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Biomedical subjects

S Beatty

Publications and source records attributed to S Beatty.

At least 37 records · Page 2Linked to original sources
PubMed2000

Macular pigment optical density measurement: a novel compact instrument.

A compact device to derive the optical density of human macular pigment (MP) using heterochromatic flicker photometry is described. The validity of the system is assessed by measuring the optical density spectra of MP in 12 healthy subjects and comparing this with well-established previously published values. The mean spectral absorbance characteristics of MP across subjects corresponds well with accepted values. As reported in other studies, our measurements show a wide variation of MP optical densities between individuals. In our technique within-subject variability is low; standard deviations are between 0.025 and 0.15 in most cases. The overall optical density of MP ranged from 0.08 to 0.84 with a mean of 0.496 and standard deviation of 0.257 at 460 nm. The stimulus size was 0.95 degrees. The unique feature of the technique is that it allows free viewing (not Maxwellian View) of the stimulus, it can be conducted easily and quickly and does not need frequent re-calibration.

Humans↗
PubMed2000

Optic atrophy in association with cobalamin C (cblC) disease.

PURPOSE: To report the association of optic atrophy with cobalamin C (cblC) disease. METHODS: Descriptive case reports on three patients, two of whom were siblings. RESULTS: All three patients with cblC disease exhibited bilateral optic atrophy with decreased visual acuity. Of the two siblings, the younger sister had received cobalamin supplements from birth and the mother had been given cobalamin supplements prenatally. CONCLUSION: These three cases confirm the association of optic atrophy with cblC disease. Early treatment with cobalamin supplements does not appear to prevent the development of optic atrophy.

Age of Onset↗
PubMed2000

The changing pattern of cytomegalovirus retinitis in human immunodeficiency virus disease.

There have been profound changes in the pattern of cytomegalovirus (CMV) retinitis over the last two decades. The epidemiology and behaviour of CMV retinitis has been significantly altered by Acquired Immune Deficiency Syndrome (AIDS). It was uncommon prior to the AIDS epidemic, but soon became the most common retinal infection in AIDS patients. In the past several years, highly active anti-retroviral treatment (HAART) has achieved a dramatic improvement in the prognosis for patients infected with human immunodeficiency virus (HIV). As a result, HIV patients are living longer and have a reduced risk of CMV retinitis. Some patients with CMV retinitis who respond to HAART develop a transient symptomatic vitritis while others undergo no reactivation of their retinitis despite having no specific anti-CMV therapy. This pattern is likely to undergo further change as the treatment of HIV and CMV disease continues to improve.

AIDS-Related Opportunistic Infections↗
PubMed1999

Non-organic visual loss.

Visual complaints without a physical basis are not uncommon presentations to the general physician, the neurologist, or the ophthalmologist. These alleged visual disturbances may be psychogenic or feigned. The diagnosis is made when all possible contributory pathology of the visual system is excluded, and reassurance remains the cornerstone of management.

Blindness↗
PubMed1999

Cytomegalovirus retinitis in patients with acquired immune deficiency syndrome.

Cytomegalovirus (CMV) retinitis is the most common intra-ocular infection in patients with acquired immune deficiency syndrome (AIDS), and a leading cause of AIDS-related morbidity. Untreated CMV retinitis in AIDS patients is a progressive and potentially blinding disorder. The diagnosis of CMV retinitis is a clinical one and it is important for physicians to be familiar with the clinical features of the disease. Ophthalmic screening of AIDS sufferers should be undertaken at regular intervals, and this is dictated, in part, by the patient's CD4+ T-lymphocyte (CD4) counts. CMV retinitis may be treated with systemic ganciclovir, foscarnet or cidofovir, or with local (intravitreal) therpy. CMV-related retinal detachment is treated surgically. In some patients with quiescent CMV retinitis receiving highly active anti-retroviral therapy, anti-CMV maintenance therapy may be discontinued in favour of close ophthalmologic observation and CD4 count monitoring.

Anti-HIV Agents↗
PubMed1998

Necrotizing sclerokeratitis following uncomplicated cataract surgery.

