Low-fluence photodynamic therapy in longstanding chronic central serous chorioretinopathy with foveal and gravitational atrophy

PURPOSE

To describe anatomic and functional outcomes in two patients with long-standing severe chronic central serous chorioretinopathy (CSC) with foveal and gravitational atrophy treated with low-fluence photodynamic therapy (PDT).

METHODS

Two patients with a history of over 10 years of chronic CSC and development of gravitational tracts, with best-corrected visual acuity <or=20/200, were treated with PDT guided by indocyanine green angiography (ICGA) with a fluence of 25 J/cm2 at an irradiance of 300 mW. Follow-up examinations 1 and 9 months after therapy included measurement of near and far best-corrected visual acuity, fundus biomicroscopy, fluorescein angiography and ICGA, optical coherence tomography, and microperimetry.

RESULTS

At 1 and 9 months after low-fluence PDT, complete resolution of subretinal, intraretinal, and under retinal pigment epithelium fluid was observed in both patients. Far and near visual acuity improved in both eyes. Improvement of sensitivity and fixation stability were demonstrated by microperimetry. No treatment-related side effects were seen.

CONCLUSIONS

ICGA-guided low-fluence PDT seems effective and safe for treating long-standing chronic CSC.

Vitreous polyamines spermidine, putrescine, and spermine in human proliferative disorders of the retina

BACKGROUND/AIMS

Many cytokines are involved in the pathogenesis of retinal proliferative diseases, but none has been shown to be related to a specific disorder. The aim of this study was to provide a selective marker of diabetes induced proliferative retinopathies.

METHODS

10 vitreous samples from 10 subjects affected by quiescent proliferative diabetic retinopathy (PDR), 20 vitreous samples from 20 subjects affected by active PDR, and 15 samples from 15 patients with proliferative vitreoretinopathy (PVR) were studied. Samples from 18 patients with a macular hole (n = 8) or pucker (n = 10) served as controls. Vitreous samples were obtained via pars plana vitrectomy. The polyamines spermidine, putrescine, and spermine, vascular endothelial growth factor (VEGF), interleukin 8 (IL-8), and transforming growth factor 1beta (TGF-1beta) were measured by high performance liquid chromatography (HPLC) and enzyme linked immunosorbent assay (ELISA), and the correlation coefficients between the vitreous polyamine content and VEGF, IL-8, and TGF-1beta levels were determined.

RESULTS

Spermidine and putrescine were expressed in normal vitreous, but spermine was not detectable. In all the test groups spermidine was 3-4 times higher than in control vitreous and putrescine was similarly lower. The spermine content was up to 15 times higher only in vitreous from patients affected by PDR. Correlation coefficients showed that the spermidine and putrescine level variations correlated with the VEGF and IL-8 content in the active PDR and PVR groups, but not in those with quiescent PDR patients, while spermine was correlated to these cytokines in PDR, but not in PVR groups.

CONCLUSIONS

These data suggest a significant role for spermidine and putrescine as markers of proliferative diseases of the retina. The increase in spermine, restricted to diabetic states, may indicate that this polyamine is a unique and specific index of PDR.

Diabetic patients and retinal proliferation: an evaluation of the role of vascular endothelial growth factor (VEGF)

Vascular endothelial growth factor (VEGF) has been shown to play a major role in intraocular neovascularisation in ischaemic retinal diseases. The aim of this study was to evaluate the concentration of VEGF in vitreous, aqueous and epiretinal membranes of diabetic and non-diabetic patients, with other pathological conditions requiring surgical intervention. Higher VEGF concentration were found in samples from the eyes of diabetic patients versus other pathologies as well as in epiretinal membranes versus the other eye compartments in diabetic patients. However, high VEGF levels were also found in retinal detachment and proliferative vitreoretinopathy of non-diabetic patients. We concluded that VEGF is produced locally and plays a fundamental, but not specific, role in diabetic retinal neovascularisation and proliferation.

