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Biomedical subjects

Stephen A Vernon

Publications and source records attributed to Stephen A Vernon.

12 recordsLinked to original sources
PubMed2006

Single perioperative triamcinolone injection versus standard postoperative steroid drops after uneventful phacoemulsification surgery: Randomized controlled trial.

PURPOSE: To evaluate the safety and efficacy of a single perioperative sub-Tenon's injection of triamcinolone following cataract surgery and its effect on the incidence of early pseudophakic cystoid macular edema (CME). SETTING: Ophthalmology Department, Queen's Medical Centre University Hospital, Nottingham. United Kingdom. METHODS: This prospective randomized controlled trial included 54 eyes (54 patients) having routine cataract surgery. Twenty-seven eyes received the conventional postoperative care with steroid drops (drops group), whereas the other 27 were given a perioperative sub-Tenon's injection of triamcinolone (injection group); 10 of these received 20 mg, and the remaining 17 eyes had 30 mg triamcinolone. All patients were evaluated preoperatively and at days 1, 8, 30, and 90. The outcome measures evaluated were logMAR best corrected visual acuity (BCVA), anterior chamber flare (Kowa-500 flare meter), intraocular pressure, and slitlamp biomicroscopy. Oral fluorescein angiograms were performed at 30 and 90 days to detect angiographic CME. RESULTS: The mean logMAR BCVA improved from a baseline of 0.38 +/- 0.38 (SD) and 0.44 +/- 0.26 to 0.02 +/- 0.14 and 0.0 +/- 0.07 at 90 days in the steroid drops and injection groups, respectively. (P = .59). The mean flare increased from a baseline of 8.9 +/- 3.2 photons/ms and 8.3 +/- 3.7 photons/ms in the steroid drops and injection groups, respectively, to a maximum of +/-14.1 photons/ms and 25.8 +/- 7.5 photons/ms at day 8. Mean flare decreased to 15.8 +/- 9.7 photons/ms and 13.8 +/- 10.1 photons/ms at 30 days (P = .48, difference between groups) and 10.4 +/- 3.6 photons/ms and 9.8 +/- 3.1 photons/ms at 90 days, respectively, in the 2 groups. Subanalysis revealed lowest peak flare (17.9 +/- 7.9 photons/ms) at 8 days in the group that received 30 mg triamcinolone. CONCLUSIONS: A single sub-Tenon's injection of 30 mg triamcinolone seem to be safe and effective as a route of steroid delivery after uneventful phacoemulsification surgery. Larger numbers in patients at high risk are required to assess its effectiveness in reducing the risk for pseudophakic CME.

Administration, Topical↗
PubMed2006

Specificity of the Heidelberg Retina Tomograph's diagnostic algorithms in a normal elderly population: the Bridlington Eye Assessment Project.

PURPOSE: To determine the specificity of the Moorfields regression analysis (MRA) and R. Burk (RB) and F. S. Mikelberg (FSM) linear discriminant functions (LDFs) in classifying the optic discs of normal elderly patients imaged with the Heidelberg Retina Tomograph. DESIGN: Cross-sectional study. PARTICIPANTS: Optic nerve head analysis of 459 eyes of 459 normal elderly patients was performed by 2 operators. All patients were consecutive in a cohort screened for eye disease. Normals were defined as having a normal visual field (VF) on automated suprathreshold screening, normal intraocular pressure, and normal visual acuity. MAIN OUTCOME MEASURES: Specificity of the optic nerve head classification by MRA and the RB and FSM LDFs. RESULTS: Subjects' mean age (262 female, 197 male) was 72.6 years. Males were found to have significantly larger cups than females. Eighty-three percent, 11.3%, and 5.7% of discs were classed as within normal limits, borderline, and outside normal limits by MRA. Percentages of optic discs classified as outside normal limits in the smallest and largest quartiles for disc size were 0.9% and 14.9%. The association of disc size with the classification of outside normal limits was significant in males only. Agreement in MRA classification between 2 investigators separately placing the optic disc contour was moderate (Cohen's kappa = 0.54, P<0.001). The RB and FSM LDFs classified 6.8% and 11.8% of discs as diseased. The RB LDF was significantly more likely to return a diagnosis of disease in larger discs, though only in males. The FSM LDF tended to the same drop in specificity, although not significantly. CONCLUSIONS: Using the MRA and RB/FSM LDFs, specificity fell dramatically with increasing disc size, particularly in males. This may reflect the finding of significantly larger cups in males than in females in the normal elderly population. This divergence was not predicted by these diagnostic functions, which were developed on samples of younger subjects.

