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Biomedical subjects

Luigi Capasso

Publications and source records attributed to Luigi Capasso.

16 recordsLinked to original sources

Anterior chamber depth measurement before and after photorefractive keratectomy: comparison between IOL master and Orbscan II.

PURPOSE: To measure the anterior chamber depth (ACD) with 2 different devices before and after photorefractive keratectomy (PRK). DESIGN: Noncomparative case series. PARTICIPANTS: One hundred forty-three eyes of 143 patients who had undergone PRK with refractive errors ranging from -13.13 diopters (D) to +7 D (mean, -3.67+/-3.58) were analyzed. METHODS: The ACD values preoperatively and at 1, 3, and 6 months postoperatively were measured with the Orbscan II and IOL Master. The results were analyzed using the Pearson correlation. MAIN OUTCOME MEASURE: Anterior chamber depth. RESULTS: The instruments showed good agreement between the measurements before and after surgery. A significant decrease between the preoperative and 1-month postoperative measurements was found in the ACD measured from the epithelium with Orbscan II (P<0.01) and IOL Master (P<0.01). A nonsignificant decrease with both IOL Master (P>0.01) and Orbscan II (P>0.01) was found between 3 and 6 months after surgery. The ACD measured from the endothelium using the Orbscan II showed a significant difference only between the 3- and 6-month follow-up data (P<0.01). CONCLUSIONS: The 2 devices showed good agreement, and the changes detected postoperatively seem to be related not only to corneal thinning but also to anterior segment remodeling.

Adolescent↗

Reliability of a new correcting factor in calculating intraocular lens power after refractive corneal surgery.

PURPOSE: To test the reliability of a corneal radius correcting factor (R factor) in calculating intraocular lens (IOL) power in eyes that developed cataract after refractive surgery and compare it with the clinical history (CHM) and double-K (DKM) methods. SETTING: Department of Ophthalmology, Second University of Naples, Naples, Italy. METHODS: Nineteen eyes from the literature that underwent cataract extraction and IOL implantation after refractive surgery were used to compare actual postoperative and expected refractive errors utilizing the R factor, CHM, and DKM. Intraocular lens powers were calculated with 3 formulas: SRK/T, Hoffer Q and Holladay 1. The differences were evaluated with the Wilcoxon test and Spearman correlation. RESULTS: With the R factor SRK/T and Holladay 1 formulas gave the best results; 16 (84.2%) and 17 (89.5%) eyes were within +/-2 diopters (D) of emmetropia. With CHM, the best results were obtained using the SRK/T and Holladay 1 formulas; with both formulas 12 (63.2%) eyes were within +/-2 D of emmetropia. With DKM, the best results were obtained using SRK/T and Holladay 1 formulas; with both formulas 10 eyes (52.63%) were in the range of +/-2 D from emmetropia. CONCLUSIONS: The R factor can be used with the SRK/T or Holladay 1 formula because this method seems comparable or superior to DKM and CHM.

Cataract Extraction↗

Reliability of the IOLMaster in measuring corneal power changes after photorefractive keratectomy.

PURPOSE: To test the accuracy of the IOLMaster (Carl Zeiss) in detecting corneal power changes after photorefractive keratectomy (PRK). SETTING: Department of Ophthalmology, 2nd University of Naples, Naples, Italy. METHODS: Two hundred twenty-five consecutive eyes that had PRK (mean -5.13 diopters [D] +/- 2.98 [SD] [range +0.25 to -16.25 D]) were analyzed. The data included preoperative and postoperative (1, 3, and 6 months) subjective refraction and computerized keratometry. Statistical analysis was performed to determine the correlation between the changes in the subjective refraction at the corneal plane and the changes in keratometry. RESULTS: The mean difference between the changes in refraction and the measured corneal changes was 0.75 +/- 1.13 D (range -3.84 to +7.68 D) at 1 month, 0.92 +/- 1.10 D (range -0.87 to +7.93 D) at 3 months, and 0.75 +/- 0.98 D (range -1.70 to +3.85 D) at 6 months. The difference was significant (P<.001). CONCLUSION: Automated keratometry provided by the IOLMaster did not accurately reflect the effective refractive changes after PRK, particularly in eyes that had a high dioptric treatment.

Adult↗

Expulsive hemorrhage before phacoemulsification.

A 65-year-old white man who was scheduled for cataract extraction experienced a sudden increase in intraocular pressure (IOP) with flattening of the anterior chamber immediately after the anterior capsule incision. The eye was sutured, and because no decrease in pressure was noted, surgery was postponed. The presence of the cataract prevented ophthalmoscopic examination. Echographic examination revealed a hemorrhagic choroidal detachment with involvement of the ciliary body. The patient was examined regularly until the choroidal detachment disappeared 4 weeks later. He then had uneventful phacoemulsification and intraocular lens implantation.

