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Contact lenses for children.

Contact lenses for children are used to correct a variety of conditions. This paper reviews fitting of soft, silicone elastimer, and rigid gas-permeable contact lenses for therapeutic treatment of aphakia, anisometropia, myopia, hyperopia, esotropia, irregular astigmatism, and nystagmus. Cosmetic custom designs are described for the treatment of aniridia, albinism, amblyopia, and corneal disfigurement. Working with children and gaining their trust requires inventiveness and patience. Prescribing contact lenses for them requires developing good cooperation between the child, the parents, and the practitioner. The rewards of contact lenses wear for the appropriate pediatric patients include improving not only their vision but also their quality of life.

Child↗

[The postoperative change of depth of anterior chamber, refraction and anterior capsulorhexis size after intraocular lens implantation].

We evaluated postoperative shrinkage of anterior capsule, depth of anterior chamber, and refraction in 161 eyes, on which we performed continuous curvilinear capsulorhexis and phacoemulsification, and then implanted an intraocular lens in the capsular bag. We measured the depth of anterior chamber, anterior capsulorhexis size, contact surface with intraocular lens, and quantity and rate of anterior capsular shrinkage on the basis of anterior segment photographs before the operation, and 1 week, 1 month, and 3 months after the operation. After operation the depth of the anterior chamber deepened gradually, anterior capsulorhexis size narrowed, and refraction tended to hyperopia. There was a correlation in anterior chamber depth and anterior capsulorhexis size between preoperative and postoperative values but no correlation in refraction. The depth of the anterior chamber was dependent on the degree of anterior capsular shrinkage. There was a correlation between the depth of anterior chamber and the degree of anterior capsular shrinkage.

Aged↗

Prevalence of ocular disorders among 6- and 7-year-olds in Santa Monica, California.

BACKGROUND: Undetected ocular disorders can cause serious problems in a child's mental and social development. METHODS: To investigate relationships between ocular disease, gender and ethnicity in children, vision screening examination data was analyzed from the UCLA Mobile Eye Clinic (MEC), collected from 1985 to 1990 on first graders (69.9 percent 6- and 30.1 percent 7-year-olds) in Santa Monica, California. RESULTS: The sample consisted of 1,469 individuals, of whom 48.1 percent were female and 51.9 percent were male. Ethnicity data was available from 1988 to 1990 on 834 individuals, of whom 46.9 percent were Hispanic, 27.9 percent were White. 11.5 percent were Black, 4.4 percent were Asian, and 9.2 percent were of other races. Significantly more females than males had refractive errors, specifically hyperopia and astigmatism, and uncorrected visual acuity of 20/50 or worse in at least one eye. There were no significant associations of ethnicity or sex with any other disease category. The overall prevalences of other diseases were less than 4 percent. Of the 6- and 7-year-olds studied in Santa Monica, California, 18.5 percent had refractive errors. CONCLUSIONS: Screening for ocular disorders at an early age allows for detection of problems, especially refractive errors, that might affect school performance if uncorrected.

California↗

Nondetectable cone and rod electroretinographic responses in a patient with Cockayne syndrome.

A 10-year-old girl complained or poor vision in both eyes. The patient showed progeria, physical and mental retardation, sensorineural hearing loss, cutaneous photosensitivity, hyperopia, poor pupillary dilation, exotropia, salt-and-pepper fundi, nondetectable cone and rod electroretinographic (ERG) responses, cerebral atrophy on computed tomography, and demyelination of periventricular white matter on magnetic resonance imaging. We believe that nondetectable cone and rod ERG responses in Cockayne syndrome, as demonstrated in our patient, may be uncommon.

Brain↗

Calibration and validity of an eccentric photorefractor.

