Three-year Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study

Culbertson, William W.; Lindstrom, Richard; McDonald, Marguerite B.; Kaufman, Herbert E.; Barron, Bruce; Lindstrom, Richard L.; Doughman, Donald J.; Nelson, J. Daniel; Obstbaum, Stephen A.; Asbell, Penny A.; Balyeat, Hal D.; Salz, James J.; Myers, William D.; Arends, Robert C.; Cowden, John W.; Stephenson, Robert L.; Fecko, Paul; Roust, Jerry; Laibson, Peter R.; Arentsen, Juan J.; Naidoff, Michael A.; Cohen, Elisabeth J.; Rowsey, J. James; Cartwright, Ceretha S.; McCulley, James P.; Stark, Walter J.; Thoft, Richard A.; Aquavella, James V.; Baum, Jules; Hardy, Robert J.; Krachmer, Jay H.; Sperduto, Robert D.; Sugar, Joel; Ware, James H.; Waring, George O.; Lynn, Michael

doi:10.1016/s0161-6420(87)80021-0

Cited by 98 publications

(23 citation statements)

References 37 publications

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“…1 Though the process of accommodation allows a number of these individuals to see normally without refractive correction, many others require spectacle, contact lens, or surgical correction, with the attendant risk of bacterial keratitis 2 or infection due to surgical correction of refractive error. [3][4][5] Additionally, children with high levels of hyperopia are at risk for accommodative esotropia, a condition that, if untreated, may result in amblyopia, impaired stereoscopic vision, and a significant reduction in vision-related functional status. 6 Although the number of children with accommodative esotropia is not well known, strabismus has been estimated to affect between 0.5% and 4% of children.…”

mentioning

confidence: 99%

Familial aggregation of hyperopia in an elderly population of siblings in Salisbury, Maryland

Wojciechowski¹,

Congdon²,

Bowie³

et al. 2005

Ophthalmology

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Purpose-To determine whether hyperopia aggregates in families in an older mixed-race population.Design-Cross-sectional familial aggregation study using sibships.Methods-We recruited 759 subjects (mean age, 73.4 years) in 241 families through the population-based Salisbury Eye Evaluation study. Subjects underwent noncycloplegic refraction if best-corrected visual acuity (BCVA) was ≤20/40, had lensometry to measure their currently worn spectacles if BCVA was >20/40 with spectacles, or were considered to be plano (refraction of zero) if the BCVA was >20/40 without spectacles. Preoperative refraction from medical records was used for bilaterally pseudophakic subjects.Results-Utilizing hyperopia cutoffs from 1.00 to 2.50 diopters, age-, race-, and gender-adjusted odds ratios for hyperopia with an affected sibling ranged from 2.72 (95% confidence interval [CI], 1.84-4.01) to 4.87 (95% CI, 2.54-9.30). The odds of hyperopia increased with age until 75 years, after which they remained relatively constant. Black men were significantly less likely to be hyperopic than white men, white women, or black women.Conclusions-Hyperopia appears to be under strong genetic control in this older population.Hyeropia, or farsightedness, describes the refractive state where the focal point of light entering the eye is behind the retina, due to a short axial length relative to the eye's optical system. Hyperopia of >3.0 diopters (D) is estimated to affect 11.8 million persons over the age of 40 years in the United States, or 9.9% of the U.S. population. 1 Though the process of accommodation allows a number of these individuals to see normally without refractive correction, many others require spectacle, contact lens, or surgical correction, with the attendant risk of bacterial keratitis 2 or infection due to surgical correction of refractive error. [3][4][5] Additionally, children with high levels of hyperopia are at risk for accommodative esotropia, a condition that, if untreated, may result in amblyopia, impaired stereoscopic vision, and a significant reduction in vision-related functional status. 6 Although the number of children with accommodative esotropia is not well known, strabismus has been estimated to affect between 0.5% and 4% of children. [7][8][9][10] Esodeviations comprise >50% of this, 11 with refractive accommodative esotropia clearly playing a significant role. Evidence exists suggesting that hyperopia may be under strong genetic control. 14,15 Twin studies in England have suggested that hyperopia, treated as a binary trait, has a heritability of 89%, virtually the same as myopia. 14 Biometric traits such as axial length and radius of corneal curvature, which determine hyperopia, also demonstrated heritability in the 80% to 90% range in the British twin study. However, genetic studies of hyperopia have been far fewer than for myopia. A small number of genetic conditions have been identified that are characterized by hyperopia in conjunction with ocular 16 or systemic 17 abnormalities. To the best of our knowledge...

