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Objective-To test the validity and generalizability of the Ocular Hypertension Treatment Study (OHTS) prediction model for the development of primary open angle glaucoma (POAG) in a large independent sample of untreated ocular hypertensive individuals. To develop a quantitative calculator to estimate the 5-year risk that an individual with ocular hypertension will develop POAG.Design-A prediction model was developed from the observation group of the OHTS and then tested on the placebo group of the European Glaucoma Prevention Study (EGPS) using a z-statistic to compare hazard ratios, a c-statistic for discrimination and a calibration chi-square for systematic over/under estimation of predicted risk. The two study samples were pooled to increase precision and generalizability of a 5-year predictive model for developing POAG.Participants-The OHTS observation group (n=819, 6.6 years median follow-up) and the EGPS placebo group (n=500, 4.8 years median follow-up).Testing-Data were collected on demographic characteristics, medical history, ocular examination visual fields and optic disc photographs.Main Outcome Measures-Development of reproducible visual field abnormality or optic disc progression as determined by masked readers and attributed to POAG by a masked endpoint committee.Results-The same predictors for the development of POAG were independently identified in both the OHTS observation group and the EGPS placebo group -baseline age, intraocular pressure (IOP), central corneal thickness, vertical cup/disc ratio, and Humphrey visual field pattern standard deviation. The pooled multivariate model for the development of POAG had good discrimination (cstatistic 0.74) and accurate estimation of POAG risk (calibration chi-square 7.05). Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptOphthalmology. Author manuscript; available in PMC 2008 January 1. Conclusions-The OHTS prediction model was validated in the EGPS placebo group. A calculator to estimate the 5-year risk of developing POAG, based on the pooled OHTS-EGPS predictive model, has high precision and will be useful to clinicians and patients in deciding the frequency of tests and examinations during follow-up and the advisability of initiating preventive treatment.

Purpose: To assess reproducibility of central corneal thickness (CCT) measurement by means of ultrasonic pachymetry. Methods: Fifty one volunteers underwent three sessions of CCT measurements, each consisting of three CCT measurements, performed by each of three different observers. Intraand interobserver reproducibility was calculated by means of intraclass correlation coefficient (ICC). The expected range of variability between two independent evaluations was calculated using scatter plots of each test-retest difference against their mean. The standard deviation of the mean differences in the test-retest scores was used to describe the differences in the score spread. Results: The ICC ranges of the intra-and interobserver evaluations were 0.95-0.97 and 0.89-0.95 respectively; the expected variability was (¡1% and (¡ 2% respectively (95% confidence interval). Conclusions: The measurement of CCT by means of ultrasonic pachymetry is highly reproducible.T he measurement of central corneal thickness (CCT) is an important step in ophthalmic evaluations preceding kerato-refractive surgery.1 It is also an increasingly important procedure in the evaluation of patients with ocular hypertension (OHT) or glaucoma. CCT can be clinically assessed by means of optical or ultrasonic pachymetry, 2 and optical coherence tomography. 21Only a few studies have attempted to evaluate the variability of ultrasonic pachymetry: their results show a good degree of reproducibility, although most of them involved small sample sizes or were designed to compare ultrasonic pachymetry with other methods of measuring CCT. 22-29The aim of this study is to evaluate the variability of ultrasonic pachymeter in the clinical setting and to provide a quantitative estimate of expected CCT measurements repeated by the same or different operators. MATERIALS AND METHODSOne eye was randomly chosen for each of 51 volunteers aged 49-82 years (31 healthy individuals, 16 patients with OHT, and four patients with primary open angle glaucoma).Individuals with previous corneal surgery, previous or current corneal disease, and contact lens wear were excluded from the study.Ultrasonic pachymetry was performed with an undilated pupil using an ''Altair'' Ultrasonic Pachymeter (Optikon 2000, Rome, Italy) whose probe tip is approximately 1 mm in diameter.The pachymeter was calibrated at the beginning of each session. After the instillation of a topical anaesthetic (oxibuprocain 0.4%), the probe was placed perpendicularly on the central cornea. This was confirmed by an audible beep produced by the instrument.Three well trained operators (EA, MG, GM) independently measured the CCT of each eye in a random sequence within 3-4 minutes of each other in order to rule out the influence of possible diurnal variations in CCT. [30][31][32][33] In order to reduce the possibility of ocular surface drying, 27 one drop of artificial tear (Dacriosol, Alcon, Fort Worth, TX, USA) was instilled 30 seconds before each measurement. Each measurement was recorded by an assistant. The observe...

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Current management of glaucoma entails the medical, laser, or surgical reduction of intraocular pressure (IOP) to a predetermined level of target IOP, which is commensurate with either stability or delayed progression of visual loss. In the published literature, the hypothesis is often made that IOP control implies a single IOP measurement over time. Although the follow-up of glaucoma patients with single IOP measurements is quick and convenient, such measurements often do not adequately reflect the untreated IOP characteristics, or indeed the quality of treated IOP control during the 24-h cycle. Since glaucoma is a 24-h disease and the damaging effect of elevated IOP is continuous, it is logical that we should aim to understand the efficacy of all treatment options throughout the 24-h period. This article first reviews the concept and value of diurnal and 24-h IOP monitoring. It then critically evaluates selected available evidence on the 24-h efficacy of medical, laser and surgical therapy options. During the past decade several controlled trials have significantly enhanced our understanding on the 24-h efficacy of all glaucoma therapy options. Nevertheless, more long-term evidence is needed to better evaluate the 24-h efficacy of glaucoma therapy and the precise impact of IOP characteristics on glaucomatous progression and visual prognosis.Electronic supplementary materialThe online version of this article (doi:10.1007/s12325-016-0302-0) contains supplementary material, which is available to authorized users.