Scleral buckling appears to decrease ocular rigidity, lowering fluctuations in intraocular pressures (IOP) and, ultimately, reducing the risk for glaucoma progression, according to research published in Ophthalmology Glaucoma. The study shows the reduced ocular rigidity following the procedure decreases IOP variation when moving from sitting to lying down, without inducing any change in aqueous outflow facility.
The researchers reviewed 9 patients with rhegmatogenous retinal detachment (age range, 30 to 72 years) who underwent unilateral 360-degree encircling scleral buckle surgery. Study criteria included no existing glaucoma or unilateral ocular hypertension, and no past vitrectomy in either eye.
Fellow eyes served as comparisons, and median postoperative time was 20 months. Researchers measured IOP with pneumatonometry, outflow facility using 2-minute weighted pneumatonography, and ocular rigidity with Friedenwald equations.
Although IOP in seated position for buckled eyes measured 16.1±2.5 mm Hg, similar to the comparison eyes at 16.7±2.7 mm Hg (P =.50); supine pressure proved lower in eyes with scleral band, 18.7±2.6 mm Hg, compared with nonbuckled eyes, 21.3±2.5 mm Hg (P =.008).
Eyes with scleral band showed a smaller percentage IOP elevation moving from sitting to lying down (P =.005). Buckled eyes also exhibited lower ocular rigidity coefficient compared with fellow eyes (P =.006), but outflow facility was similar (P =.72).
The existing literature offers several theories for reduced ocular rigidity: medical grade silicone material may have more compliance than the scleral wall; or banded eyes become more cylindrical, shifting greater stress toward the equator; or the effect of a mechanical system that decreases higher pressure from increased volume might lessen rigidity.
“While causality cannot be determined from this cross-sectional study, the reduction of ocular rigidity and IOP change with body position may reduce IOP fluctuations and contribute to the lower rate of glaucoma in scleral buckle patients compared with those who have vitrectomy alone or vitrectomy with scleral buckle,” the researchers report.
Limitations of the investigation included a small sample of nondiverse, White individuals, along with slight variations in surgical choices, implant type, and lack of data for degree of buckle imbrication. This study is first to examine lower ocular rigidity after buckle surgery in living patients.
Lyons LJ, Kazemi A, Bakri S, et al. The effect of scleral buckle surgery on tonographic outflow facility, positional intraocular pressure and ocular biomechanics. Ophthalmol Glaucoma. Published online July 21, 2023. doi:10.1016/j.ogla.2023.07.007