Low Luminance Questionnaire Linked to Functional Measures of AMD

Atalie Thompson, MD, MPH

Low Luminance Questionnaire (LLQ) scores were significantly associated with computerized low luminance visual acuity (LLVA) and low luminance deficit (LLD) in patients with early/intermediate age-related macular degeneration (AMD), according to results of a recent study.

The cross-sectional study examined patients with early and intermediate AMD, compared with controls. Participants were given the LLQ, along with tests for best-corrected visual acuity (BCVA), mesopic microperimetry, dark adaptometry (DA), low luminance visual acuity (LLVA), and cone contrast test (CCT).

“It is important to determine accurate and patient-centered ways of assessing visual impairment in early and intermediate dry AMD,” lead author Atalie C. Thompson, MD, MPH, of the Duke University Department of Ophthalmology, Durham, North Carolina, told MD Magazine. “We would like to be able to more effectively screen for the disease and we would like to be able to therapeutically intervene at earlier stages of the disease before irreparable damage has been done to the retina. We know that early on, patients with AMD begin to suffer impaired visual function in low lighting settings well before they experience the profound central vision loss that occurs at advanced stages of the disease process.”

Thompson and colleagues defined LLD as the difference in the number of letters read under photopic versus low luminance settings. They used linear regression to determine the association of LLQ with visual function test scores linear regression.

“Among patients with early and intermediate AMD, we found that scores on the 32-item LLQ were significantly associated with computerized tests for LLVA and LLD,” Thompson said.

The published results indicated that the patients with intermediate AMD had significantly lower LLQ composite scores (mean, 75.8 ±16.7; median, 76; range, 29-97) when compared to those with early AMD (mean, 85.3 ±13.3; median, 88; range, 50-100; P = .007) or the control group (mean, 91.4 ±6.5; median, 94; range, 79-99; P <.001) in the overall cohort.

LLQ composite scores were found to be linked with computerized BCVA (β = 0.516), and computerized LLVA at 2 background luminance (1.3 cd/m², β = 0.660; 0.5 cd/m², β = 0.489). Additionally, their respective computerized LLDs (β = -0.531 and -0.467), rod intercept (β = -0.312), and CCT green (β = 0.183) (all P <.05) were all associated with LLQ composites.

“Only the computerized LLVAs and computerized LLDs remained statistically significant after adjusting for AMD versus control status (P <.05). Among AMD subjects, LLQ composite scores were significantly associated with the computerized LLVAs (β = 0.622 and 0.441) and LLDs (β = -0.795 and -0.477) at both the 1.3 and 0.5 cd/m2 luminance levels, respectively, and these associations remained significant after adjusting for AMD severity (P < 0.05),” the authors wrote.

“These particular computerized tests of low luminance vision may better reflect the patient experience of visual dysfunction in low lighting settings than their non-computerized correlates,” Thompson said. “Both the LLQ and computerized tests of LLVA and deficit may be useful functional outcomes for current and future therapeutic clinical trials for early and intermediate AMD.”

The study, “Association of Low Luminance Questionnaire With Objective Functional Measures in Early and Intermediate Age-Related Macular Degeneration,” was published in Investigative Ophthalmology & Visual Science.

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