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At least 847 records · Page 47Linked to original sources
PubMed1987

Intraocular lens power calculations. A practical evaluation in normal subjects at the Wilmer Institute.

The practical value of preoperative intraocular lens power calculations in "normal" eyes with less than 4.50 diopters (D) of myopia or hyperopia was evaluated in a consecutive series of 520 eyes that underwent cataract extraction and lens implantation by four experienced surgeons at The Wilmer Ophthalmological Institute. The observed postoperative results with the lenses selected by the surgeons were compared with results calculated for the measurement-predicted emmetropic power lens and for a standard 20-D lens. The need for postoperative spectacle correction of residual refractive errors was comparable for all three choices of lens. Only two eyes (0.4%) would have developed greater than 4.00 D of refractive error with either the "implanted" or "predicted-emmetropic" lenses, as would 11 eyes (2.1%) with the "standard" 20-D lens. The surgeons' deviation from the calculated emmetropic lens did not reduce postoperative refractive error.

Aged↗
PubMed1990

Experimental radial thermokeratoplasty in rabbits.

Radial thermokeratoplasty is a new technique designed to reduce hyperopia. We evaluated the histopathological effect at 2, 4, and 30 days following radial thermokeratoplasty in rabbit corneas. Surgical complications included variable-sized coagulations and microperforations in two eyes. Light microscopy disclosed that the burns were 90% in depth and healing occurred by epithelial ingrowth. The stroma surrounding the coagulation was acellular early but keratocyte repopulation was apparent by 30 days. A retrocorneal membrane four to five cells thick was noted at the early time points; however, by 30 days only a double layer of spindle-shaped cells remained. By electron microscopy, damage to surrounding endothelial cells was estimated to be 300 microns (from the center of the coagulation). Our results suggest that radial thermokeratoplasty, which utilizes a temperature of 600 degrees C placed within the cornea to a depth of 90%, will cause significant damage to the corneal endothelium beneath and surrounding the coagulation site.

Animals↗
PubMed1991

Poorly differentiated primary orbital sarcoma (presumed malignant rhabdoid tumor). Radiologic and histopathologic correlation.

A 47-year-old man presented with acquired hyperopia and gaze-evoked visual loss. Computed tomography and magnetic resonance imaging demonstrated a well-circumscribed intraconal tumor. Histopathologic studies indicated that the tumor was a poorly differentiated primary orbital sarcoma compatible with malignant fibrous histiocytoma or malignant rhabdoid tumor. To our knowledge, no case of primary orbital malignant rhabdoid tumor has been previously described in an adult.

Cell Differentiation↗
PubMed1991

Photorefractive keratectomy for astigmatism. Initial clinical results.

Excimer laser photorefractive keratectomy, developed to perform radially symmetric ablations to correct myopic or hyperopic refractive errors, was used to perform toric ablations designed to correct cylindrical errors. An expanding slit was used to flatten the cornea in the steep meridian. Four contact lens-intolerant patients underwent this procedure for correction of astigmatism (two patients after penetrating keratoplasty, one patient after corneal ulcer, and one patient with naturally occurring high astigmatism). In each patient, surgery reduced the regular component of the astigmatism; residual irregular astigmatism limited spectacle-corrected acuity in one patient. All patients experienced a shift in spherical equivalent toward hyperopia. Toric ablations with the excimer laser appear to represent a promising strategy for the correction of compound myopic astigmatism that does not rely on creation of deep corneal incisions, excisions, or compression sutures.

Astigmatism↗
PubMed1997

Intraocular lens power prediction in patients who undergo cataract surgery following previous radial keratotomy.

