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Biomedical subjects

David R Hardten

Publications and source records attributed to David R Hardten.

At least 19 recordsLinked to original sources
PubMed2005

Changes in contrast sensitivity after Artisan lens implantation for high myopia.

PURPOSE: To determine the effects of Artisan lens implantation on contrast sensitivity. DESIGN: Prospective consecutive interventional case series. PARTICIPANTS AND CONTROLS: Forty-nine eyes of 30 patients with myopia and myopia with astigmatism, who underwent implantation of the Artisan iris-fixated phakic intraocular lens. Preoperative testing served as the control. INTERVENTION: Implantation of the Artisan phakic intraocular lens to correct myopia. MAIN OUTCOME MEASURES: Refractive predictability and Snellen visual acuity were evaluated preoperatively and at least 4 months postoperatively. Additionally, photopic and mesopic contrast sensitivities were measured at 1.5, 3, 6, 12, and 18 cycles per degree, with and without glare testing. RESULTS: The mean preoperative spherical equivalent (SE) was -12.16 diopters (D) (range, -6.88 to -18.00). The mean postoperative SE was -0.46+/-0.58 D (range, +0.50 to -1.75). Ninety percent of eyes were within 1.00 D of the predicted result, and 39% gained > or =1 lines of best-corrected visual acuity (BCVA). When compared with preoperative measurements, postoperative contrast sensitivity was increased under photopic conditions and slightly decreased under mesopic conditions. Adverse events were one wound leak requiring resuturing in the immediate postoperative period and one subluxed lens after significant blunt trauma. No eyes lost > or =2 lines of BCVA. CONCLUSIONS: Artisan implantation for the correction of high myopia seems to be a predictable procedure. Increases in photopic contrast sensitivity values after implantation of this phakic intraocular lens stand in distinction to the decreases in photopic contrast sensitivity previously reported after LASIK correction of this degree of myopia.

Adult↗
PubMed2005

Use of the artificial iris implant in patients with aniridia.

BACKGROUND: Aniridia (or partial aniridia) often occurs as a result of a penetrating ocular trauma. This condition may cause symptoms including glare, light sensitivity, reduced vision, and asymmetric appearance. Options for these patients include specialty contact lenses, corneal tattooing, and artificial iris implants. This article details six patients who experienced penetrating trauma with significant iris tissue loss and who chose to have an artificial iris implant. CASE REPORTS: Six patients with traumatic aniridia were enrolled in a single-site, single-surgeon study. They were followed for one year postoperatively. All six were complex cases that had multiple eye problems, such as aphakia, corneal scarring, corneal graft rejection, and retinal detachment. All participants were male. All patients experienced decrease in glare and light sensitivity following artificial iris implant surgery. Two experienced improved best-corrected vision (BCVA). All six patients felt the cosmetic appearance of their affected eye improved. CONCLUSIONS: The artificial iris device provides an effective means of treating traumatic aniridia. Optometrists often work with patients who have experienced a penetrating ocular trauma, with complete or partial aniridia as a complication. In cases in which nonsurgical means are not effective in returning the patient to comfort and productivity, an artificial iris implant should be considered.

Adult↗
PubMed2004

Long term analysis of LASIK for the correction of refractive errors after penetrating keratoplasty.

