Abstract
Purpose :
to compare anterior chamber volume (ACV) variation and iridocorneal angle increase on vertical (90°-270°) and horizontal (0-180°) meridian after laser peripheral iridotomy LPI in two groups of primary angle-closure suspects (PACS) eyes, respectively with ACV lower or equal to 74 mm3 (Group 1), and eyes with ACV lower than 99 mm3 but higher than 75 mm3 (Group 2), through a Scheimpflug camera analysis.
Methods :
49 eyes classified as PACS according to Scheimpflug camera risks criteria as reported in literature, were enrolled in this study and divided in two groups according to ACV volume as mentioned above. Every eye received two Yag-laser LPI in the superior quadrant. Scheimpflug camera analysis was performed before LPI and repeated 15 days after treatment. ACV, anterior chamber depth (ACD), anterior chamber angle (ACA) and pachimetry measurements both on horizontal and vertical meridian were collected and a statistical analysis was performed. Only examinations with a Pentacam Quality Score QS=[ok] were accepted.
Results :
Mean ACV increased from 64.96±6.81 to 85.68±10.65 mm3 in Group 1, and from 88.08±8.73 to 108.21±12.84 mm3 in Group 2. Mean ACD varied from 1.80±0.13 to 1.82±0.12 mm in Group 1 and from 2.13±0.17 to 2.16±0.19 mm in Group 2. Mean ACA0-180° increased from 18.33±3.92 to 20.86 ±3.93 degrees in Group 1 and from 25.29±4.26 to 26.13±4.25 degrees in Group 2. Mean ACA90-270° increased from 16.88±3.26 to 17.31±2.53 degrees and from 21.25±3.44 to 21.44±3.81 degrees in Group 2.
Conclusions :
As expected from previous literature data, statistically significant differences in the two groups were found in terms of ACV and ACA increase after LPI. Moreover, statistically significant differences (p<0.05) in terms of ACV and ACA 0-180° percentage increase (p=0.032, p=0.004) were found in Group 1 compared to Group 2. No statistically significant difference (p>0.05) was found between the two groups in terms of ACA increase on vertical 90-270° meridian, ACD and pachimetry. In the last few years, several studies suggested Scheimpflug camera parameters as risk criteria for primary angle closure; besides confirming an important role of Scheimpflug camera in the assessment of primary angle closure risk, our study seems to strengthen the evidence of a higher risk for those patients with initial anterior chamber estimated volume lower than 75 mm3.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.