BACKGROUND: Previous experience has shown that there is no technical difficulty in performing cataract surgery on patients who have previously undergone radial keratotomy. However, some researchers have reported inaccuracy in intraocular lens (IOL) power selection. OBJECTIVES: To assess the visual and refractive outcomes of our patients and to compare different formulas and variables to improve accuracy in power determination. MAIN OUTCOME MEASURES: Ten eyes subjected to phacoemulsification with in-the-bag posterior chamber lens implantation 79 months (range, 36-118 months) after radial keratotomy were evaluated in this study. The IOL power was retrospectively calculated for each eye using the Binkhorst, SRK II, and Holladay formulas with the current keratometry reading, the refractive-derived keratometric value (K), the current refractive-derived K, and the adjusted K. The final refractive result was used as a criterion to judge the accuracy and predictability for each approach. RESULTS: Three eyes underwent an IOL exchange after initial surgery. Among the 7 eyes that did not undergo an IOL exchange, a hyperopic shift that regressed approximately 3 months after surgery occurred in the early postoperative period. At the final examination, 5 of the 7 eyes had a hyperopic error, with 2 eyes showing more than 1.00 diopter (D). Overall, in an average of 27 months (range, 9-80 months) of follow-up, an uncorrected visual acuity of 20/40 or better was obtained in 6 (60%) of the eyes. All 10 eyes had a 20/25 or better postoperative best-corrected visual acuity. The mean (+/-SD) spherical equivalent refraction was changed from -0.78 +/- 3.49 D preoperatively to 0.45 +/- 1.31 D postoperatively. We found that the Binkhorst and Holladay formulas are more accurate than the SRK II formula. With the use of an adjusted K (ie, the current average K minus 1.0 D) in combination with the Binkhorst and Holladay formulas, most of the eyes would achieve a refraction of -2.00 to +0.50 D. CONCLUSIONS: A corneal flattening effect caused by cataract surgery tends to occur in eyes that have undergone previous radial keratotomy. The use of an average between the Binkhorst and Holladay formulas, aiming for -0.75 D with an adjusted K, seems to be a more accurate and predictable method for IOL power calculation. This approach could reduce the chance of postoperative hyperopia.

Aged↗
PubMed1990

Optical causes of experimental myopia.

Experiments in which chicks are reared wearing a translucent goggle, or some similar device designed to degrade the retinal image, usually result in the induction of a significant degree of myopia. The induced myopia is due to enlargement of the vitreous chamber of the eye. Despite extensive change in the size, shape and refractive index distribution of the crystalline lens, its refractive power is static in the embryonic and early chick eye. The contribution to myopia of the cornea is uncertain; some studies have indicated either an increase or a decrease in corneal radius of curvature while others found no change. The fact that experimental myopia can be produced in chicks even when the optic nerve has been cut or when the degraded retinal image is restricted to one sector of the eye suggests that accommodation is not involved. Nevertheless, when the retinal image is degraded by being defocused with convex or concave lenses, myopia (concave lenses) or hyperopia (convex lenses) results. Chicks wearing concave or convex soft contact lenses from the day of hatching develop refractive states equal to the lens power (+8 and -10 diopters) within one week. The ability of the eye to vary its refractive development according to the sign of defocus suggests a role for accommodation. However, study of the ciliary muscle and accommodative apparatus of myopic and emmetropic chick eyes does not reveal any morphological differences that might indicate that the myopic eye had experienced an increased level of accommodation.

Accommodation, Ocular↗
PubMed2002

Teebi hypertelorism syndrome: report of a family with previously unrecognized findings.

We present a family consisting of a mother, a daughter, and a son with Teebi hypertelorism syndrome, including some previously unrecognized manifestations. The clinical findings include a prominent forehead, arched eyebrows, pronounced hypertelorism, long philtrum, mild interdigital webbing, fifth-finger clinodactyly, umbilical anomalies, and hypotonia. The mother and daughter also had ptosis requiring surgical correction. The daughter has bilateral iridochorioretinal colobomas with high hyperopia and a small umbilical hernia. The son has less striking facial features but was born with a small omphalocele, large ASD secundum, PDA, bilateral cryptorchidism right hydronephrosis, and a cystic left kidney. The mother had an umbilical hernia requiring surgical correction as a child and a history of heart murmur. Both children have normal hearing and mild developmental delay. Their high-resolution karyotypes were normal and the FISH for 22q11 microdeletion was negative in the daughter. We conclude that cardiac defects in Teebi hypertelorism syndrome are not rare findings and that eye colobomas and renal anomalies were previously unrecognized.

