Long-term Follow-up of Ahmed Glaucoma Valve Tube Position Changes.

PURPOSE: To evaluate long-term (4.5 to 6 y) changes in the position of Ahmed glaucoma valve (AGV) tubes. MATERIALS AND METHODS: Adult patients aged 18 years and above, 1 to 2 months post-AGV implantation were enrolled. Tube position was evaluated using anterior segment optical coherence tomography at baseline and final follow-up. The intracameral tube length (ICL), tube-cornea (TC) distance, and cornea-tube angle were measured. Wilcoxon-signed rank test was used to assess whether the changes in parameters from baseline were significant. RESULTS: In total, 11 eyes of 9 patients were included in the analysis. Mean duration of follow-up was 5.2±0.8 years (4.4 to 6.1 y). The ICL increased from 1.58±0.40 to 1.74±0.62 mm (P=0.18). The TC decreased from 0.36±0.12 to 0.29±0.05 mm (P=0.04). The cornea-tube angle decreased from 27.76±5.57 to 24.82±5.69 degrees (P=0.08). Overall, 73% of the tubes moved toward the cornea (mean 0.11 mm, over 4.4 to 6.1 y). In total, 73% showed an increase in ICL; 45% showed an increase of >0.3 mm [mean 0.50 mm (33%) increase]. Two of 11 tubes (18%) showed no significant change in the parameters (ICL, 0.03 and 0.01 mm increase; TC, 0 and 0.01 mm increase); these tubes were noted to lie on the iris. CONCLUSIONS: Tubes tend to move toward the cornea over time. To avoid corneal damage and involvement of the visual axis in the future, tubes should be reasonably short and inserted tangentially, preferably in the posterior one third of the anterior chamber.

Intraoperative complication rates in cataract surgery performed by ophthalmology resident trainees compared to staff surgeons in a Canadian academic center.

PURPOSE: To compare the intraoperative complication rates in cataract surgery performed by resident trainees and staff ophthalmologists. SETTING: Kensington Eye Institute, University of Toronto, Toronto, Canada. DESIGN: Prospective case series. METHODS: This study included 8738 consecutive cases of primary phacoemulsification cataract surgery performed by staff surgeons and resident trainees from January to December 2016. There were no exclusion criteria. Data collected included the level of resident training, case complexity, degree of resident involvement, and intraoperative complications. Primary outcome measures included intraoperative complication rates and level of complexity of cataract surgeries performed by resident trainees and staff surgeons. RESULTS: Resident trainees were involved in 44% of surgeries. Of those, 82% were completed in their entirety by a resident and 18% were performed by both the staff surgeon and resident. Staff surgeons performed 56% of all surgeries without resident involvement. Sixty-seven percent of surgeries were simple and 33% were complex, with small pupil or intraoperative floppy-iris syndrome being the most common reason for complex cases. For simple cases, there was no difference in the overall complication rates (1.7% and 2.0%; P = .52), posterior capsule rupture rates (0.9% and 0.8%; P = .76), or vitreous loss rates (0.4% and 0.2%; P = .08) between staff and residents, respectively. CONCLUSION: There were no differences in complication rates between the two groups.

Intracorneal ring segment explantation after intracorneal ring segment implantation combined with same-day corneal collagen crosslinking in keratoconus.

PURPOSE: To report the outcome and the reversibility of refractive outcomes after intrastromal corneal ring segment (ICRS) explantation in patients with keratoconus treated with ICRS implantation and same-day collagen crosslinking (CXL). METHODS: This is a retrospective review of ICRS explantation in 3 eyes of 3 patients with keratoconus that had undergone femtosecond laser-enabled placement of paired ICRS (Intacs) with same-day CXL by a single surgeon between 2008 and 2011. The main outcome measures included baseline/preexplantation/postexplantation visual acuity, refractive error, keratometry, and higher order aberrations. RESULTS: None of the patients lost best-corrected distance visual acuity lines. ICRS can be safely and easily explanted from keratoconic eyes with previous CXL. Some of the topographic benefits gained from ICRS implantation may persist after explantation. CONCLUSIONS: Despite the reversal of refractive outcomes, the preservation of topographic changes may occur in some cases after the explantation of 1 or both the segments in patients with keratoconus treated with ICRS implantation with same-day CXL.

Efficacy of single or paired intrastromal corneal ring segment implantation combined with collagen crosslinking in keratoconus.

