Photorefractive Keratectomy in Experienced U.S. Naval Aviators: A Prospective Evaluation.

PURPOSE: To report on the prospective evaluation of photorefractive keratectomy (PRK) in experienced ametropic naval aviators that led to the approval of refractive surgery for military pilots. METHODS: This was the first study evaluating refractive surgery in naval aviators. Return to flight status after PRK and clinical outcomes and subjective and objective flight performance were evaluated. RESULTS: A total of 785 U.S. naval aviators were enrolled in the study. Average preoperative refraction was -2.92 ± 1.73 diopters (D) (range: +5.25 to -9.13 D). By 6 months, 85.9% of eyes were within ±0.50 D and 96.4% were within ±1.00 D of emmetropia. 94.4% of eyes achieved 20/20 or better, 74.3% had 20/16 or better, and 45.2% had 20/12.5 or better uncorrected distance visual acuity (UDVA) at 6 months. A total of 78.5% of aviators met return-to-flight criteria by 4 weeks, 83.3% by 8 weeks, and 90.8% by 12 weeks following PRK. All aviators eventually returned to full flight status. Cumulative flight experience included logging more than 48,000 flight hours and 19,500 landings in the 6 months following PRK. Psychometric questionnaire results showed that 78% reported improved ability to detect other aircraft and 92% reported improved ability to land on an aircraft carrier (82% significantly improved) compared to wearing corrective lenses. No one felt their vision was worse in these dynamic environments. All aviators indicated they would undergo the procedure again and would recommend it to a fellow aviator. CONCLUSIONS: This prospective study in U.S. naval aviators determined PRK to be safe and effective in a unique patient population operating in a visually demanding and hazardous environment. The program continues to be enthusiastically supported by aviators and PRK is now allowed in all branches of the military and for National Aeronautics and Space Administration astronauts. [J Refract Surg. 2024;40(6):e371-e380.].

Photorefractive Keratectomy in Student Naval Aviators: Outcomes of the U.S. Navy Accessioning Study.

PURPOSE: To present the outcomes of the U.S. Navy photorefractive keratectomy (PRK) accessioning study conducted between 2000 and 2005 that helped lead to the acceptance of laser vision correction within the U.S. aviation industry. METHODS: In this prospective masked study, a total of 301 students who had PRK and underwent naval flight training were compared to 4,368 untreated peers. Three training pipelines were compared: propeller/jet transport, jet fighters, and helicopters. The evaluated metrics were flight and academic performance (assessed for the primary and advanced stage of the training as normalized Navy Standard Score [NSS]), as well as the student attrition rate from training. RESULTS: The attrition rate was lower in the PRK group compared to controls (15.9% vs 23.2%; P = .004). In the primary stage of training, students who had PRK outperformed controls in flight training performance in the propeller/jet transport pipeline (average NSS after PRK: 52.4 ± 7.5 vs controls: 50.7 ± 6.4, P = .02), but the flight performance in the jet fighter and helicopter pipelines was comparable between the two groups. Academic performance in the primary stage of training was approximately 7% to 13% higher in students who had PRK for all training pipelines. During the advanced training stage, there was no difference in the flight performance between the groups in any of the presented pipelines. Academic performance was significantly better for students who had PRK in the helicopter pipeline (51.2 ± 11.0 vs 46.7 ± 11.7 P < .001) but comparable between the two groups in the remaining pipelines. CONCLUSIONS: Refractive surgery did not have adverse effects on flight performance metrics. Pilots who had PRK had comparable or better outcomes than their untreated peers. [J Refract Surg. 2024:40(3):e173-e181.].

The Safety and Biological Activity of OTT166, a Novel Topical Selective Integrin Inhibitor for the Treatment of Diabetic Eye Disease: A Phase 1b Study.

