Cataract surgery is a common procedure, and the decision to operate is typically made for each eye independently. A cataract is the clouding of the eye’s naturally clear lens, which scatters light and impairs vision. While the condition often develops in both eyes (bilateral cataracts), the clouding often progresses at different rates. This means one eye may require surgery long before the other, focusing the treatment plan on the functional status of each eye.
Determining the Need for Surgery in Each Eye
The presence of a cataract alone does not necessitate surgery; the primary factor is the degree to which visual impairment affects a person’s daily life. Doctors evaluate the need using specific measures of functional vision.
One common metric is the best-corrected visual acuity (BCVA); a measurement of 20/40 or worse is often used as a threshold by surgeons and insurance carriers, as this is frequently the minimum required for driving. The decision extends beyond a single number, focusing heavily on a patient’s reported difficulty with everyday activities.
The inability to comfortably read or perform occupational tasks due to hazy or blurred vision is a strong indication for surgery. Glare sensitivity and poor contrast perception are also significant factors, as cataracts can cause headlights or bright sun to create halos or starbursts, even if standard visual acuity remains relatively good.
Understanding Sequential Surgery
For patients requiring surgery in both eyes, the standard protocol is delayed sequential bilateral cataract surgery (DSBCS). This approach involves operating on the first eye and scheduling the second procedure after a planned waiting period, typically between one and four weeks.
The delay allows the first eye to heal and stabilize before operating on the second. This waiting period is used to assess the refractive outcome of the first procedure and fine-tune the intraocular lens power calculation for the second eye.
The delay also reduces the risk of a simultaneous, sight-threatening complication, such as severe bilateral infection (endophthalmitis). Treating the eyes as two distinct surgical events eliminates the risk of contaminated fluid or medication affecting both eyes.
Immediate Sequential Bilateral Cataract Surgery
A less common alternative is Immediate Sequential Bilateral Cataract Surgery (ISBCS), where both eyes are operated on during the same session. This procedure is not the standard of care but is considered for specific circumstances.
Candidates often face significant logistical challenges, such as difficulty traveling long distances, or have a high medical risk under anesthesia, as ISBCS limits them to a single hospital visit.
To mitigate risks, ISBCS requires strict precautions, treating the second eye as if it belongs to a different patient entirely. This includes using completely separate surgical instruments, gloves, drapes, and batches of fluids for each eye.
Although the risk of bilateral infection is minuscule when these protocols are followed, the potential for a simultaneous complication or a shared refractive error means that DSBCS remains the preferred option for most people.