Our objective was to determine whether key properties of extracellular matrix (ECM) macromolecules can be replicated within tissue-engineered biosynthetic matrices to influence cellular properties and behavior. To achieve this, hydrated collagen and Nisopropylacrylamide copolymer-based ECMs were fabricated and tested on a corneal model. The structural and immunological simplicity of the cornea and importance of its extensive innervation for optimal functioning makes it an ideal test model. In addition, corneal failure is a clinically significant problem. Matrices were therefore designed to have the optical clarity and the proper dimensions, curvature, and biomechanical properties for use as corneal tissue replacements in transplantation. In vitro studies demonstrated that grafting of the laminin adhesion pentapeptide motif, YIGSR, to the hydrogels promoted epithelial stratification and neurite in-growth. Implants into pigs' corneas demonstrated successful in vivo regeneration of host corneal epithelium, stroma, and nerves. In particular, functional nerves were observed to rapidly regenerate in implants. By comparison, nerve regeneration in allograft controls was too slow to be observed during the experimental period, consistent with the behavior of human cornea transplants. Other corneal substitutes have been produced and tested, but here we report an implantable matrix that performs as a physiologically functional tissue substitute and not simply as a prosthetic device. These biosynthetic ECM replacements should have applicability to many areas of tissue engineering and regenerative medicine, especially where nerve function is required.regenerative medicine ͉ tissue engineering ͉ cornea ͉ implantation ͉ innervation

A series of 122 eyes with band keratopathy was treated by excimer laser phototherapeutic keratectomy (PTK), with a mean foliow up of over 12*3 months (range 3 to 60 months). A single photoablation zone was used to remove the opacity over the visual axis in smooth surfaced band deposition. In eyes with reduced vision, an improvement was reported in 88% and in a series of 66 eyes mean Snelien visual acuity increased significantly (p<005, t=2-27). A reduction in glare was reported in 88% and in a series of 17 patients, visual contrast sensitivity (p<001) and measurements of disability glare (p<001) improved postoperatively. The mean hyperopic shift in 32 eyes at 6 months was 1.4 D (range 0-4-25 D).Multiple overlapping ablation zones, with mechanical debulking of large calcium plaques, were used to smooth the irregular corneal surface in eyes with rough bands. Ocular discomfort was improved in 95%. Band keratopathy recurred in nine eyes (8%) within 2 to 30 months (mean 12 months) of surgery, with silicone oil responsible in five eyes. Reablation was necessary in three eyes and performed successfuliy in all cases. Excimer laser PTK is a safe and effective outpatient treatment for band keratopathy. (BrJ Ophthalmol 1993; 77: 702-708)

Postoperative changes in corneal transparency is a major concern after PRK. Data were obtained from 69 human eyes treated with excimer laser photorefractive keratectomy in order to evaluate a relationship between objective measurements of corneal transparency and visual performance. A CCD-camera device was employed and by using polarizing filters the system could discriminate between reflected and scattered light. We observed two groups of postoperative behaviour in corneal transparency. Each group showed an increase in both scattered and reflected light signals with a maximum at around two months postoperatively. In the majority group (70%) this was followed by a subsequent decline of the scattered light signal, whereas the combined signal generated by reflected and scattered light showed a biphasic curve with a second peak at around 4 to 5 months postoperatively. In the minority patient group (30%) the timebase variations in pattern of both signals were indistinguishable throughout the period of observation. In all patients we observed a good correlation between the signal generated by scattered light alone and the reduction in the 5% contrast visual acuity performance, whereas correlation was poor when the combined signal of reflected and scattered light was considered. These disturbances in low contrast visual performance were only significant during the first three to four months postoperatively and thereafter most patients returned to their preoperative value. Eighteen percent of our patients discontinued topical steroids postoperatively. No differences in either corneal transparency or final refraction was observed. We consider that PRK is an effective form of refractive surgery and the marginal loss of corneal transparency should only be a problem during the first three or four months postoperatively.

