Orthoptic Changes Following Photorefractive Keratectomy

This study has been completed.
Information provided by:
Shahid Beheshti Medical University
ClinicalTrials.gov Identifier:
First received: January 19, 2011
Last updated: NA
Last verified: April 2008
History: No changes posted
Purpose: To detect orthoptic changes in patients undergoing photorefractive keratectomy (PRK). Method: This interventional case series was performed on 297 eyes of 150 patients who were candidates for PRK. Complete ophthalmic evaluations focusing on orthoptic examinations were performed before and 3 months after PRK. Results: Before PRK, two (1.3%) patients had esotropia that remained unchanged postoperatively. However, 3 (2%) patients had distance exotropia preoperatively which improved after PRK. Of 12 cases (8%) with preoperative exotropia at near, 3 (2%) cases became orthophoric. Six patients (4%) developed postoperative near exotropia. A significant reduction in means of convergence and divergence amplitudes (P<0.001) and a meaningful increase in mean of near point of convergence (NPC) (P<0.006) were noticed after PRK. A reduction of ≥10 PD in convergence amplitude and ≥5 PD in divergence amplitude were detected in 10 and 5 patients, respectively. Four patients had an preoperative NPC>10 cm which was not changed by the surgery. Out of 9 (6%) patients with baseline stereopsis >60 seconds of arc, 2 (1.33%) cases showed an improvement in stereopsis following PRK. None of the patients complained of postoperative diplopia. Conclusion: Eye deviation in patients undergoing PRK may improve or remain unchanged after operation and postoperative deviations can develop following this surgery. Diminishing of fusional amplitude and increasing of NPC as well as improving of stereopsis may also happen after PRK. Therefore, a preoperative orthoptic examination in patients with any concerning histories and/or motility issues on routine exam is recommended before performing PRK.

Condition Intervention Phase
Orthoptic Changes
Procedure: Kerato refractive Surgery
Phase 3

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Primary Purpose: Supportive Care
Official Title: Orthoptic Changes Following Photorefractive Keratectomy

Further study details as provided by Shahid Beheshti Medical University:

Primary Outcome Measures:
  • orthoptic changes [ Time Frame: before and after KRS ] [ Designated as safety issue: No ]
    Prism / (deviation)

Secondary Outcome Measures:
  • VA , Streopsis , deviation , fusion , NPC [ Time Frame: before and after KRS ]
    Snellen , Titmus, prism, ruler

Study Start Date: April 2008
Study Completion Date: April 2009
Primary Completion Date: January 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Kerato refractive Surgery Procedure: Kerato refractive Surgery
This interventional case series was performed on 297 eyes of 150 patients who were candidates for PRK. Complete ophthalmic evaluations focusing on orthoptic examinations were performed before and 3 months after PRK.


Ages Eligible for Study:   18 Years to 59 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

>18 yrs / refractive errors / with consent

Exclusion Criteria:

< 18 / corneal opacity - keratoconus

Dry eye / diabetes / collages vacuolar disease

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Please refer to this study by its ClinicalTrials.gov identifier: NCT01279993

Iran, Islamic Republic of
Labbafinejad medical center
Tehran, Iran, Islamic Republic of
Sponsors and Collaborators
Shahid Beheshti Medical University
Principal Investigator: zhaleh rajavi, Assistant Professor Imam Hossein Medical Center
  More Information

No publications provided

Responsible Party: Zhale Rajavi, Ophthalmic Research center
ClinicalTrials.gov Identifier: NCT01279993     History of Changes
Other Study ID Numbers: 8659 
Study First Received: January 19, 2011
Last Updated: January 19, 2011
Health Authority: Iran: Ethics Committee

ClinicalTrials.gov processed this record on February 11, 2016