British Journal of Ophthalmology, 1986, 70, 55-59

Photokeratoscopy in fitting contact lens afterpenetrating keratoplastyREIZO MANABE, MAMORU MATSUDA, AND TSUNEJI SUDA

From the Department of Ophthalmology, Osaka University Medical School, 1-1-50 Fukushima,Fukushima-ku, Osaka 553, Japan

SUMMARY The formula based on keratometric readings which is generally used is unsatisfactoryfor fitting contact lenses after penetrating keratoplasty, possibly owing to lack of information onthe peripheral corneal toricity. In these studies a photokeratoscope was used to examine the entiregraft topography. In all cases the corneal configuration became more normal after suture removal,but a considerable toricity still remained, especially near the graft-host junction. One month afterremoval of sutures spherical hard contact lenses (polymethylmethacrylate, PMMA) were fitted to30 patients in accordance with data obtained by computerised analysis of the photokeratograms.Of the 30 patients (contact lens wearers) 27 (90%) obtained a stable vision of better than 20/30 foreight hours daily, and 24 (80%) achieved a stable vision of 20/20 for their full waking hours. Afterone year the contact lens wearers showed a significant decrease in the extent of astigmatism whencompared with the non-contact-lens wearers (10 patients). These results suggest that thephotokeratoscope can be more useful than ordinary keratometers in fitting contact lenses afterkeratoplasty, and that hard contact lenses have moulding effects on the graft topography.

Improvements in surgical techniques and postopera-tive care have resulted in a higher rate of clear graftsafter penetrating keratoplasty. However, there are aconsiderable number of cases with a high degree ofcorneal astigmatism and ametropia, which preventgood vision. Although surgeons attempt to obtainemmetropic anastigmatic transplants, no reliablereproducible techniques have yet been established."Because most postkeratoplasty patients have some

degree of corneal irregular astigmatism, contactlenses, especially hard contact lenses, are requiredfor satisfactory visual rehabilitation.6 However, con-ventional methods for fitting contact lenses, based onkeratometric readings, do not apply to thesepatients.7 Ordinary keratometers provide onlymeasurements of the apical corneal curvaturesapproximately 2 mm from the visual axis, while ahigher degree of toricity is often present near thehost-graft junction. To obtain successful results good

Correspondence to Mamoru Matsuda, MD, Department ofPhysiology, Medical College of Wisconsin, 8701 Watertown PlankRoad, Milwaukee, WI 53226, USA. Reprint requests to ReizoManabe, MD, Department of Ophthalmology, Osaka UniversityMedical School, 1-1-50 Fukushima, Fukushima-ku Osaka 553,Japan.

relationships between a lens and the central andperipheral cornea are of great importance. Thereforeit can be said that the lack of information on theperipheral corneal toricity may be closely related todifficulties in fitting contact lenses after keratoplasty.

In this study the entire corneal topography wasexamined with a photokeratoscope, and hard contactlenses were fitted in accordance with the dataobtained by computerised analysis of the photo-keratograms.8

Patients and methods

Forty patients with unilateral phakic corneal trans-plants were studied. The preoperative diagnoses ofthese patients included keratoconus (25 eyes), herpessimplex stromal keratitis (8 eyes), and leucoma ofunknown aetiology (7 eyes). None had evidence ofretinal diseases, including age-related maculardegeneration and clinically significant cystoidmacular oedema. The ages of the patients rangedfrom 15 to 75 years (mean 47 years). Hard contactlenses (polymethylmethacrylate, PMMA) were fittedto 30 patients (contact lens wearers), while lenseswere not prescribed for the other 10 patients (non-

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Reizo Manabe, Mamoru Matsuda, and Tsuneji Suda

contact-lens wearers) because they could notmanipulate the lenses owing to poor dexterity. Thelatter group were used as controls in a study of theeffect of contact lens wear on postkeratoplastyastigmatism.

