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Biomedical subjects

K Psilas

Publications and source records attributed to K Psilas.

At least 19 recordsLinked to original sources

Ocular surface and environmental changes.

PURPOSE: To investigate if ocular surface and precorneal tear film are influenced by the environment. METHOD: We studied the environmental influences on the ocular surface using the tests Break-up time, Schirmer-1 test and Rose Bengal staining. We correlated the values of the above tests among three groups of normal people from different places in Greece with different climates and levels of atmospheric pollution. Group A consisted of 57 persons coming from an area with a dry and warm climate and heavy atmospheric pollution. Group B consisted of 55 normal persons coming from an area with a dry and warm climate and a low level of atmospheric pollution. Group C consisted of 55 persons coming from an area with a humid and cool climate and a low level of atmospheric pollution. RESULTS: Schirmer-1 test and Break-up time are influenced by the climatic conditions but they are not influenced by the atmospheric pollution, while Rose Bengal staining is not influenced either by the climate or by the atmospheric pollution. CONCLUSION: The precorneal tear film is much more influenced by the climatic conditions than by the atmospheric pollution.

Adolescent

What is straight ahead to a patient with torticollis?

Vestibular and neck proprioceptive signals are known to be used in judging the locations of objects in space and relative to the body. Given that these signals are asymmetric in patients with spasmodic torticollis, one would expect such patients to have abnormal spatial perception. We tested this idea by measuring patients' perception of visual straight ahead (VSA) under various conditions: with the body in its primary position, i.e. with the head and trunk as closely aligned as possible, and after well defined passive rotations of the head and/or trunk. In the primary body position, patients' VSA direction showed considerable variations which were similar, however, to those of normal subjects; it was independent of torticollis direction, of the head torque it produced, and of the weak spontaneous nystagmus recorded in seven of the 10 patients. After whole-body rotations, i.e. where head and trunk underwent the same motion, the VSA was shifted in both patients and normal subjects, and in both groups the shift was symmetrical after rotations to the right or left. After motions where the trunk rotated under the stationary head (neck proprioceptive stimulation) or the head on the stationary trunk (combined vestibular and neck stimulus), the VSAs of normal subjects coincided rather well with their head midsagittal planes, whereas the VSAs of patients were shifted considerably towards the trunk, again in a symmetrical way. We suggest two mechanisms to explain the findings in patients: (i) a central compensation which restores symmetry of the afferent inflow in the patients (unlike the motor efference); (ii) shifting of the reference for the VSA from the head towards the trunk, because the trunk is a more reliable egocentric reference than the head in the patients. Our findings do not support the assumption that asymmetries in afferent inflow are responsible for the asymmetry of motor output in spasmodic torticollis.

Adult

Abnormalities of ocular motility in myotonic dystrophy.

Are the oculomotor disturbances in myotonic dystrophy (MD), i.e. reduced smooth pursuit (SP) gain and reduced saccadic peak velocity (PV), of muscular or central origin? To answer this question the following two approaches were used. (i) The performance of SP was compared with the patient's ability to suppress the vestibulo-ocular reflex (VOR) visually (VOR suppression; VOR-S). In the latter task the SP system is involved, but the eyes hardly move within the orbits. A parallel impairment of SP and VOR-S would indicate a central dysfunction. (ii) Peak saccadic velocity was compared between two saccades performed to and fro in rapid succession. The intention was to measure any myotonic effect which might build up after the first saccade and slow down the second saccade. We studied 15 MD patients and 15 age-matched controls. Stimuli for slow eye responses consisted of sinusoidal horizontal rotations of the SP target and/or the vestibular rotation chair at frequencies between 0.1 and 0.8 Hz. Saccades were analysed in terms of PV. accuracy, duration and latency, comparing centripetal versus centrifugal saccades at short and long intersaccadic intervals (ISI; 400 ms and 900 ms, respectively). The SP gain was reduced in patients compared with the controls, the effect being most pronounced (32% less) at the highest stimulus frequency. Whereas VOR was normal in the patients, VOR-S was clearly impaired (50% worse at 0.8 Hz). Despite normal saccadic accuracy, peak saccadic velocity was significantly lower in the patient group (23% less for saccades of 12 degrees amplitude), similarly for centrifugal and centripetal saccades; all these differences were independent of the ISI. Latency was normal with centrifugal saccades, but was considerably increased with centripetal saccades at short ISI (67% longer compared with controls). The observation of a parallel degradation of SP and VOR-S in the patients is interpreted in terms of a central deficit in the SP pathways. Thus, it appears that slow eye movements were not impaired by muscle dystrophy and myotonia to a considerable degree in our patients. The increase in saccadic latency for centripetal saccades at the short ISI also reflects a central deficit. However, the observed slowing of saccades might have a myopathic or neural origin; a distinction was not possible at present. A myotonic origin of the saccade slowing seems unlikely, because the effect was independent of the presaccadic activation of the relaxing (antagonistic) eye muscle.

