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Br J Ophthalmol: first published as 10.1136/bjo.60.11.778 on 1 November 1976. Downloaded from

Brit. Y. Ophthal. (1976) 6o, 778

The in i: Classification

R. A. HITCHINGS Moorfields Hospital, City Road, London AND G. L. SPAETH Wills Eye Hospital, Spring Garden Street, Philadelphia I9I30, USA

The pale, cupped disc found in the final stages of deepening of the cup exposing the lamina cribrosa glaucomatous disease has been known from the (the 'laminar dots' sign (Reed and Spaeth, 1974)); time of Von Graefe (I854). Since then many and change in the course of the retinal vessel which observers have described changes that occur at the is seen as a sharp change in direction ('kinking' or optic disc in chronic, simple glaucoma. There has bayoneting (Reed and Spaeth, 1974)). In addition, been particular interest in changes which may the presence of localized regions of nerve fibre loss occur in the early stages of the disease. or 'gutters' has been demonstrated in some cases Studies of the normal population have shown of early glaucoma by Hoyt, Frisen, and Neuman that while there is a wide diversity in the appearance (1973). copyright. of the normal optic disc, in a single subject (Armaly, The aim of this paper was to assess systematically I969; Fishman, I970; Kolker and Hetherington, glaucomatous discs and look for those features that 1970; Portnoy, 1973) the two discs are remarkably are commonly associated. As a result, five different similar (Witsiuk, I966; Kronfeld, 1970; Woodruff, types of optic disc appearance are described. 1970; Portnoy, I973). In contrast, individuals with In this paper the term glaucoma has been used glaucomatous disease usually show manifest asym- for all cases in which the intraocular pressure metry of the two optic discs (Fishman, I970; exceeded 22 mmHg and glaucomatous cupping

Kolker and Hetherington, 1970). was visible on stereoscopic examination of the disc. http://bjo.bmj.com/ Many criteria have been used to describe the This has meant including cases in which the optic glaucomatous optic disc. Important among these is disc appeared normal by uniocular , the ratio of the cup diameter to the diameter of the and even cases in which glaucomatous cupping was entire disc (Pickard, I923; Snydacker, I964; visible without detectable field loss. Hollows and McGuiness, I967; Armaly, i967, I968; Schwartz, I973; Tomlinson and Phillips, I974). was Material and methods This initially measured horizontally, but on September 29, 2021 by guest. Protected recently measurement of the vertical cup to disc This study was based on analysis of stereoscopic disc (C/D) ratio has been stressed, after recognition that photographs of 252 patients from the files of the changes in the tend initially to affect the Glaucoma Clinic at Wills Eye Hospital. The patients vertical diameter (Chandler and Grant, I965; were mostly cases of known or suspect glaucoma Kronfeld, I967; Kirsch and Anderson, 1973; attending the Glaucoma Service. In addition, 25 normal Weisman, Assif, Phelps, Podos, and Becker, 1973). patients on the files of the Glaucoma Service were Stereoscopic examination of the optic disc in early included. The diagnosis was unknown at the time of glaucoma reveals signs which help to distinguish analysis of the stereophotographs. the normal from the Most photographs were taken within an I8-month glaucomatous cup (Anderson, period using a Zeiss flash II camera with a X 2-0 I975; Reed and Spaeth, I974). These signs are adaptor. Stereoscopic photographs were obtained after evidence for acquired tissue loss and account for maximal pupillary dilatation by photographing the clear the asymmetry previously noted. Tissue loss may optic disc images obtained at each end of a horizontal appear in a variety of forms: thinning of the neuro- traverse of the camera body. This traverse was usually retinal rim, either localized or generalized; depres- 3 to 4 mm. sion or steepening of the walls of the cup (the Slides were examined with a stereoscopic viewer. tinted hollow (Reed and Spaeth, 1974) or saucer); The stereo pairs of the two were directly compared. Special note was made of identifying characteristics Address for reprints: R. A. Hitchings, FRCS, Moorfields Eye suggestive of tissue loss. Hospital, City Road, London ECIV 2PD The following criteria were analysed: Br J Ophthalmol: first published as 10.1136/bjo.60.11.778 on 1 November 1976. Downloaded from The optic disc in glaucoma 779

