Fixation Stability Deficits in Anisometropic Amblyopia

Abstract

Purpose The purpose of this study was to investigate the relationship between fixation stability deficits in anisometropic amblyopia and various visual functions, as well as the underlying retinal structure. Methods All 164 patients with anisometropic amblyopia were recruited in this cross-sectional study. The contrast sensitivity function (CSF) was measured using the qCSF method, whereas the MP-3 microperimeter was used to assess fixation stability and locate the preferred retinal locus. Bivariate contour ellipse area (BCEA) of both the amblyopic and the fellow eyes was used as the dependent variable. Based on previous research and clinical practice, the following variables were selected as independent variables for regression modeling to explore potential influencing factors: gender, age, area under the log CSF (AULCSF), absolute interocular difference (IOD) in spherical equivalent refraction (SER), AULCSF-IOD, the eccentricity of the preferred retinal locus, patching history, and the log BCEA of the contralateral eye. Results A total of 161 participants (87 men and 74 women, average age = 20.26 ± 8.79 years, ranging from 5 to 51 years old) completed all examinations. Three participants were excluded due to their inability to complete the required examinations. There were significant differences between the amblyopic and the fellow eyes in terms of SER, best-corrected visual acuity, AULCSF, log BCEA, and the eccentricity of the preferred retinal locus (all P < 0.001). Both the amblyopic and the fellow eyes exhibited fixation stability deficits and eccentric fixation. The regression model showed that fixation stability in the amblyopic eye (log BCEA) was significantly associated with age, AULCSF of the amblyopic eye, AULCSF-IOD, eccentricity of the amblyopic eye, and log BCEA of the fellow eye (all P < 0.05). Fixation stability in the fellow eye (log BCEA) was significantly associated with eccentricity of the fellow eye, and log BCEA of the amblyopic eye (all P < 0.05). Conclusions Eccentric fixation and fixation stability deficits were observed in both the amblyopic and the fellow eyes, with fixation stability in both eyes being correlated with the eccentricity of the preferred retinal locus. These findings suggest that in the clinical management of amblyopia, attention should be given to the fixation stability and fixation characteristics of both the amblyopic and fellow eyes.

Characterizing the Preferred Retinal Locus and Fixation Stability in Diabetic Macular Ischemia: A One-Year Study

“…Moreover, eyes with DMI had their PRL very close to the EFL (0.18 ± 0.14°), far less than those with advanced ARMD (5.15 ± 3.31°) [ 29 ], and none of them fulfilled the criterion of eccentric fixation (≥2°) [ 28 ]. Together, these findings corroborate the proposal that fixation stability is positively correlated with the eccentricity distance between PRL and EFL [ 16 , 22 , 28 , 29 , 34 ]. They also indicate that DMI eyes have relatively stable fixation stability, and eccentric fixation is rarely seen.…”

Characterizing the Preferred Retinal Locus and Fixation Stability in Diabetic Macular Ischemia: A One-Year Study

“…Moreover, eyes with DMI had their PRL very close to the EFL (0.18 ± 0.14°), far less than those with advanced ARMD (5.15 ± 3.31°) [ 29 ], and none of them fulfilled the criterion of eccentric fixation (≥2°) [ 28 ]. Together, these findings corroborate the proposal that fixation stability is positively correlated with the eccentricity distance between PRL and EFL [ 16 , 22 , 28 , 29 , 34 ]. They also indicate that DMI eyes have relatively stable fixation stability, and eccentric fixation is rarely seen.…”

Evaluation of the Correlation of Reading Ability and Fixation Status in Patients With Neovascular Age-Related Macular Degeneration

“…The microperimeter recorded eye movements at a sampling rate of 30 Hz. During the measurement, the MP-3 uses auto-tracking and auto-alignment technologies to enhance measurement accuracy [ 19 ]. The FS was defined by the percentage of fixation points located within a circle of diameter 2°, centered on all fixation points [ 20 ].…”

Abnormal Fixational Eye Movements in Ophthalmic Disease: Implications for Visual Function and Clinical Assessment

“…While many studies have found normal levels of fixation stability in the fellow eye of amblyopia patients [ 21 , 53 , 54 , 58 , 59 ], oculomotor abnormalities can occur in both the amblyopic and the fellow eye [ 22 , 60 , 61 ]. In fact, some of the abnormalities occur simultaneously in both eyes [ 62 ], suggesting the role of a central mechanism.…”

“…In patients where a very stable PRL has not been established, increased eye movements could reflect adaptive behaviors aimed at trying to locate a patch of retina that supports clear vision [ 101 ]. However, large lesions cause PRLs to be established further from central fixation, and the farther a gaze position is from central fixation, the less stable the resulting fixation [ 30 , 61 , 102 , 103 ]. Similarly, the farther the PRL is from the margins of the central lesion, the less stable the resulting fixation [ 30 ] (see also [ 61 ] for similar findings in amblyopia).…”

“…However, large lesions cause PRLs to be established further from central fixation, and the farther a gaze position is from central fixation, the less stable the resulting fixation [ 30 , 61 , 102 , 103 ]. Similarly, the farther the PRL is from the margins of the central lesion, the less stable the resulting fixation [ 30 ] (see also [ 61 ] for similar findings in amblyopia). PRLs can develop in any quadrant of the retina, with similar fixation stabilities across PRLs in different quadrants [ 104 , 105 ].…”