Aged↗

A new method of calculating intraocular lens power after photorefractive keratectomy.

PURPOSE: To find a method of calculating intraocular lens (IOL) power that may be independent of preoperative data, in eyes that have developed a cataract after refractive surgery. METHODS: Prior to and 1 month after PRK, the SRK/T formula was used to calculate IOL power in 88 eyes of 65 patients with a preoperative spherical equivalent refraction between -16.25 to +0.25 D (mean -5.39 +/- 3.19 D). IOL power was calculated by utilizing the spherical equivalent refraction as target both before and after PRK. Utilizing the postoperative corneal radius measurement (R2), an underestimation of the IOL power was found. For this reason, the mean postoperative corneal radius (R3) that gave the same IOL power found before surgery was calculated for each patient. The R3/R2 ratios were plotted against the axial eye length and a linear regression formula was used to calculate R2 correcting factors that gave the new corneal radius (R4). Patients were divided into classes according to axial eye length, and the mean R3/R2 ratios for each class were calculated and used to recalculate the new mean radius (R5). IOL power for emmetropia was calculated in all patients by utilization of R3, R4, R5, the historical method, and the "true corneal power" method. RESULTS: Within +/-0.50 D from the IOL power calculated with R3, R4 gave 35 (39.3%) IOLs, while R5 gave 40 (45.5%) IOLs; the clinical history method gave 24 (27.3%) IOLs and "true corneal power" gave 23 (26.1%) IOLs, with a statistically significant difference P<.001). CONCLUSIONS: Our theoretical method, based on correlation between axial eye length and corneal radius correcting factors, may represent an effective method of calculating IOL power after PRK, especially if the history of the patient is unknown.

Adult↗

Correlation of changes in refraction and corneal topography after photorefractive keratectomy.

PURPOSE: To establish which corneal power evaluation measured with corneal topography correlates best with refractive changes after photorefractive keratectomy (PRK) for myopia. METHODS: Two hundred fifty-one consecutive eyes of 171 patients who had PRK for myopia ranging from -14.80 to -0.50 D (mean -5.43 +/- 2.978 D), calculated at the corneal plane, were included in the analysis. Data included preoperative and postoperative (1, 3, and 6-mo) subjective refraction and videokeratography with a Keratron Scout (Optikon 2000). Statistical analysis was performed to determine the correlation between the change in subjective refraction at the corneal plane and changes in six corneal power measurements: best fit sphere, simulated keratometry (Sim K), corneal apex, and center of the pupil (last two evaluated for axial and meridional curvatures). RESULTS: The closest correlation between subjective refraction change and corneal power measurement during the three follow-up evaluations was found with Sim K (R2 = 0.904; 0.889; 0.854) and best fit sphere (R2 = 0.919; 0.909; 0.872), whereas the other measurements showed poor correlation with the different curvatures. CONCLUSIONS: The best fit sphere corneal topography parameter correlated best with the refractive changes, primarily for low treatment amounts, whereas it showed a clear-cut underestimation in eyes that had undergone high dioptric treatments.

Adult↗

Axial eye length evaluation before and after myopic photorefractive keratectomy.

PURPOSE: To test the accuracy of a new device (IOL Master; Carl Zeiss, Jena, Germany) in detecting axial eye length changes after photorefractive keratectomy (PRK). METHODS: Pre- and postoperative (1, 3, and 6 months) subjective refraction and axial eye length measurements were performed in 184 consecutive eyes that underwent PRK with the Nidek EC5000 excimer laser (Nidek Technologies, Gamagori, Japan) to treat refractive errors from +0.25 to -16.25 diopters (D) (mean: -5.12 +/- 3.01 D). RESULTS: The axial eye length measurements ranged from 22.51 to 31.32 mm (mean: 25.61 +/- 1.47 mm) before PRK; from 22.39 to 31.10 mm (mean: 25.48 +/- 1.43 mm) 1 month after PRK; from 23.17 to 31.14 mm (mean: 25.61 +/- 1.36 mm) 3 months after PRK; and from 23.36 to 29.68 mm (mean: 25.58 +/- 1.35 mm) 6 months after PRK. Preoperative and 1-month postoperative data showed a statistically significant difference (P<.001), whereas no significant difference was found between 1 and 3 months (P=.0137) or 3 and 6 months (P=.2422). CONCLUSIONS: The IOL Master showed a decrease in the axial eye length measurement larger than the theoretical ablation depth and the difference increased as the correction became higher.

Adolescent↗