Cataracts: 20/40 or Better Visual Acuity within 90 Days Following Cataract Surgery

In the United States, cataracts affect more than 24 million adults over 40 years (National Eye Institute, 2019). According to the American Academy of Ophthalmology (2021), cataract surgery has a substantial beneficial impact on visual function and on quality of life.

1. Scientific basis for measuring visual acuity outcomes after cataract surgery

The only reason to perform cataract surgery (other than for a limited set of medical indications) is to improve a patient's vision and associated functioning. The use of a 20/40 visual acuity threshold is based on several considerations. First, it is the level for unrestricted operation of a motor vehicle in the US. Second, it has been consistently used by the FDA in its assessment for approval of intraocular lens (IOL) and other vision devices. Third, it is the literature standard to denote success in cataract surgery. Fourth, work by West et al. in the Salisbury Eye Study suggests that 20/40 is a useful threshold for 50th percentile functioning for several vision-related tasks.

Most patients achieve excellent visual acuity after cataract surgery (20/40 or better). This outcome is achieved consistently through careful attention through the accurate measurement of axial length and corneal power and the appropriate selection of an IOL power calculation formula. As such, it reflects the care and diligence with which the surgery is assessed, planned and executed. Failure to achieve this after surgery in eyes without comorbid ocular conditions that would impact the success of the surgery would reflect care that should be assessed for opportunities for improvement.

The exclusion of patients with other ocular and systemic conditions known to increase the risk of an adverse outcome reflects the findings of the two published prediction rule papers for cataract surgery outcomes, by Mangione et al. (1995) and Steinberg et al. (1994). In both papers, the presence of comorbid glaucoma and macular degeneration negatively impacted the likelihood of successful outcomes of surgery. Further, as noted in the prior indicator, exclusion of eyes with ocular conditions that could impact the success of the surgery would NOT eliminate the large majority of eyes undergoing surgery while also minimizing the potential adverse selection that might otherwise occur relative to those patients with the most complex situations who might benefit the most from having surgery to maximize their remaining vision.

2. Evidence of a gap in care

Cataract surgery successfully restores vision in the majority of people who have the procedure.

Data from a study of 368,256 cataract surgeries show that corrected visual acuity (CDVA) of 0.5 (20/40) or better was achieved in 94.3% and CDVA of 1.0 (20/20) or better was achieved in 61.3% of cases (Lundstrom, Barry, Henry, Rosen & Stenevi, 2013).

Additionally, data from a UK multi-center Cataract National Dataset found a postoperative visual acuity of 6/12 (20/40) or better was achieved for 94.7% of eyes with no co-pathologies and in 79.9% of eyes with one or more co-pathologies (Jaycock et al., 2009).

A rate of 85.5-94.7% of patients achieving a 20/40 or better visual acuity in the context of approximately 3 million cataract surgeries in the US annually would mean that between 160,000 to 435,000 individuals would not achieve a 20/40 or better visual acuity which suggests an opportunity for improvement.

In the United States, cataracts affect more than 24 million adults over 40 years (National Eye Institute, 2019). According to (Miller et al., 2022), cataract surgery has a substantial beneficial impact on visual function and on quality of life.

1. Scientific basis for measuring visual acuity outcomes after cataract surgery

The only reason to perform cataract surgery (other than for a limited set of medical indications) is to improve a patient's vision and associated functioning. The use of a 20/40 visual acuity threshold is based on several considerations. First, it is the level for unrestricted operation of a motor vehicle in the US. Second, it has been consistently used by the Food and Drug Administration in its assessment for approval of intraocular lens (IOL) and other vision devices. Third, it is the literature standard to denote success in cataract surgery. Fourth, work by West et al. in the Salisbury Eye Study suggests that 20/40 is a useful threshold for 50th percentile functioning for several vision-related tasks.

Most patients achieve excellent visual acuity after cataract surgery (20/40 or better). This outcome is achieved consistently through careful attention through the accurate measurement of axial length and corneal power and the appropriate selection of an IOL power calculation formula. As such, it reflects the care and diligence with which the surgery is assessed, planned and executed. Failure to achieve this after surgery in eyes without comorbid ocular conditions that would impact the success of the surgery would reflect care that should be assessed for opportunities for improvement.

The exclusion of patients with other ocular and systemic conditions known to increase the risk of an adverse outcome reflects the findings of the two published prediction rule papers for cataract surgery outcomes, by Mangione et al. (1995) and Steinberg et al. (1994). In both papers, the presence of comorbid glaucoma and macular degeneration negatively impacted the likelihood of successful outcomes of surgery. Further, as noted in the prior indicator, exclusion of eyes with ocular conditions that could impact the success of the surgery would NOT eliminate the large majority of eyes undergoing surgery while also minimizing the potential adverse selection that might otherwise occur relative to those patients with the most complex situations who might benefit the most from having surgery to maximize their remaining vision.

2. Evidence of a gap in care

Cataract surgery successfully restores vision in the majority of people who have the procedure.

Data from a study of 368,256 cataract surgeries show that corrected visual acuity (CDVA) of 0.5 (20/40) or better was achieved in 94.3% and CDVA of 1.0 (20/20) or better was achieved in 61.3% of cases (Lundstrom et al., 2013).

Additionally, data from a UK multi-center Cataract National Dataset found a postoperative visual acuity of 6/12 (20/40) or better was achieved for 94.7% of eyes with no co-pathologies and in 79.9% of eyes with one or more co-pathologies (Jaycock et al., 2009).

A rate of 85.5-94.7% of patients achieving a 20/40 or better visual acuity in the context of approximately 3 million cataract surgeries in the US annually would mean that between 160,000 to 435,000 individuals would not achieve a 20/40 or better visual acuity which suggests an opportunity for improvement.