BACKGROUND AND OBJECTIVES: To evaluate the safety, tolerability, and biological activity of a topical selective integrin inhibitor (OTT166) eyedrop administered BID for diabetic retinopathy (DR) and diabetic macular edema (DME). STUDY DESIGN/MATERIALS AND METHODS: A prospective, multicenter, randomized, double-masked Phase 1b study. Subjects with nonproliferative DR and DME with central subfield thickness (CST) &gt; 325 microns were randomized to OTT166 eyedrops (2.5% or 5%) BID for 28 days. Subjects were followed for an additional 28 days after treatment cessation. RESULTS: Forty-four subjects were enrolled. No drug-related serious adverse events (SAEs) and two drug-related adverse events (AEs) were reported. OTT166 was well-tolerated with no evidence of ocular toxicity. Best-corrected visual acuity (BCVA) remained stable. Mean central retinal thickness (CRT) overall was variable: +12.8/+1.8 microns at Day 28 (end of treatment) and -50.3/+5.5 microns at Day 56 (end of study) for the 2.5% and 5% groups, respectively. Median CRT overall demonstrated consistent reduction by end of study: -39.0/-16.5 microns for the 2.5% and 5% groups, respectively. Median responses were greater in the treatment-naïve group (-41.5/-26.0 microns for the 2.5% and 5% groups, respectively). Thirty-seven percent of 'responder' subjects exhibited a mean reduction in CRT of 46.6 microns on optical coherence tomography (OCT) at end of treatment (Day 28) which persisted to end of the study (Day 56) - mean reduction of 67.4 microns, suggesting a durable effect. CONCLUSION: OTT166 eyedrops were safe, well-tolerated, and demonstrated biological activity in 37% of responders. These results warrant further evaluation of OTT166 eyedrops. <b>[<i>Ophthalmic Surg Lasers Imaging Retina</i> 2022;53:553-560.]</b>.

Expert Opinion on Management of Intraocular Inflammation, Retinal Vasculitis, and Vascular Occlusion after Brolucizumab Treatment.

PURPOSE: Recent reports have described a spectrum of uncommon findings of intraocular inflammation (IOI), retinal vasculitis, or retinal vascular occlusion in patients with neovascular age-related macular degeneration (nAMD) treated with intravitreal injection (IVI) of brolucizumab. We present guidance on the clinical presentation of this spectrum and propose recommendations for management of these events. DESIGN: PubMed literature review and expert opinion panel. PARTICIPANTS: A working group of international medical experts and Novartis medical personnel. METHODS: The working group deliberated on the clinical presentations and used a 3-pronged approach to develop management recommendations based on (1) critical appraisal of scientific literature; (2) clinical insights from the HAWK and HARRIER trials, postmarketing reports, and assessments from an independent Safety Review Committee (SRC); and (3) their clinical experience. MAIN OUTCOME MEASURES: Management recommendations for a spectrum of ocular inflammatory events after treatment with brolucizumab or other anti-vascular endothelial growth factors (VEGFs). RESULTS: Based on insights gained from the available information and the expertise of the contributors, recommendations were proposed for ocular examinations, imaging modalities, and treatment strategies for management of this spectrum of events. Patients should be educated to promptly report any relevant or persistent symptoms after IVI to facilitate timely intervention. Patients diagnosed with IOI should be evaluated for concomitant retinal vasculitis or retinal vascular occlusive events. Clinical examination can be augmented with multimodal imaging techniques, including widefield imaging, fluorescein angiography (with peripheral sweeps), and OCT. Once confirmed, the ongoing brolucizumab treatment should be suspended and intensive treatment with potent corticosteroids (topical, subtenon, intravitreal, or systemic) is recommended, which may be supplemented with other treatment strategies depending on the severity. Based on the clinical outcome of these events, individualized treatment with locally available standard of care should be considered for the underlying nAMD. CONCLUSIONS: These recommendations emphasize the need for early diagnosis, prompt and timely intervention, intensive treatment, and frequent monitoring to minimize the risk of progression of these events. The proposed recommendations may facilitate a consistent management approach of this spectrum of ocular inflammatory events should they arise in nAMD after treatment with brolucizumab or other anti-VEGFs.

Laser in situ keratomileusis in United States Naval aviators.

