Results-There were 18 eyes in each group. Baseline characteristics were similar in both groups. In the SLT group the mean IOP at baseline, 1, 3, and 6 months was 22.8 (SD 3.0), 20.1 (4.6), 19.3 (6.0), and 17.8 (4.8) mm Hg, respectively. In the ALT group, the mean IOP at baseline, 1, 3, and 6 months was 22.5 (3.6), 19.5 (4.7), 19.6 (5.6), and 17.7 (3.3) mm Hg, respectively. There was a greater anterior chamber reaction, 1 hour after SLT v ALT (p< 0.01). Patients with previous failed ALT had a better reduction in IOP with SLT than with repeat ALT (6.8 (2.4) v 3.6 (1.8) mm Hg; p = 0.01).Conclusion-SLT appears to be equivalent to ALT in lowering IOP during the first 6 months after treatment. There is a slightly greater anterior chamber reaction 1 hour after SLT. Patients with previous failed ALT had a significantly greater drop in IOP when treated with SLT v ALT. These results need to be confirmed with a larger sample size. (Br J Ophthalmol 1999;83:718-722) Argon laser trabeculoplasty (ALT) has become the standard method of treatment for medically uncontrolled open angle glaucoma in North America.1 2 It has been in use since 1979 when it was first described by Wise and Witter. 3 Argon laser ( = 488-514 nm) improves the outflow of aqueous by photocoagulation of the trabecular meshwork (TM). A number of theories have been proposed to explain this eVect of ALT on aqueous outflow. The most widely accepted are the mechanical and cellular theories. According to the mechanical theory, ALT causes coagulative damage to the trabecular meshwork, which results in collagen shrinkage and subsequent scarring of the TM. This tightens the meshwork in the area of each burn and reopens the adjacent, untreated intertrabecular spaces.2-4 The cellular theory proposes that in response to coagulative necrosis induced by the laser, there is migration of macrophages, which phagocytose debris and thus clear the TM. DiVerent types of lasers with various wavelengths are being investigated for laser trabeculoplasty. Recently, a Q switched, frequency doubled Nd:YAG laser ( = 532 nm) has been described for use in trabeculoplasty 5-7 (Mark A Latina, presented at AAO Annual Meeting, San Francisco, 1997). In tissue cultures, it has been demonstrated that the low power and short duration of this laser can selectively target pigmented TM cells while sparing adjacent cells and tissues from collateral thermal damage and can thus maintain the architecture of the TM.8 This procedure has thus been termed selective laser trabeculoplasty (SLT).The objective of our study was to compare the eYcacy of SLT and ALT in lowering the intraocular pressure (IOP) in patients with open angle glaucoma in a prospective randomised clinical trial. Patients and methodsA prospective randomised clinical trial was approved by the research ethics board of Ottawa Hospital. The patients included in this trial were those referred to the glaucoma clinic at the University of Ottawa Eye Institute. Patients were included if they had open angle glaucoma (to increase the generali...

Pseudoexfoliation (PEX) syndrome is the commonest identifiable cause of open-angle glaucoma worldwide. PEX is characterized clinically by small whitish deposits of fibrillar-granular material in the anterior segment of the eye. Despite its prevalence and potential for ophthalmic morbidity, surprisingly little is known about the etiology and pathogenesis of PEX. This article reviews the literature and presents evidence regarding genetic and nongenetic arguments for the etiology of pseudoexfoliation. Lines of evidence that support a genetic basis for PEX include transmission in two-generation families, twin studies, an increased risk of PEX in relatives of affected patients, and HLA studies. Nearly all pedigrees in the literature, and our own experience with PEX families in Iceland and Canada, suggest maternal transmission, raising the possibilities of mitochondrial inheritance, X-linked inheritance, and autosomal inheritance with genomic imprinting. A number of nongenetic factors have also been evaluated for their possible implication in the development of PEX. These include ultraviolet light, autoimmunity, slow virus infection, and trauma. It is possible that a combination of genetic and nongenetic factors may be involved in the etiology and pathogenesis of PEX, i.e. it may be a multifactorial disorder. Further studies with larger numbers of patients are needed to delineate more clearly the contribution of genetic (nuclear DNA, mitochondrial DNA or both) and nongenetic factors to the development of pseudoexfoliation syndrome and pseudoexfoliation glaucoma.

A compensatory effect of increased anterior corneal aberrations by internal aberrations in keratoconic eyes was present for some aberrations. The origin of this compensation and the optical mechanism behind it requires further study.

Purpose: To report refractive outcomes of hyperopic LASIK with automated centration on the visual axis compared with centration on the line of sight (LOS). Methods: The NIDEK Advanced Vision Excimer Laser platform (NAVEX) was used to treat 181 hyperopic eyes with centration on the LOS (LOS group) and 64 hyperopic eyes with centration on the visual axis (visual axis group). The coordinates of the visual axis were digitally transferred to the excimer laser system based on the positional relationship between the LOS and the coaxially sighted corneal light reflex. All eyes were treated with a 6.5-mm optical zone and 9.0-mm transition zone. Three-month postoperative outcomes were retrospectively analyzed. Results: The preoperative manifest refraction spherical equivalent (MRSE) was +2.57±1.26 diopters (D) (range: 0.13 to 5.63 D) in the visual axis group and +2.46±1.32 D (range: 0.38 to 5.63 D) in the LOS group. The postoperative MRSE was +0.29±0.70 D (range: −1.00 to 1.75 D) in the visual axis group and +0.19±0.57 D (range: −0.75 to 1.75 D) in the LOS group. Postoperatively, 81% (38/47) of eyes in the visual axis group and 64% (74/116) of eyes in the LOS group were ±0.50 D. In the visual axis group, 91% (44/52) of eyes and 92% (102/109) of eyes in the LOS group maintained best spectacle-corrected visual acuity within one line compared with preoperatively. Conclusions: Initial experience with hyperopic LASIK centered on the visual axis indicated safe and predictable outcomes. [ J Refract Surg . 2009;25:S98–S103.]