Evaluation of corneal biomechanical properties using an ocular response analyser to examine aphakic and pseudophakic patients after congenital cataract surgery

Corneal characteristics and OCT-angiography findings in pediatric glaucoma and glaucoma suspects

PURPOSE

To analyze corneal biomechanics, specular microscopy, and optical coherence tomography-angiography findings in children with glaucoma.

METHODS

Pediatric patients (<18 years of age) with glaucoma (n = 38), increased cup:disk ratio and normal intraocular pressure (IOP) glaucoma suspects (n = 36), and controls (n = 67) were prospectively enrolled. Patients underwent testing with Ocular Response Analyzer, CellChek Specular Microscope, and Heidelberg OCT-A.

RESULTS

Average age of participants was 12.4 ± 3.5 years, with no difference between groups (P = 0.71). Glaucoma patients had undergone more intraocular surgeries (P < 0.0001) and showed worse logMAR visual acuity (P < 0.0001) than suspects or controls. Central corneal thickness (CCT) was greater in glaucoma patients (642.8 ± 85.9 μm [P < 0.0001]) and suspects (588 ± 43.7 μm [P = 0.003]) compared with controls (561 ± 39.9 μm). Corneal hysteresis (CH) was decreased in eyes with glaucoma (10.4 ± 3.0) compared with controls (11.7 ± 1.5 [P = 0.006]), but not suspects (11.3 ± 2.0 [P = 0.1]). Glaucoma patients had lower endothelial cell density (2028.4 ± 862.7 [P < 0.0001]) and greater average cell area (547.2 ± 332.4 [P < 0.0005]) compared with suspects (2919.3 ± 319.1, 347.5 ± 46.2) and controls (2913.7 ± 399.2, 350.8 ± 57.7), but there was no difference in polymegathism (P = 0.12) or pleomorphism (P = 0.85). No differences in vessel density or vessel skeletal density in the retinal vascular complex (P = 0.3077, P = 0.6471) or choroidal vascular complex (P = 0.3816, P = 0.7306) were detected.

CONCLUSIONS

Children with glaucoma showed thicker corneas with lower endothelial cell density and greater cell area, but no difference in retinal/choroidal vascular densities compared with suspects and controls.

Preoperative Characteristics of Ocular Biometry in Children with Unilateral Congenital Cataracts

The ocular biometry characteristics are clinically significant for children with unilateral congenital cataracts, but there is a lack of data analysis concerning the preoperative measurements. The axial length (AL), mean keratometry (Km), corneal astigmatism (CA), and the anterior chamber depth (ACD) from both eyes before cataract surgery were obtained from 205 patients (410 eyes, 3-15 years of age) with unilateral congenital cataracts. In the congenital cataract eyes, shorter AL (22.44 ± 1.52 mm vs. 22.57 ± 1.04 mm, p = 0.036) and higher CA (- 1.89 ± 0.91 D vs. - 1.24 ± 0.67 D, p < 0.001) were found, and no significant difference was found in the Km and the ACD measurements compared to the contralateral normal eyes. Females had shorter AL and shallower ACD compared to males. However, the Km and CA in the females were significantly larger than that in males. Shorter AL, larger Km, higher CA, and shallower ACD were also found in females who had a binocular axial difference (the value obtained by subtraction of the contralateral normal eye from the congenital cataract eye) that less than zero. The preoperative ocular biometry of shorter AL, larger Km, higher CA, and shallower ACD should be considered in females with unilateral congenital cataracts. The age and the binocular axial differences had a statistically significant correlation (r = -0.192, p = 0.006). Therefore, changes in the binocular axial differences associated with aging may enhance the guidelines for intraocular lens selection and the management of congenital cataracts.

Incidence of and Risk Factors for Suspected Glaucoma and Glaucoma After Congenital and Infantile Cataract Surgery: A Longitudinal Study in China

PRéCIS:: The overall incidence of postoperative suspected glaucoma and glaucoma after congenital cataract surgery is low; however, the identification of the associated risk factors helps to monitor susceptible individuals and to provide real-time surveillance and timely intervention.

PURPOSE

Pediatric patients who have undergone surgery for congenital or infantile cataracts have a risk of developing suspected glaucoma and glaucoma, but the current evidence does not address our understanding of the incidence and associated risk factors of suspected glaucoma/glaucoma for application in clinical standard care. Therefore, this study investigated the incidence of and risk factors for suspected glaucoma/glaucoma in patients who have undergone surgery for congenital/infantile cataracts.