THE VERTICAL CUP/DISC (C/D) RATIO retinal vessel as it passed over the surface of the optic The 'cup' was defined in terms of configuration; its disc and a sharp 'kinking' or change in the vessel's extent was determined by drawing a hypothetical line direction either in the same plane as the disc surface or vertically on the anterior surface of the disc from the at an angle to it. The gradual curve was considered most superior to the most inferior aspect of the disc normal; the kink was thought to be an acquired change margin; the segment of the line not in contact with the that occurred secondary to enlargement of the optic cup. disc surface was considered to be 'the cup'. The ratio Kinking resulted in nasal displacement of the vessels, (expressed in tenths) of that segment to the length of and was of most significance when it occurred at the the entire line was the 'cup/disc ratio' (C/D). Pallor of outer margin of the disc. the optic disc played no part in the assessment of the C/D ratio (Schwartz, 1973). PIGMENT CLUMPING The presence or absence of pigment clumping around THE WALLS OF THE OPTIC CUP the margin of the optic disc was noted. The specific points checked were: degree of inclination in the walls, variation in the slope of the walls of any one cup, and difference between cups of the two eyes NERVE FIBRE LAYER in each patient. The presence of a more steeply-sided The nature of the nerve fibre layer was observed as far cup despite identical C/D ratios was considered sus- as possible within the limits of the examination tech- picious of enlargement of the cup. nique. Where refractile lines taking the known pattern of the nerve fibre layer (NFL) were visible the NFL was THE DEPTH OF THE OPTIC CUP thought to be present. If none of the gutters or grooves described by Hoyt and others (1973) was visible the The depth of the optic cup was described as 'normal', NFL was called 'intact'. If such a gutter was observed 'deep', or 'bean-pot'. 'Normal' depth referred to an it was listed as a nerve fibre bundle defect (NFBD). If optic cup which did not show evidence of actual posterior no NFL could be seen at all it was called 'invisible'. bowing of the lamina cribrosa itself; the cup, however, copyright. could extend as far posteriorly as the 'laminar dots' (taken to represent the lamina cribrosa) described by Results Reed and Spaeth (I974). In a 'deep' cup the lamina cribrosa appeared posteriorly bowed. A 'bean-pot' cup, Stereoscopic photographs from 504 eyes of 252 so called because of its likeness to a spherical clay pot, patients were analysed. The optic discs were was diagnosed when posterior displacement of the divided into two groups, normal and pathological, lamina cribrosa coexisted with undermining of the this second being subdivided into five types of neuroretinal rim; in transverse section the walls and glaucomatous cupping (overpass, cupping without base of the cup formed the major part of a circle. There pallor of the neuroretinal rim, cupping with pallor http://bjo.bmj.com/ was usually little difficulty distinguishing between a of the neuroretinal rim, focal notching of the flat or a posteriorly-bowed lamina cribrosa. Similarly, neuroretinal rim, and although there was clearly a spectrum of changes, bean-pot cupping), whose differentiation between the 'deep' and the 'bean-pot' characteristics will be described. The overall cup was usually fairly straightforward. In those few numbers and characterizing features are seen in cases where differentiation between two descriptive the Table. Stereophotographs illustrating each of types was not easy, the shallower type of cup depth was these examples may be seen in Figs 1-5. chosen. on September 29, 2021 by guest. Protected CHARACTERISTICS OF DISC SUBTYPES THE NEURORETINAL RIM Normal disc The pallor and the width of the neuroretinal rims were graded. The colour achieved with transparencies was A disc was considered 'normal' in appearance if not an exact match with the colours seen on stereoscopic the neuroretinal rim was pinkish and of equal examination, and pallor of the rim could not always be thickness throughout, or with its thinnest portion differentiated from the normal pinkish colour. As a at the temporal margin on the horizontal meridian result, comments on colour were to restricted recording of the disc. There were no sharp whether the neuroretinal rim was pale or pink. Thinning deviations of any of the neuroretinal rim was far more easily quantitated, retinal vessel where it traversed the disc surface. and ranged from being just noticeable to a complete This type of disc usually had a C/D ratio of less absence of rim tissue with extension of the cup to the than o 5, an optic cup of 'normal' depth (as defined outer disc margin. The size of the arc involved in above), and a visibly intact nerve fibre layer. When thinning ranged from a localized segment (producing a the two optic discs from any patient were highly 'notch') to circumferential thinning of the entire symmetrical, they were considered 'normal'; this neuroretinal rim. latter definition allowed optic discs with a C/D ratio greater than o 5, a sharply deviating retinal DISPLACEMENT OF THE RETINAL VESSELS vessel, or a poorly visualized nerve fibre layer to be Distinction was made between a gradual curve of a included in this normal group. The optic discs of Br J Ophthalmol: first published as 10.1136/bjo.60.11.778 on 1 November 1976. Downloaded from

