Comparison of stromal hydration techniques for clear corneal cataract incisions: conventional hydration versus anterior stromal pocket hydration.

Anterior stromal pocket hydration was compared with conventional hydration for preventing wound leak after 2.8 mm uniplanar clear corneal incisions (CCIs) in patients having routine cataract surgery. Conventional hydration involves hydration of the lateral walls of the main incision with visible whitening of the stroma. The anterior stromal pocket hydration technique involves creation of an additional supraincisional stromal pocket overlying the main incision, which is then hydrated instead of the main incision. Sixty-six eyes of 48 patients were included in the data analysis with 33 assigned to each study group. The anterior stromal pocket hydration technique was significantly better than conventional hydration in preventing wound leak due to direct pressure on the posterior lip of the incision.

The effect of preoperative keratometry on visual outcomes after moderate myopic LASIK.

PURPOSE: To evaluate visual outcomes in moderately myopic eyes with flat and steep corneas (preoperatively) that have been treated with laser-assisted in situ keratomileusis (LASIK). PATIENTS AND METHODS: Records of ninety-six eyes with average preoperative keratometry (K) values between 39.9 and 42.0 diopters (D) (flat) were matched with 103 eyes with preoperative K values between 46.0 and 47.2 D (steep) that underwent LASIK between March 2007 and March 2010 for moderate myopia, and were retrospectively reviewed. The primary outcome measures used to determine the effect of preoperative keratometry on visual prognosis were refraction, visual acuity, change in keratometry (ΔK), and change in spherical equivalent (ΔSE), measured at 1, 3, 6, and 12 months postoperatively. RESULTS: Significant differences were found at 6 months postoperatively between the flat group and steep group in SE (P = 0.029), sphere (P = 0.018), ΔK (P = 0.002), percentage of eyes achieving SE of -0.25 to + 0.25 D (P = 0.0125), -0.26 to -0.50 D (P = 0.003), -0.51 to -1.00 D (P = 0.044), and the percentage of eyes achieving uncorrected distance visual acuity of 20/15 or better (P = 0.0006). CONCLUSION: Moderately myopic eyes with flatter corneas preoperatively have better visual prognosis following LASIK compared with moderately myopic eyes with steeper corneas.

Tomographic corneal profile analysis of central toxic keratopathy after LASIK.

PURPOSE: To describe a case of bilateral central toxic keratopathy (CTK) in a post-laser in situ keratomileusis-treated patient using tomographic methods for more than a 1-year follow-up. METHODS: Case report and literature review. RESULTS: Tomographic analysis of a patient with bilateral CTK revealed flattening of the anterior cornea curvature and thinning at the level of anterior stromal bed, with minimal changes of the posterior curvature. A thin central flap was also noted on optical coherence tomography (OCT). Over the course of a year, the patient's hyperopic shift resolved with steepening of the anterior curvature and concomitant thickening of the flap and stromal bed. CONCLUSIONS: Using Scheimpflug imaging and Visante OCT, we demonstrated that the hyperopia that accompanies CTK is related to anterior corneal curvature changes. We also found that the majority of corneal tissue loss occurs at the anterior stromal bed mainly in the first postoperative week and is followed by a regeneration of tissue. A thin central flap was noted, and it is not clear whether this was created intraoperatively or resulted from the presence of CTK, requiring further study.

A comparison of the American Society of Cataract and Refractive Surgery post-myopic LASI K/PRK intraocular lens (IOL) calculator and the Ocular MD IOL calculator.

BACKGROUND: To compare the average values of the American Society of Cataract and Refractive Surgery (ASCRS) and Ocular MD intraocular lens (IOL) calculators to assess their accuracy in predicting IOL power in patients with prior laser-in-situ keratomileusis (LASIK) or photorefractive keratectomy. METHODS: In this retrospective study, data from 21 eyes with previous LASIK or photorefractive keratectomy for myopia and subsequent cataract surgery was used in an IOL calculator comparison. The predicted IOL powers of the Ocular MD SRK/T, Ocular MD Haigis, and ASCRS averages were compared. The Ocular MD average (composed of an average of Ocular MD SRK/T and Ocular MD Haigis) and the all calculator average (composed of an average of Ocular MD SRK/T, Ocular MD Haigis, and ASCRS) were also compared. Primary outcome measures were mean arithmetic and absolute IOL prediction error, variance in mean arithmetic IOL prediction error, and the percentage of eyes within ±0.50 and ±1.00 D. RESULTS: The Ocular MD SRK/T and Ocular MD Haigis averages produced mean arithmetic IOL prediction errors of 0.57 and -0.61 diopters (D), respectively, which were significantly larger than errors from the ASCRS, Ocular MD, and all calculator averages (0.11, -0.02, and 0.02 D, respectively, all P < 0.05). There was no statistically significant difference between the methods in absolute IOL prediction error, variance, or the percentage of eyes with outcomes within ±0.50 and ±1.00 D. CONCLUSION: The ASCRS average was more accurate in predicting IOL power than the Ocular MD SRK/T and Ocular MD Haigis averages alone. Our methods using combinations of these averages which, when compared with the individual averages, showed a trend of decreased mean arithmetic IOL prediction error, mean absolute upper limit of IOL prediction error, and variance, while increasing the percentage of outcomes within ±0.50 D.

