Ultrashort-pulse lasers treating the crystalline lens: will they cause vision-threatening cataract? (An American Ophthalmological Society thesis)

• Published in: Transactions of the American Ophthalmological Society 2012-12, Vol.110, p.130-165
• Main Authors: Krueger, Ronald R, Uy, Harvey, McDonald, Jared, Edwards, Keith
• Format: Article
• Language: English
• Subjects: Adult; Animals; Cataract - etiology; Cataract - prevention & control; Female; Humans; Laser Therapy - adverse effects; Laser Therapy - methods; Lens, Crystalline - radiation effects; Macaca mulatta; Male; Middle Aged; Models, Animal; Presbyopia - therapy; Prospective Studies; Vanadates - therapeutic use; Visual Acuity
• ISSN: 0065-9533; 1545-6110

To demonstrate that ultrashort-pulse laser treatment in the crystalline lens does not form a focal, progressive, or vision-threatening cataract. An Nd:vanadate picosecond laser (10 ps) with prototype delivery system was used. Primates: 11 rhesus monkey eyes were prospectively treated at the University of Wisconsin (energy 25-45 μJ/pulse and 2.0-11.3M pulses per lens). Analysis of lens clarity and fundus imaging was assessed postoperatively for up to 4½ years (5 eyes). Humans: 80 presbyopic patients were prospectively treated in one eye at the Asian Eye Institute in the Philippines (energy 10 μJ/pulse and 0.45-1.45M pulses per lens). Analysis of lens clarity, best-corrected visual acuity, and subjective symptoms was performed at 1 month, prior to elective lens extraction. Bubbles were immediately seen, with resolution within the first 24 to 48 hours. Afterwards, the laser pattern could be seen with faint, noncoalescing, pinpoint micro-opacities in both primate and human eyes. In primates, long-term follow-up at 4½ years showed no focal or progressive cataract, except in 2 eyes with preexisting cataract. In humans, 70% reported acceptable or better distance vision and no or mild symptoms. Meanwhile, >70% without sparing (0 and 0.5 mm radius) lost 2 or more lines, and most reported poor or severe vision and symptoms. Focal, progressive, and vision-threatening cataracts can be avoided by lowering the laser energy, avoiding prior cataract, and sparing the center of the lens.