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Biomedical subjects

D J Spalton

Publications and source records attributed to D J Spalton.

At least 19 recordsLinked to original sources
PubMed1992

Quantification of the ocular response to treatment in posterior uveitis.

Twenty patients with posterior uveitis were studied by anterior segment fluorophotometry to determine whether there was a relationship between the degree of breakdown of the blood-aqueous barrier and the clinical recovery of posterior uveitis. In individual eyes the degree of breakdown and recovery of the blood-aqueous barrier (as measured by changes in the anterior chamber fluorescein concentration) followed the resolution and relapse of disease making it possible to quantify the ocular response to treatment.

Adult↗
PubMed1992

Horner's syndrome: an electron microscopic study of a human iris.

Electron microscopy was performed on the irides of a man with a history of a long standing Horner's syndrome which resulted in iris heterochromia. Comparison of his normal brown iris with the depigmented blue iris showed depletion of anterior border cells and absence of sympathetic nerve fibres. Stromal melanocyte numbers were also diminished but melanosome numbers within the residual cells were not significantly different. Postnatal maintenance of stromal and anterior border zone pigmentation, derived from the neural crest, would appear to be dependent on an intact sympathetic nerve supply in contrast to the iris pigment epithelium which remains normally unaffected in Horner's syndrome.

Adrenergic Fibers↗
PubMed1992

Continued breakdown of the blood aqueous barrier following cataract surgery.

Following routine extracapsular cataract and posterior chamber implant surgery, recovery of the blood aqueous barrier (BAB) was quantified by sequential anterior chamber fluorophotometry. This was correlated with surgical details and postoperative findings to ascertain those factors which were related to excessive damage of the BAB immediately after surgery and to failure to recover a normal BAB by 3 months postoperatively. A cohort of 84 patients was followed. In the early postoperative period excessive levels of damage to the BAB were related to iris damage (p < 0.01) and diabetes mellitus (p < 0.01). By 3 months, 79% of the eyes had recovered normal BABs and 21% (18 eyes) had persisting excessive fluorescence which correlated with an abnormal pupil shape (p < 0.02) and the development of posterior synechiae (p < 0.001).

Adult↗
PubMed1992

The effects of subconjunctival betamethasone on the blood aqueous barrier following cataract surgery: a double-blind randomised prospective study.

The aim of this double-blind randomised prospective study was to assess the effect of subconjunctival Betnesol (betamethasone sodium phosphate 0.1%) on the recovery of the blood aqueous barrier (BAB) following cataract surgery in uncomplicated eyes. Twenty patients [10 male, mean age 71.4 (SD 12.7) years] admitted for routine cataract surgery were randomised into two groups. All patients recruited into the study were free of other ocular disease and were not taking any anti-inflammatory medication. Group A received a subconjunctival injection of cefuroxime (125 mg) alone while group B received a subconjunctival injection of both cefuroxime and Betnesol. All surgery was performed by a single surgeon using a standardised surgical technique and all patients received the same postoperative medication. The Kowa laser flare cell meter was used to measure aqueous flare and cells preoperatively and on the first, second, and seventh postoperative day, and at 1 and 3 months following surgery. The code was broken only after all patients had been followed-up for 3 months postoperatively. There was no significant difference between the two groups in aqueous flare and cells at any of the postoperative visits. In this study we were unable to demonstrate any beneficial effect of subconjunctival betamethasone on damage to and recovery of the BAB following cataract surgery in the uncomplicated eye.

Adult↗
PubMed1992

Neuroenteric cyst of the optic nerve: case report with immunohistochemical study.

A 36 year old man developed slowly progressive unilateral visual loss due to a cystic lesion of the intraorbital optic nerve. Pathologically the lesion was an epithelium lined cyst entirely within the atrophic nerve. The cyst lining consisted of columnar epithelium partly pseudostratified and ciliated with evidence of mucin secretion, and was immunoactive for cytokeratin but not glial fibrillary acidic protein. This lesion is considered to be similar to neuroenteric cysts that have been reported elsewhere in the nervous system, and the immunocytochemical results are consistent with a heterotopia derived from the primitive ectoderm of the stomatodeum.

Adult↗
PubMed1992

Mucolipidosis type IV. Presentation of a mild variant.

The authors report a 16-year-old girl with mucolipidosis type IV. She was referred because of deteriorating vision over the past three years. Corneal clouding with the appearance of cornea verticillata and retinal dystrophy were the main ophthalmological findings. Except for clumsiness no psychomotor retardation was present. Ultrastructural analysis of a conjunctival biopsy and cultured fibroblasts suggested a diagnosis of mucolipidosis type IV which was confirmed by biochemical studies. This patient represents the mildest described presentation of mucolipidosis type IV.

