Kristian Krøyer

Value of internal limiting membrane peeling in surgery for idiopathic macular hole stage 2 and 3: a randomised clinical trial.

Aim: To determine the effect of internal limiting membrane (ILM) peeling on anatomical and functional success rates in stage 2 and 3 idiopathic macular hole surgery (MHS). Methods: Randomised clinical trial of stage 2 and 3 idiopathic macular hole without visible epiretinal fibrosis and with less than 1 year’s duration of symptoms. Eyes were randomised to (1) vitrectomy alone without retinal surface manipulation, (2) vitrectomy plus 0.05% isotonic Indocyanine Green (ICG)-assisted ILM peeling or (3) vitrectomy plus 0.15% Trypan Blue (TB)-assisted ILM peeling. Main outcomes were hole closure after 3 and 12 months and best-corrected visual acuity after 12 months. Results: 78 eyes were enrolled. Primary closure rates were significantly higher with ILM peeling than without peeling for both stage 2 holes (ICG peeling 100%, non-peeling 55%, p = 0.014) and for stage 3 holes (ICG peeling 91%, TB peeling 89%, non-peeling 36%, p<0.001). Visual outcomes in eyes with primary hole closure were not significantly different between the groups. Conclusions: Dye-assisted ILM peeling was associated with significantly higher closure rates than non-peeling in both stage 2 and 3 MHS. Intraoperative ILM staining with 0.05% isotonic ICG was not associated with a significantly different visual outcome than non-peeling or TB peeling in eyes with primary hole closure. Trial registration number: NCT00302328.

Prognostic Significance of Delayed Structural Recovery after Macular Hole Surgery

PURPOSE To assess the prognostic significance for visual function of persistent subfoveal fluid and persistent photoreceptor layer discontinuity in eyes in which hole closure had been obtained 3 months after macular hole surgery. DESIGN Ancillary study of subjects enrolled in a randomized clinical trial. PARTICIPANTS Participants were recruited from a randomized clinical trial evaluating internal limiting membrane (ILM) peeling in macular hole surgery. The study included 74 eyes in which a contiguous retinal surface or a full attachment with a flat neuroretinal rim had been reestablished after macular hole surgery. METHODS Contrast-enhanced optical coherence tomography was used to detect closure defects involving substrata of the retina with particular emphasis on the photoreceptor layer. Outcomes were compared with best-corrected visual acuity (BCVA) 12 months after surgery. MAIN OUTCOME MEASURES Postoperative foveal configuration and foveal photoreceptor layer discontinuity diameter 3 months after macular hole surgery. RESULTS Persistent subfoveal fluid 3 months after macular hole surgery, which was found in 36.5% of eyes, was not associated with a significantly different BCVA after 12 months compared with eyes with a fully attached fovea at 3 months (70.9 letters vs. 72.0 letters; P = 0.59). Receiver operating characteristics curve analysis identified persistent photoreceptor layer discontinuity of a diameter of more than 1477 microm after 3 months to be associated with poorer BCVA after 12 months (P<0.001), yet an overall reduction in discontinuity diameter from 3 to 12 months (P<0.001) was not correlated with a concurrent improvement in BCVA (r = -0.040; P = 0.81). Persistence of fluid and diameter of discontinuity at 3 months were not related to whether ILM peeling was used; however, secondary macular hole surgery had a significant influence on diameter of photoreceptor layer discontinuity at 3 months. CONCLUSIONS Structural recovery in the form of photoreceptor layer discontinuity with a diameter of more than approximately 1500 microm 3 months after macular hole surgery was associated with poorer visual acuity after 12 months than less extensive discontinuity. Subfoveal fluid persisting after 3 months had disappeared after 12 months in all but 5 of 74 eyes and had no effect on final visual outcome.

Macular morphology and visual acuity after macular hole surgery with or without internal limiting membrane peeling

Aim: To examine postoperative macular morphology and visual outcome after 12 months in relation to internal limiting membrane (ILM) peeling versus no peeling, indocyanine green (ICG) staining and re-operation in eyes that achieved macular hole closure after surgery. Methods: Seventy-four eyes with closed stage 2 or 3 macular holes were recruited from a randomised clinical trial comparing: (1) vitrectomy without ILM peeling; (2) vitrectomy with 0.05% isotonic ICG-assisted ILM peeling; and (3) vitrectomy with 0.15% trypan blue-assisted ILM peeling. Contrast-enhanced Stratus optical coherence tomography was used to assess central foveal thickness, central photoreceptor layer thickness (CPRT), central photoreceptor layer discontinuity (PRD) and relative reflectivity of the outer nuclear layer. Outcomes were correlated with best corrected visual acuity (BCVA) 12 months after surgery. Results: BCVA was correlated with CPRT and PRD. Regression analysis and receiver operating characteristics curve analysis showed that CPRT >33 μm (OR 12.5) and PRD <177 μm (OR 9.86) were highly predictive for regaining reading vision (⩾69 Early Treatment of Diabetic Retinopathy Study letters) 12 months after surgery. No significant difference was found in postoperative macular morphology between subgroups. Conclusions: Poor vision after 12 months despite macular hole closure was associated with attenuation and disruption of the foveolar photoreceptor matrix. The extent of attenuation and disruption was independent of peeling and staining. Trial registration number: NCT00302328

