Enrique España

Visual performance with multifocal intraocular lenses: mesopic contrast sensitivity under distance and near conditions.

OBJECTIVE To evaluate distance and near visual performance under bright (photopic) and dim (mesopic) conditions in patients who had undergone uncomplicated cataract extraction with multifocal or monofocal intraocular lens (IOL) implantation. DESIGN Prospective, nonrandomized, masked, comparative, observational case series. PARTICIPANTS Thirty-two eyes of 32 patients after zonal-progressive multifocal IOL implantation (Allergan Medical Optics Array SA-40N) and 32 eyes of 32 age-matched patients after monofocal IOL implantation (Allergan Medical Optics SI-40NB). INTERVENTION All eyes underwent phacoemulsification and IOL implantation. MAIN OUTCOME MEASURES At 18 months after surgery, the monocular contrast sensitivity (CS) function was measured with sinusoidal grating charts at distance and near, at one photopic luminance level and 2 mesopic luminance levels (85, 5, and 2.5 candelas per square meter). RESULTS Under bright conditions, CS at distance in the multifocal group was not statistically different (P>0.01) from that in the monofocal group at any tested grating spatial frequency (1.5, 3, 6, 12, and 18 cycles per degree [cpd]). At low luminances, distance CS for the multifocal group was worse than that for the monofocal group at the highest test spatial frequencies (12 and 18 cpd; P<0.01). At near, photopic CS in the multifocal group was lower than at distance; patients with only a monofocal distance correction, however, could not detect the test gratings, even at the highest available contrast. With optimal near spectacle additions (i.e., using the distance correction of the multifocal IOL), there were no significant differences between the photopic near CS values for the multifocal and monofocal groups. When the luminance was decreased, near CS at all spatial frequencies was reduced in both groups. Contrast sensitivity in the near-corrected, multifocal group was significantly worse than in the near-corrected, monofocal group at high spatial frequencies (12 and 18 cpd). CONCLUSIONS This work supports the findings of earlier authors that the Array multifocal IOL, with its center-distance design, is distance biased. Distance CS is within normal limits under bright photopic conditions but shows deficits at higher spatial frequencies (more than approximately 12 cpd) under dim mesopic conditions. Near CS obtained with the multifocal IOL is below that which can be achieved by an appropriate monofocal near correction, for all spatial frequencies and illumination conditions.

High dose intravitreal foscarnet in the treatment of cytomegalovirus retinitis in AIDS.

The efficacy and tolerance of high dose intravitreal foscarnet for cytomegalovirus retinitis in patients with AIDS was studied. Foscarnet in a dose of 2400 micrograms was injected directly into the vitreous of 11 patients (15 eyes). Five patients had active retinitis (eight eyes, 53.3%), and received a 3 week induction therapy of six injections as the first step. Six patients had initial inactive retinitis (seven eyes, 46.7%), and received only maintenance therapy which consisted of a weekly injection. The main indications for intravitreal therapy were: myelosuppression, kidney toxicity, catheter related sepsis, or refusal of intravenous therapy. The patients were followed for a mean period of 16 weeks (range 8-28 weeks) and received a total of 304 injections. Vitreous foscarnet levels were measured by high performance liquid chromatography. After a 3 week course of induction therapy, complete resolution of the active retinitis was seen in 62.5% (5/8 cases), while 37.5% (3/8 cases) had partial resolution. No cases failed to respond or progress. The rate of relapse on maintenance therapy was 33% (five of 15 eyes) by 20 weeks, and two of these eyes did not respond to reinduction and progressed in involvement of the macula or optic nerve. Neither important local complications nor intraocular drug toxicity were observed. Vitreous foscarnet levels in two different patients were 896 mumol/l and 74.9 mumol/l at 22 3/4 hours and 42 1/2 hours after the injection. Intravitreal foscarnet appears to be a safe, effective, and useful alternative in patients with intolerance to intravenous and viral therapy.

Low-spin six-co-ordinate cobalt(II) complexes. A solution study of tris(violurato)cobaltate(II) ions

The formation of complexes of CoII with violuric acid (1H,3H-pyrimidine-2,4,5,6-tetrone 5-oxime), H3vi, and its monomethyl (H2mvi) and dimethyl (Hdmvi) derivatives in dimethyl sulphoxide–water (80 : 20) has been investigated. Potentiometric, calorimetric, magnetic, and e.s.r. measurements clearly evidence that [Co(H2vi)3]–, [Co(Hmvi)3]–, and [Co(dmvi)3]– are low-spin octahedral complexes. The high spin–low spin change occurs upon binding of the third ligand.

Intravitreal Foscarnet for Cytomegalovirus Retinitis in a Patient With Acquired Immunodeficiency Syndrome

We treated a patient who had acquired immunodeficiency syndrome and cytomegalovirus retinitis of the left eye. After anesthetic had been topically administered, the patient received intravitreal injections of 1,200 micrograms of foscarnet. Plasma and vitreous foscarnet levels were measured by high-performance liquid chromatography. Systemic absorption of the drug was not evident. Elimination half-life from the vitreous after one injection was 54.0 hours. Vitreous levels remained above the mean 50% inhibition value for cytomegalovirus for approximately 56 hours and above the mean inhibition value for human immunodeficiency virus for approximately 241 hours. The patients visual acuity improved from 20/30 to 20/25 in the left eye. Ophthalmoscopy showed the retinal lesion to have become inactive, and no reactivation occurred during the follow-up period of more than four months. The drug was well tolerated and no retinal toxicity was evident. We suggest an induction treatment regimen of two injections weekly for three weeks, followed by a maintenance treatment regimen of one injection weekly.