A new graphical calibration method was developed to convert the photorefractive reflex into refractive error. With this graphical method, the refractive error can be obtained for pupil sizes and for photorefractive reflex sizes which have not been precalibrated. In the conventional method, the refractive error associated with non-precalibrated pupil and reflex sizes is obtained by interpolating between neighbouring precalibrated points. This introduces error because the relationship between refractive error and pupil and reflex size is not linear. Three hundred and sixty-one children aged between 36 and 65 months were clinically examined and photorefracted. The refractive error obtained using retinoscopy and the eccentric photorefractor agreed well with each other, although the photorefractor tended to under-estimate refractive error. Using the referral criteria developed by Chan, O.Y.C. and Edwards, L.M. (Refraction referral criteria for Hong Kong Chinese Children. Ophthal. Physiol. Opt. 14, 259-256, 1994), the photorefractor had a sensitivity of 74.6% and a specificity of 96.4%. All the under-referred cases were borderline, having just failed the referral criteria. All the cases with hyperopia of > + 2.0 D, astigmatism of > 1.25 D and visual acuity of worse than 6/18 were identified.

Calibration↗

Implantation of posterior chamber lenses of more than 30 dptr.

Posterior chamber lenses of more than 30 dptr. are supposed to correct preexisting high hyperopia. With high diopters, however, problems emerge which are not to be found in eyes requiring lower lens powers. These problems are neurosensory disorders, residual accommodation, difficulties in power calculation, unavailability of appropriate lenses and thick lens optics. These difficulties and possible solutions are addressed referring to cases of IOL powers between 46 and 53 dptr.

Aged↗

New progeroid disorder.

We report on a 10-year-old Caucasian male with a prematurely aged appearance, delayed bone maturation and dental development, pronounced acro-osteolysis with brachydactyly, and distinctive cutaneous findings including hard, confluent skin lesions with some clinical and histologic resemblance to those of juvenile hyaline fibromatosis (JHF). He also had hyperopia, sensorineural hearing loss, and elevated TSH. Linear growth and intellectual functions were normal. We believe that this patient represents a new progeroid disorder.

Abnormalities, Multiple↗

[The optical power of the corneal epithelium. In vivo evaluation].

PURPOSE: The refracting power of the corneal epithelium is relatively unknown. We measured the keratometric refracting power of the cornea on 15 eyes of patients undergoing photorefractive keratectomy with and without epithelium. MATERIALS: The readings were performed with a videokeratoscope TMS-1. Three readings were averaged to obtain the mean and standard deviations. RESULTS: By removing the epithelium, there was an increase in corneal refracting power. The mean change was +1.19 D (standard deviation +/- 0.36 D) at 1 mm of the center of the cornea. On all patients the optical power of the cornea increased after epithelium removal. CONCLUSION: The curvature of the Bowman membrane is steeper than the cornea with epithelium. A change in the thickness of the epithelium is related to a modification of the optical power of the cornea. The optical role of the epithelium is to compensate surface irregularities of the Bowman membrane and could explained in part the hyperopia in the first months after excimer laser.

Cornea↗

[Primary epiretinal gliosis (author's transl)].

Analyzing the findings of 45 patients with primary epiretinal gliosis in 51 otherwise entirely healthy eyes, the clinical features of the disease are elaborated. The disorder is characterized by the occurance of a glial membrane covering the retina in the area of the posterior pole and leading to a distorsion of the posterior pole and leading to a distorsion of the subjacent and surrounding tissues. Most frequently, the foveal region is involved, but the foveola is often spared. With increasing distance from the center the frequency of involvement decreases. Only in very rare cases the membrane extends beyond a distance of 5,5 mm from the center of the retina. The density of the membrane varies from case to case. Average visual acuity of the eyes evaluated in this study was 0,45. In no case it was worse than 0,05. The incidence of the disease increased with both increasing myopia and hyperopia. The average age of the patients was 55 years. There was no predominance of either men or women. The glia cells which compose the membrane originate from the innermost layers of the retina, from where they extend on the retinal surface through a defect in the inner limiting membrane. The reason for the formation of the defects is not yet understood. It is also unknown if the presence of such defects is absolutely necessary for the development of this condition.

Adolescent↗

The Glenn A. Fry Award Lecture (1995). Myopia development in childhood.

