Improving toric intraocular lens calculations using total surgically induced astigmatism for a 2.5 mm temporal incision
| Autor: | George Pettit, Jack T. Holladay |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Male
medicine.medical_specialty genetic structures medicine.medical_treatment Intraocular lens Cataract Extraction Surgical planning law.invention 03 medical and health sciences 0302 clinical medicine Postoperative Complications Lens Implantation Intraocular law Ophthalmology Medicine Humans Aged Retrospective Studies Lenses Intraocular Keratometer business.industry Calculation algorithm Astigmatism Cataract surgery Middle Aged eye diseases Sensory Systems Meridian (perimetry visual field) 030221 ophthalmology & optometry Surgery Surgically induced astigmatism Female sense organs business Temporal incision 030217 neurology & neurosurgery Algorithms |
| Zdroj: | Journal of cataract and refractive surgery. 45(3) |
| ISSN: | 1873-4502 |
| Popis: | Purpose To determine in cataract surgery the total surgically induced astigmatism (SIA) that accounts for all factors that contribute to the difference between preoperative keratometric and postoperative refractive astigmatism other than any toricity of an intraocular lens (IOL). Setting Twenty surgical sites in the United States. Design Retrospective case series. Methods An analysis was performed of 4 clinical trials involving toric IOLs and nontoric IOLs in standard cataract surgery. Data included preoperative keratometry and manifest refraction measurements at multiple postoperative visits. For each eye with a nontoric IOL, the total SIA vector was calculated as the vector difference between postoperative refractive and preoperative keratometric astigmatism. The relationship between the total SIA vector and meridian of preoperative keratometric astigmatism was determined and used to develop a new calculation algorithm for toric IOL implantation. The algorithm was tested retrospectively to identify optimum candidate eyes for various cylinder power toric IOLs as well as to compare results with the Barrett toric calculator. Results The total SIA vector was a significant contributor to surgically associated astigmatic changes in eyes receiving nontoric IOLs. The total SIA vector was dependent on the preoperative steep meridian in a consistent fashion, allowing development of a new calculation algorithm for toric IOL correction. Retrospectively applying this algorithm to toric IOL cases led to significantly improved differences between toric and nontoric control populations. Conclusions Total SIA analysis is a new approach for toric IOL surgery. Because it considers all factors that may influence outcomes, the total SIA is a useful inclusion in toric IOL surgical planning. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|