3081: very high myopia in a younger patient
This is a complete cataract case performed by Uday Devgan MD. You can see the full series of these here: https://cataractcoach.com/category/complete-cases/
Cataract surgery in highly myopic eyes presents a distinct set of challenges that require careful planning, surgical technique adjustment, and close post-operative management. When the axial length exceeds 26 millimeters, the structural mechanics of the eye change completely: we are working with a deeper anterior chamber, a larger capsular bag, thinner sclera, potentially weaker zonules, and a vulnerable posterior segment. Operating on these long eyes as if they were standard routine cases can lead to intraoperative surprises such as lens-iris diaphragm retropulsion syndrome, capsular rupture, or post-operative retinal complications.
Managing a high myope begins long before stepping into the operating room. Setting expectations regarding post-operative refraction is critical because these patients are accustomed to a very specific visual environment. Consider a pre-operative minus ten diopter myope who has a focal point without glasses at just ten centimeters from the eye. They are used to holding objects right up to their face to inspect fine details with high microscopic magnification. Once you perform cataract surgery and aim for distance or mild myopia, that extreme near focal point is permanently lost. You must educate these patients before surgery about this optical change, explaining that while they will gain superior uncorrected distance vision, they will lose their built-in near point and will require reading glasses for close work.
For intraocular lens power calculation, selection of the appropriate formula is essential. Traditional formulas often underestimate IOL power in long eyes, leading to a hyperopic surprise. Modern formulas specifically optimized for long axial lengths, such as Barrett Universal II, are preferred. Always err on the side of slight residual myopia, rather than targeting absolute plano. Patients will tolerate mild residual myopia far better than an unexpected hyperopic outcome. Furthermore, detailed evaluation of the retina is mandatory during the initial consultation because high myopes have a significantly higher incidence of peripheral retinal pathology like lattice degeneration, retinal tears, and staphylomas. Perform a thorough dilated peripheral retinal exam, and if you identify suspicious lesions or have any doubts about retinal stability, obtain a prompt retina consultation from a colleague prior to scheduling surgery.
In highly myopic eyes, the anterior chamber is exceptionally deep and the anterior capsule can be thinner. The dilated pupil may look huge, which distorts visual estimation of sizing. Aim for a centered continuous curvilinear capsulorhexis measuring 5.0 to 5.5 millimeters in diameter (Figure 1). A rhexis that is too small risks capsular phimosis later due to weak zonular counter-traction, while a rhexis that is too large may fail to cover the optic edge completely, leading to decentralization or anterior capsule wrap issues. Hydro-dissection must be performed gently to avoid building excessive fluid pressure behind the nucleus, which could stress the fragile zonules or posterior capsule.
Lens-iris diaphragm retropulsion syndrome (LIDRS) occurs when fluidic pressure in the anterior chamber is higher than in the posterior chamber, driving the iris-lens diaphragm backward and creating a massive expansion of the anterior chamber. The iris flattens, the pupil dilates further, and the chamber becomes extraordinarily deep, making reach and instrument manipulation difficult. Patients may also feel a high degree of pressure and pain when this happens. Equalize chamber pressures by lifting the iris edge gently with a second instrument to break the fluid seal between the iris and the lens capsule, allowing fluidic pressures to equalize which will return the chamber depth to normal.
The zonular apparatus and posterior capsule in high myopes require exceptionally gentle handling. Due to the deep chamber and sometimes lax capsular bag support, high vacuum and aggressive nuclear manipulation can place dangerous stress on the posterior capsule. Bring the nucleus or nuclear halves gently out of the capsular bag into the supra-capsular space or anterior chamber iris plane can help tremendously (Figure 2). Operating slightly higher in the chamber reduces proximity to a deep, sagging posterior capsule, minimizing the risk of posterior capsule rupture. When implanting the foldable intraocular lens, verify complete deployment within the capsular bag and ensure both haptics are fully unfolded inside the bag equator, centered under your capsulorhexis.
Post-operative care in high axial myopes requires extended vigilance across multiple fronts. High myopes are more susceptible to early post-operative intraocular pressure spikes, making complete removal of viscoelastic from behind the lens and out of the angle vital. Monitor intraocular pressure early in the post-operative period. Additionally, instruct the patient to watch for signs of posterior vitreous detachment progression, new floaters, flashes of light, or visual field loss, as shifting vitreous dynamics after cataract removal can exert traction on areas of retinal weakness. Continue monitoring the retina at follow-up visits, maintaining a low threshold for retina subspecialist re-evaluation if any concerns arise. For our highly myopic patients who have suffered from poor vision for nearly the entirety of their lives, refractive cataract surgery can truly transform the way they see the world. We can address the myopia and the astigmatism with a toric IOL (Figure 3). For these patients who have dreamt of great vision without the burden of glasses and contact lenses, we can give them the gift of sight.
