Biomedical subjects
Publications and source records attributed to R Autrata.
Retinoblastoma is one of the most frequent ophthalmological tumours in children. It is an embryonic tumour originating in the retina. It is caused by abnormalities in the RB1 gene and deletions in the region 13q14. The authors present a bilateral non-hereditary retinoblastoma in monozygotic twins, associated with deletion in the region 13q14, stigmatization, psychomotor and somatic retardation.
The author evaluates in a retrospective study the incidence, diagnosis and causal agent and therapeutic results of microbial inflammations of the orbit. During the period from Jan. 1 1997 till Dec. 31 1999 66 children were hospitalized with the diagnosis of inflammation of the orbit. The mean age of the children was 6.2 years, the mean period of hospitalization 10.2 days. Chandler's classification of inflammations of the orbit was used. The diagnosis was established in collaboration by an ophthalmologist, otolyryngologist and roentgenologist. The main cause of inflammations of the orbit was inflammation of the paranasal sinuses. The most frequent microbial agents were streptococci, staphylococci and Haemophilus influenzae. All patients were treated during hospitalization by antibiotics administered by the i.v. route. Surgery was necessary in 8 patients--in 4 patients with an orbital abscess and in 4 patients with a subperiostal abscess not responding to conservative treatment. The operation was performed by an otolaryngologist using always the endonasal approach. The authors did not record in their group any permanent ophthalmological complications resulting from the inflammation of the orbit.
In a retrospective clinical trial is compared efficacy of transscleral cryotherapy versus diode laser photocoagulation in the treatment of threshold stage 3 retinopathy of prematurity (ROP) in zone II-III. 40 eyes were treated with cryotherapy and 32 eyes were treated with diode laser photocoagulation. All children have been followed up for 5 to 9 years after treatment. The long-term best-corrected visual acuity (BCVA) and refractive errors were evaluated. BCVA from 6/6 to 6/18 in last examination had 53% of eyes with cryotherapy and 56% of eyes with photocoagulation. The difference was not statistically significant (P = 0.094). Myopia over -6.0 D were at 32.5% of eyes with cryotherapy and at 22% of eyes with photocoagulation. This difference was statistically significant (P < 0.05). In the second part of this study is evaluated the long-term visual acuity and structural outcome in Zone 1 ROP (Very posterior Zone 1 disease, rush disease). 20 eyes with cryotherapy and 24 eyes with photocoagulation of this severe form ROP were followed up for 5 to 11 years. BCVA of 6/36 and better had 30% eyes of cryotherapy and 37.5% eyes of laser photocoagulation (P < 0.05). Unfavourable structural fundus outcomes had 55% eyes of cryotherapy and 33% eyes of photocoagulation (P < 0.05). These differences were statistically significant. Our results support the long-term efficacy and safety of cryotherapy and diode laser photocoagulation in the treatment of threshold 3 stage ROP. Visual acuity results suggest that diode laser photocoagulation is as effective as cryotherapy in treatment of this ROP stage. In the group of posterior Zone 1 ROP was achieved better visual acuity results and reduced unfavourable structural outcomes with diode laser photocoagulation as compared to cryotherapy.
In a retrospective study of 397 children operated in the course of 10 years (1985-1995) on account of essential infantile esotropia the authors evaluate the effect of early surgery implemented before the age of two years on the quality of binocular vision as compared with a later operation. The group of children was divided into three sub-groups. Group A comprised 75 children with the operation during the first six months of life (mean 3.8 months), sub-group B 194 children with the operation at the age of 6-24 months and in group C 128 children operated at the age of 2-6 years (mean 3.56 years). In group A binocular vision was recorded in 80% children (15% superposition, 60% fusion, 5% stereopsy). In groups B binocular vision was recorded in 76% children (18% superposition, 50% fusion, 8% stereopsy). In group C simple binocular vision in the form of superposition was present in 24% and fusion only in 21% children. The results of binocular vision after surgery of essential infantile esotropia are in favour of early surgery, preferably by the age of 6 months, not later than at the age of 2 years. An essential part of comprehensive treatment is active and positive pleoptic and orthoptic care incl. supplementary surgical correction of residual horizontal or vertical deviations. Early surgery of an adequate extent with a safeguarded parallel position of the eyes implies in the long run more frequent achievement of a higher quality of binocular vision incl. stereopsy.