Adolescent

Exclusion of one pedigree affected by adult onset primary open angle glaucoma from linkage to the juvenile glaucoma locus on chromosome 1q21-q31.

A locus for autosomal dominant juvenile onset primary open angle glaucoma (POAG) was recently assigned to chromosome region 1q21-q31. In the present study, a large Greek family with autosomal dominant adult onset POAG was investigated using microsatellite markers. Exclusion of linkage of the adult onset POAG gene to the region D1S194-D1S191 was obtained in this pedigree. Therefore, the data provide evidence that juvenile and adult onset POAG are genetically distinct disease entities.

Adult

Long-term visual results after laser photocoagulation for diabetic maculopathy.

A study was performed to determine the long-term visual results after laser photocoagulation in diabetic maculopathy. One hundred and four eyes of 56 diabetic patients underwent modified grid laser photocoagulation for diabetic maculopathy according to the protocol of the European Study Group on Diabetic Eye Complications and the Early Treatment Diabetic Retinopathy Study. Follow-up ranged from 12 months to 2.5 years. Eyes with visual acuity less than 0.2 before treatment were included in group A, those with visual aquity of 0.3-0.6 in group B and eyes with visual acuity more than 0.7 were included in group C. At 1 year, 79.4% of the eyes of group A improved or preserved their visual acuity, with 38.9% of group B and 88.2% of group C; at 2 years, 86.6% of group A, 30% of group B and 66.7% of group C and at 2.5 years 85.7% of group A, 27.3% of group B and 75% of group C improved or preserved their visual acuity. The percentages of positive results concerning the visual acuity for groups A and C were significantly greater compared with those for group B. These results suggest that modified grid laser photocoagulation for the management of diabetic maculopathy is an effective procedure in 'early treated' eyes (visual aquity > or = 0.7). It contributes to improve a little or to preserve low vision but it did not affect the natural course of disease in the rest of the eyes.

Aged

Juvenile open-angle glaucoma: a report of a pedigree.

Six patients with juvenile open-angle glaucoma have been studied clinically and genetically in a family pedigree consisting of 17 members. This study revealed that juvenile open-angle glaucoma has an autosomal dominant mode of inheritance and the detected patients showed incipient to severe disturbances of visual function.

Adolescent

Panretinal cryopexy for the management of neovascularization of the iris.

Panretinal cryopexy was used for the treatment of 15 eyes with neovascularization of the anterior segment, treated with panretinal photocoagulation in the past. The eyes were classified preoperatively according to grade of neovascularization of the iris and anterior chamber angle using Weiss' and Gold's device system. Four eyes had rubeosis iridis with normal intraocular pressure and 11 had neovascular glaucoma. Rubeosis was secondary to proliferative diabetic retinopathy and/or central retinal vein occlusion. Nine eyes with grade 0, I and II neovascularization showed regression of neovascularization and controlled intraocular pressure. Six eyes with grade IV showed regression of neovascularization but uncontrolled intraocular pressure. All those eyes presented extensive peripheral anterior synechias.

Aged

HLA-DR antigen expression in pterygium epithelial cells and lymphocyte subpopulations: an immunohistochemistry study.

The purpose of our study was to investigate the role of immune mechanisms in the pathogenesis of pterygium using an immunohistochemical technique. Our material consisted of 35 surgically excised pterygia and 7 samples of normal conjunctiva obtained from an equal number of patients. HLA-DR antigen expression in epithelial cells, B-cells, suppressor and helper lymphocytes, Langerhans' cells, and monocytes/macrophages were studied immunohistochemically in frozen sections using anti-human HLA-DR, anti-CD22, anti-CD8, anti-CD4, anti-CD1a, and anti-LeuM5 monoclonal antibodies. Aberrant HLA-DR antigen expression in epithelial cells was detected in 30 of 35 cases of pterygium. Epithelial cells in samples of normal conjunctiva were found to be negative in HLA-DR antigen expression. HLA-DR antigen expression in pterygium was found to be closely related to the density of T4 cells and, especially, of CD4 lymphocytes. The present findings suggest that an immunopathologic mechanism plays a role in the pathogenesis of pterygium.