PURPOSE: To evaluate the safety and efficacy of femtosecond-assisted wavefront-guided laser in situ keratomileusis (LASIK) as well as higher-order aberrometric changes in a population of active-duty United States Naval aviators. SETTING: Navy Refractive Surgery Centers, San Diego, California, and Portsmouth, Virginia, USA. DESIGN: Prospective noncomparative 2-site study. METHODS: In this study of femtosecond-assisted wavefront-guided LASIK, 3 groups were differentiated according to the refractive status: myopia, mixed astigmatism, and hyperopia. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, mesopic low-contrast CDVA, higher-order aberrations (HOAs), and patient satisfaction were evaluated during a 3-month follow-up. RESULTS: The study enrolled, treated, and included for analysis 548 eyes with myopia, 60 eyes with mixed astigmatism, and 25 eyes with hyperopia. The UDVA was 20/20 or better in 98.3% of eyes with myopia and mixed astigmatism at all postoperative visits and in 95.7% of hyperopic eyes 3 months postoperatively. The gain in CDVA was 1 or more lines in 39.2%, 41.1%, and 30.4% of myopic, mixed astigmatic and hyperopic eyes, respectively. Loss of 2 lines of CDVA after surgery occurred in 2 myopic eyes (0.4%). At 3 months, a mean change of +0.03 µm ± 0.10 (SD) and +0.05 ± 0.08 µm was observed in higher-order root mean square and primary spherical aberration, respectively. Of the patients, 95.9% said they believed that LASIK had helped their effectiveness as Naval aviators and 99.6% would recommend the same treatment to others. CONCLUSION: Femtosecond-assisted wavefront-guided LASIK was an efficacious and safe option for refractive correction in Naval aviators, enabling a quick return to flight status. FINANCIAL DISCLOSURE: Drs. Tanzer and Schallhorn are consultants to Abbott Medical Optics, Inc. No author has a financial or proprietary interest in any material or method mentioned.

Topical cyclosporine A for postoperative photorefractive keratectomy and laser in situ keratomileusis.

PURPOSE: To compare the stability and predictability of the refractive outcomes in eyes treated with photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) with and without postoperative use of topical cyclosporine A emulsion. SETTING: Naval Medical Center San Diego Refractive Surgery Center, San Diego, California, USA. DESIGN: Randomized clinical trial. METHODS: Patients had PRK or LASIK and were randomized, pairwise, to a standard postoperative treatment regimen with or without the addition of topical cyclosporine A 0.05% emulsion twice daily for 3 months postoperatively. Visual acuity, mesopic contrast acuity, refractions, and ocular symptoms were assessed through the 3-month examination. Tear-film samples (cytokines and chemokines) were analyzed preoperatively and 1 week and 1 and 3 months postoperatively. RESULTS: The PRK group comprised 70 patients and the LASIK group, 54 patients. The addition of topical cyclosporine A twice a day after PRK or LASIK did not confer special benefits in terms of achievement of target refraction, final uncorrected distance visual acuity (UDVA), or rate of visual recovery (all P>.05, multivariate analysis of variance [MANOVA]). There was no significant difference in tear-film composition based on measurement of matrix metalloproteinase-9, interleukin (IL)-6, or IL-8 recovery (all P>.05, MANOVA). CONCLUSION: The addition of topical cyclosporine A twice daily for 3 months after PRK or LASIK did not provide a significant benefit in the rate of visual recovery, final UDVA, or patient symptoms, nor did it significantly change measured inflammatory mediators (cytokines) present in the tear film.

Femtosecond lasers for LASIK flap creation: a report by the American Academy of Ophthalmology.

