Dear Editor,
We read with great interest the study by Erbezci et al.,1 which examined the topographic and functional characteristics of preferred retinal loci (PRLs) in juvenile macular dystrophy using scanning laser ophthalmoscopy and microperimetry. The age-stratified analysis and fixation-tracking methodology provide meaningful contributions to the literature on eccentric fixation in inherited maculopathies. However, several aspects merit closer scrutiny to clarify the implications for low-vision rehabilitation.
The authors interpret the age-related shift in PRLs from nasal to superior locations as evidence of cortical adaptation. However, this inference assumes a unidirectional maturational trajectory rather than considering the role of structural lesion dynamics. Because younger patients in the cohort also exhibited significantly larger lesion sizes, the posterior anatomical displacement of PRLs may be a consequence of constrained viable retinal area rather than active cortical optimization.2 Clinically, this distinction matters because spontaneous superior locus acquisition may not reflect training potential but rather lesion permissiveness, which may vary between individuals.
Additionally, the interpretation that superiorly located PRLs confer functional advantages for reading and mobility warrants more cautious framing. While lower visual field scotomas (associated with superior loci) can indeed facilitate tasks requiring downward gaze, the study did not assess near-vision outcomes such as reading speed, critical print size, or text navigation accuracy. Without these data, the presumed functional superiority remains speculative.3 A more robust conclusion would require integrating continuous-text performance metrics that directly quantify task-relevant visual efficiency.
Moreover, although fixation stability was quantified via dispersion metrics, the clinical relevance of the measured values remains ambiguous. The study did not clarify whether the reported fixation instability of 2.15±1.43 degrees crosses any threshold predictive of rehabilitation responsiveness. In patients undergoing eccentric viewing training, fixation stability below 2° has been associated with better functional gains.4 Without such a reference point, the measured stability values are difficult to translate into practical decision-making for visual therapy planning.
The observed correlation between PRL-fovea distance and lesion area reinforces the anatomical basis of eccentric fixation, yet its application to rehabilitation remains underdeveloped. Specifically, it remains unclear whether PRL relocation is feasible when eccentricity exceeds certain angular thresholds. Identifying a critical eccentricity limit beyond which perceptual and oculomotor recalibration becomes less effective could aid in triaging candidates for intensive vision training protocols.5
In summary, while this study advances our anatomical understanding of PRL characteristics in juvenile macular dystrophy, its translational contribution would be strengthened by linking structural metrics to task-specific visual outcomes and therapeutic thresholds. Clarifying these relationships may inform individualized strategies for optimizing residual vision in young patients navigating educational and occupational demands.