PURPOSE: To report a case of surgically induced necrotising sclerokeratitis (SINS) with imminent uveal prolapse following uncomplicated cataract surgery. METHODS: Case report. RESULTS: The causative agent was found to be a subtarsal abscess and the condition responded to drainage of the localised infection and a course of topical antibiotics. CONCLUSION: This report represents the first account of postoperative scleral necrosis arising from a subconjunctival abscess, and illustrates the importance of identifying all aetiopathogenic factors in cases of postsurgical necrotizing scleritis.

Abscess↗
PubMed1998

Evaluation of optic disc cupping using high-resolution ocular ultrasound.

BACKGROUND/PURPOSE: The new Biovision B-Scan Probe has greater resolution than its predecessors because of its posteriorly placed focus (25 mm inside the eye) and the consequent reduction in size of the sound field. We investigated the accuracy, reproducibility and test-retest variability of two-dimensional optic cup measurements using this new-generation B-scanner. METHODS: One randomly selected eye of 20 patients underwent five repeated measurements of vertical (VOCD) and horizontal optic cup diameters (HOCD), and optic cup depth, using confocal scanning laser tomography (Heidelberg Retinal Tomograph) and high-resolution ultrasound (Biovision, Chiron Vision, UK) on two separate occasions. There was one operator per instrument who was masked to all clinical data and previous measurements. Accuracy of ultrasound readings was quantified by comparing the results with those of Heidelberg Retinal Tomography (HRT). RESULTS: The 95% confidence interval for the bias of echographic vertical and horizontal cup diameter measurements was -95 +/- 48 microns and -19 +/- 72 microns respectively, and -87 +/- 328 microns for cup depth readings. The indices of reproducibility (mean coefficient of repeatability +/- SD) were: VOCD: 177 +/- 105 microns [B-scan] 209 +/- 100 microns [HRT]; HOCD: 179 +/- 61 microns [B-scan], 205 +/- 101 microns [HRT]; cup depth: 206 +/- 63 microns [B-scan], 204 +/- 124 microns [HRT]. Ninety-five per cent limits of agreements between initial and retest values for ultrasound were 18 +/- 136 microns [VOCD], 2 +/- 144 microns [HOCD] and 4 +/- 156 microns [cup depth], compared with 1 +/- 104 microns [VOCD], 20 +/- 102 microns [HOCD] and 3 +/- 168 microns [cup depth] for scanning laser tomography. CONCLUSION: The results demonstrate that measurements of optic cup diameter and depth using ultrasound correlate strongly with corresponding HRT readings. These echographic measurements are reproducible, and not subject to clinically meaningful test-retest variability. This technique of measuring two-dimensional cup parameters does not require expensive specialist equipment and has many potential clinical applications which are discussed.

Aged↗
PubMed1998

Correlation between the orbital and intraocular portions of the optic nerve in glaucomatous and ocular hypertensive eyes.

BACKGROUND/PURPOSE: It has recently been reported that the retrobulbar optic nerve diameter (OND) and cross-sectional area (ONCSA) are reduced in glaucoma. This study was performed to investigate the correlation between the orbital and intraocular portions of the optic nerve. METHODS: One eye of 20 volunteers (16 glaucoma subjects, 4 ocular hypertension subjects) underwent optic disc analysis using Heidelberg retinal tomography, and echographic measurements of the retrobulbar optic nerve. RESULTS: The male-to-female ratio was 6.5:3.5, and the mean age of our sample (+/- SD) was 62.25 +/- 13.7 years. Orbital optic nerve diameter and cross-sectional area correlated significantly and positively with the neuroretinal rim area (Spearman's rank correlation coefficient; OND: rs = 0.488, p = 0.0336; ONCSA: rs = 0.619, p = 0.0079), but not with any other topographical disc data. The retrobulbar optic nerve cross-sectional area-to-disc area ratio (ONCSA/D) was found to have a significant negative correlation with the cup area/disc area ratio (simple regression analysis; r = -3.948, p = 0.046), and a statistically demonstrable positive correlation with the neuroretinal rim area/disc area ratio (r = 0.451, p = 0.046). CONCLUSION: The results of this study indicate that orbital optic nerve dimensions are a reflection of the neuroretinal rim area of the optic disc. Echographic measurements of the retrobulbar nerve may be additive to the traditional triad of raised intraocular pressure, field defects and glaucomatous optic neuropathy that suggests a diagnosis of glaucoma.

Adult↗
PubMed1998

Surgical excision of subfoveal neovascular membranes.