PURPOSE: The Orinda Longitudinal Study of Myopia is a 12-year project examining predictive factors for the onset of myopia, the underlying etiologies of myopia, and normal eye growth in school children. METHODS: This paper reports on all measurements made of the ocular components (cycloplegic refractive error, corneal curvature, crystalline lens power, and axial ocular dimensions), parental history of myopia, and near work activity in children participating in the Orinda Longitudinal Study of Myopia between 1989 and 1993. An analysis of the interaction between parental history of myopia and children's near work is conducted on the cross-sectional study data from 1993. RESULTS: The cross-sectional and longitudinal data show a gradual decrease in refractive error from low hyperopia toward emmetropia, no shift in corneal curvature, a gradual decrease in crystalline lens power, thinning of the crystalline lens, and elongation of the eye between the ages of 6 and 14 years. Parental history is more contributory to a statistical model predicting myopia than is near work, but near work is a significant factor as well. We can find no evidence of statistical interaction between parental history and near work in explaining the presence or absence of myopia. CONCLUSIONS: The emmetropization process is evident in the gradual decrease in refractive error toward emmetropia, the axial elongation of the eye, and the compensating decrease in crystalline lens power. Both nature and nurture play a role in the etiology of myopia, although the predominant role appears to belong to a positive parental history of myopia. This role does not appear to be through an interaction between parental myopia status and children's near work activity.

Adolescent↗

Photorefractive keratectomy for the treatment of compound myopic astigmatism using the ablatable mask.

Eight eyes of 8 patients with compound myopic astigmatism were treated with excimer laser photorefractive keratectomy (PRK) using a hand-held ablatable mask in conjunction with the Summit excimer laser. The attempted correction ranged from -1.25 to -400 dioptres (D) of astigmatism and 0 to -8.00 D of myopia. All eyes had attained at least 6 months of postoperative follow-up. Five of the 8 eyes achieved an unaided visual acuity of 6/12 or better. Postoperative refractions ranged from -0.50 to -3.50 D of refractive cylinder and from +0.50 to -3.75 D of spherical error. Decentration of the ablation zone was encountered in 3 eyes due to shifts in patients' fixation. Technical difficulty with the use of the hand-held ablatable mask limited the widespread application of this procedure and it has now been superseded by newer excimer laser systems which can correct astigmatism without having to employ a mask. Despite this, because of the theoretical ability of the mask to correct any form of refractive error, the concept of the mask shape transfer process will remain as a potential alternative in refractive surgery, especially for correction of hyperopia and hyperopic astigmatism.

Adult↗

New aspects of contact lenses in ophthalmology.

The introduction of the hydrophilic contact lens has been a significant advance in ophthalmology for the correction of ametropia, as well as for the therapy of corneal disease. The number of potential contact lens candidates has been greatly expanded by the introduction of both spin-cast and lathe-cut lenses composed of a variety of individual hydrophilic polymers. Myopia, hyperopia, presbyopia, aphakia and moderate astigmatism can be corrected with a reasonable degree of success with the present lenses. Even in keratoconus hydrophilic lenses offer a nonsurgical alternative, especially when combined with spectacle overcorrection. The introduction of hydrophilic bandages in the treatment of corneal disease has been an important addition to the therapeutic armamentarium of the ophthalmologist. When properly applied, these lenses can provide subjective relief of pain while serving to protect the damaged cornea from the traumatic action of the lids and desiccating effects of the atmosphere. The hydrophilic material is permeable to many topically instilled medications and tends to prolong the contact time of the drugs with the corneal surface. Proper fitting of the bandage lenses can eliminate superficial corneal irregularities and, thus, improve the visual acuity while treatment progresses. Medical indications for the use of this therapy include bullous keratopathy, dry eye syndromes, chemical burns, exposure keratitis, and neurotropic keratitis. A number of recurrent erosions and ulcerations have also responded to this form of therapy. Surgical indications include lacerations, postoperative lamellar and penetrating keratoplasty, and keratectomies. One of the most promising applications concerns their use in the postoperative management of alkaline burns. Best results have been obtained by constant wear of the bandage lens, with topical administration of steroids, antibiotics, and saline solution (hypotonic or hypertonic) as indicated. The possible deleterious effects of standard ocular medication containing preservatives has been overstated. Patients receiving medications without preservatives must be placed on prophylactic antibiotics to avoid secondary infection. In many cases, the therapeutic efficacy is closely related to the diameter and curvature of the bandage lens as well as the inherent physical properties of the polymers. With meticulous fitting and close observation complications have been minimal. In many instances the results have been dramatic, but even if unsuccessful the method provides a safe and relatively simple nonsurgical alternative in the treatment of severe corneal disease. Just as with older modalities, the ultimate success or failure depends upon the intrinsic nature of the disease process as well as reasonable therapeutic application based on a knowledge of the mechanics involved.