PURPOSE: To determine the long-term safety and effectiveness of laser in-situ keratomileusis (LASIK) in the treatment of refractive errors following penetrating keratoplasty (PK). METHODS: A retrospective review was performed of 57 eyes of 48 patients with anisometropia or high astigmatism who were unable to wear glasses or a contact lens after PK and who underwent LASIK for visual rehabilitation. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), and corneal transplant integrity were recorded before surgery as well as up to 60 months after LASIK. RESULTS: The mean follow-up after the LASIK was 21.4 +/- 14.2 months (range 3 to 60 months). Mean preoperative spherical equivalent (SE) was -4.19 +/- 3.38 D. The mean preoperative astigmatism was 4.67 +/- 2.18 D. Preoperative BCVA was 20/40 or better in 42 eyes (74%). At 2 years the mean SE was -0.61 +/- 1.81 D, and mean astigmatism was 1.94 +/- 1.35 D for the 28 eyes with follow-up. UCVA was 20/40 or better in 12 eyes (43%), and BCVA was 20/40 or better in 24 eyes (86%) at 2 years. A gain in BCVA of 1 line or more was seen in 8 eyes (29%). Two eyes (7%) had loss of 2 or more lines of BCVA at 2 years. There were 9 eyes (16%) that developed epithelial ingrowth. Five eyes (9%) in this series had repeat corneal transplants. CONCLUSIONS: LASIK is effective for reducing ametropia after PK. Proper patient counseling is necessary because the results of LASIK after PK are not as good as, and complications are more frequent than in eyes with naturally occurring myopia and astigmatism. Complications are especially common in patients with mismatch of the donor and host cornea or in those with poor endothelial cell function.

Adult↗
PubMed2003

To lift or recut: changing trends in LASIK enhancement.

PURPOSE: To report serious complications caused by recutting laser in situ keratomileusis (LASIK) flaps for enhancement and reconsider the current preferred method of LASIK enhancement. SETTING: Multiple surgeon practices. METHODS: This retrospective noncomparative nonconsecutive case series comprised LASIK patients in the private practices of 9 experienced refractive surgeons and those reported in a survey of refractive surgeons. Case histories, refractions, corneal topographies, slitlamp photographs, and measurements of uncorrected and best corrected (BCVA) visual acuity after recutting LASIK flaps were collected. Surveys of refractive surgeons and an analysis of changing practice trends among the authors and these surgeons were assessed. RESULTS: In 12 cases, significant loss of BCVA and subjective visual difficulties resulted from recutting LASIK flaps. Most surveyed surgeons had changed their practice from recutting to lifting flaps even 9 to 10 years postoperatively with good results. CONCLUSION: Recutting flaps for enhancement should be avoided unless other alternatives are unavailable.

Adult↗
PubMed2003

Evaluation of neuroprotective qualities of brimonidine during LASIK.

PURPOSE: The effects of LASIK-induced increased intraocular pressure on the optic nerve and nerve fiber layer are poorly understood. This study evaluates the effect of LASIK on several optic nerve parameters, both structural (scanning laser polarimetry) and functional (automated perimetry). In addition, the potential neuroprotective effect of perioperative brimonidine is studied. DESIGN: Randomized self-controlled, masked trial. PARTICIPANTS: Fifty-one patients scheduled for routine, bilateral, myopic LASIK. Patients served as their own control and received brimonidine in one eye and placebo in their fellow eye. METHODS: Patients were treated with the VISX Star S3 Excimer Laser. Patients were evaluated preoperatively and at 1 day, 1 month, and 3 months after LASIK. Topical brimonidine or control vehicle was administrated three times daily for 3 days before surgery. In addition, 1 drop of the respective study drug was instilled at the end of the procedure, and the patient continued the study drug three times daily for 3 weeks after surgery in the respective (randomized) eye. MAIN OUTCOME MEASURES: Visual acuity, nerve fiber layer analysis, automated visual field, contrast sensitivity, color vision, and pupillary function. RESULTS: Brimonidine did not change the outcome of any of the parameters analyzed in this study. There was not a statistically significant change in any of the visual field parameters (mean elevation or depression, pattern standard deviation, and corrected pattern standard deviation) measured in either the placebo or brimonidine group postoperatively. However, both the placebo and brimonidine group did show a statistically significant change in many of the direct Nerve Fiber Analyzer GDx (NFA GDx) measures. The average thickness, ellipse, and superior average were generally reduced in both groups. There was, however, no statistically significant change after LASIK in either group in indirect NFA GDx parameters such as symmetry, superior ratio, inferior ratio, or superior/nasal ratio. There was no significant change in optic nerve appearance, contrast sensitivity, or color vision between treatment groups before or after LASIK. CONCLUSIONS: LASIK with or without brimonidine did not affect the structure or function of the parameters of the optic nerve studied. Direct NFA GDx measures were globally reduced after myopic LASIK; however, the ratio measures were generally unaffected. The reduction in direct, retinal nerve fiber layer measures, in the absence of change in ratio measures and other optic nerve parameters and absence of brimonidine effect, suggest an alteration in corneal birefringence after excimer laser ablation.