PURPOSE: To evaluate the efficacy of single or paired intrastromal corneal ring segments (ICRS) combined with ultraviolet-A and riboflavin collagen crosslinking (CXL) in patients with keratoconus. SETTING: Cornea Unit, Toronto Western Hospital, Toronto, Ontario, Canada. DESIGN: Retrospective comparative case series. METHODS: Consecutive patients with keratoconus had femtosecond laser-assisted ICRS implantation combined with same-day CXL between 2008 and 2011. The main outcome measures included improvement in visual acuity, subjective refractive error, keratometry values, and total higher-order aberration (HOA). RESULTS: Eighty-five eyes of 74 patients with keratoconus (paired ICRS: 47 eyes of 40 patients; single ICRS: 38 eyes of 34 patients) were included in the study. The uncorrected distance visual acuity was significantly improved after single ICRS (3.4 lines; P=.04) and paired ICRS (2.7 lines; P=.01) implantation combined with CXL, while corrected distance visual acuity (CDVA) remained stable. The single and paired ICRS groups had a significant reduction in mean cylinder at 1 year (single ICRS: -3.84 diopters [D] ± 1.72 [SD] versus -2.19 ± 1.54 D, P=.02; paired ICRS: -3.91 ± 1.45 D versus -2.96 ± 1.92 D) (P=.02). There was no significant difference in total HOAs. Single ICRS implantation and paired ICRS implantation with CXL were equivalent in all refractive parameters. No patient lost lines of CDVA. CONCLUSION: As determined by corneal topography, implantation of single or paired ICRS combined with same-day CXL was safe and effective in patients with keratoconus.

Transepithelial phototherapeutic keratectomy combined with implantation of a single inferior intrastromal corneal ring segment and collagen crosslinking in keratoconus.

PURPOSE: To evaluate the efficacy of phototherapeutic keratectomy (PTK) combined with implantation of a single inferior intrastromal corneal ring segment (ICRS) and riboflavin with ultraviolet-A collagen crosslinking (CXL) performed sequentially on the same day in the management of keratoconus. SETTING: Cornea Unit, Toronto Western Hospital, Toronto, Ontario, Canada. DESIGN: Case series. METHODS: This retrospective review comprised consecutive patients with progressive keratoconus having transepithelial PTK followed by femtosecond laser-enabled placement of a single inferior ICRS and CXL on the same day by the same surgeon between December 2010 and August 2011. The main outcome measures included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), mean refraction spherical equivalent, keratometry (K), and total higher-order aberrations. RESULTS: Sixteen eyes of 13 patients were included in the study. Six months after same-day PTK combined with implantation of a single inferior ICRS and CXL, there was a significant improvement in UDVA, CDVA, and the mean and steep K values. No patient lost CDVA lines. CONCLUSION: Phototherapeutic keratectomy combined with implantation of a single inferior ICRS and CXL on the same day was a safe, effective treatment for improving visual acuity in select patients with progressive keratoconus.

Repair of eroded glaucoma drainage devices: mid-term outcomes.

PURPOSE: Glaucoma drainage devices (GDD) are used in the surgical management of medically refractory glaucoma. One late serious complication is erosion and exposure of the tube, clip, or plate. In this study, we evaluated the effectiveness of oral buccal mucous membrane allografts with corneal lamellar grafts for the repair of GDD erosions. METHODS: Retrospective consecutive observational case series. All patients who underwent buccal membrane transplants with corneal allografts for the repair of GDD erosions between 2006 and 2010 were included in this study. Primary outcomes were categorized as: (a) success: coverage of the GDD without further repair; (b) qualified success: minor perioperative complications or additional procedures required to maintain success; or (c) failure: GDD reerosion requiring surgery. RESULTS: Nineteen eyes from 17 patients with 20 GDDs were reviewed, of which there were 19 Ahmed valves and 1 Molteno implant. There were 16 cases of tube erosion, 2 cases of plate erosion, and 2 cases of pars plana clip erosion. The mean (SD) number of ocular surgeries before the buccal membrane transplant was 4.8 (2.9). The mean (SD) time to exposure from the original GDD procedure was 4.6 (3.7) years. Analysis of tube erosions alone showed a success rate of 94% after ≥ 1 buccal membrane repairs. Buccal membrane repairs in total were considered a surgical success in 85% of cases with a mean (SD) follow-up of 1.7 (1.2) years. CONCLUSIONS: Buccal membrane transplants are particularly useful in cases of tube erosion.