Chemical Phenomena↗

Optic nerve head swelling in the Hadju-Cheney syndrome.

The Hadju-Cheney syndrome is one of the idiopathic acroosteolyses. Associated neurologic abnormalities are often a result of progressive basilar invagination. A 48-year-old man with the Hadju-Cheney syndrome developed progressive bilateral visual loss. On examination, he had hyperopia, choroidal folds, optic nerve head swelling, and mild optic neuropathy. Computed tomographic scans showed massive enlargement of both intraorbital optic nerve sheaths. Improvement occurred after optic nerve sheath fenestration. Visual loss due to optic nerve meningocele can occur in the Hadju-Cheney syndrome. Optic nerve sheath fenestration can result in visual improvement. It is unclear whether the occurrence of optic nerve meningocele is causally or fortuitously related to the Hadju-Cheney syndrome.

Fundus Oculi↗

Excimer laser refractive surgery.

Excimer laser photorefractive keratectomy and excimer laser in situ keratomileusis are relatively new treatment modalities that can be used to correct refractive errors of the eye. They are most commonly used to correct myopia (nearsightedness) but can also be used to correct hyperopia (farsightedness) and astigmatism. The excimer laser alters the refractive state of the eye by removing tissue from the anterior cornea through a process known as photoablative decomposition. This process uses ultraviolet energy from the excimer laser to disrupt chemical bonds in the cornea without causing any thermal damage to surrounding tissue. The modified anterior corneal surface enables light to be focused on the retina, thereby reducing or eliminating the dependence on glasses and contact lenses. We discuss in detail all aspects of excimer laser refractive surgery--techniques, indications and contraindications, clinical outcomes, and complications.

Humans↗

[Scale for evaluating desirable ametropia or eumetropia].

GOAL: The purpose of this study is to assess the degree of desirable ametropia in cataract surgery. MATERIAL AND METHODS: A scale for evaluation was created. It allows to measure the desired distance for a neat uncorrected vision (desired ametropia) after cataract surgery that presbyopic patients (monocular vision) would like to obtain. This scale helps to calculate the power of the intraocular lens to be implanted. The scale was shown to a series of 50 consecutive presbyopic patients. Refraction was the same in both eyes. The interest of patients in the evaluation of their desirable ametropia was measured on a scale from 0 to 5. RESULTS: Interest was good for 50% of patients (grade > or = 3). Mean distance desired by patients for a neat uncorrected vision was 1 meter. Preoperative myopia and hyperopia have no significantive influence upon the distance desired for a neat uncorrected vision. CONCLUSION: The choice of the power of the lens implanted during cataract surgery should take into account the patients' desires. An evaluation of the postoperative desirable ametropia should be systematic.

Activities of Daily Living↗

[Predictability of amblyopia in ametropic children. Apropos of 96 cases].