780 British Yournal of Ophthalnmology

Table Clinical features of glaucomatous discs Vertical CID Cup depth Vessel -______- Incidence Rim displace- Pigment Nerve fibre bundle Tvpe No. Percentage Range Mean Normal Deep Bean- of Notch pallor ment clumping defect of total pot overpass (No.) (No.) (Bayon- (No.) No.) eting) (No.) (Per cent) (No.) (I 6 - 27 0 0 6 27 I) 222 Intact I. Normal 231 46 o-o-6 0-3 223 g Invisible

2 44 3 3 1 3 21 (65) 24 Intact 2. Overpass vessels 44 9 0-2-0-9 o-6 42 17 Invisible 3 NFBD without 3. Cupping 82 Intact of rim 124 25 0-3-0-9 0-7 44 76 4 12 0 0 I22 74 (6I) pallor 30 Invisible I2 NFBD 4 Cupping with 68 68 (82) 6o Invisible pallor of rim 68 12 0-7-0-9 o-85 II 57 - I0 20 58 8 NFBD

I Intact 5. Focal notching 23 5 04-03 0-7 23 25 21 21 21 (91) 3 lnvis'ble I9 NFBD I - 0 14 (92) 3 lnvisible 6. Bean-pot 14 3 0-9 -9 - 14 0 13 13 I Intact copyright. http://bjo.bmj.com/ on September 29, 2021 by guest. Protected

FIG. I Overpass cupping; retinal vessels (dark arrows) pursuing a relatively undeviated course over the optic cup (hollow arrows) For satisfactory viewing these stereo pairs should be examined using a suitable convex sphere. With higher powers of sphere, fusion may be obtained by decentring the spheres. To do this, increase the distance between them

all 25 patients. clinically considered normal fell into gross enlargement of the optic cup, the phrase this category. 'overpass cupping' was used. This type of intra- papillary tissue loss occurred to a minor degree in some discs classed as 'normal'. More frequently, it and Overpass cupping (Kronfeld, i967; Spaeth involved the disc extensively, and the two discs Hitchings, I975) asymmetrically, being the major anatomic abnor- Where tissue loss within the papilla mality visible on stereoscopic examination. In these was visible on stereoscopic examination, but without cases the retinal vessels could be seen pursuing a Br J Ophthalmol: first published as 10.1136/bjo.60.11.778 on 1 November 1976. Downloaded from The optic disc in glaucoma 78I

FIG. 2 Cupping without pallor of the neuroretinal rim; glaucomatous cupping is suggested by localized (inferior) thinning of neuroretinal rim, steeply-sided walls to cup, an angulated course followed by infero-temporal vein around rim of cup, and, in this case, a splinter haemorrhage (arrow) copyright. http://bjo.bmj.com/ on September 29, 2021 by guest. Protected

FIG. 3 Cupping with pallor of the neuroretinal rim; glaucomatous cupping associated with pallor of all or part of neuroretinal rim. In this example neuroretinal rim (black arrows) has to be differentiated from adjacent peripapillary atrophy. Pallor of neuroretinal rim may be seen in one segment (hollow arrows)

relatively undeviated course across the disc surface, displacement of retinal vessels. The true size of apparently unsupported by disc tissue (this the optic cup was only apparent on stereoscopic characteristic of retinal vessels 'bridging' an optic examination. This type of tissue loss (overpass cup resembles the 'flyovers', or overpasses at road cupping) was considered as a separate class. junctions, hence the name). On direct ophthalmo- scopic examination, the optic cup with overpass cupping did not appear particularly enlarged as a Cupping without pallor of the nenroretinal rim major uniocular clue to the size of the optic cup is An optic disc with a pinkish neuroretinal rim but Br J Ophthalmol: first published as 10.1136/bjo.60.11.778 on 1 November 1976. Downloaded from 782 British yournal of Ophthalmology

