Biomedical subjects

H W Heider

Publications and source records attributed to H W Heider.

3 recordsLinked to original sources

PubMed1993

[Capsular sack suture PMMA intraocular lens. Comparative study of centering behavior after phacoemulsification and planned extracapsular cataract extraction].

The position of bag-fixated intraocular lenses after phacoemulsification or extracapsular cataract extraction (ECCE) was compared in order to determine the relationship to the method of operation and the type of capsular opening. Photographs were taken from 71 eyes 6 months after in-the-bag implantation of a one-piece posterior chamber lens. Centering was determined with respect to the pupillary center. Forty-six eyes were operated on by phacoemulsification after continuous circular capsulorhexis with closed edges and 25 eyes by ECCE after capsulorhexis with a radial incision of the capsular rim at the 12 o'clock position. Ninety-four percent of the intraocular lenses implanted after phacoemulsification and 92% of the intraocular lenses implanted after ECCE were decentered less than 0.5 mm. The centering of bag-fixated intraocular lenses is related to the technique of opening the anterior capsule. Phacoemulsification with continuous capsulorhexis offers conditions similar to that in ECCE with capsulorhexis and radial capsular rim incision for good centering of one-piece posterior chamber lenses.

Adult↗

PubMed1993

[Plasminogen activator and PAI. Detection in aqueous humor of the human eye].

Tissue-type plasminogen activator (t-PA), a serine protease that catalyzes the conversion from plasminogen to plasmin, plays an important role in the fibrinolytic system and has also in recent years attracted attention in the field of ophthalmology. In order to examine the role of t-PA in the physiology of the anterior segment, we detected t-PA in aqueous humor by using immunoassays. The samples were taken by keratocentesis prior to cataract or glaucoma surgery. The sample volumes ranged from 50-200 microliters. The quantities of t-PA Ag and plasminogen-activator inhibitor (PAI) Ag were determined by using enzyme-linked immunosorbent assays. We determined t-PA and PAI in the aqueous humor of 54 patients between 32 and 87 years of age. The t-PA Ag levels ranged from 0.2 to 1.9 ng/ml (average 0.8 ng/ml), PAI-Ag from 0.2 to 1.7 ng/ml (average 0.9 ng/ml). The values measured in men were slightly higher than those measured in women. No association between t-PA and PAI levels and accompanying diseases or metabolic disorders was noted. Precise knowledge about the presence of t-PA in aqueous humor is a prerequisite for the recognition of pathological events following intraocular fibrin formation and may be an important basis for the therapeutic use of rt-PA in the intraocular inflammatory process.

Adult↗

PubMed1991

[Changes in the visual field caused by lens opacities].

60 eyes with advanced opacity of the lens nucleus and a corrected visual acuity of at least 0.1 have been examined by Octopus perimetery before and after a cataract extraction with posterior chamber lens implantation. 20 eyes had chronic glaucoma with glaucomatous alterations of the optic nerve head. Our purpose was to determine the effect of lens opacities on the result of automated perimetry especially in view of glaucomatous field defects. The influence of the cataract on the differential light threshold in the whole field (30 degrees) area showed a wide variance. The calculated visual field indices loss variance (LV) and corrected loss variance (CLV) did not clearly separate glaucomatous from cataractous field changes. Often an exact analysis of the numerical printout of the visual field helps in finding of localized glaucomatous field defects.

Adult↗