Regarding the surgical reversal of presbyopia (SRP) surgery for presbyopia, vol 108, number 12, December 2001, 2161-2.
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Accommodation, Ocular↗
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Regarding the surgical reversal of presbyopia (SRP) surgery for presbyopia, vol 108, number 12, December 2001, 2161-2.
Explore the source record for details and available documents.
Accommodation, Ocular↗
A study of racial differences in age at onset and progression of presbyopia.
BACKGROUND: This study investigated reported differences in age at onset and progression of presbyopia between black and white patients. METHODS: The records of 692 primary care patients (242 black and 450 white), ages 35 to 55 years, who received eye examinations at the University of Alabama at Birmingham School of Optometry (December 1, 1992 and May 31, 1993), were reviewed retrospectively. Regression models were used to compare age at onset and progression of presbyopia of study subjects with respect to race. Also, the effect of socioeconomic status (SES) was assessed for a subset of 373 subjects. RESULTS: No significant differences in the age at onset or progression of presbyopia were detected between black and white patients (p > 0.05). Similarly, there were no significant differences in age at onset and progression of presbyopia with respect to socioeconomic status. CONCLUSIONS: Contrary to previous studies, the onset and progression of presbyopia of black and white patients in this study population did not differ significantly. This result suggests other factors may play a role in previously reported variation of presbyopia in black and white patients. Similarly, variations in income status did not significantly impact the onset and progression of presbyopia. Further study is needed to corroborate or refute these findings.
Adult↗
Associations of presbyopia with vision-targeted health-related quality of life.
OBJECTIVE: To evaluate the associations of presbyopia and its correction, particularly monovision optical correction, with vision-targeted health-related quality of life. METHODS: The National Eye Institute Refractive Error Quality of Life (NEI-RQL) Instrument was prospectively self-administered by subjects from 6 medical centers in the following age and correction categories: subjects with emmetropia younger than 45 years (n = 75), subjects with emmetropia aged 45 years or older (n = 38), and subjects with ametropia aged 45 years or older without monovision (n = 486) or corrected with monovision (n = 38). Differences in the 13 NEI-RQL Instrument subscale scores among subjects in the 4 groups were examined. The age of 45 years or older was used as a surrogate for presbyopia. RESULTS: A comparison of older (age > or =45 years) vs younger (age <45 years) persons with emmetropia suggests that presbyopia was associated with reduced scores in 7 of 13 subscales (P<.05). In those aged 45 years or older, correction of presbyopia with monovision was associated with statistically significantly better scores on 3 subscales (expectations, dependence on correction, and appearance) compared with single-vision correction. One subscale (dependence on correction) showed worsening scores with increasing age without adjustment for need or type of correction. Older persons with monovision correction had significantly worse scores than younger subjects with emmetropia on all subscales except suboptimal correction and appearance. CONCLUSIONS: Presbyopia is associated with worse vision-targeted health-related quality of life compared with younger subjects with emmetropia. Monovision correction of presbyopia is related to some improvements in health-related quality of life, but it is still worse than that for younger subjects with emmetropia in several areas.
Adult↗
The mechanism of presbyopia.
Accommodation in humans refers to the ability of the lens to change shape in order to bring near objects into focus. Accommodative loss begins during childhood, with symptomatic presbyopia, or presbyopia that affects one's day to day activities, striking during midlife. While symptomatic presbyopia has traditionally been treated with reading glasses or contact lenses, a number of surgical interventions and devices are being actively developed in an attempt to restore at least some level of accommodation. This is occurring at a time when the underlying cause of presbyopia remains unknown, and even the mechanism of accommodation is occasionally debated. While Helmholtz' theory regarding the mechanism of accommodation is generally accepted with regard to broad issues, additional details continue to emerge. Age-related changes in anterior segment structures associated with accommodation have been documented, often through in vitro and/or rhesus monkey studies. A review of these findings suggests that presbyopia develops very differently in humans compared to non-human primates. Focusing on non-invasive in vivo human imaging technologies, including Scheimpflug photography and high-resolution magnetic resonance imaging (MRI), the data suggest that the human uveal tract acts as a unit in response to age-related increasing lens thickness and strongly implicates lifelong lens growth as the causal factor in the development of presbyopia.