Characterizing the Preferred Retinal Locus and Fixation Stability in Diabetic Macular Ischemia: A One-Year Study

“…Moreover, eyes with DMI had their PRL very close to the EFL (0.18 ± 0.14°), far less than those with advanced ARMD (5.15 ± 3.31°) [ 29 ], and none of them fulfilled the criterion of eccentric fixation (≥2°) [ 28 ]. Together, these findings corroborate the proposal that fixation stability is positively correlated with the eccentricity distance between PRL and EFL [ 16 , 22 , 28 , 29 , 34 ]. They also indicate that DMI eyes have relatively stable fixation stability, and eccentric fixation is rarely seen.…”

Evaluation of the Correlation of Reading Ability and Fixation Status in Patients With Neovascular Age-Related Macular Degeneration

“…The microperimeter recorded eye movements at a sampling rate of 30 Hz. During the measurement, the MP-3 uses auto-tracking and auto-alignment technologies to enhance measurement accuracy [ 19 ]. The FS was defined by the percentage of fixation points located within a circle of diameter 2°, centered on all fixation points [ 20 ].…”

Abnormal Fixational Eye Movements in Ophthalmic Disease: Implications for Visual Function and Clinical Assessment

“…While many studies have found normal levels of fixation stability in the fellow eye of amblyopia patients [ 21 , 53 , 54 , 58 , 59 ], oculomotor abnormalities can occur in both the amblyopic and the fellow eye [ 22 , 60 , 61 ]. In fact, some of the abnormalities occur simultaneously in both eyes [ 62 ], suggesting the role of a central mechanism.…”

“…In patients where a very stable PRL has not been established, increased eye movements could reflect adaptive behaviors aimed at trying to locate a patch of retina that supports clear vision [ 101 ]. However, large lesions cause PRLs to be established further from central fixation, and the farther a gaze position is from central fixation, the less stable the resulting fixation [ 30 , 61 , 102 , 103 ]. Similarly, the farther the PRL is from the margins of the central lesion, the less stable the resulting fixation [ 30 ] (see also [ 61 ] for similar findings in amblyopia).…”

“…However, large lesions cause PRLs to be established further from central fixation, and the farther a gaze position is from central fixation, the less stable the resulting fixation [ 30 , 61 , 102 , 103 ]. Similarly, the farther the PRL is from the margins of the central lesion, the less stable the resulting fixation [ 30 ] (see also [ 61 ] for similar findings in amblyopia). PRLs can develop in any quadrant of the retina, with similar fixation stabilities across PRLs in different quadrants [ 104 , 105 ].…”

Characterizing the Preferred Retinal Locus and Fixation Stability in Diabetic Macular Ischemia: A One-Year Study

“…Moreover, eyes with DMI had their PRL very close to the EFL (0.18 ± 0.14°), far less than those with advanced ARMD (5.15 ± 3.31°) [ 29 ], and none of them fulfilled the criterion of eccentric fixation (≥2°) [ 28 ]. Together, these findings corroborate the proposal that fixation stability is positively correlated with the eccentricity distance between PRL and EFL [ 16 , 22 , 28 , 29 , 34 ]. They also indicate that DMI eyes have relatively stable fixation stability, and eccentric fixation is rarely seen.…”

Evaluation of the Correlation of Reading Ability and Fixation Status in Patients With Neovascular Age-Related Macular Degeneration

“…The microperimeter recorded eye movements at a sampling rate of 30 Hz. During the measurement, the MP-3 uses auto-tracking and auto-alignment technologies to enhance measurement accuracy [ 19 ]. The FS was defined by the percentage of fixation points located within a circle of diameter 2°, centered on all fixation points [ 20 ].…”

Abnormal Fixational Eye Movements in Ophthalmic Disease: Implications for Visual Function and Clinical Assessment

“…While many studies have found normal levels of fixation stability in the fellow eye of amblyopia patients [ 21 , 53 , 54 , 58 , 59 ], oculomotor abnormalities can occur in both the amblyopic and the fellow eye [ 22 , 60 , 61 ]. In fact, some of the abnormalities occur simultaneously in both eyes [ 62 ], suggesting the role of a central mechanism.…”

“…In patients where a very stable PRL has not been established, increased eye movements could reflect adaptive behaviors aimed at trying to locate a patch of retina that supports clear vision [ 101 ]. However, large lesions cause PRLs to be established further from central fixation, and the farther a gaze position is from central fixation, the less stable the resulting fixation [ 30 , 61 , 102 , 103 ]. Similarly, the farther the PRL is from the margins of the central lesion, the less stable the resulting fixation [ 30 ] (see also [ 61 ] for similar findings in amblyopia).…”

“…However, large lesions cause PRLs to be established further from central fixation, and the farther a gaze position is from central fixation, the less stable the resulting fixation [ 30 , 61 , 102 , 103 ]. Similarly, the farther the PRL is from the margins of the central lesion, the less stable the resulting fixation [ 30 ] (see also [ 61 ] for similar findings in amblyopia). PRLs can develop in any quadrant of the retina, with similar fixation stabilities across PRLs in different quadrants [ 104 , 105 ].…”