The annual incidence of rhegmatogenous retinal detachments is approximately 1 in 10,000 people. The term itself is derived from the Greek word “break” and refers to retinal detachments resulting from a full thickness defect in the retina. General risk factors for rhegmatogenous retinal detachments include myopia, cataract surgery (in particular complicated cases), ocular trauma and retinal detachment in the fellow eye. There are also certain hereditary retinal degenerations including lattice degeneration which also confer a predisposition to retinal detachment. Vitreous traction in all cases result in traction on the retina thus predisposing patients to developing retinal breaks.
Asymptomatic retinal breaks are usually managed conservatively, but progression to clinical retinal detachment been described with the estimate of varying from 11% to 31%. An equivalent percentage of asymptomatic detachment cases achieve spontaneous resolution, so close observation or initial prophylactic treatment with laser or retinal cryopexy may both be considered.
Symptomatic retinal breaks constitute another category of retinal breaks for which intervention is generally indicated. Treatment is performed with laser retinopexy or retinal cryopexy. The risk of a retinal tear at the time of an acute posterior vitreous detachment is only 2% to 4%, but retinal breaks with vitreous traction result in retinal detachment in 50% of patients.
The goal of laser photocoagulation is to generate a firm chorioretinal adhesion surrounding a retinal break to prevent vitreoretinal traction and prevent liquefied vitreous from passing into the subretinal space to cause a retinal detachment. This can delivered at the slit-lamp, using a special contact lens or using an indirect ophthalmoscope (hat) with the patient lying flat.
Extreme cold can be used to seal the retina to the wall of the eye. The goal is to keep fluid from going through the tear and detaching the retina.
This treatment usually takes less than 30 minutes. It is performed with the patient lying on a couch. First the eye is anaesthetised with a local anaesthetic injection (around the eye, not in the eye) and the treatment is applied with a special probe (called a cryopexy probe) that delivers intense cold energy to the retina. This freezes the retina around the tear and creates a scar tissue. The scars seal the retina to the eye wall.
While generally a safe procedure, complications of laser retinopexy may occur. These include inadvertent laser to the macula, choroidal effusions (particularly in cases where large amounts of laser are used), angle closure glaucoma, epiretinal membrane formation, anterior segment laser burns, haemorrhage (of the retina, vitreous, or choroid), choroidal neovascular membrane formation, and the formation of new retinal breaks.
Treatment after laser or retinal cryopexy
No topical (eye drops) are needed after laser, but a 3 weeks course of a topical steroid eye drop (Maxidex 3 times daily) and a 1 week of an antibiotic eye drop (Chloramphenicol 3 times daily) are prescribed after retinal cryopexy.
Follow is necessary 2-3 weeks after treatment. Re-examination and further treatment may be necessary in approximately 10% of all patients. In some cases, prompt surgical intervention may be necessary in case of retinal detachment.
Things to know prior to Laser or retinal cryopexy Treatment:
Please ask a member of staff or your Consultant should you need any additional information before treatment.
Prepared by Mr. H.J. Zambarakji FRCOphth, D.M
Consultant Ophthalmic surgeon