Agreement on keratometry readings and computed IOL power using Haigis and SRK/T formulas between ray tracing (iTrace®) and partial coherence interferometry (IOLMaster®) among patients in an outpatient surgical center

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To determine if there is an agreement between keratometry readings and intraocular lens (IOL) power calculation using Haigis and Sanders, Retzlaff and Kraff theoretical (SRK/T) formulas obtained by iTrace® and IOLMaster®.</p> <p style="text-align: justify;"><strong>METHODS:</strong> A retrospective chart review of patients who underwent preoperative biometry using both IOLMaster® and iTrace® from January 2015 to July 2015 and satisfied the inclusion/exclusion criteria were included in the study. The average keratometry, cylinder power and predicted IOL power were computed accordingly. Agreement between devices was analyzed using Bland Altman.</p> <p style="text-align: justify;"><strong>RESULTS:</strong> A total of 70 eyes from 35 study participants were included in the analysis. The means of average keratometry values obtained from IOLMaster® and iTrace® were 43.9 ± 1.3 D and 43.6 ± 1.3 D respectively. The paired mean differences in the average keratometry and cylinder power between instruments were -0.3 ± 0.3 and 0.1 ± 0.4 respectively. There was a statistically significant difference in the proportion between the number of times there will be a need to change IOL power and the number of times IOL power will remain the same using the Haigis formula with a p value of <0.0005.</p> <p style="text-align: justify;"><strong>CONCLUSION:</strong> Average keratometry values, cylinder power and IOL calculation using the Haigis formula obtained by the two devices tested did not show agreement. There is agreement using the SRK/T formula. </p>

Microbiologic and histopathologic assessment of corneal biopsies in the evaluation of microbial keratitis.

PURPOSE: To investigate the utility of corneal biopsy in the evaluation of infectious keratitis; to compare results of culture and histopathologic examination of the same specimens; to investigate potential factors related to positive biopsy results. DESIGN: Retrospective, observational case series. METHODS: We reviewed medical records for all patients who underwent corneal biopsy because of infectious keratitis at the Jules Stein Eye Institute from June 1989 through June 2009. In general, biopsy specimens were both cultured and examined histopathologically. Lesion size, lesion progression, and interval from presentation to biopsy were analyzed as possible predictors of positive biopsies. RESULTS: Organisms were identified in 20 of 48 (42%) consecutive biopsies (positive cultures in 9 of 47 cases [19%]; positive histopathologic examination in 19 of 47 cases [40%]). Culture and histopathologic results were concordant in 30 of 46 biopsies (65%) for which both techniques were performed; 10 of the 16 discordant cases were culture-negative/histopathology-positive, while the remaining 6 had positive but discordant results for the 2 techniques (cultures all showed bacteria; histopathologic examination showed fungi or cysts consistent with Acanthamoeba sp.). Corneal biopsy revealed microorganisms in 12 of 27 patients (44%) with negative cultures of corneal scrapings obtained at presentation. None of the potential risk factors was statistically associated with positive biopsies. CONCLUSIONS: Corneal biopsy can be useful for identifying the cause of infectious keratitis in selected cases. Culture and histopathologic examination can provide complementary information, but discordant results may occur. Acanthamoebic and fungal infections are more likely to be identified by histopathologic examination.

Functional optical zone after myopic LASIK as a function of ablation diameter.

PURPOSE: To analyze spherical aberrations in patients who had myopic laser in situ keratomileusis (LASIK) with different optical zones and varying degrees of attempted corrections. SETTING: Laser Refractive Center, University of California, Los Angeles, USA. METHODS: This retrospective analysis comprised 78 eyes of 56 consecutive patients who had LASIK for myopia with the Alcon LADARVision excimer laser. The preoperative and 3-month postoperative functional optical zones (FOZs), a measure of spherical aberrations, were assessed in each eye. The change in FOZs was analyzed by size of the primary optical zone and degree of attempted correction. RESULTS: The mean preoperative FOZ was 6.1 mm +/- 0.6 (SD) and the mean 3-month FOZ, 5.2 +/- 1.0 mm. The mean decrease was 0.9 +/- 1.0 mm (P < .0001). The mean decreases were 0.005 +/- 0.7 mm, 0.7 +/- 0.9 mm, and 1.6 +/- 0.9 mm in the low, moderate, and high attempted correction groups, respectively (P < .05), and 1.3 +/- 0.9 mm, 1.2 +/- 1.0 mm, 0.5 +/- 1.3 mm, and 0.3 +/- 0.7 mm in optical zone groups of 6.0 to 6.5 mm, 6.6 to 7.0 mm, 7.1 to 7.5 mm, and 7.6 to 8.0 mm, respectively (P < .05). CONCLUSIONS: Larger optical zones had fewer postoperative spherical aberrations. Higher attempted corrections had larger increases in spherical aberrations. Larger treatment diameters minimized postoperative spherical aberrations.

Laser in situ keratomileusis for hyperopia with the LADARVision 4000 with centration on the coaxially sighted corneal light reflex.

