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PubMed1989

Diminished foveal sensitivity may predict the development of advanced age-related macular degeneration.

Visual function testing was performed on one eye with drusen from each of 18 elderly patients in 1984. Eleven patients had advanced age-related macular degeneration (AMD) in the fellow eye, and seven had only bilateral drusen. These patients were all followed prospectively (median, 45 months), at which time one eye had a new vessel membrane, three eyes had pigment epithelial detachments, and one eye had geographic atrophy. Only two of these five eyes had AMD-related visual loss in the fellow eye in 1984. The degree of loss of foveal dark-adapted sensitivity in 1984 predicted which patients developed advanced AMD with 100% sensitivity and 92% specificity. The presence of high-risk drusen characteristics in 1984 predicted the development of advanced AMD with 100% sensitivity but only 55% specificity. For this small group of patients, foveal dark-adapted sensitivity loss was an excellent predictor of the subsequent development of advanced AMD in eyes with drusen. A prospective study of a large group of patients with drusen is being undertaken to validate this finding.

Aged↗
PubMed2005

[Comparison of high-order optical aberrations induced by different multifocal contact lens geometries].

PURPOSE: To analyze the effects of different multifocal soft contact lens geometries on high-order ocular optical aberrations. MATERIALS AND METHODS: Thirty nonpresbyopic eyes were fitted with eight multifocal contact lenses: Soflens Multifocal High, Soflens Multifocal Low, Focus progressive, Acuvue Bifocal Add +2.00, Rythmic Multifocal Profile 1, Rythmic Multifocal Profile 2, Proclear D Add 2.00, Proclear N Add 2.00. All these contact lenses corrected the ametropia for far distance. The ocular aberrations were measured with and without each contact lens using a Hartmann-Shack aberrometer, (Zywave from Bausch and Lomb) successively after pupil dilation with one or two drops of Neo-Synephrine and wavefront decomposition in Zernike polynomials up to the 5th order. RESULTS: Odd and even aberrations increased for all the tested multifocal soft contact lenses. The most significant increase was noted for the a(4.0) Zernike coefficient. The mean value of a(4.0) without contact lens was -0.178+/-0.121 microm. The contact lenses having a central zone for near addition cause the inversion of the sign of the a(40) coefficient The central far vision contact lens leads to the opposite effect, increasing spherical positive aberrations. The most significant increase in total high-order ocular aberrations were noted for Proclear D soft contact lenses (0.396+/-0.109 microm without contact lens, 0.511+/-0.123 microm with contact lens; p<0.05, +29%), for Proclear N soft contact lenses (0.396+/-0.109 microm without contact lens, 0.568+/-0.165 microm with contact lens; p<0.05 +43%) and for Acuvue Bifocal soft contact lens (0.396+/-0.109 microm without contact lens, 0.567+/-0.162 microm with contact lens; p<0.05 +43%). CONCLUSION: Wearing multifocal contact lenses induces an increase in high-order ocular aberrations. The location of the near addition zone is related to the sign of the variation of the a(4.0) coefficient. The central near vision multifocal contact lenses seem to induce large amounts of negative spherical aberrations. The far vision contact lenses seem to induce an increase in positive spherical aberrations. The relative decentration of the lens to the pupil may explain the increase in odd high-order aberrations. These results might be useful to understand the visual complaints of patients fitted with multifocal contact lenses.

Contact Lenses↗
PubMed2002

Refractive lens exchange with the array multifocal intraocular lens.

PURPOSE: To study the safety and efficacy of refractive lens exchange as a refractive surgery modality in the presbyopic population. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: This retrospective review of patient charts included patient selection, preoperative evaluation, management of astigmatism, surgical technique, postoperative visual outcome, and complications. The study included 68 eyes comprising 32 bilateral and 4 unilateral refractive lens exchanges. RESULTS: All patients having bilateral refractive lens exchange achieved an uncorrected binocular visual acuity of 20/40 and J5 or better 1 to 3 months postoperatively. More than 90% achieved an uncorrected binocular visual acuity of 20/30 and J4 and nearly 60%, of 20/25 and J3. CONCLUSION: Refractive lens exchange was a safe and effective refractive surgery modality in presbyopic patients.

Aged↗
PubMed1995

Small-diameter corneal inlay in presbyopic or pseudophakic patients.