OBJECTIVE: To review the published literature to assess the safety, efficacy, and predictability of femtosecond lasers for the creation of corneal flaps for LASIK; to assess the reported outcomes of LASIK when femtosecond lasers are used to create corneal flaps; and to compare the differences in outcomes between femtosecond lasers and mechanical microkeratomes. METHODS: Literature searches of the PubMed and Cochrane Library databases were last conducted on October 12, 2011, without language or date limitations. The searches retrieved a total of 636 references. Of these, panel members selected 58 articles that they considered to be of high or medium clinical relevance, and the panel methodologist rated each article according to the strength of evidence. Four studies were rated as level I evidence, 14 studies were rated as level II evidence, and the remaining studies were rated as level III evidence. RESULTS: The majority of published studies evaluated a single laser platform. Flap reproducibility varied by device and the generation of the device. Standard deviations in flap thicknesses ranged from 4 to 18.4 µm. Visual acuities and complications reported with LASIK flaps created using femtosecond lasers are within Food and Drug Administration safety and efficacy limits. Of all complications, diffuse lamellar keratitis is the most common after surgery but is generally mild and self-limited. Corneal sensation was reported to normalize by 1 year after surgery. Unique complications of femtosecond lasers included transient light-sensitivity syndrome, rainbow glare, opaque bubble layer, epithelial breakthrough of gas bubbles, and gas bubbles within the anterior chamber. CONCLUSIONS: Available evidence (levels I and II) indicates that femtosecond lasers are efficacious devices for creating LASIK flaps, with accompanying good visual results. Overall, femtosecond lasers were found to be as good as or better than mechanical microkeratomes for creating LASIK flaps. There are unique complications that can occur with femtosecond lasers, and long-term follow-up is needed to evaluate the technology fully.

Delayed diagnosis of microsporidial stromal keratitis: unusual Wessely ring presentation and partial treatment with medications against Acanthamoeba.

The authors report a case of an immunocompetent 38-year-old male who presented with an indolent keratitis that eluded diagnosis after multiple cultures taken over 9 months. He was started initially on medications against Acanthamoeba, after presenting with a nearly complete corneal ring 2 months after trauma. These medications likely partially treated his condition, thereby making laboratory diagnosis more difficult. He was identified as having Encephalitozoon hellum by PCR. The patient subsequently underwent cornea transplant after a full course of medical treatment and recovered best-corrected visual acuity of 20/20.

Why preoperative acuity predicts postoperative acuity in wavefront-guided LASIK.

PURPOSE: To critically evaluate the following clinical wisdom regarding custom (wavefront-guided) laser in situ keratomileusis (LASIK) that subjects with better-than-average best-corrected visual acuity (BCVA) before surgery have a greater risk of losing BCVA postoperatively than do subjects with worse-than-average BCVA before surgery. METHODS: High contrast BCVA was measured once before and 3 months after custom LASIK in one eye of 79 subjects. Preoperative spherical equivalent refractive error ranged between -1.00 and -10.38 D. The sample was divided into one of two subsamples: eyes that had better-than-average preoperative BCVA (<-0.11 logMAR) and eyes that had average or worse-than-average preoperative BCVA (≥-0.11 logMAR). Controls were implemented for retinal magnification and for the statistical phenomenon of regression to the mean of the preoperative acuity measurement. RESULTS: On average, for the entire sample, moving the correction from the spectacle plane to the corneal plane increased letter acuity 4.7% (1 letter, 0.02 logMAR). For each subsample, the percentage regression to the mean was 57.24%. After correcting for magnification effects and regression to the mean, eyes with better-than-average preoperative acuity had a small but significant gain in acuity (∼1 letter, p = 0.040) that was nearly identical to the gain for eyes with worse-than-average preoperative acuity (∼1.5 letters, p = 0.002). CONCLUSIONS: Custom LASIK produced a statistically significant gain in visual acuity after correction for magnification effects. Dividing the sample into two subsamples based on preoperative acuity confirmed the common clinical observation that eyes with better-than-average acuity tend to remain the same or lose acuity, whereas eyes with worse-than-average acuity tend to gain acuity. However, when only one acuity measurement is taken at a single time point and the sample is subsampled nonrandomly, this clinical observation is due to a statistical artifact (regression to the mean) and is not attributable to the surgery.

Night driving simulation in a randomized prospective comparison of Visian toric implantable collamer lens and conventional PRK for moderate to high myopic astigmatism.