Abnormalities, Multiple↗
PubMed1991

Robin sequence with facial and digital anomalies in two half-brothers by the same mother.

Two half-brothers by the same mother presented with the Robin sequence and facial and digital anomalies. The mother has a normal face and mild hyperopia without abnormality on radiographs of the hands, feet, and pelvis. The older son is 4 years and the younger is 6 months old. Both have normal psychomotor development. To the best of our knowledge this familial association has not been reported before and probably represents a previously unrecognized heritable malformation syndrome. The occurrence of the syndrome in 2 half-brothers by the same unaffected mother suggests X-linked recessive inheritance.

Child, Preschool↗
PubMed2005

Interstitial deletion of chromosome 12q: genotype-phenotype correlation of two patients utilizing array comparative genomic hybridization.

Interstitial deletions of chromosome 12q are rare, with only 11 reported cases in the literature. We recently described two cases with cytogenetically identical interstitial deletions of the long arm of chromosome 12. Here, we report on a third patient, a 26-month-old male with a cytogenetically-identical interstitial deletion: 46,XY,del(12)(q21.2q22). Phenotypic features of this male proband included craniofacial and ectodermal anomalies, genitourinary anomalies, minor cardiac abnormalities, mild ventriculomegaly on brain MRI, hyperopia, and developmental delay. To further define the extent of the chromosomal aberration, microarray-based comparative genomic hybridization (array CGH) analysis was performed and the array data was compared to one of our previously reported cases. Although cytogenetic analysis of the two patients was concordant, molecular analysis by array CGH revealed that the patients had discordant distal breakpoints. The determination of molecular breakpoints and phenotypic analyses in these two patients, in conjunction with previously reported cases, leads us to propose a 12q deletion phenotype and a possible genetic locus for hyperkeratosis pilaris/ulerythema ophryogenes.

Child, Preschool↗
PubMed2000

Visually induced changes in components of the retinoic acid system in fundal layers of the chick.

Eye growth is visually regulated via messengers that are released from the retina. The retina involves a yet unknown algorithm to analyse the projected image so that the appropriate growth rates for the back of the eye are ensured. One biochemical candidate that could act as a growth controller, is retinoic acid (RA). Previous work (Seko, Shimokawa and Tokoro, 1996; Mertz et al., 1999) has shown that retinal and choroidal RA levels are indeed predictably changed by visual conditions that cause myopia or hyperopia, respectively. We have studied in which fundal tissues aldehyde dehydrogenase-2 (AHD2) and retinaldehyde dehydrogenase-2 (RALDH2), enzymes involved in RA synthesis, are expressed and at which levels the effects of vision on RA levels may be controlled. Using Northern blot analysis, we have found that the retinal mRNA level of the AHD2 is up-regulated after 3 days of treatment with negative lenses (negative lenses place the image behind the retina). The abundance of the retinal mRNA of a RA receptor, RAR-beta, was up-regulated already after 6 hr of treatment with positive lenses (positive lenses place the image in front of the retina). The up-regulation persisted for at least 1 week. Finally, we have studied the effects of an inhibitor of RA synthesis, disulfiram, on the visual control of eye growth. We found inhibition of myopia as induced by frosted goggles ('deprivation myopia') but no significant inhibitory effects on refractive errors induced by +7D or -7D lenses. Our results are in line with the hypothesis that RA may play a role in the visual control of eye growth. The RA system differs from a number of other candidates (dopamine, cholinergic agents, opiates) in that it distinguishes between positive and negative defocus, similar to the immediate early gene ZENK (Stell et al., 1999). The exact time kinetics of the changes have still to be worked out since it is possible that the changes in RA relate to already occurring changes in growth rather than to initial steps of the signaling cascade.

Age Factors↗
PubMed1983

Binocular visual form deprivation in human infants.

