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PubMed1999

Cycloplegia in African-American children.

PURPOSE: The selection of a cycloplegic agent depends on the desired outcome, the characteristics of the patient receiving the drug, and the associated risks. The Orinda Longitudinal Study of Myopia (OLSM) has used 1% tropicamide to assess the ocular components and cycloplegic refractions in a large cohort of predominantly Caucasian children. Although tropicamide has provided adequate cycloplegia and mydriasis for the OLSM cohort, conventional clinical wisdom and scientific investigations have suggested that tropicamide might not produce adequate cycloplegia and mydriasis for subjects with darker iris pigmentation. In this study one drop of 1% tropicamide followed by one drop of 1% cyclopentolate was used to determine their effectiveness in producing adequate cycloplegia and mydriasis for cycloplegic refraction and ocular component measurements in a group of African-American children. METHODS: Nineteen children [age range 5.5 to 15.6 years, mean 8.4 years +/- (SD) 2.5 years] were tested at Family HealthCare of Alabama, Eutaw, AL. Their accommodative responses were measured using a Canon R-1 autorefractor prior to and at 30, 45, and 60 min after instillation of one drop of 0.5% proparacaine, 1% tropicamide (Mydriacyl), and 1% cyclopentolate (Cyclogyl) in both eyes. A target of 20/155 letters in a 4x4 grid positioned behind a +6.50 diopter (D) Badal lens provided accommodative stimuli of 1.00 D, 2.00 D, and 4.00 D. RESULTS: All results are presented as mean +/-1 SD. Pupils, measured from video frames, dilated rapidly and maximally at 30 min after instillation of eye drops (7.3+/-0.5 mm) Predilation, the mean accommodative responses were 0.17+/-0.29 D for the 1.00 D stimulus, 1.01+/-0.40 D for the 2.00 D stimulus, and 2.77+/-0.74 for the 4.00 D stimulus. At 30 min after drop instillation, the responses were 0.07+/-0.14 D for the 1.00 D stimulus, 0.36+/-0.35 D for the 2.00 D stimulus, and 0.77+/-0.61 for the 4.00 D stimulus. Results were very similar at 45 and 60 min after drop instillation. CONCLUSIONS: Combining 1% tropicamide and 1% cyclopentolate was very effective in providing both cycloplegia and mydriasis adequate for ocular biometry and cycloplegic refractions 30 min after drop instillation in African-American children.

Accommodation, Ocular↗
PubMed2004

Ocular component measurement using the Zeiss IOLMaster.

PURPOSE: Axial length is traditionally measured using A-scan ultrasound. The IOLMaster is a new instrument that uses partial coherence interferometry to measure axial length. We compared the repeatability of these techniques for both an experienced and an inexperienced observer, the agreement between the two techniques, and the effect of cycloplegia on IOLMaster measurements. METHODS: Five measurements of axial length and three measurements of anterior chamber depth were taken with the IOLMaster in two sessions separated by 1 to 12 days in 20 young adults. The two examiners each took measurements, and the subject was then cyclopleged with 1% tropicamide. The IOLMaster readings were then repeated by both examiners, followed by five ultrasound readings. Repeatability was evaluated by calculating the difference between measurements from the two sessions. The mean and standard deviation of these differences was then used to determine the 95% limits of agreement (LoA) for each technique. In addition, the agreement between the IOLMaster and ultrasound was assessed, along with the effect of cycloplegia on IOLMaster readings. RESULTS: The IOLMaster was more repeatable than ultrasound. For axial length, the 95% LoA were -0.11 to +0.07 mm, -0.06 to +0.05 mm, and -0.25 to +0.35 mm, for noncycloplegic IOLMaster, cycloplegic IOLMaster, and ultrasound, respectively. The two instruments showed modest agreement with each other (mean difference, +0.12 mm; 95% LoA, -0.39 to +0.64 mm; p > 0.0125). Cycloplegia had no significant effect on IOLMaster axial length measurements. The 95% LoA for anterior chamber depth measurement were -0.11 to +0.18 mm, -0.06 to +0.04 mm, and -0.19 to +0.21 mm, for noncycloplegic IOLMaster, cycloplegic IOLMaster, and ultrasound, respectively. The IOLMaster gave significantly longer anterior chamber depths than ultrasound (mean, +0.18 mm; 95% LoA, -0.02 to +0.37 mm; p < 0.0125), and cycloplegia produced significantly deeper anterior chamber depths using the IOLMaster (mean, +0.12 +/- 0.09 mm; 95% LoA, -0.05 to +0.29 mm; t = 6.17; p < 0.001). The experienced observer's measurements were more repeatable than the inexperienced observer's for ultrasound, but not for the IOLMaster. CONCLUSIONS: The superior repeatability of the IOLMaster suggests that it should become the standard for axial length measurement. The 95% limits of agreement for the cycloplegic measurements correspond to a change in refractive error of +/-0.12 D.