We report the results of using the small-diameter corneal inlay to create a bifocal cornea. The inlay was implanted in five eyes in January 1993. At 12 months postoperatively, uncorrected near vision had improved from J4 to better than J2 in four of the five. The results indicate that the corneal inlay improves near vision and is compatible within the cornea.

Adult↗
PubMed1999

Binocular function and patient satisfaction after monovision induced by myopic photorefractive keratectomy.

PURPOSE: To measure binocular function and patient satisfaction with monovision induced by photorefractive keratectomy (PRK) in myopic presbyopic patients. SETTING: Refractive Department, Cleveland Clinic, Cleveland, Ohio, USA. METHODS: This study comprised 21 myopic presbyopic patients with monovision induced by PRK. Sixteen emmetropic patients who had PRK served as a control group. Monovision was induced by undercorrecting the nondominant eye by 1.25 diopters for near vision and correcting the dominant eye with emmetropia for distance vision. Monocular and binocular uncorrected Snellen visual acuities at 20 feet and 13 inches, manifest refraction, ocular dominance, stereopsis at 20 feet and 13 inches, monocular and binocular contrast sensitivities, Worth-4-Dot test at 20 feet and 1/3 of a meter, and fusional convergence amplitudes were examined in each patient. RESULTS: In the monovision group at near and distance, 20 patients (95.3%) had binocular visual acuity of 20/25 or better. No patient in the monovision group used reading glasses postoperatively; 4 of 16 patients (25.0%) in the control group used such glasses. All patients maintained binocular fusion and stereo acuity ranging from 40 to 800 seconds of arc. Mean patient satisfaction was 86% (range 40% to 100%). In the control group, 12 patients (75.0%) had binocular distance visual acuity of 20/25 or better and 11 (68.8%) had binocular near visual acuity of 20/25 or better. CONCLUSION: Monovision PRK patients had better near vision than control PRK patients, with minimal compromise in stereo acuity and overall high patient satisfaction.

Adult↗
PubMed2003

Presbyopic correction with contact lenses.

According to Paragon Vision Sciences (Mesa, AZ), an additional 50,000 Americans become presbyopic each day. There are many contact lens options available to help these patients meet their visual needs in the workplace and for recreational and social activities. Although technology still requires some compromise on the part of many patients, constant advances in materials and designs should enable even greater numbers of presbyopes to enjoy the freedom of functioning without glasses in the years to come.

Contact Lenses↗
PubMed2004

Progressive addition lenses--matching the specific lens to patient needs.

BACKGROUND: The objective of this study was to use state-of-the-art methods to measure the optical characteristics of commonly available progressive addition lenses (PALs) and to develop derivatives of the optical measurements that can be used as guidelines in selection of lenses based on patients' visual needs. METHODS: The optics of 28 PALs currently on the market were measured with a Rotlex Class Plus lens analyzer. PALs were specified with plano distance power and a near add of +2.00 D. Data were normalized to plano at the location specified by each manufacturer and acquired from each data file in 1-mm vertical steps with respect to the fitting cross. RESULTS: The variance across lenses was greater than 2:1 for most measurements. Ratings were calculated based on equal weighting of zone width and area for distance, intermediate, and near zones, and also for magnitude of unwanted astigmatism. CONCLUSIONS: The results demonstrate wide ranges of optical characteristics across the PALs tested in this study. Ratings of the distance, intermediate, and near zones, as well as rating of unwanted astigmatism can be used in selection of appropriate lenses to match patient visual needs.

Eyeglasses↗
PubMed1991

Diffractive bifocal contact lenses in aphakia and pseudophakia. A pilot study.

Diffractive bifocal contact lenses function by diverting incident light to two focal points. Light from near objects is focused by diffraction while that from distant objects is focused by conventional refraction. Both processes occur simultaneously throughout the full aperture of the lens. Fourteen aphakic and pseudophakic contact lens wearers were fitted with diffractive bifocal lenses and observed for an eight week period. Six (42.8%) were satisfied with the visual result. Five subjects (35.7%) discontinued lens wear complaining of poor quality of near vision. We conclude that these lenses may help selected aphakic patients to discard their reading glasses but the low acceptance rate suggests that this type of optic is probably not suitable for implantation as an intraocular lens.

Accommodation, Ocular↗
PubMed2001

Failure of accommodation in patients with HIV infection.