Administration, Topical↗
PubMed2003

Fibrin glue for the prevention of epithelial ingrowth after laser in situ keratomileusis.

We present 3 cases of recurrent epithelial ingrowth following laser in situ keratomileusis. All patients consented to flap lifting, epithelial ingrowth removal, and placement of fibrin glue (Tisseel(R) VH, Baxter) at the flap edges. Two of 3 eyes had no evidence of recurrent epithelial ingrowth within a relatively short follow-up. One eye that also had had radial keratotomy had a small nest of stable epithelial cells that had not progressed. Fibrin glue may be a useful adjunct to prevent recurrent epithelial ingrowth. There were no complications associated with its use.

Adult↗
PubMed2003

Penetrating keratoplasty and keratolimbal allograft transplantation for corneal perforations associated with the ectodermal dysplasia syndrome.

PURPOSE: To report two patients with ectodermal dysplasia-associated keratopathy treated with keratolimbal allograft transplantation and penetrating keratoplasty. METHODS: Two patients with ectodermal dysplasia suffered multiple corneal perforations. In both patients, keratolimbal allograft transplantation was performed along with penetrating keratoplasty. Histopathology of the corneal buttons was obtained. RESULTS: Histopathologic examination showed chronic inflammation with thin, irregular epithelium, loss of stromal tissue, and thin or absent Bowman's membrane. Both patients had multiple contributing factors predisposing them to corneal perforations including an inherent ectodermal defect, trichiasis, poor tear film, and limbal stem cell deficiency. CONCLUSIONS: Patients with keratopathy and corneal perforations associated with the ectodermal dysplasia syndrome has a poor prognosis. Keratolimbal allograft transplantation may have a role in the treatment of this disease. Longer follow-up and additional case reports will determine whether this technique confers a better prognosis than keratoplasty alone.

Adult↗
PubMed2003

Cataract surgery in patients with prior refractive surgery.

As the number and types of keratorefractive procedures increase and as the baby boomer population moves into the "cataractous decades," the number of patients requiring cataract surgery following refractive surgery grows larger each year. While technological advances in surgical instrumentation and intraocular lens (IOL) design allow us to perform cleaner, faster, and more reliable cataract extractions, the ultimate postoperative refraction depends primarily on calculations performed before surgery. Third-generation IOL formulas ( Haigis, Hoffer Q, Holladay 2, or SRK/T) provide outstanding accuracy when used for eyes with physiologic, prolate corneas. In addition, most instruments used today for measuring corneal curvature and power were designed before the era of refractive surgery. These formulas and instruments make assumptions about the anatomy and refractive properties of the cornea that are no longer valid following most keratorefractive procedures. These breakdowns in IOL calculation often result in a "refractive surprise" after cataract surgery, which may require subsequent surgical correction. This article examines recent publications of modeling studies of various methods for estimating effective K values for IOL calculation, cataract surgery case series following refractive surgery, new corneal topography technologies and methods for correcting "refractive surprises" postoperatively.

Cataract Extraction↗
PubMed2003

Comparison of designs of laser systems utilized for refractive surgery.

Several different laser types are available on the market for the practitioner to use in refractive surgery. Each laser type has certain parameters that the surgeon must understand to obtain the best refractive outcomes. Studies published in peer-reviewed literature between February 2002 and March 2003 show that refractive results across all types of lasers have improved compared with those of several years ago. A difference in refractive outcomes between lasers is impossible to directly compare, as there are no randomized studies that hold surgeon or patient characteristics constant.

Equipment Design↗
PubMed2003

Loss of vision after laser in situ keratomileusis.