Biocompatibility and biodegradation of intravitreal hyaluronan implants in rabbits

To study the biocompatibility and the biodegradation rate in vivo of new intravitreal implants made with three different hyaluronic acid esters: Hyaff7, Hyaff11 and Hyaff11p75 (100% ethyl ester, 100 and 75% benzyl esters, respectively), the plugs were implanted through a sclerotomy at 3.5 mm from the limbus of rabbit eyes. In order to evaluate the in vivo biodegradation the shaft diameter of the plugs was measured by ultrasound biomicroscopy. Slit lamp microscopy, ophthalmoscopy and ERG were performed periodically. The effects of the implants on ocular tissues were also evaluated histologically. All the plugs showed a good biocompatibilitv. Plugs of both the total esters, Hyaff7 and Hyaff11, were found to undergo a slow dissolution process for 60 and 150 days, respectively. The partial benzyl ester, Hyaff11p75, was completely reabsorbed after 15 days. Analysis of variance showed a high correlation between biodegradation rate and the time of resorption (F = 90.5; p < 0.001). The biodegradation rate of each implant is related to the chemical structure of the three types of Hyaff (F = 4.51; p = 0.005). The present data suggest that intravitreal implants based on hyaluronic acid esters represent useful biocompatible and biodegradable devices for a potential drug delivery system in the treatment of posterior segment ocular diseases.

Corneal oedemas: diagnosis and surgical planning with ultrasound biomicroscopy

We used the Humphrey Ultrasound Biomicroscope (UBM System 840 by Zeiss-Humprey Instruments, San Leandro, Calif. USA) to study various corneal oedemas and leucomas. This UBM system, using a high-resolution probe of 50 Mhz, has an axial and lateral resolution of about 50 micrometer. We analysed 36 eyes divided into two groups, 27 (group A) affected by corneal oedema caused by traumatic-mechanic or phlogistic-toxic lesions, 9 (group B) affected by postsurgery oedema. Thanks to its high-resolution power, we could study their pathogenesis and their clinical evolution and so arrange a suitable therapy and perform an accurate follow-up of these pathologies.

Keratoconus staging with ultrasound biomicroscopy

The diagnosis of keratoconus is based on slip-lamp and keratometric findings, and its classification includes 4 different stages. In this study, we compare the ultrasound biomicroscopy (UBM) findings and the keratoconus index (KI) determined using UBM with the severity of the disease. By means of UBM (Humphrey Instruments system model 840) using a 50-MHz probe, we studied 49 eyes affected with different forms of keratoconus. Using a method previously described, we calculated the KI and compared these data with the findings obtained using videokeratography. The mean thickness at the corneal apex in keratoconic eyes was 0.369 mm, while the mean peripheral corneal thickness was 0.568 mm. The mean KI was 1.449 in keratoconic eyes. The KI increased according to the severity of the disease. The mean central keratometry power was 56.95, while the mean amount of steepening of the inferior cornea compared with that of the superior cornea was 8.16. UBM can be considered a useful tool in the study of keratoconus. Using high-frequency ultrasound, it is also possible to obtain reliable measurements of corneal thickness related to the severity of the disease determined by videokeratography.

Ultrasound-biomicroscopic evaluation of filtering blebs after laser suture lysis trabeculectomy

Sometimes in glaucomatous patients treated with trabeculectomy there is no correlation between bleb shape and intra-ocular pressure (IOP). In this study we evaluated the ultrasound biomicroscopy (UBM) features of filtering blebs after laser suture lysis (LSL) trabeculectomy in order to analyse whether its ultrasound-biomicroscopic image can predict the function (IOP).

METHODS

The Humphrey ultrasound biomicroscope, using a high-frequency (50-Mhz) probe, provides high-resolution images of filtering blebs. A total of 103 filtering blebs after LSL trabeculectomy were analysed by UBM. Taking into account the characteristics of internal reflectivity and scleral flap, we classified the blebs into three groups (good, fair, poor) that indicate the bleb function and correlated this UBM pattern with the IOP control (good, borderline, failure).

RESULTS

There was a statistically significant corelation between the UBM classification of function and the IOP control level. Both well-functioning and failed trabeculectomies could be identified by UBM. The UBM images of eyes with good IOP control are characterized by better visibility of the route under the scleral flap and a low reflectivity inside the bleb.

