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PubMed2004

Photorefractive keratectomy followed by strabismus surgery for the treatment of partly accommodative esotropia.

PURPOSE: To evaluate photorefractive keratectomy (PRK) followed by bilateral medial rectus muscle recessions (BMR) to treat adults with partly accommodative esotropia. METHODS: We reviewed medical records of 10 consecutive patients with partly accommodative esotropia who underwent PRK to correct hyperopia followed 6 months later by BMR to treat the accommodative and nonaccommodative components of their esotropia, respectively. Visual acuity, spherical equivalent of refractive error, alignment, and sensory data were collected and analyzed. RESULTS: Twenty eyes of 10 patients were treated and followed for 1 year. PRK was successful in treating the hyperopia (mean post-PRK spherical equivalent was 0.14 D (SD = 0.22)) and the accommodative portion of the esotropia (the mean percentage of the distance accommodative component eliminated by PRK was 101.67% and the mean percentage of the near accommodative component eliminated by PRK was 115%). However, subsequent BMR using standard surgical tables based on the distance deviation to treat the post-PRK residual (nonaccommodative) esotropia resulted in uniform undercorrection. CONCLUSION: PRK may be useful to treat the accommodative portion of partly accommodative esotropia. Bilateral medial rectus muscle recession can be used to treat the residual, nonaccommodative component; however, it may be necessary to base the surgical dosage on the near deviation.

Accommodation, Ocular↗
PubMed2005

Intermittent exotropia, overcorrecting minus lenses, and the Newcastle scoring system.

PURPOSE: We sought to determine whether the Newcastle Control Score (NCS) could be used to indicate a successful outcome in patients with intermittent exotropia that were treated with minus lenses. METHODS: We studied patients with an intermittent exotropia who were prescribed minus lens therapy in an effort to manage their strabismus conservatively. The NCS, which quantitatively estimates the control of an intermittent exotropia, was applied before treatment and 4 months after treatment. The results of minus lens therapy with a pretreatment NCS of > or =5 (group 1) were compared with those with a NCS of < or =4 (group 2). RESULTS: There were 24 patients (13 girls, 11 boys) treated with minus lenses. The mean age of the patients was 6.8 +/- 3.8 years (range, 2-17 years; median, 5). The mean pretreatment distance angle was 28.5 +/- 10 prism diopters (range, 6-45; median, 30) and the mean post-treatment distance angle was 18.3 +/- 8.9 prism diopters (range, 0-35; median, 18) P = 0.001. Using the NCS minus lenses significantly (P = 0.041) improved control of exotropia. In group 2 (n = 16) 75% had improved scores post-treatment compared with 62.5% in group 1 (n = 8), P = 0.68. CONCLUSIONS: These data suggest that the NCS is a useful method to indicate the success in the control of intermittent exotropia with conservative treatment with minus lens therapy.

Accommodation, Ocular↗
PubMed2005

Long-term study of accommodative esotropia.

PURPOSE: This study aimed, using a large sample size, to determine the long-term results of standard treatment of accommodative esotropia and identify predictors of outcome while minimizing bias in data collection and analysis. METHODS: Data from all the files of a large, long-established pediatric ophthalmology practice were collected and analyzed using a masked protocol. The study included every esotropic patient who had been prescribed glasses. Criteria for patient inclusion were designed to conform to earlier studies by the authors. RESULTS: The database totaled 1307 patients, of who 354 met inclusion criteria. A greater difference between near and distance esodeviation (AC/A relationship) correlated with a higher rate of deterioration of accommodative esotropia control (P < 0.0001). Deterioration also positively correlated with earlier age of onset (P < 0.0001), inferior oblique overaction (P = 0.0005), and amblyopia (P < 0.005). CONCLUSIONS: This study demonstrates that a high AC/A relationship increases the likelihood of deterioration of accommodative esotropia, supporting the earlier studies, as well as the accuracy of this database. It also represents a new model for the utilization of clinical trials' bias-reduction principals in the analysis of retrospective data.

Accommodation, Ocular↗
PubMed2006

Long-term refractive and biometric outcomes following diode laser therapy for retinopathy of prematurity.