Accommodation, Ocular↗
Southeastern Asian refugees' presbyopia.
The onset and terminal stages of presbyopia, the loss of amplitude of accommodation of the eye associated with old age, of the Southeastern Asian refugees were investigated. Subjects examined in a 6-mo. period in an optometric practice are included. A +1.00 D add was used to define onset of presbyopia, and +2.00 to 2.50 D, the terminal stage. Only those age 42 yr. and below were analyzed, a total of 184 subjects. Of these 68 required a +1.00 D or larger add. chi 2 test of an obvious increase in add requirement from ages 30-34 to 35-39 yr. was significant, meaning that the onset of presbyopia begins at the age of 35 yr. Age 42 yr. was considered the most probable age to be the terminal stage. An unusual feature, presbyopia occurring below age 35 yr., was noted. Thus, the earlier onset and terminal stages of presbyopia of the Southeastern Asian refugees support the notion of the regional, ethnic, and environmental influences in the development of presbyopia.
Adolescent↗
The aetiology of presbyopia: a summary of the role of lenticular and extralenticular structures.
Presbyopia is a condition of age rather than ageing and, as such, is devolved from the lamentable situation where the normal age-related reduction in amplitude of accommodation reaches a point when the clarity of vision at near cannot be sustained for long enough to satisfy an individual's requirements. Most of our facility to accommodate has been lost by 55 years-of-age and subsequent deterioration in visual performance at near is attributable to characteristics of senescent vision familiar to the optometrist. Our understanding of the cause of presbyopia has then to be derived principally from our understanding of the mechanism of accommodation in young eyes. Hermann von Helmholtz did much to clarify these mechanisms, but despite much research in the 100 years since his death, there is still no consensus on their precise nature. This paper presents a summary of issues, past and present, which have figured in the literature on the physiology of accommodation and presbyopia, and confirms that the pathophysiology of presbyopia is likely to result from deterioration in structure and function of a number of inter-related tissues. Changes in crystalline lens dimensions with age, the associated change in geometry of zonular attachments, and changes in viscoelastic properties of the lens capsule and lens matrix would, however, appear to be the principal correlates for the onset of presbyopia. Recent models of the biomechanics of accommodation have drawn attention to the feasibility of extralenticular contributions to presbyopia and have examined properties of the elasticity and leverage provided by posterior, anterior and tensile fibre systems.(ABSTRACT TRUNCATED AT 250 WORDS)
Accommodation, Ocular↗
A retrospective study on presbyopia onset and progression in a Hispanic population.
BACKGROUND: This study evaluates differences in age and presbyopia progression between an ethnic Hispanic and a non-Hispanic patient population. METHODS: Patient records from the Optometric Center of Los Angeles were examined retrospectively from 1998 through 2001. The first part of the study compared ages at onset and progression of presbyopia as a function of ethnicity. The second part of the study compared the amplitude of accommodation for the cohort of patients to Hofstetter's expected norms. RESULTS: A total of 332 patient records were evaluated: 61% (n = 203) Hispanic and 39% (n = 129) non-Hispanic. For an add power of +0.75 D, presbyopia developed in the reviewed Hispanic population at 39.31 years of age in comparison to development in non-Hispanics at 40.22 years. Hispanics also had a similar progression of reading add power (0.105 D/year) as compared to non-Hispanics (0.097 D/year) (t= 0.798, p = 0.43). The progression of amplitude of accommodation for the Hispanic (amplitude = 11.2 - 0.132 x age) and non-Hispanic populations (amplitude = 9.72 - 0.18 x age) (t= 0.0997, p = 0.92) were comparable, but both groups show a slower decline of amplitude when compared to Hofstetter's norms (p< 0.001). CONCLUSIONS: No statistically significant difference in the age at onset and progression of presbyopia was found between Hispanic and non-Hispanic patients; however, both groups of patients have a later onset and slower progression of presbyopia when compared to Hofstetter's norms.
Adult↗
Correlation between presbyopia, age and number of births of mothers in the Kumasi area of Ghana.