CONCLUSIONS

In accordance with previous studies, we believe that UBM can be a useful method to study and explain the mechanisms of filtering structures and, together with IOP control, to evaluate the bleb function.

Long-term visual results of bifocal intraocular lens implantation

PURPOSE

To evaluate the long-term visual results and variability in contrast sensitivity in patients with heparin-surface-modified (HSM) diffractive bifocal intraocular lenses (IOLs).

SETTING

Institute of Ophthalmology, University of Catania, Italy.

METHODS

In this prospective study, visual acuity (distance and near) and contrast sensitivity were measured in 35 patients who had phacoemulsification with bifocal diffractive IOL (model 811E, Pharmacia) implantation. Patient satisfaction was also evaluated using a questionnaire. Mean follow-up was 20 months (range 18 to 24 months).

RESULTS

At the last examination, mean distance visual acuity was 0.79 +/- 0.2 (SD) without correction and 1.0 +/- 0.15 with best correction. Mean uncorrected near visual acuity was J1.6 +/- J0.77 and with best distance correction, J1.19 +/- J0.49. No statistically significant changes in visual acuity were evident at the last follow-up (Student t test). No changes were found in contrast sensitivity reduction over time, nor were late postoperative complications noted. Overall patient satisfaction was rated as good by 94.3% of patients with best distance correction.

CONCLUSIONS

The diffractive bifocal HSM IOL provided good visual performance for distance and near over time. In relation to the low rate of postoperative complications, the slight contrast sensitivity reduction was stable during follow-up.

[Evaluation of the filtering bleb using ultrasound biomicroscopy]

BACKGROUND

Sometimes in glaucomatous patients treated with trabeculectomy there is not a correlation between bleb shape and intraocular pressure. So we studied the functional anatomy of the filtering bleb by a ultrasound biomicroscope, using high frequency (50 Mhz) probe, which provides high resolution images of filtering blebs.

MATERIALS AND METHODS

A total of 46 filtering blebs of 46 patients after trabeculectomy were analyzed by ultrasound biomicroscopy (50 Mhz). Dimensions, shapes and structure of blebs were evaluated in 2 groups of patients.

RESULTS

It was possible to obtain longitudinal or transverse images of filtering blebs, to measure the height, to evaluate the reflectivity inside and to follow the route under the scleral flap. Blebs with lower reflectivity and a visible route under the scleral flap had a lower intraocular pressure while the height was not important for a good intraocular pressure.

CONCLUSIONS

So ultrasound biomicroscopy can be a useful method to study filtering blebs and also to explain the mechanisms of filtering structures in patients who underwent trabeculectomy.

[Incidence of ROP (Retinopathy of Prematurity) in hypoxemic neonates: case contribution]

In this retrospective study the Authors correlated the hypoxia with the severity of retinopathy of prematurity (ROP) in a population of 683 outborn preterm infants (bw < 2500 g and gestational age < 38 weeks). They excluded all cases with specific pathological conditions. Among neonates with the same gestational age the incidence of ROP was higher (p < .05) in those with hypoxia (pH < 7.25, tcPO2 < 50 mmHg). These data suggest that hypoxia plays a role in the pathogenesis of ROP.

Evaluation of central and peripheral corneal thickness with ultrasound biomicroscopy in normal and keratoconic eyes

PURPOSE

Our study was designed to calculate central and peripheral corneal thickness in patients affected with early stages of keratoconus and in normal subjects using ultrasound biomicroscopy (UBM). To obtain an objective and reliable assessment of the corneal thinning in affected eyes, we developed a keratoconus index (KI) by means of the UBM measurements.

METHODS

By means of the commercial version of the ultrasound biomicroscope (system model 840; Zeiss-Humphrey Instruments, San Leandro, CA, USA) using a 50-MHz probe, we studied 30 normal and affected eyes. In keratoconic eyes, we measured the thinnest corneal thickness (TCT) at the apex of the conus and at four peripheral sites at a distance of 2.5 mm from the central site (peripheral corneal thickness: PCT). The same procedure was performed in the normal eyes. To obtain an objective and reliable assessment of the corneal thinning, we calculated the ratio between the mean PCT and the mean TCT (Keratoconus Index: KI = PCT/TCT), in keratoconic eyes. In normal eyes, the KI was calculated on the basis of the ratio between the mean PCT and the mean central corneal thickness (CCT).