Mesopic contrast sensitivity function after laser in situ keratomileusis.

PURPOSE To evaluate contrast sensitivity under mesopic conditions in patients who have undergone uncomplicated bilateral laser in situ keratomileusis (LASIK) for myopia. METHODS Best-corrected monocular contrast sensitivity was measured with the Stereo Optical F.A.C.T. chart at 1.5, 3, 6, 12, and 18 c/deg in 20 patients (20 left eyes) before and after bilateral LASIK (with the Nidek EC-5000 excimer laser and the Automated Corneal Shaper). Mean preoperative refractive error was -6.40 +/- 1.28 D (range -4.00 to -8.00 D) and postoperative mean refractive error was -0.41 +/- 0.45 D (range -0.75 to +0.50 D). Contrast sensitivity function was measured before and 6 months after surgery using four different chart luminances: 85, 5, 2.5, and 0.1 cd/m2, the first being a photopic level and the rest mesopic. Log contrast sensitivity values at each spatial frequency were used for statistical analysis and normalized values for graphical representation. RESULTS Contrast sensitivity of postoperative LASIK eyes did not differ from preoperative values at a photopic level (85 cd/m2). However, under mesopic conditions (5 cd/m2 or less) a statistically significant reduction (P<.01) in contrast sensitivity was found at high spatial frequencies (12 and 18 c/deg), although no significant contrast sensitivity differences were observed at low and middle spatial frequencies (P>.01 for 1.5, 3 and 6 c/deg). CONCLUSIONS LASIK induced significant reductions in contrast sensitivity under mesopic conditions only at high spatial frequencies, even though the photopic contrast sensitivity function was normal.

Liposomally-entrapped ganciclovir for the treatment of cytomegalovirus retinitis in AIDS patients

Treatment of retinitis by cytomegalovirus (CMV) in AIDS patients requires frequent repetitive injections of intravitreal ganciclovir (GCV). This study was undertaken to establish experimentally whether the intravitreal application of liposomally-entrapped GCV could prolong intraocular therapeutic levels when compared with the intravitreal injection of free GCV, and the clinical effectiveness of this approach in AIDS patients. Intraocular concentration of GCV was determined by means of an ELISA test in rabbit vitreous 2, 3, 7, and 14 days after a single intravitreal injection of either different doses of the free drug (0.2–20 mg) or 1 mg of liposomally-entrapped GCV. After 72 h, only the vitreous of rabbits injected with doses of free GCV greater than or equal to 5 mg showed therapeutic levels of the drug; no GCV was detected after 72 h with any of the doses applied. Moreover, the microscopic study revealed GCV-induced damage in retinal structures in the animals injected with a free GCV dose greater than or equal to 15 mg. Intravitreal injection to rabbits of 1 mg of liposomally-encapsulated GCV showed no retinal toxicity at any of the time points studied, and therapeutic levels were detected up to 14 days after injection (4.67 ± 0.39 μg/ml). Five AIDS patients suffering CMV retinitis were injected with 0.5 mg of liposomally-entrapped GCV (2 mg of lecithin). Complete remission of the CMV retinitis was observed already at the third injection of 0.5 mg GCV (one per week) and relapse did not occur during the 2–4 month follow-up of the patients. In view of the results presented, it can be concluded that intravitreal injection of liposomally-encapsulated GCV increases the time period required for reinjections in the treatemnt of CMV retinitis.

Síndrome de Susac de presentación ocular atípica

espanolCaso clinico: Mujer de 25 anos de edad afecta de encefalopatia y perdida auditiva neurosensorial, remitida a nuestro servicio para confirmar un sindrome de Susac por presentar una disminucion de agudeza visual bilateral. En la exploracion funduscopica se aprecio una microangiopatia retiniana periferica. Discusion: El sindrome de Susac se caracteriza tipicamente por la triada encefalopatia, perdida auditiva neurosensorial, y oclusiones de ramas arteriales retinianas. En nuestro caso las alteraciones oculares eran atipicas, apreciandose amputacion de vasos terminales con cumulo de microaneurismas en retina periferica de ambos ojos. EnglishCase report: A 25-year-old woman with encephalopathy and sensorineural hearing loss was referred to us in order to confirm Susac syndrome, due to bilateral visual loss. Funduscopic examination revealed peripheral retinal microangiopathy. Discussion: Susac syndrome is typically characterized by the clinical triad of encephalopathy, branch retinal artery occlusions, and hearing loss. In our case, ophthalmic findings were atypical. Interrupted vessels and microaneurisms accumulation in the peripheral retina of both eyes were observed.

The Role of Macrocyclic Receptors in Organization of Metal Centers

The coordination properties of saturated aza or oxa-aza macrocyclic receptors are strictly dependent on their molecular topology. In order to rationalize the relationship between structural features and binding characteristics of such molecules we have studied the coordination behavior of different macrocyclic or macropolycyclic oxa-aza ligands towards metal cations. Depending on molecular topology, a variety of inorganic chemical species can be lodged inside the receptor’s cavity, such as simple metal ions, complexed inorganic anions, partially hydrated metal cations or binuclear assemblies.