Francesco Ponte

NEUROCHEMICAL STUDIES ON THE INHERITED RETINAL DEGENERATION OF THE RAT. I. LACTATE DEHYDROGENASE IN THE DEVELOPING RETINA.

Abstract Lactate dehydrogenase activity has been shown to increase in the normal retina and to decrease progressively in the retina of rats with inherited retinal degeneration after the third week of age. In contrast with the quantitative measurements of lactate dehydrogenase in the whole organ, an investigation of the electrophoretic and catalytic features of the enzyme has allowed a very early discrimination between normal and affected rats.

Efficacy of diclofenac eyedrops in preventing postoperative inflammation and long-term cystoid macular edema

Purpose: To compare the efficacy and tolerance of diclofenac 0.1 % eyedrops with a regimen that included a brief course of steroids in the treatment of postoperative inflammation after extracapsular cataract surgery and posterior chamber intraocular lens implantation. A second objective was to compare the efficacy of diclofenac 0.1% eyedrops in the same patients and control group in preventing cystoid macular edema (CME). Setting: Eight university/hospital centers and one company in Italy. Methods: The multicenter, controlled, randomized, prospective, double‐blind study included 281 patients. All were evaluated at baseline, at surgery, and after 1, 5, 36, 67, and 140 days. Postoperative inflammation was measured by the clinical assessment of inflammation: conjunctival hyperemia, ciliary flush, Tyndall effect, and cells in the anterior chamber. Fluorescein angiography was performed to evaluate the presence/absence of CME before surgery and after 36 and 140 days. Results: During follow‐up, no differences in intraoperative pressure were observed within or between groups or between operated and fellow eyes. No statistically significant between‐group differences in postoperative inflammation were found. After 36 days, angiographic CME was found in 9 patients (6.43%) in the diclofenac group and 20 (15.15%) in the control group (P = .033) with a relative risk for developing CME of 0.40 (Cl95 0.19 to 0.84). At the end of follow‐up, it was found in 4 patients in the diclofenac group (3.31%) and 10 (9.26%) in the control group (P = .05) with a relative risk of 0.36 (Cl95 0.12 to 0.90). Conclusion: Diclofenac sodium was as effective as the control regimen in controlling postoperative inflammation after cataract surgery. It also had a protective effect on the development of angiographic CME after 36 and 140 days.

Casteldaccia eye study: prevalence of cataract in the adult and elderly population of a Mediterranean town

Prevalence of cataract was studied in a population based survey performed in adults aged 40 years or more living in Casteldaccia, a small Sicilian town. Lens opacities of moderate or severe grade (type II or worse, according to the Lens Opacity Classification System II) were found at the following rates: nuclear opalescence in 18.5%, cortical cataract in 12.9%, posterior subcapsular cataract in 10.8%. All these types of cataract were much more frequent in the elderly population and were about 1.5 times more common in women than in men. Late cataract was found in about 1/3 of subjects aged 60 to 69 years, in 2/3 of subjects aged 70 or more, but rarely under 60 years of age. However, early cataract was rather common among younger subjects. Cataracts causing a reduction of visual acuity under 0.7 in the worst eye were found in 4%, 8.7% and 21.5% respectively in the three age groups ranging from 40 to 49, 50 to 59 and 60 to 69 years and in 54.4% of subjects 70 years old or over.

Risk factors of ocular hypertension and glaucoma The Casteldaccia Eye Study

A case-control study was planned as a part of the Casteldaccia Eye Study in order to investigate about risk factors of ocular hypertension and glaucoma. Cases were 44 subjects with glaucoma or intraocular pressure of 24 mm Hg or more. Controls were 220 subjects with intraocular pressure of 20 mm Hg or less and no signs of glaucoma. A number of environmental, behavioral, systemic and ocular variables were studied. Among the others we investigated the following: sunlight exposure, smoking, alcohol intake, pregnancies, systemic hypertension, diabetes, use of corticosteroids, refractive status, anterior chamber depth, lens nuclear sclerosis, iris color and texture. After univariate analysis the use of ocular corticosteroids and antibiotics, myopia, shallow anterior chamber and myopic macular degeneration were associated with ocular hypertension or glaucoma. However, the logistic regression showed that only the use of ocular corticosteroids (odds ratio = 7.79) and the myopia (odds ratio = 5.56) were independently associated.

Topical flurbiprofen in extracapsular cataract surgery: Effect on pupillary diameter and iris fluorescein leakage

ABSTRACT Recent clinical studies indicate that flurbiprofen, a cyclooxygenase inhibitor, prevents miosis and breakdown of the blood‐aqueous barrier during cataract surgery. Yet based on clinical and experimental data, some researchers do not agree that flurbiprofen prevents miosis. We conducted a double‐blind clinical study of the effects of topical 0.03% flurbiprofen sodium on intraoperative pupillary diameter and iris fluorescein leakage after extracapsular cataract surgery. In the first phase of the study, 120 patients who had extracapsular cataract extraction with posterior chamber intraocular lens implantation were randomly assigned to receive preoperative topical flurbiprofen or a placebo, with or without intraoperative epinephrine, in addition to the standard regimen. In the second phase, 60 of the 120 patients continued the topical flurbiprofen or placebo for one month postoperatively. Iris fluorescein angiography was performed at the end of the first and the fourth weeks. The results indicate that flurbiprofen was significantly more effective (P < .0001) in maintaining mydriasis during surgery than the placebo. This action was enhanced by intraoperative epinephrine. Flurbiprofen also significantly reduced (P < .001) postoperative iris fluorescein leakage.

