Pars plana vitrectomy (PPV) is a standard surgery for posterior segment diseases, but postoperative cataract progression is the most frequent complication. A large UK registry study reported that the risk of cataract surgery after vitrectomy is about 40%, with 50% requiring surgery at 1 year, 75% at 3 years, and 85% at 5 years.
Cataracts after vitrectomy mainly develop as nuclear sclerotic cataracts. A meta-analysis of 51 studies reported an incidence of 6–100%, varying greatly by underlying disease and follow-up duration.
Combined cataract and vitrectomy surgery (phacovitrectomy) is a procedure that simultaneously performs phacoemulsification and vitrectomy. It offers the advantages of a single surgery and anesthesia, shorter recovery time, and cost efficiency 4). It is indicated for various vitreoretinal diseases such as vitreous hemorrhage, diabetic retinopathy, epiretinal membrane, macular hole, and retinal detachment 4).
Especially in patients aged 60 years or older or in macular hole surgery using long-acting gas, nearly all cases develop visually significant cataracts within one year postoperatively, so combined surgery is widely adopted 5).
The rate of cataract progression after vitrectomy varies by underlying disease and age, but in patients aged 50 years or older, 80% developed cataracts within 2 years after vitrectomy with gas tamponade. At 5 years, about 85% required surgery. In patients under 50, the rate is as low as 7%.
Cataracts that progress after vitrectomy cause the following symptoms.
Cataracts after vitrectomy may present with characteristic findings.
The exact mechanism of cataract progression after vitrectomy is unknown, but the following factors are involved.
Risk factors for cataract progression are as follows:
Prior to cataract surgery in eyes with a history of vitrectomy, the following evaluations are important.
In high myopia, hyperopic shift and prediction errors are common. In a report by Fan et al. of 3 cases of ultra-high myopia (over -30 D), the mean hyperopic shift was 1.41–2.0 D 1).
| Measurement Item | Recommended Method |
|---|---|
| Axial Length | Optical biometry (first choice) |
| IOL Power Calculation | Kane formula has highest accuracy |
Combined surgery tends to cause a myopic shift. However, using the latest IOL formulas (such as the Kane formula) can achieve good refractive outcomes. In silicone oil-filled eyes or high myopia, accuracy decreases further, so careful power calculation is necessary 1).
When cataract and vitreoretinal disease coexist, the following two strategies are available.
Combined Surgery
Phacovitrectomy: Phacoemulsification and vitrectomy are performed in a single surgery.
Advantages: Single surgery and anesthesia. Faster visual recovery. Cost-effective 4).
Indications: Elderly patients. Vitreoretinal disease with significant cataract. Cases where long-acting gas is planned 5).
Staged Surgery
Sequential surgery: Cataract surgery is performed separately before or after vitrectomy.
Advantages: Each surgery can be performed under optimal conditions. Shorter surgical time.
Note: Cataract surgery after vitrectomy carries approximately twice the risk of zonular rupture (1.3% vs 0.6%).
No significant difference in long-term visual prognosis has been reported between combined and staged surgery. However, a systematic review of guidelines reported that combined surgery has a significantly lower incidence of posterior capsule rupture (risk ratio 0.43; 95% CI 0.25–0.73) 5).
Overall, combined surgery is recommended as it offers advantages in early visual recovery, with no significant differences in complication risk or refractive outcomes compared to staged surgery 5).
The indication for combined surgery is determined by the patient’s age, surgical technique, and disease. Generally, it is indicated for elderly patients, but in young patients with sufficient accommodative power, the loss of accommodation after surgery must be considered.
The choice of IOL is also important.
Most cases are performed under topical or local anesthesia. Retrobulbar or sub-Tenon anesthesia may provide posterior pressure and contribute to anterior chamber stability.
It is the standard technique recommended regardless of prior vitrectomy 4). The following surgical parameters are recommended:
This procedure is indicated when phacoemulsification is not possible (e.g., extremely hard nucleus) or in settings with limited medical resources. In eyes with prior vitrectomy, the anterior chamber may be deep, making removal of a hard nucleus difficult.
In eyes with prior vitrectomy, the following intraoperative issues must be addressed.
Generally, good visual prognosis is achieved. About two-thirds of eyes with prior vitrectomy that undergo cataract surgery achieve visual acuity of 0.5 or better. However, due to increased risk of zonular rupture and intraoperative difficulties such as anterior chamber instability, careful surgical planning by an experienced surgeon is important.
The vitreous provides support from behind the lens and contributes to maintaining normal anterior chamber depth. The following are considered main mechanisms of cataract progression after vitrectomy.
Most phakic eyes in contact with silicone oil tamponade develop cataracts.
Gas tamponade (SF6, C3F8) can also cause reversible gas cataract. Posterior capsule opacification is observed from the day after surgery but disappears as the gas decreases.
A systematic myopic shift has been reported in combined surgery. This is thought to be due to changes in postoperative anterior chamber depth or IOL position. According to guidelines for macular hole, there is no significant difference in refractive outcomes between combined and staged surgery 5).
In highly myopic eyes, a hyperopic shift is more problematic. Hyperopic shift is more likely to occur with low-power IOLs, and prediction errors can reach 1–4 D 1).
Surgery using 3D digital visualization systems (DAVS) has gained attention in recent years. Compared to conventional microscopes, it offers advantages such as improved surgeon ergonomics, increased depth of field, and higher magnification.
Rios-Nequis et al. (2021) reported a case of phacovitrectomy using a temporal approach with DAVS in the Trendelenburg position for a patient with severe kyphosis due to ankylosing spondylitis 3). Using a 25G valve system and Constellation platform, the surgery was completed in 40 minutes without complications. Postoperative BCVA at 12 months was 20/40.
This is a new approach that can also be applied to cases where surgery was difficult with conventional positioning.
FLACS uses real-time intraoperative imaging and is expected to improve capsulotomy accuracy and reduce effective ultrasound energy. However, there is insufficient evidence that FLACS is superior to conventional ultrasound techniques in eyes with prior vitrectomy, and cost-effectiveness is unclear. In highly myopic eyes, FLACS may be chosen for zonular protection 1).
In recent years, with advances in small-incision and minimally invasive techniques, toric IOLs and multifocal IOLs have been used in vitreous triple surgery (cataract + vitrectomy + IOL implantation). The wide-viewing system also has less impact on intraoperative fundus observation. However, toric IOLs have issues with postoperative rotation, and multifocal IOLs can make macular observation difficult.
