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PubMed1976

Accommodative esotropia during the first year of life.

Two infants developed accommodative esotropia during their first six months of life. One infant, whose age at onset was 4 1/2 months, had 4.50 diopters of hyperopia. The second infant, whose age at onset was 5 months, had 3.50 diopters of hyperopia. In both infants, the eyes completely aligned with hyperopic correction. Two points are stressed. First, when the amount of hyperopia exceeds +3.00, consideration should be given to an accommodative element as the cause of the esotropia, even if the child is only 4 to 6 months old. Second, even with small angles of esotropia, an accommodative element should be considered, if there is a substantial amount of hyperopia.

Accommodation, Ocular↗
PubMed1981

Cycloplegic refraction in esotropic children. Cyclopentolate versus atropine.

Retinoscopy was performed on a population of predominantly white esotropic children younger than 5.5 years with cyclopentolate 1% and atropine 1.0%. Atropine 1.0% revealed +0.34 diopters more hyperopia than cyclopentolate 1.0%, when the mean differences between the two drugs were examined. Mean difference analysis would probably indicate that atropine retinoscopy was unnecessary. However, 22% of the children had +1.0 diopters or more of hyperopia uncovered by atropine. This significant subpopulation suggests that in young patients with esotropia, an atropine refraction is essential to uncover the maximum amount of hyperopia. Almost all of this subgroup with +1.00 or greater hyperopia had an initial cyclopentolate retinoscopy of +2.00 diopters or more. Therefore, retinoscopy using atropine cycloplegia becomes even more important in this population. There was a trend for the greater differences to be in children older than age 2 years. However, these values were not statistically significant.

Accommodation, Ocular↗
PubMed2002

Factors that influence outcomes of hyperopic laser in situ keratomileusis.

PURPOSE: To analyze the influence of preoperative corneal curvature, postoperative keratometric power, and the amount of correction on the outcomes of hyperopic laser in situ keratomileusis (LASIK). SETTING: Clínica Baviera, Instituto Oftalmológico Europeo, Madrid, Spain. METHODS: In this retrospective study, the records of 376 eyes that had LASIK for hyperopia using the Moria LSK-One microkeratome and the Technolas-Keracor 217C excimer laser were reviewed. The results were analyzed by preoperative hyperopia (5 subgroups) and by preoperative (more than and less than 43.0 diopters [D]) and postoperative (more than and less than 48.0 D) mean keratometry. RESULTS: A statistically significant keratometry regression was found in the +3.00 to +3.90 D range (P <.01), a significant decrease in predictability in the +4.00 to +4.90 D range (P <.05), and a significant worsening in safety in the highest range (+6.00 to +7.90 D; P <.05). Comparative analysis of the > or = +4.00 D and <+4.00 D groups showed statistically significant differences in most measurement parameters. The preoperative keratometry did not influence postoperative results with the exception of poorer predictability in the group of preoperative flat corneas in which a high degree of hyperopia was corrected; ie, spherical equivalents within +/-0.50 D were found in 40.4% and 61.0% of cases with flat and steep corneas, respectively (P <.05). The efficacy and safety in eyes that achieved a postoperative keratometry >48.00 D did not differ significantly from the efficacy and safety in eyes that had a lower final keratometric power. CONCLUSIONS: The factor that negatively influenced the outcome of hyperopic LASIK was the degree of hyperopia corrected. Preoperative keratometry did not significantly influence the postoperative results, and postoperative keratometry >48 D did not result in significant worsening of visual results when the attempted correction was less than +4.00 D.

Adult↗
PubMed2003

Analysis of intraocular lens power calculation in post-radial keratotomy eyes.