PURPOSE: To compare changes in simulated night driving performance after Visian Toric Implantable Collamer Lens (TICL; STAAR Surgical) implantation and photorefractive keratectomy (PRK) for the correction of moderate to high myopic astigmatism. METHODS: This prospective, randomized study consisted of 43 eyes implanted with the TICL (20 bilateral cases) and 45 eyes receiving conventional PRK (VISX Star S3 excimer laser) with mitomycin C (22 bilateral cases) for moderate to high myopia (-6.00 to -20.00 diopters[D] sphere) measured at the spectacle plane and 1.00 to 4.00 D of astigmatism. As a substudy, 27 eyes of 14 TICL patients and 41 eyes of 21 PRK patients underwent a simulated night driving test. The detection and identification distances of road signs and hazards with the Night Driving Simulator (Vision Sciences Research Corp) were measured with and without a glare source before and 6 months after each procedure. RESULTS: No significant difference was noted in the pre- to postoperative Night Driving Simulator in detection distances with and without the glare source between the TICL and PRK groups. The differences in identification distances without glare were significantly better for business and traffic road signs and pedestrian hazards in the TICL group relative to the PRK group whereas with glare, only the pedestrian hazards were significantly better. A clinically relevant change of Night Driving Simulator performance (>0.5 seconds change in ability to identify tasks postoperatively) was significantly better in the TICL group (with and without glare) for all identification tasks. CONCLUSIONS: The TICL performed better than conventional PRK in the pre- to postoperative Night Driving Simulator testing with and without a glare source present.

Phakic intraocular lens implantation for the correction of myopia: a report by the American Academy of Ophthalmology.

OBJECTIVE: To review the published literature for evaluation of the safety and outcomes of phakic intraocular lens (pIOL) implantation for the correction of myopia and myopic astigmatism. METHODS: Literature searches of the PubMed and Cochrane Library databases were conducted on October 7, 2007, and July 14, 2008. The PubMed search was limited to the English language; the Cochrane Library was searched without language limitations. The searches retrieved 261 references. Of these, panel members chose 85 papers that they considered to be of high or medium clinical relevance to this assessment. The panel methodologist rated the articles according to the strength of evidence. RESULTS: Two pIOLs have been approved by the US Food and Drug Administration (FDA): one iris-fixated pIOL and one posterior-chamber IOL. In FDA trials of iris-fixated pIOLs, uncorrected visual acuity (UCVA) was >or=20/40 in 84% and >or=20/20 in 31% after 3 years. In FDA trials of posterior-chamber pIOLs, UCVA was >or=20/40 in 81% and >or=20/20 in 41%. Satisfaction with the quality of vision with both types of pIOLs was generally high. Toric anterior- and posterior-chamber pIOLs have shown improved clinical results in European trials compared with spherical pIOLs. Comparative studies showed pIOLs to provide better best spectacle-corrected visual acuity (BSCVA) and refractive predictability and stability compared with LASIK and photorefractive keratectomy and to have a lower risk of retinal detachment compared with refractive lens exchange. Reported complications and long-term safety concerns include endothelial cell loss, cataract formation, secondary glaucoma (pupillary block, pigment dispersion), iris atrophy (pupil ovalization), and traumatic dislocation. CONCLUSIONS: Phakic IOL implantation is effective in the correction of myopia and myopic astigmatism. In cases of high myopia of -8 diopters or more, pIOLs may provide a better visual outcome than keratorefractive surgeries and better safety than refractive lens exchange. The short-term rates of complications and loss of BSCVA are acceptable. Comprehensive preoperative evaluation and long-term postoperative follow-up examinations are needed to monitor for and prevent serious complications, and to establish long-term safety.

Visual acuity recovery after late traumatic femtosecond laser in situ keratomileusis flap loss.

We report a case of traumatic flap loss from a fingernail 2 months after femtosecond laser-assisted laser in situ keratomileusis. On presentation, the patient's uncorrected visual acuity (UCVA) was 20/400 and complete flap avulsion was noted. Irrigation and treatment with mitomycin-C were done immediately, and a bandage contact lens was inserted. The epithelium healed completely over 1 week. One month after the injury, the UCVA was 20/15(-2). This case illustrates an excellent outcome from a potentially devastating event following refractive surgery in a military member.

Comparison of night driving performance after wavefront-guided and conventional LASIK for moderate myopia.

