Technical Note: A comparison of central and peripheral intraocular pressure using rebound tonometry

Purpose: To compare central and peripheral intraocular pressure (IOP) readings obtained with rebound tonometry.Methods: Intraocular pressure was measured on the right eye of 153 patients (65 males, 88 females), aged from 21 to 85 years (mean +/- S.D., 55.5 +/- 15.2 years) with the ICare rebound tonometer at centre, and 2 mm from the limbus (in the nasal and temporal regions along the 0-180O corneal meridian).Results: Intraocular pressure values obtained with the ICare were 14.9 +/- 2.8; 14.1 +/- 2.5 and 14.5 +/- 2.7 mmHg at centre, nasal and temporal corneal locations, respectively. On average, nasal and temporal IOP readings were 0.75 and 0.37 mmHg lower than the central reading (p 0.05, respectively). A highly significant correlation was found between central and peripheral measurements in nasal (r(2) = 0.905; p < 0.001) and temporal (r(2) = 0.879; p < 0.001) regions along the horizontal meridian. Almost 80% of patients presented nasal IOP values within +/- 1 mmHg of the central value.Conclusions: Intraocular pressure values measured with the ICare (R) rebound tonometer on the nasal corneal region is slightly lower on average and highly correlated with IOP values recorded at corneal centre. Both nasal and temporal readings are in good agreement with central IOP, and could be used to obtain a reliable estimate of rebound IOP in corneas where central readings cannot be taken.- (undefined

Short-term safety and efficacy of Preserflo™ Microshunt in glaucoma patients: a multicentre retrospective cohort study

Background/aims: To evaluate 1-year success rates and safety profile of Preserflo™ Microshunt in glaucoma patients. Methods: Retrospective multicentre cohort study of 100 consecutive eyes (91 patients) from four tertiary-referral glaucoma centres. Four intraocular pressure (IOP) criteria were defined: A: IOP ≤ 21 mmHg+IOP reduction ≥20% from baseline; B: IOP ≤ 18 mmHg+IOP reduction ≥20%; C: IOP ≤ 15 mmHg+IOP reduction ≥25%; D: IOP≤12 mmHg+IOP reduction ≥30%. Success was defined as qualified or complete based on whether reached with or without medication. Primary outcome was success according to the above criteria. Secondary outcomes included: IOP, best-corrected visual acuity (BCVA), medication use, complications, postoperative interventions, and failure-associated factors. Results: Qualified and complete success rates (95% CI) at 12 months were 74%(66–83%) and 58%(49–69%) for criterion A, 72%(63–82%) and 57%(48–68%) for B, 52%(43–63%) and 47%(38–58%) for C, 29%(21–40%) and 26%(19–36%) for D. Overall median (interquartile range (IQR)) preoperative IOP decreased from 21.5(19–28) mmHg to 13(11–16) mmHg at 12 months. BCVA was not significantly different up to 12 months (p = 0.79). Preoperative median (IQR) number of medications decreased from 3 (2–3) to 0 (0–1) at 12 months. Twelve eyes underwent needling, five surgical revision and one device removal due to corneal oedema. There were no hypotony-related complications. Non-Caucasian ethnicity was the only risk factor consistently associated with increased failure. Conclusions: Preserflo™ Microshunt is a viable surgical option in glaucoma patients, with reasonable short-term success rates, decreased medications use, excellent safety profile, smooth postoperative care, and rapid learning curve. Success rates for the most stringent IOP cutoffs were modest, indicating that it may not be the optimal surgery when very low target IOP is required

Corneal Segmentation Analysis Increases Glaucoma Diagnostic Ability of Optic Nerve Head Examination, Heidelberg Retina Tomograph’s Moorfield’s Regression Analysis, and Glaucoma Probability Score

Purpose. To study whether a corneal thickness segmentation model, consisting in a central circular zone of 1 mm radius centered at the corneal apex (zone I) and five concentric rings of 1 mm width (moving outwards: zones II to VI), could boost the diagnostic accuracy of Heidelberg Retina Tomograph’s (HRT’s) MRA and GPS. Material and Methods. Cross-sectional study. 121 healthy volunteers and 125 patients with primary open-angle glaucoma. Six binary multivariate logistic regression models were constructed (MOD-A1, MOD-A2, MOD-B1, MOD-B2, MOD-C1, and MOD-C2). The dependent variable was the presence of glaucoma. In MOD-A1, the predictor was the result (presence of glaucoma) of the analysis of the stereophotography of the optic nerve head (ONH). In MOD-B1 and MOD-C1, the predictor was the result of the MRA and GPS, respectively. In MOD-B2 and MOD-C2, the predictors were the same along with corneal variables: central, overall, and zones I to VI thicknesses. This scheme was reproduced for model MOD-A2 (stereophotography along with corneal variables). Models were compared using the area under the receiver operator characteristic curve (AUC). Results. MOD-A1-AUC: 0.771; MOD-A2-AUC: 0.88; MOD-B1-AUC: 0.736; MOD-B2-AUC: 0.845; MOD-C1-AUC: 0.712; MOD-C2-AUC: 0.838. Conclusion. Corneal thickness variables enhance ONH assessment and HRT’s MRA and GPS diagnostic capacity

Comparison of the ICare (R) rebound tonometer with the Goldmann applanation tonometer by experienced and inexperienced tonometrists

© 2008 The Royal College of OphthalmologistsPurpose To assess the agreement between ICare® rebound tonometer and Goldmann applanation tonometer in the hands of experienced and inexperienced tonometrists. Patients and methods Two tonometrists, experienced with both Goldmann applanation tonometry (GAT) and ICare® Tonometry (ICT) measured intraocular pressure (IOP), in a masked fashion, in 100 patients. In another series of 58 patients, ICT was performed by an inexperienced tonometrist and GAT by an experienced tonometrist. Results In approximately 80% of patients, the difference in IOP between GAT and ICT was 2 mmHg in group 1 and 3 mmHg in group 2. The 95% limits of agreement were - 4.0–4.4 mmHg in group 1 and - 6.0–5.0 mmHg in group 2. Conclusion ICT compares reasonably with GAT, in both experienced and inexperienced hands. Its ease of use, portability, and sterility make it an attractive tonometer. Its degree of accuracy in inexperienced hands would make it a useful instrument for health care workers with limited ophthalmic experienceL M Abraham, N C R Epasinghe, D Selva and R Casso