PURPOSE: To assess the long-term refractive and biometric outcomes of diode laser-treated eyes in threshold retinopathy of prematurity (ROP). METHODS: Cycloplegic autorefraction and biometry (Zeiss IOLMaster) were performed, at a mean follow-up of 11 years, on 16 laser-treated eyes with threshold ROP and 9 comparison eyes with subthreshold untreated ROP. RESULTS: The laser-treated eyes had a mean spherical equivalent of -2.33 D with a mean astigmatic error of 1.38 D. The comparison eyes had a mean spherical equivalent of +1.07 D with a mean astigmatic error of 0.42 D. This trend toward increased myopia in treated eyes did not achieve statistical significance (p=0.08). The myopia in the laser group appeared to be slowly progressive in nature when compared with earlier refractive data for these patients. The laser-treated eyes had reduced anterior chamber depth (ACD) compared with the subthreshold eyes (p=0.02). When physiologic accommodation was inhibited by cycloplegic drops, the anterior chamber deepened by 0.13 mm in the laser-treated eyes and by 0.06 mm in the comparison eyes. This effect of accommodation on ACD did not differ significantly between the two groups (p=0.23). The laser-treated eyes and the comparison eyes did not differ significantly in terms of axial length, corneal power, corneal diameter, or lens power. However, both groups had steeper corneas, shallower anterior chambers, and shorter axial lengths when compared with historical full-term controls. CONCLUSIONS: Myopia in premature infants requiring laser treatment for ROP is associated with a shallowing of the anterior chamber and a steepening of the cornea. Physiological accommodation is not impaired by laser therapy or by severe ROP.

Accommodation, Ocular↗
PubMed2006

Analysis of human crystalline lens accommodation.

The behavior of the human crystalline lens during accommodation is analytically studied. The lens is modeled as a closed axisymmetrical membrane shell of varying thickness enclosing an incompressible liquid. To simulate zonular tension associated with lenticular accommodation, an axisymmetrical radial force or displacement is imposed around the shell equator. Two second-order, simultaneous, nonlinear governing differential equations are derived. Numerical results, obtained from the investigation of human lens profiles of three independently published MRI images and a drawing of a microphotograph, demonstrate that when zonular traction within the physiological force range of the ciliary muscle is exerted, both central lens thickness and central optical power increase. Qualitatively, these increases are independent of lens shape. However, the magnitude of these changes is dependent on the initial profile of the lens and is enhanced by the "natural" variation in capsular thickness. Only when a pulling force significantly exceeds the force capacity of the ciliary muscle does the lens flatten and its central thickness and optical power decrease.

Accommodation, Ocular↗
PubMed2003

Refractive lensectomy and accommodating lens implantation in a case of hyperopia.

We present a 39-year-old woman with high hyperopia who developed an intolerance to contact lenses due to dry-eye syndrome and Grave's disease. Refractive lensectomy with implantation of a custom-made +31.00 diopter (D) accommodating intraocular lens (IOL) (1CU, HumanOptics) was performed in both eyes. This foldable IOL has modified haptics with transmission elements that allow axial movement of the IOL optic and capsular bag secondary to contraction of the ciliary muscle. The calculated pseudophakic accommodation induced by the anterior shift of a +31.00 D IOL is 2.20 D per millimeter of axial displacement. After 6 months, the accommodative range determined by defocusing was 3.00 D. The subjective near point with best distance correction was 32.00 cm. Refractive lensectomy and implantation of an accommodating IOL based on focus shift may be a refractive solution in eyes with high hyperopia and a short axial length.

Accommodation, Ocular↗
PubMed2003

Understanding the accommodating intraocular lens.

PURPOSE: To review current accommodating intraocular lens (IOL) designs and introduce a new design consisting of a plus lens and a minus lens. SETTING: Cornea Consultants of Boston, Boston, Massachusetts, USA. METHODS: Computer simulation studies of a model eye calculated the pseudoaccommodation range with different powers of 1 IOL or of 2 IOLs acting as a doublet. RESULTS: The doublet consisting of a convex (plus) lens and a concave (minus) lens gave a greater range of power change than a single convex lens or a doublet consisting of 2 convex lenses. The greater range of power results from the plus lens moving forward. CONCLUSION: The results show that an IOL design consisting of positive and negative lenses that move closer or farther from each other offers a greater range of pseudoaccommodation than other designs.

Accommodation, Ocular↗
PubMed2004

Secondary procedures after presbyopic lens exchange.

