To study whether the accommodation response to Badal optometer is equivalent to the response for real space targets.
Accommodative responses were measured for 28 young eyes with the WAM-5500 autorefractometer in eight configurations for 0.17 D, 2.0 D and 5.0 D accommodation stimuli. Parameters that might contribute to differences in response were systematically isolated: stimulation method (real space vs Badal targets), field of view, instrument's cover proximity, the looming effect, and the peripheral interposition of objects in depth.
Mean accommodative response differences between a natural view configuration and a configuration with a Badal Optometer were 0.50 ± 0.43 D and 0.58 ± 0.53 D for 2.0 D and 5.0 D stimulation, respectively (p < 0.001), with accommodation lags for the latter condition. Of the isolated parameters that might contribute to these differences, varying the interposition of objects in depth affected accommodation response more markedly.
It is likely that Badal optometers affect accommodation through a combination of some or all of the studied parameters. We conclude that accommodation response to closed-view Badal optometers is not equivalent to real space target response.
PurposeTo establish the sequence of tomographic changes in the tissue recovery process after pterygium excision and to propose healing indicators.; MethodsOptical coherence tomography (OCT) images were taken at 1week, 1, 3 and 6months after lesion excision in 73 eyes of 73 patients (33 male, 40 female; mean age 50, S.D. 5.0, range 40-70years) with primary nasal pterygium. Biomicroscopy was performed at each visit and at 12months, to diagnose clinical healing or lesion recurrence. The presence of well demarcated corneal epithelium, conjunctival epithelium, limbal demarcation area, and graft thickening were analysed. Comparisons between tomographic data of both clinical situations were made at each time point using contingency tables.; ResultsEleven eyes displayed lesion recurrence (R group) and 62 eyes showed no recurrence (NR group). Normal anatomical structures, corneal and conjunctival epithelium and limbal demarcation area, were identified by OCT images in a higher percentage of NR cases over time, compared to the R group where most of the cases presented without these markers of tissue recovery. In contrast, the variable graft thickening, which analysed a pathological event, revealed similar results in both groups (p>0.05; Fisher's exact statistic), with a clear decrease of cases which showed graft thickening over time. Differences between groups started at 1month, when no eye had yet presented clinical recurrence, with greater identification of corneal epithelium in the NR group (p=0.04; Fisher's exact statistic). At 3months, corneal and conjunctival epithelium identification tended to be more frequent in the NR than in the R group (in both cases, p=0.0001; Fisher's exact statistic). Finally, at 6months these different patterns consolidated, with a significantly higher number of limbal demarcation areas being identified in the NR group (p=0.001; Fisher's exact statistic). In fact, this landmark of a normally structured limbus was never found in the R group.; ConclusionsThe sequence of tissue restoration, according to OCT images, seems to start in the cornea and end in the limbal area, similar to the process of pterygium injury in reverse. Although the visualisation of corneal epithelium could be an early indicator of successful surgery, identification of the limbal demarcation area, as a normal limbal pattern in OCT images, seems to be a better positive predictive value in diagnosing healing.