PURPOSE: To research the incidence of visual loss after laser in situ keratomileusis (LASIK). METHODS: We reviewed an extensive review of the literature published by The Ophthalmic Technology Assessment Committee of the American Academy of Ophthalmology regarding the safety and efficacy of LASIK. We also reviewed other recent literature. RESULTS: For low to moderate myopia and astigmatism, LASIK is efficient, safe, and predictable with few eyes losing two or more lines of best-corrected visual acuity (BCVA). For moderate to high myopia, the results are more variable and more eyes lost two or more lines BCVA. In both cases, this BCVA occurred in studies published on or before 1999. CONCLUSION: Serious adverse complications leading to significant visual loss are probably rare. Continued development of microkeratomes and laser technology are continuing to reduce the rare complications that do occur and improve functional outcomes and patient satisfaction.

Humans↗
PubMed2002

Lasik enhancements: a comparison of lifting to recutting the flap.

PURPOSE: To compare the visual outcomes and incidence of complications of lifting with recutting the lamellar flap in laser in situ keratomileusis (LASIK) enhancement surgery. DESIGN: Retrospective case-control study. PARTICIPANTS: Two hundred twelve consecutive eyes undergoing a LASIK enhancement procedure at a single surgery location during a 5-year period. METHODS: Charts of participants were obtained and outcome measures obtained. MAIN OUTCOME MEASURES: Uncorrected visual acuity, best-corrected visual acuity, refractive error, complications. RESULTS: Relifting of flaps was performed in 164 of 212 eyes (77.4%), and recutting of flaps was performed in 48 of 212 eyes (22.6%). There were no significant differences in early visual outcomes between the two groups. At 1 year patients had significantly better uncorrected vision if the flap was lifted rather than recut (20/24.7 vs. 20/31.3, P < 0.008). In addition, the flap lift group had a significantly more stable refraction at 1 year than did the recut group (change in spherical equivalent: +0.05 diopters (D) vs. -0.57 D). The incidence of complications did not significantly differ between the two groups. CONCLUSIONS: LASIK enhancement surgery can be performed safely and effectively by either lifting or recutting a flap. Lifting the flap may show better long-term stability of refractive error and uncorrected acuity.

Adult↗
PubMed2002

Long-term analysis of LASIK for the correction of refractive errors after penetrating keratoplasty.

PURPOSE: To determine the long-term safety and effectiveness of laser-assisted in situ keratomileusis (LASIK) in the treatment of refractive errors following penetrating keratoplasty. METHODS: A retrospective review was done of 57 eyes of 48 patients with anisometropia or high astigmatism who were unable to wear glasses or a contact lens after penetrating keratoplasty and who underwent LASIK for visual rehabilitation. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), and corneal transplant integrity were recorded before surgery as well as up to 60 months after LASIK. RESULTS: The mean follow-up after the LASIK was 21.4 +/- 14.2 months (range, 3-60 months). Mean preoperative spherical equivalent (SE) was -4.19 +/- 3.38 diopters (D). Mean preoperative astigmatism was 4.67 +/- 2.18 D. Preoperative BCVA was 20/40 or better in 42 eyes (74%). At 2 years the mean SE was -0.61 +/- 1.81 D and mean astigmatism was 1.94 +/- 1.35 D for the 28 eyes with follow-up. UCVA was 20/40 or better in 12 eyes (43%), and BCVA was 20/40 or better in 24 eyes (86%) at 2 years. A gain in BCVA of one line or more was seen in eight eyes (29%). Two eyes (7%) had loss of two or more lines of BCVA at 2 years. Nine eyes (16%) developed epithelial ingrowth. Five eyes (9%) in this series had repeat corneal transplants. CONCLUSIONS: LASIK is effective for reducing ametropia after penetrating keratoplasty. Proper patient counseling is necessary because the results of LASIK after penetrating keratoplasty are not as good as, and complications are more frequent than, in eyes with naturally occurring myopia and astigmatism. Complications are especially common in patients with mismatch of the donor and host cornea and in those with poor endothelial cell function.

Adult↗
PubMedDate not supplied

Nomogram considerations with the Technolas 217A for treatment of myopia.