Retrospective clinical trial evaluated efficacy and safety of phototherapeutic keratectomy (PTK) within 35 children (35 eyes) aged 8 to 18 years (mean 12.6 years). All children had a long time postoperative follow-up ranged from 2 to 5 years (mean 3.2 years). Indications for PTK in children were: recurrent corneal epithelial erosion syndrome, superficial scars after keratitis "e lagophthalmo", dry spots and mucous plaques after atopic- vernal eye disease, band keratopathy, anterior corneal dystrophies, corneal scars secondary to post-infectious keratitis (post-herpes simplex corneal scarring) and following trauma. The aim of treatment were to improve visual acuity and to reduce or eliminate subjective ocular discomfort-pain, lacrimation and photophobia. Fully informed parents consent was done at all cases. There was increased the best spectacle corrected visual acuity (BSCVA) in all Children, and episodes of ocular pain, lacrimation and photophobia diminished. The mean preoperative BSCVA 6/36 (ranged from 6/9 to 1/60) improved to mean value 6/12 (ranged from 6/6 to 6/60) as 2-5 years follow-up postoperatively. Seven children had 5 or more Snellen's lines gain of the BSCVA, ten children gained 4 lines, eight children gained 3 lines and five children gained 2 lines postoperatively in comparison to their preoperative values. At four cases were evaluated only 1 line gain of BSCVA, one eye unchanged, and no eye had BSCVA worsened after PTK. Phototherapeutic keratectomy in children seems to be an effective and safety procedure in the management of suitable anterior corneal disorders. Our clinical results suggest the most suitable diagnoses for treatment include recurrent corneal epithelial erosions, band keratopathy, dry spots, mucous plaques, anterior corneal dystrophies, and anterior post-keratitis and post-traumatic scars.
PURPOSE: To evaluate quality of binocular vision in dependence on type of cataract, time of surgery and type of aphakic correction with minimal 5 years follow up. METHODS: 127 children divided into 3 groups: Group A--24 children with monolateral congenital cataract, Group B--56 children with bilateral congenital cataract, Group C--47 children with traumatic cataract. Binocular vision results were evaluated 5-10 years after cataract surgery subordinated on the type of aphakic correction-PC IOL, contact lenses, spectacles, type of cataract (congenital mono or bilateral, traumatic) and time of cataract surgery. RESULTS: Group A: Binocular vision in 56% children with cataract surgery in the first 3 months of age and only 20% of binocular vision in children operated later. Binocular vision results in dependence on aphakic correction (46% in contact lens subgroup, 44% in PCIOL subgroup without statistically significant differences. Group B: Binocular vision in 76% of children operated in the first 3 months of age, and 79% of children operated later. Binocular vision in 68% of children in spectacle aphakic correction subgroup, 67% of children in contact lenses subgroup, and 75% of children in primary or secondary implanted PC IOL subgroup. Group C: Binocular vision in 80% of children with contact lenses subgroup, and in 84% of children with implantation PC IOL. CONCLUSION: Better results of binocular vision quality have children with cataract extraction in the first three months of age then children operated later in group with monolateral congenital cataract. Primary or secondary implantation of PC IOL was find to the better aphakic correction for the binocular visual results in the groups with bilateral congenital cataract and traumatic cataract than other types of aphakic correction. Amblyopia is a major determinate of visual outcome in childhood cataract. The timing of surgery--the early cataract removal will continue to be more important than the method of aphakic optical correction, especially in the case of monolateral congenital cataract.