All keratoplasties were performed by one surgeon(RM) under local anaesthesia. The corneal buttonwas removed from the epithelial side with a trephine(7 to 8-5 mm in diameter) and secured in place witheight interrupted 9-0 virgin silk sutures followed by asingle 10-0 nylon monofilament running suture.9"After reformation of the anterior chamber of the eyewith a balanced salt solution, the interrupted sutureswere removed. The running suture was removed sixto 12 months (mean 10 months) postoperatively. Allcorneas were serially examined with a photokerato-scope (SUN PKS-1000) which measures the entirecorneal topography (Fig. 1). The photokeratogramsobtained were subjected to a computerised analysingsystem' that calculated the entire corneal configura-

tion as well as the keratometric readings" (Figs. 2 and3, middle). In the corneas where the mire imageswere out of focus owing to highly irregular orextensive curvatures the midpoint of the blurred mireimages was analysed to calculate the averagekeratometric readings.

Contact lenses were fitted in accordance with thedata obtained by photokeratoscopy and refraction ofthe eye. This procedure was done at one month aftersuture removal, during which the corneal epithelialdefects associated with the suture removal werecompletely healed in all the cases studied. Sphericalcontact lenses with a diameter of at least 1 mm largerthan the grafts were fitted in order to minimisedamage to the host-graft junction. An acceptable fitwas considered to be a lens with good centration andan adequate movement (1 to 2 mm) during blinkingto obtain proper tear exchange under the lens. Theproper tear exchange was designated as a washout offluorescein occurring in less than five minutes. The

PosJt. p. 7M Post op 2MBe ore siuoture removal

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Fig. 1 Sequentialphotokeratograms afterpenetrating keratoplasty.

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Photokeratoscopy infitting contact lens afterpenetrating keratoplasty

/ -4- -~ t 4;s3

Fig. 2 The corneal topography in a 41-year-old male with herpes stromal keratitis who underwent keratoplasty with an 8 mmcorneal button. Each number in the middlefigure represents the radius (mm) ofthe curvaturefor the respective region ofthecornea, which provided quantitativeparameters tofit a lens.

peripheral posterior curve of the lens was modifiedaccording to the peripheral corneal toricity, ifneeded, in order to obtain a better lens-cornearelationship.

Results

In all the cases studied the corneal topography wasquite flat and irregular during the early period afterpenetrating keratoplasty (Fig. 1, left), but it becamesteeper and more regular with time (Fig. 1, middle).Suture removal resulted in sudden changes in thegraft topography (Fig. 1, middle and right). Therewas considerable individual variation in the degree ofthese topographic changes. After suture removal theconfiguration of the central cornea became morespherical, but a considerable toricity still remained,especially near the host-graft junction (Fig. 1, right).

Fig. 2 shows the corneal topography in a 41-year-old male with herpes stromal keratitis who under-went keratoplasty with an 8 mm corneal button.Because the cornea had flatter than normal centraland peripheral curvatures'2 (Fig. 2, middle), a lenswith a diameter of 9-2 mm and a central posterior(base) curve of 8*65 mm was fitted, and theperipheral posterior curve of the lens was modified tobe flatter. This patient has been wearing the lens forhis full waking hours with a stable vision of 20/20.

Fig. 3 shows the corneal topography in a 24-year-old female with keratoconus undergoing kerato-plasty with a 7*5 mm graft. Because the cornea hadsteeper than normal central curvatures and flatterthan normal peripheral curvatures' (Fig. 3, middle),a lens with a diameter of 9-5 mm and a base curve of7*35 mm was fitted and the peripheral posterior curveof the lens was also modified to be flatter. The patient

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\s . . v _ . X S . W . 0 _ f IUFig. 3 The corneal topography in a 24-year-oldfemale with keratoconus who underwent keratoplasty with a 7-5 mm graft.Each number in the middlefigure represents the radius (mm) ofthe curvaturefor the respective region ofthe cornea, whichprovided quantitativeparameters to design a lens.