Temporal versus superior approach phacoemulsification: Short-term postoperative astigmatism

Purpose: To compare short‐term clinical, postoperative astigmatism, and uncorrected visual acuity results 2 months after no‐stitch phacoemulsification using a temporal clear corneal approach and poly(methyl methacrylate) (PMMA) intraocular lens (IOL) implantation through a 5.2 mm incision with those after no‐stitch superior corneoscleral phacoemulsification. Setting: University Eye Clinic of Palermo, Italy. Methods: This prospective clinical trial comprised 80 patients with senile cataract who were randomly assigned to have phacoemulsification using a temporal approach or a superior approach. Surgically induced astigmatism (SIA) was calculated using Naeser’s polar value method for determining with‐the‐rule (WTR) or against‐the‐rule (ATR) change. Results: There was a highly significant between‐group difference in SIA at each examination (P < .001; t‐test) because of positive (WTR) SIA in the temporal approach group and negative (ATR) SIA in the superior approach group. No other significant differences between groups were found (P < .05, t‐test). More patients in the temporal group had an uncorrected visual acuity of 20/25 or better 2 weeks postoperatively, although the difference between groups was not statistically significant (P = .562; chi‐square). Conclusion: Phacoemulsification using a no‐stitch, temporal, 5.2 mm clear corneal incision produced results comparable to those using a corneoscleral superior approach. A longer study of a larger series should be done to confirm the findings.

Optic pathway conduction in insulin-dependent diabetics

Abnormal latency delay of pattern-reversal visual evoked cortical potentials (VECPs) has been demonstrated in insulin-dependent diabetics without retinopathy as a sign of subclinical damage. Pattern-reversal VECPs and onset-offset (on-off) VECPs probably originated at different cortical levels. On-off latencies of a group of 50 insulin-dependent diabetics without retinopathy or neuropathy and with normal oscillatory potentials have been studied in relation to various clinical and metabolic parameters. The results of our study showed that on-off VECPs have in diabetes the same latency alterations as pattern-reversal VECPs, if to a lesser extent. This finding can be a useful index in the evaluation of patients at risk.

Retinitis pigmentosa and inner retina. Functional study by means of oscillatory potentials of the electroretinogram

The alterations of the inner retina in retinitis pigmentosa have been described in previous papers less often than the external retina alterations, both from the electrophysio-logical and morphological point of view. The oscillatory potentials (OPs) of the electroretinogram (ERG) are a good tool to investigate the inner part of the retina because of the deep anatomical location of their generators. We studied the photopic OPs in a group of 25 subjects affected with retinitis pigmentosa and compared them with other ERG components to obtain information about the functional damage of the inner retina. The OPs were recordable in 9 patients. No analogies were found with the inheritance modes. No relationship was found between OPs and 20 Hz ERG photopic response which was still present in a consistent number of eyes when OPs were no longer recordable. Such finding can be interpreted as an expression of inner retinal damage paralleling the photoreceptors and retinal pigment epithelium impairment.

Surgical therapy for obesity can induce a vitamin A deficiency syndrome

New possible causes and unexplored aspects of the electroretinogram were evaluated in a case of vitamin A deficiency secondary to surgical therapy for morbid obesity. The Naka-Rushton equation, applied to the scotopic b-wave, demonstrated the quantal catch reduction caused by the loss of rhodopsin in the outer segment of photoreceptors. Study of the Fourier analysis of the photopic 20-Hz response suggested a primary involvement of the external retinal layers, with an indirect alteration of the inner layer. The electroretinogram oscillatory potentials showed alterations explained by the involvement of their generators related to the primary photoreceptor lesion.

The role of electroretinography in the diagnosis and prognosis of retinitis pigmentosa.

In 1959, following the clinical examination of two patients with retinitis pigmentosa, we made an interesting electroretinographic observation. In contrast with findings by previous authors, we found that the ERG may be present, although subnormal. A similar result had been reported by several investigators in 21 cases but the significance of the finding was overlooked. The presence of a subnormal ERG in some cases of retinitis pigmentosa puzzled us, in view of the categorical assertion regarding the constant and early disappearance of the ERG in typical forms of retinitis pigmentosa. Our perplexity on this point was still more justified by the fact that in both our cases the presence of a subnormal ERG had been observed even with very low stimuli, at variance with the results by Riggs (1954), Armington and Schwab (1954) and FranGois (1954, 1958). In consideration of this point, we reviewed the diagnostic and prognostic utility of an examination made with high intensity stimuli in all cases of retinitis pigmentosa, since the presence of the ERG would have been observed more often with strong stimuli. The importance of the question we raised was confirmed by the fact that a number of authoritative investigators had been attracted by the observation of this same phenomenon either at the same time or later. Thus, Goodman and Gunkel (1958) illustrated 9 cases of retinitis pigmentosa in two families and described a persistent subnormal ERG. In these cases the disease was inherited as a dominant character. Ruedemann and Noel1 (1959) observed the persistence of a subnormal ERG in 8 out of 38 typical cases of retinitis pigmentosa. They noted that, where