A new lens coupling television (TV) system using a YAG (Yttrium Aluminum Garnet: Y(3)Al(5)O(12) : Ce(3+)) single crystal screen has been developed for a high-voltage electron microscope (HVEM), and its performance is examined. The system, using a combination of YAG and lenses, is less damaged by high-energy electron irradiation and reduces the influence of X-rays on the image. YAG screens have not been used for lens-coupling systems, because the high refractive index (n = 1.84) of YAG results in a low light collection efficiency for emitted light. This disadvantage is overcome by combining a thin YAG disk screen (thickness; 100 microm) with a glass hemisphere whose refractive index is 1.81. We found that the light intensity is almost the same as that obtained with a conventional P22 powder screen and lenses system. The resolution is about 55 microm on the YAG screen, and this value is 1.3 times higher than that measured by the conventional system. Shading and distortion do not affect TV observation. Detection quantum efficiency, obtained after correction of the channel mixing effect, is about 0.1.
OBJECTIVE: To evaluate the results of primary and secondary implantations of intraocular lenses (IOL) in children--visual acuity, binocular function, resulting refraction and complications after operation. METHODS: The group comprises 47 eyes of 36 children operated in 1993-1997, aged 5-16 years (mean age of operated children 10.3 years). The follow up period after operation was 18-60 months. The mean follow period was 37 months. Twenty-two primary implantations of posterior chamber IOL were made and 25 secondary implantations, incl. 13 posterior chamber IOL and 12 anterior chamber IOL. From the total number of cataracts 26 were traumatic and 21 congenital (16 bilateral and 5 unilateral). RESULTS: A visual acuity of 6/12 or better was recorded after operation in 31 (67%) eyes, incl. vision 6/6 in 7 eyes. Vision 6/15 to 6/24 was found in 8 (18%) eyes. Binocular function after operation was recorded in 26 (73%) children. Of these 11 have stereopsis and 15 have fusion I-III. Nine children (27%) do not have binocular functions. Half the eyes have after operation a refraction within the interval +/- 1.0 D SE. Fifteen eyes (33%) are within the range of +/- 2 D SE from emetropy. Eight eyes had a refraction in the interval of +/- 3 D SE during the last check-up examination. The most frequent postoperative complication was a slight (48%) or more serious (23%) inflammatory reaction, decentration of the IOL (23%), and in case posterior capsulotomy was not performed during primary implantation, the complication in almost 8% of eyes was secondary cataract which had to be treated by capsulotomy with a NdYAG laser. One intraocular lens had to be explanted. CONCLUSION: Implantation of an intraocular lens in children aged 5-16 years is according to the results of postoperative visual acuity and binocular functions a suitable alternative of correction of child aphakia.
The authors evaluate the results of photorefractive keratectomy in children with high myopic anisometropia proved by intolerance of a contact lens and intolerance of full correction by glasses. The objective was to maintain or improve the already achieved binocular vision without or with feasible correction by glasses. The group is formed by 13 children, mean age 11.5 years at the time of surgery (range 7-15 years). The mean preoperative value of myopia was -8.9 dpt (SE), within the range of -7.0 to -11.75 dpt (SE) on the operated eye. The preprequisite condition for surgery was confirmed intolerance of a contact lens, intolerance of complete correction by glasses and previous systematic pleoptic treatment with training of binocular functions. The operation was always implemented during hospitalization. The follow-up after surgery in all children of the group is more than 2 years. The mean value of the refraction defect two years after surgery is -1.12 dpt (SE). The mean non-corrected visual acuity improved from 0.021 before surgery to 0.48 two years after surgery and the mean best corrected visual acuity improved from 0.51 before surgery to 0.61 two years after surgery. The authors compare results of binocular functions before and after operation. Two years after surgery all children had superposition and a normal Bagolini test, 12 children had fusion I, 9 children fusion II, and 6 children fusion III and stereopsis. Based on the results of the trial PRK appears to be an effective and safe method for correction of high myopic anisometropia in intolerance of contact lenses or complete correction by glasses. This operation thus makes it possible to preserve further the degree of binocular vision practised in advance or to improve it. This is the first group, though small, of thus treated children published in our professional literature.