PURPOSE: To determine whether refractive complications can be prevented by applying the currently most accurate method of intraocular lens (IOL) power calculation in the post-radial keratotomy (RK) patient. SETTING: Department of Ophthalmology, University of California, Davis, Sacramento, and American Eye Institute, Cedars Sinai Medical Center, Los Angeles, California, USA. METHODS: Twenty-four eyes having cataract surgery after RK were studied retrospectively for the final postcataract refraction and for the target refraction used in selecting the IOL. Nine of the eyes were further studied for the keratometry (K) values obtained with different methods and for the theoretical postoperative refraction with an IOL aiming for plano or -1.50 diopters (D) based on the known flatter calculated K, axial length, power of the implanted IOL, and refraction after cataract surgery. RESULTS: Implantation of an IOL aiming for plano in the 24 post-RK eyes would have resulted in a hyperopic refraction in 83.4% cases. The choice of an IOL targeted at myopia reduced the frequency of hyperopia to 42.0% (24 cases). Selection of an IOL calculated with a flatter calculated K and aiming for plano decreased the frequency of hyperopia to 44.4%; however, aiming for -1.50 D still resulted in hyperopia in 44.4% of eyes (9 cases). CONCLUSIONS: Unintentional hyperopia can be significantly decreased but not eliminated as a complication of post-RK cataract surgery. The accuracy of the IOL power determination can be improved if myopia is targeted as the postcataract surgery refractive error and the flatter calculated K is used in the IOL determination.

Humans↗
PubMed2003

Anterior chamber depth in relation to refractive status measured with the Orbscan II Topography System.

PURPOSE: To evaluate the anterior chamber depth (ACD) according to refractive status, assess the reliability of repeated ACD measurements using the Orbscan II Topography System (Bausch and Lomb), compare Orbscan II and IOLMaster (Carl Zeiss Meditec AG) ACD measurements, and investigate the correlation between refraction, axial length (AL), and ACD. SETTING: Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany. METHODS: In this clinical study, 60 patients with a mean age of 43.8 years +/- 18.74 (SD) were assigned to 1 of 3 groups of 20 patients each according to refraction: emmetropia group; hyperopia group (mean +4.84 +/- 1.60 diopters [D]); myopia group (mean -9.64 +/- 3.79 D). Using the Orbscan II system, 3 consecutive ACD measurements (apex and 3.0 mm zone) were performed. The IOLMaster was used to measure ACD and AL. RESULTS: The mean ACD (from epithelium) with the Orbscan II and IOLMaster, respectively, was 3.61 +/- 0.24 mm and 3.61 +/- 0.24 mm in the emmetropia group, 3.03 +/- 0.21 mm and 3.06 +/- 0.24 mm in the hyperopia group, and 3.72 +/- 0.26 mm and 3.73 +/- 0.23 mm in the myopia group. The standard deviation of the repeated Orbscan II measurements increased from 13 to 15 microm from the apex to the 3.0 mm zone. The difference between the apex and 3.0 mm zone of the cornea in all groups ranged from 0.1 to 0.12 mm. The mean AL was 23.52 +/- 0.82 mm in the emmetropia group, 22.14 +/- 0.64 mm in the hyperopia group, and 27.44 +/- 1.67 mm in the myopia group. There was a significant correlation between the spherical equivalent and AL (r = 0.94). CONCLUSIONS: Significantly lower ACD values were found in the hyperopia group than in the other 2 groups. There was no difference in ACD between the emmetropia and myopia groups even though the AL in the myopia group was 4.0 mm longer. No statistical difference in ACD measurements was found between the Orbscan II and IOLMaster.

Adult↗
PubMed2003

Is it possible to differentiate early-onset accommodative esotropia from early-onset essential esotropia?

PURPOSE: To determine the frequency of > or =2.50 diopter (D) hyperopia in infantile esotropia with onset up to the age of 6 months and by evaluating the treatment results of these cases retrospectively, to find the factors that may help to differentiate early-onset accommodative esotropia from early-onset essential esotropia. METHODS: The charts of 256 patients with infantile esotropia were reviewed. Thirtyseven cases, with hyperopia of > or =2.50 D, no other systemic and neurologic disease, and at least 1 year of follow-up, were included in this study. The age at the start of therapy, refractive error, deviation angle, type of therapy (antiaccommodative therapy, surgery) and the presence of amblyopia, latent nystagmus, inferior oblique overaction, dissociated vertical deviation and cross-fixation were recorded for each case. RESULTS: The prevalence of high hyperopia was found to be 14.4% (37/256) in infantile esotropia. In 18 of the cases (48.6%), antiaccommodative therapy alone was found to be adequate (Group I). In the remaining 19, although antiaccommodative therapy was found to decrease the deviation angle significantly (P<0.001), surgery was also required (Group II). Groups were compared with respect to age at the initial examination, refractive error, deviation angle, presence of amblyopia, anisometropia, and inferior oblique overaction, but no factor could be determined to predict the pure refractive ones (P>0.05). Essential infantile esotropia-associated findings did not help because they are rarely evident at the time of initial diagnosis. CONCLUSIONS: Half of the high hyperopic infantile esotropes could be corrected fully by antiaccommodative therapy alone, while the remaining ones could also benefit significantly. It is strongly recommended to try spectacles at first in the treatment of infantile esotropia with hyperopia > or =2.5 D.

