Floaterectomy Versus Conventional Pars Plana Vitrectomy For Vitreous Floaters
Digital Journal of Ophthalmology 2007
Volume 13, Number 2
July 13, 2007
To compare the efficacy and complication rate between floaterectomy and conventional pars plana vitrectomy for symptomatic floaters associated with PVD.
We compared floaterectomy to conventional vitrectomy in two case series. 11 phakic eyes of 8 patients, average age 61, underwent phacoemulsification, posterior curvilinear capsulorhexis, deep anterior vitrectomy, and posterior chamber intraocular lens insertion. 20 phakic eyes of 20 patients, average age 64, underwent conventional vitrectomy surgery.
Floaterectomy and pars plana vitrectomy were both 100% successful in removing symptomatic floaters. There was 1 retinal detachment in the floaterectomy group and 2 in the conventional vitrectomy group. One patient had cystoid macula oedema after floaterectomy which resolved.
Floaterectomy offers a new approach to the removal of vitreous floaters but may carry as many risks as benefits over pars plana vitrectomy.
floaters, posterior vitreous detachment, vitrectomy, phacofloaterectomy, retinal detachment.
|Vitreous floaters represent one of the most common presentations to hospital eye services. A survey of optometrists in 2002 suggested that an average of 14 patients per month per optometrist presented with symptoms of floaters in the UK.(1)|
Although floaters can be due to vitreous hemorrhage, asteroid hyalosis, uveitis, amyloid or syneresis, the majority of symptomatic patients show separation of the posterior vitreous (PVD), classically with a Weiss ring where the vitreous has avulsed from the optic disc. This gives rise to a large central floater that can be visually significant, particularly in younger patients whose occupations involve reading or use of computer screens.
With the advent of vitrectomy surgery it has become possible to remove vitreous floaters.(2, 3, 4) Most patients experience a gradual reduction in the awareness of floaters following PVD, but some are persistently annoyed by them and therefore seek intervention.
Many vitreoretinal surgeons are reluctant to perform pars plana vitrectomy (PPV) for floaters given the risk of retinal detachment and secondary cataract formation.(5, 6, 7, 8, 9, 10) The severity of symptoms may also be underestimated. Although Nd:yag vitreolysis has shown promise as a non-surgical treatment it only has a one-third success rate in reducing symptoms, is best used for well-suspended floaters, and carries a risk of precipitating cystoid macular oedema.(11, 12) Mossa and Delaney et al. described a new approach in 2002 which they coined “floaterectomy”: phacoemulsification of the lens is followed by a posterior capsulorhexis and deep anterior vitrectomy before posterior chamber lens insertion. Their series of 10 eyes in 6 patients had a symptom resolution in 80%, with 1 patient developing cystoid macular edema and persistent floaters, which the authors attributed to undiagnosed uveitis.(13)
|Materials and Methods|
|A retrospective case analysis of all patients undergoing surgery for floaters over a 5 year period at the Norfolk and Norwich University Hospital was performed. Data was entered into Excel® for analysis. Cases were grouped into those who underwent conventional pars plana vitrectomy and those who had phacoemulsification of the lens with deep anterior vitrectomy and intraocular lens insertion. Only patients in whom the presence of a posterior vitreous detachment could be established (by detection of a separated posterior hyaloid membrane or Weiss ring on slit-lamp biomiscoscopy) underwent floaterectomy. An inspection of the peripheral retina at the end of each case was not performed in this group.|
The remaining patients underwent 3-port PPV, using the Biom® viewing system and 23-guage instruments. An inspection of the peripheral retina for tears was conducted at the end of each case. Prophylactic cryotherapy to the sclerostomies was not performed.
All surgery was performed or supervised by the same surgeon. No patients were lost to follow-up. All were examined at one day, two weeks and six months post-operatively.
|Pars Plana Vitrectomy Group|
20 phakic eyes of 20 patients, average age 64, underwent conventional vitrectomy surgery. The mean pre-operative best corrected Snellen visual acuity (BCVA) was 6/15. Five required subsequent cataract surgery for symptomatic lens opacity and declining vision. One patient had an early (next day) retinal detachment requiring vitrectomy revision and gas endotamponade.
