Showing papers by "Moorfields Eye Hospital published in 1993"

Mutations in the human retinal degeneration slow (RDS) gene can cause either retinitis pigmentosa or macular dystrophy.

Abstract: Mutations in the RDS gene have been sought in families with autosomal dominant retinal dystrophies. A cysteine deletion at codon 118/119 is associated with retinitis pigmentosa in one. Three families with similar macular dystrophy have mutations at codon 172, arginine being substituted by tryptophan in two and by glutamine in one. A stop sequence at codon 258 exists in a family with adult vitelliform macular dystrophy. These findings demonstrate that both retinitis pigmentosa and macular dystrophies are caused by mutations in the RDS gene, and that the functional significance of certain amino-acids in peripherin-rds may be different in cones and rods.

A review of 72 consecutive cases of Acanthamoeba keratitis, 1984-1992.

Abstract: A review of consecutive cases of Acanthamoeba keratitis presenting since 1984 was undertaken in order to assess prognostic factors, the success of culture procedures and the outcome of medical and surgical management, with reference to current clinical practice. Seventy-two consecutive cases (77 eyes) of Acanthamoeba keratitis have been managed. Sixty-four patients were contact lens wearers, 28 of these wearing disposable lenses. Superficial corneal involvement and perineural infiltrates were common in those diagnosed less than a month after first symptoms, designated 'early' presentation. Ring infiltrates and ulceration with stromal lysis characterised those presenting at 1-2 months ('intermediate') or after 2 months ('late'); these groups also progressed more frequently to hypopyon, scleritis, glaucoma and cataract formation. Positive corneal cultures were obtained in 10 of 14 (71%) intermediate and 17 of 23 (74%) late cases; early cases underwent epithelial biopsy but formal trephine biopsy was not usually justified (1 of 35 cases) and only 19 of 35 (54%) were tissue-positive. Microbial co-isolates were obtained from 20 corneas. Thirty-four penetrating keratoplasties were performed in 23 eyes, 21 whilst inflamed and 13 when quiet. Of 13 failures in inflamed eyes, 9 were due to recurrence of Acanthamoeba infection. Medical cure is known to have been achieved in 64 of 73 (88%) eyes, 4 of the original 77 having been lost to follow-up abroad. Fifty-eight of 73 eyes (79%) achieved a final visual acuity of 6/12, and of the culture-positive cases, 32 of 46 (70%) achieved 6/12.(ABSTRACT TRUNCATED AT 250 WORDS)

Symptomatic abnormalities of dark adaptation in patients with age-related Bruch's membrane change.

Abstract: Some patients with age-related changes at the level of Bruch's membrane and good visual acuity report poor vision in dim light, fading vision in bright light, and a central scotoma noticeable in the dark. Ophthalmic examination, scotopic thresholds, and dark adaptation kinetics were recorded in 12 eyes of 12 patients with such symptoms. All had macular drusen which were hypofluorescent on fluorescein angiography in nine subjects, and six had evidence of prolonged choroidal filling on fluorescein angiography. Scotopic thresholds were depressed in six patients who all experienced a central scotoma in the dark or poor night vision. The kinetics of dark adaptation were abnormal in all 10 patients in whom reliable measurements were possible. The findings suggest that visual symptoms reflect abnormality of both scotopic sensitivity and the time course of dark adaptation in patients with age-related Bruch's membrane change.

Limbal transplantation in the management of chronic contact-lens-associated epitheliopathy.

Abstract: We describe the clinical management of 6 patients who developed a chronic corneal epitheliopathy 1-18 years after commencing soft contact lens wear. All had a history of exposure to thiomersal in contact lens fluids. The corneal changes were characterised by epithelial haze and superficial stromal vascularisation which extended from the limbus towards the visual axis. Five patients were observed for a minimum of 18 months after stopping contact lens wear before undergoing limbal transplantation. A good result was obtained in 1 patient who had worn a contact lens in one eye only. Recurrent epithelial changes were observed on the recipient eyes of the remaining patients who had previously worn contact lenses bilaterally, and in 1 patient epithelial haze also developed adjacent to the donor site in the previously clinically normal donor eye. All 5 patients experienced an improvement in symptoms post-operatively but in 2 patients the visual acuity later deteriorated because of epithelial irregularity. The sixth patient has not had surgery. We conclude that limbal stem cell dysfunction in chronic contact-lens-associated epitheliopathy may be subclinical and that autograft transplantation in bilaterally exposed patients may fail to restore the epithelial phenotype of the host eye whilst jeopardising the epithelial integrity of the donor eye by depleting its stem cell reserve.

