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Home , Endophthalmitis, Epikeratophakia, Keratoconus

(1990) 4, 531-534

Epikeratophakia for

BREIT L. HALLIDAY London

Summary Results of the author's first 15 cases of for keratoconus are pre­ sented. All were intolerant of contact correction and could not achieve satisfactory acuity with spectacle correction due to corneal ectasia and irregular . The average follow-up was 13 months. Seventy-three per cent of treated had a pre-operative spectacle acuity of 6/60 or worse. One eye had a pre­ existing that limited final acuity, but every other eye achieved a post­ operative spectacle acuity of 6/12 or better and 50% achieved 6/6. One eye had 11 of post-operative astigmatism and required penetrating keratoplasty; the remaining eyes had an average 'astigmatism of 1.9 dioptres. Epikeratophakia appears to be a safe alternative to penetrating keratoplasty in selected cases.

Although most cases of keratoconus can be slow post-operative recovery of successfully managed with spectacle or con­ and a slightly sub-optimal final visual acuity tact lens correction, a small proportion of due to the fact that the host remains in patients require to improve visual situ. acuity.! This paper presents the results from the first Penetrating keratoplasty is the most com­ 15 cases of epikeratophakia for keratoconus mon surgical procedure and ustially results in performed by the author. a clear and good visual acuity.2,3 Impor­

tant common complications of penetrating Patients and Methods keratoplasty include allograft rejection and selection high residual astigmatism. More rarely, seri­ Patients were referred to the Corneal Clinic at ous complications such as primary graft fail­ Moorfields Eye Hospital where they were ure, and may assessed as potential candidates for surgery. occur. Epikeratophakia was only considered when Epikeratophakia is an alternative tech­ simpler alternatives were considered inappro­ nique that can be used in selected cases of ker­ priate. In every case spectacle correction was atoconus.4-7 The aim of surgery is to flatten impossible due to irregular astigmatism and the ectatic cornea and to eliminate irregular astigmatism. Compared to penetrating ker­ all patients were intolerant of hard contact atoplasty, epikeratophakia is less invasive, lenses. Every eye treated had marked corneal being essentially extraocular, and may there­ ectasia, but in no case was there any great fore be safer. Epikeratophakia has additional degree of central corneal scarring. potential advantages; rejection of the cryo­ lathed lenses does not occur and, as the host Lens manufacture cornea remains intact, astigmatism may be Lenses were manufactured by the author less of a post-operative problem. Potential using donor supplied from Moorfields disadvantages of epikeratophakia include Eye Hospital . Only corneas that

