-
Driving Simulation as a Performance-based Test of Visual Impairment in Glaucoma
The fundamental goal of glaucoma management is to prevent patients from developing visual impairments sufficient to produce disability in their daily lives and impair their quality of life. Ultimately, patients are interested in how their vision will impact their ability to perform daily activities, such as driving. Although technologic advancements such as automated perimetry and devices for optic nerve imaging have resulted in great improvement in our ability to quantify structural and functional damage in glaucoma, the impact on vision-related quality of life of some of the information acquired from these tests remain elusive. In contrast, performance-based measures may be better correlated to traditional measures of vision health and, more importantly, they provide a more direct measure of disability. Driving simulators can be used as a performance-based test for evaluation of functional impairment in glaucoma. Their use can potentially help in the evaluation of driving safety and performance of diseased subjects and provide insight into the different mechanisms involved in causing driving impairment in this disease. The ability to do this in an experimentally controlled and standardized setting enables testing of a much larger number of hypotheses compared with on-road evaluations. Besides evaluating driver fitness, simulators could also potentially be used as a sophisticated test to evaluate cognitive impairment in the context of an everyday task (driving) that has not been available through traditional neuropsychologic assessment.
-
Evaluation of Macular Thickness and Peripapillary Retinal Nerve Fiber Layer Thickness for Detection of Early Glaucoma Using Spectral Domain Optical Coherence Tomography
Purpose: To evaluate the diagnostic ability of macular parameters and peripapillary retinal nerve fiber layer (RNFL) parameters for early glaucoma using spectral domain optical coherence tomography (SD-OCT).
Materials and methods: One eye from 32 early glaucoma patients (including preperimetric glaucoma) and 32 normal participants underwent macular scans and peripapillary RNFL scans with SD-OCT 3 times on the same day. The discrimination power of each parameter to detect early glaucoma was determined by areas under receiver operating characteristics curve (AROC) and sensitivity at fixed specificity. Correlation of OCT data with visual field defects was evaluated by linear regression analysis. Reproducibility was also evaluated.
Results: Significant differences between early glaucoma and normal participants were found for all parameters except fovea in macular scans and in the superior and inferior quadrants, at 12, 3, 6, 7, 11 o'clock, and average RNFL thickness in RNFL scans. The best parameters based on AROC and sensitivity at a specificity of >90% were temporal outer macula thickness (AROC, 0.79; sensitivity, 63%) in macular parameters and inferior quadrant (AROC, 0.82; sensitivity, 53%) in RNFL parameters. The highest correlation with mean deviation was found in inferior inner macular volume (r=0.50, P<0.001). The mean intraclass correlation coefficient was 0.96 in macular scans and 0.84 in RNFL scans. Test-retest variability ranged from 2.3 to 10.1 ?m in macular thickness, 0 to 0.06 mm3 in macular volume, and 5.8 to 18.9 ?m in RNFL thickness.
Conclusion: For the diagnosis of early glaucoma by SD-OCT, macular parameters had high discriminating power and high reproducibility comparable with peripapillary RNFL parameters.
-
Digital Ocular Massage for Hypertensive Phase After Ahmed Valve Surgery
Purpose: To examine the role of ocular massage during the hypertensive phase after Ahmed valve surgery
Methods: Nonrandomized prospective study.
Results: Eighteeen patients with intraocular pressure (IOP) above target 1 to 8 weeks after Ahmed glaucoma drainage device surgery underwent digital ocular massage. The mean IOP 1 hour after massage was 4.3 mm Hg lower than before massage (18.8%, P=0.0008). We used a 20% reduction in IOP at 1-hour postmassage to differentiate responders from nonresponders and by this definition 50% responded to ocular massage. One patient (5.6%) responded well but was unable to perform massage at home. The remaining 8 patients (44.4%) performed regular digital massage and the 20% drop in IOP was maintained at the 2-week, 6-week, and 6-month review, although by 6 months 50% required glaucoma drops to achieve target IOP. There were no massage-associated complications in this series.