Accommodation, Ocular↗
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↗
PubMed2000

Refractive changes in diabetic patients during intensive glycaemic control.

AIMS: To evaluate the clinical course and the characteristics of transient refractive error occurring during intensive glycaemic control of severe hyperglycaemia. METHODS: 28 eyes of patients with persistent diabetes were included in this prospective study. During the observation period, patients underwent general ophthalmological examination and A-mode scan ultrasonography was performed at each examination-at days 1, 3, and 7, and then once every week or every other week until recovery of hyperopia. RESULTS: A transient hyperopic change occurred in all patients receiving improved control after hyperglycaemia. Hyperopic change developed a mean of 3.4 (SD 2. 0) days after the onset of treatment, and reached a peak at 10.3 (6. 1) days, where the maximum hyperopic change in an eye was 1.47 (0. 87) D (range 0.50-3.75 D). Recovery of the previous refraction occurred between 14 and 84 days after the initial assessment. There was a positive correlation between the magnitude of the maximum hyperopic change and (1) the plasma glucose concentration on admission (p<0.01), (2) the HbA(1c) level on admission (p<0.005), (3) the daily rate of plasma glucose reduction over the first 7 days of treatment (p<0.001), (4) the number of days required for hyperopia to reach its peak (p<0.001), and (5) the number of days required for the development and resolution of hyperopic changes (p<0.0001). There was a negative correlation between the maximum hyperopic change of an eye and baseline value of refraction (p<0.01). During transient hyperopia, no significant changes were observed in the radius of the anterior corneal curvature, axial length, lens thickness, or depth of anterior chamber. CONCLUSIONS: The degree of transient hyperopia associated with rapid correction of hyperglycaemia is highly dependent on the rate of reduction of the plasma glucose level. A reduction of refractive index in intraocular tissues, especially in lens, appears to be responsible for this hyperopic change.

Adult↗
PubMed2005

Nine-year refractive changes in the Barbados Eye Studies.

PURPOSE: To describe 9-year changes in refractive errors and estimate incidence of myopia and hyperopia in adults of African-descent, along with associated risk factors. METHODS: The 9-year follow-up of the Barbados Eye Studies (1997-2003) reexamined 2793 surviving cohort members (81% participation). Refractive errors were determined by automated refraction. Myopia/hyperopia were defined as spherical equivalent < -0.5 diopters (D)/> +0.5 D, and the cutoff for moderate-high myopia/hyperopia was 3.0 D. Incidence rates of myopia/hyperopia were estimated by the product-limit approach, based on eyes without such conditions at baseline. Risk factors were evaluated by logistic regression in discrete time hazard models. RESULTS: Nine-year refraction changes varied by age. Persons aged 40 to 49 years experienced hyperopic shifts (median, +0.38 D), whereas persons > or =60 years had myopic shifts (median, -0.75D). Overall 9-year incidence was 12.0% for myopia and 29.5% for hyperopia; rates were 3.6% and 2.0% for moderate-high myopia and hyperopia, respectively. Myopia risk increased with age, baseline nuclear lens opacities (risk ratio [RR] = 1.7; 95% confidence interval [CI]: 1.01-2.9), glaucoma (RR = 6.0, 95% CI: 3.9-9.3), and ocular hypertension (RR = 2.0, 95% CI: 1.3-3.0), while cortical lens opacities decreased risk (RR = 0.6, 95% CI: 0.4-0.9). Incidence of moderate-high myopia was also related to baseline age, nuclear opacities, glaucoma, male gender (RR = 1.7, 95% CI: 1.0-2.8), and diabetes history (RR = 1.9, 95% CI: 1.01-3.5). Hyperopia risk decreased with older age, male gender, and glaucoma diagnosis. CONCLUSIONS: Refractive errors continue to develop frequently in older adults. Nuclear lens opacities, glaucoma, and diabetes increase the risk of older-onset myopia, a result of public health relevance to this and similar African-origin populations.

Adult↗
PubMed2005

[Prevalence of refractive errors in students in Northeastern Brazil].