RESULTS

In keratoconic eyes, the mean corneal thickness at the thinnest part of the conus was significantly different from the CCT in normal patients (Student's t test, p < 0.001). The peripheral measurements were not significantly different from keratoconic and normal eyes. The mean KI was 1.482 (SD, 0.095) in the keratoconic eyes, whereas it was 1.189 (SD, 0.086) in the normal subjects. The statistical analysis of the KI calculated on the basis of the UBM measurements showed that the KI values are significantly different from healthy subjects and from keratoconic patients (Student's t test, p < 0.001).

CONCLUSIONS

UBM can be considered a useful tool in the study of keratoconus. We believe that calculation of the KI by means of UBM gives the possibility of obtaining an objective assessment of corneal thinning. Therefore this parameter can be useful in the staging and in the follow-up of these patients.

[Controlled trabeculectomy and incidence of postoperative choroidal detachment]

In this study the authors report their experience with titrated trabeculectomy. It is performed as follows: tight scleral flap trabeculectomy, five or more 10/0 nylon sutures, argon laser lysis of one or more sutures (depending on the eye's postoperative condition) by means of the Hoskins lens. The aim of this technique, performed by the authors for 3 years, is to decrease atalamia and choroidal detachment. Results obtained in 70 eyes of 62 patients with chronic open-angle glaucoma are compared by means of statistical analysis with those in 70 eyes of 66 patients operated on by means of the traditional technique. The incidence of choroidal detachment is significantly reduced (P < 0.001). There is no important difference in ocular pressure and visual acuity. In conclusion, this technique is very useful in controlling and titrating the filtration rate, avoiding an excessive lowering of IOP after trabeculectomy and decreasing the complications.

[Experiences with sclerostomy with the Holmium laser]

The THC-YAG laser (holmium laser) war used to perform ab externo sclerostomies in patients affected by various types of glaucoma. This approach was employed in 48 eyes with diagnoses of medically uncontrolled chronic open angle glaucoma, plateau iris or neovascular glaucoma. Post-operatively, 5-FU was injected. At the tend of the follow-up (mean 10.22 +/- 3.4 months), in 25 eyes (52.1%) the IOP was under control without medical therapy. In 12 eyes (25.0%) it was necessary to use antiglaucomatous topical therapy, and in 11 eyes (22.9%) the IOP was uncontrolled despite therapy. The authors stress the importance of a correct pharmacological protocol before and after operation and describe the surgical technique. They confirm the validity of this approach, owing to its minical invasiveness, the possibility of repeating the procedure, and the low complication rate.

[Determination of contrast sensitivity in patients with silicone oil tamponade]

The issue of whether silicone oil has a toxic effect on the retina is still being debated. In order to verify possible retinotoxic effects, the authors studied the variations of retinal function by means of computerized perimetry on patients who had undergone a vitreoretinal operation with injection of silicone oil in the vitreous cavity. Silicone oil remained in the eyes for a period of 120 days +/- 15.

PATIENTS AND METHODS

14 patients under treatment for vitreoretinal pathologies sparing the macula underwent five examinations (Macular Threshold Test of the Humphrey Field analyzer): two examination during the period silicone oil was in the vitreous cavity (30 days after injection and 10 days before removal) and three examinations after its removal (at 30, 90, and 180 days).

RESULTS

When the paired t-test and ANOVA test were applied to our results, there were no significant differences in the light-difference sensitivity.

CONCLUSIONS

These data do not indicate that silicone oil a retinotoxic effect (revealed by means of computerized perimetry) when it is removed within 4 months.

