To compare the tear film quantity and stability parameters in keratoconus (KCN) and normal eyes using test breakup time (TBUT), noninvasive TBUT (NITBUT), and Schirmer test.

All participants (n=166), including patients with KCN and age-matched healthy individuals with normal corneas, were recruited from those referred to Farabi Eye Hospital, Iran, in 2023. To better account for genetic and environmental factors, the control group comprised healthy individuals who were relatives of KCN patients and had normal corneal topography. Tear quantity parameters were evaluated in the following order: NITBUT, TBUT, and Schirmer tests.

The mean age of cases in KCN (61.7% males) and normal (63.5% males) participants was 27.54±5.44y (range 19 to 38) and 27.52±5.63y (range 20 to 38), respectively (P=0.976). NIBUT, TBUT, and Schirmer’s tests were significantly lower in KCN group compared to normal controls (all P<0.001). The mean difference for NIBUT was -7.81s (P<0.001), and for TBUT was -7.61s (P<0.001). Schirmer test values were also significantly lower in the KCN group, with a mean difference of -5.61 mm compared to normal people (P<0.001).

Our findings demonstrate significant tear film impairment in KCN. The reductions in NIBUT, TBUT and Schirmer scores highlight an underlying tear film dysfunction in KCN that extends beyond the morphological changes of the cornea.

To compare refractive error and angle of deviation in patients with basic esotropia and basic exotropia.

A retrospective review was conducted on the medical records of patients with basic-type strabismus. Demographic data, refractive error, best-corrected distance visual acuity (BCVA), and the horizontal and vertical angle of deviation between basic esotropia and exotropia patients were compared.

Among the 7129 patients (mean age 22.98±14.81y) evaluated, 44.7% (3185 cases, 54.9% male) exhibited basic-type esotropia, while 55.3% (3944 cases, 53.9% male) presented with basic-type exotropia. Basic esotropia cases exhibited more hyperopic spherical equivalent measurements in both eyes (right: 0.53±3.07 vs left: 0.56±2.98 D) than those with basic exotropia (right eye: -0.33±2.84 vs left eye: -0.24±2.68 D, P<0.001 for both eyes). Patients with basic esotropia had significantly greater horizontal deviation angles (near: 36.08±18.87 PD and far: 35.56±18.75 PD) compared to those with basic exotropia (near: 33.75±16.11 PD and far: 33.26±15.90 PD, P<0.001). Conversely, patients with basic exotropia had slightly higher vertical deviation angles (near: 1.67±5.80 PD and far: 1.72±5.89 PD) compared to those with basic esotropia (near: 1.12±4.57 PD and far: 1.12±4.58 PD, P<0.001). Patients with basic esotropia underwent surgical intervention at younger ages compared to basic exotropia individuals (19.68±15.99 vs 25.66±13.20, P<0.001).

Basic esotropia patients present more hyperopic refractive errors, better visual acuity, larger horizontal yet smaller vertical ocular misalignments, and tend to undergo strabismus surgery at younger ages relative to basic exotropia cases.