Giorgia Sanguinetti

Glistenings in foldable intraocular lenses

Purpose: To evaluate the formation of glistenings in foldable intraocular lenses (IOLs) of various materials after cataract surgery. Setting: University Eye Clinic of Trieste, Trieste, Italy. Methods: In this prospective study, 273 patients were randomized to have implantation of 1 of 7 types of foldable IOLs in the capsular bag after phacoemulsification. The IOLs were the CeeOn® Edge 911A (Pharmacia & Upjohn Co.), ACR6D® (Corneal), AcrySof® (Alcon), SI‐40NB (AMO), Hydroview® H60M (Storz), Sensar® (AMO), and Stabibag® (Ioltech). The presence of glistenings in the IOL optic was assessed by slitlamp evaluation 7, 30, 90, 180, 360, and 720 days after surgery. The glistenings were graded at each control. Results: Glistenings were observed in all IOL groups. The percentage of patients with glistenings ranged from 40.0% to 67.5%, with the percentage increasing up to 90 days after surgery and then becoming stable in most groups. The AcrySof group had a continuous increase over time. The mean grade of glistenings increased up to 180 days after surgery and then became stable in most groups. The AcrySof and 911A groups had a continuous increase over time. Conclusions: Glistening formation was observed in 7 different foldable IOLs. The AcrySof group had a higher percentage and a greater density of glistenings.

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.

Visualization of fluid turbulence and acoustic cavitation during phacoemulsification

Purpose: To describe a technique for visualizing fluid turbulence and cavitational energy created by ultrasonic phaco tips. Setting: University Eye Clinic of Trieste, Trieste, Italy. Methods: Generation of cavitational energy by the phaco tip was visualized using an optical test bench comprising several components. The technique uses a telescope system to expand a laser light source into a coherent, collimated beam of light with a diameter of approximately 50.0 mm. The expanded laser beam shines on the test tube containing the tip activated in a medium of water or ophthalmic viscosurgical device (OVD). Two precision optical collimators complete the optical test bench and form the system used to focus data onto a charge‐coupled device television camera connected to a recorder. Results: Images of irrigation, irrigation combined with aspiration, irrigation/aspiration, and phacosonication were obtained with the tip immersed in a tube containing water or OVD. Conclusions: Optical image processing enabled acoustic cavitation to be visualized during phacosonication. The system is a possible means of evaluating a single phaco apparatus power setting and comparing phaco machines and techniques.

Tissue reaction to hydrophilic intraocular lenses

The implant of intraocular lenses (IOLs) following cataract surgery induces a foreign body reaction to the IOL and a lens epithelial cell reaction. The host response to the IOL is mainly influenced by biomaterial properties. With the increasing use of phacoemulsification and small incision cataract surgery, there is growing interest in the use of foldable IOLs made of different materials. Hydrophilic acrylic IOLs include a wide group of foldable biomaterials different in terms of water content. These lenses have been reported to show a good biocompatibility after implantation. Nevertheless, tissue reaction to the implant of hydrophilic lenses is variable and not directly related to the hydrophilicity of their surface. A different adsorption of proteins on the IOL optic surface might be responsible for the different cellular reaction and lens epithelial cell response. Other properties besides hydrophilicity should be taken into account to classify IOL biomaterials.

Clinical and angiographic features in nasal branch retinal vein occlusion

Purpose: To analyse the epidemiological and clinical characteristics of nasal branch retinal vein occlusion (NBRVO). Methods: Patients affected by branch retinal vein occlusion observed in the out-patient departments of the Eye Clinic of Trieste between January 1995 and January 1999 were enrolled. Results: Out of 144 patients with branch retinal vein occlusion, 128 (88.9%) were affected by temporal branch retinal vein occlusion (TBRVO), and 16 patients were affected by NBRVO (11.1%). The two groups did not differ as far as systemic hypertension, diabetes mellitus, glaucoma and ischaemic heart disease were regarded. NBRVO cases were characterized by better visual acuity and greater figures of capillary non-perfusion, retinal neovascularization and vitreous haemorrhage. Conclusions: NBRVO, even though infrequent, shares the same epidemiological characteristics as TBRVO. The higher prevalence of ischaemic cases in the NBRVO group could depend on a bias during the enrolment of patients, because especially symptomatic patients may have been examined in our out-patient departments. The relatively high percentage of epiretinal membrane formation after laser photocoagulation suggests particular caution, especially in cases presenting with vitreous haemorrhage.

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.

Schlieren visualization of fluid dynamics phenomena during phacosonication in cataract surgery

In ultrasonic phacoemulsification during cataract surgery the lens material fragmentation has been described as being caused by a combination of several mechanisms. The different theories involve tip vibration, acoustic waves produced by the tip, particles and liquids impact on the surface of the lens and cavitation. However the mechanisms are still not clear. To better understand phaco-related phenomena we have tried to produce a description in term of images of the cataract phacoemulsification procedure. An expanded and collimated laser diode beam transilluminates a transparent tube containing a liquid medium. The machine is activated separating the different phases of irrigation, aspiration and phacosonication. Fluid turbulences and phenomena related to the tip vibration constitute the phase images, visualized using Schlieren or similar techniques. The optical Fourier transform is filtered by a blade or by a black dot. The filtered transform is reconstructed into the visualized phase image and this is acquired by a digital image processing system. The presence of acoustic cavitation and possibly of ultrasonic radiation has been revealed. The technique promises to be a possible means for evaluation of single phaco apparatus power setting and comparison between different machines in terms of power modulation and cavitation production.