PURPOSE: To compare preoperative and postoperative changes in simulated night driving performance after wavefront-guided (wLASIK) and conventional LASIK (cLASIK) for the treatment of moderate myopia. DESIGN: Retrospective, comparative study. PARTICIPANTS: All eyes of subjects with a preoperative manifest spherical equivalent (MSE) between -4.50 and -6.00 who underwent night driving simulator (NDS) testing from 2 clinical trials were entered into the study. This comprised 38 cLASIK patients (62 eyes; mean -5.46 diopters [D] MSE) and 21 wLASIK patients (36 eyes, mean -5.20 D MSE). METHODS: Patients' records were reviewed from 2 LASIK clinical trials that had similar enrollment criteria. One trial treated patients with conventional LASIK using a bladed microkeratome (cLASIK) and the other treated with a wavefront-guided profile using a femtosecond laser (wLASIK). In both trials, patients with moderate myopia were asked to participate in NDS testing. MAIN OUTCOME MEASURES: The detection and identification distances of road hazards were measured with and without a glare source before and 6 months after LASIK. Each eye was tested independently in best-corrected trial frames by a masked operator. RESULTS: In every category, there was a mean reduction in the preoperative to postoperative NDS performance after cLASIK (mean change, -21.3 to -27.9 ft, -6.5 to -8.5 m; 95% confidence interval [CI], -12.0 to -41.3 ft, -3.7 to -12.6 m); there was a corresponding mean improvement after wLASIK (mean change +15.0 to +29.1 ft, +4.6 to +8.9 m; 95% CI, +8.3 to +41.5 ft, +2.5 to +12.6 m). Significant differences between cLASIK and wLASIK NDS performance was observed in every category (P<0.;01, Tukey's honest significant difference for unequal numbers). A clinical relevant loss of NDS performance (>0.5 seconds) was observed in 32% to 38% of cLASIK eyes for all tasks, whereas only 0% to 3% of eyes had this loss after wLASIK. Between 2% and 7% of cLASIK eyes and 11% and 31% of eyes had a significant postoperative improvement in NDS performance in every task. CONCLUSIONS: Wavefront-guided LASIK to correct myopia combined with a femtosecond laser flap significantly improved mean night driving visual performance and was significantly better than cLASIK using a mechanical keratome.

Role of depressive symptoms in patient satisfaction with visual quality after laser in situ keratomileusis.

PURPOSE: To assess the role of depressive symptoms in patient satisfaction with visual quality after laser in situ keratomileusis (LASIK). SETTING: Navy Refractive Surgery Center, Ophthalmology Department, Naval Medical Center, San Diego, California, USA. METHODS: This was a prospective study of active-duty military patients having bilateral conventional LASIK to treat low to moderate myopia with or without astigmatism. Patients completed the Armstrong Laboratory Personality Survey Depression scale preoperatively. Patients were also given a 10-point Navy questionnaire that included an assessment of patient satisfaction with visual quality at the 1- and 6-month follow-up examinations. Patients were stratified by their visual quality rating after LASIK as highly satisfied, satisfied, and less satisfied and by their depression scale score into low, medium, and high groups. A proportional odds model was developed to compare the visual quality rating between the 3 depression groups 1 and 6 months post LASIK. RESULTS: The study comprised 370 patients. An uncorrected visual acuity of at least 20/20 was achieved in 88.6% of eyes. Patients with higher levels of depressive symptoms had 3.0 times higher odds (95% confidence interval [CI], 1.2 to 7.4) of being less satisfied than those with low levels of depressive symptoms 1 month after LASIK (P

Wavefront-guided LASIK for the correction of primary myopia and astigmatism a report by the American Academy of Ophthalmology.