There is an assumption in Ghana that motherhood has an effect on presbyopia. This study thus attempts to correlate the relationship between presbyopia, age and number of births of mothers in the Kumasi area of Ghana. The data were compiled from records of patients who attended routine eye examinations and refraction tests at the Morny Optical Centre, Kumasi, during the last quarter of 1993. Presbyopia in males and females, and those of mothers and childless female adults for particular age groups were compared. Correlations were found between age and reading additions for both sexes, and presbyopia occurs at a younger age than published. This preliminary study does not indicate any inter-dependence of births on female presbyopia. Further studies with select data may be required to confirm the above findings.
Adolescent↗
Myopic astigmatism and presbyopia trial.
PURPOSE: No prospective double-masked study has evaluated whether low astigmatism benefits or harms patients with presbyopia, whose intermediate and near vision might theoretically benefit from enhanced depth of focus provided by astigmatism. The purpose of the first Myopic Astigmatism and Presbyopia (MAP I) study was to determine whether low myopic astigmatism enhances or harms the visual acuity, stereopsis, or quality of life in patients with presbyopia. DESIGN: Prospective, randomized, double-masked, crossover design clinical trial. METHODS: Fifteen patients with presbyopia aged 45 to 68 years were recruited from an academic center population. These patients were given a baseline eye examination, including manifest refraction, Early Treatment of Diabetic Retinopathy Study (ETDRS) logarithm of minimal angle of resolution (logMAR) visual acuity at distance, intermediate, and near, accommodative amplitudes, and stereo vision. Each patient was then cycled in random order through three masked pairs of soft contact lenses. The power of each contact lens pair was calculated by the subtraction method to maintain a spherical equivalent of -0.5 diopters, while providing either no astigmatism (spherical arm, SPH), 1 diopter of with-the-rule (WTR) astigmatism, or 1 diopter of against-the-rule (ATR) astigmatism. Actual refractive errors produced were measured by masked examiner. Outcomes measured at the end of 1 week of usage of each contact lens arm were binocular (ETDRS) logMAR visual acuity at three distances (far [4 m], intermediate [1 m], and near [33cm]); near stereoacuity, using the quantitative Titmus Stereotest; and quality of life, measured using the Refractive Status and Vision Profile (RSVP), a standardized questionnaire. RESULTS: Visual acuity results across the three arms were similar. However, 1-m logMAR visual acuity was better for the spherical arm than either astigmatic arm (-0.06 SPH, +0.01 WTR, +0.02 ATR). Near (33 cm) and distance (4 m) acuities were similar across arms. Stereoacuity was better in ATR than WTR (50 vs 102 seconds, P =.01). Subjects preferred SPH slightly over the WTR astigmatic arm by the RSVP quality-of-life survey instrument (101 vs 104, P =.05). Other intergroup comparisons showed no difference in RSVP scores. CONCLUSIONS: This study has demonstrated that intermediate distance acuity and refractive quality of life are slightly better with spherical low myopic refractive error vs either astigmatic arm. Near and far distance acuity were unaffected by low myopic astigmatism compared with spherical low myopia. Near stereopsis was best in the ATR arms, but this did not produce better near visual acuity or RSVP quality of life.
Aged↗
Accommodation and presbyopia.
The mechanism of accommodation has been studied for at least four hundred years. The most interesting aspect of accommodation is that its time course is well in advance of other physiological functions--it begins to decline by adolescence and is lost about two-thirds of the way through the normal life span. The state of presbyopia is reached when accommodation has declined sufficiently to interfere with close tasks requiring acute vision. Presbyopia is generally considered to originate with the 'plant' of the accommodative system, either within the lens and its capsule or within their support structures. One of the lenticular theories, the Hess-Gullstrand theory, is distinguished from other theories by its claim that as age increases there is an increasing excess amount of ciliary muscle contraction beyond the ability of the lens and capsule to respond to it. For all other theories, the maximum possible amount of ciliary muscle contraction is always necessary to produce maximum accommodation, at least beyond the age at which it reaches its peak. From my review of the present understanding of the mechanisms of accommodation and the theories of the development of presbyopia, I conclude that there is overwhelming evidence against the Hess-Gullstrand theory and that it is unlikely that changes in the ciliary muscle contractility contribute significantly to the development of presbyopia.
Accommodation, Ocular↗
The effect of incipient presbyopia on the correspondence between accommodation and vergence.
