Biomedical subjects

F I Camesasca

Publications and source records attributed to F I Camesasca.

8 recordsLinked to original sources

PubMed1997

Excimer laser photorefractive keratectomy for high myopia: four-year experience with a multiple zone technique.

PURPOSE: The purpose of the study is to evaluate the results of the authors' 4-year experience with excimer laser photorefractive keratectomy (PRK) and multiple optical zone corneal ablation in highly myopic eyes. METHODS: The authors retrospectively evaluated 56 eyes of 44 patients (mean refraction, -11.3 diopters [D]; range, -5.75 to -24.5 D) who underwent PRK with a Visx Model 20/20 laser (Visx, Santa Clara, CA). Preoperative visual acuity of 20/40 or better was present in 46 eyes. Corneal ablation was divided into concentric optical zones (4, 5, and 6 mm), allowing corrections of up to 18 D, with a refractive goal of within -1 D from emmetropia in 49 eyes. A hand-held fixation system was always used, and a nitrogen-blowing system (NBS) was used in the first 21 eyes only. RESULTS: Before retreatment, the range of final cycloplegic refraction from emmetropia in eyes treated with NBS versus not was within +/-1 D in 6 (28.6%) and 15 eyes (44.1%), between -1.25 and -3 D in 5 (23.8%) and 14 eyes (41.1%), and more than -3 D in 10 (47.6%) and 5 eyes (14.7%), respectively. No lines of visual acuity were lost in 37 eyes (80.4%) with 20/40 or better visual acuity before surgery. Three eyes showed vision loss due to worsening of myopic maculopathy and one due to corneal haze. Correction stabilized within 9 months, and at a mean time of 25.6 months, the correction attained was of -8.5 +/- 3.6 D, achieving 90.3% of attempted correction. Eyes with preoperative myopia less than -10 D (n = 27) showed regression less than -1 D in 8 eyes (29.6%), between -1.25 and -3.00 D in 5 eyes (18.5%), and greater than -3.00 D in 1 eye (3.7%); eyes with more than -10 D (n = 29) regressed in 3 (10.3%), 6 (20.7%), and 1 eye (3.4%), respectively. Severe haze was observed in 11 eyes (19.6%) 3 months after surgery. Two eyes showed decentration greater than 1.5 mm. At last examination, night driving problems were reported by 12 (41.4%) of 29 patients evaluated who drive. CONCLUSIONS: After the NBS was eliminated, the multiple-zone technique achieved a long-term, stable 83.1% reduction of preoperative myopia. Patients with severe myopia appreciated reduction of most of the refractive defect, although perception of halos was noted by 16 patients.

Adult↗

PubMed1993

Postoperative endophthalmitis resulting from prosthesis contamination in a monocular patient.

Monocular patients who wear an ocular prosthesis may harbor pathogenic conjunctival flora both in the socket and in the contralateral eye. They may therefore be at increased risk of developing endophthalmitis after intraocular procedures. We studied a monocular, prosthesis-wearing, 86-year-old man who underwent cataract extraction, subtotal transpupillary vitrectomy, and intraocular lens insertion. Fulminant endophthalmitis ensued postoperatively, and despite complete vitrectomy and administration of intraocular antibiotics, the eye lost light perception. Intravitreal as well as conjunctival cultures bilaterally grew Proteus mirabilis. The patient disclosed that he cleaned the prosthesis frequently because of discharge. We considered an association between this bacterial colonization and the risk of developing postoperative endophthalmitis and suggest prophylactic measures for treatment of monocular patients undergoing intraocular procedures.

Aged↗

PubMed1993

Influence of silicone oil on iris microangiopathy in diabetic vitrectomized eyes.

PURPOSE: This study evaluates the influence of intraocular silicone oil on iris diabetic microangiopathy in diabetic vitrectomized eyes. METHODS: The authors examined 20 eyes of 20 patients with diabetes undergoing primary vitrectomy for fractional diabetic retinal detachment, endophotocoagulation, and 1000 centistokes silicone oil tamponade. The vascular status of the iris in these eyes was examined by iris fluorescein angiography once before silicone oil injection and again when it was removed (mean follow-up, 8.3 months). RESULTS: Iris diabetic microangiopathy, including breakdown of the blood-iris barrier and iris neovascularization, improved or remained stable in 40% of eyes. It worsened in 60% of eyes, including all aphakic eyes. Neovascular glaucoma developed in one of them. A significant correlation was found between worsening of iris diabetic microangiopathy and both aphakia (P = 0.01) and severe immediate postvitrectomy inflammation (P = 0.02). Eyes with recurrent retinal detachment (n = 4) showed worsening of iris diabetic microangiopathy, but this was not significantly correlated. CONCLUSION: Aphakic vitrectomized eyes have a higher risk of iris diabetic microangiopathy developing, even after silicone oil tamponade. Immediate postoperative intraocular inflammation also is a risk factor for worsening of iris diabetic microangiopathy in phakic eyes. Recurrence of retinal detachment was not significantly correlated with worsening of iris status.

