Screening for CMV retinitis using chromatic discrimination thresholds and achromatic contrast sensitivity

Area of Science:

• Ophthalmology
• Virology
• Immunology

Background:

• Cytomegalovirus retinitis (CMVR) often presents asymptomatically in HIV+ patients with low CD4 counts.
• Effective screening tests for early CMVR detection are crucial for timely intervention.
• Current retinal function tests have limited efficacy in identifying CMVR.

Purpose of the Study:

• To evaluate chromatic discrimination thresholds and achromatic contrast sensitivity as potential screening tools for CMVR in HIV+ individuals.
• To compare the visual function of HIV+ patients with CMVR to HIV+ patients without CMVR and healthy controls.

Main Methods:

• Recruited 11 HIV+ patients with CMVR, 16 HIV+ patients without CMVR, and 29 age-matched controls.
• Measured visual acuity, chromatic discrimination thresholds, and achromatic contrast sensitivity.
• Performed fundal examination via slit lamp biomicroscopy and graded CMVR from photographs.

Main Results:

• Patients with CMVR showed significant loss in tritan (p<0.0005) and red/green (p<0.05) chromatic discrimination.
• Achromatic contrast sensitivity was reduced in CMVR patients at spatial frequencies of 2.2, 3.4, and 10 cpd (p<0.05).
• No significant differences were observed between HIV+ patients and controls for any tested visual function (p>0.1).

Conclusions:

• HIV+ patients diagnosed with CMVR exhibit impaired chromatic discrimination and achromatic contrast sensitivity.
• These visual function deficits suggest that chromatic and achromatic tests can serve as effective screening methods for CMVR in HIV+ individuals.