No abstract

ABSTRACT.Purpose: Hyaluronan concentration in the iris tissue after iridectomy was studied in order to establish the influence of trauma on the production of hyaluronan in the anterior chamber of the eye and whether the iris participates in this process or not.

A highly specific hyaluronic acid (HA) recognizing protein (HABR) was used to study whether the human corneal endothelium is covered by HA and to quantify the amount. Tritiated high molecular weight HA was used to determine the capacity of the human endothelium to bind exogenous HA. Human corneas were obtained from keratoconus patients having corneal transplantation and from postmortem eyes. The corneas were immersed in a 4% formaldehyde solution containing 1% cetylpyridine chloride for histochemistry, frozen for biochemistry, or used for 3H-HA (Mr 3 x 10(6) binding. For the biochemical determinations, 125I-labeled HABR was used. Tritiated HA was used for the binding experiment. A specific layer of HA covering the endothelial cells of the corneal buttons was demonstrated. The biochemical analysis also revealed the presence of HA. Finally, the human endothelial cells had specific hyaluronic acid binding sites.

ABSTRACT.Purpose: To evaluate the effect of phototherapeutic keratectomy (PTK) in combination with manual scraping when removing epithelial ingrowth under a LASIK flap. Material and Methods: Three patients, who had undergone several surgeries following LASIK in order to remove epithelial ingrowth that was threatening vision, were treated with a flap lift, manual abrasion and PTK. The PTK was performed on both the stromal and the flap side with the aim of eliminating the threat and improving vision. Two patients underwent primary surgery to remove epithelial ingrowth with manual abrasion and PTK. The influence on vision, topography and cell recurrences was evaluated. Results: Uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA) improved in four cases and remained good in the fifth case. The refraction did not change significantly. Topography disclosed changes in the irregular astigmatism, explaining the improved BSCVA. Central epithelial ingrowth did not recur, whereas peripheral ingrowth did. The peripheral ingrowth did not progress, except in case 1, where a cyst formed that required surgery. Conclusions: It is our belief that adding PTK to manual scraping improves the prognosis for eyes with epithelial ingrowth. It is mainly the central ingrowth that is positively affected. Improved adhesion between the stroma and the flap is one possible explanation.

Our findings demonstrate synthesis of hyaluronan by normal and traumatized iris. The iris seems to be the most important source of aqueous hyaluronan.