David R Hardten

University of Minnesota Duluth, Duluth, Minnesota, United States

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Publications (83)193.88 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE: To report the outcomes of photorefractive keratectomy (PRK) enhancement after LASIK for patients diagnosed as having hyperopic and myopic refractive errors. METHODS: In this retrospective case series at a single private practice in the United States, all patients undergoing PRK enhancement after LASIK were identified. Patients with visually significant cataract, non-plano targets, and follow-up of fewer than 226 days were excluded. The primary outcome measure was uncorrected distance visual acuity (UDVA) with secondary measures of corrected distance visual acuity (CDVA) and postoperative refractive error. Linear regression analysis was performed for actual versus targeted change in spherical equivalent. RESULTS: Mean UDVA improved from 20/39 to 20/24 for hyperopes (n = 14; P < .002) and from 20/45 to 20/22 for myopes (n = 29; P <.0000001) after enhancement. All patients had a UDVA of 20/40 or better at their most recent follow-up visit. Fifty percent of hyperopes and 65.5% of myopes were 20/20 or better. The mean refractive error for hyperopes changed from +1.10 +/- 0.71 (range: +0.13 to +2.25 diopters [D]) to +0.38 +/- 0.66 D (range: -0.75 to +1.38 D) and from -1.21 +/- 0.61 (range: -3.25 to -0.38 D) to +0.34 +/- 0.45 D (range: -0.25 to +1.75 D) for myopes. The manifest refraction cylinder decreased from 0.84 to 0.46 D in hyperopes (P = .02) and from 0.64 to 0.26 D in myopes (P < .002). CDVA was maintained in both groups, with only one patient in each worse than 20/20. There was a nonsignificant trend toward less haze in the patients receiving mitomycin C (5.1% vs 25%, P = .14). Linear regression showed a tendency toward overtreatment in the myopic group. CONCLUSIONS: PRK is safe and highly effective for patients who previously underwent LASIK and in whom the surgeon would prefer not to perform a flap-lift enhancement.
    Journal of refractive surgery (Thorofare, N.J.: 1995) 07/2014; 30(8):549-556. DOI:10.3928/1081597X-20140711-08 · 2.78 Impact Factor
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    Bryan S Lee, David R Hardten
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    ABSTRACT: Patients with endothelial disease also often have scarring or surface corneal disease. This study examined the outcomes of phototherapeutic keratectomy (PTK) performed in patients with prior Descemet's stripping endothelial keratoplasty (DSEK).
    Clinical ophthalmology (Auckland, N.Z.) 01/2014; 8:1011-1015. DOI:10.2147/OPTH.S63982
  • International ophthalmology clinics 01/2013; 53(1):65-78. DOI:10.1097/IIO.0b013e3182713452
  • Bryan S Lee, David R Hardten
    Journal of Cataract and Refractive Surgery 12/2011; 37(12):2227. DOI:10.1016/j.jcrs.2011.10.009 · 2.55 Impact Factor
  • David R Hardten
    Journal of Cataract and Refractive Surgery 07/2011; 37(7):1370. DOI:10.1016/j.jcrs.2011.05.011 · 2.55 Impact Factor
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    David R Hardten
    Journal of refractive surgery (Thorofare, N.J.: 1995) 07/2011; 27(7):471-2. DOI:10.3928/1081597X-20110621-01 · 2.78 Impact Factor
  • Vrushali V Gosavi, David R Hardten
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    ABSTRACT: Corneal ectasia is a potentially serious complication that can occur after photorefractive keratotomy and laser-assisted in situ keratomileusis in eyes with risk factors such as inferior topographical steepening, as well as in eyes without risk factors. Better identification of forme fruste keratoconus and atypical corneas and more restraint with laser-assisted in situ keratomileusis parameters will reduce this window of corneas at risk. As we develop better technology and outcome-based evaluation criteria for preoperative screening using existing technology, we may be able to reduce the incidence of ectasia through better patient selection.
