LTAD) was noted, mean 2.1 dioptres (range 0.5–5.5 dioptres). Three patients developed mild inferior pannus related to peripherally sited sutures. One case developed apparent corneal hydrops within the corneal wound after 9 years of follow-up. Conclusions: We believe that corneal wedge excision offers an excellent surgical result for patients with PMD, although modification of the technique may be required to improve long-term astigmatic drift.
TL;DR: A retrospective, hospital-records-based study of neonates screened for retinopathy of prematurity (ROP) was undertaken to determine whether the inclusion criteria for screening could have been safely altered to reduce the numbers of babies screened whilst not missing any stage III disease.
Abstract: A retrospective, hospital-records-based study of neonates screened for retinopathy of prematurity (ROP) was undertaken to determine whether the inclusion criteria for screening could have been safely altered to reduce the numbers of babies screened whilst not missing any stage III disease. Babies from six neonatal intensive care units in Birmingham were screened by a single examiner. Between November 1989 and November 1995, 1611 babies were examined and 1429 of these fell within the inclusion criteria of current guidelines for ROP screening produced by the Royal College of Ophthalmologists and the British Association of Perinatal Medicine--any baby < or = 1500 g birthweight or < or = 31 weeks gestational age. Thirty-nine (39) babies developed stage III ROP of which 31 (2.2%) were from Birmingham. In addition 8 babies with stage III ROP were referred from elsewhere. All 39 babies with stage III ROP had a birthweight < or = 1250 g or a gestational age of < or = 29 weeks, but 2 fell outside one criterion, indicating the need for both to be used. Had these inclusion criteria been utilised during this period, then 30% fewer babies would have been examined (432 of 1429). The importance of using both birthweight and gestational age as inclusion criteria is discussed, and the dangers of altering the indications for national screening on the basis of one study population is emphasised.
TL;DR: The results show that the Pelli-Robson chart and the Cambridge gratings are good measures of medium to low spatial frequencies, as would be predicted from their design, while the Regan and UW charts correlated with medium to high frequencies.
Abstract: Purpose: Contrast sensitivity (CS) testing using chart tests of CS is becoming increasingly common in low vision assessment. Yet we know little about the validity of these charts, i.e. which region of the spatial frequency spectrum is being measured. In this study we aimed to determine the validity of currently available CS charts by comparison against oscilloscope-based CS. We also determined their relative ability to predict reading speed. Methods: CS was measured with five commercially available charts and the contrast sensitivity function was determined with sinusoidal gratings presented on a Joyce screen using a two-alternative forced choice staircase technique in 36 observers with low vision and 3 with normal vision. Reading rate was also measured with the subject reading with his or her own optical low vision aid. Results: The results show that the Pelli-Robson chart and the Cambridge gratings are good measures of medium to low spatial frequencies, as would be predicted from their design, while the Regan and UW charts correlated with medium to high frequencies. The Vistech chart was a good predictor of CS at each spatial frequency. Conclusions: The best chart test of CS depends on which region of the CS curve is of interest. All the charts were good predictors of reading rate.
TL;DR: These unique population-based results provide new insight into the natural history of AMD in an elderly population using randomly encoded photographs from a geographically defined random population sample of elderly people in 1982-4.
Abstract: SUMMARY Despite age-related macular degeneration (AMD) being the commonest cause of blindness amongst the elderly in Western society, the incidence of new lesions is poorly docnmented and the natural history of existing disease remains ill understood. Purpose: To document in an elderly population the incidence of new AMD lesions and the progression of pre-existing AMD over time. Method: Baseline ophthalmic examinations were per formed on a geographically defined random population sample of elderly people in 1982-4, and retinal photographs taken. The present study re-examined md re-photographed survivors after approximately 7 years using the same fundus camera. Photographs were randomly encoded, and independently graded for AMD features by two masked observers using the Wisconsin AMD grading system. Disagreements were resolved by review to reach a consensus. Results: Eighty-two of the 88 participating survivors had photographs of gradable quality on both occasions in at least one eye. Mean age at foJ)ow-up was 87 years (range 84-97 years) and 70.7% of subjects were female. Paired photographs were available on 158 eyes, and showed important differences in drusen type, drusen area and characteristics of the retinal pigment epithe lium (RPE) between initial and subsequent examina ions. The 7 year incidence (and regression) of lesions was: drusen 30.6% (20.0%), RPE degeneration 54.5% (8.8%), increased pigment 11.6% (64.7%), subretinal ltaemorrhage 1.3%, subretinal scar/fibrin 1.3% and coograpbic study 1.3%.
