Automated Direct Selective Laser Trabeculoplasty: First Prospective Clinical Trial.

Purpose: Direct selective laser trabeculoplasty (DSLT) is a rapid, noncontact automated procedure performed directly through the limbus without gonioscopy. In this first nonrandomized clinical trial we assessed its safety and ability to reduce intraocular pressure (IOP). Methods: Fifteen patients (15 eyes: 10 with open-angle glaucoma [OAG], 4 with ocular hypertension, and 1 with pseudoexfoliation glaucoma), naive or after medication washout, with an IOP ≥22 mm Hg, underwent DSLT by irradiation with 100 or 120 sequential noncontact 532-nm, Q-switched laser shots (0.8-1.4 mJ) automatically applied during 1.5 or 2.3 seconds on the limbus, guided by image analysis and eye tracking. Results were assessed at 1 and 3 hours, 1 day, 1 week, and 1, 3, and 6 months. Results: The mean ± standard deviation baseline IOP (mm Hg) in all eyes was 26.7 ± 2.3. At 1, 3, and 6 months, this value was significantly reduced to 21.7 ± 4.2 (by 18.1%), to 20.8 ± 2.5 (by 21.4%), and to 21.5 ± 4.1 (by 18.8%), respectively. In six patients treated with 1.4 mJ/shot, the mean IOP at 6 months decreased from 26.7 ± 3.2 to 19.3 ± 2.0 (27.1%, P = 0.03). There was a significant reduction in hypotensive medications (from 1.6 ± 1.0 to 0.4 ± 0.7, P = 0.03). No serious adverse events occurred. Conclusions: Automated DSLT appears to be an effective and safe noncontact, rapid modality for reducing IOP in patients with OAG. Higher energy usage led to better results. Translational Relevance: Studying laser transmission through sclera enabled laser irradiation of the trabeculum without gonioscopy.

Non-contact direct selective laser trabeculoplasty: light propagation analysis.

Selective laser trabeculoplasty (SLT), used to treat glaucoma and ocular hypertension, requires the use of a gonioscope placed on the cornea to visualize and irradiate the trabecular meshwork (TM). Alternatively, non-contact direct SLT (DSLT) irradiates the TM through the overlying tissues. Here we analyze this innovative procedure using analytical modeling and Monte Carlo simulations to quantify the laser energy reaching the TM through the overlying tissues. Compared with energy launched from the laser, DSLT energy transmission to the TM is 2.8 times less than SLT, which verifies the efficacy of non-contact DSLT given the lowest reported effective SLT energies.

Intraocular pressure measurements and biomechanical properties of the cornea in eyes after penetrating keratoplasty.

PURPOSE: To compare intraocular pressure (IOP) measurements obtained using the Goldmann applanation tonometer (GAT; Haag-Streit), the Tono-Pen XL (Reichert, Inc), and the ocular response analyzer (ORA; Reichert Ophthalmic Instruments), and to determine the influence of corneal factors on IOP measurements in eyes that had undergone penetrating keratoplasty (PK). DESIGN: Consecutive, prospective study. METHODS: Study population. Sixty-one eyes that underwent PK were enrolled in this study. Intervention. IOP was measured using the GAT, Tono-Pen, and ORA. Corneal hysteresis and corneal resistance factor as provided by the ORA were recorded. Central corneal thickness was measured using an ultrasound pachymeter. Main outcome measures. IOP and corneal biomechanical factors. RESULTS: IOP measurements were obtained in an average of 65 months (range, 6 to 209 months) after PK surgery. ORA-derived IOP measurements (corneal-compensated IOP and Goldmann-correlated IOP) and Tono-Pen XL IOP all correlated in a significant manner to GAT IOP measurements. Corneal-compensated IOP and Tono-Pen XL IOP values were higher than GAT IOP (P < .001 and P = .001, respectively), whereas Goldmann-correlated IOP readings did not differ from GAT IOP readings (P = .054). Central corneal thickness did not correlate to any tonometry technique. In a regression analysis, corneal hysteresis and corneal resistance factor were found to play a role in IOP prediction. CONCLUSIONS: Central corneal thickness may be of less importance than corneal hysteresis and corneal resistance factor in IOP determination in eyes that have undergone PK, perhaps because of the lower modulus of elasticity in these eyes. GAT IOP seems to be lower than other tonometry techniques in eyes that have undergone PK.

Scanning laser Doppler flowmetry of nonperfused regions of the optic nerve head in patients with glaucoma.

BACKGROUND AND OBJECTIVE: To examine the reliability of scanning laser Doppler flowmetry in measuring capillary flow in regions of the optic nerve head, which are manifested differently by confocal tomographic angiography. PATIENTS AND METHODS: Capillary blood flow of the optic nerve head was measured in 16 eyes of 13 patients who had glaucoma with moderate to severe visual field defects. Blood flow measurements were taken by the scanning laser Doppler flowmeter and analyzed using the automatic full-field perfusion image analyzer (AFFPIA). Flow values were compared between perfused and nonperfused halves of the optic nerve head. Vascular anatomy of the optic nerve head was evaluated by confocal laser tomography with indocyanine green injection, and visual field tests by a standard visual field analyzer. RESULTS: Analysis of laser capillary flow parameters by the AFFPIA disclosed a mean lower flow value in nonperfused compared with perfused discs (426 +/- 310 vs 547 +/- 306; P = .006). There was also a positive correlation between visual field defect and capillary angiography of the optic nerve head. CONCLUSIONS: Flow measurements of the optic nerve head by scanning laser Doppler flowmetry using the AFFPIA revealed a mean lower flow value in nonperfused discs of patients who had glaucoma with severe visual field defect. Capillary angiography demonstrated by Heidelberg retina angiography has a good correlation with the pattern of visual field defect.