Adult↗
PubMed2006

The prevalence of refractive errors among schoolchildren in Dezful, Iran.

AIM: To determine the prevalence of refractive errors among schoolchildren in urban and rural areas of Dezful County, Iran. METHODS: In a cross-sectional study, using random cluster sampling, 5721 Dezful schoolchildren were selected from 39 clusters. The participants in the study totalled 5544; 3673 elementary and middle school students and 1871 high school students. For the former group, cycloplegic refraction and for the latter, non-cycloplegic refraction was tested. In all participants, uncorrected visual acuity and best corrected visual acuity were determined, and those with a visual acuity of 20/40 or worse, underwent a complete ophthalmic examination to determine the cause of visual impairment. A spherical equivalent of -0.5 diopter (D) or worse was defined as myopia, +2.0 D or more was defined as hyperopia, and a cylinder refraction greater than 0.75 D was considered astigmatism. RESULTS: The uncorrected visual acuity was 20/40 or worse in the better eye of 224 schoolchildren (3.8% of participants). This figure (percentage) was 14 (0.03%) based on their best corrected visual acuity and 96 (1.7%) with their presenting vision. According to results of cycloplegic refraction, 3.4% (95% confidence interval (CI), 2.5 to 4.4) of the primary and middle school students were myopic and 16.6% (95% CI, 13.6 to 19.7) were hyperopic. For high school students, these rates were 2.1% (95% CI, 0.7 to 3.5) and 33.0% (95% CI, 24.9 to 41.1), respectively, with non-cycloplegic refraction. In the multivariate logistic regression for primary and middle school students, myopia was correlated with age (p = 0.030), and hyperopia was correlated with age (p<0.001) and area of residence (p = 0.007). In high school students, hyperopia again showed a correlation with their area of residence (p = 0.029). CONCLUSION: The present study reveals the considerable prevalence rates of refractive errors among schoolchildren in Dezful County and the high rate of an unmet need for their correction. Although myopia is not very prevalent, the high rate of hyperopia in the studied population emphasises its need for attention.

Adolescent↗
PubMed2003

Identification of infants with significant refractive error and strabismus in a population screening program using noncycloplegic videorefraction and orthoptic examination.

PURPOSE: The second Cambridge Infant Vision Screening Program examined whether screening for accommodative errors by using videorefraction without cycloplegia could effectively serve as a first stage of screening for refractive errors, measured by standard cycloplegic retinoscopy. The screening also included an orthoptic examination for detection of strabismus. METHODS: All infants born in the Cambridge (UK) Health District, over a 2-year period, were invited for screening. Of those 5142 (76%) with mean age 8.1 +/- 0.8 months (SD) attended and received noncycloplegic videorefraction and an orthoptic examination. All those with a focusing error or orthoptic problem, as well as a randomly selected sample of visually normal control subjects, were invited to follow-up a month later for cycloplegic retinoscopy, repeat noncycloplegic videorefraction and orthoptic examination. RESULTS: Of the 5142 screened, 514 had a focusing error or orthoptic problem (positives). Four hundred thirty-nine of these and 284 visually normal control subjects (negatives) attended follow-up. A refractive or orthoptic condition was confirmed in 59.0% of the positive cases, whereas infants in 96.8% of the negative cases were confirmed normal. Adjusting for the proportions of the population represented by those infants seen at follow-up, sensitivity for the screening procedure was calculated at 0.67 and specificity at 0.96. Detailed results are presented in terms of the different conditions detected at screening (far, near, and anisometropic focus and orthoptic error), distribution of greatest axes at screening, and a comparison of initial videorefraction with repeat videorefraction and cycloplegic retinoscopy. CONCLUSIONS: A noncycloplegic screening procedure, simpler to perform than cycloplegic screening, succeeded in detecting a large proportion of infants with significant ametropia, particularly those with significant hyperopia, which is considered to be a strabismogenic and amblyogenic risk factor.