    Expert Review of Ophthalmology 08/2010; 5(4):475-481. DOI:10.1586/eop.10.40
  • David R Hardten, Vrushali V Gosavi
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    ABSTRACT: Laser correction of refractive errors is one of the most effective surgical procedures today. Even so, the selection of patients who will have the outcomes they expect remains a major challenge. Corneal ectasia, a frustrating problem that can occur naturally with diseases such as keratoconus, has also been reported after refractive surgery. This review addresses the issues surrounding the use of surface refractive surgery in patients who may have atypical topography, which is a risk factor for ectasia. At present, available tests for predicting future corneal stability can give false positives and false negatives. Although the technology for treating irregular corneal astigmatism has improved, results in eyes with irregular astigmatism are less predictable than in eyes with regular astigmatism, even when wavefront- and topography-driven treatments are used. An increased risk for corneal instability may be associated with laser vision correction (LVC), although instability is generally thought to be less of a risk with surface ablation or photorefractive keratectomy than with laser in situ keratomileusis. Surface LVC has shown good success in improving uncorrected distance visual acuity with a relatively low rate of complications, even in eyes with topographic irregularities.
    Journal of Cataract and Refractive Surgery 09/2009; 35(8):1437-44. DOI:10.1016/j.jcrs.2009.05.006 · 2.55 Impact Factor
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    ABSTRACT: To investigate the outcomes of wavefront-guided photorefractive keratectomy (WG PRK) using prophylactic mitomycin C (MMC) in eyes that had previously undergone radial keratotomy (RK). Retrospective, observational, consecutive case series. Thirty-two eyes of 27 patients with previous RK that underwent WG PRK with MMC. The records were reviewed of consecutive RK patients whose eyes underwent WG PRK with MMC in 4 centers with postoperative follow-up of 6 months or longer (range, 6-21 months). Eyes were divided into myopic WG PRK and hyperopic WG PRK groups based on their preoperative spherical equivalent (SE). Preoperative best spectacle-corrected visual acuity (BSCVA) was compared with postoperative uncorrected visual acuity (UCVA) and BSCVA to ascertain efficacy and safety. Change in SE and attempted versus achieved SE were evaluated. Incidences of haze and other complications were recorded. Uncorrected visual acuity, BSCVA, SE, corneal haze, and other complications. In the myopic WG PRK group (n = 9), UCVA improved by 3 lines on average (P = 0.015) with UCVA of > or =20/20 in 56% and > or =20/40 in 100% of eyes; 55% were within 0.5 diopter (D), and 100% were within 1 D of attempted refraction. In the hyperopic WG PRK group (n = 23), UCVA improved for 3 lines on average (P<0.001), with UCVA of > or =20/20 in 48% and > or =20/40 in 100% of eyes; 57% were within 0.5 D and 74% were within 1 D of attempted refraction. One eye lost 2 lines of BSCVA as a result of the development of mild to moderate haze, but recovered in 4 months. No eyes lost more than 2 lines of BSCVA. Six eyes (19%; 6/32) experienced the development of haze in the postoperative course, with mild to moderate haze in 1 eye and trace haze in the other 5 eyes. No other complications were noted. Wavefront-guided PRK with MMC in eyes with prior RK improved the UCVA significantly and was safe over the short follow-up of this series. Although haze occurred, no eye suffered persistent visual loss of 2 or more lines. Proprietary or commercial disclosure may be found after the references.
    Ophthalmology 07/2009; 116(9):1688-1696.e2. DOI:10.1016/j.ophtha.2009.05.013 · 6.17 Impact Factor
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    ABSTRACT: To test an anecdotally reported cataract grading system predictive of a 20/50 visual threshold in cataract-induced vision loss using cobalt blue light. Hennepin County Medical Center, Minneapolis, Minneapolis VA Medical Center, Minneapolis, and Regions Hospital, St. Paul, Minnesota, USA. Four observers evaluated pure nuclear cataracts using a standardized cobalt-blue-light protocol. Observers graded a nuclear cataract as positive if the posterior capsule was visualized with cobalt blue light and negative if the posterior capsule was not visualized. Results of the grading were compared with cataract-induced vision loss in an attempt to establish a threshold for lost visual acuity in grading cataracts with cobalt blue light. The study design was prospective observation of a cohort with a visually significant cataract. This study did not show a clear visual acuity threshold for cataract-induced vision loss using a standardized cobalt-blue-light protocol. Overall, 26.3% (95% confidence interval, 13.4-40.2) of all 20/40 or less dense nuclear cataracts had visible posterior capsules using cobalt blue light, with good estimated interobserver agreement. Although cobalt blue light is selectively absorbed by yellow pigment in an aging nuclear cataract, its ability to predict visual acuity loss due to lens opacity was limited.
