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Contrast sensitivity was measured in two groups of 20 patients each implanted with refractive and diffractive multifocal intraocular lenses and in two control groups of 20 patients each--the first group implanted with a monofocal IOL and the second phakic subjects. All cases had a postoperative follow-up of at least one year and a corrected visual acuity of 20/20- or better. We used two psychophysical tests, Pelli Robson test chart and Vistech 6500 test chart, and an objective test, visual evoked potentials (VEPs). There were no statistically significant differences in contrast sensitivity in the psychophysical tests between the two groups implanted with multifocal IOLs. The situation was different, however, when they were compared with the control group with monofocal IOLs and the group with phakic eyes: the Pelli-Robson test results were not significantly different, but the Vistech 6500 test showed a significant reduction in contrast sensitivity in both groups. The pattern VEPs objective test confirmed these results: no differences were noted between the two different multifocal IOLs, while there was a drop in contrast sensitivity when their results were compared with those of the control groups; the intermediate frequencies were particularly affected by this phenomenon. The contrast sensitivity in patients with multifocal IOLs is reduced despite high visual acuity and this can affect the quality of vision.

To assess the relationship between pupillary diameter and focusing for distance and near vision with the refractive bifocal intraocular lens (IOL), we studied visual acuity for far and near distance, near point, and depth of focus with normal pupillary movements and after pharmacological miosis and mydriasis (pilocarpine 2% and phenylephrine 10% eyedrops, respectively) in 20 patients implanted with an IOLAB refractive bifocal IOL. Pharmacological miosis and mydriasis did not change far and near visual acuity values from the values with normal pupillary diameter. After pharmacological miosis, the near point position and the width of the depth of focus were unchanged. After pharmacological mydriasis, near point distance was unchanged but depth of focus dropped in a statistically significant manner (P < .01). We concluded that the pupillary diameter alone cannot produce distance or near vision focusing. The choice depends on the brain's preference. Pupillary diameter increases the quality of vision through the blur circles mechanism.

Since some authors have considered useless a differentiation between hemicentral retinal vein occlusion (HCRVO) and hemispheric retinal vein occlusion (HSRVO), we have conducted a prospective research in order to evaluate the clinical and prognostic features of these diseases. We have followed prospectively 26 cases of HCRVO and 25 cases of HSRVO. The most important risk factors were hypertension, diabetes mellitus and glaucoma in HCRVO, and hypertension in HSRVO. In the HCRVO group 20 cases (76.9%) were of the non-ischemic type and six cases (23.1%) were ischemic-type, whereas in the HSRVO seven (28%) were non-ischemic type and 18 cases (72%) were ischemic-type. Our results demonstrate that the two retinal vein occlusions are quite different with regards to pathogenesis, clinical evolution and visual outcome and point out the necessity to achieve a precise diagnosis.

Previous studies have shown the possible development of exudative retinal detachment (ERD) as a complication of retinal vein occlusion (RVO). Considering 473 consecutive cases of RVO, only 3 cases of ERD with peculiar clinical aspects were discovered. In the first case, the ERD followed a branch RVO, but it developed in the opposite quadrant, with a late occurrence of venous retinal collaterals. In the second case, the ERD developed after a central RVO, having a retinoschisis aspect, with the subsequent occurrence of optic disk collateral vessels. In the third case, the ERD was secondary to a hemicentral RVO and involved the entire macular area. The pathogenesis of the ERD subsequent to RVO is still debated. Our experience seems to indicate that the ERD pathogenesis is linked not only to an inability of the draining vascular system, but also to an impairment in the function of the retinal pigment epithelium.

Recent reports have been attempted to evaluate, without obtaining a positive result, whether the reduction in size of the optic disc may influence the pathogenesis of central retinal vein occlusion. Cup/disc ratios in the fellow eye of 67 patients with branch retinal vein occlusion were compared with the ratios of 67 controls matched to cases for age, sex and refractive defect. There was no significant difference between cup/disc ratios of the two groups. These results suggest that the anatomical features of the optic disc are of no importance in the development of branch retinal vein occlusion.

The so-called apparent accommodation has been measured in patients implanted with anterior chamber, iris support and posterior chamber IOLs. The data have been related to pupillary diameter and anterior chamber depth in order to explain the actual possibility of a near vision with optical correction only for distance.

The histopathological features made on 18 autopsies have proved that the optic nerve head drusen are calcified formations situated within the margins of the optic nerve head. It has been supposed that not only an aberrant axoplasmic transport, but also the presence of local factors, partly depending on the Bruch's membrane, can play a determining role in the pathogenesis of the optic disc drusen. A spongiotic edema gives us the histopathological equivalent of the clinical aspect of the optic disc with indistinct margins and lack of the central cup and furthermore gives us an explanation about the perimetric alterations pathogenesis. Clinical observations confirm that the optic nerve head drusen are prevalently asymptomatic and that visual acuity remains unchanged. The threshold tests are able to quantify exactly the entity and the depth of the visual field defects and its possible changing within a certain period of time. As regards the diagnosis, the retinal fluoroangiography is of great importance allowing to distinguish clearly a pseudo-papillary edema from a papillary edema.

On the basis of the assumption of an affinity between cerebral and retinal vessels, it was sought to demonstrate that the variations induced in the retinal circulation are akin to those occurring at the cerebral level. The technique of retinal fluorescein angiography was used to evaluate the amplitude of the vasal lumen and the speed of circulation. In 5 patients, the drug used was (-)eburnamonine. While the calibre of the retinal arterioles did not undergo variations, a shortening of the mean transit time was observed in 3 of the 5 cases treated, evidencing an improvement in blood flow.

A group of diabetic patients was submitted to a capillaroscopic examination at the level of the peri-ungual vallum and to a fluoroangiographic examination of the retina, for the evaluation of possible correlations between vessel conditions in to various districts. The Authors remarked that the subjects affected by proliferative diabetic retinopathy presented a greater dilatation of the ansae at cutaneous level, with haemorrhagic extravasations in 70% of the cases. On the contrary, on the subjects with nonproliferative diabetic retinopathy numerous aneurysmal "buttons" were noted at cutaneous level, both apically and laterally along the vascular ansa.