Interpretation of uniocular and binocular trials of glaucoma medications: an observational case series

<p>Abstract</p> <p>Background</p> <p>To predict the effectiveness of topical glaucoma medications based on initial uniocular and binocular treatment. To test a traditional hypothesis that effectiveness following a uniocular trial is associated with the change in IOP in the initially treated eye minus the change in the initially untreated eye. To determine whether uniocular or binocular treatment trials are superior.</p> <p>Methods</p> <p>Based on a review of medical records, we identified 168 instances in 154 patients with bilateral primary open angle glaucoma of initial uniocular use of a topical glaucoma medication with well-documented intraocular pressure (IOP) readings at baseline (IOP_A), during the trial (IOP_B), and at follow-up (IOP_C). Abstracted data included demographic data, IOP, and medication use. Predictors of the IOP following the trial (IOP_C) in each eye were identified by multivariable linear regression. In 70 cases, the predictive ability of initial uniocular and binocular treatment could be directly compared.</p> <p>Results</p> <p>In a multivariable analysis, the follow-up pressure in the initially treated eye (IOP_1C) was directly correlated with treated eye IOP during initial uniocular use (IOP_1B, p < 0.001). In a multivariable analysis, the follow-up pressure in the initially untreated eye (IOP_2C) was directly correlated with its baseline IOP_2A(p < 0.001), and also tended to be associated with treated IOP_1B(p = 0.07). The multivariable regression coefficient (b) for the IOP change in the initially untreated eye was generally not close to the value of -1 expected by the classic teaching (for eye 1, b = 0.04, p = 0.35; for eye 2, b = 0.07, p = 0.50). In 70 cases, the uniocular and binocular trials predicted a similar fraction of the variance in follow-up IOP_1C(r²= 0.56 and 0.57, respectively) and IOP_2C(r²= 0.39 and 0.38, respectively).</p> <p>Conclusion</p> <p>1) For uniocular trials, the IOP change in the untreated eye should not be subtracted from that in the treated eye. 2) Uniocular and binocular trials have similar predictive value when interpreted correctly. Either may be selected based on clinical circumstances.</p

Evaluation of a combined index of optic nerve structure and function for glaucoma diagnosis

<p>Abstract</p> <p>Background</p> <p>The definitive diagnosis of glaucoma is currently based on congruent damage to both optic nerve structure and function. Given widespread quantitative assessment of both structure (imaging) and function (automated perimetry) in glaucoma, it should be possible to combine these quantitative data to diagnose disease. We have therefore defined and tested a new approach to glaucoma diagnosis by combining imaging and visual field data, using the anatomical organization of retinal ganglion cells.</p> <p>Methods</p> <p>Data from 1499 eyes of glaucoma suspects and 895 eyes with glaucoma were identified at a single glaucoma center. Each underwent Heidelberg Retinal Tomograph (HRT) imaging and standard automated perimetry. A new measure combining these two tests, the structure function index (SFI), was defined in 3 steps: 1) calculate the probability that each visual field point is abnormal, 2) calculate the probability of abnormality for each of the six HRT optic disc sectors, and 3) combine those probabilities with the probability that a field point and disc sector are linked by ganglion cell anatomy. The SFI was compared to the HRT and visual field using receiver operating characteristic (ROC) analysis.</p> <p>Results</p> <p>The SFI produced an area under the ROC curve (0.78) that was similar to that for both visual field mean deviation (0.78) and pattern standard deviation (0.80) and larger than that for a normalized measure of HRT rim area (0.66). The cases classified as glaucoma by the various tests were significantly non-overlapping. Based on the distribution of test values in the population with mild disease, the SFI may be better able to stratify this group while still clearly identifying those with severe disease.</p> <p>Conclusions</p> <p>The SFI reflects the traditional clinical diagnosis of glaucoma by combining optic nerve structure and function. In doing so, it identifies a different subset of patients than either visual field testing or optic nerve head imaging alone. Analysis of prospective data will allow us to determine whether the combined index of structure and function can provide an improved standard for glaucoma diagnosis.</p

Prevalence of optic disc haemorrhages in an elderly UK Caucasian population and possible association with reticular pseudodrusen—the Bridlington Eye Assessment Project (BEAP): a cross-sectional study (2002–2006)

Aims: To determine disc haemorrhages (DH) prevalence in an elderly UK population-the Bridlington Eye Assessment Project (BEAP).Methods: Thirty-degree (30°) fundus photographs (3549 participants ≥65 years) were graded for DH/macula changes. Glaucoma evaluation included Goldmann tonometry, 26-point suprathreshold visual-fields and mydriatic slit-lamp assessment for glaucomatous optic neuropathy.Results: 3548 participants with photographs in at least one eye. DH were present in 53 subjects (1.49%), increasing from 1.17% (65-69-year age-group) to 2.19% (80-84-year age53 group), p=0.06. DH was found in 9/96 (9.38%) right eyes (RE) with open angle glaucoma (OAG). Two of twelve RE (16.67%) with normal tension glaucoma (NTG) had DH. Prevalence in eyes without glaucoma was lower (32/3452, [0.93%]). Reticular pseudodrusen (RPD) occurred in 170/3212 (5.29%) subjects without DH, and 8/131 subjects (6.11%) with OAG. Twenty (20) eyes had normal tension glaucoma (NTG), 2 of whom had RPD (10%) (p=0.264). Within a logistic regression model, DH was associated with glaucoma (OR 10.2, 95% CI 5.32 - 19.72) and increasing age (OR 1.05, 95% CI 1.00-1.10, p=0.03). DH was associated with RPD (p=0.05) with univariate analysis but this was not statistically significant in the final adjusted model. There was no significant association with gender, diabetes mellitus (DM), hypertension treatment or AMD grade.Conclusion: DH prevalence is 1.5% in those over 65 years old and significantly associated with glaucoma and increasing age. There appears to be increased RPD prevalence in eyes with DH and NTG with age acting as a confounding factor. Larger studies are required to fully assess the relationship and investigate a possible shared aetiology of choroidal ischaemia