PURPOSE: To assess the indications, incidence, and outcome of secondary procedures after presbyopic lens exchange (PRELEX). SETTING: Private practice, Siena, Italy. METHODS: This prospective nonrandomized single-surgeon study comprised 52 patients having PRELEX by phacoemulsification and multifocal intraocular lens (IOL) implantation. The preoperative mean spherical equivalent (SE) was +2.50 diopters (D) +/- 1.38 (SD) (range 0 to +6.0 D). RESULTS: Monocular PRELEX was performed in 8 patients who canceled the fellow-eye surgery because of halos; in this group, the residual refractive error was corrected by photorefractive keratectomy (PRK) in 4 eyes, but this did not alleviate halos and IOL exchange was ultimately needed in 7 eyes. Binocular PRELEX was completed in 44 patients; in this group, 14 eyes (8 patients) had PRK for a residual error. The postoperative mean absolute SE in the 18 PRK-treated eyes was 0.33 D (95% confidence interval [CI] of improvement, 0.57-1.32) and the mean uncorrected visual acuity, 0.8 (95% CI of improvement, 0.32-0.45). The final SE was within +/-0.5 D in 15 eyes (83.0%) and within +/-1.0 D in 18 eyes. Halos after PRK were unchanged in 6 patients, slightly improved in 4, and improved in 2. Photorefractive keratectomy or IOL exchange was needed in eyes with a preoperative SE between plano and +1.75 D (15/40 eyes, 38%) and not needed in eyes with a preoperative SE greater than +1.75 D (0%) (95% CI of difference, 23%-53%). CONCLUSIONS: Presbyopic lens exchange in eyes with emmetropia and low hyperopia was associated with a significantly higher percentage of secondary procedures. Photorefractive keratectomy enhancement can improve distance vision but has a limited effect on halos.

Accommodation, Ocular↗
PubMed2004

Anterior chamber optical coherence tomography study of human natural accommodation in a 19-year-old albino.

Anterior segment optical coherence tomography is a new method to explore the anterior chamber. The target can be focused and defocused with positive or negative lenses to reproduce the conditions of natural accommodation. We studied accommodation in an albino patient because the absence of pigment allows the infrared beam to penetrate the iris and explore the modifications of the ciliary body and the crystalline lens during natural accommodation in a human subject.

Accommodation, Ocular↗
PubMed2004

Accommodation measurements in a prepresbyopic and presbyopic population.

PURPOSE: To study the efficacy of several subjective and objective methods of accommodation measurement in normal prepresbyopic and presbyopic populations to identify appropriate methods for measuring the outcome of accommodative restorative procedures. SETTING: University of Houston, College of Optometry, Houston, Texas, USA. METHODS: Thirty-one normal subjects with a mean age of 43.7 years (range 31 to 53 years) participated. Accommodation was measured monocularly using 3 subjective approaches--the push-up test, minus lenses to blur, and a focometer--and 2 approaches measured with a Hartinger coincidence refractometer, in which accommodation was stimulated with minus lenses to blur and topical pilocarpine 6%. RESULTS: The push-up method overestimated accommodative amplitude relative to objective measures in 28 subjects. Two subjective methods, minus lenses to blur and the focometer, produced comparable results, but with lower amplitudes in younger subjects and higher amplitudes in older subjects compared with objective methods. Comparable results were obtained when accommodation was stimulated in 1 of 2 ways and measured with the Hartinger. Pilocarpine elicited stronger accommodative responses than distance blur for subjects with low accommodative amplitudes. Pilocarpine 6% produced stronger responses in subjects with light irides than in those with dark irides. CONCLUSIONS: Hartinger-measured accommodation provides more realistic measurement of accommodative amplitude than the subjective methods tested, especially in the presbyopic population. In presbyopic subjects, the subjective tests resulted in accommodative amplitudes up to 4.0 diopters greater than those measured with objective tests. Measurements of accommodative amplitude are best achieved with objective methods to stimulate and measure accommodation.

Accommodation, Ocular↗
PubMed2005

Performance of the 1CU accommodating intraocular lens in relation to capsulorhexis size.

