Acta Ophthalmologica Scandinavica 

About: Acta Ophthalmologica Scandinavica is an academic journal. The journal publishes majorly in the area(s): Glaucoma & Visual acuity. It has an ISSN identifier of 1395-3907. Over the lifetime, 2424 publications have been published receiving 57282 citations.

Calculation of intraocular lens power: a review.

Abstract: This review describes the principles and practices involved in the calculation of intraocular lens (IOL) power The theories behind formulas for calculating IOL power are described, using regression and optical methods employing 'thin lens' and 'thick lens' models, as well as exact ray-tracing methods Numerical examples are included to illustrate the points made The paper emphasizes the importance of establishing an accurate estimation of corneal power as well as an accurate technique for the measurement of axial length and accurate methods of predicting postoperative anterior chamber depth (ACD) It is concluded that current improvements in diagnostic and surgical technology, combined with the latest generation IOL power formulas, make the calculation and selection of appropriate IOL power among the most effective tools in refractive surgery today

A new generation of algorithms for computerized threshold perimetry, SITA

Abstract: PURPOSE: The purpose of this work was to develop a new family of test algorithms for computerized static threshold perimetry which significantly reduces test time without any reduction of data quality.METHODS: A comprehensive visual field model constructed from available knowledge of normal and glaucomatous visual fields is continuously updated during testing. The model produces threshold estimates and also estimates of the certainty to which the threshold is known at each point. Testing is interrupted at each test location at predetermined levels of threshold certainty. New time-saving methods are employed for estimation of false answers, and test pacing is optimized. After completion of the test, all threshold estimates are re-computed, taking into account the complete body of patient responses. Computer simulations were used to optimize the different parameters of the new algorithms, to evaluate the relative importance of those parameters, and to evaluate the performance of the algorithm as a whole in comparison with a standard algorithm.RESULTS: Simulated test results obtained with this algorithm were slightly more accurate than those of the Humphrey Full Threshold test algorithm. The number of simulated stimuli presented was reduced by an average of 29% in normal fields and 26% in glaucomatous fields. Actual clinical test time should be further reduced, since the influence of the improved timing algorithm was not included in the simulations.CONCLUSIONS: We applied new methods which take available knowledge of visual field physiology and pathophysiology into account, and employ modern computer-intensive mathematical methods for real time estimates of threshold values and threshold error estimates. In this way it was possible to design a family of testing algorithms which significantly reduced perimetric test time without any loss of quality in results. (Less)

Age-related maculopathy and the impact of blue light hazard.

Abstract: The pathogenesis of age-related maculopathy (ARM), the most common cause of visual loss after the age of 60 years, is indeed a complicated scenario that involves a variety of hereditary and environmental factors The pathological cellular and molecular events underlying retinal photochemical light damage, including photoreceptor apoptosis, have been analysed in experimental animal models Studies of age-related alterations of the retina and photoreceptors, the accumulation of lipofuscin in retinal pigment epithelium (RPE) cells, and the formation of drusen have greatly contributed to our knowledge A new concept of an inflammatory response to drusen has emerged, suggesting immunogenic and systemic reactions in Bruch's membrane and the subretinal space Oxidative stress and free radical damage also impact on the photoreceptors and RPE cells in the ageing eye Based on the photoelectric effect, a fundamental concept in quantum physics, the consequences of high-energy irradiation have been analysed in animal models and cell culture Short-wavelength radiation (rhodopsin spectrum), and the blue light hazard (excitation peak 440 nm), have been shown to have a major impact on photoreceptor and RPE function, inducing photochemical damage and apoptotic cell death Following cataract surgery, there is a dramatic change in ocular transmittance In aphakic or pseudophakic eyes (with clear intraocular lenses), high-energy (blue) and ultraviolet-A radiation strikes the retina Epidemiological data indicate a significantly increased 5-year incidence of late ARM in non-phakic eyes compared with phakic eyes In recent years, putative prophylactic measures against ARM have emerged The implantation of 'yellow' intraocular lenses (IOLs) that absorb high-energy blue radiation is, from a theoretical point of view, the most rational approach, and, from a practical point of view, is easy to accomplish With increasing age, RPE cells accumulate lipofuscin (chromophore A2E) It is noteworthy that the yellow IOL not only protects A2E-laden human RPE cells from blue light (peak 430 nm) damage, but also alleviates the detrimental effects of green (peak 550 nm) and white light A prophylactic treatment using antioxidants is aimed at counteracting oxidative stress and free radical cellular damage The Age-Related Eye Disease Study (AREDS), a randomized clinical trial, showed a significantly lower incidence of late ARM in a cohort of patients with drusen maculopathy treated with high doses of antioxidants than in a placebo group In recent years, considerable progress in retinal research has been achieved, creating a platform for the search for new prophylactic and therapeutic measures to alleviate or prevent photoreceptor and RPE degeneration in ARM

Identification of androgen, estrogen and progesterone receptor mRNAs in the eye.

Abstract: . Purpose: Previous research has demonstrated that sex steroids exert a significant influence on the structure and function of numerous ocular tissues. To begin to explore the underlying basis of this hormone action, we examined whether various anterior and posterior tissues of the eye contain androgen, estrogen and progesterone receptor mRNAs. Methods: Tissue samples were obtained from adult male and female rats, rabbits and humans, processed for the isolation of total RNA and analyzed by RT-PCR, agarose gel electrophoresis and Southern blot hybridization. All PCR amplifications included positive and negative controls. Results: Our findings showed that androgen, estrogen and/or progesterone receptor mRNAs are present in the lacrimal gland, lacrimal gland acinar epithelial cells, meibomian gland, lid, palpebral and bulbar conjunctivae, cornea, iris/ciliary body, lens, retina/uvea, retina/choroid and retinal pigment epithelial cells of rats, rabbits or humans. Conclusions: Our findings demonstrate that sex steroid receptor mRNAs exist in a variety of ocular tissues and suggest that these sites may represent target organs for androgens, estrogens and/or progestins.

Screening and prevention of diabetic blindness.

Abstract: Diabetic eye disease remains a major cause of blindness in the world. Laser treatment for proliferative diabetic retinopathy and diabetic macular edema became available more than two decades ago. The outcome of treatment depends on the timing of laser treatment. The laser treatment is optimally delivered when high-risk characteristics have developed in proliferative retinopathy or diabetic macular edema and before this has significantly affected vision. Laser treatment is usually successful if applied during this optimal period whereas the treatment benefit falls sharply if the treatment is applied too late. In order to optimize the timing of laser treatment in diabetic eye disease screening programs have been established. The oldest screening program is 20 years old and several programs have been established during the last decade. In this paper the organisation and methods of screening programs are described including direct and photographic screening. The incidence and prevalence of blindness is much lower in populations where screening for diabetic eye disease has been established compared to diabetic populations without screening. Technical advantages may allow increased efficiency and telescreening. From a public health standpoint screening for diabetic eye disease is one of the most cost effective health procedures available. Diabetic eye disease can be prevented using existing technology and the cost involved is many times less than the cost of diabetic blindness.