Paolo Cecchini

Lens epithelial cell reaction after implantation of different intraocular lens materials: Two-year results of a randomized prospective trial

PURPOSE To determine the influence of intraocular lens (IOL) material on anterior capsular opacification and membrane growth over the anterior IOL surface in patients who have undergone standardized small-incision cataract surgery and foldable IOL implantation in the capsular bag. DESIGN Randomized controlled trial. PARTICIPANTS Eighty-eight cataract patients (88 eyes). METHODS Patients were randomly assigned to receive one of four different foldable IOLs after phacoemulsification: Storz Hydroview H60M, Corneal ACR6D, AMO SI40NB, and Alcon AcrySof MA60BM. Examinations on days 7, 30, 90, 180, 360, and 720 after surgery included ophthalmologic examination, slit-lamp biomicroscopy, and photography using red reflex and focal illumination of the anterior IOL surface. MAIN OUTCOME MEASURES Best-corrected visual acuity was measured at each examination. In addition, the anterior capsule opacification and the membrane growth on the anterior IOL surface were graded according to a subjective method by the same researcher. RESULTS The fibrosis of the anterior capsule was more frequently observed in the group using Corneal ACR6D and AMO SI40NB. The Hydroview and ACR6D groups showed a higher percentage of cases with membrane growth from the rhexis edge on the anterior IOL surface. AcrySof showed the lowest presence of fibrosis of the anterior capsule, and no membrane growth was noted. CONCLUSIONS Anterior capsule opacification is an index of IOL biocompatibility. The natural location of lens epithelial cells (LECs) precludes the possibility of the IOLs design influencing the anterior capsule behavior. The local response of LECs varies according to the IOL studied. This may be related to the chemical and physical properties of the materials used in the different IOLs.

Survey of ophthalmic viscosurgical devices.

Purpose of review Cataract treatment is evolving, thanks to new phaco systems and innovative surgical techniques. Recent ophthalmic viscosurgical devices (OVDs) play an important role in the development of new approaches to surgery. Knowledge of the new techniques and advances in new OVDs is crucial to performing routine and complicated surgeries. Recent findings Viscoadaptive substances have been introduced as a particular kind of OVD and are distinguished by high viscosity at a low flow rate and a tendency to fracture at higher flow rates, assuming pseudodispersive behavior. The ultimate soft shell technique emphasizes the rheology of viscoadaptive OVDs to perform phacoemulsification procedures, exploiting all the useful properties of these OVDs in terms of space maintenance and tissue protection. Recent studies have highlighted some new and interesting aspects of the use of OVDs. Current reports suggest that the association of lidocaine and OVD seems to be safe and useful in providing anesthesia during cataract surgery. Concern has been expressed in other studies regarding the presence of contaminants, such as endotoxins, which may be responsible for postoperative uveitis-like reactions. Finally, OVDs are widely known to protect the corneal endothelium during cataract surgery. Their role is also assuming relevance in vitreoretinal surgery. Summary New OVDs and related techniques represent an advancement in cataract surgery.

Correlation between the Retinal Nerve Fiber Layer Thickness and the Pattern Electroretinogram Amplitude

Objective: To establish a correlation between the retinal nerve fiber layer (RNFL) thickness measured by a scanning laser polarimeter (GDx) and the pattern electroretinogram (p-ERG) amplitudes in a heterogeneous population sample composed of normal subjects, ocular hypertensive and glaucomatous patients. Methods: 112 subjects were considered: 40 glaucomatous patients, 39 ocular hypertensive and 33 normal subjects. All were examined with the GDx, and the RNFL thickness was measured. A transient p-ERG was then recorded. Results: A statistically significant correlation was observed between the RNFL thickness and the p-ERG amplitudes (p < 0.001) by means of linear regression analysis. Conclusion: We observed a strict correlation between the measurements of the RNFL thickness obtained with the GDx and the amplitude of the p-ERG signal. These techniques represent additional objective tools to detect an early glaucomatous damage.