PURPOSE: To assess the correlation between continuous curvilinear capsulorhexis (CCC) size and visual outcomes in patients with an accommodating intraocular lens (IOL). SETTING: Heidelberg IOL and Refractive Surgery Research Group, Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany. METHODS: Nineteen eyes had phacoemulsification and implantation of a 1CU accommodating IOL (HumanOptics AG). Three months after surgery, the uncorrected and best corrected distance and near visual acuities and the distance corrected near visual acuity were measured. Retroillumination photographs were taken to assess CCC size and centration and the amount of overlap between the CCC and IOL optic. The photographs were analyzed using Evaluation of Posterior Capsule Opacification system software. RESULTS: The mean age of the patients was 53.5 years (range 30 to 73 years). The mean uncorrected distance acuity improved from 0.05 preoperatively to 0.70 at 3 months and the best corrected near acuity, from 0.30 to 0.94. The mean postoperative distance corrected near acuity was 0.5 (range 0.1 to 1.0), which improved to 0.9 with near correction. The mean CCC size (4.3 mm) and amount of CCC decentration (0.35 mm) did not correlate with visual outcomes. However, there was a correlation between the amount of CCC-optic overlap (mean 35%; range 16% to 55%) and distance corrected near acuity (r = 0.641, P = .003). Distance corrected near acuity was better with less overlapping; that is, with a larger CCC. CONCLUSIONS: A larger capsulorhexis with less CCC-optic overlapping gave better near visual outcomes. Results indicate that an overlap between 25% and 35%, which correlates with a CCC between 4.5 mm and 5.0 mm, provides the best capsule strength without compromising accommodation with the single-piece 1CU IOL.

Accommodation, Ocular↗
PubMed2004

Quality of vision after AMO Array multifocal intraocular lens implantation.

PURPOSE: To evaluate safety and efficacy of Array SA40N multifocal intraocular lens (IOL) (AMO) implantation in cataract surgery. SETTING: Helsinki University Eye Hospital, Helsinki, Finland. METHODS: In this prospective randomized comparative trial, 80 patients scheduled for cataract surgery were selected based on preoperative counseling and randomized to have multifocal or monofocal IOL implantation. Fifty-three eyes of 35 patients received a multifocal IOL and 67 eyes of 40 patients, a monofocal IOL. The incidence of complications and visual outcome in the multifocal and monofocal IOL groups were compared. Quality of vision was measured by comparing the severity of visual symptoms (glare, halos, and cataract symptoms score), changes in functional impairment measured by a 7-item visual function test (VF-7), changes in global measures of vision (trouble and satisfaction with vision), and range of accommodation and contrast sensitivity. RESULTS: Intraoperative and postoperative complications and adverse events were few and required no further surgical intervention. Both distance and near visual acuities were significantly better in the multifocal group than in the monofocal group; the difference was most prominent in distance corrected near acuity (P<.001). Thirty-five eyes (67.3%) in the multifocal group and 10 eyes (14.9%) in the monofocal group achieved a distance corrected near acuity of J6 (20/40) or better; 30 eyes (56.6%) and 19 eyes (28.4%), respectively, achieved a best corrected distance acuity of 20/20 or better. Glare symptoms decreased postoperatively in both groups but were slightly more common in the multifocal group. In contrast, halos were significantly more common at 1 month in the multifocal group (P<.001). Contrast sensitivity values were slightly lower with multifocal IOLs at almost all spatial frequencies, but the difference was not significant. The change in the quality of life postoperatively, measured with the VF-7, was significant and identical in both groups. CONCLUSIONS: Pseudophakic eyes with multifocal IOLs had better distance and near acuity and range of accommodation than eyes with a monofocal IOL. Slightly lower contrast sensitivity and increased perception of halos by subjects with the multifocal IOL appear to be an acceptable compromise to enhanced near and distance vision.

Accommodation, Ocular↗
PubMed2004

Near vision restoration with refractive lens exchange and pseudoaccommodating and multifocal refractive and diffractive intraocular lenses: comparative clinical study.

