Nasal trabeculo-ciliary angle and relative lens vault as predictors for intraocular pressure reduction following phacoemulsification

Purpose To evaluate quantitative relationships between biometric measurements and expected intraocular pressure reduction following phacoemulsification. Design A prospective, comparative clinical study. Methods Forty nine candidates for phacoemulsification were included. Intraocular pressure was measured preoperatively and after 7 and 30 days. Ocular biometrics were measured using optical biometry and ultrasound biomicroscopy preoperatively and 1 month postoperatively. Results Patients were sub-grouped into open-angle glaucoma (12 eyes), angle-closure glaucoma (18 eyes), and cataract-only groups (19 eyes). The mean intraocular pressure reduction was −1.67 ± 2.73, −13.11 ± 7.98, and −7.50 ± 3.58 mmHg in the cataract-only, angle-closure glaucoma, and open-angle glaucoma groups ( p = 0.001). The delta-intraocular pressure at day 7 showed positive correlations with lens vault and relative-lens vault ( p = 0.005 and 0.001). It showed negative correlations with lens position, relative-lens position, anterior chamber depth, aqueous depth, and nasal and temporal angles in addition to lens thickness, anterior vault, nasal trabeculo-ciliary angle, and temporal-trabeculo-ciliary angle at the end of the follow-up period. Regression analysis revealed significant associations between preoperative intraocular pressure and both nasal-trabeculo-ciliary angle and anterior vault ( p = 0.038 and 0.019) and delta-intraocular pressure and both nasal-trabeculo-ciliary angle and relative-lens vault ( p = 0.001 and ≤0.001) with an area under the curve of 0.71 for relative-lens vault. For every degree decrease in nasal-trabeculo-ciliary angle, there was an expected 0.33 mmHg intraocular pressure reduction with no expected change if nasal-trabeculo-ciliary angle decreased to <22°. Conclusions The relationship between anterior-segment-biometrics could determine intraocular pressure behavior after phacoemulsification. The preoperative nasal-trabeculo-ciliary angle and relative-lens vault could be significant predictors for postoperative intraocular pressure reduction.

Evaluation of the Anterior Chamber Angle by Anterior Segment Optical Coherence Tomography After Implantable Phakic Contact Lens Implantation in Myopic Eyes.

Purpose: To evaluate the changes in the angle of the AC and lens vault after IPCL implantation by AS-OCT in myopic patients.Methods: A prospective observational study involving 30 myopic eyes which were implanted with IPCL with AS-OCT was used for evaluation of the anterior chamber angle parameters as anterior chamber angle (ACA), angle opening distance (AOD) and, trabecular iris space area (TISA) and lens vault at 1,3 and 6 months postoperatively.Results: There were high significant changes between the preoperative values of ACA, AOD and, TISA and first follow-up after 1 month postoperatively with no significant changes between second and third follow-up after 3 and 6 months postoperatively. Regarding the vault, there were stable vault values with no significant changes after 6 months follow-up.Conclusion: IPCL is a safe method of correction of myopia with stable AC angle narrowing which was monitored by the safe noncontact tool, AS-OCT.

Comparison of Phakic Intraocular Lens Vault Using Conventional Nomogram and Prediction Formulas

This study aimed to compare the achieved vault using a manufacturer’s nomogram and the predicted vault using the currently available prediction formulas after posterior chamber phakic intraocular lens (EVO Implantable Collamer Lens; ICL, STAAR Surgical) implantation. We included 200 eyes of 100 consecutive patients (mean age ± standard deviation, 34.3 ± 7.8 years) undergoing ICL implantation with a central hole. Three months postoperatively, we quantitatively measured the actual vault, and we compared it with the predicted vault using anterior segment optical coherence tomography (CASIA 2, Tomey). The agreement rate of the recommended ICL size using the manufacturer’s nomogram, the NK formula, and the KS formula was 50.0%. The achieved vault was 477.1 ± 263.7 µm, which was significantly smaller than the predicted vaults of 551.2 ± 335.1 and 606.4 ± 212.2 µm, using the NK and KS formulas, respectively (Dunnett test, p = 0.014, p < 0.001). The achieved vault was not significantly different from the predicted vault using the NK or KS formula (p = 0.386, p = 0.157) when selecting a 12.1 mm ICL size. It was not significantly different from the predicted vault using the NK formula (p = 0.962), but it was significantly smaller than that using the KS formula (p = 0.033) when selecting a 12.6 mm size. It was significantly smaller than the predicted vault using the NK and KS formulas (p < 0.001) when selecting 13.2 mm size. The total agreement rate of the recommended ICL size was approximately 50%. The predicted ICL vault tended to overestimate the actual ICL vault, especially when selecting a larger ICL size.

Biometry for the Management of Angle Closure in Young patients

Importance: To describe the clinical and biometric features in patients with angle closure presenting before the age of 40 years. Observations: We describe three young patients with angle closure and a customized treatment plan for each guided by the biometric findings, axial length (AL), keratometry, ACD, Lens Thickness, Lens Vault and LT/AL ratio. We found that lens thickness to axial length ratio of >0.2 may suggest the need for clear lens extraction in these cases for better IOP control. Conclusions and relevance: Biometry plays a pivotal role in elucidating the etiopathogenesis and management of angle closure in young patients, and should be included in the evaluation of such patients.