[Epidemiological,and physiopathological findings in retinopathy of prematurity: the authors' personal cases]

The authors present a retrospective epidemiological study on retinopathy of prematurity (ROP), performed on 738 newborns with a gestational age of 34 +/- 2.41 weeks and birth weight of 1971 +/- 351 g. They excluded all cases with severe respiratory distress and other pathological conditions. First stage of ROP shows no correlation with gestational age and birth weight, whereas second and third stages of ROP show an inverse correlation with the above mentioned factors, particularly birth weight. Among neonates with the same gestational age, the incidence of ROP is higher in those "small for date". Regarding the pathogenesis of ROP, the authors outline the importance of perinatal hypoxia.

MRI and intraocular tamponade media

Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, fluorosilicone oil, or perfluorocarbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment.

Surgical management of closed angle glaucoma: our experience

In this paper we present our experience of the last three years in the surgical treatment of eyes with closed angle glaucoma. We have performed an extracapsular lens extraction and posterior chamber intraocular lens implantation on 34 eyes of 34 patients. All of them were affected by closed angle glaucoma with variable control after a Yag laser iridotomy: 6 eyes had high I.O.P. notwithstanding maximal therapy, 11 eyes had I.O.P. under control (less than 21 mmHg) without therapy, 9 with I.O.P. controlled with topical therapy, 8 with I.O.P. controlled with maximal therapy (C.A.I. included). The cases with well controlled glaucoma were operated on because of the presence of a more or less significant lens opacities. After a follow-up of up to 40 months (mean = 20.3, range = 1-40), all eyes show satisfactory intraocular pressure and no eye needed a filtering procedure. The results of our studies are as follows (values are mean +/- SD). In the group of 6 eyes with high I.O.P., the mean pre-operative intraocular pressure was 29.7 +/- 5.6 mmHg and the mean post-operative I.O.P. was 15.1 +/- 1.4 mmHg. The mean reduction was 14.5 +/- 6.6 mmHg (p < 0.005). In the 28 eyes with pre-operative I.O.P. under control (17.5 +/- 1.6), the mean post-operative I.O.P. was 14.4 +/- 2.3 mmHg, with a mean reduction of 3.1 +/- 3.1 mmHg (p < 0.005). Before the E.C.C.E., 11 eyes had I.O.P. less than 21 mmHg without anti-glaucoma medication, whereas after the E.C.C.E. 28 eyes did not need such a medication.(ABSTRACT TRUNCATED AT 250 WORDS)

[A new surgical procedure in angle block glaucoma]

Authors show the results obtained in 29 eyes of 29 patients with closed angle glaucoma operated with ECCE plus posterior chamber IOL implantation. After a follow up varying from 1 to 35 months (mean = 20.7) all eyes are under good control (25 without therapy, 4 with topical therapy) of I.O.P. Authors report on the "rationale" of their surgical approach: particular anatomo-functional features of the eyes affected by closed angle glaucoma. Pre-op. and post-op. biometrical and gonioscopical findings are described and discussed.

Effects of hyaluronic acid fractions in the rabbit eye

Two fractions of hyaluronic acid with different molecular weight (Ial, molecular weight 500,000-730,000 and Healon, molecular weight 750,000) were injected intracamerally or intravitreously in the rabbit eye. Although the fraction with higher molecular weight caused an increase in intraocular pressure, no change of this parameter was found after administration of the fraction with the lower molecular weight. Furthermore, various inflammatory reactions in ocular tissues were observed during slit-lamp biomicroscopy after administration of Healon but not of Ial. No inflammatory reaction was found after subchronic instillation of the compounds.

Fifteen years of experience in retinal surgery

We report our experiences with retinal surgery. The importance of vitrectomy and the use of silicone oil are mentioned although the latter can be responsible for iatrogenic proliferative vitreoretinopathy.

