Abstract
Purpose: :
To evaluate the morphological abnormalities preceding the development of a lamellar hole using optical coherence tomography (OCT) scans in eyes with macular edema.
Methods: :
Time domain OCT scans (Stratus) evaluated in multiple clinical trials (macular edema due to diabetes or retinal vein occlusion) that developed lamellar holes during the course of the trial were identified. The criteria for identifying lamellar holes includes abnormal foveal contour with steep sides or anvil shape, with a deficiency of inner retinal layers. OCT scans for the visit preceding the development of the lamellar hole (pre-hole visit) and the hole visit were evaluated longitudinally by trained ocular disease evaluators for center point thickness, central subfield thickness, epiretinal membrane (ERM), posterior vitreous detachment (PVD), cysts and subretinal fluid (SRF).
Results: :
Lamellar hole was identified in 81 of 8,999 eyes evaluated in multiple clinical trials. The mean duration between the pre-hole and hole visit was 3.7 ± 9.3 months. The mean center point thickness decreased from pre-hole to hole visit (526 ± 1036µm and 95 ± 350µm, respectively). The average central subfield thickness was 420 ± 370µm in the pre-hole visit, but was found to be unreliable in 80 out of 81 cases in the hole visit due to erroneous boundary lines. ERM in the central subfield was identified in 48 (59%) eyes at the pre-hole visit and 57 (70%) eyes at the hole visit. Tractional PVD was present in 6 (7%) at the pre-hole visit and 2 (2%) at the hole visit. In the pre-hole visit, cysts were present in the central subfield in 79 (98%) eyes; 42 small, 21 medium and 16 large. The distance between the ILM and the top of the central cyst was < 1mm in 42 (53%) eyes. At the hole visit, 61 (75%) had cysts; 50 small, 11 medium and none large. SRF was seen in 9 eyes at the pre-hole visit and 5 eyes at the hole visit. The mean hole diameter (opening) was 351 ± 444µm and the hole shape was predominantly anvil shaped. The lamellar hole persisted until the end of the study in 64 eyes (mean duration 16.4 ± 33 months).
Conclusions: :
Lamellar macular holes are infrequent complications of macular edema due to diabetes and retinal vein occlusion. Antecedent lesions included retinal cysts nearly always and ERM was frequent. Development of a lamellar hole results in an abrupt decrease in the retinal thickness measurement which may be mistaken for a positive treatment effect if the underlying scans are not assessed.
Keywords: macular holes • imaging/image analysis: clinical • retina