Accommodation, Ocular↗
PubMed1997

Laser in situ keratomileusis for myopia of -2 to -25 diopters.

PURPOSE: To evaluate excimer laser in situ keratomileusis in the treatment of low, high, and excessively myopic eyes in Taiwan, 77 patients (104 eyes) were treated with Nidek EC-5000 excimer laser and divided into four groups. METHODS: In situ keratomileusis was performed with a Chiron or SCMD microkeratome. The Nidek EC-5000 excimer laser was used, with multiple passes and a multiple zone ablation technique was performed for myopia higher than -10.00 D. RESULTS: In eyes with a preoperative spherical power equal to or less than -7.00 D (29 eyes of 18 patients), the preoperative cycloplegic mean spherical equivalent refraction was -5.44 +/- 1.36 D. The mean postoperative subjective spherical equivalent refraction was 0.25 +/- 0.64 D at 1 month, 0.056 +/- 0.55 D at 3 months, -0.069 +/- 0.415 D at 6 months, and 0.022 +/- 0.496 D at 9 months. The predictability of postoperative 9 month results demonstrated that 86.21% of eyes were within +/-0.50 D, 96.55% were within +/-1.00 D, and 100% were within +/-2.00 D of emmetropia. In eyes with a preoperative spherical power equal to or less than -10.00 D and higher than -7.00 D, 26 eyes of 17 patients had a preoperative cycloplegic mean spherical equivalent refraction of -8.41 +/- 0.84 D. The mean postoperative subjective spherical equivalent refraction was -0.043 +/- 1.15 D at 1 month, -0.12 +/- 0.92 D at 3 months, -0.21 +/- 1.05 D at 6 months, and -0.37 +/- 1.04 D at 9 months. The predictability of postoperative 9 month results demonstrated that 76.92% of eyes were within +/-0.50 D, 80.77% were within +/-1.00 D, and 96.5% were within +/-2.00 D of emmetropia. In eyes with a preoperative spherical power equal to or less than -15.00 D and more than than -10.00 D, 40 eyes of 27 patients had a preoperative cycloplegic mean spherical equivalent refraction of -12.65 +/- 1.51 D. The mean postoperative subjective spherical equivalent refraction was 0.275 +/- 1.72 D at 1 month, -0.30 +/- 1.34 D at 3 months, -0.47 +/- 1.23 D at 6 months, and -0.62 +/- 1.23 D at 9 months. The predictability of postoperative 9 month results demonstrated that 62.5% of eyes were within +/-0.50 D, 75% were within +/-1.00 D, and 87.5% were within +/-2.00 D of emmetropia. For 19 eyes of 15 patients with a preoperative spherical power greater than -15.00 D, the preoperative cycloplegic mean spherical equivalent refraction was -19.53 +/- 2.61 D. The mean postoperative subjective spherical equivalent refraction was -0.40 +/- 1.22 D at 1 month, -0.69 +/- 1.34 D at 3 months, -0.83 +/- 1.40 D at 6 months, and -0.65 +/- 2.99 D at 9 months. The predictability of postoperative 9 month results demonstrated that 31.5% of eyes were within +/-0.50 D, 52.63% were within +/-1.00 D, and 63.16% were within +/-2.00 D. CONCLUSION: LASIK is a safe and effective technique for the treatment of low, high, and excessive myopia.

Adult↗
PubMed1992

The repeatability of measurement of the ocular components.