Retinopathy of prematurity (ROP): optimal timing of clinical evaluation and standard procedures

The authors present the protocol currently used in their institution for initial and follow-up evaluation of infants at high risk for developing retinopathy of prematurity (ROP). After topical anesthesia and lid speculum insertion, the examination is carried out using an indirect binocular ophthalmoscope with a +20 or +28-diopter lens. Mydriasis is achieved by instilling one drop of 1% tropicamide, followed by one drop of 0.5% tropicamide + 2.5% phenylephrine 15 minutes later and after an additional 15 minute interval, another drop of 1% tropicamide. If mydriasis is insufficient after one hour, one drop of a 0.5% tropicamide-5.0% phenylephrine solution may be instilled. The initial examination is performed between the third and fourth weeks of life. If any areas of retinal immaturity are found, the examination is repeated every other week and, later, every three to four weeks, until vascularization has reached the ora serrata. Should any sign of ROP be present during the first examination, the patient is examined weekly or every other week depending on the severity of clinical findings.

Effects of dapiprazole on contractile responses of guinea pig isolated ileum

The effects of dapiprazole, a relatively new alpha 1-adrenolytic agent, on contractile responses and on spontaneous mechanical activity were studied in guinea pig isolated ileum. Dapiprazole (10(-10) to 10(-4) M) produced a concentration-dependent inhibition of high K+ (80 mM) -induced contractions. These inhibitory effects were observed with dapiprazole added either before or after the induced contractions. The Ca2+-induced contractions of K+-depolarized ileum were also inhibited by dapiprazole. Dapiprazole inhibited in a non competitive manner the responses of the ileum to: carbachol, histamine, 5-hydroxytryptamine, pentagastrin, angiotensin II and cholecystokinin. In order to analize whether dapiprazole exerts an intracellular effect on Ca2+-store, skinned preparations were used. The results suggest that dapiprazole might inhibit Ca2+ entry through both voltage-and receptor-operated channels of the smooth muscle membrane.

Receptor-responses in fresh human ciliary muscle

The physiological and pharmacological properties of ciliary muscle isolated from fresh human eyes were investigated. The muscle exhibited no spontaneous activity. Concentration-dependent contractions in response to carbachol were competitively antagonized by atropine (pA2 = 8.95). The muscle, precontracted by carbachol (2.7 X 10(-4)M), responded to the application of isoprenaline by concentration-dependent relaxation blocked by propranolol (3.5 X 10(-9)M to 3.5 X 10(-8)M; pA2 = 9.15). Angiotensin-evoked contractions were antagonized by 8-Ala-angiotensin II (4.5 X 10(-8)M) in a competitive manner, but were not inhibited by phentolamine or propranolol. Contractions generated by electrical stimulation of the muscle (30 ms, 20 Hz, 60 pulses) were antagonized by atropine (10(-7) M) and tetrodotoxin (6.3 X 10(-7) M). Phentolamine and propranolol did not influence these responses. An increase of the external potassium concentration ([K+]o) from 5.4 to 158.8 mM produced a mechanical response, antagonized by atropine, but not influenced by tetrodotoxin, phentolamine or propranolol. The human ciliary muscle appears to carry muscarinic and angiotensin receptors and beta 2-adrenoceptors. The estimate of Katropine for muscarinic receptors mediating carbachol-induced contractions agrees with estimates of Katropine reported for human and rabbit iris.

Laser and glaucoma: our experience

The authors present some guidelines on laser therapy (Argon and/or Yag) application on the different types of glaucomatous pathology. These therapeutic guidelines are the result of a 3-year experience of constant laser therapy application on glaucoma. The case reports include 196 A-laser trabeculoplasties, 34 A-laser iridotomies, 158 Yag-laser iridotomies, 31 gonioplasties, plus numberless combined treatments (iridotomy-trabeculoplasty, gonio-trabeculoplasty, gonioplasty-ciliary body photocoagulation, and so on). The authors conclude by reaffirming the considerable reliability of these techniques, given a prolonged follow-up; they also advance some new therapeutic hypotheses on laser operation in glaucomas.

Iris receptors of fresh human eyes

There are many reports describing the receptorial distribution in animal eyes but only a few reports concerned with human eyes. Because of this, we have studied five fresh human eyes, in vitro, by a very sensitive method. We have proved the existence of alpha exciting and beta 2 relaxing receptors on the iridial dilatator muscle and the absence of cholinergic, serotoninergic, dopaminergic, histaminergic receptors. On the contrary, on the circular muscle we have found muscarin cholinergic receptors without adrenergic ones.