Adverse effects of topical antiglaucomatous medications on the conjunctiva.

Abstract: With selected patients glaucoma filtration surgery is highly successful. However, there is growing evidence that chronic topical medical therapy has a deleterious effect on surgical outcome. It has been suspected that topical drugs exert an adverse effect on the conjunctiva which results in altered postoperative wound healing. In this review the effect of previous topical antiglaucoma medication on the conjunctiva and the outcome of subsequent glaucoma filtration surgery are discussed.

The casual level of meibomian lipids in humans

Abstract: Using a modified skin surface lipid measuring instrument, the Meibometer, the amounts of meibomian lipid on the lid margins (the casual levels) of 421 subjects aged 1 to 94 years were measured. The lowest levels were found in children younger than 14 years (means +/- S.E.: males = 1.48 +/- 0.17, females = 1.53 +/- 0.17 micrograms lipid/mm2 lid margin surface) and rose with age, the highest levels being found in males aged 60-69 years (mean +/- S.E. = 3.26 +/- 0.18 micrograms lipid/mm2 lid margin surface). Male levels were higher than females in the 20-29 years age group but male and female levels became indistinguishable above the age of 50. These age- and sex-related changes differed markedly from those seen in skin surface lipid levels. The age-related changes in the casual levels of lid lipids remain unexplained although an endocrinological mechanism modified by morphological factors is considered.

Conjunctival autografting in the surgical management of pterygium

Abstract: In a retrospective survey of 117 operations for primary or recurrent pterygium, conjunctival autografting was compared with both excision without conjunctival closure ('bare sclera excision') and excision with complete conjunctival closure. The probability of corneal recurrence at 36 months after surgery was determined by survival curve analysis. In previously unoperated cases conjunctival autografting (n = 15) resulted in a 14% probability of recurrence, compared with 70% for bare sclera excision (n = 50) and 69% for excision with complete conjunctival closure (n = 20). In previously operated cases conjunctival autografting (n = 17) resulted in a 7% probability of recurrence, compared with 82% for bare sclera excision (n = 15). Hazard ratio analysis confirmed the statistical significance of these results at the 95% confidence level. Conjunctival autografting was more likely to produce an improvement in visual acuity than other forms of surgery.

Primary vitrectomy for rhegmatogenous retinal detachment

Abstract: One hundred and twenty-four eyes with a rhegmatogenous retinal detachment, considered to be at high risk of failure if treated conventionally, underwent vitrectomy and internal tamponade, with or without scleral buckling, as the primary procedure The retina was reattached in 645% of eyes after one operation, 750% after two, and in 83% of eyes after more than two operations, with no difference in the success rate between those eyes which underwent vitrectomy alone, and those that received adjunctive scleral buckling; duration of surgery was significantly shorter, however, in the former group Twenty percent of eyes redetached in association with proliferative vitreoretinopathy, and 20% of phakic eyes developed posterior subcapsular lens opacities after surgery Vitrectomy is now an established method in the management of selected cases of rhegmatogenous retinal detachments

A new locus for autosomal dominant retinitis pigmentosa on chromosome 7p.

Abstract: Autosomal dominant retinitis pigmentosa (adRP) is known to result from mutations in two different retinal genes-rhodopsin and peripherin-while a third locus has been implicated by linkage data. However, families have been reported in which all three known loci have been excluded. We report linkage of adRP in one such family to two microsatellite markers on chromosome 7p. D7S435 has previously been localized to 7p13-15.1; D7S460, previously only localized to chromosome 7, maps to within 2 cM of D7S435 with a lod score of 12.15. Two point linkage analysis between these markers and adRP gave lod scores of 5.65 (theta = 0) and 4.19 (theta = 0.046) for D7S460 and D7S435, respectively. Multipoint analysis gave a maximum lod score of 8.22. These data strongly suggest a new adRP locus on chromosome 7p.

Ophthalmic herpes zoster.

