الفهرس 
List of figuresOnly 14 pages are availabe for public view
 |  | from | 144 |  |  |
| | | from | 144 | | |
Abstract
Posterior dislocation of lens fragments into the vitreous is a fairly uncommon complication of cataract surgery with an incidence of approximately 0.2% to 1.5%. Proper management both intraoperatively and postoperatively is essential in reducing the risk of further complications. Management usually includes pars plana vitrectomy (PPV) to improve visual acuity and reduce intraocular inflammation and pressure.
Optimal vitrectomy timing is unknown, and the effect of timing on outcomes is controversial. Some favor early vitrectomy within a week or two of, or even the same day as, cataract surgery. Others prefer to wait and see, performing an early PPV only when clinically indicated; for example, if the patient had increased intraocular pressure (IOP) unresponsive to medication and/or a severe inflammatory response or in presence of associated co-morbidities as retinal detachment.
The aim of this prospective non randomized case series was to determine outcomes of prompt, early and late pars plana vitrectomy for dislocated lens fragments and/ or IOL in complicated phacoemulsification, and to correlate functional outcomes with ultrastructural findings detected by OCT of the macula, the optic disc and the anterior segment. We studied correlation between clinical outcomes and ultrastructural changes detected by OCT of the macula, the optic disc and the anterior segment. The clinical outcomes included UCVA, BCVA, IOP and postoperative complications. The OCT outcomes included central foveal thickness, average foveal thickness, macular volume, RNFL thickness, GCL thickness, C/D ratio, CCT, ACD and AC angle. In addition, we tried to determine the prognostic factors in such cases, with special emphasis on the timing of PPV on one hand, and the use of intravitreal ultrasound emulsification on the other hand.
In our study, 35 eyes of 35 patients fulfilling the inclusion criteria were studied and followed up for 12 months. A control group of 85 eyes of 67 patients -matching the demographic criteria and the axial length with the study group- were included for comparative analysis. We used 23-gauge transconjunctival PPV system in all cases. In cases necessitated the use of 20-gauge phacofragmatome, one sclerotomy was enlarged by a MVR blade.
Our results showed high statistically significant difference (p <0.01) between cases and controls in both UCVA and BCVA during the whole follow up visits The incidence of early and late postoperative complications was significantly higher in the study group. Regarding OCT-macula changes, there was a high significant difference between both groups (p value <0.01). Along the follow up period, both groups showed improvement in OCT-macula findings
In this study and according to the timing of PPV intervention in relation to the cataract surgery, 9 eyes (25.71%) subjected to prompt or same-setting PPV, 12 eyes (34.29%) had PPV early within one week after the cataract surgery (average 3.5 days). The remaining 14 eyes (40%) had late PPV more than one week after the cataract surgery (average 12.4 days, range 8-32 days). We found that there was statistically high significant difference (p <0.01) in clinical outcomes among prompt, early and late subgroups. In order to detect the statistical significance difference between every two subgroups, the data was analyzed using one way ANOVA- Post Hoc multiple comparison. We detected that the significant difference was present between prompt and late subgroups, while there was no significant difference between prompt and early subgroups on one hand or between early and late subgroups on the other hand
In our study, analysis of the OCT-macula findings showed that there was statistically high significant difference among the three subgroups in both central foveal thickness and macular volume. However, there was no significant difference in the average macular thickness. On the other hand, there was no detected significant difference among the three subgroups in any parameters of neither OCT-glaucoma profile nor anterior segment OCT changes.
In our study, the surgical techniques built on an existing evidence of the efficacy and efficiency of 23-gauge transconjunctival PPV system in managing such complication. We classified the study group into two categories, the vitreous cutter only subgroup which included 14 eyes (40%) where the use of intravitreal ultrasound emulsification was not indicated, and the phacofragmatome subgroup (21 eyes, 60%).
In this study, we reported better visual outcome in the vitreous cutter only subgroup compared to the phacofragmatome subgroup. Both UCVA and BCVA showed a high significant difference in all follow up visits.
One third of eyes in the 2nd subgroup had poor visual outcome, while only one eye (7.1%) in the 1st subgroup had the same outcome. All postoperative complications occurred with higher incidence in the phacofragmatome subgroup with incidence of CME was 28.6% compared to only 14.2% in the vitreous cutter subgroup
Conclusion
Timing of PPV is an important factor affecting both clinical and OCT-outcomes in dislocated nuclear fragments and IOL. The prompt PPV was associated with the best outcome followed by the early PPV. Cases in which, intravitreal ultrasound emulsification was indicated, had poorer prognostic outcome.