The Effect of Phacoemulsification on Intraocular Pressure in Eyes with Hyperfiltration Following Trabeculectomy: A Prospective Study

[Calculation of intraocular lens power after trabeculectomy]

PURPOSE

To assess biometric changes in eyes after trabeculectomy (TE) and its impact on refractive outcomes of phacoemulsification (PE) in order to determine the corrections for calculation of intraocular lens (IOL) power.

MATERIAL AND METHODS

The study included two groups of patients: the 1^st group consisted of 116 patients who were assessed by optical biometry (IOL-Master 500) for mean biometric values before and after TE; the 2^nd group included 31 patients with history of TE (study subgroup) and 47 individuals without glaucoma (control subgroup) who underwent PE with subsequent comparison of IOL calculation accuracy.

RESULTS

There was significant axial length (AL) shortening in the 1^st group from 23.28±0.97 to 23.19±0.97 mm (p<0.001) 6 months after TE, which positively correlated (r=0.296, p=0.001) with intraocular pressure (IOP) decrease (from 25.4±5.34 to 17.2±4.42 mm Hg, p<0.001). Mean keratometry and anterior chamber depth values did not significantly change after TE. Mean IOL power calculation error after PE in the 2^nd group was -0.05±0.47 D and 0.003±0.62 D for the control and study subgroups, respectively (p=0.697). However, significant impact of preoperative IOP on IOL power calculation error was discovered in the study subgroup (R²=0.526, p<0.001), but not in the control subgroup (R²=0.061, p=0.052). Based on linear regression, the expected IOL power calculation errors depending on the preoperative IOP were determined for patients with history of TE.

CONCLUSION

AL shortening due to decrease in IOP in patients with history of TE leads to IOL power calculation errors. Expected IOL calculation error related to preoperative IOP level was determined, which could help improve refractive outcomes of PE in patients with history of TE.

Phacoemulsification with or without goniosynechialysis for angle-closure glaucoma: a global Meta-analysis based on randomized controlled trials

AIM

To compare the benefits and potential harms of routine phacoemulsification (phaco) alone and combined surgery with goniosynechialysis (GSL) for angle-closure glaucoma (ACG) and coexisting lens opacity, as shown in different randomized controlled trials (RCTs).

METHODS

A systematic review was conducted searching several databases including PubMed, Cochrane Library, EMBASE, ClinicalTrials.gov from the inception to September 2018 for RCTs with data published on the effects and safety of phaco and intraocular lens implantation combined with GSL or routine cataract surgery alone. Several studies were recruited which reported data at baselines and postoperative follow-up, including the mean values of postoperative intraocular pressure (IOP) and mean numbers of anti-glaucoma medications using postoperatively. The numbers of complications happening were also included. Fixed-effect and random-effect models were applied, and the quality of evidence was evaluated.

RESULTS

Analysis of the seven included RCTs, with a total number of 321 participants (358 eyes) diagnosed with ACG and cataract, received a solo procedure (phaco group) or a combined surgery (phaco-GSL group) randomly, and follow-up periods ranging from 2 to 12mo postoperatively. The involved studies showed that the mean value of IOP between the two groups at 3 (four studies, one study follow-up at 2mo postoperative was included), 6, 12mo postoperative were not significantly different. Only two studies reported the change in IOP value at 12mo compared with baseline but showed no significant differences between the two interventions. Although three studies did not have the significant difference in the number of medications using to reduce IOP at 3mo postoperatively, two studies reported that the participants using fewer anti-glaucoma medications at 12mo postoperative in the phaco group than in the phaco-GSL surgery group.

CONCLUSION

The analysis provides a low to moderate-quality evidence that phaco-GSL surgery lead to an equivalent IOP-lowering effect. The phaco-GSL surgery may not help patients to reduce the consumption of anti-glaucoma eyedrops in the long period. The results of this analysis suggested that additional GSL may not be necessary for primary angle closure glaucoma (PACG) patients. Further studies, especially RCTs with more participants and longer follow-up time were needed to provide more sufficient data.