Abstract: A current review of ophthalmic zoster is presented including its virology, immunology, epidemiology and pathogenesis. We give our findings in 1356 patients referred to the Zoster Clinic at Moorfields Eye Hospital, London. The treatment of the disease and its ocular complications is discussed.

Photorefractive keratectomy: implications of corneal wound healing.

Abstract: Photorefractive keratectomy (PRK) with an argon fluoride laser (193 nm) was developed to alter the refractive power of the eye predictably and permanently. At PRK the central corneal epithelium is debrided mechanically and a disc 4 to 6 mm in diameter is ablated into the anterior stroma using computer controlled algorithms to control the depth of the wound. Theoretically for corrections of up to -7 dioptres less than 10% of the axial corneal thickness is removed.' As there is little loss of corneal strength and miniimal tissue distortion during surgery, reproducibility is enhanced, producing a potentially superior refractive technique to radial keratotomy. Initial enthusiasm for PRK was based on the remarkable precision and smoothness of the ablated surface\"A which it was hoped would be translated to an accurate change in refraction. An ideal result would be achieved if the corneal epithelium then assumed the contour of the ablated surface and there was no stromal regeneration. However, it is now apparent that an initial period of overcorrection is followed by regression to a relatively stable refraction and that in a proportion of cases stromal scarring can produce glare and a loss of best corrected visual acuity.--' Despite the precision of the PRK ablation the accuracy of the final refraction is at present only comparable to radial keratotomy. Accordingly 5 months after PRK approximately 55% of eyes have an unaided vision of 6/6, while 95% of eyes with -2-00 dioptres of error are within 1 dioptre of their intended refraction,7 but with considerable variation between individuals.578 This error in final refraction is due to the normal response of the cornea to an anterior keratectomy, which is to regenerate tissue to restore the integrity of the eye. Anterior stromal haze after PRK is thought to result from light scattered by scar tissue and has been shown to be more severe with increased ablation depth.5 7'\" Gartry et al detected a reduction in corneal transparency in 92% ofpatients, ofwhom 18% had lost one to two lines of best corrected Snellen acuity 1 year after surgery.7 Additionally, if a small ablation zone (4 mm) is used positive spherical aberration (creating a halo effect) occurs in conditions of reduced illumination as the pupil dilates past the edge of the ablation.57 Although these halos can be eliminated by using a larger ablation zone,7 this entails an increased depth of ablation with its associated increased risk of haze.8 A potential loss of transparency in the optical axis of an otherwise healthy eye must give cause for concern. Unfortunately, topical corticosteroid therapy following PRK has not been demonstrated to reduce subepithelial haze or regression significantly.8 Trials are therefore in progress to evaluate different postoperative regimens to minimise scar formation. As modification of the wound healing response may become an integral part of the management of patients following PRK it is opportune to review our current concepts of corneal scar formation.

Trauma-induced retinal detachment associated with giant retinal tears

Abstract: Giant retinal tears may arise spontaneously, but approximately 25% occur in association with ocular trauma. The clinical findings and results of surgical management in 38 cases of traumatic giant retinal tear seen at Moorfields Eye Hospital in London during a 10-year period are presented. Patients were young (mean age = 29 years) and mostly men (n = 36; 95%). Trauma was penetrating in 14 eyes (37%) and nonpenetrating in 24 (63%). Initial surgical management consisted of pars plana vitrectomy and fluid-silicone oil exchange in the majority of cases. Lensectomy was performed for opacity or dislocation in 23 (61%) eyes. Reattachment was achieved in 34 (89%) eyes 12 months after surgery. Most of the surgical failures occurred in eyes with penetrating trauma. Raised intraocular pressure was an associated problem that required treatment in 12 (32%) eyes. Visual acuity at final follow-up examination ranged from 6/6 to no perception of light (NPL; mean = 6/36). These results compare favorably with published figures for the treatment of spontaneous giant retinal tears.

Spared written naming of proper nouns: a case report.

Abstract: In this study we describe an investigation into the residual written word retrieval skills of M.E.D., a patient with a severe aphasia. M.E.D.'s performance on written naming and writing to dictation tasks showed a distinctive pattern of performance across semantic categories. The patient's ability to write the names of countries and famous people was consistently superior to her ability to write the names of objects. These results could be considered as indicative of a double dissociation in the proper nouns category, as there are already patients on record who have a selective deficit in retrieving proper nouns.

