In vivo corneal confocal microscopy in marfan syndrome.

PURPOSE: To examine the cornea of patients with Marfan syndrome in comparison with a control group by using the in vivo confocal microscope. METHODS: Twenty-four eyes of 12 patients with Marfan syndrome had their corneas examined using the in vivo confocal microscope Heidelberg Retina Tomograph (HRT) II/Rostock Cornea Module. The control group included 24 eyes of 12 subjects who had their corneas examined by the same in vivo confocal microscope. RESULTS: Epithelium and neural plexus examination did not show any difference between the 2 groups. Examination of the stroma showed no significant differences concerning the morphology and density of keratocytes. The extracellular matrix of 16 of the 24 eyes of the Marfan group was clearly visible and showed thin highly reflective interconnected lines between keratocytes. In the healthy eye group, reflective lines were observed in only 5 of the 24 eyes. The endothelium of 14 corneas of the Marfan group showed brightly reflective particles. In no cornea of the control group were such particles observed. CONCLUSIONS: Highly reflective extracellular matrix of the stroma and brightly reflective particles among the endothelial cells were the 2 main corneal findings observed by using in vivo corneal confocal microscopy in patients with Marfan syndrome compared with a control group. Further studies need to be made to confirm these findings and eventually find new criteria for Marfan syndrome from the examination of in vivo corneal confocal microscopy.

In vivo corneal confocal microscopy comparison of intralase femtosecond laser and mechanical microkeratome for laser in situ keratomileusis.

PURPOSE: To assess and compare corneal modifications induced by IntraLase PulsionFS femtosecond laser and mechanical microkeratome Hansatome for laser in situ keratomileusis (LASIK) using the new-generation Heidelberg Retina Tomograph II (HRT II)/Rostock Cornea Module confocal microscope. METHODS: In this case-control study, 24 eyes of 12 patients were examined with the HRT II in the follow-up of IntraLase femtosecond laser for LASIK myopic surgery. Twenty eyes of 10 patients were also examined after microkeratome Hansatome-LASIK surgery. In both groups, the patients underwent the first follow-up examination on day 7 and the last 12 months after surgery. Morphologic modifications of corneal architecture were evaluated, and comparisons were made between the two flap-formation techniques. RESULTS: Evaluation of both groups on day 7 showed keratocyte transformation, most likely related to cellular activation beneath the interface. The flap margin after the IntraLase technique appeared microscopically as a clear-cut edge that included the epithelial plug. At month 2, secondary fibrosis, adjacent to the still well-defined IntraLase flap edge, was observed. This reaction diminished with time, leaving a fibrotic scar adjacent to a wound constriction originating from the surrounding stroma. The flap margin of the mechanical microkeratome had the appearance of a less clearly identified fibrotic scar with no epithelial plug. CONCLUSIONS: This study reveals morphologic similarities between the interfaces obtained by femtosecond laser and mechanical microkeratome, probably because the same excimer laser performed the photoablation. However, the IntraLase flap margin showed greater fibrotic scarring than that induced by the mechanical microkeratome.

Porous polyethylene orbital implant in the pediatric population.

PURPOSE: To determine the incidence of complications of primary insertion of porous polyethylene orbital implant in the pediatric population. DESIGN: Interventional case series. METHODS: Prospective nonrandomized case series of 36 eyes of 36 patients under age 15 years who underwent primary placement of an anteriorly wrapped spherical porous polyethylene orbital implant from March 1998 to August 2002, with at least 17 months of follow-up. RESULTS: The mean age at the time of surgery was 4.6 years. The histopathologic diagnoses after enucleation included intraocular tumor in 22 patients, phthisis bulbi in eight patients, microphthalmos in three patients, Coats disease in two patients, and ruptured traumatic globe in one patient. Twelve patients (33%) had prior ocular surgery. At the time of enucleation, all patients underwent primary placement of spherical porous polyethylene orbital implant anteriorly wrapped with homologous sclera in 30 patients (83%) and autologous sclera in six patients (17%). The spherical implant size was 16 mm in one patient (3%), 18 mm in 10 patients ( 28%), and 20 mm in 25 patients (69%). The prosthesis was fitted after a mean interval of 5 weeks. After a mean follow-up of 44 months (range, 17 to 68 months), there was one case of pyogenic granuloma (3%) and one case of implant exposure (3%). There were no cases of implant extrusion, superior sulcus syndrome, orbital cellulitis, or significant inflammatory response. No porous polyethylene orbital implant was drilled for peg placement. CONCLUSIONS: Anteriorly wrapped primary porous polyethylene orbital implant in the pediatric population appears to be well tolerated with few complications.