Antibodies, Monoclonal

Factors influencing the accuracy of the SRK formula in the intraocular less power calculation.

Several intraocular lens (IOL) power calculation formulas (either theoretical or empirical) are used to determine the emmetropic IOL power) The Sanders-Retzlaff-Kraff (SRK) linear regression formula is among the most widely recognized empirical ones. In the present study intraocular lens power calculation aiming at emmetropia was performed, using SRK formula, in 145 cataractous eyes undergoing lens implantation. The final refraction was evaluated at 8 to 12 months after surgery. The purpose of this study was the identification and quantitative evaluation of the factors which influence significantly the accuracy of SRK in the intraocular lens power calculation. The following factors were studied: (1) the error in preoperative biometry with regard to the difference between post and preoperative axial length measurements, (2) the position of the implantation of the intraocular lens (anterior versus posterior chamber), (3) the intraocular lens style, (4) the intraocular lens power level, (5) the preoperative corneal astigmatism, (6) the surgically induced corneal astigmatism, and (7) the postoperative astigmatism. Multiple regression and stepwise regression analysis showed a strong correlation (R2 = 0.65; p < 0.001) between postoperative refractive error (Rf) and error in preoperative biometry (delta AL), surgically induced corneal astigmatism (SIA) and postoperative astigmatism (Ap) only. This correlation is expressed by the following equation: Rf = 0.07 -2.55 delta AL -0.42 SIA + 0.34 Ap. This equation indicates the quantitative effect of each factor on the accuracy of the SRK formula, by defining the pattern of the fluctuations of the amount or state (myopic or hyperopic) of refractive error induced by changes of variables delta AL, SIA and Ap.

Aged

The cornea in exfoliation syndrome.

Exfoliation syndrome (EXS) is a disorder which affects some structures of the eye. We studied the changes of the cornea in patients with EXS and compared with those in normal persons. A prospective study of 96 consecutive patients more than 70 years of age was set up. 48 of them (70 eyes, group A) had exfoliation in one or both eyes and 48 (group B) had no ocular disease other than senile cataract. None of the patients had any systemic disease. The endothelium and thickness of the central cornea were studied. Endothelium of the eyes with EXS showed significantly (p < 0.05) lower cell density than those of group B. Cornea in group A was significantly thicker (p < 0.05) than in group B. The morphology of the endothelium in group A showed a decrease of hexagonal cells and a higher rate of polymegethism compared to group B. Corneal thickness and endothelium showed no significant differences between the eyes with EXS and normal fellow eyes. These results add another risk factor, the fragile cornea, in eyes with EXS, in cataract surgery.

Aged

The effect of indomethacin, diclofenac and flurbiprofen on the maintenance of mydriasis during extracapsular cataract extraction.

Surgically induced miosis (SIM) frequently occurs during extracapsular cataract extraction (ECCE). A randomized clinical trial was performed to evaluate the effect of 3 nonsteroidal antiinflammatory drugs Indomethacin 1%, Diclofenac 0.1% and Flurbiprofen 0.03%, administered topically before ECCE, on the maintenance of mydriasis during surgery. The patients were grouped based on the type of NSAID given preoperatively in addition to the standard mydriatic agents: 46 patients in group A (Indomethacin), 40 patients in B (Diclofenac), 44 patients in C (Flurbiprofen) and 34 patients formed control group D (no NSAID was instilled). Horizontal pupillary diameter measurements were taken, using a caliper, immediately prior to surgery (step 0), after capsulotomy (step I), after expression of the lens nucleus (step II) and after irrigation-aspiration of the cortical remnants (step III). Differences in pupillary diameter between step 0 and the different surgical steps were used as indices of pupillary constrictions observed in the 4 groups. A significantly less pupillary constriction was found in groups A and C than in D between steps 0 and II (p = 0.01) and in groups A and C than in B and D between steps 0 and III (p = 0.001). Our results show that Indomethacin 1% and Flurbiprofen 0.03%, compared to Diclofenac 0.1% and no NSAID regime, are significantly more effective in maintaining mydriasis during cataract surgery.

Aged

Diagnostic tests for dry eye disease in normals and dry eye patients with and without Sjögren's syndrome.