Aged↗
PubMed2006

Successful treatment of invasive cavernous sinus aspergillosis with oral itraconazole monotherapy.

An 83-year-old woman receiving long-term prednisolone treatment presented with a right optic neuropathy and right third, fourth, fifth, and sixth cranial nerve palsies secondary to sino-orbital aspergillosis with cavernous sinus involvement. Because the patient refused conventional treatment, she was given a two-year course of oral itraconazole 200 mg/day, leading to a complete imaging resolution of the lesion. Three years after completing treatment, there is no clinical or imaging evidence of disease recurrence. Visual and ocular motor function did not recover, but ptosis and proptosis improved. We believe this to be the first documented case of successful treatment of such a lesion with oral itraconazole monotherapy.

Administration, Oral↗
PubMed2006

Diode laser cycloablation in adult glaucoma: long-term results of a standard protocol and review of current literature.

BACKGROUND: To study the long-term efficacy and safety of diode laser cycloablation under a standard protocol in refractory glaucoma. METHODS: A retrospective study involving 42 eyes (39 patients), observed for 36-84 (mean 65.7) months after cycloablation involving 14 burns of 2-W power and 2-s duration, over 270 degrees of the ciliary body. RESULTS: By final review, mean intraocular pressure (IOP) had dropped by 50.3% from 31.4 +/- 8.8 mmHg before treatment to 15.6 +/- 6.3 mmHg (P < 0.0001). Thirty-seven of the 42 eyes (88.1%) achieved IOP < 22 mmHg. Thirty-five of the 42 eyes (83.3%) eyes achieved IOP reduction > or = 30% from baseline levels. The mean number of antiglaucoma medications per eye dropped from 2.55 +/- 0.83 to 1.71 +/- 1.44 (P = 0.0004). The percentage of eyes requiring oral acetazolamide dropped from 92.9% to 11.9% (P < 0.0001). About 59.6% of eyes required multiple treatment sessions (mean 2.17). Twenty-seven (64.3%) eyes suffered deterioration, 11 (26.2%) maintained stability and 4 (9.5%) exhibited improvement of visual acuity. No relationship between the number of treatment sessions and visual outcome was evident. CONCLUSIONS: This conservative repeatable protocol affords delivery of the minimum dose of photocoagulation necessary to achieve a safe, long-term ocular hypotensive response, while minimizing the risk of serious adverse effects, and is valuable in the difficult treatment of refractory glaucoma.

Acetazolamide↗
PubMed2005

Laser scanning tomography of the optic nerve head in a normal elderly population: the Bridlington eye assessment project.

PURPOSE: To assess optic nerve head topographic parameters using the Heidelberg Retina Tomograph (HRT) II (Heidelberg Engineering GmbH, Dossenheim, Germany) in a normal elderly population. METHODS: Optic nerve head analysis of 918 eyes of 459 normal elderly patients was performed. All patients were consecutive in a cohort screened for eye disease. Normal subjects were defined with a normal visual field on automated suprathreshold screening, intraocular pressure less than 22 mmHg, and minimum corrected visual acuity of 6/12. All optic discs were contoured by two investigators and the mean parameters analyzed. The effects of age, sex, and disc size were assessed. RESULTS: Subjects' (262 women and 197 men) mean age was 72.6 +/- 5.1 (SD) years (range, 65.5-89.3). Mean +/- SD global disc area, cup/disc area ratio, and neuroretinal rim area were 1.98 +/- 0.36 mm2, 0.22 +/- 0.14, and 1.52 +/- 0.31 mm2, respectively. Disc area did not differ significantly based on eye side or sex. The women were found to have a significantly larger rim volume, mean retinal nerve fiber layer (RNFL) thickness, and cross-sectional area than the men and tended to have smaller cup areas/volumes and cup/disc area ratios. Most tomography parameters were found to be significantly influenced by disc size. CONCLUSIONS: To the authors' knowledge, this is the first large study of optic nerve head parameters in the elderly normal population using the HRT II. This age range is particularly relevant to glaucoma detection and pertinent to discriminant analyses separating normal subjects from glaucoma in screening for the disease. Given the systematic differences between the parameters in men and women, reference ranges should be quoted by sex.