PURPOSE: The aim of this cross-sectional retrospective study was to analyze the predictability of amblyopia in children with myopic and hyperopic unilateral and bilateral ametropia. MATERIALS AND METHODS: One hundred and sixty two eyes of 96 children, (mean age: 8.6 years), were included in this work. Mean visual acuities and significant refractive errors were estimated for all the cases. The frequency of amblyopia and strabismus was studied in cases without amblyopia and in cases with medium and high grade amblyopia. RESULTS: Mean visual acuities were significantly higher in cases of bilateral myopia (p < 0.001) and hyperopia (p < 0.05) compared with unilateral ametropia. The frequency of myopic eyes (p < 0.01), eyes with high grade of myopia (p < 0.002) and anisomyopic eyes (p < 0.001) was significantly higher in cases of high amblyopia compared with cases without amblyopia. Strabismus (p < 0.05) were also significantly more frequent in cases of high amblyopia as well as in cases of myopic eyes (p < 0.01). Moreover, in the group of high amblyopia, 6 cases (6/7) had developed an intolerance for contact lenses. CONCLUSIONS: The risk of developing high grade amblyopia appeared significantly associated with unilateral medium and high level myopia. Strabismus and difficulties with good correction of anisometropia by contact lenses or spectacle appeared to be predisposing factors. This observation would suggest the indication of refractive surgery might be useful in these particular cases. To conclude, this study emphasizes the importance of early treatment of ametropia to reduce the incidence of amblyopia in children.

Amblyopia↗

Effects of lifetime lead exposure on spatial and temporal visual function in monkeys.

Detailed characterization of several aspects of visual function was performed in two groups of monkeys (Macaca fascicularis) exposed to lead continuously from birth. One group of four monkeys was dosed from birth onward with 500 microg/kg/day of lead as lead acetate, while another group of six monkeys was dosed with 2000 microg/kg/day. Blood lead levels peaked in the former group at 50 microg/dl early in life; the latter group had peak blood lead concentrations averaging 115 microg/dl during infancy. Blood lead concentrations decreased before one year of age to stable levels of 25 or 35 microg/dl in the low and high dose groups respectively. Spatial and temporal visual function was assessed using a psychophysical procedure at 7-9 years of age. Six age-matched controls were tested concurrently. Two treated monkeys had severe hyperopia: one was assessed on temporal vision only and the other was not assessed. Spatial data from a third monkey were considered suspect and excluded. Six of the nine treated monkeys in which temporal vision was assessed had thresholds below control values at low and/or middle frequencies under high luminance conditions. Low-luminance temporal vision was not affected. There was no evidence of impairment of spatial visual function in lead-exposed monkeys with normal refractive status at either high or low luminance. This study suggests that temporal visual function may be preferentially impaired as a result of lifetime exposure to a moderate body burden of lead, although these results require replication before definitive conclusions may be drawn.

Animals↗

[Reasons for return of patients for consultation after prescription for corrective glasses].

PURPOSE: To determine the frequency and causes of patients' complaints when they return visit less than one year after refraction. METHODS: Among all the patients who received a prescription of corrective glasses from January to December 1996, we include in the study those who returned less than one year after the refraction because they were dissatisfied with their spectacles. In order to determine the cause of their complaints, the patients were evaluated ophthalmologically and, depending on the complaints, an oto-rhino-laryngologic, dental, cardiovascular or neuro-psychiatric evaluation was made. RESULTS: During this period, 432 patients underwent refraction and had a prescription of corrective glasses. Of these, only 12 (2.8%) came back to consult. A cause could be found in 11 patients: error by opticians (3 patients), intolerance to bifocals (1 patient) and to cylindric lenses (1 patient), sudden onset of hyperopia associated with diabetes mellitus (1 patient), increase of refraction associated with progressive myopia (2 patients), fronto-maxillary sinusitis (1 patient), arterial hypertension (1 patient) and cataract (1 patient). CONCLUSION: Patients who received corrective glasses and return a short item after the refraction with complaints about their spectacles must be reevaluated ophthalmologically. If any cause can't be found, the evaluation should be extended to oto-rhino-laryngologic, dental, cardiovascular, neuro-psychiatric or other examination depending on complaints.

Eyeglasses↗