PURPOSE: To investigate the accommodation-convergence relationship during the incipient phase of presbyopia. The study aimed to differentiate between the current theories of presbyopia and to explore the mechanisms by which the oculomotor system compensates for the change in the accommodation-convergence relationship contingent on a declining amplitude of accommodation. METHODS: Using a Canon R-1 open-view autorefractor and a haploscope device, measurements were made of the stimulus and response accommodative convergence/accommodation ratios and the convergence accommodation/convergence ratio of 28 subjects aged 35-45 years at the commencement of the study. Amplitude of accommodation was assessed using a push-down technique. The measurements were repeated at 4-monthly intervals over a 2-year period. RESULTS: The results showed that with the decline in the amplitude of accommodation there is an increase in the accommodative convergence response per unit of accommodative response and a decrease in the convergence accommodation response per unit of convergence. CONCLUSIONS: The results of this study fail to support the Hess-Gullstrand theory of presbyopia in that the ciliary muscle effort required to produce a unit change in accommodation increases, rather than stays constant, with age. Data show that the near vision response is limited to the maximum vergence response that can be tolerated and, despite being within the amplitude of accommodation, a stimulus may still appear blurred because the vergence component determines the proportion of available accommodation utilised during near vision.
Accommodation, Ocular↗
Presbyopia toward the end of the 20th century.
Recent advances in our understanding of the anatomy and physiology of accommodation have contributed to current concepts of the possible constituent factors in presbyopia, largely supplanting the long-held belief that presbyopia is due to sclerosis of the crystalline lens. In this review, the author examines epidemiologic, basic scientific, and clinical evidence for a multifactorial decrease in accommodative amplitude with age. Methods of measurement, oculomotor effects of presbyopia, and approaches to correcting it are also considered.
Accommodation, Ocular↗
Presbyopia correction with an anterior chamber phakic multifocal intraocular lens.
PURPOSE: To investigate in a pilot study the potential of an anterior chamber phakic refractive multifocal intraocular lens (IOL) prototype for the correction of near and far vision in those with myopic and hyperopic presbyopia. DESIGN: A multicenter, open-label, prospective, noncomparative pilot evaluation. PARTICIPANTS: There were 17 patients (34 eyes), 16 women and 1 man, with a mean age of 52+/-3.94 years (range, 46-62 years). Six eyes were myopic (mean spherical equivalent [SE], -9.3+/-3.83 diopters (D)) and 28 were hyperopic (mean SE, +2.3+/-0.77 D), with astigmatism less than 1.5 D. METHODS: The prototype multifocal phakic IOL was implanted through a 6.5-mm temporal incision. The dominant eye was targeted for emmetropia and the nondominant eye for -1.0 D. MAIN OUTCOME MEASURES: The efficacy of the implant was assessed after surgery by measuring monocular and binocular uncorrected and distance-corrected visual acuity (VA) at distance, intermediate, and near, and distance-corrected near VA with near add. Distance-corrected distance and near VA also were determined in low contrast (25%). The safety index and efficacy index were calculated, and patient satisfaction questionnaires also were administered. Follow-up was at 1-3 days, 5-9 days, 21 days, 3 months, 6 months, and 1 year after surgery. RESULTS: Spherical equivalent refraction ranged from -11.75 to +4.25 D before surgery, and from -2.0 to +1.85 D 1 year after surgery. The binocular efficacy index was 0.68 (near) and 1.0 (distance), and the binocular safety index was 1.0 for both near and distance. Mean binocular uncorrected distance VA improved from 20/59 (+/-4 lines) before surgery to 20/18 (+/-1 line) 1 year after surgery. Mean binocular uncorrected intermediate VA improved from 20/125 (+/-10 lines) to 20/21 (+/-1 line), and mean binocular uncorrected near VA improved from 20/78 (+/-5 lines) to 20/32 (+/-1 line). Binocular uncorrected visual acuity was at least 20/40 (distance and intermediate) and Jaeger 3 in 88.2% of patients, and it was at least 20/40 and Jaeger 5 in 100% of patients. Patient satisfaction was very good in 88% of patients (15 of 17); the remaining 2 patients reported moderate satisfaction. CONCLUSIONS: Promising results were obtained with the refractive multifocal phakic IOL prototype investigated in this pilot study for near and far visual correction in presbyopia associated with myopia and hyperopia. Multifocal phakic intraocular optics may be an option for presbyopia correction.
