2.1.1 Presbyopia is an age-related and progressive loss of focusing power of the lens in the eye. It leads to a gradual decline in the ability to focus on close objects.
2.1.2 Standard treatment for presbyopia is the use of corrective spectacles. As the condition worsens, prescriptions need to be changed accordingly.
2.2.1 Scleral expansion surgery involves making small incisions in the eye and inserting bands to stretch the part of the sclera that lies beneath the ciliary muscles that control accommodation. This procedure is claimed to improve accommodation.
2.3.1 All studies identified were of poor quality. The evidence was limited to one non-randomised controlled study of 29 patients, two very small case series (of six and three patients, respectively) and two case reports. In the controlled study, in which the dominant eye was operated on and the other eye served as a control, improvement in median reading acuity score at 20 cm was reported as –0.41 for operated eyes and –0.35 for control eyes (p < 0.03), indicating that the improvement in operated eyes was greater. No significant difference in reading acuity was found at 30 cm or 40 cm. One case series reported that near visual acuity improved temporarily in 3/8 eyes (38%), but it was no better than before surgery at day 360. In the same study, implanted bands were removed from three eyes upon patient request because of lack of benefit. In another case series of three patients, scleral expansion surgery failed to restore accommodation in any patients. For more details, refer to the Sources of evidence section.
2.3.2 The Specialist Advisors considered the evidence to suggest that the procedure is not efficacious. One Advisor noted that the procedure was controversial because it was based on a novel theory of the mechanism of accommodation of the human eye that was in direct opposition to other generally accepted theories.
2.4.1 The complications reported in the identified studies were: two case reports of band removal because of band migration or chronic pain and swelling; two cases of perforated conjunctiva in a study of 8 patients; and one report of transient elevation of intraocular pressure in a study of 29 patients. For more details, refer to the Sources of evidence section.
2.4.2 The Specialist Advisors listed the main potential adverse events as intraocular haemorrhage, retinal detachment, endophthalmitis, glaucoma, conjunctival scarring and scleral thinning.