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Biomedical subjects

M Portellos

Publications and source records attributed to M Portellos.

4 recordsLinked to original sources
PubMed1998

Cataract surgery and intraocular lens implantation in patients with retinoblastoma.

OBJECTIVE: To report the visual outcome and complications after extracapsular cataract extraction with posterior chamber intraocular lens (IOL) implantation in eyes that underwent external beam radiotherapy for the treatment of retinoblastoma. METHODS: Eleven eyes of 8 patients aged 1.5 to 8.0 years at the time of surgery for irradiation-induced cataract were observed for 6 to 39 months (mean [+/-SD], 20+/-10 months). A standard technique of extracapsular cataract extraction, posterior chamber IOL implantation, pars plana posterior capsulotomy, and pars plana anterior vitrectomy was performed in 9 eyes, and secondary IOL placement was performed in 2 eyes. RESULTS: All eyes that underwent primary IOL implantation achieved visual acuities equal to or better than those best ever recorded prior to the development of the cataract. There were no postoperative complications, and all eyes experienced minimal postoperative inflammation. The 2 eyes that underwent secondary IOL implantation achieved their best-corrected aphakic visual acuities but experienced a prolonged course of postoperative inflammation. CONCLUSION: Intraocular lens placement in the posterior chamber of eyes with regressed retinoblastoma and irradiation-induced cataract seems to be a safe and effective method for the correction of aphakia.

Cataract↗
PubMed1998

Topical versus oral carbonic anhydrase inhibitor therapy for pediatric glaucoma.

PURPOSE: Our purpose was to compare, in a crossover design,the hypotensive effect of oral acetazolamide (Diamox) and topical dorzolamide (Trusopt) in patients with pediatric glaucoma. METHODS: All patients less than 18 years old who were switched from acetazolamide to dorzolamide without other intervention were reviewed. Intraocular pressures were obtained with either a Tono-Pen (Mentor Ophthalmics, Santa Barbara, Calif.) or applanation tonometer. Minimum follow-up times on acetazolamide and on dorzolamide were 1 month (mean 12.2 +/- 19.7 months) and 2 months (mean 8.2 +/- 5.1 months), respectively. The average dose of acetazolamide was 9.9 +/- 1.8 mg/kg/day. RESULTS: Eleven eyes (11 patients) were included. Indications for crossover from oral to topical carbonic anhydrase inhibitor (CAI) therapy were intolerance to acetazolamide (6 eyes) and surgical intervention in the fellow eye (5 eyes). The mean age at the time of crossover was 7.4 +/- 3.0 years. A comparison of intraocular pressure (IOP) before addition of a CAI was made in 8 eyes. The mean IOP off of a CAI was 27.8 +/- 4.9 mm Hg. The mean 10P was reduced to 18.5 +/- 4.3 mm Hg on acetazolamide (mean percent IOP reduction 35.7% +/- 15.6%, p < 0.01) and to 22.2 +/- 5.4 mm Hg on dorzolamide (mean percent IOP reduction 27.4% +/- 17.1%, p < 0.01). All 11 eyes showed an increase in IOP when switched from acetazolamide to dorzolamide, with a mean increase of 3.7 +/- 2.5 mm Hg (20.2% -/+ 13.7%, p < 0.01). Five eyes have remained controlled on dorzolamide and a topical beta-blocker. Five eyes required further intervention for the control of glaucoma. One eye was switched back to acetazolamide for better IOP control. CONCLUSION: Although not as effective as oral acetazolamide, topical dorzolamide causes a significant IOP reduction in this group of pediatric glaucoma patients and appears to be well tolerated.

Acetazolamide↗
PubMed1995

Effects of adenosine on ocular blood flow.

PURPOSE: To determine the effect of intravascular adenosine on blood flow in the ocular fundus and to examine indirectly whether the blood-brain barrier to adenosine, which exists in the cerebrovasculature of the cat, is present in the eye of this animal. METHODS: The noninvasive techniques of laser Doppler flowmetry and velocimetry along with fundus photography were used to measure the change in optic nerve head and choroidal and retinal blood flow during intravenous infusions of 0.18 and 0.6 mg/kg per minute of adenosine. RESULTS: Infusions of adenosine induced significant increases in choroidal blood flow (60% with 0.6 mg/kg per minute) but not in optic nerve head or retinal blood flows. CONCLUSIONS: The lack of effect of intravenously infused adenosine on the optic nerve and retinal circulations is most likely caused by the tight junctions in the vessels of these vascular beds, which prevent adenosine from reaching its receptors. Perivascular adenosine in the choroid most likely accounts for the increase in blood flow in this tissue.

Adenosine↗