FIG. 4 Focal notching of the neuroretinal rim; neuroretinal rim is very thin in one localized segment. This is associated with localized enlargement of optic cup (arrowed). There is no evidence elsewhere on optic disc of enlargement of optic cup copyright. http://bjo.bmj.com/ on September 29, 2021 by guest. Protected

FIG. 5 Bean-pot cupping; enormous size of optic cup, together with posterior bowing of laminar cribrosa and undermining of the neuroretinal rim resembles a 'bean pot' or gourd. Undermining of neuroretinal rim is emphasized by the retinal vessels 'disappearing' behind the rim for part of their course (arrows)

with apparent enlargement of the optic cup was some cases considered distinctive enough to considered to have cupping without pallor of the indicate acquired glaucomatous cupping. In other neuroretinal rim. The pertinent clues were marked cases the changes were less marked, evidence for thinning of the neuroretinal rim together with glaucomatous cupping being obtained by compari- steeply-sided walls to the optic cup and sharply son of the two optic discs from one subject. Here angulated vessels, resulting in an oval cup out of the following were taken as evidence for enlarge- proportion to that expected from the shape of the ment: asymmetry of the surface area of the cup (a optic disc (Portnoy, 1973). This appearance was in difference of 0>o2 in the C/D ratio was considered Br J Ophthalmol: first published as 10.1136/bjo.60.11.778 on 1 November 1976. Downloaded from

The optic disc in glau0coma 783

significant); the steepness of the slope of the walls (GLS). Furthermore, only those patients with of the cup, or the depth of the cup. These signs, technically excellent photographs were chosen for taken to indicate an acquired change, were most analysis. frequently noted at the infero-temporal part of the There appear to be distinct morphological disc cup. The supero-temporal area was the next most types occurring in glaucomatous disease. Although frequently affected, while enlargement in other clearly there was a definite overlap between groups, directions occurred less often. and some features were found common to more Many of these optic discs could have been than one type it was still possible to classify the discs considered normal if examined individually without into five distinct morphological types. It was the evaluation of the fellow disc. It was only by predominant feature (overpass, bean-pot, etc.) comparing the two discs that asymmetry became which decided placement. Different optic disc types apparent. could have similar degrees of visual field loss and therefore be at the same stage of glaucomatous Cupping with pallor of the neuroretinal rim disease from the functional point of view (Hitchings and Spaeth, in preparation). In certain optic discs, cupping was combined It is always slightly suspect to state that an with pallor of the neuroretinal rim-that is reduced individual optic cup has enlarged without docu- vascularity of the neuroretinal rim which affected mentation in a longitudinal study. The inference part or all of its extent. Also present were those that such enlargement does occur is based on signs described that suggested enlargement of the previous studies which reveal striking symmetry optic cup and thinning of the neuroretinal rim between the two discs in any one person (Fishman, secondary to raised intraocular pressure. The nerve I970; Portnoy, I973). there is fibre bundle layer was usually invisible. Furthermore,

