Relative mydriasis after photorefractive keratectomy.
OBJECTIVE
To report the incidence of anisocoria after unilateral excimer laser photorefractive keratectomy (PRK) for myopia and subsequent corticosteroid therapy in a retrospective and prospective study and to explore possible etiologies.


METHODS
The horizontal pupil diameter was determined in 6 patients (6 eyes) at 21.8 +/- 12.6 months after unilateral wide-field excimer laser PRK (retrospective group) as well as in 8 consecutive patients (8 eyes) before and 3.4 +/- 2.9 months after unilateral PRK (prospective group). The Schwind-Keratom wide-field excimer laser was used. Measurements were done in an examination room using Rosenbaum card comparison pupillometry and with a Goldmann perimeter at 31.5 asb. In the prospective group, the effect of fitting a hard contact lens of zero diopter power and the application of 0.1% pilocarpine were evaluated.


RESULTS
Relative mydriasis was present in all treated eyes and the difference in pupil diameter between the two eyes measured 0.25 to 1.75 mm (retrospective group: +0.56 +/- 0.82 mm; prospective group: +0.72 +/- 0.29 mm). At the time of pupil measurement, the retrospective group had a significantly longer mean postoperative follow-up (21 mo) than the prospective group (3.4 mo) and significantly more eyes still received topical corticosteroid treatment (retrospective group, 1 of 6 eyes; prospective group, 7 of 8 eyes). The amount of anisocoria did not correlate with the applied laser energy, ablation depth, or refractive change, but showed a negative correlation with increasing time after PRK. Neither hard contact lens fitting nor pilocarpine 0.1% reduced the amount of anisocoria significantly.


CONCLUSIONS
Unilateral PRK with wide-field excimer laser ablation and subsequent application of topical corticosteroids regularly resulted in a relative pupillary mydriasis. Neither an altered corneal profile nor parasympathetic denervation is responsible for this. Weakening of the pupillary sphincter of the treated eye may cause this phenomenon.
Geerling
G
G
Department of Ophthalmology, Medical University Lübeck, Germany. geerlingg@aol.com
Neppert
B
B
Wirbelauer
C
C
Laqua
H
H
D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D015875:Anisocoria / Q000188:drug therapy / Q000209:etiology; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D004008:Diclofenac / Q000627:therapeutic use; D005938:Glucocorticoids; D006801:Humans; D054018:Lasers, Excimer; D008875:Middle Aged; D015878:Mydriasis / Q000188:drug therapy / Q000209:etiology*; D009216:Myopia / Q000601:surgery; D009883:Ophthalmic Solutions / Q000627:therapeutic use; D018903:Photorefractive Keratectomy / Q000009:adverse effects*; D011239:Prednisolone / Q000031:analogs & derivatives / Q000627:therapeutic use; D011446:Prospective Studies; D011680:Pupil / Q000187:drug effects; D012189:Retrospective Studies; D014792:Visual Acuity
D000893:Anti-Inflammatory Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D005938:Glucocorticoids; D009883:Ophthalmic Solutions; D004008:Diclofenac; C009935:prednisolone acetate; D011239:Prednisolone