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Reizo Manabe, Mamoru Matsuda, and Tsuneji Suda

Table 1 Changes in corneal astigmatism

Contact lens A verage astigmatism (dioptres)wear

0* 3 months 6 months 12 months

Yes (n=30) 4 5 2-7 2-5 2-2No(n=10) 4-2 4 0 3-8 3-5

NS NS NS p

Photokeratoscopy infitting contact lens afterpenetrating keratoplasty

refractive surgery, such as relaxing incisions or wedgeresection.'5As reported previously,667 we found that the graft

topography is in a state of transition for severalmonths after suture removal. We also found prospec-tively that the contact lens wearers have a significantdecrease in the extent of corneal astigmatism afterone year of lens wear when compared with the non-contact-lens wearers. A similar observation has beenmade in a retrospective study by Ruben andColebrook.'7 These findings indicate that contactlenses have a moulding effect on the grafttopography.6'7

We thank Mr Etsuji Adachi (SUN Contact Lens Co. Ltd., Kyoto,Japan) for his valuable technical assistance in this study.

References

1 Troutman RC, Meltzer M. Astigmatism and myopia inkeratoconus. Trans Am Ophthalmol Soc 1972; 70: 265-77.

2 Troutman RC. Microsurgical control of corneal astigmatism incataract and keratoplasty. Ophthalmology (Rochester) 1973; 77:563-72.

3 Troutman RC, Kelly S, Kaye D, Clahane AC. The use andpreliminary results of Troutman surgical keratometer in cataractand corneal surgery. Ophthalmology (Rochester) 1977; 83:232-8.

4 Troutman RC. Astigmatic considerations in corneal graft.Ophthalmic Surg 1979; 10: 21-6.

5 Troutman RC, Gaster RN. Surgical advances and results ofkeratoconus. Am J Ophthalmol 1980; 90: 131-6.

6 Daniel R. Fitting contact lenses after keratoplasty. Br JOphthalmol 1976; 60: 263-5.

7 Garcia GE. Contact lens fitting in keratoconus and followingkeratoplasty. In: Leibowitz HM. Corneal disorders.Philadelphia: Saunders, 1984: 678-82.

8 Kuyama H, Sasamoto K, Maruyama S, Itoi M. A new photo-keratoscope for contact lens in clinic. J Jpn Contact Lens Soc1979; 21: 80-4.

9 Matsuda M, Suda T, Manabe R. Long-term observations on thegraft endothelium with different postoperative courses. Jpn JOphthalmol 1983; 27: 556-66.

10 Matsuda M, Suda T, Manabe R. Serial alterations in endothelialcell shape and pattern after intraocular surgery. Am JOphthalmol 1984; 98: 313-9.

11 Matsuda M, Suda T, Manabe R. Quantitative analysis ofendothelial mosaic pattern changes in anterior keratoconus. AmJ Ophthalmol 1984; 98: 43-9.

12 Hasegawa S, Masuda N, Terao N, Inatomi A. Cornealtopography using the photokeratoscope. J Jpn Contact Lens Soc1981; 23: 208-14.

13 Suda T, Matsuda M, Manabe R, Adachi E. Evaluation of thefitting of hard contact lenses for keratoconus. JJpn Contact LensSoc 1982; 24: 84-94.

14 Maruyama S, Suda T, Inoue Y, Matsuda M. Computerizedcontact lens designing system for keratoconus. J Jpn ContactLens Soc 1983; 25: 185-90.

15 Krachmer JH, Fenzel RE. Surgical correction of high post-keratoplasty astigmatism. Arch Ophthalmol 1980; 98: 1400-2.

16 Matsuda M, Suda T, Manabe R. Chronological changes of grafttopography after penetrating keratoplasty. Folia OphthalmolJpn 1981; 32: 1347-52.

17 Ruben, M, Colebrook E. Keratoconus keratoplasty curvaturesand contact lens wear. BrJ Ophthalmol 1979; 63: 268-73.

Acceptedfor publication 25 April 1985.

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