Comparative evaluation of corneal epithelial permeability after the use of diclofenac 0.1% and flurbiprofen 0.03% after phacoemulsification

Purpose: To assess the corneal epithelial function after prolonged topical administration of diclofenac 0.1% and flurbiprofen 0.03% single‐dose eyedrops. Setting: University Eye Clinic of Trieste, Trieste, Italy. Methods: This randomized prospective study comprised 24 patients scheduled for phacoemulsification. The patients were randomly assigned to receive diclofenac or flurbiprofen eyedrops for 2 months after surgery. Corneal epithelial permeability was determined by fluorophotometry 7, 37, and 67 days after surgery. Results: An increase in corneal epithelial permeability was observed in the diclofenac group 37 and 67 days after surgery. No epithelial function alterations occurred in the flurbiprofen group. Conclusions: Subclinical impairment of the epithelial function was observed during topical treatment with diclofenac 0.1% single‐dose eyedrops after phacoemulsification. The mechanism responsible for this effect remains unknown.

Chemical and physical analysis of phaco handpiece tip surfaces before and after cataract surgery

PURPOSE To evaluate the surface chemical composition and roughness of different phaco tips before and after their use during cataract surgery. SETTING Eye Clinic, University of Trieste, Trieste, Italy. DESIGN Experimental study. METHODS Of the 66 tips studied, 33 (15 new, 15 after single use, and 3 after multiple uses) were studied with X-ray photoemission spectroscopy and 33 (15 new, 15 after single use, and 3 after multiple uses) were examined using scanning electron microscopy with energy dispersive X-ray spectroscopy analysis and contact profilometry. All analyses were performed on the far end of the tip. RESULTS Used phaco tips showed signs of wear at the end of the tip, with the deposition of debris. The cutting edge appeared to be rounded and irregular. After surgery, an increase in the surface roughness was detected. The chemical analyses showed modification of the superficial alloy composition and the biological origin of some debris deposited after surgery. The deterioration and wear observed were more remarkable after multiple surgical procedures. CONCLUSIONS Used phaco tips showed relevant signs of deterioration and deposition of biological material, mostly involving the cutting edge. Reusable tips might release remnants of previous procedures. The adoption of single-use disposable phaco tips seems to be highly advisable.

Subretinal recombinant tissue plasminogen activator and pneumatic displacement for the management of subretinal hemorrhage occurring after anti-VEGF injections for wet AMD

We describe three cases of submacular hemorrhage that occurred two to four days after anti-VEGF intravitreal injection for occult choroidal neovascularisation in age-related macular degeneration and their management with 25 gauge pars plana vitrectomy with injection of subretinal recombinant tissue plasminogen activator (rTPA) followed by fluid-air exchange and postoperative prone position. Vitrectomy, subretinal rTPA injection and fluid-gas exchange apply as a safe and effective treatment in these cases. Functional results seem to be positive especially if surgical treatment is promptly performed.

Mixed polymeric systems: New ophthalmic viscosurgical device created by mixing commercially available devices

PURPOSE To evaluate the rheological properties of mixtures of different commercially available ophthalmic viscosurgical devices (OVDs) containing sodium hyaluronate and chondroitin sulfate. SETTING Eye Clinic, University of Trieste, Trieste, Italy. DESIGN Laboratory study. METHODS Blends were obtained combining a superviscous cohesive OVD (Healon GV [sodium hyaluronate 1%]) and a medium-viscosity dispersive OVD (Viscoat [sodium hyaluronate 3.0%-chondroitin sulfate 4.0%]). The 2 substances were combined in different ratios, and the rheological characteristics were analyzed to find the optimum proportion. A new viscous dispersive OVD, Discovisc (hyaluronic acid 1.6%-chondroitin sulfate 4.0%) was evaluated for comparison. The storage modulus, loss modulus, crossover point, complex viscosity, shear viscosity, and pseudoplasticity were studied. RESULTS The rheological properties of the mixed solution (1:1 and 3:1) showed intermediate characteristics in comparison with the 2 original substances, characterized by a viscosity comparable to that of the superviscous cohesive OVD, but at a higher shear rate (similar to the medium-viscosity dispersive OVD). The new viscous dispersive OVD performed similarly to the medium-viscosity dispersive OVD at low shear rates but was comparable to the superviscous cohesive OVD at high shear rates. CONCLUSIONS The mixture of dispersive and cohesive rheological properties in a single OVD might be an advantage during cataract surgery.

Book Review / Announcement

This second edition gives a very nice overview of the embryogenesis, organogenesis and differentiation of the eye and its adnexa. Ophthalmologists, pediatrics as well as students will make a large profit from this compendium. The early development of the anatomic structures is extremely well illustrated, newly acquired information from research is included. The reference sources are rich and also enable researchers a far-reaching survey. M. Lüchtenberger, Frankfurt