TL;DR: In this paper, the authors investigated the surgical results in 25 patients identified with malignant (ciliary block) glaucoma and concluded that surgical vitrectomy in the presence of an intact posterior capsule may preclude the surgical resolution of aqueous misdirection.
Abstract: We investigated the surgical results in 25 patients identified with malignant (ciliary block) glaucoma. Four of these patients (16%) had successful outcomes following laser treatment alone. Nineteen patients (76%) underwent microsurgery for glaucoma refractory to conventional medical and/or laser therapy and are the subjects of this study. Core vitrectomy was successful in 4 of 6 pseudophakic patients (67%) and in 1 of 4 phakic patients (25%). Combined cataract extraction and vitrectomy had a higher success rate in patients undergoing posterior capsulectomy at the time of surgery (5 of 6 patients; 83%) compared with those patients left with an intact posterior capsular bag (1 of 4 patients; 25%). Intracapsular cataract extraction was successful in 1 of 2 patients (50%). We conclude that surgical vitrectomy in the presence of an intact posterior capsule may preclude the surgical resolution of aqueous misdirection. In eyes with pre-existing cataract, we recommend combined lens extraction, primary posterior capsulectomy and surgical vitrectomy for the surgical management of phakic malignant glaucoma.
TL;DR: Botulinum toxin is a highly effective temporary treatment for involutional entropion with few complications and no adverse effects on the results of surgical entropions repair.
Abstract: Purpose: A prospective study was designed to evaluate the use of botulinum toxin as a temporary treatment in patients awaiting surgical repair for involutional entropion and to compare its use with lid taping. Methods: Botulinum toxin was administered to 30 patients with involutional entropion (35 eyelids). These patients had all previously been using lid taping and lubricant ointment as a temporary measure whilst awaiting lid surgery. Patients' symptoms and signs were assessed before and after toxin injection. The date of entropion recurrence was recorded. Eyelid tissue from 8 patients treated with toxin and 3 control patients who had not been given toxin was obtained after surgical entropion repair and examined histologically to ensure the botulinum toxin had no potential detrimental effects on the results of surgery. Results: The toxin was simple and quick to administer. Anatomical success was achieved in 33 of the 35 eyelids with significant improvements in symptoms and signs. The mean duration of action of the toxin was 12.5 weeks. Lower lid laxity was inversely correlated with duration of toxin action. There were no consistent changes in orbicularis oculi morphology after toxin injection. Conclusion: Botulinum toxin is a highly effective temporary treatment for involutional entropion with few complications and no adverse effects on the results of surgical entropion repair.
TL;DR: The abnormality in choroidal perfusion indicated by a reduction in OPA in all LTG patients is unrelated to the presence or absence of vasospasm.
Abstract: Purpose: A vascular basis for the pathogenesis of primary open angle glaucoma has been postulated for many years. Defects in the regulation of ocular blood flow may be the initiating factor in this group of multifactorial diseases. This study was designed to evaluate the effect of vasospasm on ocular pulse amplitude (OPA) in low tension glaucoma (LTG) patients. Methods: OPA, using the Langham Ocular Blood Flow (OBF) System, applanation intraocular pressure (IOP), systemic blood pressure and heart rate were measured and vasospasm was determined by a fingernail capillary blood flow test. Results: OPA (mmHg) in the LTG patients with a vasospastic reaction (LTG-V, 1.4 ± 0.1, n= 17) was not significantly (p>0.09) different when compared with non-vasospastic LTG patients (LTG-NV, 1.5 ± 0.2, n= 15) but was significantly (p 0.05) different when compared with each other, but was significantly (p<0.05) lower when compared with matched control subgroups (15.0 ± 0.3 and 15.2 ± 0.4, respectively). Haemodynamic parameters were not significantly different from controls. Conclusion: The abnormality in choroidal perfusion indicated by a reduction in OPA in all LTG patients is unrelated to the presence or absence of vasospasm.