In order to compare the diagnostic tests for dry eye disease and the results of conjunctival impression cytology, we examined three groups of eyes: 146 eyes of normal controls, 108 eyes of keratoconjunctivitis sicca (KCS) patients without Sjögren's syndrome (SS) and 102 eyes of patients with SS. The clinical tests (break-up time, Schirmer test, Rose Bengal staining) and conjunctival impression cytology specimens from the superior part of the bulbar conjunctiva were evaluated from all the eyes. Our results showed that the patients with KCS without SS have abnormal lacrimal tests (p < 0.001) without changes in impression cytology [nucleo/cytoplasmic ratio (N/C), p > 0.1]. The patients with KCS and SS have also abnormal lacrimal tests (p < 0.01), and their epithelial cells presented squamous metaplasia (N/C, p < 0.001). The goblet cell number remained unchanged in the three groups (p > 0.1).

Adolescent

[Association of progressive external ophthalmoplegia and lattice corneal dystrophy].

The authors conducted a study in a family pedigree comprising 33 patients (men 16, women 17). In this pedigree there coexisted patients with progressive external ophthalmoplegia and corneal lattice dystrophy. Two patients with progressive external ophthalmoplegia and ten with lattice corneal dystrophy were found. One of our patients (propositus) suffered from both diseases. Our study proves that, in this pedigree, progressive external ophthalmoplegia and corneal lattice dystrophy have an autosomal dominant mode of inheritance.

Adult

[Sterile corneal ulcers in dry eye. Incidence and factors of occurrence].

Sterile corneal ulceration is a serious complication in patients with keratoconjunctivitis sicca. The records of 134 patients, 19 males and 115 females, who presented with dry eyes in the Ophthalmologic Clinic were reviewed. Over a period of 6 years, 33 eyes of 23 (17%) patients developed a sterile corneal ulcer. The etiologies of dry eyes in these patients were: Primary Sjogren's syndrome: 10 cases, rheumatoid arthritis: 5 cases, ocular pemphigoid 6 cases, atopy: 1 case, local irradiation: 1 case. Patient's age and sex were not significantly associated with ulcer development (p greater than 0.05). The presence of a major underlying disease was the major contributing factor. Appropriate local treatment and patient compliance were also contributing factors. Blepharitis was found in 90% of patients.

Adult

[Sterile corneal ulcers in dry eye. II. Treatment, complications and course].

Over a period of 6 years, 23 patients (4 males and 19 females: mean age 56 years) who presented dry eyes developed 33 sterile corneal ulcers. Treatment included occlusion of the eyes or bandage soft contact lenses, prophylactic topical administration of antibiotics, punctal occlusions and currently available tear substitutes. Seventeen eyes healed completely without any corneal opacity and 10 eyes healed with opacity. Nine of the 33 eyes developed microbial keratitis. The causes of microbial keratitis were Staphylococcus aureus in 7 cases, beta-hemolytic Streptococcus in one and Pseudomonas aeruginosa in one case. The microbial keratitis was treated with intensive topical antibiotics. In 6 eyes, corneal perforation occurred. Rheumatoid arthritis coexisted in four cases.

Adult

Correlation of conjunctival impression cytology results with lacrimal function and age.

Impression specimens were obtained from the bulbar conjunctiva of 146 eyes of 73 healthy volunteers (mean age, 52 years). Goblet cell densities and nuclear-cytoplasmic (N/C) ratio were determined. Break-up time (BUT), Schirmer-I test (S-I), Rose Bengal scores (RBs) were also recorded. Using a simple linear regression analysis, no correlation between the number of Goblet cells and age, BUT and S-I was found. Negative correlation with RBs (P = 0.05) was found. The N/C ratio has a negative correlation (P less than 0.01) with age and RBs and a positive correlation with BUT (P less than 0.01) and S-I (P = 0.03).

Adolescent

[Familial coexistence of the association: Fabry's syndrome and congenital ptosis].

The authors undertook a clinical and genetic study in a large family with the aim of identifying the mode of inheritance of Fabry syndrome and congenital ptosis. These two types of pathology were present to varying extents. The family pedigree consisted of 95 individuals, spanning 5 generations. Three individuals (males) were found to have Fabry syndrome and 14 (males and females) congenital ptosis. The patients with Fabry syndrome also had congenital ptosis. According to these results, Fabry syndrome is inherited by an X-linked recessive mode and congenital ptosis by an autosomal dominant mode.

Blepharoptosis