Mean BCVA at discharge was 6/6, with a distribution from 6/5 to 6/12. All patients (100%) were floater-free at discharge. This group averaged 7 post-operative visits each.
11 phakic eyes of 8 patients, average age 61, underwent phacoemulsification, posterior curvilinear capsulorhexis, deep anterior vitrectomy, and posterior chamber intraocular lens insertion. Mean pre-operative visual acuity was also 6/15. All eyes had at least one plus nuclear-sclerotic cataract. One eye developed a macular-on retinal detachment after 4 months, successfully treated with PPV and gas endotamponade. Another eye developed cystoid macular edema which resolved with a month course of topical dexamethasone 0.1%. All patients (100%) were floater-free at discharge with a mean BCVA of 6/6, mode 6/5. The average number of post-operative visits was 5.
|This is the first dual case series comparison of conventional vitrectomy and floaterectomy for the treatment of symptomatic floaters. Both approaches appear to have a high success rate, both in terms of symptom resolution and visual acuity. A 5-10% incidence of retinal detachment in both groups is surprisingly high, but given the small sample size of this pilot study it cannot be concluded that the procedure necessarily has a higher rate or detachment over conventional vitrectomy. Floaterectomy however has many advantages over conventional vitrectomy:|
1. The need for subsequent removal of secondary cataract in a vitrectomised eye is obviated.
2. A greater risk of complications may exist when cataract surgery is performed in vitrectomised eyes, depending on the surgeon’s familiarity with this procedure.(14, 15, 16) The degree of zonular instability appears to be related to the extent of gel removed, and may therefore be less in the case of deep anterior vitrectomy than in conventional pars plana vitrectomy.(7)
3. The procedure does not require sclerostomies or conjunctival peritomy as an anterior-chamber infusion is used.
4. Visual rehabilitation is more rapid with fewer post-operative visits and improved cost-utility.
5. Topical and intracameral anaesthesia is possible.
6. Development of posterior capsular thickening in the visual axis is very unlikely.
There are also disadvantages:
1. Often a clear crystalline lens will be removed. In younger patients the interval between vitrectomy and visually significant cataract formation tends to be longer than in more elderly patients.
2. Placement of the posterior chamber lens implant “in the bag” is technically more difficult. Use of the anterior vitrector through the posterior capsulorhexis in the presence of a capsule tear may lead to extension of this tear. Additionally, the posterior window must be large enough to permit adequate use of the vitreous cutter but small enough to allow for a stable posterior chamber IOL. Where possible the optic of the IOL would ideally be “captured” by the posterior capsulorhexis, ensuring good centration.
3. The risk of endophthalmitis is theoretically greater.
4. Biometry may be less accurate in an eye which is to become vitrectomised per-operatively.
5. Retinal tears may be less likely to be detected if there is corneal oedema or obscuration from the intraocular lens. It is suggested that indirect indentation ophthalmoscopy be performed prior to IOL implantation. It is also recommended that the procedure only be performed by a vitreoretinal specialist.
6. Floaterectomy cannot remove the same amount of vitreous and therefore floaters as conventional PPV, partly due to the inability to perform indentation-assisted trimming of the vitreous base. However most symptomatic floaters are posteriorly situated in the gel and would be adequately removed.
It is likely that in coming years with an aging population the rate of referral of patients with symptomatic floaters will increase. Given that surgical treatment appears to be very successful and relatively safe, and that the majority of these patients would eventually require cataract surgery anyway, it will become increasingly difficult for the ophthalmologist to refuse such intervention. As always, careful counselling with full explanation of the risk/benefit profile is mandatory, particularly for a new technique that has not undergone rigorous randomized controlled trials. Further work is necessary to identify newer and safer ways to remove floaters, such as intra-vitreal injection of hyaluronidase analogues and use of transconjunctival sutureless 25-guage vitrectomy systems with high cut-rates, but in the absence of this, the above case series comparison does offer preliminary encouragement in the use of the floaterectomy technique.
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