Adult↗
Presbyopia complicating pre-existing strabismus.
BACKGROUND: Presbyopia may affect pre-existing sensory adaptations or aggravate previously asymptomatic heterophoria. We describe the presentation, underlying problem and management of 11 patients with pre-existing strabismus or heterophoria who presented with new symptoms of double vision attributable to presbyopic change, an association not previously reported. METHODS: Patients with new strabismic symptoms attributable to presbyopia were recruited prospectively over a 1-year period. RESULTS: The 11 patients had had a recent decrease of accommodative amplitude that resulted in blurred vision at near with a breakdown of pre-existing heterophoria (2 patients), alteration of fixation pattern (6 patients), symptomatic alternating fixation (2 patients) or intolerance to correction owing to restrictive strabismus (1 patient). INTERPRETATION: At the onset of presbyopia, symptoms may be varied and subtle. Ophthalmologists and orthoptists should carefully determine the exact nature of the symptoms. Any pre-existing fixation pattern should then be established from the history, old photographs or suppression characteristics. Refractive or surgical management should be aimed at returning the patient to his or her long-standing sensory adaptation. Other important issues, such as incomplete correction of hypermetropia by refractive surgery and problems using bifocals with vertical restrictive strabismus, should be noted.
Accommodation, Ocular↗
Static aspects of accommodation: age and presbyopia.
Although the progressive reduction in accommodative amplitude with increased age is well documented, little is known about several other aspects of static or steady-state accommodation to provide a comprehensive assessment of changes related to age and presbyopia. Static components of accommodation (tonic accommodation, depth-of-focus, slope of the stimulus/response function, and accommodative controller gain) were assessed objectively using an infrared (IR) optometer in 30 human subjects aged 21-50 years; depth-of-focus was also determined psychophysically as was accommodative amplitude. Tonic accommodation and the amplitude of accommodation decreased with increased age, whereas the subjective depth-of-focus increased; the other parameters remained unchanged. The decrease in tonic accommodation and amplitude of accommodation was attributed to biomechanical factors, whereas the increase in subjective depth-of-focus was believed to result from increased tolerance to defocus related to the gradual onset of presbyopia. Constancy of the objective depth-of-focus suggested absence of age effects on the neurologic control of reflex accommodation, whereas the lack of systematic change in slope and controller gain provided support for the Hess-Gullstrand theory of accommodation and presbyopia.
Accommodation, Ocular↗
The mechanics of accommodation in relation to presbyopia.
The cause of presbyopia is closely related to the force of contraction of the ciliary muscle and the resistance to deformation of the crystalline lens. Two views are currently in conflict. The view of Donders (1864) that presbyopia is caused by a decrease in the force of contraction of the ciliary muscle with age, and the opposing view of Helmholtz (1855) that the lens becomes more difficult to deform with age due to lenticular sclerosis. The present paper shows that, in fact, the ciliary muscle undergoes a compensatory hypertrophy as accommodative amplitude decreases with age. The force of contraction is about 50% greater at the onset of presbyopia than in youth. However, because of increased lenticular resistance its effect on the amplitude of accommodation is small. It is shown that the reason the lens becomes more difficult to deform is not because of lenticular sclerosis, since the lens substance does not lose water. The increased difficulty of deformation is because the capsule loses its elastic force with age and the lens fibres, particularly in the nucleus, become more compacted.
Accommodation, Ocular↗
[Effects of presbyopia on clinical phoria].
BACKGROUND: Due to accommodation-vergence cross-link we can expect that presbyopia will affect vergence as well. From investigations of cross-link as function of age one may assess strain of visual system due to presbyopia. Furthermore, this observation will give hints on innervation of ciliary muscle. MATERIAL AND METHOD: Vergence is assessed as function of stimulus of accommodation in 27 subjects (24-65 years). RESULTS: Presbyops tend to be exophoric for near vision. Vergence is linked to accommodation by means of a quadratic polynome rather than by a linear function. CONCLUSIONS: We may expect, that missing vergence strains visual system of presbyops. Results support Hess-Gullstrand theory of presbyopia and indicate a loss of innervation of ciliary muscle with increasing age.
Accommodation, Ocular↗