SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
In the nordic countries 2 to 4% of the population squint and 3 to 5% develop amblyopia. Identification of these children can be done through a general visual screening at a proper age or by selective screening of high risk groups. Several risk factors can be identified: heredity, failure to emmetropize and high hyperopia at the age of 1 year.
BACKGROUND: A tamponade of the vitreous space with silicone oil will obligatory lead to cataract after 6 to 12 months. Today it is easily possible, to implant an artificial lense in silicone oil filled eyes. However the combination of an artificial lense and silicone oil will lead to a strong inflammation in the anterior segment of the eye. PATIENTS AND METHODS: 22 pseudophacic patients with silicone oil tamponade were examined 2 to 6 months after the operation. In 12 patients simple artificial lenses were implanted, in 10 patients heparin modified lenses were implanted. In 10 cases the lens was implanted followed by the insufflation of silicone oil in the vitreous cavity, in 2 cases a lens was implanted in a silicone oil filled eye and the silicon oil was not removed. In 8 cases the implantation of the artificial lens has been performed some months to years before the insufflation of the silicone oil. The indication for the silicon oil tamponade was a PVR retinal detachment in all cases. The following parameters were examined: Reaction of the pupil to light, pupil round or oval in miosis, examination of the fundus peripherie possible after mydriasis, fixation of the iris with parts of the capsula or with the anterior surface of the lens? In addition in 12 cases the postoperative refraction was compared with the results of the biometry, which was performed before the operation. RESULTS: In the cases with a simple lens in about 50% an incomplete miosis or an oval pupil because of fixation of the iris with parts of the capsula or with the anterior surface of the lense could be observed. In the cases with heparin modified lenses these complications could be observed in 20%. In all cases a strong opacification of the capsula was seen. In 8 of 12 cases with combined procedure a small hyperopia was measured, in 4 cases a large deviation was measured. CONCLUSIONS: The implantation of an artificial lens in silicone oil filled eyes is an alternative to the aphacic status with an Ando Iridectomy. Obviously heparin modified lenses have advantages in these cases. Because of the strong cataract formation we suggest to remove the anterior and the posterior capsula in the first operative session and to implant the haptics of the lens into the sulcus. Because of the high rate of complications generally first a stable retina condition should be reached before the implanation of an artificial lens is performed.
BACKGROUND: Cornea plana is an extremely rare, congenital hereditary malformation of the corneo-scleral shape. The curvatures of cornea and sclera are nearly equal with an indistinct limbus. In addition to the flatness, there is a peripheral sclerocornea that produces a pseudomicrocornea. The low corneal refraction and the short anterior segment often result in hyperopia. Myopia is also described. Usually the posterior segment is not involved. MATERIALS AND METHODS: A young man of 22 years, his three- and five-year-old sons, and his newborn daughter showed this hereditary abnormality of the cornea. In this uncommon anomaly we measured corneal curvature, refraction, diameter and in three of the four patients echographical length of the bulbi. RESULTS: The family showed an autosomal dominant inheritance of the cornea plana. The corneal refraction was less than 32 diopters. The scleral encroachment caused an oval cornea measuring horizontally between 5 and 6.5 mm, vertically 4 to 5 mm. Additionally a pseudoblepharoptosis and a conjunctival xerosis of the father and his sons was observed, which is not regularly found. A-scan measuring of the bulbi revealed age-related normal values. CONCLUSIONS: There is no evidence for progression of this anomaly during life. No therapeutical consequences are necessary. To preserve a satisfactory function a conscientious orthoptical maintainance should be guaranteed.