Alzheimer's Disease Families with Amyloid Precursor Protein Mutations

Abstract: Early onset Familial Alzheimer's Disease (FAD) is an autosomal dominant disease with apparent complete penetrance. It is genetically heterogeneous with some families carrying mutations in the amyloid precursor protein (APP) gene which segregate with the disease. In addition, there is allelic heterogeneity with four mutations associated with FAD. Three mutations have been reported at APP 717, just distal to the C-terminus of the beta-amyloid domain, APP 717 val-ile, APP 717 val-phe, and APP 717 val-gly, which are associated with autopsy-proven Alzheimer's disease (AD). APP 670/671 lies at the N terminus of the beta-amyloid domain and is associated with clinically diagnosed FAD in two Swedish families. FAD tends to have prominent myoclonus and this is shared by the cases with APP mutations. In two unrelated UK families with APP 717 val-ile mutations there was early prominent memory impairment with dyscalculia proceeding to generalized cognitive impairment with a lack of insight. There was a late development of a gait disturbance with extrapyramidal features in some members. Positron emission tomography (PET) with fluorodeoxyglucose demonstrated posterior bitemporal biparietal hypometabolism in one case. Magnetic resonance imaging (MRI) showed generalized cerebral atrophy particularly affecting the temporal lobes and hippocampus. At autopsy, a single case showed extensive beta-amyloid deposition with congophilic angiopathy and widespread senile plaques and neurofibrillary tangles. The cytoskeletal pathology associated with abnormally phosphorylated tau was similar to cases of sporadic AD. In addition, there were widespread cortical and subcortical Lewy bodies. A single family with the APP 717 val-gly mutation also showed prominent myoclonus, lack of insight, and seizures, PET, in a single case, showed classical biparietal bitemporal hypometabolism. Autopsy, in a single case, showed diffuse deposits of beta-amyloid throughout the cortex with frequent neuritic plaques and neurofibrillary tangles. No other inclusion bodies were seen. There was severe congophilic angiopathy. The age at onset of APP mutations is around 50 years of age by contrast to other early onset FAD pedigrees.

Sub-Tenon, Retrobulbar and Peribulbar Local Anaesthesia: The Effect Upon Intraocular Pressure

Abstract: Objectives: (1) To assess the safety of administration of a sub-Tenon fluid bolus directly contacting the globe, and compare it to posterior delivery by retrobulbar injection. (2) To assess the effect of differing volumes of anaesthetic solution administration upon intraocular pressure for sub-Tenon, retrobulbar and peribulbar administration. Study Design: (1) Intraocular pressure assessment by Perkins applanation tonometry, immediately prior to and after administration of sub-Tenon and retrobulbar anaesthesia. (2) Intraocular pressure comparison of sub-Tenon, retrobulbar and peribulbar administration. Setting: Seventy-eight routine scheduled local anaesthetic administrations for cataract surgery at Moorfields Eye Hospital. Patients: Twenty-eight patients had sub-Tenon administration, 23 retrobulbar injection and 27 peribulbar administration. Main Outcome Measures: Volume administered and change in intraocular pressure. Results: The mean volume used was 3.2 ml for sub-Tenon, 3.6 ml for retrobulbar and 6.4 ml for peribulbar administration. After sub-Tenon delivery there was mean rise in intraocular pressure of 0.9 mmHg and after retrobulbar injection a mean rise of 1.4 mmHg. These rises did not reach statistical significance. Peribulbar injection involved a larger mean volume of administration than the sub-Tenon or retrobulbar techniques, with a mean rise of intraocular pressure of 4.9 mmHg, which is statistically significant ( P Conclusions: Retrobulbar and sub-Tenon administration have only a marginal effect upon intraocular pressure for small volumes (3–4 ml) and sub-Tenon administration of this volume load appears to be safe with regard to intraocular pressure. Where a significant volume of local anaesthetic agent is administered, as with peribulbar injection, this is likely to be associated with a significant rise in intraocular pressure and consideration should be given to use of a pressure lowering device.

