From left: Dr Audrey Talley Rostov, Dr Tun Kuan Yeo and Avni Parikh.
Ophthalmologists at the recent Australasian Society of Cataract Refractive Surgeons’ (AUSCRS) conference in Noosa were invited to attend a Bausch & Lomb breakfast at which Dr Audrey Talley Rostov from the United States and Dr Tun Kuan Yeo from Singapore, spoke about the enVista intraocular monofocal lens (IOL).
The enVista is a toric or non-toric, glistening free hydrophobic acrylic biconvex IOL, manufactured from a new, modified material that allows for faster unfolding. It is available with a wide IOL power range, from 0 to +34D.
Describing the enVista toric IOL as her ‘go to lens’ Dr Talley Rostov, from Northwest Eye Surgeons in Seattle, said this IOL is most suitable for complex cases, including patients who have had previous refractive surgery, are dissatisfied with their current IOLs, or have irregular topographies or zonular issues.
Dr Rostov said being abberation neutral, she implants the IOL in eyes with both regular and irregular astigmatism.
“With no added spherical aberration, it doesn’t matter if the IOL is a bit off centre or if you have a high angle kappa or high angle alpha – you can still achieve good results. Even if you do get some lens decentration, you will achieve good results because the lens has the same power all the way through; you won’t get any reduced contrast or blur,” she said.
Being aberration free, Dr Rostov said the enVista IOL is also ideal for the irregular topographies of keratoconic patients.
“You’re not adding anything to their existing abberations so, while you will never achieve perfect vision, it will be as good as it possibly can be,” she explained.
Dr Rostov also noted the ease with which the enVista can be explanted if necessary.
For the greatest success, Dr Rostov stressed the need to optimise the ocular surface ahead of surgery. Any pterygium, Salzmann nodular degeneration, astigmatism due to ocular surface disease, or dry eye disease for example, needs to be corrected as these can all affect your IOL calculation and therefore your choice of IOL, which will impact the patient’s outcome. She puts every patient, who presents for a premium IOL and wants limited use of glasses afterwards, on a dry eye treatment for at least two weeks ahead of surgery to thoroughly prepare the ocular surface.
Dr Tun Kuan Yeo from Singapore Tan Tock Seng Hospital spoke about his experience implanting the eVista IOL in his own country. Describing this lens as his “lens of choice” for both routine and complex cases, he said he likes how it unfolds much faster, especially in toric patients. Additionally, he noted its neutral aspheric, aberration free optics, which provide greater depth of focus, making it ideal for patients with zonulopathy and abnormal corneas.
Turning his attention to the formulas he uses to calculate enVista IOLs for patients, Dr Yeo spoke extensively about the Emmetropia Verifying Optical (EVO 2.0) formula (www.evoiolcalculator.com), which was included in a 2020 comparison of 13 IOL formulas published in Clinical Ophthalmology (Diogo Hipolito-Fernandes et al). The EVO 2.0, Kane, and VRF-G were identified as the most accurate for short, medium and long axial lengths.
The EVO 2.0 suite of formulae includes the EVO IOL formula, the EVO toric formula and the EVO for post myopic refractive surgery.
Having presented a variety of case studies, Dr Yeo concluded by stating that the EVO IOL formula provides high accuracy for all axial lengths and even in settings of complex cases such as toric procedures, post-myopic laser refraction and for making predictions using axial length and corneal power only, when anterior chamber depth and lens thickness measurements are erroneous. The new enVista Toric Calculator now incorporates the EVO 2.0 Formula.
Dr Rostov and Dr Yeo consult to Bausch & Lomb.