PATIENT: A polycyclic lesion slightly prominent and yellowish in colour with a mulberry-like surface was incidentally detected in the left eye of a 69-year-old white female. It was located in the nasal horizontal sector of the fundus in a distance of about 5.5 mm from the optic disk. It was surrounded by a bright halo. Retinal arterioles penetrated the lesion superficially and more deeply. The vitreous body was unremarkable. Visual acuity was 0.8 to 1.0 p with a hyperopia of 3.5 dpt. Intraocular pressure was 116 mm Hg. In both eyes partially confluent drusen of the retinal pigment epithelium were present without a serous detachment of the retina. Ultrasound examination revealed an ovally shaped, 1.3-mm prominent solid tumor consisting of highly reflective granular internal echoes with acoustic shadowing behind. X-ray of the skull showed punctate calcifications in the medial orbit. The brain was unremarkable (incl. MRI). In fluorescein angiography the whole tumor was diffusely stained without signs of leakage or subretinal neovascularization. On red-free wide-angle photographs of the retinal nerve fiber layer no localized defects were detected. Neurological and dermatological examination were unremarkable without any hints for tuberous sclerosis or neurofibromatosis. All these findings led to the diagnosis of a solitary retinal astrocytoma. With no therapy performed, the functional and morphological status of the eye remained unchanged one year later. CONCLUSION: A retinal astrocytoma is a hamartoma that usually shows no tendency to grow and there is no need for treatment. It can rarely be the reason of a serous retinal detachment or vitreous hemorrhage. Especially solitary astrocytomas have sometimes been reported to show a tendency towards severe intraocular damage. Additional calcifications showing acoustic shadowing in ultrasound examination are important for the differential diagnosis of retinoblastoma.
The evaluation of 404 consecutively implanted posterior-chamber intraocular lenses after extra-capsular cataract extraction revealed a mean post-operative refractive error of + 0.52 diopters with a standard deviation of +/- 1.27 diopters. Four calculations attracted attention because of their unusually high refractive error of + 3.4 diopters. A post-operative refractive balance excluded measurement or calculation errors. On the other hand, repeated axial length measurements on these four eyes showed a very high mean variation of 3.27 mm. This high variation can be correlated to such typical elevation changes of the central fundus as a tilted disc or posterior staphyloma. High axial length measurements which do not correspond to appropriate amounts of axial myopia should be handled carefully to avoid high amounts of hyperopia following intraocular implantation.
In a six-year-old girl with Rubinstein-Taybi syndrome the ophthalmological findings were as follows: bushy brows, hypertelorism, epicanthus, an antimongoloid slant to the eyelids and hyperopia with an alternating convergent squint. In the sixth year of life juvenile glaucoma with deep cupping of the disk was found.
PURPOSE: To ascertain an examination interval that will not increase the risk of untimely detection of decompensation of accommodative esotropia whether or not initial nonoperative treatment must be supplemented. METHODS: The records of 63 patients with accommodative esotropia examined at 3- to 6-month intervals were reviewed for the occurrence of decompensation, changes in refraction, and the need for increased correction of hyperopia or the addition of bifocals. RESULTS: Decompensation, which was not associated with substantial refractive changes toward or away from emmetropia, occurred in 11 patients. No instance of decompensation occurred in the first 12 months of observation. Although 7 of these decompensated patients were among the 18 (28.6%) requiring supplemental nonoperative treatment, their mean annual refractive change did not differ significantly from the 11 patients who did not decompensate. Eight (18.6%) of 43 patients first controlled earlier than age 48 months later decompensated; 3 (15.0%) of 20 patients with later onset reached this outcome. CONCLUSIONS: The monitoring of controlled accommodative esotropia at intervals of 9 to 12 months is adequate for most patients, at least over the first 2 years, with the exception of those requiring treatment for associated conditions such as amblyopia. Refractive error changes and the need for supplemental treatment after initial control are not prominently associated with decompensation. Age of onset of accommodative esotropia earlier or later than 48 months did not influence rapidity of decompensation.