TL;DR: Although retinopathy can occur in a tamoxifen-treated population its low incidence and an associated good prognosis for vision does not merit special screening for this problem.
Abstract: Purpose: This study was undertaken to estimate the incidence of retinal changes and determine the prevalence of ocular toxicity associated with tamoxifen treatment in a breast cancer population. Methods: The study was based on a population cross-sectional survey, including 290 patients taking tamoxifen from 6 months to 12 years; 274 patients were analysed. The main outcome measures were the incidence of retinal changes and visual impairment. Results: The incidence of retinal changes was 0.9% (3 of 274 patients). All 3 patients were asymptomatic. The length of tamoxifen treatment ranged from 39 months to 120 months in the affected patients, with cumulative tamoxifen doses ranging from 23.7 g to 73 g. Conclusions: Retinopathy in patients receiving low doses of tamoxifen is rare and, in our study, did not result in changes in visual acuity. We found no retinopathy in patients receiving tamoxifen within the first 3 years of treatment or in patients receiving a total tamoxifen dosage of less than 23.7 g. Although retinopathy can occur in a tamoxifen-treated population its low incidence and an associated good prognosis for vision does not merit special screening for this problem.
TL;DR: The mechanisms by which cyclosporine exerts both its immunomodulatory and its lacrimogenic actions are examined to determine whether these effects are truly local or are influenced by generalised immunosuppression caused by systemic absorption of topically applied drug.
Abstract: Topical cyclosporine has been used by veterinary ophthalmologists since 1989 for the treatment of ocular surface inflammatory disease and keratoconjunctivitis sicca (KCS). As well as ameliorating clinical signs of ocular surface lymphocyte-driven inflammation in the dog, cat and horse, topical cyclosporine significantly raises tear production in both normal and KCS-affected animals. A licensed ointment preparation of 0.2% cyclosporine, Optimmune (Schering-Plough), is now available for administration to dogs. In this paper we examine the mechanisms by which cyclosporine exerts both its immunomodulatory and its lacrimogenic actions. The pharmacokinetics of topical cyclosporine are examined to determine whether these effects are truly local or are influenced by generalised immunosuppression caused by systemic absorption of topically applied drug. The paper reviews the few side effects of cyclosporine preparations in the experience of veterinary ophthalmologists and the experimental evidence which appears to implicate the vehicle rather than the active agent cyclosporine as causing many of these effects. Given that topical cyclosporine has been so widely accepted as a valuable ophthalmic preparation in the veterinary world and licensed as such, it is surprising that human ophthalmologists have not employed the drug to the same extent for conditions from vernal keratoconjunctivitis to Sjogren's syndrome.
TL;DR: There has been a change in the causation of childhood eye injuries in the country compared with reports of 25 years ago, and the visual outcome in patients was worse than in reports from developed countries.
Abstract: Two hundred and twenty-eight children of both sexes (152 males and 76 females) aged between 1 and 15 years treated for eye injuries at the University of Nigeria Teaching Hospital, Enugu, Nigeria were studied. The injuries were commonly sustained during domestic activities (29.8%), at play or sports (23.7%), in the schoolroom (16.7%) and during farm work (10.1%). Causative agents were mostly sticks, followed by stone missiles and other flying objects. There was a general delay in reporting to hospital in all types and degrees of severity of injuries, with only 28.5% reporting in the first 24 hours and as many as 10.5% after 1 month. How quickly the patient came to hospital was determined more by social and economic factors than by sex, age and type of injury. Visual outcome was best in patients with mild non-penetrating injuries and worst in those with severe penetrating injuries. Amongst the latter the outcome was worse when the posterior segment was involved than when the injury involved only the anterior segment. Our study showed that there has been a change in the causation of childhood eye injuries in the country compared with reports of 25 years ago. The visual outcome in our patients was worse than in reports from developed countries. This was due mainly to delay in seeking specialist treatment and lack of sophistication of the treatment, especially in severe cases.