Studies of the ocular components of refraction typically neglect issues of repeatability of measurement methods or analyze method comparison/repeatability data inappropriately using correlation. The authors have examined the repeatability of refractive error measures (retinoscopy, subjective refraction, and Canon R-1 autorefraction, noncycloplegic and cycloplegic), axial dimension measures (Allergan-Humphrey A-scan ultrasound), and corneoscopy (keratometry and KERA photokeratoscopy), and the agreement between different refractive error and corneal measurement methods on 40 pre-presbyopic normal adults. The authors plotted the difference versus the mean of two different measurement occasions (repeatability), or two different methods (agreement), to determine the bias (mean of the differences relative to zero) and 95% limits of agreement of each technique. The most reliable measure of refractive error was autorefraction with cycloplegia, with 95% limits of agreement of +/- 0.32 diopters. Cycloplegic autorefraction had no statistically significant bias compared to cycloplegic subjective refraction. Cycloplegic retinoscopy was the least reliable refractive error measure, with repeat measures on two separate occasions extending over 95% limits of agreement of +/- 0.95 D. Anterior chamber depth was reliable to +/- 0.29 mm, lens thickness to +/- 0.20 mm, and vitreous chamber depth to +/- 0.37 mm. Corneal curvature measures show keratometry to be more reliable (to +/- 0.87 D) than photokeratoscopy (+/- 2.02 D) with a statistically significant bias (paired t-test, P less than 0.0001) of 0.57 D flatter for photokeratoscopy.

Adult↗
PubMed2004

A randomized trial of the effects of rigid contact lenses on myopia progression.

OBJECTIVE: To compare the effects of rigid gas-permeable contact lenses (RGPs) and soft contact lenses (SCLs) on myopia progression in children. METHODS: We randomly assigned 116 subjects to wear RGPs or SCLs. Subjects underwent cycloplegic autorefraction, keratometry, and A-scan ultrasonographic axial length measurements at each annual visit. All analyses were conducted according to the original randomization assignment. The primary outcome measure was the 3-year change in spherical equivalent cycloplegic autorefraction. RESULTS: The mean +/- SD spherical equivalent cycloplegic refractive error progressed -1.56 +/- 0.95 diopters (D) for RGP wearers and -2.19 +/- 0.89 D for the SCL wearers during the 3 years of the study (analysis of covariance [ANCOVA], P<.001). The axial growth of the eyes was not significantly different between treatment groups (ANCOVA, P = .57). The steep corneal meridian of the RGP wearers steepened 0.62 +/- 0.60 D, and that of the SCL wearers steepened 0.88 +/- 0.57 D during the 3 years (ANCOVA, P = .01). CONCLUSIONS: The RGP wearers' myopia progressed less than that of the SCL wearers. The corneal curvature of the SCL wearers steepened more than that of the RGP wearers, but the axial growth was not significantly different between the groups. Most refractive error treatment effect was limited to the first year of the trial. The results of the study provide information for eye care practitioners to share with their patients, but they do not indicate that RGPs should be prescribed primarily for myopia control.

Child↗
PubMed2005

Repeatability of autorefraction and axial length measurements after laser in situ keratomileusis.

PURPOSE: To assess the repeatability and agreement of refractive error measurements and the repeatability of axial length (AL) measurements in patients after laser in situ keratomileusis (LASIK). SETTING: The Ohio State University College of Optometry, Columbus, Ohio, USA. METHODS: Subjective refraction, autorefraction measurements with the Grand Seiko and Humphrey autorefractors, and AL measurements with the IOLMaster were completed for 40 previously myopic LASIK patients under noncycloplegic and cycloplegic conditions on 2 separate occasions. RESULTS: The mean difference between visits for axial length measurements was 0.008 mm +/- 0.04 (SD). The between visits repeatability for all refractive error measurements were <0.75 diopter (D). The mean difference between the subjective refraction and the Humphrey autorefractor for spherical equivalent was statistically significant under noncycloplegic conditions (-0.90 D, P<.0001) and cycloplegic conditions (-2.05 D, P<.0001). The mean difference between subjective refraction and Grand Seiko autorefraction measurements was not significant under noncycloplegic conditions (+0.05 D, 95% limits of agreement [LoA]=-0.99, 1.09; P=.52) conditions but was statistically significant, but not clinically relevant, under cycloplegic conditions (+0.17 D, 95% LoA=-0.73, 1.07; P=.03). CONCLUSIONS: Refractive error measurements after LASIK using the Grand Seiko autorefractor are reliable and agree well with subjective refraction measurements.