evidence that the normal cup is horizontally oval copyright. or circular (Kirsch and Anderson, I973; Weisman Focal notching of the neuroretinal rim and others, I973). Vertical ovality of the cup which In some eyes localized enlargement of the optic exceeds that which could be explained on the basis cup with thinning of the neuroretinal rim was of the vertical ovality of the disc itself suggests an present (notching), but without apparent cup acquired change (Kirsch and Anderson, I973; enlargement elsewhere. This appearance was Portnoy, 1973; Weisman and others, 1973). sufficiently distinctive to justify a separate category. An alternative explanation for an acquired In this series, the notch was usually in the infero- enlargement of the optic cup is that it is age temporal quadrant. These eyes had the highest related. It seems likely that the optic cup may http://bjo.bmj.com/ incidence of visible nerve fibre bundle defects. enlarge with age. Pickard (I948) noted this from a longitudinal study, while Schwartz, Reuling, and Garrison (I975) demonstrated an increase in the Bean-pot cupping horizontal C/D ratio with age by examining Bean-pot cupping referred to the extreme enlarge- stereophotographs of the optic disc. This is at ment of the optic cup already described. This variance with the earlier work of Armaly (i967) who occurred with or without pallor of the neuroretinal felt, on the basis of uniocular ophthalmoscopy, that on September 29, 2021 by guest. Protected rim. the optic cup did not increase with age. Although There was a general tendency for the two optic Schwartz and others (I975) did not specifically discs of any one patient to exhibit the same optic measure it, it seems possible that the vertical C/D disc type. This was especially true for those cases ratio does not enlarge more than the horizontal with localized, or focal, notching and those with C/D ratio. 'bean-pot' cupping. When the same optic disc The existence and extent of peripapillary pigment types were not found, the following combinations clumping was noted (Primrose, I 972), but the occurred: normal + cupping with or without Present study shows that it is not pathognomic for neuroretinal rim pallor; overpass + cupping with glaucoma as it was found in 27 cases (i I per cent) or without neuroretinal rim pallor. of normal discs and in nine of these it occurred in eyes that were considered clinically normal. Discussion However, in agreement with the finding of Wilensky and Kolker (I976) the incidence of pigmentary The proportional representation of each type in clumping rose considerably with glaucomatous this series does not necessarily reflect the overall disease, occurring in over 90 per cent of eyes with incidence in a glaucoma population. In the first notching of the optic cup and bean-pot cupping. place the population was highly selected because In addition, in cases with bilateral glaucomatous of the referral nature of the practice of one of us disease, the eye with the more advanced changes Br J Ophthalmol: first published as 10.1136/bjo.60.11.778 on 1 November 1976. Downloaded from

784 British Jouirnal of Ophthalmology

tended to show a greater amount of pigmentary vascular and haematological disease. These factors clumping. may act singly or in varying combinations. This is In those cases where it was possible to re-examine borne out to some extent by our knowledge of the the patients with red-free light (Hoyt and others, natural course of glaucomatous disease. Children I973), we found that examination of stereophoto- and young adults are known to develop glauco- graphs for defects with nerve fibre layer appeared matous cupping and visual field loss after a to be just as accurate. Care was taken to differentiate comparatively short time. The flame-shaped true from pseudo 'gutters'. All cases in this series haemorrhage may indicate sudden visual field loss with nerve fibre bundle defects had glaucomatous (Drance and Begg, 1970). Conversely some nerves cupping. The nerve fibre layer could not be appear capable of withstanding many years of visualized at all in many patients with glaucoma, increased intraocular pressure without damage. notwithstanding the presence of normal fields (on The appearance of the glaucomatous disc may be kinetic Goldmann field testing). Visibility was not affected by many factors. Recognition of differing improved with red-free light. There would appear morphological types may be a step towards recog- to be a non-specific depression of light reflexes nizing the predominating factors in each case. arising from this layer which is associated with, and possibly related to, raised intraocular pressure, and/ or age. Summary The highest incidence of nerve fibre bundle Five different descriptive types of glaucomatous defects was seen in cases with localized notching of optic discs are described, based on the examination the neuroretinal rim. There was always a corres- of X 2 magnification stereophotographs of 252 ponding 'dense' field defect on Goldmann perimetry, patients from the files of the Glaucoma Service at in marked distinction from discs in other groups Wills Eye Hospital. The method of analysis is copyright. where it could be difficult to state whether a field described in detail. These types include: overpass defect was present at all. In the group of eyes with cupping, cupping without pallor of the neuroretinal cupping without neuroretinal rim pallor, it was rim, cupping with pallor of the neuroretinal rim, possible to detect changes in the appearance of the focal notching of the neuroretinal rim, and bean-pot optic nerve that suggested glaucoma, before nerve cupping. fibre bundle defects could be seen. It appeared These morphological types may be caused by that visualization of the nerve fibre layer was a variations in factors contributing to the pathogenesis valuable guide when present. That it could not be of glaucomatous eyes. Recognition of these differing seen in many cases, despite full fields, suggests its types may help in determining the factors in each http://bjo.bmj.com/ value in diagnosis is limited. case. The variable appearance of the optic nerve in glaucoma suggests a different response of the nerve We thank Mr R. J. Smith, and Professor J. Gloster for to differing disease processes. This may reflect their advice. anatomical differences between optic nerves, varia- The investigation was supported by National Institute tion in the duration of the height of the raised of Health Research Grant No. EYoo67704 from the

intraocular pressure and coexistence of cardio- National Eye Institute. on September 29, 2021 by guest. Protected

