Assessment of optic disc photographs for glaucoma by UK optometrists: the Moorfields Optic Disc Assessment Study (MODAS)

The authors studied intraobserver and interobserver agreement, under monoscopic and stereoscopic conditions, in estimating vertical cup-to-disc ratios and in assessing whether a disc had glaucomatous damage. Six glaucoma experts evaluated 75 optic disc photographs under both viewing conditions. The experts also re-evaluated 25 photographs. Intraobserver agreement in estimating vertical cup-to disc ratios was high (median weighted kappa, 0.79). Interobserver agreement in estimating vertical cup-to-disc ratios was moderate (stereoscopic median weighted kappa, 0.67); individual experts differed by as much as 0.2 disc diameters (DD) monoscopically and 0.16 DD stereoscopically. The observers estimated larger vertical cup-to-disc ratios when evaluating the same discs under stereoscopic conditions than under monoscopic conditions. Intraobserver agreement in assessing glaucomatous disc damage was substantial (median kappa, 0.76). Interobserver agreement in assessing glaucomatous damage was moderate (stereoscopic median kappa, 0.50). This study confirms the ability of experts to reliably evaluate the optic disc within themselves and emphasizes the need for developing standardized methods for interobserver evaluation of the optic disc in glaucoma.

To describe the design, activity, and quality of the referral refinement phase of a novel glaucoma shared-care scheme. Eight Optometrists with a Specialist Interest in glaucoma (OSI) were trained to perform a community-based comprehensive glaucoma evaluation of low-risk glaucoma hospital referrals (only one/none of the following factors noted for either eye: abnormal optic disc, abnormal visual field, abnormal intraocular pressure (IOP; 22-28 mmHg or IOP asymmetry)) using equipment standardized to that of the hospital glaucoma service. One hundred and thirty-eight (27%) of a total of 512 glaucoma-related referrals were deemed 'low risk'. Their choice of OSI discharged 40 (35%). The consultant agreed (virtually) with the decision to discharge with 28 (70%) and disagreed with 12 (30%). Comparing findings between OSI and consultant for 99 referred patients, sensitivity, specificity, and negative predictive values for a suspicious optic disc were 78, 61, and 79%, respectively. For an IOP of >21 mmHg, they were 74, 85, and 90%, respectively. For an occludable anterior chamber angle (Van Herick's versus gonioscopy), they were 69, 88, and 94%, respectively. This referral refinement process can reduce numbers of false-positive referrals attending the hospital glaucoma service while retaining a relatively high level of examination quality.

To determine the agreement among optometrists, ophthalmologists, and ophthalmology residents in assessing glaucomatous optic nerve damage. The authors also determined the sensitivity of each group of observers for identifying glaucomatous optic nerve damage.