PURPOSE: To determine the prevalence of refractive errors in the public and private school system in the city of Natal, Northeastern Brazil. METHODS: Refractometry was performed on both eyes of 1,024 randomly selected students, enrolled in the 2001 school year and the data were evaluated by the SPSS Data Editor 10.0. Ametropia was divided into: 1- from 0.1 to 0.99 diopter (D); 2- 1.0 to 2.99 D; 3- 3.00 to 5.99 D and 4- 6D or greater. Astigmatism was regrouped in: I- with-the-rule (axis from 0 to 30 and 150 to 180 degrees), II- against-the-rule (axis between 60 and 120 degrees) and III- oblique (axis between > 30 and < 60 and >120 and <150 degrees). The age groups were categorized as follows, in: 1- 5 to 10 years, 2- 11 to 15 years, 3- 16 to 20 years, 4- over 21 years. RESULTS: Among refractive errors, hyperopia was the most common with 71%, followed by astigmatism (34%) and myopia (13.3%). Of the students with myopia and hyperopia, 48.5% and 34.1% had astigmatism, respectively. With respect to diopters, 58.1% of myopic students were in group 1, and 39% distributed between groups 2 and 3. Hyperopia were mostly found in group 1 (61.7%) as well as astigmatism (70.6%). The association of the astigmatism axes of both eyes showed 92.5% with axis with-the-rule in both eyes, while the percentage for those with axis against-the-rule was 82.1% and even lower for the oblique axis (50%). CONCLUSION: The results found differed from those of most international studies, mainly from the Orient, which pointed to myopia as the most common refractive error, and corroborates the national ones, with the majority being hyperopia.

Adolescent↗
PubMedDate not supplied

Pilocarpine in the management of overcorrection after radial keratotomy.

BACKGROUND: Induced hyperopia is a potential complication of radial keratotomy with few effective treatments. We report the results of a retrospective study to evaluate the effectiveness of pilocarpine in the treatment of eyes overcorrected by radial keratotomy. METHODS: Sixteen eyes of 14 patients, from a consecutive pool of 200 eyes who underwent radial keratotomy, had hyperopia. The patients were subsequently treated with topical pilocarpine. The patients were treated from 3 to 14 weeks (mean, 8.2 weeks). RESULTS: The mean time of diagnosis of hyperopia was 3 weeks after the surgery (range, 1 to 12 weeks). The mean spherical equivalent of the manifest (fogging) refraction was +1.92 diopters (D) (range, +0.75 D to +5.00 D) and the keratometric power ranged from 31.25 D to 41.00 D (mean, 36.05 D). Mean uncorrected visual acuity before the treatment with pilocarpine was 20/50. After the treatment with pilocarpine, the mean spherical equivalent refraction was -0.31 D (range, -1.75 D to +0.50 D). The mean keratometric power was 38.32 D (range, 34.87 D to 43.12 D), with a mean uncorrected visual acuity at 20/25. The patients were followed for 8 to 49 weeks after treatment without pilocarpine (mean, 21 weeks). The mean spherical equivalent refraction and keratometric readings after that period were -0.71 D (range, -2.25 D to +0.25 D) and 38.33 D (range, 36.12 D to 43.12 D), respectively. All eyes in this study had more than 1.00 D of reduction of hyperopia at the conclusion of the study. CONCLUSION: Pilocarpine effectively reduced overcorrections after radial keratotomy. After termination of treatment, the steepening of corneal curvature was maintained.

Adult↗
PubMed2006

Hyperopic LASIK with Esiris/Schwind technology.

