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E Balestrazzi

Publications and source records attributed to E Balestrazzi.

60 records · Page 4Linked to original sources
PubMedDate not supplied

Role of the corneal epithelium in refractive changes following laser in situ keratomileusis for high myopia.

PURPOSE: Epithelial hyperplasia is one of the factors that plays a role in myopic regression after photorefractive keratectomy (PRK). We evaluated the role of the epithelium following excimer laser in situ keratomileusis (LASIK) performed on highly myopic eyes. METHODS: Fifty eyes of 32 patients (18 females and 14 males; mean age, 31.7+/-6.5 years) were treated with LASIK for myopia with an attempted correction ranging between -8.50 and -12.25 D (mean, -10.48+/-1.43 D). No sutures were placed. The thickness of the central epithelium was evaluated either with a 50-MHz ultrasonic pachymeter or an ultrasound biomicroscope. Postoperatively, topical corticosteroid drops were administered for at least 1 month. RESULTS: Follow-up was at least 12 months. Epithelium measurements were thicker compared to preoperative measurements from the first week postoperatively (mean, +1.9 microm, +2.77%; P<.05). Epithelial thickness peaked at the third month after LASIK (mean, +6.5 microm, +9.5%; P<.05) and remained stable through 12 months. A negative correlation between epithelium thickness and manifest refraction from the first month postoperatively to the end of follow-up was present. CONCLUSION: The epithelium seemed to have a role in the regression of refractive effect after LASIK to correct high myopia.

Adult↗
PubMedDate not supplied

Effectiveness of LASIK to correct refractive error after penetrating keratoplasty.

OBJECTIVE: Refractive errors may invalidate the good results of penetrating keratoplasty (PK). The Authors evaluate the effectiveness of excimer laser in situ keratomileusis (LASIK) in the correction of refractive error after PK. MATERIALS AND METHODS: Four patients, a 26-year-old woman, a 54-year-old man, a 19-year-old man, and a 51-year-old woman, showed refractive errors: -11 = -4.5 x 85 ; -8, -4.5 = -11 x 95 ; and -4.5 = -4 x = 1200, with a clear graft at least 20 months after penetrating keratoplasty secondary to keratoconus. However, they underwent the LASIK procedure with a nasal-hinged flap of 160 um. No sutures were placed. RESULTS: At follow-up, 24, 18, 12, and 12 months, respectively, the graft remained clear and the endothelial cells were unchanged. The uncorrected visual acuities were 20/50, 20/25, 20/50, and 20/25, respectively with an unchanged best corrected visual acuity (20/20) for all patients. No significant complications were observed. CONCLUSIONS: LASIK procedure seems to be an effective technique to correct refractive error after successful penetrating keratoplasty.

Adult↗
PubMedDate not supplied

Measurement of corneal thickness by ultrasound after photorefractive keratectomy in high myopia.

BACKGROUND: Photorefractive keratectomy (PRK) has been used to treat myopia in human eyes since 1988. METHODS: We evaluated corneal ablation depth after excimer laser myopic photorefractive keratectomy with the Summit Technology ExciMed UV200LA laser. Preoperative refraction was: mean 9.58 diopters (D) +/- 2.01, (range 6 to 17). We used ultrasound pachometry (1640 m/sec) in 40 eyes of 33 patients. Mean follow-up was of 49.5 weeks (range 16 to 76). RESULTS: The measurement of the corneal thickness showed a reduction of the initial thickness followed by an inconsistent increase caused by wound healing and tissue proliferation. CONCLUSION: The data showed no direct correlation between diopters of refractive correction and the change in corneal thickness.

Cell Division↗
PubMedDate not supplied

Histological, immunohistochemical, and ultrastructural findings in human corneas after photorefractive keratectomy.

BACKGROUND: Four human corneas that had undergone photorefractive keratectomy (PRK) and subsequent penetrating keratoplasty were examined by means of light and electron microscopy in an attempt to detect possible causes for complications after PRK. METHODS: Four eyes with a central corneal leukoma resulting from a previous PRK treatment underwent penetrating keratoplasty respectively 3 days, 3 months, 5 months, and 13 months after the refractive procedure. Different excimer laser instruments (Meditec MEL 50, Summit UV200, and VISX 20/20) had been used. The corneal buttons removed were submitted for light microscopy, electron microscopy and immunohistochemistry. RESULTS: An immature (one to two layers, basement membrane anomalies) but continuous epithelium was present even in the 3-day specimen; between six and eight epithelial layers could be seen in the 13-month specimen, which still presented an undulated aspect of the otherwise normal basement membrane. A continuous acellular collagen layer underlying the epithelium of the ablated area was detected in the superficial stroma of all examined corneas. No Descemet's membrane or endothelial alterations could be seen. CONCLUSIONS: Despite recovery of a continuous epithelial layer as early as 3 days after PRK, abnormalities of both epithelium and superficial stroma could be detected in all specimens, including the one obtained 13 months after the refractive procedure.

Adult↗
PubMedDate not supplied

Effect of centering excimer laser PRK on refractive results: a corneal topography study.

Computer-assisted analysis of corneal topography, using an EyeSys Corneal Analysis System instrument, was performed on 20 normally sighted human eyes that underwent excimer laser photorefractive keratectomy (PRK) to correct high myopia from 6.00 to 17.00 D (mean 10.90 +/- .SD 2.90 D). Ablations utilized one or two zones, at a single time, with an ExciMed UV200 193-nanometer excimer laser (Summit Technology, Inc, Waltham, Mass). Mean follow up was 28.9 weeks (+/- 13). Decentered treatment caused an average error of 1.06 D in the attempted refractive result.

Adolescent↗