The authors evaluate the results of 257 scleroplastic operations performed in 145 children with progressive myopia in 1989-1995. The age range of the operated children was 5-17 years. The mean age at the time of operation was 10.4 +/- 3.9 years. The children were followed up for at least two years before and two years after operation. All children met the condition of progressive myopia, minimal refraction -6.0 D and progression of at least 1 D per year during the last two years before surgery. The authors investigated the axial length of the bulbus by biometry, objective and subjective refraction, the best corrected visual acuity before and after surgery. The mean progression of myopia two years after the scleroplastic operation declined to a mean value of 0.29/year. No serious complications were recorded. Scleroplasty can be considered a safe surgical method which can help to improve the unfavourable development of progressive myopia.
The authors present data on problems associated with the diagnosis of orbital rhabdomyosarcoma in children. They analyze a ten-year period during which they verified in a department of child ophthalmology the disease in four children. The presence of the tumour is one per 60,000 out-patient examinations and during the follow-up period it had a seven times rarer incidence than retinoblastoma. The authors emphasize the varied clinical picture of the tumour and its differential diagnostic pitfalls and the possibility of mistaking temporarily the tumour for inflammatory or post-traumatic orbital changes. The authors remind of the necessity to consider the possible presence of rhabdomyosarcoma in all rapidly growing tumourous orbital processes, in particular in young children.
In a group of 1037 operated eyes the effectiveness, predictive value, stability and safety of photorefraction keratectomy by means of an excimer laser was tested in myopia (PRK) and astigmatism (PARK) with a two-year follow-up period after operation. The range of the preoperative refraction defect was -1.75 to -2.10 dpt (SE). The maximal value of the corrected cylinder in astigmatism was -6.0 cyl dpt. In the PRK group 459 operations were evaluated, in the PARK group 578 operations. Both groups are classified according to the spherical equivalent of the refractory defect into three groups. Group A is formed by myopia up to -6.0 dpt, group B myopia -6.25 to -10.0 dpt and group C above -10.25 dpt. Non-corrected visual acuity 6/12 and better was recorded in the 20th month after operation in group A in 93.4-97.6% (PARK-PRK) operated eyes, in group B 88.7-91.5% and in group C 61.2-68.4% of operated eyes. The achieved final refraction (SE) in an interval +(-1.0) dpt from the originally planned one was recorded during the 20th month after operation in group A in 92.8-96.5% (PARK-PRK) operated eyes, in group B 73.5-78.9% and in group C 59.7-63.5% operated eyes. The best corrected visual acuity (NKZO) in the whole group 20 months after operation was unaltered or better by 1 line of projected optotypes as compared with NKZO before operation in group A in 97.6%, in group B in 94.3% and in group C in 89.7% operated eyes. The analysis of results in PRK and PARK in the group with a two-year follow-up period after operation permits to evaluate the method as sufficiently effective and safe for correction of myopia up to -10.0 dpt but less predictive in myopia above -10.0 dpt.
The authors evaluate the results of photorefractive keratectomy by means of an excimer laser myopia and astigmatism in 343 eyes with a minimal follow-up period of 9 months. The value of the preoperative refractive error expressed in spherical equivalents was -1,75 to -18,5 d. In astigmatism the maximal value was -5 cyl. d. The group was divided into four sub-groups: A) -1,75 to -3,0 d., B) -3,25 to -6,0 d., C) -6,25 to -10,0 d., D) more than -10,25 d. The spherical equivalent of the refractive error 9 month after operation was -0,28 d. in group A, -0,37 d. in group B, -0,67 d. in group C and -1,82 d. in group D. Uncorrected vision, 6/12 or better, 9 mons after operation was recorded in group A in 98,1% patients, group B 95,6% group C 91,2% and in group D in 72,5% patients. The authors proved a high effectiveness, safety predictability and stability of photorefractive keratectomy by means of an excimer laser in myopia up to -10 d. Photorefractive keratectomy is a promising method which extends the possibilities of correcting myopia and astigmatism in sufficiently positively motivated and indicated patients.
