Efficacy of SLO-Microperimetry and Humphrey for evaluating macular sensitivity changes in advanced glaucoma.

OBJECTIVE: To compare the efficacy of scanning laser ophthalmoscope microperimetry (SLO-MP) and Humphrey visual fields in detecting macular sensitivity changes in advanced glaucoma. DESIGN: Prospective cohort study. PARTICIPANTS: 25 patients with advanced primary open angle glaucoma and 2 consecutive abnormal Humphrey 10-2 SITA Standard visual field tests. METHODS: Thirty-six eyes of 25 patients with 2 consecutive abnormal Humphrey 10-2 SITA Standard (H10) visual fields were retested with a modified 10-2 SLO-MP within 3 months of the last reliable H10. A standardized grid was used to mark the macula. Primary outcome was change in mean macular sensitivity (dB; H10 and SLO-MP) in relation to mean macular retinal nerve fibre layer (RNFL) thickness (µm) by SLO- optical coherence tomography (SLO-OCT). Secondary outcome was comparison of reliability indices for both tests. Linear regression was used for analysis. RESULTS: Mean macular sensitivity was significantly lower in SLO-MP (9.33 ± 3.37 dB) than H10 (18.83 ± 6.46 dB; p < 0.0001). Mean macular RNFL thickness correlated significantly with retinal sensitivity by both SLO-MP (r = 0.39, p < 0.02) and H10 (r = 0.37, p < 0.03). Fixation losses were better controlled in SLO-MP (0.38 ± 1.1) than H10 (4.28 ± 7.9; p = 0.008). False-positive responses were similar (SLO-MP: 2.25 ± 4.53, H10: 1.78 ± 3.33; p = 0.80). A statistically significant difference was noted in the false-negative responses (SLO-MP: 26.87 ± 25.24, H10: 5.33 ± 9.70; p < 0.0001). CONCLUSIONS: Macular sensitivity determined by both H10 and SLO-MP correlates significantly with mean macular RNFL thickness measured by SLO-OCT. Precise localization of the macula in SLO-MP results in lower fixation losses. Detection of denser field defects by SLO-MP results in higher false-negative responses. A larger sample size is needed to further study the value of this diagnostic tool.

Long-term visual and refractive outcomes following surface ablation techniques in a large population for myopia correction.

PURPOSE: To evaluate the visual and refractive outcome for four wavefront-guided surface ablation (WGSA) techniques (LASEK, LASEK flap-off [LASEK FO], Epi-LASIK, and Epi-LASIK flap-off [Epi-LASIK FO]) in a large myopic population. METHODS: This retrospective review included 1000 myopic eyes (spherical equivalent [SE] -1.0 to -8.0 diopters [D]) treated with WGSA (VISX STAR S4 with IR) using four different epithelial management techniques. Flaps were either retained (163 Epi-LASIK, 361 LASEK) or discarded (277 Epi-LASIK FO, 199 LASEK FO). Eyes in each group were stratified to either low, mild, moderate, or high myopia based on preoperative SE. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), predictability, lines lost, and haze were compared at 3, 6, and 12 months. RESULTS: At 1 year, UDVA and CDVA of ≥20/20 and 20/15 were comparable across the four procedure groups and within each subgroup of myopia. Predictability was less than or equal to ±0.5 D of intended correction in 96% to 99% of eyes. LASEK FO and Epi-LASIK FO outperformed the EPI-LASIK in achieved MRSE, especially in the high myopia category (-0.012, 0.040, and -0.27 D, respectively, P < 0.05). No eyes lost more than one line of CDVA; and 50% to 60% of eyes in each group gained one or more lines. No significant haze was recorded in any group. There was no statistically significant difference between groups in the preoperative MRSE and efficacy indices except for LASEK FO. CONCLUSIONS: At 1 year, there was no statistically significant difference in visual outcomes between techniques for any degree of myopia. However, the MRSE achieved with LASEK FO and Epi-LASIK FO were closer to emmetropia.

Endoscopic goniotomy: early clinical experience in congenital glaucoma.

PURPOSE: To review the technique and early outcomes of endoscopic goniotomy (EG) in children with opaque corneas and primary congenital glaucoma (PCG) or developmental glaucoma with ocular or systemic anomalies (DG). METHODS: EG was performed for approximately 300 degrees of the angle through temporal and superonasal corneal incisions. We retrospectively reviewed consecutive cases from 2003 to 2007. Primary outcome was intraocular pressure (IOP) change from baseline to last postoperative visit. Success was defined as IOP < or=21 mm Hg with or without medication but no further surgical intervention. RESULTS: Fourteen eyes of 8 patients (4 PCG, 4 DG) were included. Mean age at surgery was 3.88+/-3.72 months. The reduction in IOP from baseline to the last follow-up visit was -16.7+/-16.7 mm Hg. Success was achieved in 6 of the 16 eyes (Total=43%, PCG=50%, DG=30%). Corneal diameter and axial length remained stable in all eyes. Two patients with DG needed additional surgery after 8 to 9 months. Complications included cataract and zonular dialysis both in 2 patients with aniridia. CONCLUSIONS: This pilot study indicates that EG shows reasonable potential for IOP control in congenital glaucoma. The safety and efficacy of EG needs to be further studied with a larger sample size and comparison to other angle surgery techniques.

