[Standardisation of optotypes]. / Standardizacija optotipa.

Optotypes are signs of different sizes, systematically placed on the visual acuity chart. The human eye has a spatial resolution of 1' of arc (Snellen). Optotypes in the basic row on all charts subtend 5' of arc and their detail 1' of arc, from the testing distance. The disadvantage of all classical charts is the irregular progresssion of optotype sizes in adjacent rows. This was solved by logMAR (Bailey-Lovie) chart in 1976. The chart was made with optotype sizes in steps with a constant ratio 1:1.2589 (geometric progression). This chart has become the standard for visual acuity testing worldwide. It has been recommended by the following bodies: International Council of Ophthalmology (ICO), 1984 and 2002; World Health Organisation (WHO), 2003; International Organisation for Standardisation (ISO) 1996, and Croatian Standard Institute homologised the ISO standard as nHRN EN ISO 8596:1996. For normative, medical and practical reasons it is advised that all school medicine, occupational health and ophthalmology departments adopt the logMAR charts system.

[Haemosiderosis bulbi in a patient with myelodysplastic syndrome (MDS RAEB-1)]. / Haemosiderosis bulbi kod pacijenta s mijelodisplasticnim sindromom (MDS RAEB-1).

Haemosiderosis bulbi is a degenerative condition of the eye bulb caused by the toxic effects of an intracellular accumulation of haemosiderin. Haemosiderin is a product of the decomposition of haemoglobin. The most common and severe damage takes place in the epithelial cells of the eye tissues. Haemosiderosis bulbi is a complication of the long existing haemophthalmus, the intravitreal bleeding, which is neither spontaneously resorbed nor operatively removed. The condition is characterized by the loss of light perception and the reddish colour of the intrabulbar tissues. The cause of the haemophthalmus in our patient is protracted anaemia due to pre-existing myelodysplastic syndrome (MDS RAEB-1).