[Preliminary study of the topical use of thymoxamine]

In this work the Authors have tried to show the efficacy of TMX, as a miotic drug, and to find out the lowest concentration which can give the best results with the minor complications. Seven patients, in whom TMX was instilled in both eyes at 0.50%, 1%, 2% concentrations, were studied. A mydriatic was instilled before in the right eye, in order to obtain mydriasis whereas the left eye served as control. The 0.5% concentration was as efficacious as 1% and 2% ones, but had less side-effects.

[The effect of antiglaucoma drugs on the depth of the anterior chamber (I)]

The Authors have taken into account the most common effect of antiglaucomatous drugs on the depth of the anterior chamber. The modifications of the anterior chamber have been evaluated utilizing a Jaeger Pachymeter. The values were obtained before the drug instillation and an hour afterwards. The results are presented as the mean and standard deviation. Among the examined drugs, only miotics have brought about a notable decrease, whereas the others have shown no significant effects.

[Histopathological observations of the human retina treated with argon-laser]

The Authors were able to observe histologically the lesions induced by Argon-laser on the retina and choroid of two eyeballs that afterwards were enucleated because they developed choroid melanoma. The observations have been respectively made 10, 20 and 40 days after the beginning of the treatment and a progressive structural overturning of the retina and the choroid due to the obstruction of choriocapillary vessels, to the tendency to fusion of the various nuclear layers as well as to the connection of the layer of nerve fibres, has been observed.

[Preliminary study of acidification of the pH of the aqueous humor in rats treated with timolol maleate]

The Authors have studied in a homogeneous group of rabbits the variations of intraocular pressure and of aqueous humour pH caused by instillation of timolol maleate at different concentrations. In the animals treated with drug concentration of 0,25% and 0,5% a constant reduction of IOP has been observed in comparison with controls, associated to acidification of aqueous humour: no evidence of this correlation it seems to be at low doses of timolol. Further studies are in course to indicate an eventual action of intermediate substances in the mechanism of IOP depression caused by timolol.

[Prevention of retinal detachment in massive endovitreous hemorrhage 1a]

We have made a prophylaxis of retinal detachment resulting from massive endovitreous hemorrage by applying a silicone encirclement on rabbit eyeballs in which we have previously injected autologous blood. Because of the opacity of the means echography has shown us the moment of intervening. Retinal detachment has taken place in the 64,28% of cases, against the 91,3% of a previous experience of ours in which we made no prophylactic.

[Prevention of retinal detachment in massive endovitreous hamorrhage. 2a]

We have made a prophylaxis of retinal detachment resulting from massive endovitreous hemorrhage by performing a pars plana vitrectomy in rabbit eyeballs, in which we had previously injected autologous blood. Because of the opacity of the means the echografic examination has shown us the moment of intervening. The detachment of retina has taken place in the 46,15% of case, wherease in some of our previous experiences it has happened in the 91,3% without the prophylactic intervention and in the 64,28% after application of encirclement.

[Prevention of retinal detachment in massive endovitreous hemorrhage. 3a]

We have made a prophylaxis of retinal detachment resulting from massive endovitreous hemorrhage by associating a pars plan vitrectomy and an application of encirclement in rabbit eyeballs, in which we had previously injected autologous blood. Because of the opacity of the means, echography has shown us the moment of internention. The retinal detachment has taken place in yhe 20,83% of cases whereas in our previous experience it had happened in the 91,3% without prophylactic intervention, in the 64.28% after application of encirclement and in the 46.15% after vitrectomy.

[Central serous retinopathy. Etiopathogenetic and clinical considerations (author's transl)]

Etiopathogenetic, clinical and therapeutic study of 24 patients affected with central serous retinopathy, hospitalized in the Ophthalmological Clinic of the University of Bari during the period 1977-1978. After reviewing the main pathogenetic theories on the disease and taking into consideration their own findings, which are also based on specific psychiatric tests, the authors conclude that central serous retinopathy probably has a psychoangiospastic etiopathogenesis.