Corneal Configurations and High-order Aberrations in Primary Congenital Glaucoma:

Pediatric Glaucoma-From Screening, Early Detection to Management

Pediatric glaucoma (PG) covers a rare and heterogeneous group of diseases with variable causes and presentations. Delayed diagnosis of PG could lead to blindness, bringing emotional and psychological burdens to patients' caregivers. Recent genetic studies identified novel causative genes, which may provide new insight into the etiology of PG. More effective screening strategies could be beneficial for timely diagnosis and treatment. New findings on clinical characteristics and the latest examination instruments have provided additional evidence for diagnosing PG. In addition to IOP-lowering therapy, managing concomitant amblyopia and other associated ocular pathologies is essential to achieve a better visual outcome. Surgical treatment is usually required although medication is often used before surgery. These include angle surgeries, filtering surgeries, minimally invasive glaucoma surgeries, cyclophotocoagulation, and deep sclerectomy. Several advanced surgical therapies have been developed to increase success rates and decrease postoperative complications. Here, we review the classification and diagnosis, etiology, screening, clinical characteristics, examinations, and management of PG.

Ocular aberrations in eyes with Primary Congenital Glaucoma

PURPOSE

To highlight the magnitude of ocular higher order aberrations (HOA) and lower order aberrations (LOA), including component contributions from corneal and internal planes in Primary Congenital Glaucoma (PCG) patients.

METHODS

Consecutive treated PCG patients co-operative for ocular examination and aberrometry, were enrolled over two years for this cross-sectional, comparative, single centre, unmasked study. Best corrected visual acuity, refraction, IOP, wavefront aberrometry and topography (iTrace) were performed and results were compared with unaffected fellow eyes of unilateral glaucoma patients as well as age and sex matched controls with no ocular anomalies other than treatable refractive error.

RESULTS

Both eyes of 32 consecutive PCG patients (17 unilateral, 15 bilateral) and 39 controls were enrolled. The median LogMAR corrected distance visual acuity of PCG eyes was 0.68 (IQR: 0.2 - 1.8). Total ocular (Root mean square (RMS) 1.7µm vs 0.3µm, p = 0.014), corneal (RMS 1.1µm vs 0.3µm, p = 0.004) and internal (RMS 1.1µm vs 0.2µm, p = 0.013) aberrations, as well as HOAs and LOAs at each plane were significantly higher in PCG eyes than in controls. Component HOAs from corneal and internal planes were positively correlated with each other (p < 0.001; rs: 0.7). Total aberrations were greater in the affected eyes of PCG compared to the rest. The predominant subtype of HOAs in PCG were coma and trefoil. PCG with corneal opacity/Haab's striae had significantly higher astigmatism than the affected eyes with clear corneae at corneal plane (p = 0.02). The aberrations were not statistically associated with the corneal diameter or refractive error in PCG eyes.

CONCLUSIONS

Significantly greater aberrations (Total, HOAs and LOAs, at corneal as well as internal plane) were seen among eyes affected with PCG. Though the exact impact of these aberrations on the final visual outcome is difficult to determine, these could play a pertinent role in compromising visual function, thus impacting the management of visual rehabilitation in these patients.

Scheimpflug Imaging in Operated Primary Congenital Glaucoma

PURPOSE

To report the corneal tomographic characteristics of eyes that had surgery for controlled primary congenital glaucoma (PCG) and to compare it with an age-matched group of normal children.

METHODS

The study was conducted on 44 (24 right) eyes of 27 children (18 boys) who had surgery for PCG and 60 (31 right) eyes of 32 age-matched control children (9 boys). Children with PCG had a thorough ophthalmic examination and the demographic and medical and surgical history was retrieved from the patients' clinical chart records. After clinical examination, the study participants underwent Scheimpflug imaging using the Pentacam (Oculus Optikgeräte GmbH).

RESULTS

Both study and control children were approximately 9 years of age at the time of the study (P = .39). The eyes with PCG had a spherical equivalent mean ± standard deviation of -4.70 ± 3.50 diopters (D). Eyes with PCG demonstrated a cylinder of -2.80 ± 2.10 D, flatter corneas than control eyes (P = .0002 and .0012 for flat and steep keratometry, respectively), and statistically significantly higher astigmatism (P = .011) and thinner corneas, both at pupil center (P < .001) and thinnest location (P < .001). There was a statistically significant negative correlation between the postoperative axial length (at the time of the scan) and each of the Scheimpflug parameters flat keratometry (P = .002), steep keratometry (P = .003), pachymetry at pupil center (P = .01), and pachymetry at thinnest location (P = .009).