PURPOSE: Compensatory responses to focusing errors imposed by spectacle lenses in chicks, tree shrews and primates leave little doubt that active emmetropization can occur, and debate is now centered on whether this process is uni-directional or bi-directional in nature. To provide further insight into this emmetropization process, the studies reported in this paper addressed the question of whether access to sharp vision is necessary for compensation to myopic defocus in the chick. METHODS: Two different experimental paradigms were used to address the above question: (A) Myopic defocus was imposed, either with +15 or +40 d lenses alone or with +15 D lenses on eyes made myopic by 7 days of form deprivation; these treatments result in a shift in the plane of focus of the eye (far point) to 6.67, 2.5 cm and approximately 3.5 cm resp., with only objects at or closer than these planes being in focus. The addition to the lenses of stand-off cones, either 2.5 or 5 cm in length, further limited access to (or precluded) sharp vision by controlling how closely the chicks could approach objects. One group that had sharp vision precluded also underwent optic nerve section. (B) A range of positive lenses (+15 to +65 D) were used on their own to impose myopic defocus; for the high power lenses, access to sharp vision was very restricted because of the close proximity of the new far point (1.54 cm for +65 D lens). Refractive errors and axial ocular dimensions were measured in all experiments. RESULTS: In the first study (A), preclusion of sharp vision not only prevented compensation but resulted in increased eye growth and myopia. This myopia, like form-deprivation myopia, was unaltered by optic nerve section surgery. Limiting but not precluding sharp vision resulted in partial compensation. In the second study (B), good compensation was observed with the +15 D lens but compensation progressively declined for higher powers, with the +50 D lens having no apparent effect on eye growth and refraction and the +65 D lens inducing myopia instead of hyperopia. CONCLUSIONS: Together these results argue that some sharp vision is fundamental to compensation to impose myopia. The significance of this new finding in relation to the processes underlying active emmetropization is discussed.
PURPOSE: The current study compared the central corneal curvature and the refractive error of Hong Kong Chinese to study the validity of Javal's rule. METHODS: Subjects without corneal pathology were recruited at different age ranges. Their refractive error and the corneal curvature were measured and compared for the right eye only. Two instruments were used for the measurement of corneal curvature including a conventional Bausch & Lomb (B&L) keratometer and a computer-assisted videokeratoscope (TMS-1). RESULTS: Subjects age ranged from 21 years to 77 years were recruited and were categorized into five groups according to age. The Bausch & Lomb keratometer was found to provide corneal information similar to that from the TMS-1. The corneal astigmatism was found to change from with-the-rule to against-the-rule with advancing age. The spectacle astigmatism followed a similar trend. There was a hyperopic shift in the spherical component of the refractive error with aging as well. A regression equation: Spectacle astigmatism = 0.93 (Corneal astigmatism) + (-0.58D x 90) was found, which is similar to the simplified Javal's rule. There was a shift of 1.03D in hyperopia (spherical equivalent) for each decade. CONCLUSIONS: Both the corneal and spectacle astigmatism demonstrated a shift from with-the-rule to against-the-rule with age. The simplified Javal's rule is more suitable for predicting the spectacle astigmatism from corneal astigmatism in Hong Kong Chinese.
BACKGROUND: Optic disc elevation associated with Down syndrome is an uncommon phenomenon and raises the suspicion of an intracranial space-occupying lesion, thus necessitating the consideration of invasive and noninvasive investigations. METHOD OF STUDY: Four patients with Down syndrome and optic disc elevation without an underlying intracranial pathology are reported. Thorough ophthalmological and neuroradiological investigations were performed on each patient. Mild hyperopia occurred in three patients and myopia in one. CONCLUSIONS: We believe that in most Down syndrome patients with disc elevation, fluorescein angiography and/or clinical follow-up may be sufficient.
PURPOSE: To examine the pathological significance and familial occurrence of voluntary nystagmus. PATIENTS AND METHODS: We examined two families orthoptically as well as with video and search-coil techniques or electronystagmography (ENG). Three members of three generations of the first family and a 9-year-old boy from a second family not related to the first were able to generate a voluntary horizontal nystagmus. RESULTS: The characteristics of the nystagmus of our original patient, his daughter and 8-year-old grandson (1st family) were remarkably similar: duration of 2-5 seconds, amplitudes of 1-4 degrees and frequencies around 15 cycles/second. In the second family, our patient with a congenital esotropia and hyperopia was the only one of his family who could voluntarily produce a nystagmus of about 5 degrees and 10 cycles/second for maximum of 20 seconds. During prolonged reading, the same nystagmus with disturbing oscillopsia developed involuntarily and was not suppressible. We added +0.75 diopters to both lenses of his spectacles to account for the result of our cycloplegic refraction. This stopped the involuntary nystagmus during near fixation. DISCUSSION: To avoid unintentional "bouts" of voluntary nystagmus, a reduction of the convergence impulse by plus-lenses may be effective. The parameters of voluntary nystagmus can be considered family-specific.