OBJECTIVE: To describe wavefront-guided (WFG) LASIK for the primary treatment of low to moderate levels of myopia and astigmatism and to examine the evidence on the safety and effectiveness of the procedure in comparison with conventional LASIK. METHODS: Literature searches conducted in 2004, 2005, 2006, and 2007 retrieved 209 unique references from the PubMed and Cochrane Library databases. The panel selected 65 articles to review, and of these, chose 45 articles that they considered to be of sufficient clinical relevance to submit to the panel methodologist for review. During the review and preparation of this assessment, an additional 2 articles were included. A level I rating was assigned to properly conducted, well-designed, randomized clinical trials; a level II rating was assigned to well-designed cohort and case-controlled studies; and a level III rating was assigned to case series, case reports, and poorly designed prospective and retrospective studies. In addition, studies that were conducted by laser manufacturers before device approval (premarket approval) were reviewed as a separate category of evidence. RESULTS: The assessment describes studies reporting results of WFG LASIK clinical trials, comparative trials, or both of WFG and conventional LASIK that were rated level II and level III. There were no studies rated as level I evidence. Four premarket approval studies conducted by 4 laser manufacturers were included in the assessment. The assessment did not compare study results or laser platforms because there were many variables, including the amount of follow-up, the use of different microkeratomes, and the level of preoperative myopia and astigmatism. CONCLUSIONS: There is substantial level II and level III evidence that WFG LASIK is safe and effective for the correction of primary myopia or primary myopia and astigmatism and that there is a high level of patient satisfaction. Microkeratome and flap-related complications are not common but can occur with WFG LASIK, just as with conventional LASIK. The WFG procedure seems to have similar or better refractive accuracy and uncorrected visual acuity outcomes compared with conventional LASIK. Likewise, there is evidence of improved contrast sensitivity and fewer visual symptoms, such as glare and halos at night, compared with conventional LASIK. Even though the procedure is designed to measure and treat both lower- and higher-order aberrations (HOAs), the latter are generally increased after WFG LASIK. The reasons for the increase in HOA are likely multifactorial, but the increase typically is less than that induced by conventional LASIK. No long-term assessment of WFG LASIK was possible because of the relatively short follow-up (12 months or fewer) of most of the studies reviewed.

Laser refractive surgery in the United States Navy.

PURPOSE OF REVIEW: The aim of this article is to highlight the numerous contributions the US Navy has made to the field of laser refractive surgery. It summarizes and draws together published papers, national meeting presentations, and unpublished data of clinical and laboratory studies involving the excimer laser and the laser-assisted in-situ keratomileusis (LASIK) flap. RECENT FINDINGS: Photorefractive keratectomy (PRK) is the most widely performed refractive procedure in the US Navy, but this trend is slowly changing as femtosecond laser-assisted LASIK becomes more widely performed. Based on the results of recent studies, PRK is approved for designated Naval aviators and flight officers; post-PRK students are now allowed into flight training. Wavefront-guided PRK and LASIK are more predictable and provided better results than conventional PRK and LASIK. Femtosecond laser-assisted LASIK is now a waiverable procedure for US military personnel and US Astronauts (excluding Naval aviators, as of this writing). SUMMARY: Since its personnel must meet strict visual requirements to accomplish their mission in a variety of environments, the US Navy places particular emphasis on safety and quality of vision after laser refractive surgery. The US Navy has been evaluating the safety and efficacy of laser refractive surgery since 1993 and will continue to do so.

Randomized prospective comparison of visian toric implantable collamer lens and conventional photorefractive keratectomy for moderate to high myopic astigmatism.