TL;DR: In this article, E-cadherin was found to be present in all layers of the conjunctival epithelium, but not in corneal epithelialium, which may indicate that factors other than Ecadhrin binding determine the distribution of HML-1+ IELs.
Abstract: The conjunctival mucosa has several similarities to the mucosal immune system of the gut and bronchus Like the gut and bronchial mucosa, the conjunctiva is capable of inducing tolerance to encountered antigens and possesses a repertoire of CD8+ intraepithelial lymphocytes (IELs) bearing the human mucosal lymphocyte-1 antigen (HML-1) which has been shown to be an alpha E beta 7 integrin The epithelial cells surface ligand for HML-1 is E-cadherin The distribution of E-cadherin in the normal human conjunctiva and cornea is not known We investigated E-cadherin distribution in the conjunctiva and cornea by immunohistochemistry E-cadherin was found to be present in all layers of the conjunctival epithelium but not in corneal epithelium In the conjunctiva it may act as a ligand for the HML-1+ IELs The specific location of IELs along the basal cells of the conjunctiva compared with the generalised distribution of E-cadherin through all layers, indicates that factors other than E-cadherin binding determine the distribution of HML-1+ IELs We performed electron microscopy on de-epithelialised conjunctival and corneal samples We demonstrated the presence of epithelial basement membrane pores in the conjunctiva but not in the cornea Lymphocyte migration from the substantia propria to the intraepithelial compartment appears to occur through these pores, which may also serve as a conduit for antigen presentation by epithelial antigen presenting cells (APCs) to lymphocytes in the substantia propria
TL;DR: 5 cases that illustrate the diverse ocular manifestations of NF2 are described that are rarely appreciated and are often the first sign of disease.
Abstract: Neurofibromatosis 2 (NF2) is an inherited disorder characterised primarily by bilateral vestibular schwannomas and other central nervous system tumours. Individuals with NF2 also have early onset cortical and posterior subcapsular or capsular cataract and other ocular abnormalities, such as retinal hamartomas. Although their diagnostic significance is rarely appreciated, the ocular manifestations are often the first sign of disease. We describe 5 cases that illustrate the diverse ocular manifestations of NF2.
TL;DR: The view that RVO is a contraindication to the use of the OCP is supported, as patients who sustain RVO may continue with their HRT, as HRT is not a major single risk factor for RVO.
Abstract: Retinal vein occlusion (RVO) is most commonly seen in middle-aged or older patients and is associated with underlying cardiovascular risk factors. It is much less common in younger patients. Use of the oral contraceptive pill (OCP) is known to be a risk factor for cardiovascular and cerebrovascular disease. There have previously been a few isolated case reports of patients sustaining an RVO whilst taking the OCP. The aim of this study was to investigate patients sustaining an RVO whilst taking the OCP or hormone replacement therapy (HRT). From a large series of 588 patients, we found 11 with an RVO associated with sex hormone preparations. Of these, 6 had taken the OCP and 5 were HRT users. From this large group there were only 9 female patients aged under 35 years who sustained an RVO. Of these, 6 were associated with use of the OCP. All patients were investigated for recognised medical risk factors for RVO. None of these factors were identified in the patients who had used the OCP. Of the patients taking HRT, 4 of the 5 had other potential risk factors. From our large series, the prevalence of RVO in female patients under 35 years taking the OCP was 66%. There is a 30% uptake of the OCP in the general population. These data support the view that RVO is a contraindication to the use of the OCP. Additionally, it would appear (albeit from limited data) that patients who sustain RVO may continue with their HRT, as HRT is not a major single risk factor for RVO.