PubMed Health⌕ Search

Biomedical subjects

Michael A Kapusta

Publications and source records attributed to Michael A Kapusta.

6 recordsLinked to original sources
PubMed2006

Macular hole: perceptual filling-in across central scotomas.

The present study examined perceptual distortions of a vertical line before and after macular hole (MH) surgery in 25 eyes of 24 patients. Participants' perceptual reports of distortions were classified as solid, bent right/left, thinned at the center, or broken. The majority of patients (72%) reported symmetrical distortions of the line pre-operatively. After surgery, participants with larger MHs were more likely to retain residual distortions. Of particular interest is the group reporting thinning of the line preoperatively, as the center should be perceptually missing. Examination of MH diameters in relation to the line perceptions indicated that the shape of the perceived line can be explained at the retinal level, while its continuity must be perceptually created at the cortical level.

Adult↗
PubMed2006

Differences between recognition and resolution acuity in patients undergoing macular hole surgery.

PURPOSE: The present investigation compared recognition acuities (ETDRS chart) with resolution acuities (Landolt-C chart) in a sample of patients with idiopathic macular holes (MH). Traditionally, visual acuity in a clinical setting is measured with a letter chart. Yet, the ability to recognize a letter differs from a resolution task, such as detecting the direction of a gap in a ring. It was hypothesized that resolution acuity would be more impaired than recognition acuity in patients with MH, because component cues in letter optotypes are not available in Landolt-Cs. METHOD: Visual acuities of 23 patients with MH (age range, 52-82) were tested, using standard ETDRS and Landolt-C charts. Optical coherence tomography was used to confirm the diagnosis of MH. RESULTS: Acuities correlated strongly, before and after surgery (r = 0.92 and r = 0.95, respectively). However, paired t-tests determined that resolution acuity was significantly more impaired at both time points than was recognition acuity (P < 0.001). Using Bland-Altman plots, the limits of agreement between the two acuity types indicated that resolution acuity differed from recognition acuity by up to five lines before surgery and up to 3 lines after surgery. CONCLUSIONS: ETDRS and Landolt-C acuities differ in a clinically significant way in patients before and after MH surgery. Measuring recognition acuity by reading letters may lead to an overestimate of visual ability at the retinal level in patients with MH by including compensatory top-down cognitive processes that are unavailable for resolution tasks.

Aged↗
PubMed2005

Visual function assessment and metamorphopsia after macular hole surgery.

The purpose of this study was to develop a new resolution acuity measure for patients after macular hole surgery. Fifty eyes of 44 patients who had undergone successful treatment were tested. Visual acuity was measured with the Snellen, Early Treatment of Diabetic Retinopathy Study and Landolt-C charts. A Line Resolution Test was performed as part of their follow-up exam where a vertical line was presented. Participants were categorized by their perception of the line as solid, bent or broken. The line could be distorted into a sine-wave pattern in order to determine the participants' detection threshold for the distortion. Chart acuities did not differ among the three groups, as categorized by their line perception. Only the distortion measure was sensitive enough to differentiate the solid- from the broken-line group. The distortion measure assesses resolution power of the macula in smaller increments than acuity charts. This hyperacuity approach is more appropriate in the assessment of functional outcome after microsurgery.

Aged↗
PubMed2004

Internal limiting membrane: ultrastructural relationships, with clinical implications for macular hole healing.

BACKGROUND: Recent data on macular hole formation have changed our understanding of the mechanisms involved. However, the mechanisms of macular hole closure, despite the introduction of internal limiting membrane (ILM) removal, are not fully understood. We reviewed the charts of patients who underwent surgery for macular hole with and without intentional removal of ILM and reviewed the basic science literature on the components and relationships of the ILM-glial cell interface to help interpret our surgical data. METHODS: We reviewed the records of 205 eyes with a clinical diagnosis of macular hole at a university centre in Montreal between 1998 and 2002. Of these, 117 eyes of 108 patients were included. Vitrectomy with intentional ILM removal was done under indocyanine green (ICG) staining. Macular hole stage and rates of hole closure, failure and reopening were recorded, comparing the eyes with intentional ILM peeling versus no ILM peeling. Anatomic success was defined as a flat/closed configuration. A basic science literature review was done through the PubMed search engine with the key words "internal limiting membrane," "internal limiting lamina," "macular hole," "retinal glial cells" and "retinal Müller cells." RESULTS: Eighty-four eyes had ICG-guided ILM removal (26 stage 2 macular holes, 45 stage 3 holes and 13 stage 4 holes), and 33 eyes had no ILM removal (10 stage 2 holes and 23 stage 3 holes). Of the 117 eyes 110 (94.0%) were successfully closed. Four (3.6%) of the closed holes reopened (none had ILM peeling), and 7 (6.0%) of the 117 eyes had primary failure. Ten of the 11 eyes that had primary failure or hole reopening were reoperated, and 8 were successfully closed after the second procedure. One patient refused reoperation. Including second procedures, the final anatomic closure rate was 97.4% (114/117). INTERPRETATION: Intentional ILM peeling is not mandatory for all macular holes to close but does play a role in preventing reopening. Removal of ILM increases the rate of flat/closed hole configuration on reoperation without the need for biologic adjuvants. Review of the basic science evidence helped clarify the possible role of ILM removal.

Coloring Agents↗