Adult↗
PubMed1998

Lasso procedure to revise overcorrection with radial keratotomy.

PURPOSE: To report three patients who underwent the lasso procedure to revise overcorrection with radial keratotomy. METHODS: Case report and review of the literature. RESULTS: Four eyes of three patients who had undergone radial keratotomy with resultant hyperopic overcorrection underwent a lasso procedure. Before the procedure, average cycloplegic refraction spherical equivalent was +3.656 +/- 1.352 diopters, and average manifest refraction spherical equivalent was +2.250 +/- 0.621 diopters. A 10.0 monofilament nylon suture was placed in a circumferencial manner through the corneal stroma and overlapping the old radial keratotomy incisions. At 1 month postoperatively, best-corrected visual acuity was 20/20 in all four eyes, with average cycloplegic refraction spherical equivalent +0.438 +/- 1.423 diopters and average manifest refraction spherical equivalent -0.156 +/- 1.147 diopters. Mean delta cycloplegic refraction spherical equivalent was 3.219 +/- 1.724. CONCLUSIONS: The lasso procedure provides an immediate solution for symptomatic overcorrected hyperopic eyes after radial keratotomy. Predictability and long-term stability necessitate further follow-up.

Adult↗
PubMed1995

Reproducibility of topographic measurements of the macula with a scanning laser ophthalmoscope.

BACKGROUND: The Heidelberg retina tomograph, a scanning laser ophthalmoscope that uses confocal optics to provide high resolution of images, is able to scan the retina in three dimensions to obtain quantitative topographic measurements. The authors evaluated its usefulness for measuring macular lesions by determining the reproducibility of its topographic measurements at the macula. METHODS: For each of ten healthy patients, the authors took five images with the patient's right eye undilated and five with the eye cyclopleged and dilated. As a measure of reproducibility, the standard deviation of height measurements for the same location at the macula was calculated for each patient and then the pooled standard deviation for all patients was calculated. The authors performed similar calculations for the mean depth within a contour line. RESULTS: The pooled standard deviation for height measurements was 47.4 microns in undilated eyes and 36.0 microns in cyclopleged, dilated eyes. The authors obtained an extremely low standard deviation of 2.2 microns when the software calculated relative differences between measurements, such as the mean depth within a contour line. When the average of three height measurement values on 1 day was compared with the average of the three values on another day, the 95% confidence interval was +/- 58.7 microns for mean height values and +/- 3.7 microns for mean depth values within a contour line. CONCLUSIONS: The authors obtained good reproducibility for height measurements with the Heidelberg retina tomograph and excellent reproducibility when the instrument calculated relative differences in height measurements. The authors recommend that patients, especially young patients, be dilated and cyclopleged to obtain lower variability of measurements. The scanning laser ophthalmoscope could potentially be used to quantify small changes in retinal lesions.

Adult↗
PubMed2006

[Comparative study of cyclopentolate drops versus spray in cycloplegia in children].

INTRODUCTION: Instillation of cyclopentolate drops with their irritant effect is difficult for children to bear. The purpose of this study was to compare the tolerance and efficacy of cyclopentolate spray versus drops. MATERIAL AND METHODS: The cycloplegic effect of cyclopentolate spray prepared and conditioned in the hospital was compared with drops in 62 eyes of 32 children consulting in our department. The nonparametric Wilcoxon test for paired data was used to assume there was no significant difference between the refractive measurements with spray or drops. RESULTS: The mean age of our patients was 6.3 years (SD, 3.4 years). The refractive values ranged from -17.3 diopters to +8 spheric diopters and -4 to 0 cylindric diopters. The nonparametric Wilcoxon test for paired data showed no significant difference between cycloplegic measurements with drops or spray. CONCLUSION: Cyclopentolate spray is a good alternative to traditional drops, leading to equal cycloplegic efficacy but greater tolerance in children and easier administration by the nursing staff.

Adolescent↗
PubMed2001

The Correction of Myopia Evaluation Trial (COMET): design and general baseline characteristics.