PURPOSE: To compare the Visian Toric Implantable Collamer Lens (TICL), a toric phakic intraocular lens (IOL), and photorefractive keratectomy (PRK) in the correction of moderate to high myopic astigmatism. METHODS: This prospective, randomized study consisted of 43 eyes implanted with the TICL (20 bilateral cases) and 45 eyes receiving PRK with mitomycin C (22 bilateral cases) with moderate to high myopia (-6.00 to -20.00 diopters [D] sphere) measured at the spectacle plane and 1.00 to 4.00 D of astigmatism. All patient treatment and follow-up occurred at the Naval Medical Center San Diego. Study follow-up was 1 day, 1 week, 1, 3, 6, and 12 months postoperative. RESULTS: Mean best spectacle-corrected visual acuity (BSCVA), change in BSCVA, proportion of cases with improvement of 1 or more lines of BSCVA, proportion of cases with BSCVA and uncorrected visual acuity (UCVA) 20/12.5 or better, proportion of cases with BSCVA and UCVA 20/16 or better (6 months, 88% vs 54%, P=.002), and predictability +/-1.00 D (6 months, 100% vs 67%, P<.001) were all significantly better in the TICL group than the PRK group at all time periods studied postoperatively. Similarly, contrast sensitivity, tested at both the 5% photopic level and the 25% mesopic level, was significantly better at all postoperative time points in the TICL group. Mean spherical equivalent refraction was closer to emmetropia (0.28+/-0.41 vs 0.76+/-0.86, P=.005), and predictability +/-0.50 D and stability of manifest refraction (+/-0.50 D and +/-1.00 D) were significantly better in the TICL group at all postoperative visits through 6 months. Mean astigmatism correction at 6 months was not significantly different between the two groups (0.52+/-0.33 vs 0.46+/-0.35, P=.450). CONCLUSIONS: The TICL performed better than PRK in all measures of safety (BSCVA), efficacy (UCVA), predictability, and stability in this comparison, supporting the TICL as a viable alternative to existing refractive surgical treatments.

Medical considerations before refractive surgery retreatment.

We report a case of a significant hyperopic shift 2 years after myopic photorefractive keratectomy with an interim of stability. The patient was an otherwise healthy man who reported a sudden change in vision when climbing to altitude. Medical considerations for refractive shifts should be looked at before retreatment is proposed. Diabetes was diagnosed in our patient; after initiation of insulin, the patient's uncorrected visual acuity returned to 20/20 in both eyes.

Stability of the laser in situ keratomileusis corneal flap in rabbit eyes.

PURPOSE: To quantify the force required to dislodge a laser in situ keratomileusis (LASIK) corneal flap in rabbits and correlate that force with sources of injury to LASIK corneal flaps in humans. SETTING: Animal Vivarium and Department of Ophthalmology, Naval Medical Center, San Diego, California, USA. METHODS: Corneal flaps were cut in 56 eyes of 30 rabbits. A -8.00 diopter excimer ablation was also performed in 32 of the eyes. Injury testing, using a burst of CO2 from a modified paintball gun, was conducted from 1 to 9 days postoperatively. Impact force was compared to that generated by mechanical trauma (fingers and a small tree branch) striking a force gauge. RESULTS: Of 43 eyes tested for injury, flaps could not be dislocated in 11 eyes (26%). There was no significant difference between eyes treated with flap only and those that also had ablation. When flaps were dislodged, the required force generally resulted in extensive intraocular injury. There was no significant difference between the force required for flap dislocation on postoperative days 1 and 9. CONCLUSIONS: In rabbits, LASIK corneal flaps were very resistant to high-speed wind trauma as early as 24 hours postoperatively. Flap stability was robust prior to the formation of collagen scar tissue, probably due to epithelial bridging at the edge of the flap and an osmotic gradient across the flap-stromal bed interface. Although this study used a rabbit model, it seems likely that both these flap adhesion mechanisms would also provide stability to the LASIK flap in humans.

Avoidance, recognition, and management of LASIK complications.

PURPOSE: To provide important concepts of the latest developments in laser in situ keratomileusis (LASIK) complication avoidance, recognition, and management. DESIGN: A perspective. METHODS: A comprehensive literature search and review of a total of 816 publications that discussed LASIK complications from 1992 to 2005 was conducted. RESULTS: The risk of visually threatening complications is inherent in any ophthalmologic surgical procedure. Not only does LASIK require the use of several complex medical devices, but there can be significant human variation in response to this surgical intervention. As a result, many potential complications can occur after LASIK. The risk of many complications can be mitigated by appropriate patient selection and preoperative, surgical, and postoperative care. Unforeseen complications will occur, despite meticulous planning, and must be managed. Important current developments in the avoidance, recognition, and management of LASIK complications are reviewed. CONCLUSIONS: Complications as a result of LASIK can threaten vision and may cause debilitating symptoms in an otherwise healthy eye. Advancing our understanding of the prevention and management of the complications of LASIK is an endeavor that must be continued as long as refractive surgery is performed.