Leber congenital amaurosis (LCA), the most early-onset and severe form of all inherited retinal dystrophies, is responsible for congenital blindness. Ten LCA genes have been mapped, and seven of these have been identified. Because some of these genes are involved in the visual cycle, we regarded the retinal pigment epithelium and photoreceptor-specific retinal dehydrogenase (RDH) genes as candidate genes in LCA. Studying a series of 110 unrelated patients with LCA, we found mutations in the photoreceptor-specific RDH12 gene in a significant subset of patients (4.1%). Interestingly, all patients harboring RDH12 mutations had a severe yet progressive rod-cone dystrophy with severe macular atrophy but no or mild hyperopia.
Conductive keratoplasty (CK) is a new surgical technique for steepening the contours of the cornea to reduce hyperopia. It has been emphasized that during CK, tissue resistance to radio-frequency electrical current flow generates a localized heat with temperatures between 65 and 75 degrees C; however, we hypothesize that the maximum temperature reached in the cornea may be higher. For this reason, we developed a finite-element model to estimate the temperature distributions in the cornea during CK. The time evolution of the impedance obtained from computer simulations was compared to that obtained in an experimental study previously published. Our results show that during a typical CK with a 60% setting power (equivalent to 200 V peak-to-peak), the cornea may reach temperatures over 100 degrees C at the electrode tip. On the other hand, the initial impedance of the cornea has a significant influence on the temperature distribution, while the initial temperature of the cornea is not a significant parameter. The results also suggest that low power settings (30-40%) do not produce temperatures over 100 degrees C. Finally, although the actual voltage waveform during CK is exponential and pulsed, our model based on a constant voltage (with a value equal to the root mean square value) provides a better agreement between the theoretical impedance time evolution and that obtained experimentally.
Senile macular degeneration, although a leading cause of visual loss in the United States, remains a poorly understood disease. To assess the effects of host and environmental factors on this condition, a study of 228 cases and 237 controls matched by age and sex, who had visited any of 34 Baltimore ophthalmologists between September 1, 1978 and March 31, 1980, was conducted. Study participants were interviewed for past medical, residential, occupational, smoking and family histories, as well as social and demographic factors. Diagnoses were validated by means of fundus photographs. The 162 cases and 175 controls who met the study diagnostic criteria for cases and controls were included in the analysis. Statistically significant associations were demonstrated between senile macular degeneration and family history of macular disease (odds ratio (OR) = 2.9), chemical work exposures (OR = 4.2), blue or medium pigmented eyes (OR = 3.5), history of one or more cardiovascular diseases (OR = 1.7), decreased hand grip strength, and hyperopia. The risk of macular degeneration in cigarette smokers was significant for males only (OR = 2.6). The study results suggest that the development of macular degeneration is mainly influenced by familial, genetic, and personal characteristics, rather than by the few environmental factors studied. Additional studies are needed to further evaluate the role of environmental factors.
Primary adenocarcinomas of the lacrimal gland rarely display sebaceous differentiation. An anaplastic lacrimal gland neoplasm manifesting this feature was excised from a 64-year-old man who initially appeared with recurrent painless subconjunctival hemorrhages. Globe displacement and tumor-induced hyperopia were later findings. Electron microscopic studies performed on the widely excised tumor documented prominent lipid vacuoles, desmosomes, scattered cytoplasmic filaments, and linear segments of basement membrane material. The patient refused radical surgery and instead opted for 6,000 rads of adjuvant radiotherapy. Eleven months postoperatively liver and bone metastases developed, but he was free of local orbital recurrence. Twenty-two months postoperatively he died from complications of his metastatic disease. This most unusual lacrimal neoplasm is discussed in terms of its initial signs and symptoms and its histopathology. When the current case is analyzed in combination with three earlier reports, there is evidence that primary lacrimal gland sebaceous carcinoma is probably among the most malignant orbital tumors due to its uniform early fatality.