Correspondence to: B. L. Halliday FRCS, Moorfields Eye Hospital, City Road, London EC1V 2PD. 532 BREIT. L. HALLIDAY had been stored either in K-Sol or in pocket into the peripheral cornea from the McCarey-Kaufman storage media were used. base of the trephine cut. In general these corneas had been rejected as To minimise the possibility of residual epi­ suitable for penetrating keratoplasty by virtue thelial cells causing interface opacities, a cel­ of the age of donor, poor endothelial appear­ lulose swab, barely moistened with absolute ance or prolonged time in storage. A 9 mm alcohol, was then used to wipe the cornea disposable trephine was used to punch out, within the area of the trephine cut. The cor­ from the endothelial side, a corneal disc from nea was then washed thoroughly with a the donor cornea. stream of irrigating fluid. A specially developed cryolathe (City­ The epikeratophakia lens was then sutured crown Sales, 14 Kempston Close, Gatehouse in place with interrupted 9/0 nylon. Full tl1ick­ Way, Aylesbury, Buckinghamshire) was used ness bites were taken through the wing of the to manufacture the lenses. The lathe has a lens and the needle was then passed into the concave, 8 mm radius, aluminium base for the depth of pocket at the base of the trephina­ corneal disc which is cooled using carbon tion. The suture was tied very tightly to flatten dioxide to approximately -4 0° Celsius. At the ectatic cornea. For mild to moderate this temperature the cornea is frozen hard and amounts of keratoconus this suture tightening lathing becomes possible. The 9 mm corneal alone was sufficientto flattenthe cornea. For disc was mounted on the lathe, frozen, and more marked keratoconus an assistant helped then machined with a diamond tipped cutting to flatten the cornea as the suture was tied by tool from the endothelial side. An 8 mm pressing on the cornea with a disposable irri­ radius of cut was used to give a parallel sided gating vectis (Steriseal 161925G). In every lens of thickness 0.5 mm. A 'wing' of thick­ case sufficient flattening of the cornea was ness 0.3 mm was then lathed on the peripheral achieved without the need to perform a part of the corneal disc to facilitate tucking of paracentesis. the lens into the corresponding pocket in the After the firsteight sutures were in place, a host cornea. cyclodialysis spatula was used to tuck the wing of the lens into the peripheral pocket. The Surgical Technique resulting corneal contour was then subjec­ An almost identical technique was used on all tively assessed using an operative kerato­ the patients. Surgery was performed under scope. Additional sutures were then added or general anaesthesia. Superior and inferior over-tight sutures removed, as required, in an rectus sutures were used only if the eye was attempt to minimise any suture induced not pointing vertically. astigmatism. Corneal was removed using a The procedure was completed with a sub­ D15 scalpel blade. A caliper, set to 7.5 mm, conjunctival injection of antibiotic and the eye was used to guide the area of epithelial remo­ was padded until the first dressing. val; peripheral corneal epithelium was left Patients were generally discharged on the intact to facilitate subsequent post-operative first post-operative day using chloramphen­ epithelial regeneration over the sutured epi­ icol 0.5% and prednisolone 0.3% eye drops keratophakia lens. Care was taken to ensure three times a day. Eyes were left unpadded that the scalpel blade did not pause as it swept and bandage contact lenses were not used. across the cornea as this can result in linear Sutures were left in place unless they become marks on Bowman's layer. loose or they appeared to be contributing to A 7 or 7.5 mm Hessburg-Baron suction high or irregular astigmatism. trephine was then used to make a circular cut in the host cornea to a depth of approximately Results 190 microns (turning the capstan by three One eye was treated in each of 15 patients one-quarter turns). whose average age was 25 years (range 16 to A 23 gauge hypodermic needle, mounted 42). Pre-operative spectacle acuities were with its tip bent to an angle of 90°, 1.5 mm generally very poor with 11 eyes (73%) having from the end, was then used to dissect a an acuity of 6/60 or worse. Further details are EPIKERATOPHAKIA FOR KERATOCONUS 533 given in Table I. The average length of fol­ the patient with just 0.5 dioptres of astigma­ low-up was 12.8 months. tism. Patient number three had two dioptres The majority of patients had an uneventful of astigmatism at three months after surgery post-operative course with rapid re-epithelial­ and all the sutures were removed. The astig­ isation of the epikeratophakia lens and with matism increased to five dioptres by five steadily improving lens clarity paralleled by months and to 11 dioptres by seven months. an improvement in corrected visual acuity. At this stage the lens was removed and sub­ The topical steroid and antibiotic drops were sequently penetrating keratoplasty was gradually tailed off and in no case were they performed. continued beyond six weeks. Table I shows the final and There were few complications in the post­ visual acuities. For patient number three the operative period. In three cases it was necess­ figures given are for the obtained ary to temporarily increase the dose of topical just before the epikeratophakia lens was steroids (up to six times a day) to control post­ removed. Patient eight was assumed to be operative . amblyopic; she had surgery at the At most clinic visits a Placido disc was used age of 18 months and had no recollection of to verify the corneal regularity and where good acuity in the operated eye. Unfortu­ possible this was checked with refraction. nately these facts were not appreciated prior Individual sutures were removed if they to epikeratophakia surgery. Of the remaining become loose, or if it was felt, on the basis of 14 patients, all achieved a post-operative the Placido reflex or the refraction, that they spectacle acuity of at least 6112, with 11 (78%) were contributing to a high astigmatism. It reaching 6/9 and seven (50%) managing 6/6. was not always possible to predict the effect of Excluding patient number three, the average individual suture removal. For example in astigmatism was 1. 9 dioptres. one case (patient number 11) an astigmatism Recovery of visual acuity after epikera­ of three dioptres was initially recorded. A tophakia is believed to be slow. The average suture was removed in an attempt to reduce time to achieve 6/12 acuity was 3.6 months this. The result was that the unopposed action and for the patients that reached 6/6 acuity, of the remaining sutures induced astigmatism, this was achieved by an average of 5.1 in the axis orthogonal to the initial astigma­ months. Survival (Kaplan-Meir type) analysis tism, of 24 dioptres. To correct this the mis­ gives a graphical description of the recovery sing suture was first replaced, then individual of acuity and takes account of patients who sutures were successively removed and finally have been followed up for different lengths of two additional sutures were inserted, leaving time. Figure 1 plots the probability of achiev-

Table I Patient data

Patient Age Pre-operative Follow-up Post-operative Post-operative number (years) spectacle acuity (months) refraction spectacle acuity

