Publicação
Influência de Parâmetros Biométricos Opcionais nas Fórmulas de Cálculo da Potência da Lente Intraocular
| Resumo: | Introduction: Modern intraocular lens (IOL) power calculation formulas depend on a set of mandatory biometric parameters (axial length, keratometry, anterior camera depth), but also allow the introduction of optional biometric parameters that may not be measurable by older optical biometry devices. As an example, Barrett Universal II (UII) and Kane formulas include optional parameters such as crystalline lens thickness and white white distance or crystalline lens thickness and central corneal thickness, respectively. Given the current scientific gap regarding the effect of these optional variables on refractive outcomes, we compare the results of uncomplicated cataract surgery with and without the use of optional parameters. Materials and Methods: Observational retrospective consecutive case study of eyes submitted to uncomplicated cataract surgery with trifocal diffractive IOL implantation (Alcon PanOptix®, Alcon Labs TX, USA) in which we compared the spherical equivalent (SE) predicted for the implanted lens, obtained by Barrett UII and Kane formulas, with the postoperative SE obtained by subjective refraction 6 to 12 weeks after surgery. To evaluate the influence of the optional parameters on Barrett UII and Kane formulas, we performed a back-calculation with and without those variables. Primary outcomes included mean absolute error (MAE), median absolute errors (MedAE), mean arithmetic error and standard error, obtained with and without the inclusion of optional parameters for both formulas. Results: Seventy nine eyes from 79 patients were included (n=79). After optimization, the MAE obtained was 0.208 through the Barrett UII formula and 0.191 through the Kane formula (p>0.05) without including optional variables. The MedAE was 0.144 and 0.166, respectively (p>0.05). With the inclusion of both optional parameters, the postoperative SE prediction changed by more than 0.1 D (absolute values) in only 15.2% (n=12) and 17.7% (n=14) of the eyes, respectively. Only half of these cases showed improvement of the postoperative prediction of refractive power (n=6 and n=7, respectively), with a worse prediction in the remaining 50%. Discussion: These results show that it is possible to obtain good results without using optional parameters, which are not measured by some older biometers still used. Conclusion: In our study, the inclusion of optional biometric parameters in the Barrett UII and Kane formulas provided no significant refractive benefit. |
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| Autores principais: | Pinto, Maria Inês Correia da Fonseca |
| Assunto: | Biometria Extração de Catarata Lentes Intraoculares Algoritmos Biometry Cataract Extraction Lenses, Intraocular Algorithms |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Coimbra |
| Idioma: | português |
| Origem: | Estudo Geral - Universidade de Coimbra |
| Resumo: | Introduction: Modern intraocular lens (IOL) power calculation formulas depend on a set of mandatory biometric parameters (axial length, keratometry, anterior camera depth), but also allow the introduction of optional biometric parameters that may not be measurable by older optical biometry devices. As an example, Barrett Universal II (UII) and Kane formulas include optional parameters such as crystalline lens thickness and white white distance or crystalline lens thickness and central corneal thickness, respectively. Given the current scientific gap regarding the effect of these optional variables on refractive outcomes, we compare the results of uncomplicated cataract surgery with and without the use of optional parameters. Materials and Methods: Observational retrospective consecutive case study of eyes submitted to uncomplicated cataract surgery with trifocal diffractive IOL implantation (Alcon PanOptix®, Alcon Labs TX, USA) in which we compared the spherical equivalent (SE) predicted for the implanted lens, obtained by Barrett UII and Kane formulas, with the postoperative SE obtained by subjective refraction 6 to 12 weeks after surgery. To evaluate the influence of the optional parameters on Barrett UII and Kane formulas, we performed a back-calculation with and without those variables. Primary outcomes included mean absolute error (MAE), median absolute errors (MedAE), mean arithmetic error and standard error, obtained with and without the inclusion of optional parameters for both formulas. Results: Seventy nine eyes from 79 patients were included (n=79). After optimization, the MAE obtained was 0.208 through the Barrett UII formula and 0.191 through the Kane formula (p>0.05) without including optional variables. The MedAE was 0.144 and 0.166, respectively (p>0.05). With the inclusion of both optional parameters, the postoperative SE prediction changed by more than 0.1 D (absolute values) in only 15.2% (n=12) and 17.7% (n=14) of the eyes, respectively. Only half of these cases showed improvement of the postoperative prediction of refractive power (n=6 and n=7, respectively), with a worse prediction in the remaining 50%. Discussion: These results show that it is possible to obtain good results without using optional parameters, which are not measured by some older biometers still used. Conclusion: In our study, the inclusion of optional biometric parameters in the Barrett UII and Kane formulas provided no significant refractive benefit. |
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