Adolescent↗
PubMed1992

Correlations between laser flare measurements and anterior chamber protein concentrations.

The laser flare cell meter quantifies anterior chamber (AC) protein (flare) by measuring light scattering of a helium-neon laser beam in the AC. The relationship between photon count and protein concentration both in vitro and in vivo was assessed. The reproducibility of the in vitro photon count measurements was 7.3%. There was a significant linear relationship between photon count and the concentration of both albumin (r = 1.0, P = 0.0001) and immunoglobulin G (IgG, r = 0.99, P = 0.0001) in vitro, but the linear-regression formulas were different with greater light scattering by IgG than by albumin at the same concentration. Laser flare measurements were done on 22 patients (12 normal eyes, 5 eyes with Fuchs' heterochromic cyclitis, and 5 uveitic eyes) before cataract surgery. Aqueous humor obtained from these patients by paracentesis was analyzed for total protein, albumin, and IgG concentration. There was a significant linear relationship (r = 0.88, P = 0.0001) between the laser flare value (range, 5.8-107.8 photons/msec) and the total aqueous protein concentration (range, 14-388 mg/dl). Use of an in vitro albumin calibration curve to convert photon count into protein concentration was found to overestimate the actual protein concentration. This overestimation was slight in normal eyes and increased with increased blood-aqueous barrier breakdown. The use of such a calibration curve therefore is not appropriate in studies on diseased eyes. The authors recommended that laser flare results be expressed in either photons per milliseconds or converted into an equivalent protein concentration using a calibration curve based on actual AC protein measurements.

Aged↗
PubMed1991

Long-term endothelial cell loss and breakdown of the blood-aqueous barrier in cataract surgery.

Progressive endothelial cell loss and endothelial cell loss induced at the time of surgery occurs in all eyes with rigid anterior chamber intraocular lenses (IOLs). Eyes with surgical tuck or late ovaling of the pupil following surgery have greater yearly rates of cell loss than eyes that have no complications. This progressive loss may be related to chronic uveitis from iris chafing by the implant or to direct mechanical damage to the corneal endothelium. We have demonstrated that fluorophotometry shows chronic damage to the blood-aqueous barrier in all eyes with rigid anterior chamber IOLs, but this does not correlate with the degree of endothelial cell loss. Our results suggest there is damage to the blood-aqueous barrier and to the corneal endothelium, but the damage to the latter influences progressive endothelial cell loss.

Aged↗
PubMed1991

Recovery of the blood-aqueous barrier after cataract surgery.

Following extracapsular cataract and posterior chamber implant surgery the sequential recovery of the blood-aqueous barrier was measured by anterior segment fluorophotometry. Postoperatively 49 (69.0%) out of 71 eyes (71 patients) had recovered at a uniform rate, re-establishing a normal blood-aqueous barrier by the end of the three-month study. In these eyes recovery of the blood-aqueous barrier was unaffected by the use of preoperative indomethacin, the surgeon, the type of section, or the type of fixation of the implant. In eyes recovering normally after cataract surgery the rate of recovery of the blood-aqueous barrier can be expressed by a in the equation a = (y-b)/x, in which y is the logarithm of the anterior chamber fluorescence, x is the time after surgery, and b is a constant for each patient which is the anterior chamber fluorescence measured immediately after surgery. This normal rate of recovery provides a baseline from which to assess surgical technique or postoperative medication.

Adult↗
PubMed1991

Acute retinal necrosis syndrome.

Acute retinal necrosis (ARN) is a rare syndrome with characteristic fundal appearances which can have devastating effects on vision. We present six cases (nine eyes) seen in the Medical Eye Unit of St Thomas's Hospital over the past six years and discuss the clinical features, aetiology, and management. Our findings support the present consensus that the condition is caused by varicella zoster virus (VZV) or herpes simplex virus (HSV). One of our patients, who was atypical in having common variable hypogammaglobulinaemia, had suffered a widespread zosteriform rash immediately prior to the onset of ARN, while another had suffered a herpes simplex uveomeningoencephalitis. All cases had characteristic confluent peripheral retinal necrosis, and three of the nine eyes developed retinal detachment. Retinal arteritis was a prominent and helpful diagnostic feature in one case. From combining all reports to date of this rare condition it is possible to conclude that ARN is unilateral in 65% of cases.

Adult↗
PubMed1991

Measurement of aqueous cells and flare in normal eyes.