PURPOSE: This prospective study tested a simple formula for selecting an implant size for patients undergoing enucleation, evisceration, and secondary implantation. The formula axial length-2 mm=implant diameter (subtract 1 mm from implant diameter for evisceration and for hyperopia) was tested by the outcome measures, superior sulcus deformity, enophthalmos, and volume of the prosthesis. METHODS: Fifty-four patients undergoing primary or secondary implant surgery after enucleation or evisceration received implants based on the above formula. The volume of the eye, volume of the implant, volume of the prosthesis, and the total percent volume replacement were recorded for each patient. Outcome measures considered clinically acceptable were <2 mm enophthalmos and less than grade 1 superior sulcus deformity, which is defined as barely perceptible deepening of the medial superior sulcus. RESULTS: The average volume replacement was 101%; average prosthetic volume was 2.1 mL; average grade of superior sulcus deformity was 0.6; and average enophthalmos was 1.2 mm. CONCLUSIONS: This formula allows 100% replacement of the volume removed, leaves space for a prosthesis 1.5 to 2.5 mL, and eliminates clinically unacceptable superior sulcus deformity and enophthalmos in 85% of patients. Patients with a history of infection, radiation, buphthalmos, or large orbital fractures (15%) had residual superior sulcus deformity greater than grade 1 and enophthalmos > or =2 mm despite 100% volume replacement. Further study will elucidate the histopathologic processes responsible for residual superior sulcus deformity and enophthalmos in the latter subgroup of patients.
PURPOSE: To review common complications noted with LASIK. METHODS: Review of personal experience of the author with the procedure and work published in the literature. RESULTS: The most common complications of the LASIK procedure include flap irregularities, epithelium and other materials within the lamellar interface, irregular astigmatism, regular astigmatism, regression, and overcorrection. Infection is a rare but potentially serious complication. CONCLUSIONS: LASIK has impressive potential for the correction of myopia and hyperopia. Surgeons who perform the procedure must be familiar with recognition and treatment of potential complications of LASIK.
PURPOSE: To examine the incidence of sporadic diffuse lamellar keratitis (DLK) in a large series of LASIK eyes and to suggest the hypothesis that the etiology of sporadic DLK differs from that of epidemic DLK. METHODS: The incidence and severity of DLK was noted in 1352 consecutive eyes that had primary LASIK for myopia or hyperopia and 217 consecutive eyes that had LASIK enhancement. RESULTS: Twelve of the eyes having primary LASIK had stage 1 DLK and 5 had stage 2 DLK (.9% total). No eyes had stage 3 or stage 4 DLK. Three of the 217 eyes (1.4%) that had LASIK enhancement had stage 1 DLK. The difference in the rate of DLK for primary LASIK compared with LASIK enhancement was not statistically significant (p = 0.69). All eyes responded to intensive corticosteroid therapy, with the addition of flap lifting and irrigation for the eyes with stage 2 DLK. Two of the eyes (one primary LASIK and one LASIK-enhancement) had implanted epithelial nests associated with the DLK. None of the cases of DLK occurred in eyes of patients who had surgery on the same operating day in this series. Two other eyes that had epithelial abrasions more than 3 months after LASIK or LASIK enhancement developed stage 1 DLK. CONCLUSIONS: Many cases of sporadic DLK, including cases associated with epithelial trauma after LASIK, are likely attributable to endogenous factors that trigger inflammation. One trigger is the release of epithelium-derived cytokines such as interleukin-1 that stimulate keratocytes to produce chemokines that are chemotactic to inflammatory cells. Cells likely accumulate at the interface because it is potential space, representing a path of least resistance for cell movement. Some sporadic cases may also be related to exogenous factors such as Betadine. Epidemic DLK is likely associated with exogenous factors that stimulate inflammation, such as endotoxin contaminating sterilizer reservoirs or detergents on instruments.