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mentioning

confidence: 99%

Familial aggregation of hyperopia in an elderly population of siblings in Salisbury, Maryland

Wojciechowski¹,

Congdon²,

Bowie³

et al. 2005

Ophthalmology

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“…The PERK study extensively described the results of this type of refractive surgery. [9][10][11][12] In the study, 34% of patients reported difficulties with daily fluctuations of vision 1 year postoperatively. 1 The daily fluctuation was measured objectively by visual acuity, corneal curvature, and refractive error.…”

Section: Discussionmentioning

confidence: 87%

“…Indeed, our patient presented the 2 types of long-term changes in refraction that have been reported after RK: diurnal fluctuation and hyperopic shift. [9][10][11][12] The surgical way to treat overcorrection is to suture the wound tightly, thereby reversing the effect of the RK. In both eyes of our patient, the RK incisions were opened during insertion of the Intacs and had to be sutured postoperatively.…”

Section: Discussionmentioning

confidence: 99%

Intacs to stabilize diurnal variation in refraction after radial keratotomy

Koppen¹,

Gobin²,

Tassignon³

2007

Journal of Cataract and Refractive Surgery

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We present a patient who was dissatisfied with the refractive results of the radial keratotomy procedure he had 8 years previously, specifically the instability of the visual acuity and refractive error throughout the day. To reverse the biomechanical disturbance caused by the incisions, an intracorneal ring segment (Intacs, Addition Technology, Inc.) was inserted in the inferior cornea. The variation in refraction decreased from 1.50 and 2.25 diopters (D) to 0.25 and 0.50 D, resulting in a very satisfied patient.

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“…In addition, the repeatability, as well as the discriminative ability of those glare tests that have been studied were often found to be inadequate [24,39]. Because of these deficiencies, a standard method of glare measurement has never been adopted, as discussed in several papers [25,34,[43][44][45][46][47][48][49][50][51][52].…”

Section: Introductionmentioning

confidence: 99%

Computer Measurement of Central Visual Acuity under Mesopic and Glare Conditions in Eyes with Nuclear Cataract

Gutstein¹,

Sinclair²,

Presti³

et al. 2015

J Comput Sci Syst Biol

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BackgroundCataract lens opacification and color changes, occurring with age [1,2] and with systemic or ocular disease [3][4][5], world-wide have become the most common cause of visual complaints, primarily of glare and reduced contrast for multiple tasks in bright as well as dim light. Central visual acuity (VA), as measured by high contrast charts, has been demonstrated to be a poor determinant of visual function as well as patient complaints in eyes with significant cataract changes [6]. Patients having a cataract may demonstrate good visual acuity, whereas the contrast sensitivity testing demonstrates impairment even at early stages of the cataract development [3][4][5][7][8][9], especially when the eye is tested with off-axis glare. Bailey [10] and Lasa et al. [5] tested patients with cataracts using the Pelli-Robson and Vistech contrast sensitivity charts and reported that while both appear to evaluate visual function in moderate to advance cataracts, for early cataracts they and others [11] suggested that other techniques need to be developed including methods that utilize different luminance environments and off-axis glare elements in order to understand the range of visual disability under the varying environment conditions commonly presented during day and evening activities.As the lens ages there is a linear increase in lens opalescence and absorption of light, especially for blue light [12][13][14][15][16]. The increased absorption by the lens reduces retinal illumination and the opalescence increases diffraction and forward scatter, causing reductions in contrast sensitivity and colour discrimination [17]. A loss of contrast sensitivity has been observed with brunescence or opalescence of the lens causing loss primarily in the middle and high spatial frequencies [12]. This causes greater difficulty in vision under unfavourable lighting conditions especially at dusk where older individuals require higher contrasts to recognize and differentiate objects [10,18,19]. In addition, whereas the pupil diameter of a healthy 20-year-old on average is 5.3 mm in dim illumination, the pupil of a 60-year-old typically has a diameter of 3.2 mm [20] resulting in one third of the retinal illumination in dim environments. Contrast sensitivity testing has been demonstrated to remain stable until the age of approximately 65 years beyond which it and overall visual function decline rapidly [12,19], thought primarily due to senile miosis and progressive nuclear sclerosis, as well as with the aging of neural elements, both retinal and brain [20].The increased opalescence of the lens with cataract development results in increased forward light scatter [21] that produces a veiling Abstract Purpose: The CVA is an interactive, automated computer device that rapidly thresholds central acuity under conditions mimicking customary photopic and mesopic activities. In sequence, the CVA may test up to 6 environments, in this series under 3 mesopic environments (98%, 50% MC against 1.6 cd/m 2 background, 25% MC against 5 cd/m 2 ), the...

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Three-year Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study

Cited by 98 publications

References 37 publications

Familial aggregation of hyperopia in an elderly population of siblings in Salisbury, Maryland

Familial aggregation of hyperopia in an elderly population of siblings in Salisbury, Maryland

Intacs to stabilize diurnal variation in refraction after radial keratotomy

Computer Measurement of Central Visual Acuity under Mesopic and Glare Conditions in Eyes with Nuclear Cataract

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