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Factors Influencing Efficacy of Peripheral Corneal Relaxing Incisions during Cataract Surgery.

Hirnschall N, Wiesinger J, Draschl P, Findl O - J Ophthalmol (2015)

Bottom Line: Results.Mean corneal astigmatism was reduced to 1.14 D (±0.67; 0.11 to 3.89) 4 months postoperatively.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: Vienna Institute for Research in Ocular Surgery (VIROS), A Karl Landsteiner Institute, Hanusch Hospital, 1140 Vienna, Austria.

ABSTRACT
Purpose. To evaluate influencing factors on the residual astigmatism after performing peripheral corneal relaxing incisions (PCRIs) during cataract surgery. Methods. This prospective study included patients who were scheduled for cataract surgery with PCRIs. Optical biometry (IOLMaster 500, Carl Zeiss Meditec AG, Germany) was taken preoperatively, 1 week, 4 months, and 1 year postoperatively. Additionally, corneal topography (Atlas model 9000, Carl Zeiss Meditec AG, Germany), ORA (Ocular Response Analyzer, Reichert Ophthalmic Instruments, USA), and autorefraction (Autorefractometer RM 8800 Topcon) were performed postoperatively. Results. Mean age of the study population (n = 74) was 73.5 years (±9.3; range: 53 to 90) and mean corneal astigmatism preoperatively was -1.82 D (±0.59; 1.00 to 4.50). Mean corneal astigmatism was reduced to 1.14 D (±0.67; 0.11 to 3.89) 4 months postoperatively. A partial least squares regression showed that a high eccentricity of the cornea, a large deviation between keratometry and topography, and a high preoperative astigmatism resulted in a larger postoperative error concerning astigmatism. Conclusions. PCRI causes a reduction of preoperative astigmatism, though the prediction is difficult but several factors were found to be a relevant source of error.

No MeSH data available.


Related in: MedlinePlus

Cumulative frequency for the difference vector between the aimed and the measured corneal astigmatisms for different eccentricities of the cornea (blue = low eccentricity and red = high eccentricity).
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fig4: Cumulative frequency for the difference vector between the aimed and the measured corneal astigmatisms for different eccentricities of the cornea (blue = low eccentricity and red = high eccentricity).

Mentions: In a next analysis step all cases were equally allocated according to their eccentricity of the cornea in two groups (eccentricity ≤ 0.52 versus eccentricity > 0.52). The cut-off value was defined by the median of the eccentricity of the cornea in the study population. Although patients with a lower eccentricity of the cornea showed a lower deviation from the aimed astigmatism (0.99; SD: 0.60; range: 0.30 to 1.93) compared to those corneas with a higher eccentricity (1.28; SD: 0.64; range: 0.31 to 2.18), this difference was not found to be significant (Wilcoxon signed rank test: p = 0.303) (Figure 4).


Factors Influencing Efficacy of Peripheral Corneal Relaxing Incisions during Cataract Surgery.

Hirnschall N, Wiesinger J, Draschl P, Findl O - J Ophthalmol (2015)

Cumulative frequency for the difference vector between the aimed and the measured corneal astigmatisms for different eccentricities of the cornea (blue = low eccentricity and red = high eccentricity).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4496490&req=5

fig4: Cumulative frequency for the difference vector between the aimed and the measured corneal astigmatisms for different eccentricities of the cornea (blue = low eccentricity and red = high eccentricity).
Mentions: In a next analysis step all cases were equally allocated according to their eccentricity of the cornea in two groups (eccentricity ≤ 0.52 versus eccentricity > 0.52). The cut-off value was defined by the median of the eccentricity of the cornea in the study population. Although patients with a lower eccentricity of the cornea showed a lower deviation from the aimed astigmatism (0.99; SD: 0.60; range: 0.30 to 1.93) compared to those corneas with a higher eccentricity (1.28; SD: 0.64; range: 0.31 to 2.18), this difference was not found to be significant (Wilcoxon signed rank test: p = 0.303) (Figure 4).

Bottom Line: Results.Mean corneal astigmatism was reduced to 1.14 D (±0.67; 0.11 to 3.89) 4 months postoperatively.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: Vienna Institute for Research in Ocular Surgery (VIROS), A Karl Landsteiner Institute, Hanusch Hospital, 1140 Vienna, Austria.

ABSTRACT
Purpose. To evaluate influencing factors on the residual astigmatism after performing peripheral corneal relaxing incisions (PCRIs) during cataract surgery. Methods. This prospective study included patients who were scheduled for cataract surgery with PCRIs. Optical biometry (IOLMaster 500, Carl Zeiss Meditec AG, Germany) was taken preoperatively, 1 week, 4 months, and 1 year postoperatively. Additionally, corneal topography (Atlas model 9000, Carl Zeiss Meditec AG, Germany), ORA (Ocular Response Analyzer, Reichert Ophthalmic Instruments, USA), and autorefraction (Autorefractometer RM 8800 Topcon) were performed postoperatively. Results. Mean age of the study population (n = 74) was 73.5 years (±9.3; range: 53 to 90) and mean corneal astigmatism preoperatively was -1.82 D (±0.59; 1.00 to 4.50). Mean corneal astigmatism was reduced to 1.14 D (±0.67; 0.11 to 3.89) 4 months postoperatively. A partial least squares regression showed that a high eccentricity of the cornea, a large deviation between keratometry and topography, and a high preoperative astigmatism resulted in a larger postoperative error concerning astigmatism. Conclusions. PCRI causes a reduction of preoperative astigmatism, though the prediction is difficult but several factors were found to be a relevant source of error.

No MeSH data available.


Related in: MedlinePlus