Choroidal ischemia secondary to a diving injury.

PURPOSE: To report a case of choroidal ischemia in a professional diver after a decompression sickness accident. METHODS: A 31-year-old man presented a decompression sickness accident without any systemic manifestation. The symptoms were exclusively ophthalmic with sudden decrease of vision and presence of scotoma predominantly on the left eye immediately after a dive. The patient had a complete clinical ophthalmologic examination as well as fluorescein angiography, optical coherence tomography, central visual field, visual-evoked potentials, and electroretinogram examinations that were repeated during the follow-up over a period of 18 months. RESULTS: The examinations performed 1 week after the decompression sickness accident and the hyperbaric oxygen therapy showed diminution of foveal reflectivity associated with retinal pigment epithelium modifications, deficit of choroidal perfusion in the macular region, and important central scotoma in both eyes. During the follow-up, the central scotoma disappeared after 6 months. The retinal pigment epithelium presented pigmentary migrations without subretinal fluid accumulation. CONCLUSION: This case report describes choroidal ischemia resulting from decompression-induced intravascular gaseous microemboli caused by a decompression sickness diving accident.

Modifications in corneal biomechanics and intraocular pressure after deep sclerectomy.

PURPOSE: To compare preoperative and postoperative measurements of corneal biomechanical properties and intraocular pressure (IOP) using Goldmann applanation tonometry (GAT) and the ocular response analyzer (ORA) in eyes undergoing deep sclerectomy with collagen implant (DSCI). PATIENTS AND METHODS: Thirty eyes of 30 glaucomatous patients undergoing deep sclerectomy with collagen implant and 30 eyes of 30 normal subjects were included. Goldmann applanation IOP, central corneal thickness (CCT), and ORA measurements [corneal compensated IOP (IOPcc), Goldmann-correlated IOP (IOPg), corneal resistance factor (CRF), and corneal hysteresis (CH)] were taken the day before deep sclerectomy with collagen implant and on days 1, 8, and 30 after surgery. Preoperative CH values were correlated to the number of preoperative medications and to the CCT. Also, the ORA measurements of normal subjects were compared with the preoperative measurements of the glaucomatous patients. RESULTS: The 30 glaucomatous eyes showed a statistically significant difference between preoperative and day 1 postoperative GAT IOP, ORA IOPcc, IOPg, CRF, and CH measurements. No statistically significant difference was noted when comparing the GAT IOP, ORA IOPcc, IOPg, and CRF measurements between days 1, 8, and 30 after DSCI.On the contrary, CH values were statistically different when comparing days 1, 8, and 30 after DSCI. The 30 normal eyes showed no statistical difference when compared with the preoperative IOPg parameter in the 30 glaucomatous eyes; the mean CRF and the mean CH values were statistically significantly higher than the preoperative values of the glaucomatous group. CONCLUSIONS: CH statistically increased between preoperative and postoperative day 1 DSCI. On days 8 and 30, the change in CH values was statistically significant.

Activity detection and causal interaction analysis among independent EEG components from memory related tasks.

Over the past few years there has been an increased interest in studying the underlying neural mechanism of cognitive brain activity related to memory. In this direction, we study the brain activity based on its independent components instead of the EEG signal itself aiming towards identifying and analyzing induced responses being attributed to oscillatory bursts from local or distant neural assemblies, with variable latency and frequency, in an auditory working memory paradigm. The contribution and functional coupling of independent components to evoked and/or induced oscillatory activities is investigated through the concept of the recently introduced partial directed coherence method, which can also reveal the direction of the statistically significant relationships. The results on read data from an oddball experiment are in accordance with previous psychophysiology studies suggesting increased phase locked activity most prominently in the delta/ theta band, while alpha is also apparent in measures of non phase-locked activity. Dynamic synchronization is inferred between the alpha and delta bands, whereas some influence of the theta band is also detected. This study indicates that functional connectivity during cognitive processes may be successfully assessed using spectral power measures applied on independent components, which reflect distinct spatial patterns of activity.