Vitreous floaters frequently give rise to visual symptoms. The most common causes are vitreous liquefaction, posterior vitreous detachment (PVD),1 and asteroid hyalosis.2 In a small percentage of patients, the visual symptoms can be significant, necessitating surgical intervention. The neodymium:YAG (Nd:YAG) laser3 and pars plana vitrectomy (PPV) have been advocated as treatment for vitreous floaters in symptomatic patients.
Cataract and floaters frequently coexist in the same patient. The choice of treatment is limited to cataract extraction alone or with simultaneous or sequential 3-port PPV.4 We describe a 1-stage procedure to treat both cataract and floaters that combines phacoemulsification of the lens followed by an anterior vitrectomy via a posterior capsulorhexis.
Preoperatively, cyclopentolate 1% and phenylephrine 10% are administered every 20 minutes 1 hour before surgery.
After a peribulbar injection of 5 mL of lignocaine 2% is given with a 25-gauge needle, a clear corneal incision is made with a 2.75 mm keratome blade and a paracentesis formed in the adjacent quadrant. Viscoelastic material is injected into the anterior chamber, and a continuous anterior curvilinear capsulorhexis is created with a capsulorhexis forceps. After hydrodissection, phacoemulsification of the nucleus is done using a stop-and-chop or divide-and-conquer technique. Cortical lens matter is removed using a manual irrigation/aspiration system.
The anterior chamber and capsular bag are filled with viscoelastic material. With the posterior capsule under tension, a posterior curvilinear capsulorhexis 4.0 to 5.0 mm in diameter is performed in 3 steps: (1) A 30-gauge needle is introduced and a small radial tear made. (2) Viscoelastic material is injected again to tamponade vitreous presentation. (3) A capsulorhexis forceps is used to complete the capsulorhexis.
A bimanual anterior vitrectomy is performed. The bottle height and therefore the infusion rate are adjusted to allow sufficient vitreous displacement and prolapse, permitting adequate clearance of the central vitreous. The vitreous cutting tip is placed in the central vitreous cavity and not beyond or peripheral to the iris root to avoid stress to the peripheral retina.5 The vitreous opacities are engaged under direct microscopic visualization and removed. A thorough examination of the peripheral retina is performed by indirect ophthalmoscopy to check for retinal breaks.
The anterior chamber and the capsular bag are filled again with viscoelastic material. A foldable 6.0 mm silicone intraocular lens with poly(methyl methacrylate) haptics (SI-40, Allergan) is inserted in the bag and dialed. The IOL will rotate freely if no vitreous is present. After the viscoelastic material is removed, the corneal incisions are checked for the presence of vitreous strands. The anterior chamber is reformed with a balanced saline solution, and the corneal wound is hydrated. A subconjunctival injection of betamethasone (Betnesol®) 2 mg and gentamicin 2 mg is given at the end of the procedure.
Between January 1998 and August 2000, a floaterectomy was performed in 10 eyes of 6 patients. The mean age of the 2 men and 4 women was 61 years (range 50 to 80 years) (Table 1) and the mean axial length, 25.5 mm (range 22.5 to 29.0 mm). Preoperatively, the vitreous floaters were considered to be the result of asteroid hyalosis and posterior detachment in 3 eyes and of posterior vitreous detachment only in 7 eyes. All patients provided informed consent.
The inclusion criteria were the presence of floaters causing severe symptoms for at least 3 months, co-existing symptomatic cataract, and patient motivation for surgical intervention. Exclusion criteria included a history of retinal detachment, diabetes mellitus, retinal disease, or intraocular inflammation.
Patients had a full ophthalmic examination including slitlamp biomicroscopy followed by direct and indirect ophthalmoscopy with indentation of the peripheral retina. Postoperative follow-up was at 1, 3, and 6 months.
Eight eyes improved from a best corrected visual acuity (BCVA) of 6/9 preoperatively to 6/6 postoperatively. Both eyes of patient 6 improved from a BCVA of 6/36 preoperatively to 6/18 postoperatively. In this patient, fluorescein angiography showed bilateral postoperative cystoid macular edema (CME). The visual acuity did not improve further despite a sub-Tenon's steroid injection, although the patient expressed satisfaction with her postoperative visual function. It is possible this patient had an unknown history of intermediate uveitis.
At the 6-month follow-up, 9 eyes had complete resolution of the symptoms of floaters. In patient 1, despite initial resolution, the floaters recurred at 3 months. Clinical examination revealed complete detachment of the posterior hyaloid face, indicating that only a partial detachment had been present at the time of surgery.
Floaters are the result of entoptic phenomena caused by condensed vitreous fibers, glial tissue of epipapillary origin that adheres to the posterior vitreous cortex.6 The perception of floaters in the visual field can cause significant visual disability. Centrovitreal opacities can also reduce visual acuity by impeding the visual axis.