PURPOSE: To analyze the visual acuity, contrast sensitivity, and target deviations in patients who had laser in situ keratomileusis (LASIK) for primary hyperopia with the ablation centered on the coaxially sighted corneal light reflex. SETTING: University-based refractive surgery practice. METHODS: Retrospective review comprised 37 consecutive patients (61 eyes) who had LASIK for hyperopia with the LADARVision 4000 excimer laser (Alcon Laboratories). Preoperative and 3-month postoperative visual acuity and contrast sensitivity, as well as the target deviation, were assessed for each eye. The change in best spectacle-corrected visual acuity (BSCVA), best spectacle-corrected contrast sensitivity (BSCCS), and target deviation from the intended correction were analyzed. RESULTS: Postoperatively, the uncorrected visual acuity (UCVA) was 20/20 or better in 44.4% of eyes. The mean deviation from target was +0.25 diopter (D) +/- 0.82 (SD), with 65.6% of eyes within +/-0.50 D of target. None eye lost 2 or more lines of BSCVA. A loss of 3 or more patches of BSCCS were seen in 6.6% of the eyes and a loss of 4 or more patches, in 1.6%. CONCLUSION: Hyperopic LASIK with LADARVision 4000 with the ablation zone centered on the coaxially sighted corneal light reflex did not adversely affect BSCVA and BSCCS.

Use of large optical zones with the LADARVision laser for myopia and myopic astigmatism.

PURPOSE: To analyze the visual acuity, contrast sensitivity, and target deviations of patients who underwent laser in situ keratomileusis (LASIK) for spherical and astigmatic myopia with up to 8.0-mm laser optical zones. DESIGN: A retrospective noncomparative interventional case series. PARTICIPANTS: Three hundred fifty-two eyes of 186 patients in a refractive surgery practice. METHODS: Chart review of consecutive patients who underwent LASIK for spherical and astigmatic myopia with the Autonomous LADARVision excimer laser. MAIN OUTCOME MEASURES: The preoperative and the 3-month postoperative visual acuity and contrast sensitivity, as well as the target deviation, were assessed for each eye. The change in best spectacle-corrected visual acuity (BSCVA), best spectacle-corrected contrast sensitivity (BSCCS), and target deviation were analyzed by size of optical zone. RESULTS: For spherical myopes, uncorrected visual acuity (UCVA) was 20/20 or better in 55.7% of eyes. The mean deviation from target was -0.19 +/- 0.64 diopters (D), with 75.3% within +/-0.50 D of the target. None of the eyes lost more than two lines of BSCVA. A loss of three or more patches (levels) of BSCCS was seen in 2.7% of eyes, whereas a loss of four or more patches of BSCCS was seen in 1.1%. For astigmatic myopes, UCVA was 20/20 or better in 61.9% of eyes. The mean deviation from target was -0.17 +/- 0.55 D, with 67.5% within +/-0.50 D of the target. No eye lost more than two lines of BSCVA. A loss of three or more patches of BSCCS was seen in 4.3% of eyes, whereas a loss of four or more patches of BSCCS was seen in 1.2%. CONCLUSIONS: Larger optical diameters did not adversely affect BSCVA and BSCCS. Postoperative target deviation with the nomogram used was accurate with larger optical zones.

Feasibility of contact lens fitting on keratoconus patients with INTACS inserts.

PURPOSE: To demonstrate the feasibility of contact lens fitting in keratoconus patients with INTACS inserts. METHODS: A chart review was conducted of all patients with bilateral keratoconus who were treated with INTACS inserts on one eye and who were subsequently referred for contact lens fitting in a university based contact lens practice between April 2000 and April 2002. The study was a retrospective, non-comparative case series. The uncorrected and best spectacle corrected visual acuity (BSCVA) after INTACS implantation surgery, postoperative best contact lens-corrected visual acuity (BCLVA), number of diagnostic contact lenses used, number of contact lenses ordered within a 4-month follow-up period, contact lens complications encountered, final base curves, final lens powers, and final wearing times were determined. RESULTS: Three keratoconic patients meeting the selection criteria were found through the chart review. Prior to surgery, all patients had uncorrected visual acuity (UCVA) of 2.0 logMAR (counting fingers). This improved to a mean of 0.81+/-0.25 logMAR (20/125-1) after surgery. Mean BSCVA also improved from 0.51+/-0.30 logMAR (20/60-2) to 0.30+/-0.16 logMAR (20/40). The mean postoperative best contact lens-corrected visual acuity was 0.02+/-0.10 logMAR (20/20-1). The number of diagnostic lenses ranged from 1 to 7. The numbers of contact lenses ordered during the 4-month follow up period ranged from 1 to 3. Two eyes were fitted with larger than usual lens designs made of rigid gas-permeable material and one eye was fitted with a toric soft lens. The final lens power ranged from +1.25 to -21.0D with a mean spherical equivalent of -7.46+/-11.89 D. Final wearing times ranged from 2.5 to 12.0h. CONCLUSION: Fitting contact lenses on keratoconus patients who have INTACS inserts is feasible and has a role in augmenting their vision.