A comparison of lens parameters in patients with various subtypes of primary angle-closure disease and the normal population: A prospective study

Purpose: To assess the role of lens parameters in the detection and progression of primary angle-closure disease (PACD) by combining A-scan and A-scan optical coherence tomography (AS-OCT) parameters. Methods: A cross-sectional study was conducted in a tertiary health-care center in eastern India. A total of 91 study subjects including cases and controls were included in the study. The parameters studied were lens thickness (LT), lens axial factor (LAF), relative lens position (RLP), and lens vault (LV). Anterior chamber depth (ACD) and axial length (AL) were also analyzed using A-scan. Results: The LT was significantly more in all subtypes of PACD (from 4.24 ± 0.84 to 5.02 ± 0.18 mm) than in controls (4.04 ± 0.46 mm; P < 0.01). Similarly, LAF was significantly less among all subtypes of PACD compared to controls (P < 0.001). The RLP, calculated using the formula (ACD + 0.5 LT)/AL × 10, showed no significant difference (P > 0.05) between various study groups. The LV in acute angle-closure glaucoma (AcCG) patients was significantly higher compared to the control population (P < 0.01). Ocular parameters like ACD decreased, whereas LT and LAF increased from normal through primary angle closure (PAC) to primary angle-closure glaucoma (PACG). Logistic regression analysis found a significant association between a decrease in ACD and an increased risk of PACG (P-value was 0.0001) and an increase in LT and LAF with increased risk of PACG (P = 0.040 and P = 0.006, respectively). Conclusion: Inclusion of lens parameter assessment in the workup of a patient with PACD helps in detection and close monitoring of the progression from suspected to disease state.

Effects of Choroidal Thickness on Refractive Outcome Following Cataract Surgery in Primary Angle Closure

PURPOSE: To identify the preoperative biometric factors, including subfoveal choroidal thickness (CT), associated with refractive outcome after cataract surgery in eyes with primary angle closure (PAC). METHODS: This study included 50 eyes of 50 PAC patients who underwent uneventful cataract surgery. Preoperatively, anterior segment parameters including anterior chamber depth (ACD) and lens vault were determined by anterior segment optical coherence tomography. Subfoveal CT was measured by spectral domain optical coherence tomography enhanced depth imaging before and at one month after surgery. Mean refractive error (MRE) was calculated as the difference in spherical equivalent between actual postoperative refraction determined one month postoperatively and that predicted using each of three IOL calculation formulas (SRK/II, SRK/T, and Haigis). Regression analyses were performed to investigate potential associations between MRE and putative factors. RESULTS: Mean ACD was 1.9 ± 0.4 mm, and preoperative subfoveal CT was 250.8 ± 56.9 µm. The SRK/T (MRE, 0.199 ± 0.567 diopters [D]) and Haigis (MRE, 0.190 ± 0.727 D) formulas showed slight hyperopic shift, while the SRK/II formula demonstrated a myopic shift (MRE, −0.077 ± 0.623 D) compared with that expected after cataract surgery. Mean absolute refractive error was not significantly different between formulas. Higher preoperative lens vault and shallower ACD were associated with a hyperopic shift in all formulas, but not in a statistically significant manner. Thicker preoperative subfoveal choroid was associated with a myopic shift after cataract surgery in all formulas (SRK/II: β = −0.511, p < 0.001; SRK/T: β = −0.652, p < 0.001; Haigis: β = −0.671, p < 0.001). Greater postoperative reduction of subfoveal CT was associated with a myopic shift after cataract surgery in all formulas (SRK/II: β = −0.511, p < 0.001; SRK/T: β = −0.652, p < 0.001; Haigis: β = −0.671, p < 0.001). CONCLUSIONS: Our results indicate that preoperative subfoveal CT and the difference between pre- and postoperative subfoveal CT are significant factors for predicting refractive error after cataract surgery in PAC patients. These findings should be considered when performing cataract surgery to optimize visual outcomes.

