Quantitative photoacoustic spectroscopy of cataractous human lenses.

Quantitative photoacoustic spectra of the nuclei of cataractous human lenses with various degrees of colouration and opacification were measured in the spectral range 250-600 nm. The lens nuclei were obtained from 20 cataractous patients through extracapsular cataract extraction. These measurements yield the light loss per unit path length in the nucleus of cataractous lenses.

Severity of aortic stenosis predicts early post-operative normalization of left atrial size and function detected by myocardial strain.

BACKGROUND: Aortic stenosis (AS) causes significant disturbances in left ventricular (LV) and left atrial (LA) function irrespective of the extent of myocardial hypertrophy which associates the increased afterload. We hypothesize that aortic valve replacement (AVR) and removal of LV outflow tract obstruction should result in LA size and function recovery, even partial, and were set to study this in a group of patients with AVR for AS. METHODS: Peak atrial longitudinal strain (PALS) was evaluated in 43 patients with severe isolated AS and normal EF (56.6 ± 3.8%) and no obstructive coronary artery disease candidates for AVR, pre-operatively and then 40 days and 3 months after surgery. Results were compared with those from 34 age- and gender-matched healthy controls. RESULTS: LVEF remained unchanged and LV mass regressed after AVR. Global PALS was reduced pre-operatively and increased 40 days after surgery (p=0.002) and showed only a slight further increase at 3 months follow-up (p<0.0001). Indexed LA volume was increased before surgery, but significantly fell 40 days after surgery (p<0.0001) and showed only a slight further reduction after 3 months (p<0.0001). Trans-aortic mean gradient change after surgery was the only independent predictor of the recovery of LA size and function. CONCLUSIONS: AVR reverses LA abnormalities and regains normal atrial function, a behavior which is directly related to the severity of pre-operative LV outflow tract obstruction. Early identification of LA size enlargement and functional disturbances might contribute to better patient's recruitment for AVR.

Computer analysis of ENG spectral features from patients with congenital nystagmus.

Power spectral estimation from electromystagmographic recording of eye position is proposed as a simple digital processing method to quantify both the amplitude and the frequency features of eye motion in patients affected by the oculomotor disorder of congenital nystagmus (CN). Different basic wave shapes clinically identified and studied in the literature are shown to have slightly different power spectra, which can be used to characterize the CN disorder from nystagmus waveforms. This treatment, statistical in nature, does not depend strongly on the detailed structure of each recorded wave shape, thus emphasizing that accurate descriptive analysis of all patient's waveforms characteristics adds little to the comprehension of CN. We show that the power spectral estimation also represents a useful tool in modelling both the CN defect and the non-defective oculomotor system, and in assessing the effect of the surgical treatment of CN through the differences in the power spectra before and after surgery.

Spectral analysis of pendular waveforms in congenital nystagmus.

We analyzed quantitatively electronystagmographic recordings of pendular waveforms via spectral analysis methods. We found (1) symmetrical pendular oscillations in orbital positions spanning a range as wide as 40 degrees, with frequencies between 2 and 8 Hz; (2) stable and small pendular oscillations in patients without a null zone and unstable and large pendular oscillations in patients with a neutral zone; (3) a non-decreasing relationship between the amplitude and the frequency of the eye oscillations, and (4) pendular components in orbital positions at the two sides of a neutral zone. It is argued that pendular nystagmus can be generated independently of normal (jerk) nystagmus in the same orbital position.

Posterior chamber intraocular lens implantation in patients with retinitis pigmentosa.

20 eyes of 12 Retinitis Pigmentosa patients underwent extracapsular cataract extraction followed by I.O.L. implantation. No unusual intra or post operative complications were encountered. All pseudophakic eyes showed improvement in visual acuity whereas the V.F. remained unaltered. Subjectively all 12 patients reported a benefit from surgery despite the Visual Field impairment.

Frequency distribution of the time interval between quick phase nystagmic eye movements.

We measured the frequency distribution of the time interval between quick phases of nystagmic eye movements in 8 patients with congenital nystagmus. For each patient we recorded a 3- to 4-second long electro-oculographic (EOG) signal, repeating each session 22 times. The period of the nystagmic cycles was computed for each record, by evaluating the peak frequency of the nystagmic oscillations via spectral analysis of the EOGs. This period is a measure of the time interval between quick phases. Its distribution ranged between 100 and 600 ms and peaked at about 240 +/- 50 ms, with a gaussian shape for values less than about 300 ms. Our measurements were considered as providing the distribution of intersaccadic latencies in normal humans.