Conclusions: Digital ocular massage has a useful role to play in the management of the hypertensive phase after Ahmed glaucoma drainage device surgery. In this series 50% of patients achieved a 20% drop in IOP with massage.
(C) 2010 Lippincott Williams & Wilkins, Inc.
-
Corneal Thickness Measurements in Normal-tension Glaucoma Workups: Is It Worth the Effort?
Purpose: To correlate central corneal thickness (CCT) and intraocular pressure (IOP) with disease severity in normal-tension glaucoma (NTG) patients.
Methods: We conducted a retrospective review of all patients diagnosed with NTG in our institution between 2002 and 2006. NTG was diagnosed according to the glaucomatous visual fields loss, glaucomatous optic disc cupping, and an IOP <22 mm Hg on diurnal curve measurements. Mean CCT and IOP values before and after treatment were also evaluated. Patients were divided into 3 groups according to advanced glaucoma intervention score (mild, moderate, and severe visual field defects).
Results: A total of 33 females and 35 males with bilateral NTG were enrolled. The mean follow-up was 4.6 years. CCT was inversely correlated with glaucoma severity. CCT was normal in both eyes in mild disease, thin in the right eye (RE) and normal in the left eye (LE) in moderate disease, and low in both eyes in severe disease. Initial bilateral mean maximal IOP was similar at all disease stages and became lower after treatment in parallel to disease severity: 13.44, 12.22, and 11.63 mm Hg in the RE and 13.29, 12.60, and 12.32 mm Hg in the LE, respectively. There was no statistical difference in disease severity between the RE and LE.
Conclusions: CCT correlated with disease severity: the more advanced the disease, the thinner the cornea. Initial maximal IOP did not predict disease severity, but it was lower in the more severe cases after treatment, possibly representing a more aggressive treatment protocol.
(C) 2010 Lippincott Williams & Wilkins, Inc.
-
Goniotomy for Juvenile Open-Angle Glaucoma
Purpose: To report the surgical results of goniotomy surgery for patients with acquired juvenile open-angle glaucoma (JOAG).
Patients and Methods: The medical records of 10 patients with bilateral acquired JOAG were reviewed to learn the results of goniotomy for their glaucoma. Twenty goniotomy procedures were performed for 17 eyes. Sex, ethnicity, family history, refraction, preoperative gonioscopic findings, surgical outcome, age at initial goniotomy, duration of postoperative observation, preoperative and postoperative intraocular pressures (IOP), and glaucoma medication used were reviewed. Complete success was defined as an IOP <=21 mm Hg, qualified success as IOP <=21 mm Hg with use of glaucoma medications, and failure as IOP >21 mm Hg despite medical therapy. The surgical technique used to perform the goniotomy procedures was reviewed and the absence of significant complications noted.
Results: Overall surgical success was achieved in 77% (13 out of 17) of the eyes. Average IOP for complete success (9 eyes) was 14.7+/-2.1 mm Hg (range: 12 to 18 mm Hg), qualified success (4 eyes) 16.5+/-2.4 mm Hg (range: 14 to 19 mm Hg), and failure (4 eyes) 33.5+/-5.7 mm Hg (range: 30 to 42 mm Hg). The mean age at surgery was 16.3+/-8.1 years (range: 7.3 to 32 y). Mean follow-up interval was 7.8+/-6.2 years (range: 0.1 to 16.3 y). Gonioscopy demonstrated normal appearing filtration angles in all eyes. No significant surgical complications occurred. Mean refractive error was -3.3+/-2.8 (range: 0.0 to -7.8). Sixty percent of patients possessed a family history of JOAG.
Conclusions: Goniotomy is a potentially effective initial surgical treatment of JOAG. Goniotomy for JOAG can be successfully performed using a standard goniotomy technique.
(C) 2010 Lippincott Williams & Wilkins, Inc.
|