    Journal of Cataract and Refractive Surgery 03/2009; 35(2):312-7. DOI:10.1016/j.jcrs.2008.10.035 · 2.55 Impact Factor
  • Ophthalmology 11/2008; 115(10):1849; autor reply 1849-50. DOI:10.1016/j.ophtha.2008.04.028 · 6.17 Impact Factor
  • Sandy Pham-Vang, David R Hardten
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    ABSTRACT: Any etiology of epithelial defect can lead to severe bacterial keratitis. Patients with recurrent corneal erosions suffer repeated corneal epithelial defects without significant trauma and therefore are at risk of infectious keratitis more frequently than someone without recurrent erosions. A stromal infiltrate with an overlying area of epithelial defect can be challenging to differentiate between infectious and noninfectious inflammatory conditions. It is important for clinicians to appreciate the clinical findings in these cases and initiate aggressive treatment promptly. A 32-year-old woman presented with a history of anterior basement membrane dystrophy and recurrent corneal erosions. She had symptoms of redness, pain, foreign body sensation, photophobia, epiphora, and burning in her left eye that started 2 days before the visit to our office. Examination showed a large epithelial defect with dense stromal infiltrate inferiorly on the cornea that appeared white and milky with diffuse cellular infiltrate as well as 3+ cells in the anterior chamber. Laboratory results were positive for bacterial keratitis (Staphylococcus aureus). Infectious presentation should be considered visually threatening and treated immediately and aggressively. Early intervention is important to help avoid severe complications.
    Optometry (St. Louis, Mo.) 10/2008; 79(9):505-11. DOI:10.1016/j.optm.2007.11.012 · 1.34 Impact Factor
  • David R Hardten, Marlane J Brown, Sandy Pham-Vang
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    ABSTRACT: To determine whether a new category of artificial tear product, carboxymethylcellulose 0.5% with compatible solutes (CMC-solutes) (Optive, Allergan, Inc., Irvine, California) improves clinical outcomes when used adjunctively with topical cyclosporine 0.05% (Restasis, Allergan, Inc., Irvine, California) for the treatment of ocular surface disease. Nineteen patients with ocular surface disease treated with cyclosporine 0.05% for at least 3 months and who had previously used other artificial tears adjunctively were enrolled. Patients discontinued their previous artificial tear and used CMC-solutes, concomitant with topical cyclosporine 0.05%. Corneal evaluation and tear production parameters were evaluated before and during combined CMC-solutes/cyclosporine treatment. Patients also completed a questionnaire before and during treatment with combined CMC-solutes/cyclosporine. Follow-up was at 1 and 3 months. Most objective measures of ocular surface health were unchanged, but an improvement in conjunctival lissamine green staining and tear break-up time was found. Conjunctival lissamine green staining scores improved from 3.4 +/- 2.5 to 1.9 +/- 2.5 by Month 3 (p = 0.004). Tear break-up time improved from 4.6 +/- 3.9 s pre-treatment to 5.3 +/- 3.8 s post-treatment (p = 0.049). Ocular Surface Disease Index (OSDI) scores improved from 16.2 +/- 9.4 at baseline to 11.5 +/- 8.9 at month 3 (p = 0.007). Subjectively, patients graded their ocular discomfort as 2.7 at baseline and as 2.3 at Month 3 (p = 0.049). At Month 3, 89.5% of patients said they liked CMC-solutes as well or better than previous drops they had used. All patients said CMC-solutes provided similar or improved relief of symptoms of dry eye than previous eye drops. There were no tear-related adverse events reported. In this study, CMC-solutes, when used in conjunction with cyclosporine 0.05%, provided patients with an improvement in objective signs and subjective symptoms of ocular surface disease compared to their previous artificial tears. Further studies are warranted.