Iris-trabecular Contact Index Change after Cataract Surgery in Acute Angle Closure Glaucoma

PURPOSE: To evaluate the change of iris-trabecular contact index (ITC index) after cataract surgery in acute angle closure glaucoma. METHODS: Twelve patients (17 eyes) who had a history of acute angle closure glaucoma underwent swept source optical coherence tomography before and after cataract surgery. Correlations between lens vault (LV), ITC index and intraocular pressure (IOP), anterior chamber depth (ACD), anterior chamber volume (ACV), and angle parameters were analyzed before and after cataract surgery. RESULTS: IOP (p = 0.007), ACD (p < 0.001), ACV (p < 0.001), angle parameters (p = 0.001), and ITC index (p = 0.012) were improved after cataract surgery. ITC index decreased from 88.42 ± 23.59% to 48.91 ± 35.13% after cataract surgery (p = 0.012). There was no correlation between LV and ACD (p = 0.075), ACV (p = 0.864), angle parameter (p = 0.112-0.707), or ITC index (p = 0.288) before cataract surgery. The correlations between ITC index and IOP (p = 0.021), ACD (p = 0.002), ACV (p < 0.001), and angle parameter (p = 0.001-0.030) were statistically significant before surgery but not statistically significant (p = 0.223/0.206/0.761/ 0.096-0.819) after surgery. CONCLUSIONS: ITC index significantly improved after cataract surgery, but part of angle closure was not resolved in some cases of acute angle closure glaucoma.

Relationship between accommodation and lens vault following implantable contact lens surgery / 中华实验眼科杂志

Background Implantable contact lens (ICL) surgery is a primary intraocular refractive corrective surgery for high myopia.However,whether there will be enough distance between ICL and anterior face of lens to avoid the occurrence of anterior capsular cataract in non-accommodated and the largest physiological accommodated state after ICL implantation is worthy of investigation.Objective The purpose of this study was to investigate the alteration of lens vault after ICL implantation and explore the relationship between accommodation and change of lens vault.Methods A observational study was carried out.Sixty-six eyes of 33 patients with high myopia who received ICL implantation were enrolled in Affiliated First Hospital of Guiyang Medical College from May to November,2012.Best corrected visual acuity (BCVA),uncorrected visual acuity (UCVA),refractive diopter were regularly examined using synthetical optometry,and crystalline lens rise (CLR) and lens vault in non-accommodative or accommodative condition were observed by the anterior segment OCT (Visante OCT) and ultrasound biomicoscopy (UBM) before operation and 1 day,1 week,l month and 3 months after operation.Data were analyzed with SPSS version 16.0.Repeated measurement one-way analysis of variance was used to compare the differences of vision and refractive diopter among various time points.The relationship between accommodation and CLR was assessed using Pearson linear correlation.The alteration of CLR with accommodation change was analyzed by linear regression equation.Lens vault was measured and compared between non-accommodation and maximal physical accommodation status by paired t test.Results The postoperative UCVA was improved in comparison with preoperative BCVA,and the postoperative diopter was significantly lower than that of preoperation,with significant differences among various time points (F =16.904,P =0.000 ; F =1.498,P =0.000),and the diopter was stable after operation.A positive correlation was found between the alteration of CLR and accommodation under the physical accommodative stimulation in high myopic eyes (R2 =0.49,P =0.00).Under physiological accommodation,CLR elevated 20 μm for per 1.0 D accommodation.In addition,the difference of lens vault values within postoperative 3 months was statistically significant (F=16.025,P=0.000).The lens vault values lowed with the enlargement of accommodation in 48.5％ eyes,and the lens vault values increased with the enlargement of accommodation in 50.0％ eyes.However,1.5％ of the lens vault were in a stable state under the maximal physiological accommodated condition 3 months after operation.Lens vault were greater than zero in 97.0％ eyes (64/66),and only 3.0％ eyes (2/66) were zero under the maximalphysiological accommodated condition.Significant differences were seen in the lens vault between nonaccommodated and the maximal physiological accommodated state 1 day or 1 week after operation (t =4.755,P =0.000 ;t =3.327,P =0.001) ; but there was no statistical significance in 1 month or 3 months after operation (t =1.544,P=0.127,t=0.621,P=0.537).Conclusions During physiological accommodation,the alteration of CLR with accommodation in high myopic eyes.The location of ICL in the eyes is unstable within 3 months after operation.Majority of operative eyes remain enough vault in the maximal physiological accommodated state,but minority of operative eyes occur contact of ICL with the anterior surface of lens.Whether this contact causes anterior capsular cataract still needs to study.