The Correction of Myopia Evaluation Trial (COMET) is a multicenter, randomized, double-masked, controlled clinical trial evaluating whether there is a difference in the progression of myopia between children wearing progressive addition lenses (PALs) versus conventional single vision lenses (SVLs), as measured by cycloplegic autorefraction. Axial length, measured by A-scan ultrasonography, is an additional outcome measure. To meet the recruitment goal of 450 participants, eligible children ages 6-11 years (inclusive) with myopia in both eyes (spherical equivalent between -1.25 diopters (D) and -4.50 D, astigmatism < or = 1.50 D, and anisometropia < 1.00 D) were recruited at four clinical centers between September 1997 and September 1998. Children who participated were assigned to receive PALs (Varilux Comfort with a +2.00 D addition) or SVLs. Measures include standardized cycloplegic autorefraction (Nidek ARK700A autorefractor), axial length (Sonomed A2500 ultrasound), subjective refraction (Marco TRS system), visual acuity (modified Early Treatment Diabetic Retinopathy Study protocol), accommodation (Canon R-1), and phoria (cover test and Maddox rod). Outcome measures are collected annually; adherence is assessed and prescriptions updated semiannually. Participants are being followed for at least 3 years. COMET enrolled 469 children. Their mean age is 9.3 years (range 6-11 years); 52% are female. COMET children are ethnically diverse, according to a self-report with 46% White, 26% African American, 14% Hispanic, and 8% Asian. Best-corrected visual acuity is better than 20/32 in both eyes. Baseline mean (+/-SD) cycloplegic refractive correction is -2.38 D (+/-0.81) in the right eye and -2.40 D (+/-0.82) in the left eye; mean (+/-SD) axial length is 24.1 mm (+/-0.7) in both eyes. Follow-up of these children will provide a first step in answering the important question of whether there are effective means to slow myopia progression. Study results should be applicable to a large proportion of children with myopia. The study will also provide useful information on myopia progression in children wearing conventional single vision lenses.

Child↗
PubMed2003

Laser-assisted subepithelial keratectomy and photorefractive keratectomy for the correction of hyperopia. Results of a 2-year follow-up.

PURPOSE: To evaluate and compare the efficacy, safety, predictability, and stability of laser-assisted subepithelial keratectomy (LASEK) and photorefractive keratectomy (PRK) for low to moderate hyperopia with a 2-year follow-up. SETTING: Department of Ophthalmology, Masaryk University Hospital, Brno, Czech Republic. METHODS: This prospective comparative single-surgeon study included 216 eyes of 108 patients with hyperopia who received PRK in 1 eye and LASEK in the contralateral eye. The mean patient age was 38.3 years (range 25 to 58 years). The mean preoperative spherical equivalent (SE) cycloplegic refraction was +3.67 diopters (D) +/- 1.15 (SD) (range +2.00 to +5.00 D), and astigmatism was less than 1.00 D. In each patient, PRK was performed in 1 eye (Group A) and LASEK was performed in the other eye (Group B) using the Nidek EC-5000 excimer laser. Postoperative uncorrected visual acuity (UCVA), best corrected visual acuity, contrast sensitivity, manifest and cycloplegic refractions, refractive stability and predictability, postoperative pain, and corneal haze were examined and statistically analyzed. A P value less than 0.05 was considered significant. RESULTS: At 1 week, the UCVA was 20/40 or better in 58% of PRK eyes and 85% of LASEK eyes (P =.037); at 2 years, it was 20/40 or better in 81% and 91%, respectively (P =.076). At 2 years, the UCVA for near was N8 or better in 73% of PRK eyes and 89% of LASEK eyes (P =.064). No patient lost 2 or more lines of Snellen visual acuity. The safety index was 1.03 in PRK eyes and 1.08 in LASEK eyes. Refractive stability was achieved at 6 months in LASEK eyes and at 12 months in PRK eyes. The mean SE cycloplegic refraction decreased from +3.58 D (PRK eyes) and +3.76 D (LASEK eyes) at baseline to +0.74 D and +0.32 D, respectively, at 2 years; in 57% and 78% of eyes, respectively, the refraction was within +/-0.50 D of the targeted refraction. Peripheral corneal haze scores at 3 to 9 months and pain scores at 1 to 3 days were significantly lower in the LASEK group than in the PRK group. CONCLUSIONS: Laser-assisted subepithelial keratectomy for hyperopia up to +5.00 D provided good visual and refractive results. It significantly reduced postoperative pain, grade of peripheral ring-shaped corneal haze, and regression of hyperopia. Hyperopic LASEK provided quicker visual recovery and achieved better efficacy, predictability, and refractive stability than hyperopic PRK.

