Factors affecting conjunctivochalasis, tear meniscus area
Meibomian gland dysfunction (MGD) is associated with lower tear meniscus area (TMA), while older age corresponds to a more severe conjunctivochalasis, a recent Singapore study has shown. This suggests that anterior segment optical coherence tomography (ASOCT) may be useful in assessing ocular surface tear function and tear volume.
The researchers performed ASOCT imaging on 403 adults (mean age 59.7±7.8 years; 52.9 percent female) recruited from the Singapore Indian Eye Study. Measurements of the inferior tear meniscus at three ocular regions (nasal, central and temporal) were used to determine the TMA and conjunctivochalasis ratio (CCR).
TMA in the central ocular scan was significantly lower in patients with MGD vs those without (1,656±1,069 vs 1,914±1,222 pixel2; p=0.048) even after excluding outliers. Females also showed significantly lower TMA than males (p=0.031). [Ophthalmic Epidemiol 2018;25:70-78]
Logistic regression analysis adjusted for age, sex, dry eye symptoms and meibomitis likewise showed a significant correlation between the female sex (adjusted odds ratio [OR], 1.57; 95 percent CI, 1.05–2.34) and having MGD (adjusted OR, 1.55; 1.02–2.38) and lower TMA.
The interaction between the female age and TMA may possibly be explained by a drop in sex hormone levels in postmenopausal women, which has been associated with drier eyes, shorter tear break-up time and lower tear volume, researchers explained. [Eye 2010;24:79-83; Ophthalmic Physiol Opt 2008;28:365-372]
Notably, high TMA was not significantly more common in those with ≥3 dry eye symptoms (38.5 percent vs 61.5 percent; p=0.134), indicating no significant relationship between dry eye and TMA. This was confirmed in logistic regression analysis (adjusted OR, 0.59; 0.30–1.17).
The above finding is in conflict with previous studies, which report either significantly higher or smaller TMA in association with dry eye. Differences in information collection and measurement protocols may have resulted in the discrepancies, the researchers said.
“We have adjusted for dry eye symptoms in our analysis despite them not being significantly associated with TMA. This is because of the close association of pathophysiology of dry eye with tears, whether a deficiency in production or increased evaporation of tears,” noted researchers.
Severe conjunctivochalasis (CCR>0.7) was reported in 9.2 percent of the cohort; 39 percent had mild to no conjunctivochalasis. Stratifying participants by age showed that severe conjunctivochalasis was significantly more common in those aged ≥60 vs <60 years (15.8 percent vs 3.6 percent; p<0.001).
Fully-adjusted logistic regression confirmed the significant correlation between increasing age and higher conjunctivochalasis severity (adjusted OR, 5.00; 2.21–11.31).
The mean CCRs from the nasal, temporal and central scans were 0.641, 0.730 and 0.393, respectively, which suggested that CCR severity would appear greatest when measured from the temporal images.
“This study has shed new light on the population characteristics and associations of tear meniscus and conjunctivochalasis and has provided a better understanding on the prevalence of low tear meniscus and conjunctivochalasis in the population,” said researchers.
“For future studies, we recommend extending this study to other races and correlating ASOCT grading of conjunctivochalasis with clinical tear function tests such as Schirmer’s test, TBUT, ocular surface staining and tear osmolarity,” they added.