Aged↗
PubMed2005

Asymmetry in optic disc morphometry as measured by heidelberg retina tomography in a normal elderly population: the Bridlington Eye Assessment Project.

PURPOSE: To define the normal range of asymmetry in optic disc parameters measured by the Heidelberg Retina Tomograph (HRT II; Heidelberg Engineering GmbH, Dossenheim, Germany) in a normal elderly population. METHODS: Optic disc analysis of 918 eyes of 459 normal elderly patients was performed. All patients were consecutive in a cohort screened for eye disease. Normality was defined with a normal visual field on automated suprathreshold screening, intraocular pressure less than 22 mm Hg, and minimum corrected visual acuity of 6/12. Asymmetry measures were calculated by subtracting the values of the smaller disc from those of the larger disc. RESULTS: Subjects' mean age (262 female and 197 male) was 72.6 years (range, 65.5-89.3). There was no significant difference in disc area or rim area between the right and left eyes. Neither rim-to-disc area ratio asymmetry nor rim measurement asymmetries were significantly affected by age or sex. Rim-to-disc area ratio asymmetry was much less affected by the increasing difference in disc size than was absolute rim asymmetry. The 2.5th and 97.5th percentile limits of normality for the rim-to-disc area ratio asymmetry in the global and temporal-inferior analyses were -0.212 and 0.154, and -0.331 and 0.261, respectively. CONCLUSIONS: The normal range of parameter asymmetry in an age group relevant to glaucoma may be useful in the discrimination of normal from early glaucoma. Asymmetry analysis may improve discriminatory ability by reducing parameter variability based on disc size. The rim-to-disc area ratio asymmetry measure is likely to be the most useful parameter in describing normality with consistency.

Aged↗
PubMed2003

Clinical agreement among glaucoma experts in the detection of glaucomatous changes of the optic disk using simultaneous stereoscopic photographs.

PURPOSE: To evaluate the clinical agreement in the detection of optic disk changes in patients with glaucoma using simultaneous stereophotographs. DESIGN: Masked-observer variability study. METHODS: Ten glaucoma specialists examined pairs of simultaneous stereophotographs of glaucomatous and control optic disks to determine whether there were changes compatible with progression of glaucomatous damage. RESULTS: Intraobserver agreement had a kappa value ranging from 0.55 to 0.78. Interobserver agreement among the glaucoma specialists had a kappa value ranging from 0.34 to 0.68. CONCLUSIONS: Clinical examination of stereophotographs to detect optic disk changes in glaucoma patients has limitations associated with suboptimal reproducibility.

Diagnostic Techniques, Ophthalmological↗
PubMed2003

Repeatability of ocular blood flow pneumotonometry.