Preoperative assessment of patients with floaters should include a thorough examination of the vitreous to establish the presence and position of the vitreous opacities, which can be classified as peripapillary or centrovitreal. The latter, because of their location, are more likely to cause visual symptoms. Detection of the presence of a complete detachment of the posterior vitreous face is essential. In patient 1, a complete PVD was incorrectly diagnosed and occurred postoperatively, causing a recurrence of symptoms. A surgically induced PVD can cause retinal breaks, increasing the risk of retinal detachment. With coexisting cataract and dense vitreous opacities, it may be difficult to confirm a PVD clinically and a B-scan7 appears to be mandatory. Preoperative indirect ophthalmoscopy with scleral indentation must also be performed to rule out the presence of peripheral retinal breaks. Other treatment options should be discussed with the patient before obtaining informed consent.
The Nd:YAG laser has been used to disrupt vitreous opacities in symptomatic patients.3 However, the presence of a coexisting cataract can make visualization of the opacities, and therefore the laser treatment, difficult. A greater application of energy is necessary in the presence of lenticular opacities. Furthermore, opacities in the posterior vitreous and lying close to the retina should not be treated by this method.
A 3-port PPV combined with cataract extraction has also been advocated to remove floaters in selected patients. The advantage of this technique is that any peripheral retinal break can be directly visualized and treated. Despite this, the risks of PPV include retinal detachment, macular pucker, endophthalmitis, and expulsive hemorrhage.
Floaterectomy is a 1-stage procedure that combines phacoemulsification of the lens and removal of vitreous opacities by an anterior vitrectomy. Small-incision surgery provides a controlled operating environment, reduces the operating time, and leads to rapid visual recovery. Intraoperative complications such as expulsive hemorrhage, endophthalmitis, and retinal detachment are minimized. A corneal incision avoids the use of scleral ports to access the posterior vitreous cavity and therefore eliminates the risk of entry-site breaks and subsequent retinal detachment. We stress the importance of an intraoperative examination of the peripheral retina to exclude the occurrence of retinal tears. In our series, there was no evidence of retinal detachment or peripheral retinal breaks at the 6-month follow-up. Approximately 0.5% to 2.0% of all patients having uneventful cataract surgery will have a retinal detachment.8 The risk of retinal detachment does not appear to increase after posterior capsulorhexis; the risk after Nd:YAG capsulotomy is estimated to range from less than 1% to more than 4%.9
In our series, the only complication recorded at 6 months was CME. The incidence of symptomatic CME after uneventful phacoemulsification is not known, but it is less then 2% after extracapsular cataract extraction.10 Cystoid macular edema, confirmed by fluorescein angiography, was present in 2 eyes of the same patient and was accompanied by mild vitritis. This bilateral response to surgery suggests that in retrospect, this patient may have had posterior segment inflammation that contributed to the presence of the vitreous opacities. The CME did not appear until 2 months postoperatively. By this time, the fellow eye had been operated on and had had a similar complication, limiting final BCVA to 6/18 in both eyes at 6 months. We therefore recommend an interval of 3 months before fellow-eye surgery to exclude eyes that may develop this complication.
In conclusion, combining phacoemulsification and anterior vitrectomy can increase the surgical options in the treatment of vitreous floaters with coexisting cataract. We recommend future comparative trials between floaterectomy and combined phacoemulsification/PPV to further evaluate this technique in more patients.
1. Murakami K, Jalkh AE, Avila MP, et al. Vitreous floaters. Ophthalmology 1983; 90:1271-1276
2. Topilow HW, Kenyon KR, Takahashi M, et al. Asteroid hyalosis; biomicroscopy, ultrastructure, and composition. Arch Ophthalmol 1982; 100:964-968
3. Tsai W-F, Chen Y-C, Su C-Y. Treatment of vitreous floaters with neodymium Yag laser. Br J Ophthalmol 1993; 77:485-488
4. Senn P, Schipper S, Perren B. Combined pars plana vitrectomy, phacoemulsification, and intraocular lens implantation in the capsular bag: a comparison to vitrectomy and subsequent cataract surgery as a two-step procedure. Ophthalmic Surg Lasers 1995; 26:420-428
5. Eller AW, Barad RF. Miyake analysis of anterior vitrectomy techniques. J Cataract Refract Surg 1996; 22:213-217
6. Foos RY, Roth AM. Surface structure of the optic nerve head. 2. Vitreopapillary attachments and posterior vitreous detachment. Am J Ophthalmol 1973; 76:662-671
7. Coleman DJ, Lizzi FL, Jack RL. Ultrasonography of the Eye and Orbit. Philadelphia, PA, Lea & Febiger, 1977
8. Coonan P, Fung WE, Webster RG Jr, et al. The incidence of retinal detachment following extracapsular cataract extraction; a ten-year study. Ophthalmology 1985; 92:1096-1101
9. Galand A, van Cauwenberge F, Moosavi J. Posterior capsulorhexis in adult eyes with intact and clear capsules. J Cataract Refract Surg 1996; 22:458-461
10. Wright PL, Wilkinson CP, Balyeat HD, et al. Angiographic cystoid macular edema after posterior chamber lens implantation. Arch Ophthalmol 1988; 106:740-744