A new look at risk factors for cataractogenesis in laser corneal refractive surgery

Purpose: To examine cataractogenic risk factors in corneal laser refractive surgery and propose a scoring system for them. Patient and Methods: Literature data on cataract development after corneal refractive surgery were analyzed. Our own clinical material covers 20 years of clinical observations of the long-term results of various keratorefractive surgeries with an emphasis on the state of the lens and the development of cataracts in periods from 5 to 20 years or more after laser refractive surgeries on the cornea (PRK, TransPRK, LASIK, FemtoLASIK, SMIL). Results: Literature analysis showed that after corneal laser refractive surgery, cataracts appear to be younger by an average of 10 years. The main risk factors for cataractogenesis included corneal thinning, a high degree of initial ametropia, residual lower-order aberrations, induced higher-order aberrations, patient age, accommodative disorders, and presbyopia. Clinical observations have shown that laser correction of high ametropia significantly increases the risk of cataractogenesis. This is due to the larger volume of stromal tissue removed, a more pronounced aseptic inflammatory response with the accumulation of peroxide radicals and oxidative stress in all structures of the anterior segment of the eye. Late after refractive surgery, the photoprotective function of the thinned cornea weakens, increasing UV stress on the lens, which is one of the important factors initiating cataractogenesis and the earlier development of cataracts. Conclusion: For clinically significant early development of cataracts after laser refractive surgery on the cornea, a combination of several cataractogenic factors is necessary, such as the degree of corneal thinning, the magnitude of ametropia, the severity of the aseptic inflammatory reaction in the tissues of the anterior segment of the eye in the early postoperative period, induced higher-order aberrations, residual lower-order aberrations, weakness of accommodation and the development of presbyopia.