Normative data of outer photoreceptor layer thickness obtained by software image enhancing based on Stratus optical coherence tomography images

Aim: To present normative data of outer photoreceptor layer thickness obtained by a new semiautomatic image analysis algorithm operating on contrast-enhanced optical coherence tomography (OCT) images. Methods: Eight Stratus OCT3 scans from identical retinal locations from 25 normal eyes were registered and combined to form a contrast-enhanced average image. Utilising the vertical intensity gradients of the enhanced OCT images to demarcate retinal layers, thickness measurements of the outer photoreceptor- and retinal pigment epithelium layer (RPE-OScomplex) were obtained. Additionally backscattered light within the outer nuclear layer (ONL) in the fovea was registered and compared with backscattered light within the ONL in the peripheral part of the macula (Iratio-ONL). Results: The mean RPE-OScomplex thickness in the foveal centre was 77.2 μm (SD = 3.95). The RPE-OScomplex thickness in the superior macula 0.5–3 mm of the centre was significantly increased as compared with the corresponding inferior retina. In healthy subjects, the Iratio-ONL was 1.06. Conclusions: Contrast-enhanced OCT images enable quantification of outer photoreceptor layer thickness, and normative values may help understanding better the relationship between functional outcome and photoreceptor morphology in retinal diseases.

Quantification of Metamorphopsia in Patients with Macular Hole

PURPOSE To describe a novel method for the evaluation of metamorphopsia within the central 10 degrees of the visual field in 55 patients with idiopathic macular hole. The test evaluates the interocular disparity between the two eyes in metamorphopsia. METHODS Semicircular test and reference stimuli of variable diameters were used in a binocular test that measured interocular size disparity between perceptually iseikonic stimuli in subjects with a unilateral macular hole. A group of 11 healthy subjects was used as the reference. RESULTS In 55 patients with a macular hole, interocular disparity demonstrated a mean value of 0.71 degrees with stimuli in the range 1.0 degrees to 2.5 degrees in diameter. This number declined to 0.41 degrees with stimuli in the range of 9.0 degrees to 10.0 degrees in diameter. Both hole diameter and eccentricity had a significant effect on mean disparity (P < 0.001). CONCLUSIONS The level of metamorphopsia declined as a function of eccentricity and affected the central 10 degrees of visual field. Macular hole size had an independent effect on interocular disparity. These results confirm reports that visuospatial distortion in the presence of macular hole is primarily the result of radial displacement of photoreceptors. (ClinicalTrials.gov number, NCT00302328.).

Metamorphopsia Assessment before and after Vitrectomy for Macular Hole

PURPOSE To evaluate the degree of metamorphopsia in 42 patients before and 6 months after vitrectomy for idiopathic unilateral macular hole. METHODS Semicircular test and reference stimuli of variable diameters were applied in a binocular test that measured interocular size disparity in patients with unilateral macular hole. The test was applied 1 day before surgery and repeated after 6 months. RESULTS Before surgery, mean disparity was 0.34 degrees at 1 degrees visual field eccentricity declining to a plateau value of approximately 0.2 degrees between 3 degrees and 5 degrees of eccentricity. Six months after successful hole closure, interocular disparity was practically constant, with a median disparity below 0.1 and no significant effect of eccentricity. Baseline interocular disparities lower than 0.35 degrees at 1 degrees eccentricity were associated with nine EDTRS letters of better visual outcome compared with higher disparities (P < 0.001). CONCLUSIONS Metamorphopsia was consistently reduced after macular hole surgery, supporting that the intervention was successful in repositioning displaced photoreceptors toward their original location. Final best corrected visual acuity was related to the degree of preoperative disparity in spatial projection between receptive units with a shared perceptual projection in visual space in the two eyes. (ClinicalTrials.gov number, NCT00302328.).

Dissociation of rod and cone sensitivity by acute localized retinal pigment epithelium loss

Purpose:  To assess the impact of acute retinal pigment epithelium (RPE) loss on photopic and scotopic sensitivity.