    Current Medical Research and Opinion 10/2007; 23(9):2083-91. DOI:10.1185/030079907X219670 · 2.37 Impact Factor
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    ABSTRACT: To describe the clinical presentation and histopathologic findings in a case of explantation of an AlphaCor artificial cornea implant caused by exposure of the skirt. We describe the case report of a 46-year-old man who suffered trauma to the right eye, resulting in 4 failed penetrating keratoplasties (PKPs). Subsequently, an AlphaCor implantation was performed with some visual improvement. Slightly more than 2 years after the implant, skirt exposure occurred, possibly secondary to infectious keratitis in an area of a ruptured bulla, and explantation was performed. Corneal stability was established with repeat corneal transplantation. Histopathologic evaluation of the surgical specimen revealed chronic nongranulomatous inflammation and fibrosis in the peripheral skirt, indicating that biointegration was maintained. However, peripheral corneal stromal melting led to skirt exposure. Focal calcification, as well as retroprosthetic membrane formation, was also identified. The AlphaCor implant is a viable method of treatment for multiple failed PKPs, but it may be associated with unique complications, including corneal stromal melting, focal calcification, and retroprosthetic membrane formation. Infectious keratitis may be a risk factor for corneal stromal melting and needs to be managed aggressively. Explantation of the implant is essential if the skirt is exposed.
    Cornea 10/2007; 26(8):1004-7. DOI:10.1097/ICO.0b013e3180e799f0 · 2.36 Impact Factor
  • Thomas C Prager, David R Hardten, Benjamin J Fogal
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    ABSTRACT: Accurate biometry and intraocular lens (IOL) calculations have consequence in patient satisfaction and depend on correct determination of eye length, IOL position, refractive power of the cornea, and selection of the proper IOL formula. Familiarity with these variables will make it easier to achieve precise results in both the intact eyes and eyes that have had previous surgeries, including keratorefractive procedures. This articles provide practical tips and methods to avoid refractive surprises.
    Ophthalmology Clinics of North America 01/2007; 19(4):435-48. DOI:10.1016/j.ohc.2006.07.009
  • 01/2006: pages 177-187;
  • Dennis C. Lu, David R. Hardten, Richard L. Lindstrom
    01/2006: pages 235-256;
  • Daniel H Chang, David R Hardten
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    ABSTRACT: Many patients who have undergone corneal transplantation are unable to achieve satisfactory visual acuity with spectacle and contact lens correction alone. For these patients, refractive surgery becomes a viable option to reduce the post-keratoplasty ametropia. With the many recent advances in refractive surgery for naturally occurring refractive error, new possibilities arise for application to this complicated set of patients. This review discusses key recent developments in refractive surgery after corneal transplantation. The biomechanical effects of incisional keratotomy on post-keratoplasty corneas continue to be studied, and these techniques remain a common and simple method of reducing astigmatism. Photorefractive keratectomy, previously problematic for regression and haze formation, is gaining new prominence as early experience with the adjunctive use of mitomycin C has demonstrated good results. Long-term studies with laser in-situ keratomileusis (LASIK) have continued to show good safety and efficacy. Modern developments in cataract surgery appear to have lower incidences of graft rejection and failure. Developments in lens implantation technology continue to offer expanding options for intraocular refractive surgery. Although visual rehabilitation after corneal transplantation remains a formidable challenge, developments in refractive surgery for naturally occurring ametropias directly translate into an improved ability to help these most challenging refractive cases. Continued research will bring about improved efficacy while maintaining a high level of safety.
