Blended vision software nomogram

Nearly all 605 presbyopic patients participating in a multicentre trial achieved binocular uncorrected 20/25 or better distance vision combined with J2 or better near vision three months after surgery using the Laser Blended Vision software nomogram, Jean-Francois Faure MD, Paris, told the XXIX ESCRS Congress. The nomogram was developed by Dan Z Reinstein MD, London, UK, for the Carl Zeiss Meditec MEL-80 excimer laser and VisuMax femtosecond laser platform.

Laser Blended Vision is designed to take advantage of a nonlinear aspheric ablation profile that increases depth of vision in each eye, Dr Faure noted. The fields are then combined using a micro-monovision approach that overlaps depth of field in each eye.

'The dominant eye has good vision from distance to intermediate. The non-dominant eye has good vision from near to intermediate. The brain merges the two images and a blended zone is created that provides patients with quality uncorrected visual acuity at near, intermediate and far,' Dr Faure explained.

The trial Dr Faure reported involved 243 male and 362 female patients from 39 to 71 years old. Preoperatively, 41 per cent were myopic with a mean spherical equivalent of -3.73 +/- 1.98 D ranging up to -10.25 and mean cylinder -0.91 +/- 0.70 ranging up to -4.74. Some 44 per cent were hyperopes with a mean spherical equivalent of +2.14 +/- 1.02 ranging up to +6.75 with mean cylinder -0.78 +/- 0.81 ranging up to -4.50. Another 15 per cent were emmetropes with mean spherical equivalent of +0.33 +/- 0.38 ranging from -0.50 to +0.75 with mean cylinder of -0.49 +/-0.92 ranging up to -4.50.

Each of the five centres was equipped with the same platform and each of the seven participating surgeons used the same operating procedures. Patients were assessed for ocular dominance, tolerance of micro-monovision, understanding of the procedure and suitability for LASIK. Target refraction was plano in the dominant eye and -0.75 to -1.5 D in the non-dominant eye. Data on age, refraction, gender, ocular dominance and degree of tolerance were loaded, and all treatment was determined using the Laser Blended Vision nomogram. Patients were followed at one day and three months after surgery.

For all five centres at three months, 78 per cent of emmetropes achieved binocular uncorrected vision of 20/20 J1 or better and 97 per cent 20/25 J2 or better. For hyperopes, 69 per cent achieved 20/20 J1 and 93 per cent 20/25 J2. For myopes, 72 per cent achieved 20/20 J1 and 95 per cent 20/25 J2. Overall, 96 per cent reached 20/25 and 93 per cent 20/20 with 95 per cent reaching J2 or better and 87 per cent J1 or better.

However, eight per cent of myopes, nine per cent of hyperopes and 11 per cent of emmetropes lost one line of best spectacle-corrected vision while one per cent of myopes and emmetropes and two per cent of hyperopes lost two or more lines. About 69 per cent overall had no change in lines of vision while 22 per cent of myopes, 20 per cent of hyperopes and 16 per cent of emmetropes gained one line. One per cent of myopes and two per cent of emmetropes gained two or more lines.

Dr Faure noted that patients who do not achieve 20/25 or spectacle independence for near vision could be retreated.

'Presbyopia and ametropia can be treated successfully providing a high level of patient satisfaction. Histograms prove that the visual outcome is excellent with a good reproducibility. The method can be proposed to all presbyopic patients,' he said.

contact
Jean-Francois Faure – j.f.faure@noos.fr