Role of percent peripheral tissue ablated on refractive outcomes following hyperopic LASIK - Fig 2

<p><b>A</b>: Three-months post-surgery the mean difference to the expected spherical equivalent refractive outcome was -0.20±0.64 D (range -2.00D to +1.00D). Ideal correction designated with unbroken line. Achieved correction designated with broken line. B: Difference to expected refractive outcome vs proportion of corneal volume removed at 3 months post-LASIK. Dioptres(D). Greater proportion of tissue removed results in overcorrections.</p

Schematic representation of potential biomechanical changes to the cornea in response to hyperopic laser in situ keratomileusis.

<p>The lamellae severed in the periphery, are no longer under tension from their connection to the limbus and therefore contract increasing the corneal central thickness and steepening the cornea. The posterior corneal surface of the compromised cornea vaults anteriorly from the intra ocular pressure altering the corneal power.</p

Nomogram for the amount of tissue required to be removed 3mm from the corneal centre to achieve a particular refractive correction.

<p>Nomogram for the amount of tissue required to be removed 3mm from the corneal centre to achieve a particular refractive correction.</p

Subject demographics and outcomes.

<p>Spherical equivalent (SE). Dioptres (D). Dioptre sphere (DSph). Location 3mm from the corneal centre along the horizontal axis temporally (3T).</p

Factors significantly associated with the difference to the expected refractive outcome 3 months post-surgery.

<p>The deepest ablation occurs circumferentially 3mm from the corneal centre. 3T refers to a point 3mm from the corneal centre in a horizontal direction temporally. Proportionate tissue ablated at 3T is depth of tissue ablated as a fraction of total corneal thickness at 3T. Proportionate corneal volume removed is the total number of pulses divided by the total corneal volume. Correction (Sph) correction spherical equivalent. Residual bed at 3T is residual bed thickness at 3T.</p

Risk factors and causative organisms in microbial keratitis in daily disposable contact lens wear

<div><p>Purpose</p><p>This study investigated independent risk factors and causative organisms in microbial keratitis in daily disposable contact lens (CL)-wearers.</p><p>Methods</p><p>A multisite prospective case-control study was undertaken. Cases were daily disposable CL-wearers attending Moorfields Eye Hospital with microbial keratitis and those reported through a one-year surveillance study in Australia and in New Zealand. A population-based telephone survey identified daily disposable CL-wearing controls. Subjects completed a questionnaire describing CL-wear history, hygiene and demographics. The sample used for risk factor analysis was weighted in proportion to the CL-wearing population at each location. Corneal scrape results were accessed. Independent risk factors were determined using multiple binary logistic regression. Causative organisms in different CL-wear modalities were compared using a chi-squared test.</p><p>Results</p><p>963 daily disposable CL-wearers were identified, from which 67 cases and 374 controls were sampled. Independent risk factors were; wearing CLs every day compared with less frequent use (OR 10.4x; 95% CI 2.9–56.4), any overnight wear (OR 1.8x; 95% CI 1.6–2.1), less frequent hand washing (OR 1.8x; 95% CI 1.6–2.0), and smoking (OR 1.3x; 95% CI 1.1–1.6). Certain daily disposable CLs (OR 0.2x; 95% CI 0.1–0.2) had protective effects. Environmental organisms were less frequently recovered with daily disposable CLs (20%), compared with other modalities (36%; p<0.02).</p><p>Conclusion</p><p>Overnight wear, increased exposure in daily wear, smoking and poor hand hygiene are significant risk factors for microbial keratitis with daily disposable CLs. Risk varied with daily disposable CL type. The profile of causative organisms is consistent with less severe disease.</p></div

Microbial keratitis cases and controls using daily disposable contact lenses by location.

<p>Microbial keratitis cases and controls using daily disposable contact lenses by location.</p

Corneal scrape results for daily disposable wearers and wearers of other soft and silicone hydrogel lenses from three geographic sites.

<p>Corneal scrape results for daily disposable wearers and wearers of other soft and silicone hydrogel lenses from three geographic sites.</p

Independent risk factors for all and moderate/severe microbial keratitis identified by multiple logistic regression analysis.

<p>Independent risk factors for all and moderate/severe microbial keratitis identified by multiple logistic regression analysis.</p