    Current Opinion in Ophthalmology 09/2005; 16(4):251-5. DOI:10.1097/01.icu.0000170523.80775.e7 · 2.64 Impact Factor
  • Raymond S Loh, David R Hardten
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    ABSTRACT: To report persistent unilateral flap edema following laser in situ keratomileusis (LASIK) in patients with asymmetrical central corneal thickness. Minnesota Eye Consultants, Minneapolis, Minnesota. Retrospective, noncomparative interventional case series. We examined 6 eyes of 3 patients with asymmetrical preoperative pachymetry who developed persistent unilateral flap edema after uneventful myopic LASIK in the eye with thicker preoperative pachymetry. All cases had asymmetrical preoperative pachymetry with flap edema developing in the eye with higher preoperative mean central corneal thickness (CCT) values, preoperative mean CCT subject eye 622 microm (range 556-664 microm) versus fellow eye 583 microm (range 510-621 microm). There was no associated ocular inflammation or rise in intraocular pressure. Significant flap edema resolved on a combination treatment of topical steroid and hypertonic saline. Laser in situ keratomileusis can cause temporary endothelial cell dysfunction or stress, which manifests as temporary flap edema and subclinical corneal thickening. The edema appears to be limited to the actual flap and there was no loss of epithelial integrity in these eyes and no clinically noticeable interface fluid. This new clinical entity appears to occur in patients with asymmetrical preoperative corneal pachymetry and is associated with postoperative specular microscopy abnormalities. In cases with unexplained asymmetrical corneal thickness, preoperative evaluation should include specular microscopy to evaluate for risk features that may increase the chances of a slower postoperative recovery.
    Journal of Cataract and Refractive Surgery 06/2005; 31(5):922-9. DOI:10.1016/j.jcrs.2004.08.058 · 2.55 Impact Factor
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    ABSTRACT: To investigate the prevalence of microorganisms on ultrasound biometry equipment and cleaning habits. Observational case series. Thirty-four university-based and private ophthalmology clinics. In a prospective multicenter study, clinics representative of every region of the country sampled their fixed immersion biometry equipment (i.e., ultrasound probe, immersion shell, and infusion tubing) for bacteria and fungi. Assessment of the cleaning habits for this equipment was conducted by way of a standard questionnaire that included type of fluid and delivery method, frequency of fluid change, method of cleaning the probe and shell, and frequency of tubing change and/or cleaning. Frequency (prevalence), descriptive statistics, and type of microorganisms. Eighteen samples (53% [18/34]) grew organisms from either the probe/shell or tubing. Positive cultures were found in 32% (11/34) of the immersion shell/probes and in 31% (10/32) of the infusion tubing samples. The bacteria most commonly cultured from both probe/shell and tubing was coagulase-negative Staphylococcus, whereas Penicillium species was the most commonly cultured fungus (exclusively from the probe/shell). Overall, fungi (Penicillium and Alternaria species) were cultured in 12% of the probe/shell samples. Only 14% of the study sites adequately disinfected the probe/shell according to Centers for Disease Control and Prevention (CDC) guidelines, which recommend a 5-minute soak in antiseptic. The bacteria and fungi that colonize biometry equipment are not being adequately eliminated by the cleaning/disinfecting techniques employed in most ophthalmology clinics. These results also may apply to contact biometry, pachymetry, and tonometry equipment as well. Clinicians should follow the CDC recommendations for disinfecting instruments that come in contact with the eye, and the infusion tubing should be changed after each patient.
    Ophthalmology 06/2005; 112(5):e13-8. DOI:10.1016/j.ophtha.2005.01.030 · 6.17 Impact Factor

Publication Stats

1k Citations
193.88 Total Impact Points


  • 1992–2009
    • University of Minnesota Duluth
      Duluth, Minnesota, United States
  • 2007
    • University of Wisconsin–Madison
      • Department of Ophthalmology and Visual Sciences
      Madison, Wisconsin, United States
  • 2000
    • University of California, San Diego
      • Department of Ophthalmology
      San Diego, California, United States
  • 1999
    • Unidad Oftalmologica de Caracas
      El Cafetal, Estado Miranda, Venezuela
  • 1997
    • Jules Stein Eye Institute
      Maryland, United States