BACKGROUND: Subfoveal choroidal neovascular membranes (CNV) are a cause of significant visual impairment. Laser treatment of such lesions results in visual loss. Surgical excision of CNV may allow stabilisation or improvement of vision. A series of results of surgical excision are presented. METHODS: The records for 43 eyes of 40 consecutive patients undergoing surgical excision of CNV not associated with age-related macular degeneration (AMD) were reviewed retrospectively. Statistical analyses of the relationship between pre-operative factors and post-operative visual results were made. Improvement or worsening of visual acuity was defined as a change of more than 2 lines of Snellen acuity. RESULTS: In 79.1% of patients visual acuity was improved or unchanged following surgery, and in 20.9% there was a reduction of Snellen acuity. There was no statistically significant association between visual outcome and age, gender, duration of visual symptoms, cause of CNV, presence of subretinal haemorrhage, elevation of retina by subretinal fluid, prior laser surgery, or the presence of pre-operative or intraoperative subretinal haemorrhage. There was a possible association between the non-use of gas tamponade and an increased chance of reduced vision. Visual loss was more likely in those eyes with good pre-operative visual acuity. Recurrence of CNV was noted in 10 (23%) eyes; repeat surgery was not associated with a worse visual outcome. CONCLUSIONS: Surgical excision of CNV not related to AMD is a promising technique. More meaningful assessment of visual function in these patients will allow refinement of case selection.

Adolescent↗
PubMed1998

Acute intraoperative suprachoroidal haemorrhage in ocular surgery.

PURPOSE/BACKGROUND: Acute intraoperative suprachoroidal haemorrhage (AISH) is the most sight-threatening complication of ocular surgery. We investigated the visual outcomes following this intraoperative event, patient characteristics that may predispose to it and the clinical features that may be of prognostic significance. METHODS: The records of 45 cases of AISH collected from ophthalmic centres in the United Kingdom, Republic of Ireland and Switzerland were reviewed. Two satisfactory controls in terms of operative procedure, surgeon, age (+/- 5 years) and gender were found for each of 33 of our cases. Systemic and ocular characteristics were compared for cases and controls, and the visual results of all cases of AISH are analysed. RESULTS: Cases and controls differed only in terms of axial length and pre-operative intraocular pressure, both of which were significantly greater for eyes that experienced an AISH (p < 0.05). Ten eyes (22.2%) achieved a final Snellen acuity of 6/12 or better. Statistically significant associations with a final acuity of counting fingers or worse included spontaneous nuclear expression (p = 0.02), retinal detachment (p < 0.0001), four-quadrant suprachoroidal haemorrhage (p = 0.007) and vision of perception of light or worse at the first dressing (p = 0.0001). Four of the 6 eyes that experienced an AISH during phacoemulsification surgery had a visual outcome of 6/12 or better, and this was significantly greater than for cases involving extracapsular cataract surgery (p = 0.004). CONCLUSION: The results indicate that longer axial length and higher pre-operative intraocular pressure are associated with increased risk of AISH. Poor visual results are more likely following spontaneous nuclear expression, retinal detachment, four-quadrant suprachoroidal haemorrhage or vision of perception of light or worse at the first dressing. The results also suggest that AISH complicating a phacoemulsification procedure has a more favourable visual prognosis than AISH that occurs during extracapsular cataract surgery.

Acute Disease↗
PubMed1998

The role of ophthalmic triage and the nurse practitioner in an eye-dedicated casualty department.

PURPOSE: To evaluate the appropriateness of triage decisions in a busy ophthalmic casualty department and to assess the diagnostic and management skills of eye-dedicated nurse practitioners. METHODS: Three hundred and one consecutive patients attending the Birmingham and Midland Eye Centre (BMEC) accident and emergency (A&E) department over a 2 week period were included in this prospective study. Patients were categorised in terms of urgency in concordance with strict guidelines, and the agreement between the final diagnosis and this system of prioritisation was then investigated. To evaluate nurse practitioner (NP) skills, all patients seen and managed by a NP were also assessed by the most senior doctor in casualty at the time in a masked fashion. Waiting times and a breakdown of waiting times were also calculated. RESULTS: Upon establishment of a diagnosis, triage category allocation was found to be appropriate in all 301 cases. Fifty patients (16.67%) were seen by the NP. Of these the supervising doctor concurred with the NP diagnosis in all cases and with the proposed management in 96% of cases. The mean waiting time (+/- SD) was 83.43 +/- 45.84 min, with a range of 5-335 min. The delay before being attended to was greater for less urgent cases as categorised by the triage system. CONCLUSION: This study confirms the high standard of diagnostic and management skills of the ophthalmic NP and indicates that the triage system of patient prioritisation is accurate. Waiting times in the A&E department remain unacceptable and ways of addressing this include improved ophthalmic training of general practitioners, diverting a greater proportion of non-acute cases to the primary care clinic and expanding the role of the NP.