Pseudophakic malignant glaucoma: Nd:YAG capsulotomy as a primary treatment

Abstract: Malignant glaucoma is one of the most serious but rare complications of anterior segment surgery. It is best known following trabeculectomy but has been reported following a wide variety of anterior segment procedures including extracapsular cataract extraction with posterior chamber lens implantation. It is notoriously refractory to medical treatment alone and surgical intervention has had only limited success. An additional treatment option in pseudophakic eyes is that of peripheral Nd:YAG posterior capsulotomy, which is minimally invasive and can re-establish forward flow of posteriorly misdirected aqueous through into the drainage angle of the anterior chamber. We report our experience of seven cases of malignant glaucoma in pseudophakic eyes and of the successful use of Nd:YAG posterior capsulotomy in re-establishing pressure control in five of these eyes, thereby obviating the need for acute surgical intervention.

The frequency and clinical significance of bone involvement in outer canthus dermoid cysts.

Abstract: Periorbital dermoid cysts should be removed because they commonly leak their irritant contents into the surrounding tissues. The underlying bone may, however, be involved in patients with dermoid cysts at the outer canthus. Computed tomography studies of 70 patients (43 men and 27 women, aged 30 months to 63 years, mean 29 years) with proved dermoid cysts of this type were reviewed. The lesion was always unilateral; 34 were on the left. The bone of the lateral wall and superotemporal angle of the orbit showed the following abnormalities, often in combination: pressure erosion in 61 cases and an otherwise abnormal shape, probably developmental, in 55; the dermoid cyst entered a tunnel or canal through the lateral wall in 24; a blind pit or crater in 15; and a cleft in 20; many patients also showed abnormal bone texture. These findings are extremely important for planning adequate surgery, and indicate that bony involvement is much more frequent than previously appreciated.

Excimer laser photorefractive keratectomy for myopia: 12 month follow-up.

Abstract: A prospective study of excimer laser photorefractive keratectomy was performed with the aim of correcting a range of myopic errors between −1.00 and −10.00 dioptres. Corneal healing was monitored through the first post-operative year by serial assessments of refraction, contrast sensitivity, corneal haze, pachymetry and keratometry. Eighty-one patients were recruited for the study. At 12 months 81% were within ± 1.00 dioptre of desired emmetropia and with unaided vision of 6/12. Contrast sensitivity was found by Pelli–Robson assessment to be reduced throughout the 12 months and regression analysis predicted recovery by 2 years. At 12 months, however, only 15% of patients were found to have lost a single line of best corrected Snellen acuity. Predictability of results was found to be greatest for initial errors less than −4.00 dioptres. No serious complications were observed during the follow-up period, but refraction had not stabilised in all cases and patients remain under review.

Disease and risks associated with contact lenses.

Abstract: Contact lens (CL) wear, as an alternative to spectacles for the treatment oflow refractive errors, is widespread in developed countries. It results in a number of inevitable ocular changes which, with the exception of endothelial polymegethism, are short term and recover after lens wear has ceased; these effects are seldom of functional significance. The risks of lens wear result from both these inevitable ocular responses and the additional potential that exists for developing a CL associated disease. These risks must be set against the optical and cosmetic advantages and convenience resulting from lens use. This risk:benefit ratio should be considered by all contact lens users and practitioners before embarking on lens wear. Contact lens associated disease, as opposed to the inevitable consequences of wear, develops in only some contact lens users. It includes minor ocular adverse reactions such as corneal neovascularisation, representing a suboptimal ocular response to the stress of lens wear, as well as severe complications such as microbial keratitis. This review summarises the effect of these on the community, the features distinguishing CL related disorders from other external eye diseases, their classification, and epidemiology.

Association of familial Duane anomaly and urogenital abnormalities with a bisatellited marker derived from chromosome 22.

Abstract: We report a spectrum of defects that were found in an 18-year-old girl who presented for investigation of primary amenorrhea. The patient was found to have Duane anomaly, left renal agenesis, absent uterus, bilateral sen-sorineural deafness, and bilateral preauricular skin tags and sinuses. Investigation of her family showed that her brother also had Duane anomaly, right renal agenesis, sensorineural deafness, and preauricular skin tags. Cytogenetic analysis, including in situ hybridisation of peripheral blood lymphocytes, demonstrated a supernumerary bisatellited marker chromosome derived from the region of chromosome 22pter-q11 in the affected individuals. Our findings indicate that a gene or genes located in the region of chromosome 22pter-q11 may be associated with the Duane anomaly and the development of the urogenital tract. © 1993 Wiley-Liss, Inc.