PURPOSE: To investigate the refractive and visual outcomes of hyperopic LASIK using Esiris/Schwind technology. METHODS: This retrospective non-comparative observational study included 106 eyes (65 patients) operated with the Esiris/Schwind laser for hyperopia. Eyes were divided into two groups: group 1, < or = +3.99 diopters (D) and group 2, > or = +4.0 D (up to +7.0 D). Visual outcome for distance and near uncorrected (UCVA) and best spectacle-corrected visual acuities (BSCVA) (decimal values), cycloplegic refraction, keratometry (K), pachymetry, and complications were evaluated. RESULTS: In group 1, mean UCVA was 0.4 +/- 0.1 preoperatively and 0.8 +/- 0.2 6 months postoperatively. Mean BSCVA was 0.9 +/- 0.1 preoperatively and 0.9 +/- 0.1 6 months postoperatively. Safety index was 1.1 and efficacy index was 0.97. Mean spherical equivalent refraction was +2.33 +/- 0.9 D preoperatively and +0.3 +/- 0.3 D 6 months postoperatively. Mean K reading was 43.7 +/- 1.1 D preoperatively and 45.0 +/- 1.6 D 6 months postoperatively. In group 2, mean UCVA was 0.3 +/- 0.1 preoperatively and 0.8 +/- 0.2 6 months postoperatively. Mean BSCVA was 0.9 +/- 0.1 preoperatively and 0.9 +/- 0.1 6 months postoperatively. Safety index was 0.98 and efficacy index was 0.92. Mean spherical equivalent refraction was +5.1 +/- 0.9 D preoperatively and +0.4 +/- 0.5 D 6 months postoperatively. Mean K reading was 43.1 +/- 1.6 D preoperatively and 46.0 +/- 1.4 D 6 months postoperatively. Forty-six (90.2%) of 51 eyes in group 1 and 47 (85.5%) of 55 eyes in group 2 were within +/- 0.5 D of emmetropia. At 6-month follow-up, 40 (78%) of 51 eyes in group 1 had UCVA of 20/20 compared to 41 (75%) of 51 eyes in group 2. One (2%) of 51 eyes in group 1 and 4 (7.3%) of 55 eyes in group 2 lost < or = 2 lines of BSCVA. No eye lost >2 lines of BSCVA. CONCLUSIONS: Hyperopic LASIK with Esiris/Schwind technology is effective and safe in the correction of hyperopia up to + 7.0 D. Although a slight statistical significance was found for low hyperopia, visual and refractive results obtained in high hyperopia were encouraging.

Adult↗
PubMed2000

Stimulus deprivation myopia in human congenital ptosis: a preliminary report of 50 unilateral cases.

OBJECTIVE: To investigate the frequency of hyperopia and suspected stimulus deprivation myopia in human congenital ptosis. METHODS: Ametropia was evaluated in both eyes of 50 patients with congenital ptosis. The age at investigation was one year and older, average 6 years and 10 months. The amount of refraction was documented as the spherical equivalent (100% cycloplegia). Differences between the paired eyes of 1.0 dpt or more were defined as anisometropia. Statistical analysis was performed using the chi-square and sign tests. RESULTS: The frequency of myopia was lower (7/50: 14%) than that of hyperopia (43/50: 86%) in the ptotic eye (p<0.001). However, myopia occurred more often in the ptotic eye (7/50: 14%) than in the fellow eye (3/50: 6%, p>0.3). Myopic anisometropia was found only in the ptotic eye (5/50 vs. 0/50, p = 0.06), but was not more frequent than hyperopic anisometropia: (5/50 vs. 9/50, p>0.4). A covered center of the pupil in 27 out of 50 eyes was not associated significantly with myopia (2 of 27 versus 5 of 23, p>0.2). Altogether, we found a significantly higher rate of myopia <-1 dpt and hyperopia > 2 dpt: 10% vs. 1.4% and 40% vs. 10.2% (p<0.001) in comparison with normal school children. CONCLUSION: In summary, the following three findings were noted, of which the first two were expected and the third was not. 1. Compared with the normal population, there was an overall higher frequency of myopia in unilateral congenital ptosis. 2. There was a higher frequency of myopia in the ptotic than in the fellow eye. 3. Compared with the normal population, there was also a higher frequency of hyperopia. The clinical presentation of human congenital ptosis may be influenced by compensating head posture, strabismus, accommodation and biochemical effects, and the condition may therefore differ from the classical well-defined animal model of stimulus deprivation myopia.

Adolescent↗
PubMed2000

Unusual presentations of accommodative esotropia.