Visual acuity was measured with a preferential looking technique in infants and toddlers with binocular form deprivation. Of the 10 children in the study, there were 5 with congenital cataracts and 5 with uncorrected high refractive errors. Infants with cataract surgery before 2 months of age showed normal early development of visual acuity. A 4 to 6 month delay before treatment resulted in reduced acuity but recovery subsequently occurred. Infants with high hyperopia or astigmatism showed no acuity deficits in the first year of life when tested with optical correction. One case of early meridional amblyopia was detected in the third year of life. The deficit was not permanent and, after a period of optical correction, there was recovery of visual acuity to normal levels.

Age Factors↗
PubMed1986

Functional differences between free alternators and non-alternators successfully treated for strabismic amblyopia.

Visual acuity was examined in patients successfully treated for strabismic amblyopia, and with equal refractive error in the two eyes (no more of 4 diopters of hyperopia). Patients able to freely alternate fixation showed equal visual acuity in the two eyes without optical correction. An optical correction in front of the ex-amblyopic eye was needed, in order to achieve equal visual acuity in patients unable to freely alternate fixation. No correction was necessary for the sound eye. This difference is attributed to a residual anomaly of accomodation of the ex-amblyopic eye. It is concluded that the concept of cure of strabismic amblyopia based on the attainment of equal visual acuity needs re-evaluation.

Accommodation, Ocular↗
PubMed1992

Multiple defects in the retinal nerve fiber layer in glaucoma.

We investigated the parameters that correlated with multiple defects in the retinal nerve fiber layer in 77 human eyes with normal-tension glaucoma, 110 with chronic high-tension glaucoma, and 102 control eyes. All 187 glaucomatous eyes had a nerve defect that was multiple in 20 cases. Correlation was significant between the multiple defect and the type of defect in the nerve fiber layer (P less than 0.002), size of the disc (P less than 0.02), and oblique insertion of the disc (P less than 0.02), as evaluated by the chi-square test. By multivariate analysis, refractive error was a high-ranking risk factor for multiple defect. Eyes with multiple defects tended to have moderate myopia, a focal nerve fiber layer defect and a small optic disc (category scores 0.0932, 0.0878 and 0.0697) and were less likely to have a diffuse defect in the nerve fiber layer, emmetropia or hyperopia, and a normal disc size (category scores -0.1077, -0.0705, and -0.548). The multiple defect in the retinal nerve fiber in glaucoma was frequently focal and correlated with myopia and a small optic disc.

Adult↗
PubMed1996

Chick eye optics: zero to fourteen days.

Ocular dimensions and refractive state data for chicks 0 to 14 days of age were obtained from 234 untreated control eyes of birds treated unilaterally in previous work involving various defocussing lenses and/or translucent goggles. Refractive state and corneal curvatures were measured in vivo by retinoscopy and ophthalmometry respectively. Intraocular dimensions were measured by A-scan ultrasonography, after which the eyes were removed, weighed and measured. In some cases (n = 52) intraocular dimensions and lens curvatures were obtained from frozen sections of enucleated eyes. The hyperopia of hatchling chicks (+6.5 +/- 4.0 D) initially decreases rapidly and then more gradually to +2.0 +/- 0.5 D by 16 days. The distribution of refractive errors is very broad at Day 0, but becomes leptokurtotic, with a slight myopic skew, by Day 14. Corneal radius is constant for the first four days, possible as a result of pre-hatching lid pressure, and then increases linearly, as do all lens dimensions, axial diameter and equatorial diameter. Schematic eyes were developed for Days 0, 7, and 14.

Animals↗
PubMed1986

Autosomal dominant juvenile vitreoretinal degeneration and retinal detachment.