PURPOSE: To determine whether surgeon-specific nomogram adjustments are useful when using the Technolas 217A excimer laser for treating myopia and myopic astigmatism. METHODS: We conducted a prospective evaluation of 216 consecutive eyes with 6 months follow-up after treatment of myopia or myopic astigmatism with the Technolas 217A laser. Attempted vs. achieved change in refraction was analyzed with a statistical analysis software program. Factors such as age, corneal thickness (pachymetry), preoperative spherical equivalent refraction, preoperative cylinder, and optical zone were studied to evaluate their role in predicting refractive outcome at 6 months after LASIK. RESULTS: The mean value of attempted spherical equivalent refraction was -5.32 +/- 2.72 D. The mean achieved refractive correction at 6 months was -5.55 +/- 2.78 D, with a mean spherical equivalent of 0.13 +/- 0.54 D. The percent achieved effect at 1 month was 105%, and at 6 months, 103%. Preoperative spherical equivalent refraction and optical zone size were strong predictors of 6-month LASIK outcome. There was a 9% difference in the percent achieved effect between a 4 and 7-mm optical zone. There was no correlation between age, preoperative cylinder, or surgeon and 6-month outcome. CONCLUSIONS: Surgeons using the planoscan software on the Technolas 217A may experience a small initial overcorrection. There may be a benefit to reducing the treatment given with larger optical zones and smaller corrections.

Adult↗
PubMedDate not supplied

Peripheral keratitis following laser in situ keratomileusis.

PURPOSE: To report two different cases of sterile, peripheral keratitis following laser in situ keratomileusis (LASIK). METHODS: A report of two cases (two eyes of two patients). RESULTS: In two patients, peripheral infiltrates appeared 1 day after LASIK. One patient had a history of rheumatoid arthritis and both had peripheral corneal changes that may have represented prior inflammatory events. The presentations were quite different, with one occurring in association with an epithelial defect at the edge of the flap and the other occurring without an epithelial defect peripheral to the microkeratome cut. In the second case a similar infiltrate showed up in the unoperated fellow eye. Both patients were treated with aggressive antibiotic and corticosteroid therapy. Both patients recovered well with no loss of best spectacle-corrected visual acuity. CONCLUSION: Peripheral keratitis can occur in patients following LASIK; preoperative evidence of previous inflammation may be a marker for patients at higher risk. Rheumatoid arthritis patients may be at increased risk for this complication. With careful and aggressive management excellent visual outcomes are still possible.

Adult↗
PubMedDate not supplied

Triptans and the incidence of epithelial defects during laser in situ keratomileusis.

PURPOSE: To investigate whether the incidence of epithelial defects during laser in situ keratomileusis (LASIK) was different in patients who were taking sumatriptan (Imitrex, Glaxo Smith Kline, Pittsburgh, Pa) for migraine headaches than in those who were not. METHODS: A retrospective chart review was performed on 54 eyes of 28 patients who had been identified as taking sumatriptan and had undergone LASIK at Minnesota Eye Consultants between 1999 and 2001. These patients were compared with 54 gender- and age-matched control eyes operated on with the same microkeratome at the same location during the same period of time. The incidence of epithelial defects during LASIK was compared between the two groups. RESULTS: In the sumatriptan group, 11.1% (6 of 54) of eyes developed epithelial defects as compared to 9.3% (5 of 54) of eyes in the non-triptan group (P=.75, chi square). More recent sumatriptan exposure did not increase the incidence of epithelial defect (P=.47). In patients in whom sumatriptan was stopped >1 month prior to LASIK, 6.3% (1 of 16 eyes) had epithelial defects; in patients in whom sumatriptan was stopped <1 month prior to LASIK, 14.3% (4 of 28 eyes) developed epithelial defects; and 9.3% (5 of 54 eyes) of patients in whom no triptans had ever been used had epithelial defects (P=.70). CONCLUSIONS: There is no correlation between the use of sumatriptan for relief of migraine headaches and the generation of epithelial defects during LASIK. There appears to be no reason to stop triptans before proceeding with LASIK.

Adult↗