The role of complement activation in the pathogenesis of Fuchs' dystrophy.

PURPOSE: Inflammation can be an etiologic factor of Fuchs' dystrophy according to previous studies. Our aim was to analyse the activation of the complement system in the aqueous humor in this pathological condition. METHODS: 100 µl aqueous humor sample was taken during keratoplasty of 11 Fuchs' dystrophic patients and during phacoemulsification surgery of 18 control patients. The samples were mixed with EDTA and stored at -80 °C. Concentrations of C1rC1sC1Inh and C3bBbP complexes as markers of the activation of the classical and alternative complement pathways, respectively, were measured with ELISA method. The results of the patient group and the control group were compared with statistical analysis (non-parametric Mann Whitney test). RESULTS: Both the concentrations of C1rC1sC1Inh [4.3 (3.2-20.2)AU/ml] and of C3bBbP [15.3 (7.8-22.6)AU/ml] were significantly higher in the Fuchs' dystrophic group than in the control group [C1rC1sC1Inh: 0.0 (0.0-5.6)AU/ml, C3bBbP: 1.4 (0.0-7.8)AU/ml]. The median value is shown along with the (25% and 75% percentiles). CONCLUSIONS: Based on our results, the complement system may be activated both through the classical and alternative pathways in the aqueous humor of the patients with Fuchs' dystrophy.

Complement activation in the aqueous humor of pseudophakic bullous keratopathy patients.

BACKGROUND/AIMS: According to some studies, inflammation is a potential etiological factor in pseudophakic bullous keratopathy (PBK). Our aim was to obtain information on the activation of the complement system in the aqueous humor in this disorder. METHODS: Aqueous humor samples were collected during keratoplasty of 12 PBK patients, as well as during phacoemulsification surgery of 18 control patients. The concentrations of the protein-protein complexes generated during complement activation (C1rC1sC1inh and C3bBbP) through the classical and alternative pathways, respectively, as well as of the C3 cleavage product C3a, were measured with ELISA methods. The correlation among the complement factors and between the duration of the edema, the stage of the disease, and the level of the complement activation products was examined. RESULTS: The concentration of C1rC1sC1inh, C3bBbP complex and C3a was significantly higher in the PBK group (p < 0.001) compared to the control group. In PBK patients, a correlation was found between the levels of the C1rC1sC1inh complex and C3a only. CONCLUSION: Our new findings indicate that in PBK the complement system is activated - via the classical pathway - in the aqueous humor. The activated complement may play a role in increased endothelial cell loss.

The evaluation of tonometry and self-tonometry with Ocuton tonometers.

BACKGROUND: The purpose of the present study was to evaluate the clinical applicability of the Ocuton-A and Ocuton-S applanation tonometers, and to compare their use and accuracy parameters to those of Goldmann applanation tonometry (GAT). MATERIAL/METHODS: In the first study, intraocular pressure (IOP) was measured with an Ocuton-A tonometer, followed by another measurement using GAT in 15 subjects (30 eyes). Ocuton-tonometry was performed on three occasions separated by three-minute intervals. In Study 2 the impact of increased patient familiarity on measurement accuracy using the self-tonometer was investigated in 5 subjects (10 eyes) by comparing two consecutive series of five Ocuton-S measurements. In Study 3 nine trained volunteers measured their own IOP with an Ocuton-S self-tonometer after GAT and Ocuton-A measurements by an experienced investigator. RESULTS: Study 1 showed that the measured IOP value was significantly higher using the Ocuton-A tonometer, compared to values obtained using GAT. In Study 2 we found that increased practice in self-tonometry did not alter measurement accuracy. In Study 3 the difference between IOP readings obtained with the Ocuton-S and Ocuton-A instruments was not significant. CONCLUSIONS: The portable Ocuton-A tonometer may become a useful instrument for IOP measurement by professional workers outside the clinic. Qualified patients are able to use the Ocuton-S self-tonometer reliably even after limited training, and its measurement accuracy is acceptable for IOP monitoring. Both the Ocuton A and S devices consistently overestimate the IOP by approximately 2 mm Hg compared to the corresponding Goldmann readings.

The role of ultraviolet-B in corneal healing following excimer laser in situ keratomileusis.

Corneal photoablation with the 193 nm argon fluoride excimer laser during photorefractive keratectomy (PRK) in high diopter range is frequently associated with subepithelial haze and consequent refractive regression due to avascular corneal wound healing. The wound healing response can be augmented by Ultraviolet-B (UV-B) exposure originating from sun or solarium. Clinically Laser in situ Keratomileusis (LASIK) even in high diopter range is associated with less subepithelial haze and regression than PRK. In an animal model, the morphologic changes of the rabbit cornea were evaluated following LASIK and secondary UV-B exposure. Light microscpic changes were found to be insignificant. Transmission electron microscopy (TEM) normal epithelium, epithelial adhesion structures and normal anterior stroma showed in the LASIK treated UV-B irradiated rabbit eyes. Around the peripheral LASIK cut, migrating keratocytes with pseudopodia were observed. Under the flap (160 microm depth) the overall stromal collagen structure was normal, some activated keratocytes and mild extracellular matrix formation within and around keratocytes were noted. Within activated keratocytes TEM showed prominent rough endoplasmic reticulum, Golgi apparatus, mitochondria and extracellular vacuoles, which showed resolution with time. These changes were much milder than in PRK treated-UV-B irradiated eyes. Secondary UV-B caused no long-term disturbance in corneal transparency in LASIK and UV-B treated rabbit eyes.