Intraocular Pressure Reduction After Real-world Cataract Surgery.

PRéCIS:: A large cohort undergoing cataract extraction was retrospectively analyzed to ascertain the degree of real-world intraocular pressure (IOP) reduction in normal eyes and those with glaucoma, and a predictive formula was developed. PURPOSE: The purpose of this study was to define the real-world degree of IOP reduction after cataract extraction to guide its role as an isolated intervention for glaucoma. MATERIALS AND METHODS: A retrospective analysis was carried out of clinical data collected in 8 clinical sites in the United Kingdom from an electronic medical record system between January 2006 and May 2015. A total of 20,508 eyes without known pathology and 2251 eyes from patients with glaucoma undergoing phacoemulsification and intraocular lens insertion were included. Eyes with intraoperative complications, undergoing additional procedures, axial lengths outside 22 to 26.5 mm, preoperative IOP under 6 mm Hg or over 30 mm Hg, and copathology, except for amblyopia or glaucoma, were excluded. The main outcome measure was the change in preoperative IOP compared with the next recorded visit for up to 12 weeks. RESULTS: In eyes without pathology, the mean reduction in IOP was 1.40 mm Hg (±3.74) compared with 1.03 (±5.02), P-value <0.001, in eyes with a diagnosis of glaucoma. A multiple linear regression model identified preoperative IOP, a glaucoma diagnosis, preoperative corrected visual acuity, age, and axial length as determinants of IOP reduction. The model was validated against an independent cohort. CONCLUSIONS: We quantify mean IOP reduction achieved in a real-world setting from cataract surgery alone. In glaucomatous eyes where angle closure is not differentiated, phacoemulsification alone yields only a modest reduction of IOP.

Reduced Macular Vessel Density and Capillary Perfusion in Glaucoma Detected Using OCT Angiography.

AIMS: To evaluate retinal vasculature changes in primary open-angle glaucoma (POAG) and whether the functional visual loss correlates with parameters obtained using optical coherence tomography angiography (OCTA). MATERIALS AND METHODS: OCT and OCTA images were collected from 116 POAG eyes and 40 normal eyes in a prospective, cross-sectional observational study. Glaucomatous eyes were further divided into three groups according to a Glaucoma Staging System. Measurements of macular vessel density, ganglion cell complex (GCC), and disk retinal nerve fiber layer (RNFL) thickness were compared among groups. RESULTS: The macular vessel density, GCC, and RNFL are significantly reduced in POAG compared to normal eyes that also corresponds to the severity of glaucoma (Kruskal-Wallis test with Dunnett's correction; p < 0.0001). Visual field mean deviation correlates significantly with macular vessel density (p = 0.0028, r = 0.3), GCC (p < 0.0001, r = 0.6), and RNFL (p = 0.008, r = 0.36) in POAG. There are significant correlations between GCC and RNFL (p < 0.0001, r = 0.76) as well as macular vessel density (p < 0.0001, r = 0.48). Increased age also correlates with reduced macular vessel density in both normal (p = 0.0002, r = 0.49) and glaucomatous eyes (p < 0.0001, r = 0.48), but a greater proportionate reduction of vessel density is seen in glaucomatous eyes. CONCLUSION: Reduced macular vessel density occurs in POAG despite of age-related changes, which also correlates with reductions in RNFL and GCC measurements. OCTA can detect microstructural defects and offers potential to facilitate diagnosis of glaucoma.

Quantification of the surgically induced refractive effect of intrastromal corneal ring segments in keratoconus with standardized incision site and segment size.

PURPOSE: To determine the surgically induced refractive and keratometric effects of intrastromal corneal ring segments (ICRS). SETTING: St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom. DESIGN: Case series. METHODS: Keratoconic patients had implantation of 2 vertically aligned 0.3 mm Intacs ICRS with the incision site at 90 degrees. Principal outcome measures were changes in visual acuity and refractive and keratometric effects (analyzed using methods of Kaye and Harris) 4 months postoperatively. Subgroup analysis was based on the Krumeich classification. RESULTS: Twenty-nine eyes (29 patients) were included. There was a significant difference between the mean preoperative (-5.16 +1.93 × 162.05) and postoperative (-2.64 +1.07 × 137.25) refractive errors (P=.01), with a mean refractive surgical effect of +1.35 +1.48 × 88.71 (SD +2.76 +4.78 × 149.62), and between the mean preoperative (51.32/2.28 @ 122.33) and postoperative (48.23/2.36 @ 92.10) keratometric powers (P=.001), with a mean keratometric surgical effect of -3.87/2.54 @ 61.77 (SD 1.37/4.20 @ 136). The irregularity index in the 3.0 mm zone decreased from 11.56 diopters (D) to 8.78 D. Refractive and keratometric surgical effects showed little difference within stages I through III and were greater in stage IV. CONCLUSIONS: Placement of two 0.3 mm ICRS caused overall flattening of the cornea (2.00 D to 3.00 D), with more flattening orthogonal to the incision site at 90 degrees. Variability of this effect, principally in the steep and flat meridians, limited the predictability of ICRS. Corneal behavior may differ with other incision sites. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Adjustment of the surgical nomogram for surgery on slipped extraocular muscles.

PURPOSE: A slipped muscle is an underdiagnosed complication of strabismus surgery. Surgery necessitates intraoperative diagnosis, measurement, and resection of the empty sheath. We analyzed the results of empty sheath surgery for slipped medial and lateral rectus muscles in a large cohort of patients. METHODS: Eighty-five patients who underwent empty sheath surgery at a secondary referral center by a single strabismologist were included in the study. We retrospectively analyzed the preoperative and postoperative change in angle of deviation 6 weeks after surgery. All cases were reoperations in which an unexpected or unsatisfactory outcome followed primary surgery. Consecutive exotropias with slipped medial rectus muscles were noted in 68 patients. There were 17 esotropia cases with lateral rectus muscles slip, of which 2 were consecutive exotropias that became consecutive esotropias. Bilateral medial rectus muscle slips were found in 6 patients with consecutive exotropias. Adjustable suture surgery was performed in 27 patients. RESULTS: Resection of the empty sheath of the slipped medial or lateral rectus muscle with advancement to the original site of insertion was done in all cases; in addition, the antagonist muscle was recessed only if it was tight. The total muscle advancement was calculated in millimeters from the total amount of sheath resected, muscle advanced, and the antagonist recessed. The greater the preoperative deviation, the more surgical muscle advancement was required and the greater the change in postoperative angle of deviation. Mean change in angle of deviation was 3.13(delta) for each millimeter of muscle advancement (median = 3.00, SD = 1.72). CONCLUSIONS: The diagnosis of slipped muscle should be confirmed during strabismus surgery. The empty sheath was measured, resected, and the muscle advanced to the original site of insertion. An approximate 3(delta) change in angle of deviation was observed for every millimeter of muscle of advancement. For very large and very small deviations, surgeons should modify this to an accustomed measurement dictated by their experience.