Graefes Archive for Clinical and Experimental Ophthalmology 

About: Graefes Archive for Clinical and Experimental Ophthalmology is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Visual acuity & Glaucoma. It has an ISSN identifier of 0721-832X. Over the lifetime, 10242 publications have been published receiving 216363 citations. The journal is also known as: Graefe's archive for clinical and experimental ophthalmology (Print).

Comparison of immersion ultrasound biometry and partial coherence interferometry for intraocular lens calculation according to Haigis

Abstract: Background: The precision of intraocular lens (IOL) calculation is essentially determined by the accuracy of the measurement of axial length. In addition to classical ultrasound biometry, partial coherence interferometry serves as a new optical method for axial length determination. A functional prototype from Carl Zeiss Jena implementing this principle was compared with immersion ultrasound biometry in our laboratory. Patients and methods: In 108 patients attending the biometry laboratory for planning of cataract surgery, axial lengths were additionally measured optically. Whereas surgical decisions were based on ultrasound data, we used postoperative refraction measurements to calculate retrospectively what results would have been obtained if optical axial length data had been used for IOL calculation. For the translation of optical to geometrical lengths, five different conversion formulas were used, among them the relation which is built into the Zeiss IOLMaster. IOL calculation was carried out according to Haigis with and without optimization of constants. Results: On the basis of ultrasound immersion data from our Grieshaber Biometric System (GBS), postoperative refraction after implantation of a Rayner IOL type 755U was predicted correctly within ±1 D in 85.7% and within ±2 D in 99% of all cases. An analogous result was achieved with optical axial length data after suitable transformation of optical path lengths into geometrical distances. Conclusions: Partial coherence interferometry is a non- contact, user- and patient-friendly method for axial length determination and IOL planning with an accuracy comparable to that of high-precision immersion ultrasound.

Improvements on Littmann's method of determining the size of retinal features by fundus photography.

Abstract: Littmann's formula relating the size of a retinal feature to its measured image size on a telecentric fundus camera film is widely used. It requires only the corneal radius, ametropia, and Littmann's factor q obtained from nomograms or tables. These procedures are here computerized for practitioners' convenience. Basic optical principles are discussed, showing q to be a constant fraction of the theoretical ocular dimension k′, the distance from the eye's second principal point to the retina. If the eye's axial length is known, three new methods of determining q become available: (a) simply reducing the axial length by a constant 1 · 82 mm; (b) constructing a personalized schematic eye, given additional data; (c) ray tracing through this eye to extend calculations to peripheral retinal areas. Results of all these evaluations for 12 subjects of known ocular dimensions are presented for comparison. Method (a), the simplest, is arguably the most reliable. It shows good agreement with Littmann's supplementary procedure when the eye's axial length is known.

Twelve-month safety of intravitreal injections of bevacizumab (Avastin): results of the Pan-American Collaborative Retina Study Group (PACORES).

Abstract: Vascular endothelial growth factor (VEGF) plays an important role in many diseases of the posterior pole that are characterized by macular edema and/or intraocular neovascularization. Recently anti-VEGF agents such as ranibizumab and pegaptanib sodium have been shown to be beneficial in the treatment of choroidal neovascularization (CNV) secondary to age-related macular degeneration (ARMD). However in most parts of the world, both pegaptanib sodium and ranibizumab are not readily available. Bevacizumab, a humanized recombinant monoclonal IgG antibody that binds and inhibits all VEGF isoforms, has been proposed as an alternative treatment option. A total of 1,265 consecutive patients were injected with bevacizumab for diseases such as proliferative diabetic retinopathy, diabetic macular edema, retinal vein occlusions, and CNV of several etiologies including ARMD at eight Latin American institutions from 1 September 2005 to 31 January 2006. Of these 1,265, 92 were excluded because they were injected once and lost to follow-up. The remaining 1,173 patients constitute the subjects of this retrospective, multicenter, open label, uncontrolled interventional case series that reports the cumulative systemic and ocular adverse events following intravitreal bevacizumab during 12 months of follow-up. Patients were examined at baseline and then monthly. If the patients were unable to attend the 12-month visit, a telephone interview was conducted to assess for possible systemic complications. A total of 4,303 intravitreal injections of bevacizumab on 1,310 eyes was reported. All 1,173 patients were accounted for at the 12-month visit. Systemic adverse events were reported in 18 (1.5%) patients. These included seven (0.59%) cases of an acute elevation of systemic blood pressure, six (0.5%) cerebrovascular accidents, five (0.4%) myocardial infarctions, two (0.17%) iliac artery aneurysms, two (0.17%) toe amputations and five (0.4%) deaths. Ocular complications included seven (0.16%) bacterial endophthalmitis, seven (0.16%) tractional retinal detachments, four (0.09%) uveitis, and a case (0.02%) each of rhegmatogenous retinal detachment and vitreous hemorrhage. Despite the limited follow-up, repeated intravitreal injections of either 1.25 mg or 2.5 mg of bevacizumab appears to be safe and well tolerated during the 1st year.