PURPOSE: Most patients with accommodative esotropia are first examined between the ages of 6 months and 2 years. This paper discusses unusual presentations of accommodative esotropia that occur outside of this age-group and/or have a precipitating event that triggered the esotropia. In a series of patients who were from 5 to 11 years of age, trauma was the precipitating event. In some of the patients under 6 months of age, high myopia, as well as a moderate to large amount of hyperopia, was the cause. In 1 teenager, diabetic ketoacidosis precipitated accommodative esotropia. METHODS: We reviewed all of our records for the past 25 years involving patients with a diagnosis of esotropia, and we found 17 patients who had unusual presentations of accommodative esotropia. Of 8 who were under the age of 6 months, 2 had high myopia and 6 had moderate to large amounts of hyperopia. Nine patients were older than age 5. Eight of the 9 had suffered trauma associated with the presentation of accommodative esotropia, and 1 patient's accommodative esotropia was associated with diabetes. The patients with myopia received their full myopic correction. The children under 6 months of age with hyperopia received their full cycloplegic refraction, and the children over age 5 received the most plus that they were able to accept in a noncycloplegic state consistent with good visual acuity (at least 20/30 in each eye). RESULTS: In 17 patients, accommodative esotropia was initially controlled with glasses. In a few of the trauma cases, bifocals were required for control of near deviation. Only 2 of the patients, in whom onset was under 6 months of age, came to surgery. One had hyperopia controlled for 2 years with glasses, and the other had myopia controlled for 3 years with glasses. CONCLUSIONS: Accommodative esotropia can occur prior to 6 months of age. It can also occur in older children (5 to 14 years of age) and can be precipitated by trauma or diabetic ketoacidosis.

Accommodation, Ocular↗
PubMed2001

[Treatment of intermediate hypermetropia using laser in situ keratomileusis--retrospective study (1995-1999)].

In this study, the authors present their findings concerning the usage of the LASIK method in 225 cases of hyperopia. This method has been used in our ELAS refractive centre from 1995 in the treatment of hyperopia up to +7.0 D. The average preoperative spherical equivalent in this group was +4.91 D, and in cycloplegic refraction 20 D (+/- 1.94 D). The postoperative average spherical equivalent was 0.53 D (+/- 0.58 D). Uncorrected visual acuity is used as the main criterion in assessing the effectiveness of the refractive procedure. The average uncorrected visual acuity was improved from a preoperative value of 0.4 (+/- 0.27) to a postoperative one of 0.8 (+/- 0.24). The average value of the best correct visual acuity worsened from 0.98 (+/- 0.31) preoperatively to 0.88 (+/- 0.23) postoperatively. This was perhaps caused by the side-effects of laser ablation (glare), which occurred in using LASIK with cases of hyperopia of over 0 D. For this reason, the choice of the LASIK method for correction of middle hyperopia should be made with caution.

Astigmatism↗
PubMed2001

Refractive errors and incident cataracts: the Beaver Dam Eye Study.

PURPOSE: To describe the relation between refractive errors and incident age-related cataracts in a predominantly white US population. METHODS: All persons aged 43 to 84 years of age in Beaver Dam, Wisconsin, were invited for a baseline examination from 1988 through 1990 and a follow-up examination 5 years later from 1993 through 1995. At both examinations, participants had refraction and photographic assessment of cataract, according to a standardized protocol. Myopia was defined as a spherical equivalent of -1.0 diopters (D) or less, hyperopia as +1.0 D or more. The relations between refractive errors at baseline and cataract at baseline (prevalent cataract), 5-year incident cataract, and incident cataract surgery were analyzed by using generalized estimating equations. RESULTS: When age and gender were controlled for, myopia was related to prevalent nuclear cataract (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.23-2.27), but not to cortical and posterior subcapsular cataracts. Myopia was not related to 5-year incident nuclear, cortical, and posterior subcapsular cataracts, but was related to incident cataract surgery (OR 1.89; CI 1.18-3.04). Hyperopia was related to incident nuclear (OR 1.56; CI 1.25-1.95) and possibly cortical (OR 1.25; CI 0.96-1.63) cataracts, but not to posterior subcapsular cataract or cataract surgery. After further adjustment for diabetes, smoking, and education, the association between myopia and incident cataract surgery was attenuated (OR 1.60; CI 0.96-2.64), but the associations between hyperopia and incident nuclear and cortical cataracts were unchanged. CONCLUSIONS: These data support the cross-sectional association between myopia and nuclear cataract seen in other population-based studies, but provide no evidence of a relationship between myopia and 5-year incident cataract. Hyperopia may be related weakly to incident nuclear and cortical cataract.

Adult↗
PubMed2002

Quantification of chick lens alphaA- and delta-crystallins in experimentally induced ametropia.