In vivo and in vitro analysis of topographic changes secondary to DSAEK venting incisions.

INTRODUCTION: Descemet's stripping automated endothelial keratoplasty (DSAEK) venting incisions may induce irregular corneal astigmatism. The study examines in vivo and in vitro astigmatic effects of venting incisions. PATIENTS AND METHODS: In vivo analysis examined eleven eyes of eleven patients who had received DSAEK with venting incisions. A chart review of the eleven eyes including assessment of pre and postoperative refraction and topography was performed. In vitro analysis examined three cadaver eyes which received topographic imaging followed by venting incisions at 4 mm, 6 mm, and 7 mm optical zones. Topographic imaging was then performed again after the incisions. RESULTS: Postoperative topographies of eleven eyes demonstrated localized flattening at incision sites and cloverleaf pattern astigmatism. There was a significant difference in corneal irregularity measurement (P = 0.03), but no significant difference in shape factor or change of topographic cylinder. The cloverleaf pattern was found in cadaver eyes with incisions placed at 4 mm and 6 mm optical zones but not at the 7 mm zone. CONCLUSION: DSAEK venting incisions can cause irregular corneal astigmatism that may affect visual outcomes. The authors recommend placement of venting incisions near the 7 mm optical zone.

Comparison of Hanna and Hessburg-Barron trephine and punch systems using histological, anterior segment optical coherence tomography, and elliptical curve fitting models.

BACKGROUND: This study analyzes the characteristics of donor and recipient tissue preparation between the Hessburg-Barron and Hanna punch and trephine systems by using elliptical curve fitting models, light microscopy, and anterior segment optical coherence tomography (AS-OCT). METHODS: Eight millimeter Hessburg-Barron and Hanna vacuum trephines and punches were used on six cadaver globes and six corneal-scleral rims, respectively. Eccentricity data were generated using measurements from photographs of the corneal buttons and were used to generate an elliptical curve fit to calculate properties of the corneal button. The trephination angle and punch angle were measured by digital protractor software from light microscopy and AS-OCT images to evaluate the consistency with which each device cuts the cornea. RESULTS: The Hanna trephine showed a trend towards producing a more circular recipient button than the Barron trephine (ratio of major axis to minor axis), ie, 1.059 ± 0.041 versus 1.110 ± 0.027 (P = 0.147) and the Hanna punch showed a trend towards producing a more circular donor cut than the Barron punch, ie, 1.021 ± 0.022 versus 1.046 ± 0.039 (P = 0.445). The Hanna trephine was demonstrated to have a more consistent trephination angle than the Barron trephine when assessing light microscopy images, ie, ±14.39° (95% confidence interval [CI] 111.9-157.7) versus ±19.38° (95% CI 101.9-150.2, P = 0.492) and OCT images, ie, ±8.08° (95% CI 106.2-123.3) versus ±11.16° (95% CI 109.3-132.6, P = 0.306). The angle created by the Hanna punch had less variability than the Barron punch from both the light microscopy, ie, ±4.81° (95% CI 101.6-113.9) versus ±11.28° (95% CI 84.5-120.6, P = 0.295) and AS-OCT imaging, ie, ±9.96° (95% CI 95.7-116.4) versus ±14.02° (95% CI 91.8-123.7, P = 0.825). Statistical significance was not achieved. CONCLUSION: The Hanna trephine and punch may be more accurate and consistent in cutting corneal buttons than the Hessburg-Barron trephine and punch when evaluated using elliptical curve fitting models, light microscopy, and AS-OCT.

