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Biomedical subjects

A Tuulonen

Publications and source records attributed to A Tuulonen.

17 recordsLinked to original sources
PubMed1992

Rate and pattern of neuroretinal rim area decrease in ocular hypertension and glaucoma.

The neuroretinal rim areas of 123 eyes (from five normal subjects, 75 patients with ocular hypertension, and 43 patients with glaucoma) were measured to determine the rate and pattern of rim area change during 5 to 15 years (mean, 10 years) of follow-up. Fifty-seven percent of the patients with ocular hypertension and 79% of those with glaucoma showed a statistically significant slope of rim area decrease, a high rate of loss being associated with a high initial rim area. Ninety percent of the variation of rim area loss was accounted for by variables other than the ones measured herein, however (age, disc area, initial rim area, and intraocular pressure). The yearly loss of rim area was 0.23% of the initial area in normal subjects, 0.47% and 2.75% in the patients with stable and deteriorating ocular hypertension, respectively, and 3.47% in the patients with deteriorating glaucoma. The pattern of rim area change was linear in 49% of the patients with a statistically significant rim area decrease, episodic in 22%, and curvilinear in 29%.

Adult↗
PubMed1992

Optic disc size in exfoliative, primary open angle, and low-tension glaucoma.

We examined the magnification-corrected optic disc size in 54 patients with exfoliative glaucoma, 61 patients with primary open angle glaucoma, and 50 patients with low-tension glaucoma. The mean optic disc area in low-tension glaucoma was statistically significantly larger than that in primary open angle and exfoliative glaucoma. The mean values of eyes with primary open angle and exfoliative glaucoma did not differ significantly from each other. Frequency distribution of the optic disc size showed, however, that all three diagnostic groups differed significantly from each other. Small discs were more frequent in eyes with exfoliative glaucoma, and large discs were more frequent in eyes with low-tension glaucoma. In primary open angle glaucoma, small and large optic discs were found equally frequently. It is possible that in some eyes large optic discs are vulnerable to even low intraocular pressures due to qualitative properties of the extracellular matrix.

Aged↗
PubMed1992

The follow-up of patients screened for glaucoma with non-mydriatic fundus photography.

In order to evaluate the value of photographic screening in predicting progressive glaucomatous damage, we re-examined 26 subjects 5 years after the initial screening. Of the 26 patients 16 had typical glaucomatous optic disc and visual field abnormalities (n = 7), retinal nerve layer damage (n = 6), or other risk factors of glaucoma (n = 3). In 10 of 26 patients suspected of having glaucoma, no abnormalities were initially confirmed. Of the 16 eyes with initially abnormal findings, 10 (63%) showed progressive changes during the 5-year follow-up period. The 10 initially suspected cases have remained healthy throughout the follow-up, giving a false positive rate of 5.5%. The results of this study indicate that it is possible to identify correctly patients with progressive glaucomatous changes with a non-mydriatic fundus camera.

Female↗
PubMed1992

Neuroretinal rim area measurements by configuration and by pallor in ocular hypertension and glaucoma.

PURPOSE: The purpose of this study is to examine the differences between measurements of neuroretinal rim area of the optic disc defined by configuration and by pallor. METHODS: One hundred seventy-one patients were studied (59 with glaucoma, 96 ocular hypertensive patients, and 16 controls). The magnification-corrected neuroretinal rim area was measured from black-and-white stereoscopic paper prints. The central area of pallor was measured using computer-assisted image analysis techniques. The percentage of central area of pallor was converted into mm2, and an estimate of neuroretinal rim area defined by color was calculated. RESULTS: The correlation between the measurements of neuroretinal rim area by configuration and by pallor was statistically highly significant (r = 0.89, P less than 0.0001). No consistent differences between measurements were found in different diagnostic groups, or in different stages or types of glaucomatous optic disc abnormality. The correlation of changes of both measurements during a 9-year follow-up period also was statistically significant (r = 0.68, P less than 0.001). CONCLUSION: In clinical routine measurements of the neuroretinal rim area, using both configuration and pallor definition does not seem to add to the information.

Adult↗
PubMed1992

Light scatter in aging and cataractous human lens.