CONCLUSIONS

The eyes of patients with PCG have thinner, flatter, and more astigmatic corneas than the eyes of age-matched control children. [J Pediatr Ophthalmol Strabismus. 2021;58(4):218-223.].

Long-term structural and functional outcomes of primary congenital glaucoma

PURPOSE

To investigate the clinical characteristics and long-term outcomes of primary congenital glaucoma (PCG) patients.

METHODS

In this retrospective, longitudinal, cohort study, PCG patients with reliable visual field (VF) tests and optical coherence tomography (OCT) were included. Disease progression was detected using guided progression analysis with OCT and the change analysis of mean deviation (MD) slope with VF tests. Factors associated with the disease progression and visual prognosis were analyzed.

RESULTS

Twenty-nine eyes from 11 bilateral and 7 unilateral PCG patients were enrolled. LogMAR visual acuity declined (0.15 vs. 0.40, P < 0.001). The change rate of the average retinal nerve fiber layer thickness was - 0.83 ± 1.45 µm/year, and 28% of eyes showed glaucoma progression on OCT. The median of the MD slope was 0.16 (- 1.19 to 1.07) dB/year, and 14% of eyes showed glaucoma progression on the VF test. Higher average intraocular pressure (IOP) (P = 0.046) and IOP fluctuation (P = 0.031) predicted disease progression. None of the fellow eyes of unilateral PCG patients developed glaucoma during the follow-up. At last, 59% of eyes had visual acuity > 20/70, and 31% had MD >  - 6 dB. Patients with worse baseline visual acuity (P = 0.027), worse baseline MD (P < 0.001), and smaller neuroretinal rim area (P < 0.001) showed worse final MD values.

CONCLUSIONS

Aggressive IOP control is necessary to prevent structural and functional decline in PCG patients. Their fellow eyes are not at risk of glaucoma. Baseline neuroretinal rim area can predict the functional outcome.

Pentacam corneal densitometry-guided treatment of adenoviral corneal subepithelial infiltrates: a comparative study between transepithelial phototherapeutic keratectomy and topical tacrolimus

PURPOSE

To compare the changes in the measurement of corneal densitometry and total corneal higher-order aberrations (HOAs) between topical tacrolimus and transepithelial phototherapeutic keratectomy (Te-PTK) in the treatment of adenoviral corneal subepithelial infiltrates (SEIs).

SUBJECT AND METHODS

This is an interventional prospective randomized study, including 63 eyes of 35 patients with symptomatic adenoviral corneal SEIs for at least 6 months. All patients underwent previous topical steroid therapy associated with unsatisfactory response and/or complications. Patients were assigned into three groups: (1) Te-PTK group: Te-PTK with MMC 0.02% was performed by a Technolas; Teneo excimer laser; (2) tacrolimus group: tacrolimus 0.03% ointment was applied once daily for 2-6 months; the endpoint of treatment was based on the improvement in the corneal densitometry, BCVA, and OSDI; and (3) control group: no intervention was done. BCVA, corneal densitometry, and total corneal higher-order aberrations (HOAs) evaluation using Pentacam HR were done at the baseline, 1 week, and then 1, 3, 6, and 12 months of the study.

RESULTS

The study population was similar between all groups. The mean follow-up was 12.75 ± 0.9 months. Bilateral corneal SEI was recorded at 80%. At 12-month follow-ups, the mean BCVA improved in both the Te-PTK and tacrolimus groups without significant changes in the control group. The mean corneal densitometry of the anterior, central, and total cornea decreased significantly in the Te-PTK and tacrolimus groups. HO-RMS and total RMS decreased significantly in the Te-PTK and tacrolimus groups. BCVA, corneal densitometry (anterior, central, and total cornea), and corneal aberrations (total coma, total trefoil, HO-RMS, and total RMS) values were significantly better for the Te-PTK and tacrolimus groups than the control group. There were no statistically significant differences between Te-PTK and tacrolimus groups in terms of BCVA, corneal densitometry, corneal HOA, and the persistence of corneal SEIs. The persistence of corneal SEIs was significantly lower in Te-PTK and tacrolimus groups than the control group.

CONCLUSION

Te-PTK and topical tacrolimus are effective methods for the treatment of adenoviral corneal SEIs improving visual acuity, corneal densitometry, and corneal HOA. The densitometry program of the Pentacam may give an objective guide for the treatment of adenoviral corneal SEIs.

TRIAL REGISTRATION

ClinicalTrials.gov ID is NCT04267991.