Aim: To investigate macular function and morphology after surgical removal of idiopathic epiretinal membrane (IEM) with and without assistance of indocyanine green (ICG). Methods: A retrospective study as a consecutive case series, of 39 patients with IEM. 39 patients, 23 female, 16 male, mean age 67 years, underwent standard three port pars plana vitrectomy with removal of epiretinal membrane. Two groups of patients were consecutively operated: in 20 patients ICG 0.1% in glucose 5% was used to stain the epiretinal membrane. 19 patients underwent the identical procedure but without use of ICG. Postoperative follow up was 1-92 months (mean 15.5 months). Functional outcome was assessed with subjective improvement, best corrected visual acuity (BCVA), Amsler grid test, 10˚and 30˚automated perimetry (Heidelberg visual field analyser) (HFA), and Goldmann kinetic perimetry. Macular morphology was assessed with stereoscopic biomicroscopy and optical coherence tomography (OCT). The main outcome measures were macular function as determined by BCVA, presence of visual field defects, and metamorphopsia as determined by Amsler grid test, macular morphology as determined by slit lamp biomicroscopy, and OCT. Results: BCVA improved in 28 patients, remained unchanged in eight patients, and decreased in three patients. Improvement of BCVA was statistically significant in both groups (p = 0.003). Mean BCVA in patients operated with ICG improved from 0.33 preoperatively to 0.53 postoperatively. Mean BCVA in patients operated without ICG improved from 0.32 preoperatively to 0.54 postoperatively. Reduction of macular oedema as measured by OCT was statistically significant in both groups (p,0.01). There was no statistically significant difference in postoperative BCVA, macular oedema as measured by OCT, postoperative Amsler grid test, and subjective improvement between the two groups. The incidence of residual or recurrent epiretinal membrane was greater in the group operated without ICG (p = 0.014). Visual field defects were detected in one patient operated with ICG and in three patients operated without ICG. Conclusions: Removal of epiretinal tissue with or without assistance of ICG improved visual function and reduced macular oedema in most patients. Adverse effects clearly attributable to the use of ICG were not observed but further investigation is warranted.

Our histopathological results indicate that corneal wound healing after excimer laser PRK varies among individuals. In some people epithelial basement proteins, such as collagen type IV, are the main wound healing products, whereas in others mainly collagen type III is found postoperatively, which does not effect the synthesis of collagen type IV. This suggests the need for individually-tailored postoperative pharmaceutical treatment regimens.

Management of pain is difficult in many eye diseases. Particularly in patients undergoing surgical procedures, postoperative intractable pain is a major concern and severely influences the patient's comfort. We present 13 patients (eight male, five female, mean age 36 years) in whom sumatriptan, a highly selective 5-HT1B/1D agonist that is normally used as a specific anti-migraine drug, was used for the treatment of pain following photorefractive keratectomy (PRK). In two patients both eyes were operated on different days, resulting in a total of 15 operated eyes. A positive clinical response was achieved in all patients. In particular, in four patients, who received a second dose prophylactically 4 h following the first dose and before the recurrence of pain, we achieved excellent efficacy and stable control of pain. Further controlled studies are needed to investigate the usefulness of 5-HT1B/1D agonists in painful eye conditions.

For further assessment of this treatment controlled clinical trials are urgently required as this therapy would offer a new approach for patients with chronic CSCR and no tendency towards recovery.

Purpose To discuss the influence of AMD on critical flicker fusion frequency (CFF) Methods CFF was measured centrally for red, green and blue signal and in 10° excentricity with a red signal. 33 patients with non exsudative AMD and a visual acuity (VA) of 20/100‐20/20, 12 patients with exsudative AMD (VA: 20/100‐20/25) and 45 age‐matched healthy eyes (VA: 20/32‐20/20) were included. Results CFF decreased in eyes with non exsudative AMD (red 1,6Hz p=0,01, green 1,6 Hz p=0,04, blue 2,1 Hz p=0,01). The difference between central and peripher CFF increased (red‐red 10°, 1,0 Hz p=0,01). Differences between different colours were low and reached no significance. In eyes with exsudative AMD CFF showed lower values (red 2.2 Hz p=0.02, green 3.3 Hz p=0.001, blue 2,9 Hz p=0.02, but in spite of increased difference between central and peripher CFF had no statistical significance. (red‐red 10° , 1,3 Hz p=0,25). Eyes with exsudative AMD showed a 1.0 Hz (p=0.02) higher difference between CFF with a red and a green signal than healthy eyes. Sub‐group analysis of patients with non exsudative AMD and visual acuity better than 20/32 (n=20) and healthy eyes showed no difference. Patients with non exsudative (n=13) and eyes with exsudative AMD (n=7) and VA between 20/200 and 20/40 reached equal CFF values. Conclusion CFF was decreased in non exsudative and exsudative AMD. The difference between central and peripher CFF increased in exsudative and nonexsudative AMD. Exsudative AMD has a stronger impact on a green than on a red signal. CFF is not able to distinguish between groups of equal visual acuity and therefore not applicable as a diagnostic test.