Femtosecond-assisted preparation of donor tissue for Boston type 1 keratoprosthesis.

We describe a technique for femtosecond laser-assisted preparation of donor tissue for Boston type 1 keratoprosthesis to provide accurate double punching of the donor tissue for optimized alignment in the visual axis. The technique was reproducibly performed in four donor corneas mounted in an artificial anterior chamber. This technique can provide optically centered donor tissue with smooth trephinated edges.

Retained nuclear fragment found during Descemet-stripping automated endothelial keratoplasty.

An 82-year-old man with a 2- to 3-month history of progressive visual loss due to corneal edema was referred to our center. The ocular history was significant for uneventful cataract surgery approximately 3 years earlier. Pseudophakic bullous keratopathy was diagnosed and Descemet-stripping automated endothelial keratoplasty (DSAEK) performed. During surgery, a retained nuclear fragment was discovered in the anterior chamber. The fragment was removed and the DSAEK completed successfully. At the 4-month follow-up, the symptoms had completely resolved and the uncorrected distance visual acuity in the affected eye was 20/40.

Simultaneous and sequential implantation of intacs and verisyse phakic intraocular lens for refractive improvement in keratectasia.

PURPOSE: To evaluate the safety, efficacy, and visual outcomes of simultaneous and sequential implantation of Intacs (Addition Technology, Inc, Sunnyvale, CA) and Verisyse phakic intraocular lens (AMO, Santa Ana, CA) in selected cases of ectatic corneal disease. SETTING: John A. Moran Eye Center, University of Utah, UT. METHODS: Prospective data were collected from 19 eyes of 12 patients (5 eyes, post-laser in situ keratomileusis ectasia and 14 eyes, keratoconus). Intacs segments were implanted followed by insertion of a phakic Verisyse lens at the same session (12 eyes) in the simultaneous group or several months later (7 eyes) in the sequential group. The uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), and manifest refraction were recorded at each visit. RESULTS: No intraoperative or postoperative complications were observed. At the last follow-up (19 ± 6 months), in the simultaneous group, mean spherical error was -0.79 ± 1.0 diopter (D) (range, -2.0 to +1.50 D) and cylindrical error +2.06 ± 1.21 D (range, +0.5 to +3.75 D). In the sequential group, at the last follow-up, at 36 ± 21 months, the mean spherical error was -1.64 ± 1.31 D (range, -3.25 to +1.0 D) and cylindrical error +2.07 ± 1.03 D (range, +0.75 to +3.25 D). There were no significant differences in mean uncorrected visual acuity or BSCVA between the 2 groups preoperatively or postoperatively. No eye lost lines of preoperative BSCVA. CONCLUSIONS: Combined insertion of Intacs and Verisyse was safe and effective in all cases. The outcomes of the simultaneous implantation of the Intacs and Verisyse lens in 1 surgery were similar to the results achieved with sequential implantation using 2 surgeries.

Intrastromal corneal ring segments for post-LASIK ectasia complicated by persistent pain.

A 33-year-old man who was 2 years post laser in situ keratomileusis was found to have corneal ectasia. He was intolerant of rigid gas-permeable contact lenses and eventually chose to have placement of intrastromal corneal ring segments (ICRS) (Intacs) in the right eye. Two ICRS were implanted without complication, and postoperative examination showed improved visual acuity and decreased corneal elevation on scanning-slit tomography imaging. However, over the following 2 months, he complained of persistent pain in the right eye. Confocal microscopy showed a corneal nerve touching the superonasal ICRS. The ICRS was removed, and shortly thereafter the patient's pain resolved.

Hemostatic dressings for the first responder: a review.

The military is interested in finding a hemostatic dressing that is effective in controlling hemorrhage from combat wounds, relatively inexpensive, and easy to transport. The fibrin dressing has existed for decades, but the military has been reluctant to use the dressing because it is not Food and Drug Administration approved, fairly expensive, and difficult to apply on certain wounds. Newer dressings such as the microporous polysaccharide hemosphere (TraumaDEX), mineral zeolite (QuikClot), poly-N-acetylglucosamine (HemCon), and microporous hydrogel-forming polyacrylamide (BioHemostat) dressings have addressed these deficiencies in that they are relatively inexpensive, easy to transport, and easy to apply. However, the effectiveness of these new dressings on wounds sustained in combat is still questionable according to studies and anecdotal reports from Operation Iraqi Freedom. More research is needed to draw definite conclusions about the effectiveness of these dressings in a combat setting.