Miltiadis K. Tsilimbaris

Choice of Analytic Approach for Eye-Specific Outcomes: One Eye or Two?

PURPOSEnTo investigate the use of analytic approaches for eye-specific outcomes in ophthalmology publications.nnnDESIGNnA review of analytic approaches used in original research articles published in ophthalmology journals.nnnMETHODSnAll 161 research articles published in 5 ophthalmology journals in the first 2 months of 2008 were considered. Publications were categorized according to analytic approach: 1 eye selected, both eyes contribute, or per-individual outcome. Studies were considered suboptimal when criteria for eye selection were not provided or when measurements from both eyes were included without interocular correlation being considered. Visual impairment prevalence data were used to illustrate analytic approach choices.nnnRESULTSnMeasurements from both eyes were included in 38% of the 112 studies that used statistical inferential techniques. In 31 (74%), there was no mention of possible correlation. Only 7% used statistical methods appropriate for correlated outcomes. In 35 studies (31%), measurements from 1 eye were selected; 31% of these did not provide selection criteria. In 67%, only univariate tests were used. A review of 47 articles published in 2011 produced similar findings. Characteristics of studies were not found to differ according whether the studies were suboptimal. Using a test appropriate for correlated outcomes resulted in a P value 3.5 times that obtained ignoring the correlation.nnnCONCLUSIONSnBetween-eye correlation seems not to be assessed commonly in ophthalmology publications, although its knowledge aids the choice of analytic approach when eye-specific variables are of interest. Statistical methods appropriate for correlated ocular outcome data are not being applied widely.

Assessment of macular pigment optical density (MPOD) in patients with unilateral wet age-related macular degeneration (AMD)

Purpose:u2002 To compare the macular pigment optical density (MPOD) of patients with unilateral wet age‐related macular degeneration (AMD) with the MPOD of bilateral dry AMD patients and healthy elderly individuals.

Photothrombosis of retinal and choroidal vessels in rabbit eyes using chloroaluminum sulfonated phthalocyanine and a diode laser.

Photothrombosis is a relatively new photodynamic application leading to vascular occlusion. In the current work the effectiveness of phthalocyanine and a diode laser in photothrombosis of normal retinal and choroidal vessels was evaluated.

Myopia and visual acuity impairment: a comparative study of Greek and Bulgarian school children

Purpose:u2002 To compare the proportions of school children with myopia and impaired visual acuity in Greece and Bulgaria.

PHOTOTHROMBOSIS USING TWO DIFFERENT PHTHALOCYANINE ADMINISTRATION ROUTES: CONTINUOUS I.V. INFUSIO versus BOLUS I.V. INJECTION

Chloraluminum sulfonated phthalocyanine was administered in 22 albino rabbits either by means of bolus i.v. (intravenous) injection (6 mg/kg) or as continuous i.v. infusion. Eight animals were used for the comparison of plasma phthalocyanine change as a factor of time, using the two administration methods. Photothrombosis of corneal neovascularization was carried out in the remaining 14 animals either after bolus phthalocyanine injection or after continuous i.v. infusion. Irradiation of the right eyes vessels started 10 min after the injection in the bolus group and 35 min after initiation of infusion in the continuous infusion group. The vessels of each animals left eye were irradiated 1 h after the irradiation of the right eye. The initial peak of phthalocyanine concentration after bolus injection was followed by a rapid decrease of plasma levels. In the continuous infusion group,30–40 min after the initiation of infusion, plasma phthalocyanine concentration reached a plateau that remained stable for the rest of the80–90 min of infusion. Using bolus injection, a significant decrease of phthalocyanine concentration was accompanied by a significant increase of irradiation time necessary for neovascularization thrombosis in the two eyes. Irradiation time as well as phthalocyanine concentration did not differ between the two eyes using continuous infusion. Vascular photosensitivity seemed to be higher using continuous i.v. infusion of phthalocyanine. Continuous i.v. infusion represents an interesting alternative to bolus injection for phthalocyanine‐mediated corneal neovascularization photothrombosis.

In vivo evaluation of blue-light attenuation with tinted and untinted intraocular lenses.

PURPOSE: To evaluate blue‐light attenuation in eyes with a tinted intraocular lens (IOL) or an untinted IOL. SETTING: Department of Ophthalmology, University Hospital of Crete, Crete, Greece. DESIGN: Comparative case series. METHODS: Patients had lens extraction and implantation of an Acrysof Natural tinted or Tecnis ZA9003 or Softec III untinted acrylic IOL. The luminance ratio of green (530 nm) and blue (465 nm) light (green:blue ratio) required for isoluminant perception was determined by heterochromatic flicker photometry. Patients were tested preoperatively and 20 days postoperatively. The parafoveal measure of the green:blue ratio, expressed in decibels, is proportional to the blue‐light attenuation by the lens. RESULTS: Twenty‐two patients received the tinted IOL and 21 the untinted IOL. Preoperatively, age was strongly linearly correlated with the green:blue ratio (r = 0.59, P<.001). The mean postoperative decrease in the green:blue ratio was greater in the untinted IOL group (P=.003). Postoperatively, the tinted IOL group had a significantly higher green:blue ratio than the untinted IOL group (P<.001). In the tinted IOL group, the green:blue ratio was linearly related to IOL dioptric power. CONCLUSION: Less blue light reached the retina with tinted IOLs than with untinted IOLs. The absorption properties of tinted IOLs seemed to resemble those of the aging human crystalline lens, while untinted IOLs resembled the lower levels of blue‐light attenuation of younger lenses. Thus, tinted IOLs may protect against the presumed blue‐light hazard. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Assessment of macular pigment optical density in patients with unilateral wet age‐related macular degeneration: authors reply

Department of Ophthalmology, Faculty of Medicine, University Hospital of Heraklion, Crete, Heraklion, Greece Institute of Vision & Optics, Faculty of Medicine, School of Health Sciences, University of Crete, Crete, Greece Department of Optometry and Neuroscience, Faculty of Life Sciences, University of Manchester, Manchester, UK Preventive Medicine and Nutrition Clinic, Division of Social Medicine, Faculty of Medicine, School of Health Sciences, University of Crete, Crete, Greece