Using the Freiburg Acuity and Contrast Test to Measure Visual Performance in USAF Personnel After PRK

Dennis, Richard; Beer, Jeremy; Baldwin, Jason; Ivan, Douglas J.; LoRusso, Frank J; Thompson, W. T.

doi:10.1097/00006324-200407000-00013

Cited by 36 publications

(19 citation statements)

References 27 publications

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“…This trend was observed in other results from the comprehensive PRK Study as well (26,67,68). However, an opposite trend was found in controls.…”

Section: Analysis Of Nvg Visual Acuity Datasupporting

confidence: 80%

“…Accordingly, the job of the Aerospace Ophthalmology Branch at the USAF School of Aerospace Medicine is to be a sentinel for aviators and ensure that nothing is done that might degrade vision or ultimately affect flying performance. This study, which was part of the larger USAF comprehensive PRK study (26,68), was specifically designed to expose any negative effects on night mesopic and NVG visual performance.…”

Section: Discussionmentioning

confidence: 99%

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Prospective Evaluation of Mesopic Night Vision and Night Vision Goggle Visual Acuity After Photorefractive Keratectomy (PRK)

Miller¹,

Thompson²,

Baldwin³

et al. 2005

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. SUPPLEMENTARY NOTES ABSTRACTThe US Air Force PRK Study involved 98 non-flying, active duty volunteer personnel. All study subjects underwent a comprehensive array of vision tests. Baseline and post-operative data were collected at the Ophthalmology Branch of the Clinical Sciences Division of the USAF School of Aerospace Medicine, in partnership with the Air Force Research Laboratory and Wilford Hall Medical Center. This report covers results from pre-and post-operative night vision goggle (NVG) visual acuity testing. 65 treated subjects and 15 untreated controls completed all post-op visits through 12 months, and 52 treated subjects and 14 untreated controls through 24 months. NVG acuities were collected on a high contrast letter chart (Bailey-Lovie), and custom made grating charts. There was a statistically significant loss of letter acuity at the 4-and 6-month post-op visits for treated subjects but not controls. Acuity returned to baseline levels by 12 months. Mean loss of acuity for groups was typically only a few letters; however, treated subjects were more likely to lose than gain acuity beyond that predicted from repeatability studies with controls.

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“…This trend was observed in other results from the comprehensive PRK Study as well (26,67,68). However, an opposite trend was found in controls.…”

Section: Analysis Of Nvg Visual Acuity Datasupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Prospective Evaluation of Mesopic Night Vision and Night Vision Goggle Visual Acuity After Photorefractive Keratectomy (PRK)

Miller¹,

Thompson²,

Baldwin³

et al. 2005

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“…This value represents the reciprocal of the CS. The logarithm of CS values was used for later statistical analysis (Bu¨hren et al 2006;Dennis et al 2004;Patel et al 2009). …”

Section: Contrast Sensitivitymentioning

confidence: 99%

Visual acuity and contrast sensitivity after posterior lamellar keratoplasty

Nielsen

Hjortdal

2011

Acta Ophthalmologica

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. Purpose: It has previously been reported that patients who suffer from Fuchs’ endothelial dystrophy (Fuchs’ ED) have decreased contrast sensibility threshold. The removal of endothelial guttata by Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) surgery has also been demonstrated to decrease intraocular light scatter and improve contrast thresholds. The purpose of this study was to compare different visual qualities in patients that had undergone DSAEK surgery in one eye while having untreated Fuchs’ dystrophy in the other eye. Methods: Thirty‐two eyes of 16 patients with bilateral Fuchs’ ED who had DSAEK surgery performed in one eye were enrolled. Visual acuity at 100% contrast and contrast sensitivity (CS) as evaluated by a modified simulation of the Freiburg Acuity and Contrast Test, was measured in both eyes of each patient. Results: Snellen visual acuity improved in treated eyes from 0.66 ± 0.35 (SD) before surgery to 0.38 ± 0.18 after surgery (log MAR units; p < 0.01). In eyes with untreated Fuchs’ dystrophy, visual acuity was 0.46 ± 0.14. In a pairwise comparison, there was no difference in Snellen visual acuity between treated and nontreated eyes (p = 0.12). Contrast sensitivity was significantly better in DSAEK‐treated eyes compared with untreated eyes. Mean log CS in DSAEK‐treated eyes was 1.06 ± 0.25 compared with a mean log CS of 0.84 ± 0.16 in untreated eyes (p < 0.01). Fourteen of 16 patients (88%) reported that vision in their DSAEK‐treated eye had the best visual quality. Conclusion: In this study, using a paired design, we demonstrate improved CS in DSAEK‐operated eyes when compared with the other eye that had untreated Fuchs’ ED despite the fact that no difference in visual quality was detected with standard Snellen visual acuity. Contrast sensitivity appears to be superior to normal visual acuity measurements in the evaluation of overall visual quality after DSAEK.

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“…Unlike several recent studies that measured visual performance of refractive surgery subjects with their most recent spectacle refraction [Schlote et al, 1999;MontesMico et al, 2003;Bailey et al, 2004;Dennis et al, 2004;Quesnel et al, 2004], we elected not to refract any of the subjects so that they may not have had their optimal acuity even though they had an acuity of at least 0.0 logMAR (i.e., 6/ 6 or 20/20). It was anticipated that the vast majority of subjects would have a visual acuity of 0.0 logMAR, or better, as they had been recently screened prior to enrolling in the College.…”

Section: Discussionmentioning

confidence: 99%

“…The contrast sensitivity loss extended to the medium and low spatial frequencies for the PRK subjects [Montes-Mico and Charman, 2002]. Dennis et al [2004] reported reductions in photopic contrast sensitivity with, and without, glare 2 years after surgery.Policing is one occupation that is visually demanding and the duties are carried out in adverse viewing conditions. Adequate vision at night is often cited by subject matter experts as being an essential requirement for policing [Shaw and Gledhill, 1995].…”

mentioning

confidence: 99%

Visual function of police officers who have undergone refractive surgery

Hovis¹,

Ramaswamy²

2006

Am. J. Ind. Med.

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Although refractive surgery police recruits and officers had reduced performance on some vision tests, these reductions were small and it is unlikely that their performance on vision related tasks would be compromised, on average. The major concern is the small number of refractive surgery candidates whose results were well outside the range of the non-surgical candidates. Their vision may be unacceptable for policing.

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Using the Freiburg Acuity and Contrast Test to Measure Visual Performance in USAF Personnel After PRK

Abstract: PRK does not appear to have affected VA, but the changes in CS might represent a true decline in visual performance. The greater disruptive effects from laser versus broadband glare may be a result of increased masking from coherent spatial noise (speckle) surrounding the laser stimulus.

Cited by 36 publications

References 27 publications

Prospective Evaluation of Mesopic Night Vision and Night Vision Goggle Visual Acuity After Photorefractive Keratectomy (PRK)

Prospective Evaluation of Mesopic Night Vision and Night Vision Goggle Visual Acuity After Photorefractive Keratectomy (PRK)

Visual acuity and contrast sensitivity after posterior lamellar keratoplasty

Visual function of police officers who have undergone refractive surgery

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