PURPOSE: The principal objective was to test the hypothesis that HIV-positive patients have significantly reduced amplitudes of accommodation compared with controls. The secondary objective was to investigate accommodative impairment in relation to factors such as age of susceptibility, CD4 count, viral load and current antiretroviral therapies. METHOD: The study was a single-center open prospective study involving a subject population of 43 HIV-positive men aged from 26 to 39 years with no previous history of eye problems and 21 age-matched healthy male controls. The main outcome measure was the amplitude of accommodation, as measured monocularly with a standard push-up technique. RESULTS: Amplitudes of accommodation were significantly smaller in the HIV-positive group compared with controls for age groups 25-29 (p = 0.016) and 30-34 years (p = 0.030) but not in the older group. In total, 30% (8/27) of patients aged between 25 and 34 years had reduced amplitudes of accommodation below age-expected norms. Accommodative failure was not related to current or lowest CD4 count, viral load or specific antiretroviral therapies. CONCLUSION: This study has identified accommodative failure in a significant proportion of HIV-positive patients aged between 26 and 35 years. This problem may be under-recognised, and further studies are warranted to investigate possible causes.

Accommodation, Ocular↗
PubMed2000

Association of presbyopic correction with changes in visual fields.

The purpose of this study was to investigate the effect of presbyopic correction on changes in visual fields caused by an alteration in outflow of aqueous humour Visual fields were compared before and after introduction of presbyopic correction in participants of the Melbourne Visual Impairment Project. Height and slope of the 'Hill of Vision' were assessed by calculating median thresholds in the four sets of three eccentric points. Analysis of 101 eyes in the study group and 101 eyes in the control group shows higher decrease of the 'Hill of Vision' height in the group of participants who started wearing presbyopic correction, than in the group without presbyopic correction (P = 0.02). Intraocular pressure measured irrespectively of participant's accommodative activity was not significantly different between the two groups at both time points. These data suggest that the use of presbyopic correction is associated with changes in the visual field.

Accommodation, Ocular↗
PubMed2001

Differences in the nearpoint of convergence with target type.

PURPOSE: The purpose of this study was to determine the effect on measurements of the nearpoint of convergence (NPC) of different target types. In order to assess the influence of accommodation, the NPC was also measured under conditions of varying accommodative demand. METHODS: The NPC was measured to the nearest 0.5 cm using three targets: the RAF rule, the sharpened tip of a pencil and the tip of the examiner's index finger. All measurements were performed under the same conditions on two groups of asymptomatic subjects, a group of 14 presbyopic subjects and a group of 14, younger, non-presbyopic subjects. The influence of accommodative demand was assessed in the non-presbyopic group by measuring the NPC while subjects viewed the RAF rule target through +2.00 and -2.00 lenses held in front of their eyes. RESULTS: For the presbyopic group, the NPC (break) and NPC (recovery) were independent of target type. However, the NPC (break) was significantly less remote than the NPC (recovery). Comparative data for the non-presbyopic group showed that NPC (break) for the RAF target was less remote than for either the pencil tip or finger tip targets. In agreement with the results from the presbyopic group, the NPC (recovery) was independent of target type. CONCLUSION: For subjects with little or no accommodation, the NPC does not depend on the target used and is the same measured with the RAF rule, a pencil tip or finger tip. In non-presbyopic subjects there appears to be a small accommodative influence on the NPC, which is target dependent. However, the difference is probably not clinically important.

Accommodation, Ocular↗
PubMed2003

Optical performance in eyes wearing two multifocal contact lens designs.

The optical performance of eyes wearing soft multifocal contact lenses was studied using the double-pass technique. Retinal image quality was measured in a group of six eyes wearing two different designs of multifocal lenses: an aspheric design and a spheric multicurve design. Measurements were performed for far, intermediate and near vision conditions and with two different pupil diameters: 3 and 5 mm. The results show that the best optical performance is obtained for far vision conditions when no lens is worn. For near vision conditions, the optical performance when the lens is worn is, in general, better than when no lens is worn. When the lens is worn, the optical performance for far and intermediate vision conditions is similar for the aspherical design, but it decreases for near vision conditions. For the spherical multicurve design, the optical performance obtained for far vision conditions is similar to that obtained for intermediate vision conditions for low values of object vergence, but decreases when the object vergence is high and therefore also for near vision. In general, the differences in optical performance are greater for small pupil diameters (3 vs 5 mm). The general trends of the results obtained by computing the modulation transfer function of the contact lens-eye system can also be shown qualitatively by means of double-pass images or quantitatively by computing the Imax/Imed of the image.