METHODS

This study used a prospective cohort of 241 eyes from 241 patients who were 10 years of age or younger and who had undergone congenital/infantile cataract surgeries and were recruited from January 2011 to December 2016 at the Zhongshan Ophthalmic Center. Pediatric patients who underwent cataract surgery were classified into 2 groups according to intraocular lens (IOL) implantation. The patients' baseline characteristics and the incidence and risk factors for suspected glaucoma/glaucoma were assessed.

RESULTS

The incidence of suspected glaucoma after cataract surgery was 10.70% [26 of 241 eyes; 95% confidence interval (CI), 6.88%-14.70%]. The rate of suspected glaucoma developing into glaucoma was 26.92% (7 of 26 eyes; 95% CI, 9.87%-43.97%), and the incidence of glaucoma was 2.90% (7 of 241 eyes; 95% CI, 0.79%-5.03%). Our study revealed that the incidence of suspected glaucoma/glaucoma in patients who did not receive IOL implantation was 13.91% (21 of 151 eyes; 95% CI, 8.39%-19.42%), and the incidence in patients who received IOL implantation was 5.56% (5 of 90 eyes; 95% CI, 8.23%-10.28%). The preoperative central corneal thickness (hazard ratio, 1.003; 95% CI, 1.001 to 1.004; P=0.004) and a family history of congenital cataracts (hazard ratio, 2.314; 95% CI, 1.004-5.331; P=0.049) were significant risk factors in patients without IOL implantation. Patient age at the time of cataract surgery was not a statistically significant risk factor for the development of suspected glaucoma/glaucoma in patients without IOL implantation.

CONCLUSIONS

Identification of the incidence of and risk factors for suspected glaucoma/glaucoma may help clinicians monitor susceptible individuals and provide timely surveillance and interventions in a clinical setting. Age at the time of cataract surgery was not a risk factor for suspected glaucoma/glaucoma in patients without IOL implantation, and this may allow the timing window for pediatric cataract surgery to be expanded and support new insights into the optimal timing of surgery for standard care.

Goldmann applanation tonometer versus ocular response analyzer for measuring intraocular pressure after congenital cataract surgery

PURPOSE

To compare intraocular pressure measured using the Goldmann applanation tonometer with that measured using the ocular response analyzer after congenital cataract surgery.

METHODS

This study included 113 eyes of 64 patients who underwent lensectomy and vitrectomy. In all, 36 eyes remained aphakic after surgery. Intraocular lens implantation was performed at the time of surgery in 47 eyes and secondarily in 30 eyes. Corneal hysteresis, corneal resistance factor, and cornea-compensated intraocular pressure were measured. The influences of independent factors on the difference between the cornea-compensated intraocular pressure and intraocular pressure measured with Goldmann applanation tonometer were investigated using linear regression analyses. Agreement between the two tonometers was investigated using the Bland and Altman and 95% limits of agreement analysis.

RESULTS

Central corneal thickness, corneal hysteresis, and corneal resistance factor were 591.2 ± 53.3 µm, 10.83 ± 2.27 mmHg, and 11.36 ± 2.14 mmHg, respectively. Cornea-compensated intraocular pressure (16.75 ± 4.82 mmHg) was significantly higher than intraocular pressure measured with Goldmann applanation tonometer (14.41 ± 2.27 mmHg, p < 0.001). Central corneal thickness (p = 0.02) and corneal hysteresis (p < 0.001) were identified as the main predictors of difference between cornea-compensated intraocular pressure and intraocular pressure measured with Goldmann applanation tonometer readings. A 95% limits of agreement for cornea-compensated intraocular pressure and intraocular pressure measured with Goldmann applanation tonometer was between -4.86 and 9.53 mmHg in the entire group. Cornea-compensated intraocular pressure showed the best agreement with intraocular pressure measured with Goldmann applanation tonometer in the primary pseudophakic subgroup as compared to the other subgroups.

CONCLUSION

The Goldmann applanation tonometer and ocular response analyzer cannot be used interchangeably for measuring intraocular pressure after congenital cataract surgery. The difference between the cornea-compensated intraocular pressure and intraocular pressure measured with Goldmann applanation tonometer was primarily affected by central corneal thickness and corneal hysteresis. Among the subgroups, the primary pseudophakic subgroup had the thinnest cornea and the highest corneal hysteresis values and demonstrated the best agreement between the two tonometers.