Anna Polizzi

Echobiometric study of ocular growth in patients with amblyopia.

BACKGROUND The natural evolution toward emmetropia is governed by genetic factors, but experiments with animals have demonstrated that a feedback mechanism that depends on visual function may regulate ocular growth. We attempted to verify this hypothesis in school-age patients with amblyopia by observing the ocular growth and the refractive state in the fixating and nonfixating eye in myopia and hypermetropia. This situation simulates the animal model. METHODS In 30 consecutive school-age patients with amblyopia, we prospectively evaluated axial length with echobiometry and the refractive state during cycloplegia induced by atropine. RESULTS We found a statistically significant increase in axial length in the fixating eye of patients with hypermetropia compared with the amblyopic eye (P = .0008). In patients with myopia, we found less of an increase in axial length in the fixating eye compared with the amblyopic eye (P = .0048). CONCLUSION Good vision seems to influence the evolution of ocular growth toward emmetropization.

Pigmentary retinal dystrophy associated with pigmentary glaucoma

Two young brothers were bilaterally affected by pigmentary glaucoma and extensive symmetrical changes of the retinal pigment epithelium (RPE). Fundus changes consisted in widespread salt-and-pepper RPE mottling and pigment clumping, sparing only the peripapillary and foveal areas. During the course of 4 years, one of the two patients suffered multiple, recurrent, exudative and hemorrhagic detachments of the RPE that involved the midperiphery and posterior pole. No exudative lesions appeared in the brother. The medical history and systemic laboratory tests were noncontributory in both patients. The ERG was normal and the EOG subnormal. Dark adaptation was delayed and showed an elevation of the scotopic threshold. These cases seem to support the hypothesis that the RPE is also involved in the pigmentary dispersion syndrome. An inherited defect could affect the pigment epithelium in both the anterior and posterior segments of the eye. The multifocal subretinal exudative pattern that occurred in one of our patients has not been previously observed in hereditary disorders of the RPE.

Echographic study of extraocular muscle thickness in children and adults.

Background Echobiometric evaluation of extraocular muscles in normal subjects has been performed previously, but only in adults. We determined extraocular muscle thickness in normal subjects in three age groups.Methods Extraocular muscle thickness was studied in 75 normal subjects divided into three age groups (5.10, 11.15 and 28.37 years) using a Biovision B-scan-S instrument in standardized A-mode (frequency, 10 MHz; biometry resolution, 0.15 mm; depth, 40.60 mm; points on X axis, 512; levels on Y axis, 256). All measurements were performed by the same operator and repeated five times. The reproducibility of the technique was determined using the coefficient of variation. The one-way ANDV A test was used to compare the three groups, and the two-tailed unpaired t-test was used to compare subjects aged 5.10 years and those aged 11.15 years, and subjects aged 11.15 years with those aged 28.37 years.Results The technique showed good reproducibility. In subjects 5.10 years old, the coefficient of variation was 8%; in subjects 11.15 years and 28.37 years old, it was 5%. Increased muscle thickness was observed with age (p < 0.001). A statistically significant difference between the medial and inferior recti muscles in subjects 11.15 years and 28.37 years old was found (p < 0.001).Conclusions The increased thickness of all recti muscles may be influenced by growth (primarily during puberty), and the variations in thickness of the extraocular muscles may be attributable to near-vision stimulus of the inferior and medial recti muscles.

The macular recovery test after photostress in normal and diabetic subjects

SummaryThe authors present a clinical statistical study on the macular recovery test after photostress in normal subjects and retinopathic and non-retinopathic diabetics. The limits within which the test retains its reliability in predicting the development of retinopathy in diabetics are statistically analyzed.

Role of impression cytology during hypovitaminosis A

AIMS Evaluation of the morphological damage to the ocular surface of patients operated for biliopancreatic diversion for pathological obesity and the correlation of impression cytology with vitamin A plasma levels, adaptometry, and other general variables. METHODS 48 patients (15 males, 33 females, age range 21–73) and 34 normal subjects were examined with fluorescein and rose bengal, a plasma dose of vitamin A, and adaptometry. The results of the various tests were subdivided into three levels (0 = normal, 1 = moderately altered, 2 = seriously altered). The impression cytology and adaptometry results were correlated with vitamin A levels and other patient data (age, nutritional condition, time since operation, percentage weight loss). All the examinations were repeated after intramuscular therapy with vitamin A. RESULTS Corneoconjunctival alterations visible with fluorescein and rose bengal staining were present in 67.7% of cases, impression cytology alterations in 93.7%, adaptometric alterations in 82.2%; vitamin A plasma levels were below normal in 95.8% of cases. After the therapy with vitamin A a significant reduction was found for every examination. The correlation between impression cytology and adaptometry and vitamin A plasma levels and between corneoconjunctival alterations and vitamin A plasma levels was significant. There was no significant correlation between impression cytology and nutritional condition, age time since operation, and percentage weight loss. CONCLUSION These results show impression cytology is a specific indicator for hypovitaminosis A because it is not influenced by other factors related to the general condition of the patient. Many patients with hypovitaminosis A not demonstrating ocular symptoms of changes visible with fluorescein and rose bengal showed alterations with impression cytology.

Echobiometric evaluation of the axial length of the eye and intraocular lens calculation in pseudophakic eyes : Our experience

Intraocular lens (IOL) power calculation in 46 pseudophakic eyes (extracapsular cataract extraction with IOL in posterior chamber), utilizing a Javal keratometer, a Sonomed A 2000 echobiometer (probe 10 MHz, velocity=1,548 m/s) and the SRK2 formula, although there was a statistically significant reduction of the axial length, both in normal and hyperopic eyes, demonstrated no statistically significant differences of IOL power, when compared to the power previously calculated in the phakic eye.

Optimized macular recovery test for the early diagnosis and risk prediction of retinopathy in diabetics

SummaryThe authors present a clinical study on the macular recovery test, in a new optimized version, in normal subjects and in diabetic patients. The discriminating thresholds between normals and retinopathic diabetics and between non-retinopathic and retinopathic diabetics were statistically analyzed.