We measured back light scattering of the human lens with the Lens Opacity Meter 701 in order to determine whether it can be used for objective assessment of lens opacities in various types of cataracts. One-hundred and twenty-seven eyes of 127 individuals were examined including 43 healthy volunteers in various age groups and 84 patients with cortical, nuclear, posterior subcapsular or mixed lens opacities. Almost 90% of the total variation in the light scatter values was accounted for by age in non-cataractous eyes. Mean scatter value of every cataract group was statistically significantly higher than that of age matched healthy controls (p less than 0.0001). Highest scatter values were measured in cortical cataracts while the mean values of other types of cataract were not statistically significantly different from each other. The regression between light scatter and visual acuity was statistically significant for each cataract group. However, large variation of visual acuity was found with scatter values below 60. The results indicate that the Interzeag Lens Opacity Meter is able to identify cataractous and non-cataractous eyes and discern at least advanced cortical cataracts from other types of lens opacities.

Adolescent↗
PubMed1992

[How is simplex glaucoma diagnosed?].

Although glaucoma has traditionally been regarded as a disease affecting people over 60 years of age, improved diagnostic methods now enable glaucoma-related changes to be detected already in the 35-40-year-old age group, long before any functional visual changes are present. Since there is no treatment capable of restoring lost visual capacity, the diagnosis should be made and treatment initiated at an early stage before visual deterioration has become manifest. Measurements of intra-ocular pressure and visual acuity provide insufficient guidance, whereas periodic photography of the nerve fibre layer yields early diagnostic information and an indication of the appropriate individual level of intra-ocular pressure to prevent progression of the disease.

Glaucoma, Open-Angle↗
PubMed1991

Initial glaucomatous optic disk and retinal nerve fiber layer abnormalities and their progression.

We attempted to identify the initial glaucomatous changes of the optic disk and retinal nerve fiber layer and to analyze how these changes subsequently progressed. Of 61 eyes of 61 patients with ocular hypertension, 23 (38%) developed glaucoma during ten years of follow-up (range, five to 15 years). The initial sign of glaucomatous damage was diffuse enlargement of the optic disk cup in ten of 23 eyes or generalized thinning of the nerve fiber layer without localized changes in 12 of 23 eyes. We found localized optic disk damage in ten of 23 patients and localized retinal nerve fiber layer damage in 11 of 23 patients alone or in combination with diffuse damage. In 13 of 23 eyes, the cupping ended up in diffuse enlargement with even more profound thinning of the neural rim in the upper and lower temporal disk margins. There seems to be great variability in the appearance and progression of the initial glaucomatous optic disk and nerve fiber layer abnormalities in patients with increased intraocular pressure.

Adult↗
PubMed1991

Lens autofluorescence in healthy individuals.

We measured blue-green autofluorescence (AF, 495 nm/520 nm) of the lens in 43 random eyes of 43 healthy volunteers aged 6-86 years, five in each decade, using an instrument designed by one of us (HN). The instrument generates an autofluorescence profile, which consists of anterior and posterior juxtacortical peaks and a central plateau. The height of the anterior peak was taken as a maximum autofluorescence value and the square root of the ratio between the posterior and the anterior peak was used as a lens transmission index. The coefficient of variation for the measurement technique was 3.9% for maximum autofluorescence and 2.9% for lens transmission index. Both the maximum autofluorescence and the transmission index were highly correlated with age. Statistically over 90% of the variation in maximum autofluorescence values and almost 70% of the variation in transmission could be attributed to age.

Adolescent↗
PubMed1991

Neuroretinal rim area in low tension glaucoma: effect of nifedipine and acetazolamide compared to no treatment.

The purpose of this study was to measure the change of neuroretinal rim area in patients with low tension glaucoma on- and off-treatment. Thirty-two patients were followed up for a mean of 2.6 years. Ten patients received treatment with nifedipine, 11 patients with acetazolamide and 11 patients had no treatment. The total change of rim area and the yearly rate of rim area change did not differ statistically significantly between the three groups. Seven patients in each group suffered from cold hands and feet. The response to cold provocation visual field testing was positive in 25% of patients. Neither the history of cold hands and feet nor the cold provocation test result affected the rate of progression of optic disc abnormalities. Nifedipine and acetazolamide treatment seemed to show no advantage over no-treatment in our patients.

Acetazolamide↗
PubMed1990

The effect of jogging on visual field indices.

The Humphrey 30-2 visual field was examined 9 times before and after an 8-km jog in one subject, whose contrast sensitivity had been found to improve after jogging. The mean deviation improved statistically significantly suggesting better sensitivity of the visual system after jogging. Our results suggest that in some individuals physical exercise influences the factors which lie behind the visual field long-term fluctuation.