1 20 CF 28 + 1.00/- 2.00 x 142 6/6 2 20 6/60 25 + 0.50/- 1.50 x 20 6/9 3 42 6/18 8 - 1.50/-11.00 x 115 6/12 4 28 6/60 22 - 0.50/- 2.00 x 90 6/6 5 34 6/24 18 - 8.00/- 2.25 x 70 6/6 6 19 6/60 14 -11.00/- 1.50 x 70 6/6 7 34 6/60 14 + 0.75/- 4.75 x 95 6/9 8 32 6/36 12 + 4.00/- 3.50 x 15 6/36 9 22 CF 11 - 4.50/- 2.00 x 40 6/9 10 16 CF 8 - 3.50/ 6/6 11 28 6/36 7 + 1.00/- 0.50 x 160 6/6 12 26 CF 7 + 3.25/- 2.50 x 160 6/12 13 18 6/60 7 - 3.00/- 2.50 x 150 6/9 14 18 CF 7 - 6.25/- 0.25 x 85 6/6 15 17 6/60 4 + 0.50/- 2.00 x 80 6/12

CF = counting fingers. 534 BREIT. L. HALLIDAY

� 1.0 patients improved to 6/6 after epikerato­ :::J phakia. � 0.8 In the absence of irregular astigmatism a '0 �0.8 small discrete corneal scar may only slightly· impair visual acuity. It is therefore possible ill.�OA that patients with such scars may benefit from epikeratophakia. It is intended to widen the 0.2 inclusion criteria for epikeratophakia to

o include patients with corneal scars where o 2 4 8 8 10 there is a relative contra-indication to pen­ Months from surgery etrating keratoplasty such as susceptibility to trauma and previous complicated penetrating Fig. 1. Kaplan-Meir type plot showing the cumulative keratoplasty in the fellow eye. probability of achieving a given visual acuity against This study has confirmed that epikera­ time after surgery. Dotted line-6/6; Dashed line-6/9; Solid line-6/12. tophakia can improve spectacle corrected acuity in selected keratoconus patients. There was no undue delay in the recovery of acuity, ing visual acuities of 6/12, 6/9 and 6/6 against the majority of patients achieved 6/12 or bet­ the time from surgery. All the patients are ter and complications were confined to suture included in this plot. problems and astigmatism. If these results are confirmed over the long term then epikera­ tophakia may become the treatment of choice for intolerant patients who have Discussion relatively clear corneas. The length of follow-up in this series (average 13 months) is relatively short when compared to the natural history of keratoconus. While References these results appear to be encouraging, it 1 Kennedy RH, Bourne WM, Dyer JA: A 48 year clini­ remains to be seen whether the improvement cal and epidemiologic study of keratoconus. Am J in spectacle corrected acuity persists in the Ophthalmol1986, 101: 267-73. 2 Lass JH, Lembach RG, Park SB, Hom DL, Fritz long term. ME, et al. Clinical management of keratoconus, a One patient required penetrating kerato­ multicentre analysis. 1990, 97: plasty after epikeratophakia. The epikera­ 433-45. tophakia lens was removed at the 3 Paglen PG, Fine M, Abbott RL, Webster RG: The prognosis for keratoplasty in keratoconus. Oph­ using topical anaesthesia. Penetrating kera­ thalmology 1982, 89: 651-4. toplasty was performed two months later 4 McDonald MB, Kaufman HE, Durrie DS, Keates when the pre-existing partial thickness tre­ RH, Sanders DR: Epikeratophakia for keratoco­ phination was extended to full depth then a nus, the nationwide study. Arch Ophthalmol986, donor cornea sutured in place. It has been 104: 1294-300. 5 Lass JH, Stocker EG, Fritz ME, Collie DM: Epi­ suggested that prior epikeratophakia may keratoplasty, the surgical correction of , increase the risk of rejection episodes in a sub­ and keratoconus. Ophthalmology 1987, sequent penetrating graft,8 but no rejection 94: 912-25. has been seen in this patient who is now 14 6 Dietze TR and Durrie DS: Indications and treatment of keratoconus using epikeratophakia. Ophthal­ months from surgery. mology 1988, 95: 236-44. All of the patients treated had relatively 7 Steinert RF and Wagoner MD: Long-term compari­ clear corneas without discrete corneal scars. son of epikeratoplasty and penetrating kerato­ Where a diagnostic contact lens was tried pre­ plasty for keratoconus. Arch Ophthalmol 1988, operatively this usually gave good acuity, 106: 49H. 8 Frantz JM, Limberg MB, Kaufman HE, McDonald although two patients (numbers 6 and 11), MB: Penetrating keratoplasty after epikera­ when fitted with a hard contact lens, only tophakia for keratoconus. Arch Ophthalmol managed to achieve 6/18 acuity. Both of these 1988, 106: 1224-7.