To study the inheritance and clinical picture of a new form of vitreoretinal dystrophy I examined 18 family members of a family with six generations. Seven patients, three male and four female, in three consecutive generations were observed to be affected indicating autosomal dominant inheritance. The disease was characterized by juvenile degeneration of the vitreous with detachment of the vitreous body and some floating vitreous opacities, cystoid degeneration of the peripheral retina with whitish glistening stippled areas of superficial retinal degeneration, spotty hyperpigmentation, patches of retinal atrophy with pigmentations, occasional atrophic retinal holes, and in four family members at the age of 4 to 12 years, unilateral or bilateral retinal detachment with breaks in the peripheral retina. Most patients had hyperopia with or without astigmatism. In eyes without detached retina, the disease did not show any marked progression, the lens was clear, the posterior fundus and the retinal and choroidal vessels were normal, and the visual acuity, visual fields, dark adaptation, colour vision, electroretinograms, and visually evoked response findings were normal.

Adult↗
PubMed1978

The angiographic ocular choroidal crescent: distortion with intraorbital and remote intracranial pathology.

The ocular choroidal plexus can be identified on virtually all normal internal or common carotid angiograms. Posterior flattening of the choroid is often seen with retrobulbar tumors. This angiographic appearance can also be observed in some patients with papilledema and increased intracranial pressure. In these patients, ampulliform dilatation of the dura and subarachnoid space just posterior to the globe produces a retrobulbar mass effect that can mimic true retrobulbar tumor. Enlargement of the ocular choroid crescent is an unusual angiographic finding and can be seen with intraocular expansile lesions such as unilateral axial high myopia with posterior staphyloma. An abnormally small, shrunken choroidal blush can be seen with microphthalmia, extreme degrees of hyperopia, and in the phthisical eye.

Carotid Arteries↗
PubMed1997

Optic disc morphology in myopic primary open-angle glaucoma.

OBJECTIVE: To evaluate the morphology of the optic disc in highly myopic eyes with primary open-angle glaucoma. METHODS: Color stereo optic disc photographs of 44 patients with primary open-angle glaucoma and a myopic refractive error exceeding -8 diopters were morphometrically examined and compared with disc photographs of 571 patients with primary open-angle glaucoma and a myopic refractive error of less than -8 diopters. RESULTS: In the highly myopic group, compared to the control group, the optic disc was significantly (P < 0.0001) larger, the disc shape was significantly (P < 0.0005) more elongated, and the optic cup depth was significantly (P < 0.0001) more shallow. The loss of neuroretinal rim was more concentric, and localized retinal nerve fiber layer defects were found significantly less frequently in the highly myopic group than in the control group. In the highly myopic group, zone beta of parapapillary atrophy was significantly (P < 0.0001) larger. CONCLUSION: The optic disc morphology in primary open-angle glaucoma differs significantly between highly myopic eyes and eyes with hyperopia or low to moderate myopia. The highly myopic eyes are characterized by secondary macro-discs with elongated shape, shallow and concentric disc cupping, large parapapillary atrophy, and low frequency of localized retinal nerve fiber layer defects. Glaucomatous optic nerve damage in highly myopic eyes, compared to eyes with a normal refractive error, is more diffuse than localized.

Female↗
PubMed1993

The prevalence of ocular disorders among Hispanic and Caucasian children screened by the UCLA Mobile Eye Clinic.

A cross-sectional study was performed to describe the prevalence of ocular abnormalities among six and seven year old children of Hispanic and Caucasian ancestry in Los Angeles County. Data were obtained from vision screenings of lower to middle income Hispanic and Caucasian children completed by the UCLA Mobile Eye Clinic at public neighborhood elementary schools and community centers between January and August of 1989, and January and March of 1990. Out of a total sample of 854 children, 64% were Hispanic; 36% were Caucasian; 51% were female and 49% were male. Ocular abnormalities observed were similar for both ethnic groups. Caucasians, however, showed non-significant, but consistently higher prevalences of most ocular abnormalities. Stronger associations between ethnicity and visual abnormalities were observed within the female subgroup. For example, hyperopia was found more commonly among female Caucasian children than among female Hispanic children (p < 0.01). This information can be used in planning for the eye care needs of communities with Caucasian and Hispanic components.

Child↗