Abstract
Purpose: :
Patients with normal vision and with ocular prostheses with longstanding ptosis have been observed to develop compensatory ipsilateral frontalis muscle overaction. Among the factors that could drive the response in the sighted eye are vision, corneal sensation, and eyelid proprioception. In patients with an ocular prosthesis, vision and corneal sensation have been eliminated, suggesting that proprioception drives the observed frontalis contraction in these individuals. In this study, we investigated the role of vision, corneal sensation, and eyelid proprioception in the response to acute ptosis in patients with and without ocular prostheses.
Methods: :
IRB approval was obtained. Photographs were taken for 25 individuals with normal eye exams in the following scenarios: no intervention, small weight attached to central pre-tarsal right upper eyelid, proparacaine drop plus small weight in the right eye, and hyperopic soft contact lens, proparacaine drop, and small weight in the right eye. The same sequence was repeated for the left eye. Photographs were taken for 15 individuals with an ocular prosthesis in the following settings: no intervention, small weight attached to the upper eyelid of the anophthalmic eye, and proparacaine drop plus small weight in the anophthalmic eye. The same sequence was repeated for the sighted eye. The ratio of MRD2 to brow height was determined by two blinded ophthalmologists. The average of the measurements between the two observers was determined, and the ratios between the baseline group and each intervention were compared.
Results: :
Statistical analysis has been performed for 12 of the 25 patients with normal eye exams. In these 12 patients a trend of a decrease in brow height with weight, proparacaine, and contact lens compared to weight only was observed (p=0.30), but it did not return to baseline height (p=0.53). Frontalis contraction appeared to be maintained in acute ptosis in anophthalmic patients.
Conclusions: :
Frontalis contraction appears to be maintained in acute ptosis in patients with an anesthetized cornea and blurred vision, suggesting that eyelid proprioception may drive the reaction. Additional statistical analysis will be performed on the collected data to further evaluate the contributions of proprioception, vision, and corneal sensation to frontalis contraction. Understanding the mechanisms of brow elevation in ptosis is imperative for the prevention and treatment of adverse clinical and cosmetic effects.