PURPOSE: To establish the repeatability of ocular blood flow (OBF) pneumotonometry and its agreement with Goldmann tonometry. DESIGN: Instrument evaluation study. PARTICIPANTS: Ten female healthcare professionals. METHODS: Intraocular pressure (IOP) was measured by one experienced ophthalmologist in both eyes of 10 healthy female subjects on 10 different occasions at the same time of day. The two methods were performed by alternate allocation, and laterality was chosen by random order. Repeatability coefficients and agreement plots were calculated by using the Bland-Altman method. MAIN OUTCOME MEASURES: Intraocular pressure repeatability coefficients. RESULTS: Mean IOPs were 15.6 mmHg (right) and 15.1 mmHg (left) by OBF pneumotonometry and 12.6 mmHg (right) and 12.4 mmHg (left) by Goldmann tonometry (P < 0.001). The repeatability coefficients were 7.06 (right) and 7.66 (left) for the OBF pneumotonometer and 4.81 (right) and 3.87 (left) for the Goldmann tonometer. With regard to agreement, the OBF pneumotonometer read significantly higher than did the Goldmann tonometer. The mean bias for the right eye was 2.92 (95% limits of agreement, -4.37 to 10.20), and for the left eye it was 2.68 (95% limits of agreement, -3.93 to 9.28). CONCLUSIONS: In our group of healthy females, the repeatability of the OBF pneumotonometer was worse than that of the Goldmann tonometer. This casts doubt on the value of the OBF pneumotonometer as a tool for measuring IOP. The agreement plots indicate that the OBF pneumotonometer may produce significant numbers of false-positive results in screening programs.

Adult↗
PubMed2003

An overview of the eye in diabetes.

The three papers in this symposium are based on presentations to an RSM meeting on the Diabetic Eye, held on 9 April 2003. The matter is particularly topical because the National Service Framework for Diabetes calls for a high-quality retinal screening programme. After a review of the various ophthalmic conditions likely to be encountered in diabetic patients (A Negi, S A Vernon) we proceed to the most important, diabetic retinopathy, with a discussion of screening methods (D M Squirrell, J F Talbot) and an account of laser treatments (J G F Dowler). Colour versions of the clinical photographs are available online [www.jrsm.org]. Publication was coordinated by Professor Susan Lightman, of Moorfields Eye Hospital, London, UK.

Adult↗
PubMed2002

Agreement in assessing optic discs with a digital stereoscopic optic disc camera (Discam) and Heidelberg retina tomograph.

AIMS: To assess the intraobserver agreement, interobserver agreement, and the agreement between a digital stereo optic disc camera (Discam) and Heidelberg retina tomograph (HRT) in measuring area cup-disc ratio (ACDR) and radial cup-disc ratio (RCDR) by two observers. METHODS: The optic discs of 78 eyes of 39 people (17 cases of primary open angle glaucoma, eight normal tension glaucoma, two ocular hypertension, and 12 normal subjects) were imaged with Discam and HRT. Two observers independently drew the disc margins on the HRT mean topography images and the disc and cup margins on the Discam images. ACDR and the RCDR at various angles were measured with the two systems. Intraobserver agreement, interobserver agreement, and the agreement between the two systems were assessed by 95% tolerance limit of changes (TC) and intraclass correlation coefficient (ICC). RESULTS: Eight eyes were excluded due to poor image quality (six Discam and two HRT). 70 eyes were analysed. The intraobserver ACDR agreement was almost perfect in both systems (ICCs = 0.97 and 0.92, and TCs = 11.0% and 15.1% in HRT and Discam respectively). The interobserver ACDR agreement was almost perfect in HRT (ICC = 0.97) and substantial in Discam (ICC = 0.79), (TCs = 10.5% and 24.5% respectively). The ACDR agreement between the two systems was substantial in observer A (ICC = 0.67) and moderate in observer B (ICC = 0.53), (TCs = 24.8% and 46.7% respectively). The HRT measured the ACDR significantly larger than the Discam (p <0.001), and the differences were significantly larger in the glaucomatous group (p <0.001). RCDR agreement between the two systems was fair to substantial in observer A (ICC = 0.36 to 0.74) and slight to moderate in observer B (ICC = 0.12 to 0.45). Both observers achieved the best RCDR agreement between the two systems at the inferior optic disc position. CONCLUSION: There is almost perfect intraobserver agreement in each system. The interobserver agreement was better with the HRT than the Discam. There was substantial variation in ACDR and RCDR agreement between the two systems measured by the two observers. The variation in ACDR and RCDR measurements between the two systems may be too large for interchangeable use in a clinical setting.

Adult↗