Biometric characteristics of eyes with exfoliation syndrome and occludable as well as open angles and eyes with primary open-angle glaucoma.

OBJECTIVE: To describe differences in axial length scan (A-scan) and ultrasound biomicroscopy (UBM) parameters in eyes with exfoliation syndrome (XFS) and occludable angles (XFSOc), XFS and open angles (XFSOp), and eyes with primary open-angle glaucoma (POAG). DESIGN: Cross-sectional descriptive study. PARTICIPANTS: Seventy-two eyes of 72 patients (mostly Caucasians) were identified through glaucoma clinics at the University of Ottawa;19 eyes had XFSOc, 31 eyes XFSOp, and 22 eyes POAG. METHODS: After a detailed ophthalmic history and examination, A-scan biometry and UBM were done to assess anterior segment parameters: central anterior chamber depth (ACD), lens thickness, trabecular meshwork-iris angle, and angle opening distance (AOD). Lens/axial length factor and the relative lens position were calculated. The above measurements were compared across the 3 groups. RESULTS: We found statistically significant differences in measurements among the groups. ACD was shallowest in eyes with XFSOc (1.88 [SD 0.07] mm), followed by XFSOp (2.37 [SD 0.05] mm), and POAG (2.64 [SD 0.08] mm). XFSOc had thicker lenses (5.28 [SD 0.09] mm) compared with the other groups: XFSOp (5.03 [SD 0.06] mm) and POAG (4.84 [SD 0.09] mm). Lens/axial length factor was highest in XFSOc (2.34 [SD 0.05] mm) versus XFSOp (2.12 [SD 0.03] mm) and POAG (2.02 [SD 0.05] mm); relative lens position was lowest in XFSOc (2.27 [SD 0.03] mm) versus XFSOp (2.31 [SD 0.02] mm) and POAG (2.36 [SD 0.03] mm). CONCLUSIONS: Eyes with XFSOc in our study demonstrated lens thickening and shallow central ACD versus eyes with XFSOp and eyes with POAG. This suggests the possibility that cataract formation and (or) zonular weakness may contribute to the development of an occludable angle in eyes with XFS.

Ultrasound biomicroscopy characterization of acrylic, silicone, and polymethyl methacrylate lenses in vitro.

BACKGROUND: This study aims to characterize the reflective properties of some commonly used intraocular lenses (IOLs) in vitro, with a particular focus on lens haptics. METHODS: Six different types of IOLs, representative of silicone, acrylic, and polymethyl methacrylate (PMMA), single, multipiece, and multifocal were imaged using high-resolution ultrasound biomicroscopy (UBM). RESULTS: Reflectivity patterns were distinct to the material that was being imaged irrespective of whether the part being imaged was the haptic or optic. Acrylic haptics demonstrated a single "tram-track" reduplication echo, whereas PMMA haptics showed multiple reverberation echoes off the posterior surface. The optics of various PMMA and acrylic lenses demonstrated a reflectivity pattern similar to the respective haptics made of the same material. Silicone optics displayed clear delineation with no reverberation. Both acrylic and silicone material was relatively less reflective when compared with PMMA. INTERPRETATION: With UBM imaging, the haptics of acrylic and PMMA IOLs demonstrate unique reflective patterns, depending on the material being studied. Prior knowledge of what the lens haptics and optics look like in vitro provides information that may assist in identifying and localizing misplaced intraocular lenses in vivo.

Medical management of primary open-angle glaucoma: Best practices associated with enhanced patient compliance and persistency.

Primary open angle glaucoma is a chronic optic neuropathy often requiring lifelong treatment. Patient compliance, adherence and persistence with therapy play a vital role in improved outcomes by reducing morbidity and the economic consequences that are associated with disease progression. A literature review including searches of The Cochrane Library, MEDLINE, PubMed, conference proceedings, and bibliographies of identified articles reveals the enormous public health burden in various populations due to the impact of glaucoma associated visual impairment on the overall quality of life eg, fear of blindness, inability to work in certain occupations, driving restrictions, motor vehicle accidents, falls, and general health status. Providing specific definitions for the frequently misunderstood terms "compliance, persistence and adherence" with reference to medication use is central not only for monitoring patients' drug dosing histories and clinical outcomes but also for subsequent research. In this review article, a summary of the advantages/disadvantages including cost-effectiveness of various medical approaches to glaucoma treatment, techniques employed for measuring patient compliance and actual patient preferences for therapy are outlined. We conclude by identifying the key barriers to ongoing treatment and suggest some best practices to enhance compliance and persistence.