Continuous usage of low doses of human leukocyte interferon with contact lenses in herpetic keratoconjunctivitis.

14 patients with primary and recurrent herpetic keratitis were treated with continuous usage of human leukocyte interferon (HLI) at low concentration using therapeutic contact lenses. All patients recovered in a medium-short time of 7 days, including some who had not benefited by previous treatments (idoxuridine, etc.). We conclude that continuous application of HLI increases its effectiveness.

Spectral analysis of dual jerk waveforms in congenital nystagmus.

Congenital nystagmus (CN) is a disorder of the ocular motility characterized by oscillatory eye movements preventing the correct fixation of a target. Many typical waveforms of eye position recordings have been recognized and classified in the literature: in jerk CN a slow phase eye movement is followed by a fast phase, giving rise to a typical saw-tooth waveform, while in pendular CN the eyes exhibit a periodic motion, giving rise to an approximately sinusoidal waveform. Dual jerk waveforms seemed to show small, rapid oscillations superimposed on a jerk-like wave-form, thus being originally classified as a mixture of jerk and pendular CN. On the contrary, a theoretical model of CN has appeared recently, which suggests a possible interpretation of the small amplitude oscillations in dual jerk waveforms as consecutive pieces of growing and decaying exponentials. By spectral analysis of dual jerk waveforms in a number of patients with CN, we show that the oscillations are truly sinusoidal in nature, thus suggesting the possibility of a different explanation of dual jerk waveforms in CN.

On the variations of the time constant of the slow-phase eye movements produced by surgical therapy of congenital nystagmus: a preliminary report.

Quantitative analyses of the effect of nystagmus surgery have been based previously on the pre- and postoperative comparison of the nystagmus intensity at various gaze angles. On the other hand, a recent hypothetical model of the defective oculomotor system producing congenital nystagmus emphasizes that the time constant of the (increasing velocity) slow-phase eye movements should represent a useful parameter in the quantification of the surgical effects, since it is related to the potential good visual acuity of the patients in the presence of nystagmic cycles with extended foveation. By computer analysis of the pre- and postoperative electro-oculographic recordings from 5 patients with congenital nystagmus we show experimentally that the above theoretical indication is a valid tool in the assessment of the effects of classic nystagmus surgery.

Amount of surgery in congenital nystagmus.

By analyzing the clinical data on the amount of surgery on the extraocular muscles and resulting angular shift of the null zone in 24 patients with congenital nystagmus, a linear dependence was found to exist between these two variables. Hence, the amount of surgery can be confidently established in advance of treatment in order to obtain the shift of the null zone. Many cases of partial surgical successes are discussed and explained a posteriori by a lack of a proper amount of surgical rotation.

Rare association of hyperglycinuria and lenticonus in two members of the same family.

2 cases of posterior lenticonus associated with hyperglycinuria without iminoaciduria, found in the same family, were examined. After a review of the literature, the rarity of this association is stressed.

Direct immunofluorescence and scraping conjunctival cytology in the study of 912 patients affected by microfollicular conjunctivitis.

912 patients affected by microfollicular conjunctivitis were submitted to a scraping conjunctival cytology before taking specimens for direct immunofluorescence. 264 patients proved to be positive to the direct immunofluorescence test for Chlamydia trachomatis (CT). In all cases the infection turned out to be bilateral with different degrees of positivity between one eye and the other. In 43 patients out of the 264 positive ones, the cytological examination showed the presence of eosinophils in both eyes. The presence of eosinophils poses the problem of a certain allergizing power of Chlamydia and of the possibility that the CT infection might easily develop in subjects with a preexistent allergic conjunctivitis.

Postsurgical dyskeratosis treated with topical and parenteral administration of vitamin A.

A severe case of conjunctival dyskeratosis was resolved by treatment with high doses of vitamin A administered both topically and parenterally. This result, which was confirmed by cytology, and the lack of adverse effects suggest that vitamin A administration might be a valid alternative to surgery in cases of dyskeratosis.