1. Iwona Helemejko, MD 1; D. Robert Iskander, PhD2
Relationship between lamina cribrosa displacement and structure-function parameters following glaucoma surgery
Patrycja Krzyżanowska-Berkowska, MD, PhD 1; Aleksandra Melińska, PhD 2;
Iwona Helemejko, MD 1; D. Robert Iskander, PhD2
1Wroclaw Medical University; 2Wroclaw University of Science and Technology
Purpose
Methods and Materials
To assess the displacement of lamina cribrosa (LC) and prelaminar tissue area (PTA) changes following trabeculectomy and non-penetrating deep sclerectomy (NPDS) using spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging (EDI) technology.
Sixteen patients underwent trabeculectomy and 13 patients undertook NPDS. The position of LC was estimated using OCT preoperatively, 1, 3, and 6 months and at follow-up postoperative visit (FUpv) (from 12 to 29 months postoperatively). Intraocular pressure (IOP), visual field parameters and OCT retinal nerve fiber layer (RNFL) parameters were measured before surgery, at 1, 3, 6pv and FUpv. A custom-written program was developed for the analysis of LC depth within the optic nerve head. Correlations between LC displacement and structure-function parameters were evaluated.
Results
IOP results are presented in Table 1. There was a significant decrease in the LC depth from a baseline glaucomatous LC displacement of ± µm to ± at 1 month, ± at 3 months, ± µm at 6pv and ± 90.3 at FUpv. The PTA differed between the procedures at baseline (P=0.002), but was not statistically significant postoperatively.
Statistically significant improvement of Mean RNFL parameter was found only at 1 month pv (p = 0.002), after 3 months we observed return to baseline values, and at 6 months and FU pv statistically significant thinning of Mean RNFL was found (p = 0.001; p = 0.031; p = 0.026, respectively). Results are presented in Figure 2.
Fig. 1. An example of infrared fundus photography and B-scan images obtained at baseline and methods for determination of LC and PTA.
Fig The time course of LC and mean RNFL parameters.
IOP (mmHg)
Before
6 pv
FU pv
TRAB
± 10.3
10.2 ± 4.0
12.7 ± 5.0
NDPS
19.9 ± 4.0
11.1 ± 3.6
12.8 ± 3.8
P-value
0.007
0.152
0.480
Conclusions
Statistically significant LC displacement has been associated with substantial IOP reduction. It could be speculated that the rapid change in the position of LC may be associated with further damage to the retinal nerve fibres. Further studies are needed to ascertain this speculation.
Table 1. Intraocular pressure parameters.
Contact
Patrycja Krzyżanowska- Berkowska MD, PhD
Wroclaw Medical University, Departament of Ophthalmology