Double Layer Coating for backscattered electron imaging is a coating and imaging method especially suitable for high resolution scanning electron microscopy (SEM) of large biological samples. Since the backscattered electron (BSE) signal from thin metal coating layers is quite low, field emission SEM's and very sensitive BSE-detectors are required for this method. In this study an improved BSE-detector of the YAG type was used with an in-lens type field emission SEM. Two samples were investigated in order to demonstrate and to improve the potential of this new approach: (1) cryo-prepared cultured kidney cells were shadowed by electron beam evaporation with platinum-carbon (unidirectionally at a fixed angle of 45 degrees) and then coated with an additional 10 nm carbon layer; and (2) cryo-prepared trichocyst matrixes (paracrystalline structures contained in secretory granules, the trichocysts, found in Paramecium) were coated by ion beam sputtering with about 1 nm of platinum. This sample was rotated and tumbled during coating in order to obtain as uniform a metal layer as possible and then an additional 10 nm carbon layer was evaporated over the metal. When these samples were viewed at a primary beam accelerating voltage (Vo) of 10 kV or higher, contrast was good on the unidirectionally coated cell culture samples. However, trichocyst matrixes with the thinner and more uniform coating showed very poor contrast because most of the BSE detected represented beam-specimen interactions from the bulk of the sample and not in the thin platinum layer. The situation was improved by using low Vo (4 kV). Under these conditions the penetration depth of the electrons is reduced and a greater proportion of the BSE electrons are scattered by the platinum layer. The results were compared with freeze-fracture and deep-etch transmission electron microscope studies of the trichocyst matrixes from the literature: Almost similar resolution is achieved on the biological structures but a better impression of the three dimensional arrangement of the whole trichocyst matrix is obtained with the SEM. The globular particles form disc-like structures that are connected with each other by thin fibers.
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Epidermal growth factor receptors (EGFR) were labeled with 10 nm immunogold and examined on uncoated specimens of A431 human epidermoid carcinoma cells. A field emission gun and a high-sensitivity YAG ring detector were used to demonstrate the affinity labeling simultaneously in the secondary-electron (SE) and backscattered-electron (BSE) modes with a low accelerating voltage (Vo). At Vo = 2 kV, the SE and BSE signals were too weak to identify all markers, while at Vo = 3-7 kV labeling was observed unambiguously in both the SE and BSE modes with smaller and higher working distances. Increasing the Vo to above 7 kV sometimes provokes instability of the specimens. A Vo of > or = 10 kV produces charging artifacts in the SE image, but permits a BSE image of the gold markers providing additional topographic information. In conclusion, immunogold labeling can be used with good results for uncoated specimens.
We evaluated efficacy and complications of diode laser cyclophotocoagulation in pediatric patients with refractory glaucomas. The retrospective study comprised 69 eyes of 53 pediatric patients with uncontrolled refractory glaucoma treated by transscleral diode laser cyclophotocoagulation. The mean age was 6.1 +/- 4.29 (range 0.9-15) years. The main parameters evaluated were: intraocular pressure (IOP), visual acuity, and complications. The mean follow-up period was 5.6 +/- 2.8 (range 2.2-9.5) years. Treatment success was defined as a postoperative IOP of </=21 mm Hg, with or without adjunctive glaucoma medications. The baseline mean pretreatment IOP was 34.08 +/- 7.13 (range 24-47) mm Hg. The final mean postoperative IOP was 20.81 +/- 6.38 (range 12-33) mm Hg after a mean of 2.13 +/- 1.47 (range 1-6) laser procedures. After one treatment session, 66% of the eyes had a successful reduction in IOP (</=21 mm Hg), but this had fallen to 41% by 1 year. With repeat cyclophotocoagulation, 79% of the eyes had a clinically effective reduction in IOP(</=21 mm Hg) for 1 year (mean 7.1-month interval between treatments). Postoperative complications included choroidal detachment in 4 eyes and retinal detachment in 2 eyes with progression of vision loss. All these complications occurred in aphakic patients. Cyclophotocoagulation by diode laser is a useful therapy for the treatment of refractory pediatric glaucomas with uncontrolled IOP. Cyclodiode repeated treatment can provide effective control of IOP with a low risk of severe complications. Aphakic patients may have an increased risk of postoperative complications.