Effect of Diode Laser Cyclophotocoagulation on the Anterior Segment: An Orbscan Study

An update on continuous-wave cyclophotocoagulation (CW-CPC) and micropulse transscleral laser treatment (MP-TLT) for adult and paediatric refractory glaucoma

PURPOSE

Continuous-wave cyclophotocoagulation (CW-CPC) is often preferred to medical and surgical treatments for managing refractory glaucoma. This review summarizes diode CW-CPC indications, history, histopathology, methods, efficacy and safety. It also provides an overview of the latest data available on micropulse transscleral laser treatment (MP-TLT) that uses repetitive micropulses of diode laser energy in an off-and-on cyclical fashion.

METHODS

A literature review was conducted on transscleral CW-CPC (CW-TSCPC), endoscopic CPC (ECP) and MP-TLT. Relevant series of adult and paediatric patients were included for assessing the procedures.

RESULTS

Regarding CW-TCPC, highly variable success rates are reported in the literature, depending on the definition of success, type of underlying glaucoma, energy settings, follow-up duration and retreatment rates. CW-CPC often needs to be repeated, especially in paediatric patients. CW-CPC exposes to risks of inflammation and chronic ocular hypotony or phthisis with irreversible visual loss. CW-TSCPC has mainly been used in very severe forms of glaucoma, in painful eyes with limited visual potential or after filtering surgery failure. Published data on ECP are more limited but overall good success rates have been reported. Through the direct visualization of the targeted ciliary body in anatomically abnormal eyes, ECP is the preferred surgical procedure in paediatric refractory glaucoma. Complication rates are relatively low after ECP; however, large studies with long-term follow-up are needed. ECP may be used in difficult, refractory cases, but it is often used earlier when combined with cataract surgery. Despite limited data on the exact mechanism of action of MP-TLT and a lack of standardization of laser settings, the first data from heterogeneous case series shows that it has a similar efficacy and a better safety profile compared to CW-TSCPC in the medium term.

CONCLUSION

Although they may lead to sight-threatening complications, both CW-TSCPC and ECP seem effective. ECP appears to be superior to CW-TSCPC in paediatric refractory glaucoma. Unlike ECP combined with cataract surgery, evidence supporting a wider use of CW-TSCPC and MP-TLT in earlier stages of neuropathy is lacking. While it now appears that the safety profile of MP-TLT is superior to that of CW-CPC, robust prospective comparative studies including homogeneous and well-defined cohorts of patients are still needed to confirm an at least comparable efficacy in the long term.

The Influence of Ultrasound Ciliary Plasty on Corneal Parameters

PRéCIS:: The ultrasound ciliary plasty (UCP) procedure affects corneal parameters, although the effect is transient. Ultrasound energy affects the sclera, leading to induced astigmatism. The area of energy application correlates with the astigmatism axis.

PURPOSE

To assess the postoperative corneal topography for 1 year after UCP.

MATERIALS AND METHODS

In total, 78 patients with primary and secondary refractory glaucoma were enrolled in the study. The primary outcome measures were the corneal parameters obtained with anterior segment swept-source optical coherence tomography. Intraocular pressure, number of antiglaucoma medications, and best-corrected logMAR visual acuities were analyzed as secondary outcome measures. Measurements were performed preoperatively and at 1 week, and 1, 3, 6, and 12 months postoperatively. A total of 39 patients (39 eyes) completed the follow-up period of 12 months.

RESULTS

There was a significant difference in the anterior/posterior steep/flat keratometry and anterior/posterior astigmatism values immediately after UCP. However, 3 months postoperatively these parameters returned to their initial values and there were no significant differences noted. The mean±SD values of anterior astigmatism preoperatively and at 1 week, and 1, 3, 6, and 12 months postoperatively were 1.12±0.66 D, 2.17±0.91 D (P<0.001), 2.05±0.93 D (P<0.001), 1.55±0.75 D (P=0.004), 1.31±0.70 D (P=0.024), and 1.20±0.73 D (P=0.406), respectively. The astigmatism axis tended to approach 90 degrees meridian with a significant difference 1 week postoperatively. Central and minimal corneal thickness remained unchanged, whereas the intraocular pressure and the number of antiglaucoma medications decreased significantly.

CONCLUSIONS

UCP influenced the corneal topography parameters in the immediate postoperative period; however, with time, all parameters returned to their initial values.

Comparing the efficacy of trabeculectomy and diode laser cyclophotocoagulation in primary open-angle glaucoma

PURPOSE

The aim was to compare the postsurgical outcomes of trabeculectomy (TET) and transscleral cyclophotocoagulation (CPC) in a similar cohort of eyes diagnosed with primary open-angle glaucoma (POAG).

MATERIALS AND METHODS

For this monocentric non-randomized retrospective comparative trial, the records of eyes which underwent TET or CPC between 2013 and 2016 at our institution for the treatment of POAG were reviewed. Parameters analyzed before surgery as well as 1 and 2-3 years afterwards were visual acuity (VA), intraocular pressure (IOP), mean defect (MD) of the visual field, number of glaucoma medications and the objective refraction using which the surgically induced astigmatism (SIA) was calculated.

RESULTS

In total, 51 eyes of 51 patients underwent TET and 45 eyes of 45 patients underwent CPC. Mean VA dropped in both groups on the last follow-up after surgery (TET-group: 0.17 ± 0.17 to 0.23 ± 0.28 logMAR, p = 0.01/CPC-group: 0.22 ± 0.22 to 0.26 ± 0.27 logMAR, p = 0.01). In the TET- and CPC-groups IOP decreased significantly (TET: 24.9 ± 6.4 to 14.9 ± 3.1 mmHg, p = 0.001/CPC: 23.0 ± 6.5 to 16.0 ± 4.1 mmHg, p = 0.001) although more pronounced and less depending on IOP-lowering medication in eyes after TET. MD remained stable after TET (7.4 ± 4.8 and 8.1 ± 4.9 dB, p = 0.1) but further deteriorated in eyes after CPC (9.0 ± 4.9 and 10.7 ± 4.6 dB, p < 0.001). SIA was comparable in both groups on the last follow-up (TET: 0.83 ± 0.69 D; CPC: 0.91 ± 0.65 D, p = 0.6).

CONCLUSION

The IOP reduction achieved without medication was more pronounced in the TET-group compared with the CPC-group. Visual field remained stable in the TET-group, while further deteriorating in the CPC-group during follow-up. Eyes undergoing CPC had a higher demand for additional medication to reach comparable success rates as TET. Due to this performing TET is favorable over CPC in POAG eyes.

Corneal curvature and thickness development in premature infants

PURPOSE

Analysis of postnatal changes in central corneal thickness (CCT) and corneal curvature (CC) in premature infants, their relation, and their possible influence on eye growth and intraocular pressure (IOP) evaluation.

METHODS

CCT and CC were assessed in both eyes of 56 premature infants, born at 24 to 32 weeks of gestational age (GA), and then two or three times at post-conceptional ages (PCAs) of 28 to 42 weeks.

RESULTS

CC changed from 65.83 diopters at 28 weeks of PCA to 49.38 diopters at 42 weeks of PCA. CCT decreased from 794 to 559 μm at the same ages. The reductions of these two corneal parameters seem to be related to each other and begin immediately after birth.

CONCLUSION

In light of the few data available in the literature, these data provide more certainty about the CCT values of premature infants. The importance of CCT and CC fast variations after premature birth concerns both the knowledge of anterior segment development and the correct evaluation of IOP in immature eyes; the influence of these two parameters on the methods of IOP evaluation could be more remarkable at the lowest PCAs.