PURPOSE: To evaluate near visual performance after implantation of a pseudoaccommodating intraocular lens (IOL) (Crystalens AT-45, eyeonics) or a multifocal IOL (refractive model, AMO Array; diffractive model, AcriTec TwinSet) after lens surgery. SETTINGS: Instituto Oftalmologico de Alicante, Miguel Hernandez University, Alicante, Spain. METHODS: Forty patients were included in this prospective clinical comparative study. The patients were divided into 3 groups according to the type of IOL implanted. Group 1 included 24 eyes (12 patients) implanted with the Crystalens IOL; Group 2, 32 eyes (16 patients) with the Array IOL, and Group 3, 24 eyes (12 patients) with the TwinSet IOL. Bilateral phacoemulsification and IOL implantation were performed in all patients, and the follow-up was 1 year. The postoperative main visual outcome evaluations were uncorrected and best corrected distance and near visual acuities, mean add for near, and best distance-corrected near acuity. RESULTS: In Group 1, the mean uncorrected near acuity was 20/40 preoperatively and 20/25 after 1 year. The mean preoperative best distance-corrected near acuity was 20/32 and 20/25 after 1 year. In Group 2, the mean uncorrected near acuity was 20/40 and 20/25, respectively. The mean preoperative best distance-corrected near acuity was 20/32 and 20/25 after 1 year. In Group 3, the mean uncorrected near acuity was 20/63 preoperatively; after 1 year, it was approximately 20/25. The mean best distance-corrected near acuity was 20/50 and 20/25, respectively. A neodymium:YAG laser capsulotomy was performed for posterior capsule opacification when required, with no change in the refractive outcome. CONCLUSIONS: Implantation of multifocal and pseudoaccommodating IOLs provides adequate near vision restoration. The TwinSet IOL provided faster recovery of near vision than the other 2 IOLs. The Crystalens IOL provided less postoperative visual phenomena with favorable near vision. The Array IOL achieved the most comfortable distance and near vision.

Accommodation, Ocular↗
PubMed2004

Functional vision after cataract removal with multifocal and accommodating intraocular lens implantation: prospective comparative evaluation of Array multifocal and 1CU accommodating lenses.

PURPOSE: To compare the efficacy (functional vision, spectacle dependence) of the Array multifocal intraocular lens (IOL) (Advanced Medical Optics) and the 1CU accommodating IOL (HumanOptics AG). SETTING: Hartswood Hospital, Brentwood, United Kingdom. METHODS: This prospective study comprised patients scheduled to have standard phacoemulsification surgery with IOL implantation. Patients expressing a preference for spectacle independence were allocated to the Array multifocal IOL group. Those expressing no preference received the 1CU accommodating IOL. Efficacy measures included distance and near uncorrected visual acuity (UCVA), dynamic retinoscopy, and patient-reported spectacle independence. RESULTS: Seventeen patients (34 eyes) had bilateral implantation of the Array multifocal IOL, and 5 patients (9 eyes) had implantation of the 1CU accommodating IOL. Six to 18 months after surgery, 82.4% of eyes in the multifocal IOL group and 77.8% in the accommodating IOL group achieved a distance UCVA of 20/20 (Snellen) or better; the difference between groups was not significant. However, a significantly greater proportion in the multifocal IOL group than in the accommodating IOL group (76.5% versus 44.4%) achieved a near UCVA of N5 (Snellen 20/40) or better (P=.0068). Sixteen patients (94.1%) with Array IOLs and 2 patients (50.0%) with 1CU IOLs reported spectacle independence. Dynamic retinoscopy showed that the mean accommodative effect in the 1CU group was 0.44 diopter. CONCLUSIONS: In this single-surgeon single-site study, a greater proportion of Array multifocal IOL recipients than 1CU IOL recipients achieved functional near visual acuity. Only 1 patient with an Array IOL required corrective spectacles at the last visit.

Accommodation, Ocular↗
PubMed2004

Optical formula to predict outcomes after implantation of accommodating intraocular lenses.

PURPOSE: To analyze the effect of optical parameters on the outcomes of accommodating intraocular lens (IOL) implantation in cataract surgery. SETTING: Department of Ophthalmology, KULeuven University, Leuven, Belgium. METHODS: Thin-lens approximation optics were used to obtain a formula containing the following variables: axial length (AL), mean keratometry (Km), anterior chamber depth (ACD), and presumed anterior shift of the IOL (dACD). The influence of these variables was separately analyzed. RESULTS: The accommodative amplitude (AA) decreased with a longer AL and higher Km. The AA varied between -5.4 diopters (D) and 0.0 D in eyes with an AL between 20.0 mm and 28.0 mm and a Km between 38.0 D and 52.00 D. The dACD was also a significant factor influencing the AA. The ACD had less influence on the AA. CONCLUSION: The obtained formula could guide selection of candidates for accommodating IOL implantation.

Accommodation, Ocular↗