Contrast Sensitivity↗
PubMed1990

Screening for glaucoma with a non-mydriatic fundus camera.

183 first-degree relatives of glaucoma patients were photographed by a technician with non-mydriatic fundus camera in order to study the suitability of wide angle black-and-white fundus photographs in screening for glaucoma. The success rate of photography was 92%. The optic disc and retinal nerve fiber layer abnormalities were evaluated from the photographs by an ophthalmologist. 31 subjects (17%) were referred to further ophthalmological examinations. We found 6 (3%) new glaucomas. In addition, in 6 patients (3%) retinal nerve fiber layer defect was the only abnormality, 5 subjects (3%) showed a hemorrhage and 2 eyes had collateral vessels as a sign of asymptomatic venous stasis change at the optic disc. Only 1 of the 6 (17%) patients with glaucoma would have been found with tonometry alone. The results of this study indicate that non-mydriatic retinal camera is a useful tool in screening for glaucoma.

Adult↗
PubMed1990

Retinal nerve fiber layer abnormalities and high-pass resolution perimetry.

The purpose of this study was to compare high-pass resolution perimetry (HRP) test results with clinical optic disc measurements and semi-quantitative retinal nerve fiber layer (RNFL) estimates. HRP reflects the separation of functional ganglion cells in the retina, and estimates a 'Functional Channel Fraction (FCF)' index that expresses the number of functional ganglion cells relative to average normal. FCF was statistically highly significantly correlated both with the overall and diffuse RNFL score (r = -0.63, P less than 0.0001) and with the neuroretinal rim area (r = 0.44; P less than 0.001). This suggests that HRP is a useful psychophysical test to assess optic nerve integrity in glaucoma.

Adult↗
PubMed1990

Molteno implant surgery in uncontrolled glaucoma.

Molteno implant surgery was performed on 33 eyes of 29 patients with complicated and uncontrolled glaucoma. Average preoperative IOP was 34.0 +/- 8.8 mmHg. After a mean postoperative follow-up period of 18.3 months the IOP was 15.8 +/- 8.3 mmHg. Three patients had an IOP over 22 mmHg. Overall, success rate was 73% with IOP and medication as criteria. In 75% of eyes visual acuity improved or remained within two lines of the preoperative value. The highest success rate was 83% (10 of 12 eyes) in congenital and uveitic glaucoma when both IOP, medication and visual acuity were taken into account. At the end of the study 52% of eyes were controlled without medication. Complications included transient hyphema (21%), flat anterior chamber with hypotony, with or without choroidal detachment (12%), tube touch to lens or cornea (9%), and tube block with vitreous (3%).

Adolescent↗
PubMed1989

Asymptomatic miniocclusions of the optic disc veins in glaucoma.

This study was done to document photographically the evolution of asymptomatic venous stasis changes of the optic disc in glaucoma, estimate their prevalence, and report the clinical findings. Asymptomatic venous miniocclusions were found to develop and occasionally disappear in the optic disc stereophotographs of nine patients with early to moderate glaucoma or ocular hypertension during a mean follow-up of 9 years. In the 1664 photographs examined, a prevalence of 3% was found. None of the patients had a history of retinal vein occlusion or venous stasis retinopathy. Progression of glaucomatous optic disc changes occurred in eight of nine patients. It is possible that asymptomatic miniocclusions are secondary to the changes at the bottom of the optic cup. The miniocclusions, which are easily missed if not looked for, may be an early indicator of glaucomatous progression of the optic disc cupping.

Adult↗
PubMed1989

Laser trabeculoplasty versus medication treatment as primary therapy for glaucoma.

The first-year results of a 5-year prospective randomized follow-up study on 39 glaucoma patients, of whom 19 patients received laser trabeculoplasty and 20 patients medication therapy as primary treatment of their newly detected open-angle glaucoma, are presented. The optic disc changes were recorded by measuring the magnification corrected neuroretinal rim area from stereoscopic optic disc photographs and the visual field changes with an automated perimeter. There were no statistically significant differences in success rate, intraocular pressure reduction, and optic disc or visual field changes between the two groups during the first year of follow-up. In half of the laser treated patients the intraocular pressure was below 22 mmHg without medication treatment. Many patients in the medication group required frequent modifications of their therapy. Laser trabeculoplasty has an important role as primary therapy in glaucoma.

Acetazolamide↗