Do high blood pressure, lens status, fundus examination, and eye laterality affect mean subfoveal choroidal thickness measurements?

Impact of Blood Pressure, Lens Status, Fundus Findings, and Eye Laterality on Subfoveal Choroidal Thickness

The statement is partially incorrect: while systemic hypertension (blood pressure alone) does not significantly affect subfoveal choroidal thickness, the presence of hypertensive retinopathy on fundus examination does cause significant changes in choroidal thickness measurements.

Blood Pressure Effects

Systemic Hypertension vs. Hypertensive Retinopathy

The critical distinction lies between systemic blood pressure measurements and actual retinal disease manifestations:

• Systemic blood pressure values (diastolic or systolic readings) do not significantly correlate with subfoveal choroidal thickness 1
• In a large population study of 3,237 subjects, neither diastolic blood pressure (P = 0.94), history of hypertension (P = 0.95), nor duration of hypertension (P = 0.91) showed significant associations with choroidal thickness 1
• However, when hypertensive retinopathy is present on fundus examination, subfoveal choroidal thickness increases significantly (286.48 ± 105.23 µm with retinopathy vs. 187.04 ± 78.80 µm without, P < 0.001) 1

Severity-Dependent Changes

• Subfoveal choroidal thickness correlates significantly with the stage of hypertensive retinopathy (P < 0.001), not with blood pressure numbers themselves 1
• In severe hypertension (SBP ≥180 or DBP ≥110 mmHg), exudative choroidal changes occur with increased subfoveal choroidal thickness, but these resolve rapidly with blood pressure control 2
• After multivariate adjustment in myopic patients, systolic blood pressure was not a significant factor for maculopathy, though it appeared significant in univariate analysis 3

Fundus Examination Findings

Fundus examination findings are the most critical factor affecting subfoveal choroidal thickness measurements among the variables mentioned:

• The presence of hypertensive retinopathy lesions on fundoscopy indicates actual choroidal involvement and significantly thicker measurements 1
• Fundus features in severe hypertension (macular edema, subretinal fluid, nerve fiber layer thickening) correlate with both baseline and final visual acuity 2
• Choroidal lesions during chronic hypertension play an important role in hypertensive retinopathy development 1

Clinical Pitfalls

Common Measurement Errors

• Measurement variability increases substantially with thicker choroids: in eyes with pathologically thick choroids (like central serous chorioretinopathy), interobserver coefficients of repeatability reach 46-57 μm compared to 26-35 μm in normal eyes 4
• Intraocular pressure changes can acutely affect choroidal thickness measurements (30.0 ± 36.8 μm decrease with IOP increase, P < 0.001), which could confound readings 5

Interpretation Guidelines

• Do not rely on blood pressure readings alone to predict choroidal thickness changes 1, 3
• Always correlate with actual fundoscopic findings of hypertensive retinopathy 1
• Consider that acute IOP elevations cause choroid thinning (r = -0.71 with IOP change, P < 0.001), which may mask other pathology 5

Regarding Lens Status and Eye Laterality

The provided evidence does not address lens status (phakic vs. pseudophakic) or eye laterality (right vs. left eye) effects on subfoveal choroidal thickness measurements. Based on the exclusion of these factors from major population studies and the lack of discussion in the literature provided, these variables likely have minimal clinical significance for choroidal thickness measurements in routine practice.