Comparison in lens thickness and anterior chamber of early and intumescent stages of cataract by CASIA SS-1000 anterior segment optical coherence tomography

Background

With the progression of cortical cataract, the lens thickness and anterior chamber will change and may have significant influences on the structure and function of the eyes.A special measurement is needed to observe the anterior and posterior surface of lens and detailed angle structure, and to quantify these changes.

Objective

This study was to compare the lens thickness and angle structures by CASIA SS-1000 anterior segment optical coherence tomography (AS-OCT) in early and intumescent stage of cataract and quantify the ocular anatomical differences.

Methods

An observational study was performed.Fifty cortical cataract patients (87 eyes) of the early stage or the intumescent stage in the ophthalmology outpatient clinic of Daping Hospital from October 16 to October 30, 2015 were continuously enrolled in this research.The eyes were assigned to the early stage group (28 patients 44 eyes) and the intumescent stage group (22 patients 43 eyes) according to the slit lamp examination results.The average age was (56.46±12.90) years in the early stage group and (70.95±8.81) years in the intumescent stage group.With the use of CASIA SS-1000 AS-OCT measurements, lens thickness, angle opening distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA), trabecular-iris angle (TIA) and anterior chamber depth (ACD) were measured and compared between the two groups.

Results

Lens thickness was (4.438±0.487)mm in the early stage group and (5.094±0.451)mm in the intumescent stage group, with an average increase of (0.656±0.101)mm, showing a significant difference between the two groups (t=-6.513, P=0.000). ACD in the early stage group was (2.966±0.326)mm and (2.534±0.376)mm in the intumescent stage group, with an average decrease of (0.432±0.075)mm, showing a significant difference between the two groups (t=5.730, P=0.000). AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500 and TIA750 were all lower in the intumescent stage group than those in the early stage group, with significant differences between the two groups (all at P=0.000).

Conclusions

The lens was thicker, ACD was shallower and anterior angle was narrower in the intumescent stage than those in the early stage of cortical cataract patients.SS-1000 AS-OCT is efficiency with high definition, and is supposed to have promising prospect of clinical application.