Circadian IOP Steady After Cataract Surgery With High-Frequency Deep Sclerotomy

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While the combined approach does reduce intraocular pressures, circadian rhythm cannot be changed by the surgery.

Pre- and postoperative analyses indicate that circadian intraocular pressure (IOP) rhythm is not influenced by cataract surgery combined with high frequency deep sclerectomy (HFDS), according to research results published in the Journal of Clinical Medicine. 

In a prospective, open-label study, investigators evaluated IOP fluctuations recorded with SENSIMED Triggerfish® to determine if circadian IOP rhythm might be influenced by combined cataract surgery with HFDS. Additional aims were to determine if IOP can be reduced significantly through HFDS. 

Fluctuations were recorded in 1 eye for 2 full days at 3-month intervals both before and after HFDS plus phacoemulsification in patients with both primary open-angle glaucoma and cataract. Baseline IOP data were collected 1 week prior and 1 to 3 months after surgery. 

Results of previous studies have shown that the Triggerfish contact lens sensor (CLS) provided reproducible data. Measurements were recorded for 30 seconds every 5 minutes for a 24-hour period, providing 288 measurements. 

The study cohort included 10 patients with open-angle glaucoma (50% women; mean age, 68.3±6.43). Preoperative corneal pachymetry central corneal thickness had a mean value of 557±13.5 µm. 

The mean preoperative IOP was 27.7±2.11 mm Hg. After cataract surgery plus HFDS, mean IOP decreased to 14.4±2.59 mm Hg at postoperative month 3, representing a significant decrease. Preoperatively, an average of 3.1±0.99 pressure-reducing drugs were administered to patients; by month 3, no patient required these treatments. This highly significant finding correlated with an average IOP reduction of 13.3 mm Hg or 48%. 

CLS cosinor analysis both pre- and postoperatively of the maximum amplitude of the acrophase in all patients during the sleeping period phase was achieved; minimum amplitude of the bathyphase in the afternoon was also determined. Acrophase was 155.6±76.47 mVeq preoperatively, and 145.7±59.17 mVeq postoperatively. Acrophase was, on average, detected preoperatively at 3 hours 24 minutes, while postoperative detection occurred at 2 hours 32 minutes. 

A similar phenomenon was, according to researchers, observed in the bathyphase with an average amplitude at 15 hours 32 minutes preoperatively.

CLS analysis of the biphasic amplitude of the acrophase preoperative mean was 166.6±74.93 mVeq, while postoperative mean was 172.8±62.53 mVeq, which was not significant. 

Investigators found no statistically significant difference at any time between pre- and postoperative amplitude analysis. “It can be concluded that the surgical treatment…does not change the circadian rhythm,” according to the investigators. 

Study limitations include the small sample size. 

“We found that cataract surgery combined with HFDS achieved a highly significant IOP reduction,” researchers report. “However, it was found that the circadian rhythm measured by CLS is not changed by the surgery compared [with] preoperative analysis. It has also been observed that all patients in both cases, before and after surgery, had the highest IOP during the nocturnal period.” 


Pajic B, Resan M, Pajic-Eggspuehler B, Massa H, Cvejic Z. Triggerfish recording of IOP patterns in combined HFDS minimally invasive glaucoma and cataract surgery: A prospective study. J Clin Med. 2021;10(16):3472. doi:10.3390/jcm10163472