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Relative mydriasis after photorefractive keratectomy
G Geerling1, B Neppert, C Wirbelauer
1Department of Ophthalmology, Medical University Lübeck, Germany. geerlingg@aol.com
Journal of Refractive Surgery (Thorofare, N.J. : 1995)
|February 29, 2000
Summary
Unilateral photorefractive keratectomy (PRK) for myopia can cause relative mydriasis (pupil dilation) in the treated eye. This pupillary abnormality, likely due to sphincter weakening, may persist after treatment.
Area of Science:
- Ophthalmology
- Corneal Surgery
- Ocular Physiology
Background:
- Anisocoria, or unequal pupil size, can be a side effect of ocular procedures.
- Excimer laser photorefractive keratectomy (PRK) is used to correct myopia.
- Corticosteroid therapy is often prescribed post-PRK.
Purpose of the Study:
- To determine the incidence of anisocoria following unilateral excimer laser PRK for myopia.
- To investigate the role of corticosteroid therapy in post-PRK anisocoria.
- To explore potential causes of anisocoria after PRK.
Main Methods:
- Retrospective and prospective study design.
- Measured horizontal pupil diameter in patients undergoing unilateral wide-field excimer laser PRK.
- Utilized pupillometry and Goldmann perimetry; evaluated contact lens and pilocarpine effects in a prospective cohort.
Main Results:
- All treated eyes exhibited relative mydriasis.
- Anisocoria ranged from 0.25 to 1.75 mm, with a mean of +0.72 mm in the prospective group.
- Anisocoria showed a negative correlation with time post-PRK and was not significantly reduced by interventions.
Conclusions:
- Unilateral PRK with wide-field ablation and corticosteroids commonly leads to relative pupillary mydriasis.
- Neither corneal profile changes nor parasympathetic denervation explain the mydriasis.
- Weakening of the pupillary sphincter is the suspected cause of this persistent anisocoria.