(abstractThe Kowa laser cell flare meter has been recently introduced to quantify the assessment of aqueous cells and flare in vivo by measurement of light scattering from a low power HeNe beam. Computer analysis of this scattered light can distinguish cells (expressed as cell count) from protein (expressed as photon count/ms), and in-vitro work with albumin solutions has shown that the photon count/ms is linearly related to protein concentration. This study of 106 normal eyes (53 subjects) assesses the accuracy and sensitivity of the instrument and the factors affecting the interpretation of its results. Using in-vitro solutions of human albumin we found a highly significant linear correlation (r = 1, p = 0.0001) between photon count and protein concentration. The results show that the instrument has a photon count/ms reproducibility of 8.26% and that there is a within-subject variability in photon count/ms (aqueous flare) of 12.2% in normal eyes. No significant difference in photon count/ms (aqueous flare) was found to exist between right and left eyes (p greater than 0.4), between sexes (p greater than 0.5), or between irides of different colour (p greater than 0.8). There was also no statistically significant variation in photon counts/ms with time of day over the period of measurement (1000-1900 h) (p = 0.4). There was, however, an increase in photon count/ms with age (r = 0.57, p less than 0.001) and a decrease with pupillary dilatation at both 30 and 60 minutes after instillation of tropicamide 1% (p less than 0.05). An occasional cell was found in only 10.4% of normal eyes, and there was no significant increase in the cell counts on mydriasis (p>0.05). These findings indicate that the Kowa laser flare meter is an accurate and sensitive instrument with potential application in the investigation of blood-aqueous barrier.

Adolescent↗
PubMed1991

Ptosis caused by pachydermoperiostosis.

Pachydermoperiostosis is a rare inherited disorder which presents with finger clubbing, facial enlargement, and periostitis. A case is described in which surgery for ptosis was performed and the differential diagnosis of the condition is discussed. The histological and ultrastructural appearances of the eyelids show sebaceous gland hyperplasia and excessive deposition of mucin in the dermis and would suggest that pachydermoperiostosis may be an example of a cutaneous mucinosis.

Adult↗
PubMed1990

Decentration of the posterior chamber lens implant: the effect of optic size on the incidence of visual aberrations.

Intraocular lens implant components such as dialling holes can cause disabling symptoms when decentration of the implant places these components in the pupil. In order to investigate the importance of optic size in this context, we studied two groups of consecutive patients who had undergone cataract surgery: one group had received an implant with a 6 mm diameter optic, and the other an implant with a 7 mm diameter optic. We found that there was a significantly higher incidence of implant components such as dialling holes in the pupil in the 6 mm group when compared to the 7 mm group. The incidence of symptoms such as monocular diplopia and glare was marginally but not significantly higher in the 6 mm group. To minimise the risks of symptoms related to dialling holes in the pupil we recommend an implant design that has a large optical clear zone of at least 6 mm.

Aged↗
PubMed1990

Microvascular study of the retrolaminar optic nerve in man: the possible significance in anterior ischaemic optic neuropathy.

The morphology of the circle of Haller and Zinn and its variations were examined using methyl-methacrylate microvascular corrosion casting of human orbits obtained at post-mortem. It was found to be an elliptical microvascular anastomosis formed by branches of the medial and lateral para-optic short posterior ciliary arteries. The ellipse was divided into superior and inferior parts by the entry points of these branches into the eye, providing an altitudinal blood supply to the retrolaminar optic nerve. Morphological variations in terms of form, position and branches existed between subjects and between eyes from the same subject. The clinical implications of an elliptical 'circle' of Haller and Zinn providing an altitudinal blood supply to the retrolaminar optic nerve are relevant to the pathogenesis of altitudinal visual field defects in anterior ischaemic optic neuropathy.

Adult↗
PubMed1990

Intraocular tuberculosis.

Twelve patients with a diagnosis of intraocular tuberculosis are described. Nine patients presented with florid ischaemic retinal vasculitis and a marked tendency to neovascularisation. Two patients developed choroidal tubercles; iris nodules were observed in association with anterior uveitis in the remaining patient. The methods of diagnosis, management and possible mechanisms of pathogenesis of these different clinical presentations are discussed.

Adult↗
PubMed1990

Central retinal vein occlusion in people aged 40 years or less: a review of 17 patients.

Seventeen patients with central retinal vein occlusion aged 40 or under were reviewed. Ocular involvement was characteristically unilateral, with moderate degrees of retinal haemorrhage, little retinal ischaemia, and a tendency to optic disc swelling. Visual prognosis was good. Follow-up showed that most patients have good general health and no involvement of the fellow eye. There was little evidence to support an inflammatory aetiology or underlying vascular disease in most of the patients. An alternative explanation for the development of CRVO in young patients might be a congenital anomaly of the central retinal vein.

Adolescent↗