Marcelo Ayala

Corneal hysteresis in normal subjects and in patients with primary open-angle glaucoma and pseudoexfoliation glaucoma.

Purpose: To identify differences in corneal hysteresis (CH) between primary open-angle glaucoma (POAG), pseudoexfoliative glaucoma patients (PXSG) and a healthy control group. Methods: In this retrospective study, CH was measured with the Ocular Response Analyzer. 90 subjects were evaluated, 30 subjects in each group. One eye per subject was analyzed. Results: In normal eyes, POAG and PXSG, CH was 9.8 ± 1.6, 9.0 ± 1.9 and 8.0 ± 1.5 mm Hg, respectively. CH was significantly lower in PXSG patients than in POAG (p = 0.042) and normal patients (p = 0.0001), but no significance was found between the POAG and the normal group (p = 0.23). Conclusion: CH differs in the different groups and might be considered in glaucoma evaluation. Further studies with larger sample sizes are needed.

Inflammation assessment after selective laser trabeculoplasty (SLT) treatment

Purpose:  Selective laser trabeculoplasty (SLT) appears to be a safe and effective method to lower intraocular pressure (IOP). The exact mechanism of action for reducing IOP and inflammation levels is not known.

The Effect of Exposure Time on Maximum Acceptable Dose for Avoidance of Ultraviolet Radiation-Induced Cataract

The effect of exposure time on maximum acceptable dose (MAD) for avoidance of ultraviolet radiation B (UVRB)-induced cataract was investigated. Sprague-Dawley rats were divided into 5 exposure time groups: 7.5, 15, 30, 60, and 120 min. Each exposure time group was divided into 5 dose subgroups: 0, 1, 2, 4, and 8 kJ/m2. The rats were unilaterally exposed to UVR around 300 nm. One week after the exposure, macroscopic structure was recorded and lens forward light scattering was measured. MAD for avoidance of UVRB-induced cataract was estimated based on the dose-response function. MAD for avoidance of UVRB-induced cataract for 7.5, 15, 30, 60, and 120 min exposures was estimated to be 2.0, 1.4, 1.9, 1.8 and 2.2 kJ/m2, respectively. In the exposure time domain 7.5–120 min, MAD for avoidance of UVRB-induced cataract depends on exposure time.

Reversal of reciprocity failure for UVR-induced cataract with vitamin E.

Purpose: The authors have previously described that the photochemical reciprocity law does not apply for ultraviolet radiation (UVR)-induced cataract. The aim of this study was to elucidate if failure of the reciprocity reverses with vitamin E (α-tocopherol) administration. Methods: Altogether, 80 rats were divided into one group fed α-tocopherol and one control group. For each group, half of rats were exposed to UVR for 5 min and the remaining rats for 15 min. Results: Lenses exposed to UVR for 5 min showed no difference in light scattering between α-tocopherol-treated and untreated groups. Lenses exposed to UVR for 15 min showed significant difference in light scattering between α-tocopherol-treated and untreated groups. Conclusions: Failure in exposure time-intensity reciprocity for UVR-induced cataract with exposures shorter than 30 min may be due to consumption of antioxidants in the lens.

Comparison of the monocular Humphrey visual field and the binocular Humphrey esterman visual field test for driver licensing in glaucoma subjects in Sweden

BackgroundThe purpose of this study was to compare the monocular Humphrey Visual Field (HVF) with the binocular Humphrey Esterman Visual Field (HEVF) for determining whether subjects suffering from glaucoma fulfilled the new medical requirements for possession of a Swedish driver’s license.MethodsHVF SITA Fast 24–2 full threshold (monocularly) and HEVF (binocularly) were performed consecutively on the same day on 40 subjects with glaucomatous damage of varying degrees in both eyes. Assessment of results was constituted as either “pass” or “fail”, according to the new medical requirements put into effect September 1, 2010 by the Swedish Transport Agency.ResultsForty subjects were recruited and participated in the study. Sixteen subjects passed both tests, and sixteen subjects failed both tests. Eight subjects passed the HEFV but failed the HVF. There was a significant difference between HEVF and HVF (χ2, p = 0.004). There were no subjects who passed the HVF, but failed the HEVF.ConclusionsThe monocular visual field test (HVF) gave more specific information about the location and depth of the defects, and therefore is the overwhelming method of choice for use in diagnostics. The binocular visual field test (HEVF) seems not be as efficient as the HVF in finding visual field defects in glaucoma subjects, and is therefore doubtful in evaluating visual capabilities in traffic situations.

Contents Vol. 46, 2011

Anatomy, Pathology and Cell Biology A. Prescott, Dundee Biochemistry, Molecular Biology and Molecular Genetics J. Graw, Neuherberg Clinical and Epidemiological Research M. Kojima, Kahoku Cornea and Ocular Surface C. Marfurt, Gary, Ind. Glaucoma H. Th ieme, Mainz Immunology and Microbiology U. Pleyer, Berlin Lens and Cataract S. Varma, Baltimore, Md. Miscellaneous U. Pleyer, Berlin Neuro-Ophthalmology and Vision Sciences P. Aydin, Ankara Ocular Oncology M. Jager, Leiden Physiology, Pharmacology and Toxicology A. Wegener, Bonn Retina and Retinal Cell Biology P. Pereira, Coimbra Editorial Board

Maximum tolerable dose (MTD), a new index for ultraviolet radiation toxicity in the lens

The maximum tolerable dose (MTD2.3:16) for avoidance of cataract on exposure to UVR-300 nm in the rat was currently estimated to 3.65 kJ/m2. For this, Sprague-Dawley rats were unilaterally exposed to UVR in the 300 nm wavelength region, generated with a high pressure mercury arc source. The intensity of forward light scattering was measured one week after exposure. MTD allows estimation of toxicity for continuous response events with small sample experiments. Current safety standards for avoidance of cataract after exposure to UVR are based on a binary response event. It has however recently been shown that UVR-induced cataract is a continuous dose-dependent event. MTD provides a statistically well defined criterium of toxicity for continuous response events.

The Optimum Sunglass Filter

It is concluded that sunglasses shall block UVR and toxic blue light, allow transmittance of signal light and bring luminous intensity behind the filters to a comfortable level. It was found that some commercially available sunglasses, apart from one pair of photochromatic dark state lenses tested, block ultraviolet radiation (UVR) adequately. Further, it was found that it is possible to block the toxic blue radiation without interfering substantially on blue signal light perception. However, none of the sunglasses tested blocked the toxic blue light enough.