Intrascleral anchoring knot on the double suture without peritomy for fixation of intraocular lens.

A new minimally invasive technique for universal fixation of any posterior chamber intraocular lens (IOL), iris prosthesis or capsular tension device (CTD), both for rescuing in case of dislocation and for secondary implantation, is described. It uses intrascleral anchoring knot on the reinforced double 9-0 polypropylene suture without conjunctival opening or scleral dissection. The technique was applied for scleral fixation of the S-shaped monoblock acrylic IOL dislocated into the vitreous cavity in 1 eye, and decentered IOL-CTD-capsular bag complexes in 3 eyes. In none of the cases, complications including knot slippage, suture exposure or hypotony were observed. All patients were followed up for 6 months. The uncorrected distance visual acuity was significantly improved and the IOLs positions remained stable. The described technique might be a simple, effective and safe alternative to flanged scleral fixation approaches.

Interaction between topographic/tomographic parameters and dry eye disease in keratoconus patients.

PURPOSE: To determine the interaction between corneal topographic and tomographic parameters and dry eye syndrome (DES) in keratoconus (KC) patients. METHODS: Seventy-seven eyes of 49 patients with KC (age 34.4 ± 11.6 years) were enrolled in this study. In these 77 eyes we recorded surface regularity index (SRI), surface asymmetry index (SAI) and Klyce/Maeda KC index (KCI) using the Topographic Modeling System (TMS-5, Tomey, Tennenlohe, Germany), Index of Surface Variance (ISV), Index of Vertical Asymmetry (IVA), KC Index (KI), Center KC Index (CKI), Index of Height Asymmetry (IHA) and Index of Height Decentration (IHD) using Pentacam (Pentacam HR, Oculus, Germany). Patients were subdivided into mild (grade 1-2) and severe stage (grade 3-4) KC groups according to Pentacam grading. To analyse tear film parameters we assessed in 77 KC eyes McMonnies questionnaire, Schirmer test and break-up time and in 26 eyes (10 eyes with mild KC, 16 eyes with severe KC) high-speed videokeratoscopy (during interblinking interval) using a novel commercially not available system (Tear Inspect). With Tear Inspect the analysed tear film parameters were (1) time of first irregularities of Placido rings and (2) time of eyelid closure. Patients were also subdivided into McMonnies questionnaire positive and negative groups. RESULTS: We did not find significant difference between patients with mild and severe KC in any of the examined tear film parameters (p > 0.66). There was no significant difference in SRI, SAI, KCI, ISV, IVA, KI, CKI, IHA and IHD in McMonnies test positive and negative KC patients (p > 0.07). There was no correlation between SRI, SAI, KCI, ISV, IVA, KI, CKI, IHA and IHD and any of the examined tear film parameters (without high-speed videokeratoscopy) neither in 77 KC patients nor in mild or severe KC eyes (r < 0.3). CONCLUSIONS: There is no interaction between DES and topographic/tomographic changes in KC-patients.

Experimental femtosecond laser-assisted nanosurgery of anterior lens capsule.

PURPOSE: To investigate femtosecond laser-assisted nanosurgery of the anterior lens capsule in a prospective in vitro study. METHODS: Eight anterior lens capsules obtained during conventional phaco surgery were irradiated with a nonamplified 80-MHz near-infrared 800-nm titanium:sapphire femtosecond laser. Line intratissue laser cuts were examined by femtosecond multiphoton laser scanning microscopy (MLSM) and transmission electron microscopy (TEM). RESULTS: Speed parameters of the laser beam, laser ablation time, and pulse power determined the width of the lesions, which ranged from 220±40 nm (SD) to 1.49±0.15 µm. Both MLSM and TEM revealed minimal collateral alterations in the tissue surrounding the laser cuts. CONCLUSIONS: Nonamplified near-infrared femtosecond laser pulses at low pulse energies may be a promising strategy for precise noncontact nanosurgery of the anterior lens capsule with minimal collateral damage to surrounding tissue. High-resolution MLSM offers 3-dimensional, noninvasive, nondestructive imaging at submicrometer resolution within seconds before and after ablation.

In vitro femtosecond laser-assisted nanosurgery of porcine posterior capsule.

PURPOSE: To investigate femtosecond laser-assisted nanosurgery of the posterior capsule in a prospective in vitro animal study. SETTING: Department of Ophthalmology and Eye Hospital, University of Saarland, Homburg, and Fraunhofer Institute for Biomedical Engineering, St. Ingbert, Germany. METHODS: The posterior capsules of 12 porcine eyes were irradiated with a nonamplified 90 MHz near-infrared 750 nm titanium:sapphire femtosecond laser. Intratissue and superficial laser cuts of laser-ablated (5 capsules) and control (1 capsule) specimens were examined by femtosecond multiphoton laser scanning microscopy (MLSM) and transmission electron microscopy (TEM). RESULTS: Laser exposure time and pulse power determined the width of the lesions, which ranged from 0.69 microm+/-0.19 (SD) to 2.81+/-0.5 microm. Both MLSM and TEM revealed minimal collateral alterations in the tissue surrounding the laser cuts. CONCLUSIONS: Nonamplified near-infrared femtosecond laser pulses at low pulse energies may be a promising strategy for precise lamellar noncontact nanosurgery of the posterior capsule, with minimal structural collateral damage to surrounding tissue. High-resolution MLSM offers 3-dimensional, noninvasive, nondestructive imaging at submicrometer resolution within seconds before and after ablation.

Femtosecond laser-assisted retinal imaging and ablation: experimental pilot study.

PURPOSE: To investigate retinal imaging and ablation using femtosecond laser pulses. MATERIALS AND METHODS: Two non-amplified near-infrared femtosecond lasers were used to irradiate porcine retinal specimens in vitro. The lasers were used for tissue removal as well as multiphoton laser scanning microscopy. RESULTS: Ablation of the nerve fiber layer was performed at pulse energies of 1.0 nJ to 3.9 nJ. Control laser scanning images were acquired within seconds after irradiation. Specimens were additionally investigated with electron microscopy. CONCLUSIONS: Non-amplified femtosecond lasers may allow precise surgery controlled by fast high-resolution imaging of the target.

In vitro noncontact intravascular femtosecond laser surgery in models of branch retinal vein occlusion.

PURPOSE: To investigate intravenous femtosecond laser surgery in models of branch retinal vein occlusion. MATERIALS AND METHODS: Non-amplified near infrared femtosecond laser was used to ablate polyamide sutures and human hairs inserted into the vascular lumina of porcine retinal veins in vitro. Specimens were subjected to multiphoton laser scanning microscopy and electron microscopy. RESULTS: Regular laser cuts within sutures and hairs were detected with laser microscopy and electron microscopy. Neither laser microscopy nor histology revealed collateral damage of the vascular wall. CONCLUSIONS: Non-amplified femtosecond lasers may allow precise atraumatic non-contact intravenous retinal surgery controlled by high-resolution imaging of the target.