Resolving the clinical acuity categories "hand motion" and "counting fingers" using the Freiburg Visual Acuity Test (FrACT).

Abstract: The Freiburg Visual Acuity Test (FrACT) has been suggested as a promising test for quantifying the visual acuity (VA) of patients with very low vision, a condition often classified using the semi-quantitative clinical scale “counting fingers” (CF), “hand motion” (HM), “light perception” (LP) and “no light perception”. The present study was designed to assess FrACT performance in a sizable number of CF, HM, and LP patients in order to generate a setting for future clinical studies in the low vision range. We examined a total of 41 patients (LP, n = 11; CF, n = 15; HM, n = 15) with various eye diseases (e.g., diabetic retinopathy, ARMD), covering the clinical VA scale from LP to CF. The FrACT optotypes were presented at a distance of 50 cm on a 17-inch LCD monitor with four random orientations. After training, two FrACT measurements (test and retest) were taken, each comprising 30 trials. FrACT measures reproducibly the VA of CF and HM patients. In CF patients, FrACT resulted in a mean logMAR = 1.98 ± 0.24 (corresponding to a decimal VA of 0.010), for HM in a mean logMAR = 2.28 ± 0.15 (corresponding to a decimal VA of 0.0052). In all LP patients the FrACT values were close to what would be obtained by random guessing. The mean test–retest 95% confidence interval was 0.21 logMAR for CF patients and 0.31 logMAR for HM respectively. Test-retest variability declined from 24 to 30 trials, showing that at least 30 trials are necessary. FrACT can reproducibly quantify VA in the CF and HM range. We observed a floor effect for LP, and it was not quantifiable further. Quantitative VA measures are thus obtainable in the very low-vision range using FrACT.

Anomalous posterior vitreous detachment: a unifying concept in vitreo-retinal disease

Abstract: Posterior vitreous detachment (PVD) is the consequence of changes in the macromolecular structure of gel vitreous that result in liquefaction, concurrent with alterations in the extracellular matrix at the vitreo-retinal interface that allow the posterior vitreous cortex to detach from the internal limiting lamina of the retina. Gel liquefaction that exceeds the degree of vitreo-retinal dehiscence results in anomalous PVD (APVD). APVD varies in its clinical manifestations depending upon where in the fundus vitreo-retinal adhesion is strongest. At the periphery, APVD results in retinal tears and detachments. In the macula, APVD causes vitreo-macular traction syndrome, results in vitreoschisis with macular pucker or macular holes, or contributes to some cases of diabetic macular edema. At the optic disc and retina, APVD causes vitreo-papillary traction and promotes retinal and optic disc neovascularization. Unifying the spectrum of vitreo-retinal diseases into the conceptual framework of APVD underscores that to more effectively treat, and ultimately prevent, these disorders it is necessary to replicate the two components of an innocuous PVD, i.e., gel liquefaction and vitreo-retinal dehiscence. Pharmacologic vitreolysis is designed to mitigate against APVD by chemically breaking down vitreous macromolecules and weakening vitreo-retinal adhesion to safely detach the posterior vitreous cortex. This would not only facilitate surgery, but if performed early in the natural history of disease, it should prevent progressive disease.