Adolescent↗
PubMed1998

Echographic measurements of the retrobulbar optic nerve in normal and glaucomatous eyes.

AIM: A study was designed to investigate whether measurements of the optic nerve diameter (OND) and cross sectional area (ONCSA), as measured by B-scan ultrasonography, are altered in glaucoma. The reproducibility and test-retest variability of echographic estimates of retrobulbar optic nerve dimensions was also tested. METHODS: One eye of 49 glaucoma patients and 90 control subjects underwent five repeated echographic measurements of the maximal interpial diameter and cross sectional area of the orbital optic nerve on two separate occasions. All measurements were taken by one experienced ultrasonographer. RESULTS: Mean optic nerve diameter (SD) for the control group was 2.86 (0.46) mm, and was independent of height (multiple regression analysis: p = 0.21), axial length (p = 0.74), spherical equivalent (p = 0.97), sex (ANOVA: p = 0.36), or race (p = 0.14), but was inversely related to age (p = 0.01). Reproducibility of OND readings in control subjects was 0.149 mm (coefficient of repeatability). Test-retest variability of interpial diameter was -0.02 (0.29) mm. Mean interpial diameter of the optic nerve was significantly smaller among glaucomatous eyes (2.58 (0.501) mm) than controls (Mann-Whitney U test: p < 0.0001). Glaucomatous optic nerves also had a significantly smaller cross sectional area (6.68 (2.58) mm2) than those of healthy volunteers (8.25 (1.67) mm2) (p = 0.004). CONCLUSION: Echographic measurements of the orbital optic nerve are highly reproducible and not subject to clinically meaningful test-retest variability. Optic nerve interpial diameter and cross sectional area are reduced in glaucomatous eyes, reflecting nerve fibre loss. This technique may be useful in distinguishing between normal and glaucomatous eyes where optic disc morphometry is inconclusive or impossible as a result of opaque media.

Aged↗
PubMed1998

Trabeculectomy augmented with mitomycin C application under the scleral flap.

AIM: The authors investigated the safety and intraocular pressure (IOP) lowering effectiveness of trabeculectomy augmented with mitomycin C application beneath the scleral flap, and assessed the influence of preoperative risk factors on the surgical outcome. METHODS: A retrospective study of 72 consecutive high risk eyes undergoing trabeculectomy with adjunctive mitomycin C (0.2 mg/ml) applied under the scleral flap for 5 minutes was performed. Each eye was ascribed a score based on the number of preoperative risk factors, and categorised into one of three risk factor groups. Success was described as unqualified where IOP was < or = 21 mm Hg without medication and qualified where antiglaucomatous therapy was required to maintain it at such a level. A life table analysis of IOP control was calculated. RESULTS: The mean IOP (SD) fell from a preoperative level of 28.4 (6.9) to a level of 16.63 (8.06) mm Hg at the last follow up (paired Student's t test: p < 0.0001). Fifty two eyes (72%) were classed as unqualified successes. The survival rates did not differ significantly between different risk factor groups (log rank test: chi 2 = 0.967, p > 0.1). The incidence of postoperative complications compared favourably with reports of mitomycin C application between Tenon's capsule and the undissected scleral bed. CONCLUSION: The results illustrate that mitomycin C applied beneath the scleral flap during trabeculectomy in high risk eyes is associated with a success rate comparable to other modes of application. The incidence of potentially serious complications such as conjunctival wound leak and prolonged hypotony was lower than previously published data reporting sub-Tenon's administration of mitomycin C. The number and nature of preoperative risk factors do not appear to influence the surgical outcome. A possible mechanism of action is proposed.

Adult↗