Adult↗
PubMed2001

[First results of implantation of a new, potentially accommodative posterior chamber intraocular lens].

PURPOSE: Conventional posterior chamber intraocular lenses (PCIOL) generally provide excellent visual acuity but do not restore accommodation. A new, potentially accommodative PCIOL has been designed after principles elaborated by K.D. Hanna using finite element models. However, before newly developed PCIOL may be implanted routinely in larger numbers of patients, careful and meticulous evaluation in clinical studies is necessary. Thus, it was the aim of this study to investigate intra- and early 3-month postoperative findings after implantation of the newly designed PCIOL. PATIENTS AND METHODS: In a prospective pilot and safety study that was approved by the ethics committee of our university, six eyes of six patients (2 males, 4 females, age range 54 to 87 years) with senile or presenile cataract underwent phacoemulsification and implantation of the new PCIOL by one surgeon between June and November 2000. The PCIOL (1 CU, HumanOptics AG, Erlangen, Germany) is a one-piece hydrophilic acrylic foldable lens with an optic diameter of 5.5 mm. Modified haptics are intended to allow anterior movement of the lens optic as a function of contraction of the ciliary muscle. Intra- and early postoperative findings obtained after one and two days, one, two and six weeks and 3 months postoperatively were documented prospectively. Postoperative examinations included recording of distance and near visual acuity both obtained with best distance correction, determination of subjective near point and measurement of distance and near refraction by streak retinoscopy. Follow-up was at least three months in all patients. RESULTS: Surgery was uncomplicated in all patients with successful in-the-bag implantation and good centration of the PCIOL. The postoperative course was uncomplicated without inflammation, hemorrhage, synechiae or decentration. Visual acuity improved in all patients according to the status of the macula with values between 20/200 (atrophic maculopathy) and 20/20. After three to six months we observed a difference between retinoscopic near and distance refraction of 0.625 to 1.875 D and subjective near points of 40 to 100 cm. Near visual acuity with distance correction ranged from 0.1 or J 16 (atrophic maculopathy) to 0.4 or J 7. CONCLUSIONS: These early and preliminary results of our small pilot study are encouraging. Our findings may indicate at least some degree of pseudophakic accommodation. However, further studies with additional methods of measurements, with longer follow-up, more patients and controlled studies with control groups are essential to further determine safety and potential accommodative power of this new PCIOL.

Accommodation, Ocular↗
PubMedDate not supplied

[Acceptance of progressive lenses].

BACKGROUND: The wearing of progressive lens poses a problem to two kinds of patients: those who are practically emmetropic and use reading glasses only, and ametropic patients whose eyes have been corrected for years with bifocals. The wearing of progressive lenses is generally not recommended for those presbyopes. METHODS: A group of individuals (n = 50) underwent refraction, and their addition was adjusted to their work and their age (44-72 years). They were then divided into two groups, one of which (n = 25) was equipped with bifocals (Telarc, Essilor) and the other (n = 25) with progressive lenses (Varilux Comfort, Essilor). After four weeks, the types of glasses were exchanged. After a further four weeks, each group used the original pair of glasses for another week. At the end of this phase, each of the test subjects was asked his opinion in favour of one or the other types of glasses. At each change of glasses, factors such as duration of the adaptation period, assessment of sight, general impression and time of use were recorded. RESULTS: At the determination of refraction much attention must be given to mildly astigmatic patients in order to optimise the prescription of progressive lenses. Progressive lenses were just as well tolerated by the group of convinced bifocal wearers, even though the familiarisation period took up to two weeks, especially for the older patients. Once the progressive lenses had been accepted, bifocals were generally abandoned for good. This is mainly due to the quality of the progressive lenses, which favour precise vision even in intermediate zones. For most of the individuals who were previously fitted with reading glasses only, the demarcation line between the distant and near parts of the bifocal lens pose major problems. Whereas progressive lenses were accepted as readily as in the group previously fitted with bifocals, about 40% of the total individuals tested refused bifocal lenses. CONCLUSION: In all, 96% of the participants considered progressive lenses good or very good. All recognised that progressive lenses represent the most aesthetic solution. However, in certain cases bifocal lenses together with progressive lenses remain interesting. For patients who were previously accustomed to reading glasses only, the duration of use of glasses with progressive lenses rose from 40% to 60% of the working day.

Adult↗