الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
Summary and Conclusion
The aim of this study was to compare the corneal topographic changes after 23-guage transconjunctival sutureless vitrectomy (TSV) to those occuring after standard 20-guage pars plana vitrectomy (PPV).
This study included 40 patients who were indicated to undergo primary vitrectomy for vitreoretinal pathologies. They were randomly divided into 2 groups;
- Group 1 included 20 patients in whom 23-gauge TSV was done.
- Group 2 included 20 patients in whom 20-gauge PPV was done.
Patients with history of corneal trauma, scars or haze, previous ocular surgery, corneal disease found upon slit lamp examination or corneal topography, conjunctival or scleral scarring, IOP outside the range of 6-26 mmHg, postoperative significant corneal opacity, and a failed surgery were excluded from the study.
Preoperative evaluation was done in the form of complete history, complete ophthalmological examination and Corneal topography using the Pentacam.
All cases were evaluated postoperatively by corneal topography using the Pentacam which was obtained one week, one month and three months postoperative and intraocular pressure (IOP) measurement. The patient’s medical records were reviewed and surgical and ocular parameters were recorded.
Postoperative anterior corneal elevation showed a significant (P<0.05) increase in group 2 compared to the preoperative elevation, and in group 2 in comparison to group1. However, group 1 showed a non significant increase at 1 week, 1 month and 3 months.
At 3 months, anterior corneal elevation showed significant (P<0.05) decrease compared to 1-month postoperatively in group 2, but was non-significant in group 1.
Postoperative posterior corneal elevation showed a significant increase in both groups in comparison to the preoperative elevation, but with a significant increase at 1-week and 1-month compared to at 3 months after surgery. At 3 months, the posterior elevation showed significant decrease more in group 2 in relation to the 1month postoperative corneal elevation.
Patients in group 1 showed a non significant change in postoperative corneal astigmatism at 1 week, 1 month and 3 months; whereas the increased corneal astigmatism in group 2 was significant at 1-week, 1month and 3 months compared to preoperative corneal astigmatism.
Moreover, postoperative corneal astigmatism was significantly increased in group 2 in comparison to the changes that occurred in group 1.
Corneal thickness showed a non-significant change (P>0.05) at 1 week, 1 month and 3 months compared to the preoperative thickness, in the 2 groups. Furthermore, there was a non-significant difference between the 2 groups throughout the period of follow up.
There was a significant difference in the mean operative time. Group 1 mean operative time was 43.6 ± 15.3 minutes, while group 2 mean operative time was 73.5 ± 11.3 minutes. Regarding the complications of surgeries, no intra-operative complications occurred in either group.
from this study we conclude that;
- 23 gauge TSV does not induce significant corneal topographic changes. It appears to be a good alternative for standard 20-gauge PPV.
- Posterior corneal elevation shows to be more sensitive parameter in topographic changes than anterior corneal elevation.
- The pachymetry changes are said to be of no significance according to this study.
- Pentacam is a reliable investigative tool for evaluating corneal topographic changes and measuring corneal thickness following various vitreoretinal surgeries.
from this study we recommend the following:
- With the increasing development of vitreoretinal techniques and instruments, attention should be paid towards the corneal changes aiming at faster and better postoperative visual rehabilitation.
- Using posterior corneal elevation maps as a more sensitive indicator for corneal topographic changes.
- 23 gauge TSV is a good alternative for standard 20-gauge PPV.