Adult↗

PubMed1993

Cystoid macular oedema after extracapsular cataract extraction and intraocular lens implantation in diabetic patients without retinopathy.

Postoperative onset or aggravation of cystoid macular oedema (CMO) in diabetic patients after extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation is a frequent problem. At present little is known about the occurrence and prognosis of this complication in diabetics with no clinically detectable diabetic retinopathy (DR). Twenty five diabetic eyes (24 subjects) without DR and 45 normal eyes (44 subjects) were studied before surgery and 30, 90, 180, 360 days after ECCE and posterior chamber IOL implantation. Fluorescein angiography was performed at each examination. The frequency of angiographic CMO in the two groups was comparable 30 days after surgery but was significantly higher in diabetic eyes at 90, 180, and 360 days. This finding is probably related to an impairment of the blood-retinal barrier in diabetics. Final visual acuity, however, was similar in the two groups.

Aged↗

PubMed1992

Peripheral retinal changes and axial myopia.

The relationship between the presence of peripheral chorioretinal changes and axial myopia in 513 eyes (513 patients) 24 mm or more in length, or beyond the upper range of normal axial length, is studied. Axial length was measured with A-scan ultrasonography (immersion technique) and retinal periphery was studied by biomicroscopic examination and scleral indentation. The presence of lattice degeneration, pavingstone degeneration, pigmentary degeneration, white with or without pressure (WWP), retinal holes, tears, or both (RHT), retinal detachment, and posterior vitreous detachment was reported. The correlation between presence of a lesion and a longer axial length was always significant, except with retinal detachment, pigmentary degeneration, and RHT. Pavingstone degeneration was significantly related to older age and WWP and RHT to younger age. Posterior vitreous detachment was frequent in almost all axial length groups and age classes. No significant relationship was found between any kind of lesion and gender of the patient, or between axial length and patient age.

Adolescent↗

PubMed1991

Combined vitrectomy, cataract extraction, and posterior chamber intraocular lens implantation in diabetic patients.

Combined extracapsular cataract extraction, pars plana vitrectomy, and posterior chamber intraocular lens implantation was performed in six eyes with proliferative diabetic retinopathy. These eyes all had minimal iris vascular changes and were at reasonably low risk for developing intraoperative and postoperative complications. The surgery must be relatively brief and the endophotocoagulation accurate. Initial visual acuities ranged from light perception to 4/200. With an average follow-up of 9.7 months, final acuities ranged from 4/200 to 20/40.

Aged↗

PubMedDate not supplied

Prevention of corneal ectasia in laser in situ keratomileusis.

PURPOSE: Ectasia after laser in situ keratomileusis (LASIK) is a rare but serious complication. Prevention includes proper patient selection with detection of those at particular risk. Causes of ectasia include predisposition, excessive ablation with less than 250 microm of residual stromal bed, thicker than normal flap, irregular corneal thickness, and different ablation rates. METHODS: We evaluated corneal curvature patterns and their relationship to corneal topography and pachymetry maps. RESULTS: Corneal topography (axial, tangential, and altimetric) and pachymetry map characteristics of normally astigmatic corneas, keratoconus, false-positive and false-negative cases, as well as contact lens-induced warpage are discussed. CONCLUSIONS: Preoperative pachymetry maps for LASIK surgery allow accurate case selection through detection of borderline cases, and provide important documentation of preoperative status, as well as useful information for improving surgical strategy. Another important parameter is the asphericity index.

Cornea↗

PubMedDate not supplied

Decentration after refractive surgery.

PURPOSE: To examine factors useful in evaluation of suspect decentration after refractive surgery. METHODS: We evaluated 148 cases (eyes) referred to us for recentering procedures by review of information obtainable by evaluation of pupil position, corneal topography, and corneal curvature gradient. RESULTS: Only a minority of eyes (n=5, 3.4%) were truly decentered; in the remaining majority a high dioptric gradient with consequent focal scarring was present (n=107, 72.3%). In 28 eyes (18.9%), a drifting of the eye during treatment was responsible, and in eight eyes (5.4%), a central island was observed. CONCLUSIONS: Proper corneal topographical diagnosis reduces the risk of improperly suspecting decentration, and for most cases, smoothing of the central cornea is a simple and efficacious solution. Recommendations for the prevention of decentration include proper patient positioning, special care in treating high myopes, preoperative check of pupil displacement nasally, evaluation of preoperative map with detection of high temporal curvature gradient, and use of the cross-cylinder technique in the treatment of astigmatism.

Cornea↗