PURPOSE: The role of the lens in experimentally induced ametropia is not known. A recent study of the chick lens demonstrated optical quality deterioration with the induction of refractive errors, without alteration in lens morphology, size or shape. A change in lens gradient of refractive index (which is dependent on alpha-, beta-, and delta-crystallin concentration and arrangement), could underlie this observation. The purpose of this work was to quantify the concentrations of alphaA- and delta-crystallin in lenses from chick eyes with induced high myopia or hyperopia. METHODS: White Leghorn chicks were unilaterally fitted on the day of hatching either with translucent plastic goggles to induce form-deprivation myopia (n=21) or with +15 D defocus goggles to induce hyperopia (n=14). The ungoggled contralateral eyes were used as controls. The chicks were refracted twice, once on the day of hatching and again seven days later, using streak retinoscopy. On day 7 chicks were sacrificed, lenses decapsulated, and soluble proteins were isolated. Western blot assays were optimized and used to assess crystallin concentration. RESULTS: Analysis revealed no significant difference in alphaA- or delta-crystallin concentration in lenses from eyes induced with form-deprivation myopia and hyperopia as compared to their respective control eyes. Analysis of the difference in medians of delta-crystallin between the control and treated groups of the myopia and hyperopia experiments revealed significance (p=0.030). CONCLUSIONS: This study suggests that with the induction of ametropia, the increased lens spherical aberration previously noted is not due to a change in the absolute concentration of lens alphaA- or delta-crystallin. However, results suggest that the myopic and hyperopic treatments had different effects on lens delta-crystallin concentration. Further investigation is necessary to expand the current knowledge of the role played by the lens in experimental ametropia.

Animals↗
PubMed1999

Laser in situ keratomileus using the LaserSight 200 laser: results of 950 consecutive cases.

PURPOSE: To examine the refractive outcome in 950 consecutive eyes having laser in situ keratomileusis (LASIK) by 1 surgeon with experience in keratomileusis. SETTING: Outpatient excimer laser surgical facility. METHODS: This study comprised 950 consecutive eyes of 475 patients having LASIK as a primary procedure with a LaserSight 200 excimer laser (8.51 software). A nasal hinged flap and a Chiron microkeratome were used. Preoperative cycloplegic refraction was done only in patients younger than 25 years and in all hyperopic cases. Subjective preoperative and postoperative manifest refractions were done after autorefractometry in all cases. In cases of hyperopia, the software was modified by adding 30% to the refractive error. Enhancement results are not included. RESULTS: Of the 950 eyes, 893 (94.00%) were myopic and 57 (6.00%), hyperopic. In the low myopia group (1.00 to 3.99 D) of 223 eyes (24.97%), mean spherical equivalents (SEs) were -2.90 D +/- 0.56 (SD) preoperatively, -0.46 +/- 0.6 D 3 months postoperatively, and -0.41 +/- 0.5 D 6 months postoperatively. In the moderate myopia group (4.00 to 5.99 D) of 205 eyes (22.96%), respective mean SEs were -4.90 +/- 0.7 D, -0.90 D +/- 0.9 D, and -0.67 +/- 0.7 D. In the high myopia group (6.00 to 9.99) of 266 eyes (25.30%), the respective means were -7.70 +/- 1.3 D, -0.76 +/- 0.99 D, and -0.60 +/- 0.8 D. In the extreme myopia group (10.21 to 30.00) of 199 eyes (22.28%), the respective means were -13.30 +/- 2.9 D, -1.30 +/- 1.4 D, and -1.13 +/- 1.3 D. For the entire myopic group, the mean astigmatism was +1.55 +/- 1.38 D, +1.09 +/- 0.92 D, and +0.87 +/- 0.77 D, respectively. The low hyperopia group (1.00 to 2.99 D) of 39 eyes (68.42%) had a mean preoperative SE of +1.80 +/- 0.59 D and mean postoperative SEs of +1.00 +/- 0.76 D at 3 months and +1.16 +/- 0.52 D at 6 months. The respective means in the moderate hyperopia group (3.00 to 6.00) of 18 eyes (31.57%) were +4.62 +/- 1.19 D, +3.71 +/- 1.12 D, and +4.00 +/- 1.07 D. CONCLUSIONS: Laser in situ keratomileus for myopia using the LaserSight 200 excimer laser was stable with time and safe for the correction of different degrees of myopia. In the hyperopic group, marked regression occurred in a large percentage of patients. Thus, we will not perform LASIK for hyperopia until the software improves.

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