New research points to the possibility that lumbar cerebrospinal fluid pressure is lower in patients with normal-angle glaucoma than in patients with higher-pressure glaucoma. The prospective, interventional study, which took place at the Beijing Tongren Hospital in Beijing, included 43 patients with open-angle glaucoma (14 with a normal IOP and 29 with an elevated IOP) and 71 subjects without glaucoma. All patients underwent standardized ophthalmologic and neurologic examinations and measurement of lumbar CSF-P.

Lumbar CSF-P was significantly (p<0.001) lower in the normal-IOP glaucoma group (9.5 ¡À2.2 mmHg) than in the high-IOP glaucoma group (11.7 ¡À2.7 mmHg) or the control group (12.9 ¡À1.9 mmHg). The trans-lamina cribrosa pressure difference (IOP minus CSF-P) was significantly higher in the normal-IOP glaucoma group (6.6 ¡À3.6 mmHg; p<0.001) and the high-IOP glaucoma group (12.5 ¡À4.1 mmHg) than in the control group (1.4 ¡À1.7 mmHg). The extent of glaucomatous visual field loss was negatively correlated with the height of the CSF-P and positively correlated with the trans-lamina cribrosa pressure difference. In the control group, CSF-P was significantly correlated with both systolic blood pressure (p=0.04) and IOP (p<0.001). The trans-lamina cribrosa pressure difference was not significantly associated with blood pressure (p=0.97). In open-angle glaucoma with normal IOP, CSF-P is abnormally low, leading to an abnormally high trans-lamina cribrosa pressure difference. Pathogenetically, a low CSF-P in normal-IOP glaucoma may be similar to a high IOP in high-IOP glaucoma. Consequently, the glaucomatous visual field defect is positively correlated with the trans-lamina cribrosa pressure difference and inversely correlated with the CSF-P. In non-glaucomatous subjects, CSF-P, blood pressure and IOP are significantly associated with each other.

Ophthalmology 2010;117:259-266.

Ren R, Jonas JB, Tian G, et al.


A New Take on Endophthalmitis Prevention and Intravitreal Injections

Recent research suggests that a low rate of endophthalmitis can result from following a protocol that includes use of topical povidone-iodine, a sterile lid speculum and topical anesthetic, but does not require topical antibiotics, sterile gloves or a sterile drape. The Diabetic Retinopathy Clinical Research Network, which conducted the research, administered intravitreal injections of preservative-free triamcinolone acetonide or ranibizumab in two prospective, randomized clinical trials. The standardized procedure for these trials requires using a topical combination product of povidone-iodine, a sterile lid speculum and topical anesthetic, but does not require using topical antibiotics before, on the day of or after injection.

As of February 2009, a total of 3,226 intravitreal injections of ranibizumab and 612 injections of preservative-free triamcinolone had been administered. Topical antibiotics were given on the day of injection in 361 (9.4 percent) of the 3,838 total cases, for several days after injection in 813 cases (21.2 percent), on the day of injection and after injection in 1,388 cases (36.2 percent), and neither on the day of injection nor after injection in 1,276 cases (33.3 percent). Results showed that three cases of culture-positive endophthalmitis occurred after ranibizumab injections (0.09 percent), and no cases occurred after triamcinolone injections. In all three cases of endophthalmitis, topical antibiotics were given for several days after the injection but not before injection.

Arch Ophthalmol 2009;127:1581-3.

Bhavsar AR, Googe JM Jr, Stockdale CR, et al.


SAP Holds Up Against SWAP

Standard automated perimetry is as effective at predicting glaucoma conversion as short-wavelength automated perimetry, according to new research. The prospective, longitudinal follow-up study, conducted by the Rotterdam Eye Hospital in the Netherlands, used a Humphrey Field Analyzer (24-2 program; Carl Zeiss Meditec) to perform SAP and SWAP on 416 subjects with ocular hypertension (intraocular pressure ¡Ý22 and ¡Ü32 mmHg and normal visual fields). Participants were tested every six months for seven to 10 years or until the onset of conversion. Conversion was defined as a reproducible glaucomatous visual field defect in SAP. Outcome was measured by the moment of onset of a reproducible defect in SAP compared with that in SWAP.

While claims have suggested that SWAP can predict conversion to glaucoma three to four years earlier than SAP, the results of this study suggested otherwise. Of the 416 initial participants, 24 eyes of 21 subjects showed conversion in SAP. Of these eyes, 22 did not show earlier conversion in SWAP than in SAP. Standard automated perimetry even showed earlier conversion than SWAP in 15 cases. In only two eyes did SWAP show earlier conversion by up to 18 months.

Ophthalmology 2010;117:30-4.

van der Schoot J, Reus NJ, Colen TP, et al.