Adult↗
PubMedDate not supplied

Clear lens extraction to correct high myopia.

PURPOSE: To assess the refractive outcome and postoperative complications in a single surgeon series of clear lens extraction for high myopia. SETTING: Ophthalmology Department, Cornea and Refractive Surgery Unit, Vall d'Hebrón Hospital, Autónoma University of Barcelona, Spain. METHODS: Forty-six clear lens extraction procedures performed in 37 patients from November 1992 to January 1994 by one surgeon were retrospectively analyzed. Capsule tear and vitreous loss, endothelial cell loss, preoperative and postoperative best corrected visual acuity and cycloplegic refraction, and retinal detachment occurrence were looked at. RESULTS: Capsule tear with vitreous loss occurred in one eye (2.17%). Mean endothelial cell loss was 2.6% during the first postoperative year. Best corrected visual acuity was 6/12 or better in 69.4% of eyes preoperatively and in 88.5% postoperatively. Mean cycloplegic refraction was -16.05 diopters (D) preoperatively; the residual cycloplegic refraction was within 1.00 D in 48.4% of eyes and within 2.00 D in 92.5% postoperatively. CONCLUSION: Because of its high predictability, stability, and low morbidity, we believe clear lens extraction is a reasonable refractive surgery option for middle-aged patients with myopia.

Adult↗
PubMed1998

Ocular status of boys with fragile X syndrome: a prospective study.

PURPOSE: The purpose of this study was to determine whether the high rates of ocular problems described in previous retrospective reports of individuals with fragile X syndrome were present in a prospective sample of young boys. Fragile X syndrome is currently considered the leading hereditary cause of mental retardation, with prevalence estimates of 1:2500 to 1:5000 males. METHODS: Forty-eight boys with fragile X syndrome between the ages of 2.5 and 11 years were evaluated for ocular abnormalities. They received complete ophthalmic evaluations including assessment of visual acuity, cycloplegic refraction, ocular motility assessment, and dilated fundus examination. RESULTS: Approximately 25% of the children had clinically significant ocular findings that included refractive errors (17%, primarily hyperopia and astigmatism) and strabismus (8%). Of the 42 children with quantifiable visual acuities, only 1 child, with diagnoses of nystagmus and hyperopia, had a Snellen visual acuity that was not within normal limits for his age. Three of the 5 children with gross measures of visual acuity had clinically significant findings: 2 had hyperopia greater than 3.5 diopters and 1 had esotropia. The other 2 children with gross measures of acuity and the 1 child without visual acuity assessment had cycloplegic refractions of +1.25 to +1.5 and ocular motility appeared normal. CONCLUSIONS: These results suggest that previous reports of high rates of vision problems, particularly strabismus, in boys with fragile X syndrome may have resulted from selection bias. Although we did observe a higher prevalence of strabismus than that found in the general population (8% vs 0.5% to 1%), the proportion of children having strabismus in our sample was much smaller than that reported in other studies of children with fragile X syndrome (30% to 40%). However, 17% of the sample did have significant refractive errors. In addition to evaluating the ocular motility of children with fragile X syndrome, cycloplegic refraction should also be performed to determine whether refractive problems are present.

Child↗
PubMed1999

Photoscreening for refractive errors in children and young adults with severe learning disabilities using the MTI photoscreener.