References ANDERSON, D. R. (1975) 'Transactions of the New Orleans Academy of Ophthalmology: Symposium on Glaucoma', chap. 7 Clinical evaluation of the glaucomatous fundus, p. 95. Mosby, St Louis ARMALY, M. F. (i967) Arch. Ophthal., 78, 35 (i968) Amer. J. Ophthal., 68, 40I (i969) Trans. Amer. Acad. Ophthal. Otolaryng., 73, 898 CHANDLER, P. A., and GRANT, W. M. (i965) 'Lectures on Glaucoma', chap. i. Kimpton, London DRANCE, S. M., and BEGG, I. S. (I970) Canad. J. Ophthal., 5, 137 FISHMAN, R. S. (I97o) Arch. Ophthal., 84, 590 HITCHINGS, R. A., and SPAETH, G. L. (I977) The optic disc in glaucoma: 2. Disc-field correlation (in preparation) HOLLOWS, F. E., and MCGUINESS, R. (I967) Trans. ophthal. Soc. Aust., 25; Trans. ophthal. soc. N.Z., 19, 33 (Combined vol., Trans. 2nd Conjoint Meeting Ophthal. Socs. of Aust. and N.Z., i966) HOYT, W. F., FRISEN, L., and NEUMAN, N. (I973) Invest. Ophthal., 12, 8I4 KIRSCH, R. F., and ANDERSON, D. R. (1973) Amer. J3. Ophthal., 75, 442 KOLKER, A. E., and HETHERINGTON, J. (I970) 'The Diagnosis and Therapy of the ', 3rd ed., chap. 9, Optic discs, p. 143. Mosby, St Louis KRONFELD, P. C. (I967) 'Symposium on Glaucoma', chap. 3, The optic nerve, p. 62. Mosby, St Louis (1970) 7. Amer. optom. Assoc., 23, I56 Br J Ophthalmol: first published as 10.1136/bjo.60.11.778 on 1 November 1976. Downloaded from The optic disc in glaucoma 785

PICKARD, R. (1923) Brit. Jt. Ophthal., 7, 8i (1948) Ibid., 32, 355 PORTNOY, G. L. (I973) Amer. Jt. Ophthal., 76, 655 PRIMROSE, J. (1972) Clinical evaluation of glaucomatous discs, in J. S. Cant, 'The Optic Nerve' (Proc. 2nd William MacKenzie Memorial Symposium, I97I). Kimpton, London REED, R. M., and SPAETH, G. L. (I 974) Trans. Amer. Acad. Ophthal. Otolaryng., 78, 225 SCHWARTZ, B. (I973) Arch. Ophthal., 89, 272 SCHWARTZ, J. T., REULING, F. H., and GARRISON, R. J. (1975) Brit. Y'. Ophthal., 59, 2I6 SNYDACKER, D. (I964) Amer. 5'. Ophthal., 58, 958 SPAETH, G. L., and HITCHINGS, R. A. (1975) Overpass: Is this an early sign of glaucoma? Read at the Trans. Amer. Acad. Ophthal. Otolaryng., Dallas TOMLINSON, A., and PHILLIPS, C. I. (1974) Brit. Y. Ophthal., 58, 543 VON GRAEFE, A. (I854) V. Graefes Arch. Ophthal., I, 37I WEISMAN, R. L., ASSIF, C. P., PHELPS, C. D., PODOS, S. M., and BECKER, B. (1973) Trans. Amer. Acad. Ophthal. Otolaryng., 77, I57 WILENSKY, J. T., and KOLKER, A. E. (1976) Amer. Y'. Ophthal., 8i, 34I WITSIUK, W. (I966) Ophthalmologica (Basel), 152, 57 WOODRUFF, M. E. (1970) Amer. 5'. Optom., 47, 315 copyright. http://bjo.bmj.com/ on September 29, 2021 by guest. Protected