PURPOSE: To test the potential ability of the MTI photoscreener to facilitate screening for significant refractive errors in children and young adults with severe learning disabilities. METHODS: Thirty-eight patients with severe learning disabilities from a special school were examined with the photoscreener, and underwent cycloplegic refraction, an ophthalmological and an orthoptic examination. The age at examination, the cause of learning disability, the pupil size, the number of photographs required for accurate interpretation, the co-operation of the subject and the presence or absence of strabismus were recorded. An educational psychologist had performed a psychological assessment on all the children. The results of the cycloplegic retinoscopy were compared with the photorefraction results. RESULTS: A photorefraction was possible in 37 patients and cycloplegic refraction in all the patients. The patients had severe learning difficulties with an intelligence quotient of less than 50. All the patients had behavioural problems, 9 patients had associated cerebral palsy, 8 had chronic epilepsy, 1 patient was brain damaged from a non-accidental injury and 1 from a road traffic accident. The mean age of the patients was 10.0 +/- 4.9 years (range 3-18 years), the average pupil diameter during photoscreening was 6.1 +/- 0.9 mm (range 4-8 mm) and the average number of photographs required for each subject was 2.1 +/- 0.9 (range 1-4). The photoscreener detected 10 patients with a manifest strabismus. There was one false positive and one false negative result giving a sensitivity of 92.8% and a specificity of 90%. CONCLUSION: The examination of children with severe learning disabilities for refractive errors can be extremely difficult. The MTI photoscreener is an effective means of screening such children and young adults for refractive errors and strabismus so that the children with these abnormalities may be targeted for a more detailed evaluation.

Adolescent↗
PubMed2004

The age- and gender-specific prevalences of refractive errors in Tehran: the Tehran Eye Study.

PURPOSE: To determine the age- and gender-specific prevalences of refractive errors in Tehran through a population-based study. METHODS: A total of 6497 citizens representing a cross-section of the population of Tehran were sampled from 160 clusters using a stratified, random, cluster sampling strategy. Eligible people were enumerated through a door-to-door household survey in the selected clusters and were invited to participate. All participants were transferred to a clinic for an extensive eye examination and interview. Refractive error was determined using manifest and cycloplegic refraction. Myopia was defined as the spherical equivalent of -0.5 diopters (D) or more and hyperopia was defined as the spherical equivalent of more than +0.5 D. RESULTS: Of those sampled, 4565 (70.3%) people participated in the study. Refraction data for 4354 participants aged five years and over are presented. The age- and gender-standardized prevalence of myopia based on manifest refraction was 21.8% (95% confidence interval [CI], 20.1 to 23.5) and that for hyperopia was 26.0% (95% CI, 24.5 to 27.6). The prevalences based on cycloplegic refraction were 17.2% (95% CI, 15.6 to 18.8) and 56.6% (95% CI, 54.7 to 58.6), respectively. Prevalences of myopia and hyperopia differed significantly among the age and gender groups (P < 0.001). Astigmatism of 0.75 cylinder diopter or greater was present in 29.6% (95% CI, 28.0 to 31.3) of right eyes with manifest refraction and in 30.3% (95% CI, 28.5 to 32.1) with cycloplegic refraction. Among the study population, 6.1% (95% CI, 5.3 to 6.8%) had anisometropia of 1 D or more. CONCLUSIONS: This report has provided details of the refractive status in the population. We have documented prevalences of myopia, hyperopia, astigmatism and anisometropia by age and gender, identifying more affected age- and gender-groups for prevention programs in the community.

Adolescent↗
PubMed2005

Post-cycloplegia myopic shift in an older population.

PURPOSE: To demonstrate that use of a mydriatic agent remains a significant confounder in autorefraction of the presbyopic population. METHODS: The pre- and post-cycloplegic autorefraction results of 37 subjects over 50 years of age were measured using a Humphrey-598 autorefractor. The results of both eyes were included in a multivariate regression analysis. RESULTS: The average age of the patient sample was 63.4 years. The mean spherical equivalent (SEQ) shifts for the hyperopic, myopic, pseudophakic, and emmetropic eyes were -0.53 D (95% CI -0.77 D to -0.39 D; p < 0.001), -0.38 D (95%CI -0.81 D to +0.04 D; p = 0.077), -0.49 D (95% CI -0.78 D to -0.20 D; p = 0.001), and -0.35 D (95% CI -0.59 D to -0.11 D; p = 0.004), respectively. CONCLUSION: Cyclopleged autorefraction in the presbyopic population is associated with a myopic shift that can potentially lead to overestimation of myopic prevalence. This is an important factor in comparing population studies where cyclogleged autorefraction is used in contrast to non-cyclopleged autorefraction and subjective refraction.

Accommodation, Ocular↗